Toshiba GRT100 User Manual

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INSTRUCTION MANUAL

TRANSFORMER PROTECTION RELAY

GRT100 - ∗∗∗D

( Ver. 4.0 )

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Safety Precautions

Before using this product, be sure to read this chapter carefully. This chapter describes safety precautions when using the GRT100. Before installing and using the

equipment, read and understand this chapter thoroughly.

Explanation of symbols used

Signal words such as DANGER, WARNING, and two kinds of CAUTION, will be followed by important safety information that must be carefully reviewed.

Indicates an imminently hazardous situation which will result in death or

DANGE

Indicates a potentially hazardous situation which could result in death or

WARNING

CAUTION Indicates a potentially hazardous situation which if not avoided, may result in

serious injury if you do not follow instructions.

minor injury or moderate injury.

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CAUTION Indicates a potentially hazardous situation which if not avoided, may result in

property damage.

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DANGE

• Current transformer circuit

Never allow the current transformer (CT) secondary circuit connected to this equipment to be opened while the primary system is live. Opening the CT circuit will produce a dangerous high voltage.

WARNING

• Exposed terminals

Do not touch the terminals of this equipment while the power is on, as the high voltage generated is dangerous.

• Residual voltage

Hazardous voltage can be present in the DC circuit just after switching off the DC power supply. It takes about 30 seconds for the voltage to discharge.

• Fiber optic

Do not view directly with optical instruments.

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CAUTION

• Earth

Earth the earthing terminal of the equipment securely.

CAUTION

• Operation conditions

Use the equipment within the range of ambient temperature, humidity and dust as detailed in the specification and in an environment free of abnormal vibration.

• Ratings

Before applying AC voltage and current or DC power supply to the equipment, check that they conform to the equipment ratings.

• Printed circuit board

Do not attach and remove the printed circuit board while the DC power to the equipment is on, as this may cause the equipment to malfunction.

• External circuit

When connecting the output contacts of the equipment to an external circuit, carefully check the supply voltage used and prevent the connected circuit from overheating.

• Connection cable

Carefully handle the connection cable without applying excessive force.

• Modification

Do not modify this equipment, as this may cause the equipment to malfunction, and any such modifications will invalidate the warranty.

• Short-link

Do not remove a short-link which is mounted at the terminal block on the rear of the relay before

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shipment, as this may cause the performance of this equipment such as withstand voltage, etc., to reduce.

• Disposal

When disposing of this product, do so in a safe manner according to local regulations. This product contains a lithium-ion battery, which should be removed at the end-of-life of the

product. The battery must be recycled or disposed of in accordance with local regulations. The battery can be removed by withdrawing the Signal Processing module (SPM) from the relay case, and cutting the connecting leads and plastic strap which hold the battery.

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Contents

Safety Precautions 1

1. Introduction 8

2. Application Notes 10

2.1 Protection Scheme 10

2.2 Current Differential Protection 12

2.3 Restricted Earth Fault Protection 34

2.4 Overcurrent Protection 38

2.5 Thermal Overload Protection 43

2.6 Frequency Protection 44

2.7 Overexcitation Protection 46

2.8 Trip by External Devices 48

2.9 Tripping Output 49

2.10 Characteristics of Measuring Elements 51

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2.2.1 Differential Scheme 12

2.2.2 Stability for CT Saturation during Through-fault Conditions 16

2.2.3 Matching of CT Secondary Currents 18

2.2.4 Connection between CT Secondary Circuit and the GRT100 22

2.2.5 Setting 23

2.10.1 Percentage Current Differential Element DIF 51

2.10.2 High-set Overcurrent Element HOC 52

2.10.3 Restricted Earth Fault Element REF 52

2.10.4 Inverse Time Overcurrent Element OCI and EFI 54

2.10.5 Definite Time Overcurrent element OC and EF 55

2.10.6 Thermal Overload Element THR 55

2.10.7 Frequency Element FRQ 57

2.10.8 Overexcitation Element V/F 57

3. Technical Description 58

3.1 Hardware Description 58

3.1.1 Outline of Hardware Modules 58

3.1.2 Transformer Module 61

3.1.3 Signal Processing Module 62

3.1.4 Binary Input and Output Module 63

3.1.5 Human Machine Interface (HMI) Module 67

3.2 Input and Output Signals 69

3.2.1 Input Signals 69

3.2.2 Binary Output Signals 70

3.2.3 PLC (Programmable Logic Controller) Function 71

3.3 Automatic Supervision 72

3.3.1 Basic Concept of Supervision 72

3.3.2 Relay Monitoring and Testing 72

3.3.3 PLC Data and IEC61850 Mapping Data Monitoring 73

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3.3.4 IEC61850 Communication Monitoring 73

3.3.5 Failure Alarms 73

3.3.6 Trip Blocking 74

3.3.7 Setting 74

3.4 Recording Function 75

3.4.1 Fault Recording 75

3.4.2 Event Recording 76

3.4.3 Disturbance Recording 76

3.5 Metering Function 78

4. User Interface 79

4.1 Outline of User Interface 79

4.1.1 Front Panel 79

4.1.2 Communication Ports 81

4.2 Operation of the User Interface 82

4.2.1 LCD and LED Displays 82

4.2.2 Relay Menu 84

4.2.3 Displaying Records 87

4.2.4 Displaying the Status 90

4.2.5 Viewing the Settings 95

4.2.6 Changing the Settings 95

4.2.7 Testing 114

4.3 Personal Computer Interface 118

4.4 Communication Interface 118

4.4.1 RSM (Relay Setting and Monitoring System) 118

4.4.2 IEC 60870-5-103 Interface 119

4.4.3 IEC 61850 interface 120

4.5 Clock Function 120

5. Installation 121

5.1 Receipt of Relays 121

5.2 Relay Mounting 121

5.3 Electrostatic Discharge 121

5.4 Handling Precautions 121

5.5 External Connections 122

6. Commissioning and Maintenance 123

6.1 Outline of Commissioning Tests 123

6.2 Cautions 124

6.2.1 Safety Precautions 124

6.2.2 Cautions on Tests 124

6.3 Preparations 125

6.4 Hardware Tests 126

6.4.1 User Interfaces 126

6.4.2 Binary Input Circuit 127

6.4.3 Binary Output Circuit 128

6.4.4 AC Input Circuits 129

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6.5 Function Test 130

6.5.1 Measuring Element 130

6.5.2 Timer Test 146

6.5.3 Protection Scheme 148

6.5.4 Metering and Recording 148

6.6 Conjunctive Tests 149

6.6.1 On Load Test 149

6.6.2 Tripping Circuit Test 149

6.7 Maintenance 151

6.7.1 Regular Testing 151

6.7.2 Failure Tracing and Repair 151

6.7.3 Replacing Failed Modules 153

6.7.4 Resumption of Service 155

6.7.5 Storage 155

7. Putting Relay into Service 156

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Appendix A Block Diagram 157 Appendix B Signal List 159 Appendix C Variable Timer List 179 Appendix D Binary Output Default Setting List 181 Appendix E Details of Relay Menu and LCD & Button Operation 185 Appendix F Case Outline 193 Appendix G External Connections 199 Appendix H Relay Setting Sheet 207 Appendix I Commissioning Test Sheet (sample) 241 Appendix J Return Repair Form 247 Appendix K Technical Data 253 Appendix L Setting of REF Element 261 Appendix M Symbols Used in Scheme Logic 267 Appendix N Implementation of Thermal Model to IEC60255-8 271 Appendix O IEC60870-5-103: Interoperability and Troublehsooting 275 Appendix P IEC61850: MICS & PICS 287 Appendix Q Inverse Time Characteristics 321 Appendix R Failed Module Tracing and Replacement 325 Appendix S Ordering 331

 The data given in this manual are subject to change without notice. (Ver.4.0)

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1. Introduction

GRT100 provides high-speed transformer and reactor protection, and realises high dependability and security for diverse faults such as single-phase faults, multi-phase faults, overload and over-excitation.

GRT100 is used as a main protection and backup protection of the following transformers and reactors.

• Two-winding or three-winding power transformers

• Auto-transformers

• Generator-transformer units

• Shunt reactors

GRT100 is designed to provide stability under magnetizing inrush and overexcitation conditions. GRT100 is available for mixed 1A/5A inputs

GRT100 provides the following metering and recording functions.

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• Metering

• Fault records

• Event records

• Disturbance records

GRT100 provides the following human interfaces for relay setting or viewing of stored data.

• Relay front panel: LCD, LED display and operation keys

• Local PC

• Remote PC

Password protection is provided to change settings. Eight active setting groups are provided. This allows the user to set one group for normal operating conditions while other groups may be set to cover alternative operating conditions by binary input using the PLC.

GRT100 can provide the following serial interface ports:

- RS232C for a local PC and Relay Setting and Monitoring System (RSM100)

- RS485 for a remote PC, and Relay Setting and Monitoring System (RSM100) or Substation control and Automation System (SAS) with IEC60870-5-103 protocol

- Fibre Optic (FO, option) for a remote PC, and Relay Setting and Monitoring System (RSM100) or Substation control and Automation System (SAS) with IEC60870-5-103 protocol

- 100BASE-TX, or -FX (option) for Substation control and Automation System (SAS) with IEC61850 protocol

Another interface IRIG-B port is provided for an external clock connection. The RS232C port is located on the front panel of the relay. Other ports (RS485, FO, 100BASE-TX

and IRIG-B) are located on the rear of the relay.

Further, the GRT100 provides the following functions.

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- Configurable binary inputs and outputs

- Programmable logic for I/O configuration, alarms, indications, recording, etc.

- Automatic supervision

GRT100 has two model series which differ according to the number of three-phase current inputs for differential protection as follows:

Relay Type and Model

Relay Type:

- Type GRT100; Numerical transformer protection relay

Relay Model:

- Model 100 series; 2 three-phase current inputs, applied to two-winding transformers

• Model 101; 16 binary inputs, 13 binary outputs, 5 binary outputs for tripping

• Model 102; 16 binary inputs, 23 binary outputs, 5 binary outputs for tripping

- Model 200 series; 3 three-phase current inputs, applied to two- and three-winding transformers

• Model 201; 16 binary inputs, 13 binary outputs, 5 binary outputs for tripping

• Model 202; 16 binary inputs, 23 binary outputs, 5 binary outputs for tripping

• Model 203; 15 binary inputs (12-independent), 13 binary outputs, 3 binary outputs for tripping

• Model 204; 15 binary inputs (12-independent), 23 binary outputs, 3 binary outputs for tripping

Model 100 series have 2 three-phase current inputs and can be applied to two-winding transformers. Model 200 series have 3 three-phase current inputs and can be applied to two- and three-winding transformers.

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2. Application Notes

GRT100 is applied to both main protection and backup protection for the following transformers and reactors:

• Two-winding or three-winding power transformers

• Auto-transformers

• Generator-transformer units

• Shunt reactors

2.1 Protection Scheme

GRT100 provides the following protection schemes with measuring elements in parentheses. Appendix A shows the block diagrams of the GRT100 series.

• Current differential protection (DIFT)

• Restricted earth fault protection (1REF-3REF)

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• Time-overcurrent protection (1OC-3OC, 1OCI-3OCI, 1EF-3EF and 1EFI-3EFI)

• Thermal overload protection (THR)

• Frequency protection (FRQ)

• Overexcitation protection (V/F)

• Trip and/or indication of external devices (Buchholtz relay, pressure or temperature sensing

devices etc.)

The DIFT, provided with DIF and HOC elements and the REF are applied for main protection. For details, see Sections 2.2, 2.3 and 2.10.

They provide transformer protection coverage as follows: REF: protection for winding to earth faults of star-winding side DIF: protection for all internal transformer faults (The DIF can be blocked by 2F or 5F

element.)

HOC: protection for all internal transformer faults, specifically for heavy internal faults,

high-speed operation (The HOC is not blocked by 2F or 5F element. The sensitivity is set above the estimated maximum inrush current.)

DIF

HOC

REF

For earth fault only

Small

The number of measuring elements for the restricted earth fault protection and time-overcurrent protection is dependent on the relay models.

Figure 2.1.1, 2.1.2 and 2.1.3 show typical application and the relationship between AC inputs and the measuring elements applied in each model.

Differential current

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1CT

2CT

2nCT

GRT100

1OC/1OCI THR

FRQ V/F

Calculate 3I0

1nCT

2nCT

1EF/1EFI

2OC/2OCI

2EF/2EFI

1REF

2REF

Figure 2.1.1 Measuring Elements of Model 100 series

GRT100

1CT

3CT

1nCT 3nCT

1OC/1OCI THR

FRQ V/F

1EF/1EFI

Calculate 3I0

1REF

DIFT

Calculate 3I0

DIFT

1CT

3CT

2CT

2OC/2OCI

2EF/2EFI

3OC/3OCI

3EF/3EFI

Figure 2.1.2 Measuring Elements of Model 200 series

GRT100

1OC/1OCI

2CT

1nCT

2OC/2OCI

FRQ V/F

1EF/1EFI

3OC/3OCI

Calculate 3I

1REF

Calculate 3I0

2REF

Calculate 3I0

3REF

Calculate 3I0

DIFT

Figure 2.1.3 Measuring Elements of Model 200 series

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2.2 Current Differential Protection

2.2.1 Differential Scheme

Current differential protection DIFT provides an overall transformer protection deriving phase current from each transformer winding, calculating the differential current on a per phase basis and detecting phase-to-phase and phase-to-earth faults.

The current differential protection is based on Kirchhoff’s first law that the vector summation of all currents flowing into a protected zone must be zero. Figure 2.2.1.1 shows the principle of current differential protection. Differential current (id) is the vector summation of all terminal current of the transformer. The differential current (id=i1+i2) is zero because the current (i1) equals current (−i2) during a load condition or an external fault. During an internal fault, the differential current (id) is not zero because the current (i1) does not equal to the current (−i2), and the DIFT operates.

Primary

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Secondary

Transformer

id=i1+i2

Differential cu r r ent detection

Figure 2.2.1.1 Current Differential Protection

DIFT

Scheme logic

Figure 2.2.1.2 shows the scheme logic of the current differential protection. Current differential element DIFT comprises sub-elements HOC, DIF, 2F and 5F which operate for differential current on a per phase basis.

Note: For the symbols used in the scheme logic, see Appendix M. HOC is a high-set overcurrent element operating for differential current. It provides high-speed

protection for heavy internal faults. DIF is a percentage restraining element and has dual restraining characteristics, a weak restraint in

the small current region and a strong restraint in the large current region, to cope with erroneous differential current which may be caused due to output imbalance of the CTs in case of an external fault. (For the characteristics, see Section 2.10.)

The DIF output signal can be blocked when the 2F or 5F elements detect second harmonic inrush current during transformer energization or fifth harmonic components during transformer overexcitation. Blocking is enabled by setting scheme switch [2F-LOCK] or [5F-LOCK] to “ON”. The following two or three blocking schemes are selectable by scheme switch [DIFTPMD].

“3POR”: When any one phase of the 2F or 5F element operates, tripping by the DIF

element is blocked in all 3 phases. “3POR” is recommended for transformers with large capacity whose second harmonic component may be low. Its blocking function is stronger than that of the “1P” or “2PAND” below.

“1P”: When any phase of the 2F or 5F elements operate, only the corresponding phase

output of the DIF element is blocked.

“2PAND”: Even if 2F or 5F element operates during manetising inrush, the trip by DIF

element is allowed when any two phases or more of DIF element operate.

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DIFT

1616 1617 1618

HOC-A

HOC-B

HOC-C

DIF-A

DIF-B

DIF-C

2F-A

2F-B

2F-C

5F-A

5F-B

5F-C

2F-Lock

5F-Lock

DIF-A_BLOCK DIF-B_BLOCK DIF-C_BLOCK

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“2PAND” is recommended for a transformer with small or midium capacity whose second harmonic component in inrush current is genarally higher than that of transformer with large capacity. This mode is applicable if [Phase matching] is set to “Beta”.

Protection by DIF and HOC can perform instantaneous three-phase tripping of up to five breakers. Any of the five breaker tripping signals DIFT-1 to DIFT-5 are enabled or disabled by the scheme switch [DIF1] to [DIF5] settings.

Note: Models 203 and 204 are not provided with DIFT-4 and DIFT-5, and perform tripping of up to

three breakers.

HOC

374

≥1

DIF

121

100

1 1 1

≥1

122

≥1

123

≥1 1

DIFTPMD +

3POR 1P 2PAND (*2)

Note:

(*1) Models 203 and 204 are not provided with DIFT-4 and DIFT-5. (*2) [Phase matching]="Beta" setting only

≥1

224

≥1

DIF1

DIF2

DIF3

DIF4

DIF5

TRIP

DIFT-1

DIFT-2

DIFT-3

DIFT-4 (*1)

DIFT-5 (*1)

DIF

HOC

≥1

330

331

352

DIFT-DIF TP

DIFT-HOC TP

DIFT TRIP

Figure 2.2.1.2 Scheme Logic of Current Differential Protection

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Display mode following differential tripping

Following a trip output, GRT100 can display either the operating phase or the faulted phase according to the user’s requirements as shown in Table 2.2.1.1. The operating phase or faulted phase display is selectable by a setting in the Record menu.

Table 2.2.1.1 Operating Phase / Faulted Phase Display

Operating phase display Faulted phase display

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Setting (Setting/Record/Fault record/Phase mode)

Displayed phase Operating phase

Application All two- and three-winding transformers

1 = Operating 2 = Fault

Generally, the operating phase of the DIF element does not correspond with the faulted phase, but depends on the transformer configuration and the electrical quantities that are input to the GRT100 current differential calculation.

Faulted phase (for single-phase to earth, phase to phase, two-phase to earth and three-phase to earth faults)

• Faults at primary side or secondary side of Yy0

and Yy6 transformers

• Faults at primary side of Yd1, Yd3, Yd5, Yd7,

Yd9, Yd11, Yy2, Yy4, Yy8 and Yy10 transformers

• Faults at secondary side of Dy1, Dy3, Dy5, Dy7,

Dy9 and Dy11 transformers

• Faults on Dd2, Dd4, Dd6, Dd8 and Dd10

transformers, faults at Zig-zag connected side of transformers and faults at tertiary side of three-winding transformers are not supported.

Logic Refer to Figure 2.2.1.4.

∗ Phase (A/B/C) display is based on the operating signal of DIF or HOC element, and “N” display is based on the operating signal of REF and DIFT elements. If the REF is not used, “N” is not displayed.

Refer to Figure 2.2.1.4. ∗ Phase (A/B/C) display is based on the operating

signal of DIF or HOC element and a differential current value, and “N” display is based on the operating signal of REF and DIFT elements. If the REF is not used, “N” is not displayed.

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DIFT

HOC-A

HOC-B

HOC-C

DIF-A

DIF-B

DIF-C

2F-A

2F-B

2F-C

5F-A

5F-B

5F-C

2F-Lock

5F-Lock

[Op erating phase]

≥1

121

DIF

100

≥1

1REF

1REF1

1REF5

2REF

2REF1 +

2REF5

3REF

3REF1 +

3REF5

≥1

Fau lt ed phase

& ≥1

Not e: Mod els 203 and 20 4 are not provided with 1RE F-4,

1REF-5, 2R EF-4, 2REF-5, 3REF-4 and 3REF -5.

selection logic

[Fau lted ph ase]

Phas e A

Phas e B

Phas e C

Phas e N

Figure 2.2.1.4 Operating Phase and Faulted Phase Selection Logic

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2.2.2 Stability for CT Saturation during Through-fault Conditions

For current differential protection of transformers, GRT100 has a strong restraint characteristic in the large current region for erroneous differential current due to CT saturation. Further, GRT100 provides a CT saturation countermeasure function. If any CTs saturate due to a large through-fault current, an apparent differential current is generated in the differential circuit and may cause false operation of the differential protection.

Operation Principle

Even when a CT saturates under very large primary currents, the waveform of the saturated CT secondary current has two identifiable periods in each cycle: a non-saturated period and a saturated period. The GRT100 utilizes this phenomenon and provides very secure operation for external faults with a large through-fault current.

Figure 2.2.2.1 shows a block diagram of the CT saturation countermeasure (CTS). The CTS has a waveform discriminating element (WDE) and starting element (SE). WDE operates if the change in the instantaneous value of the differential current is less than a specified percentage of the change in the instantaneous value of the restraining current. In the CTs non-saturated period, the differential current is theoretically zero for through-fault currents. The element operates in this period.

Current Input

Figure 2.2.2.1 Differential Element with CT Saturation Countermeasure

Differential Element (DIFT_DIF)

Waveform Discriminating Element

Starting Element

[CTSEN]

CTS

The algorithm of this element is given by the following equation:

ΔId < 0.15×(ΔIp + ΔIn)

where,

ΔId : Change in the differential current Id (ΔIp + ΔIn) : Change in the restraining current in the positive and negative cycles

Tripping Output

Id : Differential current Ip : Sum of positive input currents In : Sum of negative input currents

SE operates when the sum of the absolute values of the difference between the instantaneous values of current data at each current input from one cycle is greater than 0.5 × (CT secondary rated current).

SE discriminates between healthy and faulty power system conditions and blocks the output of WDE which may otherwise operate during healthy conditions.

Figure 2.2.2.2 shows CT secondary current waveforms of the incoming and outgoing terminals,

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and also the differential current at the time of an external fault with outgoing terminal CT saturation.

Incoming terminal current

Outgoing terminal current

Differential current

No change period

Figure 2.2.2.2 CT Secondary Current Waveforms and Differential Current for an External

Fault with CT Saturation

From the inception of the fault until the CT secondary current at the outgoing terminal saturates, the differential current Id is zero and the change in the differential current ΔId obtained from equation (2) is also zero. However, the change in the restraining current given by equation (3) is a sufficiently large positive value, so equation (1) is met and WDE operates.

SE detects changes in the terminal currents and rapidly operates, producing an AND output with WDE. After this, since there is a period during which equation (1) is not satisfied, a certain time delay is inserted to reliably block the operation of the DIFT_DIF differential element.

If, during an internal fault, there is a period during which the change in the instantaneous value of the differential current is small due to CT saturation, WDE will not operate because the change in the restraining current is also small during that period. Thus, during an internal fault, operation of the differential element is not blocked falsely.

The CTS function can be disabled by the scheme switch [CTSEN].

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2.2.3 Matching of CT Secondary Currents

The currents supplied to the differential elements must be matched in phase displacement and amplitude under through-load and through-fault conditions.

Generally, it is difficult to completely match the incoming current with the outgoing current for the relay input because the CT ratios at the primary, secondary and tertiary sides of a transformer are not matched in terms of the CT ratio, phase angle and cancelling of zero-sequence current.

GRT100 provides the following matching method:

CT ratio: N1

Ip/N1=i1

GRT100

Matching of phase

angle / Zero-sequence

current elimination

Matching of CT ratio Matching of CT ratio

Primary

Transformer

i1 Kct2×i2

Kct1

Differential relay calculation

Secondary

Is CT ratio: N2

Is/N2=i2

Matching of phase

angle / Zero-sequence

current elimination

Figure 2.2.2.1 Matching Method

GRT100 supports selectable two matching methods, α-method (Alpha) and β-method (Beta). The method is selected by the scheme switch [Phase matching].

Phase matching is performed by setting according to the hands of a clock and the transformer connections described in IEC60076-1. For details of the setting, refer to 2.2.5.

2.2.3.1 α-method phase matching

This method corrects the phase angle by using each winding current calculated as follows:

- Current substructed zero-sequence current from each phase current in Star- winding side of transformer

- Phase-to-phase Current in Delta-winding side of transformer

The followings show calculation formula and current vectors in an example of a transformer Yd11.

Isa

Isb

Isc

Ipa

Ip1

Ipb Ipc

&&&

pcIpbIpaI

−−

scIsaI

−

(1)

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&&&

−−

paIpcIpbI

&&&

pbIpaIpcI

−−

where,

Further, zero-sequence current is eliminated from the relay input current (Ip∗) for the calculation of the differential current as follows:

&&&

pcIpbIpaI

,, : Primary side terminal current of transformer

&&&

scIsbIsaI

,, : Secondary side terminal current of transformer

&&&

pI −=

−−

&&&

−− =

&&&

−− =

saIsbI

−

(2)

sbIscI

−

(3)

IpcIpbIpaIpapcIpbIpaI

++−

)(3

IpcIpbIpaIpbpaIpcIpbI

++−

)(3

IpcIpbIpaIpapbIpaIpcI

++−

)(3

IpoIpa

IpoIpb

IpoIpc

2.2.3.2 β-method (Traditional method) phase matching

This is a traditional method that delta current (phase-to-phase current) on the Star-winding side of a Star/Delta transformer and phase current on the Delta-winding side of that is introduced into a relay input for the calculation of the differential current. Traditionally, the phase matching is realized by Delta connecting the CTs on the Star-winding side and by Star connecting the CTs on the Delta-winding side. In GRT100, however, it is realized by software.

The followings show calculation formula and current vectors in an example of a transformer Yd11.

Ipa

Ip1

Ipb

−

pbIpaI

Is1

Isc

saIsI&&=1

(4)

pcIpbI

−

sbIsI&&=2

(5)

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−

paIpcI

scIsI&&=3

(6)

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2.2.3.3 Zero-sequence current elimination

In addition to compensating for the phase angle between the primary and secondary currents of the transforemer, also phase angle matching prevents unnecessary operation due to zero-sequence current during an external earth fault, such as in the following cases.

Case 1: When an external fault occurs at the star-connected side of the transformer shown in Figure

2.2.3.2, a zero-sequence current flows in star-connected side, but the zero-sequence current at the delta-side circulates in the delta winding. The zero-sequence current is only fed into the star winding side of the DIFT which is star-connected at the CT secondary, thus causing the DIFT to operate incorrectly. In α-method phase matching, the zero-sequence current is eliminated from a relay input current as described above. In β-method phase matching, the zero-sequence current is eliminated from the relay input current by Delta connection on the Star-winding side.

Since the DIFT provides a function to eliminate the zero-sequence current by software, the DIFT is insensitive the fault described.

Transforme

I I

DIFT

Figure 2.2.3.2 External Earth Fault at the Star-connected side of a Transformer

Case 2: When the delta winding of a power transformer is earthed through an earthing transformer as

shown in Figure 2.2.3.3 and the earthing transformer is located within the differential protection zone, in case of an external earth fault the zero-sequence current flows only on the delta side of the power transformer and appears as a differential current.

Earthing Transforme

DIF

Figure 2.2.3.3 External Earth Fault at the Delta-winding side of a Transformer with

in-zone Earthing Transformer

⎯ 20 ⎯

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6 F 2 S 0 8 5 7

In α-method phase matching, since the DIFT provides a function to eliminate the zero-sequence current by software, the DIFT is insensitive to the fault described.

In β-method phase matching, however, since the zero-sequence current is not eliminated because of Star connection on the Delta-winding side, the DIFT may operate unnecessary.

In case the GRT100 is applied to a transformer with in-zone earthing transformer, the [Phase matching] = “Alpha” setting is recommended.

2.2.3.4 Matching of CT Ratio

If I

to I3 correspond to 1CT to 3CT secondary currents, differential current Id is calculated

according to the following equation,

= kct1⋅I1 + kct2⋅I2 + kct3⋅I3

where kct1 to kct3 are settings corresponding to 1CT to 3CT. Setting kct1 is obtained by using the following equation. kct1 = I

= I

n/Ibase1

/( 3 × I

) if 1CT is delta-connected.

base1

where I

= rated secondary current of 1CT (1A or 5A)

I = transformer capacity(kVA)/( If the 1CT secondary circuit is delta-connected,

= secondary current of 1CT based on the kVA rating of the power transformer.

base1

3 × rated voltage(kV)) × CT ratio of 1CT

3 × I

is used instead of I

base1

above. Settings kct2 and kct3 are obtained in the same way. The differential current I kct1 × I

to kct3 × I3 are equal to the rated secondary current of each CT when the rated line

is zero under through-load and through-fault conditions.

currents based on the kVA rating of the power transformer flow.

in the equation

base1

⎯ 21 ⎯

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22 11

6 F 2 S 0 8 5 7

2.2.4 Connection between CT Secondary Circuit and the GRT100

GRT100 is provided with 2 or 3 three-phase current input terminals depending on the relay model. To validate the phase angle matching described previously and apply in-phase current from each

winding to the relay, connect the CT secondary circuits to the current input terminals of the relay as follows;

As shown below, the phases used in the phase angle setting (indicated by an arrowhead) must be connected to the AC input terminals with the lowest number in the terminal group such as 1, 9, 17, then the other two phases should be connected to the terminals with a larger number clockwise from the setting phase, such as 3 and 5, 11 and 13, or 19 and 21.

Primary

Tertiary

Secondary

1 5

2 4 6

17 19

GRT100

18 10

14 20

Figure 2.2.4.1 Connection of CT Secondary Circuit and the GRT100

Terminal numbers and corresponding input currents are shown in the following table.

Model Terminal block Terminal number Input current

100 series / 200 series TB1 1-2 3-4 Current of primary winding 5-6 9-10 11-12 Current of secondary winding 13-14 17-18 19-20 Current of tertiary winding 21-22

⎯ 22 ⎯

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6 F 2 S 0 8 5 7

2.2.5 Setting

The following shows the setting elements necessary for the current differential protection and their setting ranges. Setting can be performed on the LCD screen or PC screen.

Element Range Step Default Remarks

DIFT

DIF

0.10 − 1.00

(∗)

0.01 0.30 Minimum operating current

p1 p2 kp k2f k5f

HOC kh CT matching kct1 CT ratio kct2 kct3 Phase angle matching yd_p 1(star) / 2(delta) 1 Primary winding (α-method) yd_t 1(star) / 2(delta) 1 Tertiary winding vec_s 0 – 11 1 0 Phase angle difference between primary

vec_t 0 – 11 1 0 Phase angle difference between primary

If [Phase matching]=Alpha setting

yd_s 1(star) / 2(delta) 1 Secondary winding

10 − 100% 10 − 200%

1.00 − 20.00(*) 10 − 50% 10 − 100%

2.00 − 20.00(*)

0.05 − 50.00

1% 100% % slope of small current region 1% 200% % slope of large current region

0.01 1.00 Break point of dual characteristics 1% 15% Second harmonic detection 1% 30% Fifth harmonic detection

0.01 2.00 High-set overcurrent protection

0.01 1.00 Primary winding

0.01 1.00 Secondary winding

0.01 1.00 Tertiary winding

and secondary

and tertiary If [Phase matching]=Beta setting d1 (β-method) d3 Scheme switch

[Phase matching] Alpha / Beta Beta Matching methods of CT secondary

[DIFTPMD] 3POR / 1P 3POR Trip mode (if [Phase matching] = Alpha) [DIFTPMD] 3POR / 2PAND / 1P [2F – LOCK] Off / On On Block by second harmonic [5F - LOCK] Off / On On Block by fifth harmonic

[DIF1] to [DIF5] Off / On (**) Output tripping signal

[CTSEN] Off / On Off CT saturation function

(∗): Multiplier of CT secondary rated current including CT ratio correction. (**): Default settings are dependent on the models. See Appendix H.

0 − 11 0 − 11 0 − 11

1 0 Primary winding 1 0 Secondary winding 1 0 Tertiary winding

currents

3POR Trip mode (if [Phase matching] = Beta)

⎯ 23 ⎯

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6 F 2 S 0 8 5 7

Setting of ik

ik determines the minimum operation sensitivity of the DIF element. ik is set as a ratio to the CT secondary rated current.

The minimum sensitivity setting ik is determined from the maximum erroneous differential current under normal operating conditions.

Setting of p1, p2 and kp

Percentage restraining factor (% slope)

= (Differential current) / (Through current) = (Differential current) / [{(Incoming current) + (Outgoing current)} /2]

p1 is the percentage restraining factor which defines the DIF restraining characteristic in the small current region. The setting is determined by the sum of:

• CT accuracy error (generally considered as 5%)

• Tap error: Error between maximum/minimum tap and the middle tap when taking the middle

tap of the tap changer as a reference.

• Matching error: The error due to CT mismatch may be small enough to be neglected in the setting.

• Relay calculation error, and others (5%)

The recommended setting is “Sum of above” × 1.5 (margin). p2 is the percentage restraining factor which defines the restraining characteristic in the large

current region. The setting is determined from the maximum erroneous differential current which is generated when a large through fault current flows.

kp is the break point of the dual percentage restraining characteristics. It is set above the maximum operating current level of the transformer between the maximum forced-cooled rated current and the maximum emergency overload current level, as a ratio to the CT secondary rated current.

Setting of k2f

k2f is set to detect the second harmonic content in the inrush current during transformer energization and blocks GRT100 to prevent incorrect operation due to the inrush current. A setting of 15% is suggested if there is no data on the minimum second harmonic content.

Setting of k5f

k5f is set to detect the fifth harmonic content during transformer over-excitation and blocks GRT100 to prevent incorrect operation due to transient over-excitation conditions.

A setting of 30% is suggested if there is no data on the minimum fifth harmonic content.

Setting of k

Kh is the HOC setting and should be set above the estimated maximum inrush current. The recommended setting is more than “Maximum peak value of Inrush current” × kct.

Setting for CT ratio matching

Taking the transformer shown in Figure 2.2.5.1 as an example, the CT ratio matching settings kct1 to kct3

can be calculated as follows. For transformer capacity, take the maximum of the rated

capacites of the three windings.

⎯ 24 ⎯

Page 26

6 F 2 S 0 8 5 7

Calculation steps Primary Secondary Tertiary

(1) Transformer capacity (kVA)

40 × 10 (2) Voltage(kV) 154 66 11 (3) Rated line current(A) 150 350 2100

=(1)/(

3 × (2)) (4) CT ratio 60 120 240 (5) Secondary rated line current(A) =(3)/(4)

2.50 2.92 8.75 (6) CT secondary rating(A) 5 5 5 (7) Setting =(6)/(5) Kct1=2.00 Kct2=1.71 Kct3=0.57

Note: kct1 to kct3 should be set to 2.00 or less. If more, the CT ratio matching of relay input current

may be not stable.

CT1 300/5

Primary 40MVA

154kV

Tertiary

12MVA

11kV

Secondary

40MVA

66kV

CT3 1200/5

CT2 600/5

kct1 kct3

GRT100

kct2

Figure 2.2.5.1 CT Ratio Matching

As explained in Section 2.2.3 for Mathcing of CT Secondary Currents, examples of setting for both α-method and β-method are described as follows:

⎯ 25 ⎯

Page 27

2 3 4

6 F 2 S 0 8 5 7

Setting for phase angle matching

The phase angle difference between line currents on either side of the power transformer are corrected by setting according to the hands of a clock and the transformer connections described in IEC60076-1 as follows:

(When α-method is selected for [Phase matching])

If a winding is star-connected, set 1 (=star) for winding setting yd_p, yd_s, and yd_t. If delta-connected, set 2 (=delta). Next, set the phase angle difference vec_s and vec_t from the primary winding as a lagging angle winding expressed in hours. One hour corresponds to lagging by thirty degrees.

Note: In the case of a zigzag connected winding, set 2 (=delta).

Example: Setting for star/star/delta transformer.

Primary

Secondary

Tertiary

IEC60076-1

yd_p yd_s vec_s yd_t vec_t Y y 0 d 11 1 1 0 2 11

Setting

yd_p: Because the primary winding is star-connected, set 1. yd_s: Because the secondary winding is star-connected, set 1. vec_s: Because the secondary winding is in phase with the primary winding, set 0. yd_t: Because the tertiary winding is delta-connected, set 2. vec_t: Because the tertiary winding lags the primary winding by 330°, set 11.

The settings for the transformer connections described in IEC60076-1 are listed in Table 2.2.5.2.

Note: The following calculation is performed in the relay for phase angle correction.

Table 2.2.5.1 Phase Angle Matching Calculation

O’clock Calculation Remarks

0 1

2 3

4 5

6 7

8 9

10 11

Ia’ = (2Ia − Ib − Ic)/ 3 Ib’ = (2Ib − Ic − Ia)/ 3 Ia’ = (Ia – Ib)/

Ia’ = (Ia − 2Ib + Ic)/ 3 Ib’ = (Ia + Ib − 2Ic)/ 3 Ia’ = (Ic − Ib)/

Ia’ = (2Ic − Ia − Ib)/ 3 Ib’ = (2Ia − Ib − Ic)/ 3 Ia’ = (Ic – Ia)/

Ia’ = (Ib + Ic −2Ia)/ 3 Ib’ = (Ia − 2Ib + Ic)/ 3 Ia’ = (Ib − Ia)/

Ia’ = (2Ib − Ia − Ic)/ 3 Ib’ = (2Ic − Ia − Ib)/ 3 Ia’ = (Ib – Ic)/

Ia’ = (Ia + Ib − 2Ic)/ 3 Ib’ = (Ib + Ic −2Ia)/ 3 Ia’ = (Ia – Ic)/

3 Ib’ = (Ib − Ic)/ 3 Ic’ = (Ic – Ia)/ 3

3 Ib’ = (Ia – Ic)/ 3 Ic’ = (Ib − Ia)/ 3

3 Ib’ = (Ia – Ib)/ 3 Ic’ = (Ib – Ic)/ 3

3 Ib’ = (Ic − Ib)/ 3 Ic’ = (Ia – Ic)/ 3

3 Ib’ = (Ic – Ia)/ 3 Ic’ = (Ia – Ib)/ 3

3 Ib’ = (Ib − Ia)/ 3 Ic’ = (Ic − Ib)/ 3

Ic’ = (2Ic − Ia − Ib)/ 3

Ic’ = (Ib + Ic −2Ia)/ 3

Ic’ = (2Ib − Ia − Ic)/ 3

Ic’ = (Ia + Ib − 2Ic)/ 3

Ic’ = (2Ia − Ib − Ic)/ 3

Ic’ = (Ia − 2Ib + Ic)/ 3

Setting value

⎯ 26 ⎯

Page 28

Table 2.2.5.2 Setting for Phase Angle Matching (for α-method)

(a) Settings for typical connections of 2-windings transformer

Transformer connections described in IEC60076-1 Primary, Secondary (P) (S)

Yy0

Dd0

Yd1

Dy1

Dd2

Dd4

Yd5

Dy5

Yy6

Dd6

Yd7

Dy7

Dd8

Dd10

Yd11

Dy11

Dz10

Note: A 2-windings transformer covers a 3-windings transformer with a stabilizing-winding circuit

for which 2-windings transformer protection relay can be applied.

Settings for phase angle correction Remarks Primary, Secondary, Phase angle Diff.

(yd_p) (yd_s) (vec_s)

1 1 0

2 2 0

1 2 1

2 1 1

2 2 2 P: 1 O’clock

2 2 4 P: 1 O’clock

1 2 5 P: 0 O’clock

2 1 5 P: 7 O’clock

1 1 6 P: 0 O’clock

2 2 6 P: 1 O’clock

1 2 7 P: 0 O’clock

2 1 7 P: 5 O’clock

2 2 8 P: 1 O’clock

2 2 10 P: 1 O’clock

1 2 11 P: 0 O’clock

2 1 11

2 2 10 P: 1 O’clock

Phase angle matching calculation (Table 2.2.5.1)

P: 0 O’clock S: 0 O’clock

P: 1 O’clock S: 1 O’clock

P: 0 O’clock S: 1 O’clock

P: 11 O’clock S: 0 O’clock

S: 3 O’clock

S: 5 O’clock

S: 0 O’clock

S: 6 O’clock

S: 7 O’clock

S: 0 O’clock

S: 9 O’clock

S: 11 O’clock

S: 11 O’clock P: 1 O’clock

S: 0 O’clock

S: 11 O’clock

6 F 2 S 0 8 5 7

⎯ 27 ⎯

Page 29

(b) Settings for typical connections of 3-windings transformer

6 F 2 S 0 8 5 7

Transformer connections described in IEC60076-1 Primary , Secondary, Tertiary (P) (S) (T)

Yy0d1

Yy0d11

Yd1d1

Yd11d11

Dy11d0

Dy1d0

Dd0d0

Yy0y0

Settings for phase angle correction Primary, Secondary, PA Diff., Tertiary, PA Diff.

(yd_p) (yd_s) (vec_s) (yd_t) (vec_t)

1 1 0 2 1

1 1 0 2 11

1 2 1 2 1

1 2 11 2 11

2 1 11 2 0

2 1 1 2 0

2 2 0 2 0

1 1 0 1 0

Remarks Phase angle matching calculation (Table

2.2.5.1)

P: 0 O’clock S: 0 O’clock T: 1 O’clock

P: 0 O’clock S: 0 O’clock T: 11 O’clock

P: 0 O’clock S: 1 O’clock T: 1 O’clock

P: 0 O’clock S: 11 O’clock T: 11 O’clock

P: 1 O’clock S: 0 O’clock T: 1 O’clock

P: 11 O’clock S: 0 O’clock T: 11 O’clock

P: 1 O’clock S: 1 O’clock T: 1 O’clock

P: 0 O’clock S: 0 O’clock T: 0 O’clock

Note: Dotted line: Reference phase

Reference phase for phase angle matching The phase of a star-connected winding side is used as the reference phase for phase angle

matching.

Yd: primary Dy: secondary Yy: primary

Dd: the reference vector leads the A phase of the primary side by 30°. Phase rotation The relationship between each terminal current vector of a transformer, which depends on the

transformer connection and the connection between the transformer and the power system, must be checked. The phase displacement of a delta-connected side may not be determined only by the transformer connection described in IEC60076. Table 2.2.5.3 shows an example illustrating the connection of a transformer and power system and their current vectors when a Yd1 type transformer is connected to the power system with both clockwise and anticlockwise phase rotation. In this case, the setting for phase angle correction is not corresponding to that of Table

2.2.5.1.

⎯ 28 ⎯

Page 30

−

6 F 2 S 0 8 5 7

Table 2.2.5.3 Transformer Connection and Current Vector

Connection between Yd1 Transformer and Power system

Each winding connection and Incoming/Outgoing current

Incoming current vector and Outgoing current vector

Delta-side connected with 30° lagging Delta-side connected with 30° leading

Primary

I1a

a b c

Transformer

U V W

Transformer

Yd1

Secondary

2a’=I2a

2b’=I2b

2c’=I2c

Primary

a b c

Transformer

U V W

Transformer

Yd1

I2c I I

Secondary

2a’=I2a

2b’=I2b

2c’=I2c

Incoming

Current

2a’=I2a

2b’=I2b

Outgoing

Current

2c’=I2c

Incoming

Current

2b’=I2b

I1b

I2b

−

Outgoing

Current

2c’=I2c

30°

2a’=I2a

Setting Yd_p=1, yd_s=2, vec_s=1 (Same as Yd1) Yd_p=1, yd_s=2, vec_s=11 (same as Yd11)

Auto-transformer (with internal delta-winding) Set Yy0. Zigzag connected transformer Set yd_p, yd_s and vec_s to 2 (=delta) for zigzag connected side. Zero-sequence current is

canceled. When three-winding model (model 200 series) applied to two-winding transformer: Keep the settings of “yd_t” and “vec_t” to the default setting values. One-and-a-half breaker system When applied to one-and-a-half breaker system, note the DIFT and REF setting as shown in Table

2.2.5.4.

Table 2.2.5.4 Example of DIFT and REF Setting

Setting DIFT 1REF 2REF

Yd11

One-and-a-half breaker system

Yd11

Yy0d11

Yd11 yd_p=1

yd_s=2

vec_s=11

Yy0d11

yd_p=1 yd_s=1

vec_s=0

yd_t=2

vec_s=11

Yy0d11

yd_p=1 yd_s=1

vec_s=0

yd_t=2

vec_s=11

1I0 --

2Io --

1I0 1I0

⎯ 29 ⎯

Page 31

6 F 2 S 0 8 5 7

(When β-method is selected for [Phase matching])

The phase angle differences between line currents on each side of the power transformer are corrected by setting according to the hands of a clock as follows:

Rule 1: If all the windings are star-connected, then take one of the windings as a reference winding and set

1 (= one o’clock) for it. For other winding(s), set the phase angle difference from the reference winding by the expression of the leading angle. One hour corresponds to leading by thirty degrees.

Example 1 If the setting winding leads the reference winding by 60°, set 3 (= three o’clock). Example 2 If the setting winding is in phase with the reference winding, set 1 (= one

o’clock). Example 3 If the setting winding lags the reference winding by 60° (that is leading by 300°), set 11 (= eleven o’clock). Rule 2: If any of the windings are delta-connected, take one of the delta-connected winding(s) as a

reference winding and set 0 (= noon) for it. For other star- or delta-connected winding(s), set according to the Rule 1 mentioned above.

Example 1 If the setting winding leads the reference winding by 60°, set 2 (= two o’clock). Example 2 If the setting winding is in phase with the reference winding, set 0 (= noon). Example 3 If the setting winding lags the reference winding by 60° (that is leading by 300°),

set 10 (ten o’clock). The settings for the two-winding transformer connections described in IEC60076-1 are listed in

Table 2.2.5.5. Three-winding transformers are also set according to the above mentioned rules. Example 4 Setting for star/star/delta transformer.

Setting (d1 / d2 / d3) Primary (d1) 11

Primary

Secondary

Tertiary

Secondary (d2) 11 Tertiary (d3) 0

⎯ 30 ⎯

Page 32

6 7 8 9 10 11 Ia

Note: The following calculation is performed in the relay for phase angle correction.

Setting Calculation Remarks

0 Ia = Ia 1

2 3

4 Ia = Ib 5

6 7

8 Ia = Ic 9

10 11

Ia = (Ia – Ic)/ Ia = −Ic

Ia = (−Ic + Ib)/

Ia = (Ib – Ia)/ Ia = −Ia

Ia = (−Ia + Ic)/

Ia = (Ic – Ib)/ Ia = −Ib

Ia = (Ia – Ib)/

Setting value

6 F 2 S 0 8 5 7

⎯ 31 ⎯

Page 33

Table 2.2.5.5 Setting for Phase Angle Matching (for β-method)

(a) Settings for typical connections of 2-windings transformer

Transformer connections described in IEC60076-1

Settings for phase angle correction Remarks Primary , Secondary

6 F 2 S 0 8 5 7

(d1) (d2)

Yy0

1 , 1

Dd0

Yd1

Dy1

Dd2

Dd4

Yd5

Dy5

Yy6

0 , 0

1 , 0

0 , 11

0 , 10 or 2 , 0 0 , 8 or 4 , 0 5 , 0

0 , 7

1 , 7

Based on primary winding. Based on secondary winding. Based on primary winding. Based on secondary winding.

Based on primary winding.

Dd6

Yd7

Dy7

Dd8

Dd10

Yd11

Dy11

Note: A 2-windings transformer covers a 3-windings transformer with a stabilizing-winding circuit

or 7 , 1 0 , 6 or 6 , 0 7 , 0

0 , 5

0 , 4 or 8 , 0 0 , 2 or 10 , 0 11 , 0

0 , 1

Based on secondary winding.

Based on primary winding. Based on secondary winding. Based on primary winding. Based on secondary winding.

for which 2-windings transformer protection relay can be applied.

⎯ 32 ⎯

Page 34

(b) Settings for typical connections of 3-windings transformer

6 F 2 S 0 8 5 7

Transformer connections described in IEC60076-1

Yy0d1

Yy0d11

Yd1d1

Yd11d11

Dy11d0

Dy1d0

Dd0d0

Yy0y0

Settings for phase angle correction

Primary, Secondary, Tertiary

(d1) (d2) (d3)

1 , 1 , 0

11 , 11 , 0

1 , 0 , 0

11 , 0 , 0

0 , 1 , 0

0 , 11 , 0

0 , 0 , 0

1 , 1 , 1

Remarks

Note :

1. If all the windings are star-connected, then take one of the windings as a reference winding

and set 1 (= one hour) for it.

2. If any of the windings are delta-connected, take one of the delta-connected winding(s) as a

reference winding and set 0 for it.

⎯ 33 ⎯

Page 35

2.3 Restricted Earth Fault Protection

Restricted earth fault protection (REF) is a zero-phase current differential scheme applied to a star-connected winding whose neutral is earthed directly or through a low impedance. It gives highly sensitive protection for internal earth faults.

REF employs a low impedance current differential scheme which detects the differential current between the zero-sequence current I current I

in the neutral conductor as shown in Figure 2.3.1.

Figure 2.3.1 Restricted Earth Fault Protection

6 F 2 S 0 8 5 7

derived from the three-phase line currents and the neutral

Ia+Ib+Ic

REF

REF and the overall differential protection DIFT use the three-phase line currents in common. GRT100 has two or three REF elements depending on the model, providing separate protection

for all star-connected and neutral-earthed windings. The elements have the same percentage restraining characteristics and are stable for all faults

outside the protected zone. Figure 2.3.2 shows the block diagram of the REF element which is composed of REF_DIF and

REF_DEF. The REF_DIF has a percentage restraining characteristic while the REF_DEF provides a directional check feature to discriminate between internal and external faults. When the REF_DEF is “ON”, the REF_DEF element is used. The REF_DEF element provides additional security against incorrect operation of the REF element in the event of saturation of the neutral CT. The REF_DEF is blocked when the maximum phase current exceeds 2 × kct × (Rated current of neutral CT), since the REF element is used for earth fault protection of transformer winding. For details, see Section 2.10.3. In case of terminal current larger than that, the DIFT element provides tripping. The REF_DEF can be disabled by setting the scheme switch [REF_DEF] to “OFF”.

REF_DIF

REF_DEF

internal fau lt d e tec t ion

Ires≦ 2.0× Max_kct

≥1

REF

[REF_DEF]

OFF

Figure 2.3.2 Block Diagram of REF

Figure 2.3.3 shows the scheme logic of the restricted earth fault protection when three REF elements are applied. Each REF element can perform instantaneous or time-delayed tripping of up to five breakers. Any of the five breaker tripping signals 1REF-1 to 3REF-5 are enabled or disabled by the scheme switch [1REF1] to [3REF5] settings.

Note: Models 203 and 204 are not provided with 1REF-4, 1REF5, 2REF-4, 2REF-5, 3REF-4 and

⎯ 34 ⎯

Page 36

[

]

[

]

[

]

[

]

[

]

6 F 2 S 0 8 5 7

3REF-5.

1REF

2REF

T1REF

t 0

0.00 - 10.00s

Same as above

1REF1

“ON”

1REF2

“ON”

1REF3

“ON”

1REF4

“ON”

1REF5

“ON”

1REF-1

1REF-2

1REF-3

1REF-4

1REF-5

≥1

2REF-1 2REF-2 2REF-3 2REF-4 2REF-5

≥1

332

1REF TRIP

333

2REF TRIP

≥1

3REF-1 3REF-2 3REF-3 3REF-4 3REF-5

334

3REF TRIP

3REF

Same as above

Note: Models 203 and 204 are not provided with 1REF-4, 1REF-5, 2REF-4, 2REF-5, 3REF-4 and

3REF-5.

Figure 2.3.3 Scheme Logic of Restricted Earth Fault Protection

Appendix L shows applications of the three REF elements to various types of transformers. When protecting a two- or three-winding transformer, 1REF, 2REF and 3REF elements should be applied to the primary (or high-voltage) winding, secondary (or medium-voltage) winding and tertiary (or low-voltage) winding respectively. This is also valid for auto-transformer protection but the application must comply with Appendix L.

In the application to auto-transformers, one REF element may introduce two or three line currents and one neutral current as shown in Appendix L. 1REF to 3REF elements recognize the number of the line currents according to the scheme switch setting of [1REF] to [3REF].

⎯ 35 ⎯

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6 F 2 S 0 8 5 7

Setting

The following shows the setting elements for the restricted earth fault protection and their setting ranges.

Element Range Step Default Remarks

1REF 1ik 1kct1 1kct2 1kct3 1p2 1kp

2REF 2ik 2kct1 2kct2 2kct3 2p2 2kp

3REF 3ik 3kct1 3kct2

0.05 − 0.50(*)

1.00 − 50.00

1.00 − 50.00 50 − 100%

0.50 − 2.00(*)

0.05 − 0.50(*)

1.00 − 50.00

1.00 − 50.00 50 − 100%

0.50 − 2.00(*)

0.05 − 0.50(*)

1.00 − 50.00

0.01 0.50 Minimum operating current

0.01 1.00

0.01 1.00 CT ratio matching

0.01 1.00 1% 100% % slope of DF2

0.01 1.00 DF2 restraining current section of large current characteristic

0.01 0.50 Minimum operating current

0.01 1.00

0.01 1.00 CT ratio matching

0.01 1.00

1% 100% % slope of DF2

0.01 1.00 DF2 restraining current section of large current characteristic

0.01 0.50 Minimum operating current

0.01 1.00

0.01 1.00 CT ratio matching

3kct3 3p2 3kp

T1REF T2REF T3REF Scheme switch [1REF1] to [1REF5] [2REF1] to [2REF5] [3REF1] to [3REF5] [1REF] to [3REF] [REF_DEF]

(*): Multiplier of secondary rated current (**): Default settings are dependent on the models. See Appendix H.

1.00 − 50.00 50 − 100%

0.50 − 2.00(*)

0.00 − 10.00s

Off/On Off/On Off/On 1Io/2Io/3Io Off/On

0.01 1.00

1% 100% % slope of DF2

0.01 1.00 DF2 restraining current section of large current characteristic

0.01s 0.00s

0.01s 0.00s Delayed tripping

0.01s 0.00s

(**) (**) (**) 1Io Off

Enable or disable to output tripping signal

Number of line currents input to 1REF, 2REF and 3REF elements

Setting of ik (1ik, 2ik and 3ik)

1ik, 2ik and 3ik are minimum operating current settings and are set as a ratio to the line CT secondary rated current. ik is determined from the maximum erroneous zero sequence differential current under normal operating conditions. A typical setting would be between 10% and 50%.

⎯ 36 ⎯

Page 38

6 F 2 S 0 8 5 7

Setting of kct (1kct1-1kct3, 2kct1-2kct3 and 3kct1-3kct3)

CT ratio matching is performed between the line CT(s) and the neutral CT by setting 1kct1-1kct3 for 1REF element, 2kct1-2kct3 for 2REF element and 3kct1-3kct3 for 3REF element. The settings are obtained as a ratio of the line CTs ratio to the neutral CT ratio and the line CTs have the notations shown in Appendix L according to 1REF to 3REF applications.

For example, the settings of 1kct1, 1kct2, 2kct1 and 2kct2 are calculated; 1kct1 = (CT ratio of line CT 1ct-1)/(CT ratio of neutral CT 1nCT) 1kct2 = (CT ratio of line CT 1ct-2)/(CT ratio of neutral CT 1nCT) 2kct1 = (CT ratio of line CT 2ct-1)/(CT ratio of neutral CT 2nCT) 2kct2 = (CT ratio of line CT 2ct-2)/(CT ratio of neutral CT 2nCT) where, CT ratio = (primary rated current)/(secondary rated current).

Setting of scheme switch [1REF] to [3REF]

[1REF] to [3REF] are set to "1I0", "2I0" or "3I0" when they introduce one, two or three line currents respectively.

Setting of scheme switch [REF_DEF]

The function of REF_DEF is set to “On/Off” by setting.

⎯ 37 ⎯

Page 39

2.4 Overcurrent Protection

GRT100 provides definite time and inverse time overcurrent elements for both phase faults and earth faults, separately for each transformer winding. Three phase currents from each set of line CTs are used for the phase fault protection elements, while the earth fault protection is based on the neutral CT input.These elements can be used selectively depending on the requirements of the particular application, but the following points should be noted:

• In the case of large power transformers, overcurrent protection is usually employed only as back-up protection for terminal faults, and for uncleared LV system faults. In such cases, the overcurrent elements can be applied either on one or both sides of the transformer as required.

• Coverage of internal transformer faults is generally limited.

• It is common practice to apply IDMTL phase and earth fault overcurrent protection as

back-up for the LV system. Current and time settings must be arranged to grade with downstream relays and fuses. The phase fault current setting must also be set to exceed the maximum overload current.

• High-set instantaneous overcurrent protection can be applied on the primary side to provide back-up protection for terminal faults. The current setting must be higher than the maximum through-fault current to ensure that the element does not operate for faults on the LV side.

6 F 2 S 0 8 5 7

One of the following IEC-standard-compliant inverse time characteristics or one long time inverse characteristic is available for the inverse current protection.

• standard inverse IEC 60255-3

• very inverse IEC 60255-3

• extremely inverse IEC 60255-3

Up to three definite time elements (1OC to 3OC) and inverse time elements (1OCI to 3OCI) input three phase currents from line CTs in the transformer windings.

Up to three definite time elements (1EF to 3EF) and inverse time elements (1EFI to 3EFI) input neutral currents from CTs in the neutral circuit.

Figure 2.4.1 and Figure 2.4.2 show the scheme logic of overcurrent protection. Each element can perform time-delayed tripping of up to five breakers. The breaker tripping signals are blocked by the scheme switch settings.

The number of overcurrent elements applied depends on the relay models.

⎯ 38 ⎯

Page 40

[

]

[

]

[

]

[

]

[

]

[

]

[

]

[

]

[

]

[

]

6 F 2 S 0 8 5 7

1OC

1OCI

A B C

47 48 49

50 51 52

≥1

370

0.00 - 10.00s

225

T1OC

t 0

1OC1

1OC2

1OC3

1OC4

1OC5

1OCI1

1OC-1

1OC-2

1OC-3

1OC-4

1OC-5

≥1

1OCI-1

335

1OC TRIP

1OCI2

1OCI3

1OCI4

1OCI5

Note: 2OC and 3OC provide the same logic as 1OC. 2OCI and 3OCI provide the same logic as 1OCI. Models 203 and 204 are not provided with 1OC-4, 1OC-5, 2OC-4, 2OC-5, 3OC-4, 3OC-5,

1OCI-4, 1OCI-5, 2OCI-4, 2OCI-5, 3OCI-4 and 3OCI-5.

1OCI-2

1OCI-3

1OCI-4

1OCI-5

≥1

339

1OIC TRIP

Figure 2.4.1 Scheme Logic of the Overcurrent Protection

⎯ 39 ⎯

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[

]

[

]

[

]

[

]

[

]

[

]

[

]

[

]

[

]

[

]

6 F 2 S 0 8 5 7

1EF

1EFI

T1EF

t 0

0.00 - 10.00s

1EF1

1EF2

1EF3

1EF4

1EF5

1EFI1

≥1

1EF-1

1EF-2

1EF-3

1EF-4

1EF-5

343

1EFI-1

1EF TRIP

1EFI2

1EFI3

1EFI4

1EFI5

Note: 2EF and 3EF provide the same logic as 1EF. 2EFI and 3EFI provide the same logic as 1EFI. Models 203 and 204 are not provided with 1EF-4, 1EF-5, 2EF-4, 2EF-5, 3EF-4, 3EF-5, 1EFI-4,

1EFI-5, 2EFI-4, 2EFI-5, 3EFI-4 and 3EFI-5.

1EFI-3

1EFI-4

1EFI-5

≥1

1EFI-2

346

1EFI TRIP

Figure 2.4.2 Scheme Logic of the Overcurrent Protection for Earth Faults

⎯ 40 ⎯

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6 F 2 S 0 8 5 7

Setting

The following shows the setting elements for the overcurrent protection and their setting ranges.

Element Range Step Default Remarks

1OC 2OC 3OC T1OC T2OC T3OC 1OCI 2OCI 3OCI T1OCI T2OCI T3OCI 1EF 2EF 3EF T1EF

0.10 − 20.0(*)

0.00 − 10.00s

0.10 − 5.00(*)

0.05 − 1.00

0.10 − 20.00(*)

0.00 − 10.00s

0.01 2.00 Definite time overcurrent (line)

0.01s 1.00s Delayed tripping for 1OC

0.01s 1.00s Delayed tripping for 2OC

0.01s 1.00s Delayed tripping for 3OC

0.01 1.00 Inverse time overcurrent (line)

0.01 1.00 Time multiplier setting for 1OCI

0.01 1.00 Time multiplier setting for 2OCI

0.01 1.00 Time multiplier setting for 3OCI

0.01 2.00 Definite time overcurrent (neutral)

0.01s 1.00s Delayed tripping for 1EF T2EF T3EF 1EFI 2EFI 3EFI T1EFI T2EFI T3EFI Scheme switch M1OCI to M3OCI M1EFI to M3EFI Scheme switch [1OC1] to [3OC5] [1OCI1] to [3OCI5] [1EF1] to [3EF5] [1EFI1] to [3EFI5]

0.00 − 10.00s

0.10 − 5.00(*)

0.05 − 1.00

Long-Std-Very-Ext Long-Std-Very-Ext Off/On (**) Enable or disable tripping by

0.01s 1.00s Delayed tripping for 2EF

0.01s 1.00s Delayed tripping for 3EF

0.01 1.00 Inverse time overcurrent (neutral)

0.01 1.00 Time multiplier setting for 1EFI

0.01 1.00 Time multiplier setting for 2EFI

0.01 1.00 Time multiplier setting for 3EFI

Std Std

Inverse time characteristic selection of OCI elements EFI elements

OC elements OCI elements EF elements EFI elements

(*) : Multiplier of CT secondary rated current. (**) : Default settings are dependent on the models. See Appendix H.

The overcurrent elements use the same three-phase line currents and neutral current as the

⎯ 41 ⎯

Page 43

6 F 2 S 0 8 5 7

differential protection and the restricted earth fault protection. When choosing settings, the following relationships between the overcurrent elements and the connected windings must be taken into account.

1OC, 1OCI : Primary (high-voltage) winding 2OC, 2OCI : Secondary (medium-voltage) winding 3OC, 3OCI : Tertiary (low-voltage) winding 1EF, 1EFI : 1REF applied neutral circuit 2EF, 2EFI : 2REF applied neutral circuit 3EF, 3EFI : 3REF applied neutral circuit

⎯ 42 ⎯

Page 44

[

]

[THR2]

[THR4]

[

]

2.5 Thermal Overload Protection

The thermal overload protection is applied to protect transformers from electrical thermal damage. A-phase current is used to detect the thermal overload of a transformer. The characteristics are exponential functions according to the IEC 60255-8 standard and take into account the I due to the particular operational current and the simultaneous cooling due to the coolant. In this way the tripping time during an overload condition takes the pre-load into consideration. An alarm stage can be set to operate before reaching the tripping condition.

Figure 2.5.1 shows the scheme logic of the thermal overcurrent protection. THR tripping output can be given to up to five breakers. Any of the five breaker tripping signals THR-1 to THR-5 can be blocked by the scheme switch [THR1] to [THR5] settings. Alarming signal THR-A can be blocked by the scheme switch [THRA] setting.

THR

THR1

“ON”

6 F 2 S 0 8 5 7

R losses

THR-1

THR-2

“ON”

[THR3]

“ON”

[THR5]

“ON”

THRA

“ON”

Note: Models 203 and 204 are not provided with THR- 4 and THR-5.

248

THR-3

THR-4

THR-5 &

THR-A

≥1

351

THR TRIP

Figure 2.5.1 Scheme Logic of Thermal Overload Protection

Setting

The following shows the setting elements for the thermal overload protection and their setting ranges.

Element Range Step Default Remarks

τ 0.5 − 500.0min k IB

0.10 − 4.00

0.50 − 2.50(*1)

0.1min 60.0min Thermal time constant

0.01 1.30 Constant

0.01 1.00 Basic current Ip TA Scheme switch

THR1 to THR5 THRA

0.00 − 1.00(*1) 0 − 10min

Off/On Off/On

0.01 0.00 Pre-specified load current

1min 10min Time for alarm (before trip) (*3)

(*2) On

Enable or disable Trip Alarm

(∗1): Multiplier of CT secondary rated current (*2): Default settings are dependent on the models. See Appendix H.

(*3): Alarming time = THR trip time (operating time) – TA (setting time)

Note: Ip sets a minimum level of previous load current to be used by the thermal element, and is

typically used when testing the element. For the majority of applications, Ip should be set to zero, in which case the previous load current, Ip, is calculated internally by the thermal model, providing memory of conditions occurring before an overload.

⎯ 43 ⎯

Page 45

[

]

[

]

[

]

[

]

[

]

[

]

[

2.6 Frequency Protection

GRT100 provides underfrequency or overfrequency protection and/or alarms for load shedding or for detecting such an overfrequency condition caused by disconnecting load from a particular generation location.

The frequency element FRQ comprises two frequency elements 81-1 and 81-2, the former is used for tripping and the latter for alarms.

Figure 2.6.1 shows the scheme logic of the frequency protection. The tripping element 81-1 outputs underfrequency and overfrequency trip signals L1 and H1. Either underfrequency or overfrequency protection is selected by setting the scheme switch [FRQ-UF1] to “ON” or “OFF”.

The alarm element 81-2 outputs underfrequency and overfrequency alarm signals L2 and H2. Either underfrequency or overfrequency alarms are selected by setting the scheme switch [FRQ-UF2] to “ON” or “OFF”.

Frequency protection can perform time-delayed tripping of up to five breakers. Any of the breaker tripping signals FRQ-1 to FRQ-5 can be blocked by the scheme switch [FRQ1] to [FRQ5] settings.

Note: Models 203 and 204 are not provided with FRQ-4 and FRQ-5.

6 F 2 S 0 8 5 7

81-1 81-2

[FRQ-UF1]

FRQ-UF2]

Alarm signal FRQ-A can be blocked by the scheme switch [FRQA] setting. Frequency protection is blocked under the condition that the system voltage is lower than the

setting of the undervoltage element UV.

TFRQL

0 t

119

0.00 - 60.00s

TFRQH

0 t

0.00 - 60.00s

TFRQA

≥1

0.00 - 60.00s

≥1

FRQ1

FRQ2

FRQ3

FRQ4

FRQ5

FRQA

FRQ-1

FRQ-2

FRQ-3

FRQ-4

FRQ-5

FRQ-UF1]

≥1

FRQ-UF2]

OFF

353

FRQ-UF TRIP

354

FRQ-OF TRIP

249

FRQ TRIP

355

FRQ-UF ALARM

356

FRQ-OF ALARM

257

FRQ A

Note: Models 203 and 204 are not provided with FRQ-4 and FRQ-5.

Figure 2.6.1 Scheme Logic of Frequency Protection

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6 F 2 S 0 8 5 7

Setting

The following shows the setting elements for the frequency protection and their setting ranges.

Element Range Step Default Remarks

81-1 (L1, H1)

81-2 (L2, H2)

UV TFRQL

TFRQH

TFRQA Scheme switch [FRQ-UF1] [FRQ-UF2] [FRQ1] to [FRQ5] [FRQA]

(*) : Frequency values shown in parentheses are for the case of 60Hz rating. Other frequency values

are shown for the case of 50Hz rating.

(**): Default settings are dependent on the models. See Appendix H.

45.00 − 55.00Hz (54.00 − 66.00Hz

40 − 100V

0.00 − 60.00s

Off/On Off/On Off/On Off/On

0.01Hz

0.01Hz 1V 40V Undervoltage block

0.01s 10.00s Underfrequency trip time

0.01s 10.00s Overfrequency trip time

0.01s 10.00s Alarm time delay

49.00Hz

59.00Hz) (*)

48.00Hz

58.00Hz)

On On (**) On

Trip

Alarms

delay

Enable or disable Trip Alarm Trip Alarm

⎯ 45 ⎯

Page 47

2.7 Overexcitation Protection

Overexcitation protection is applied to protect transformers from overvoltage and overfluxing conditions.

Any single phase-to-phase connected voltage is used to detect overexcitation. Trip and alarm characteristics, which are based on a measurement of the voltage/frequency ratio, are provided.

Figure 2.7.1 shows the scheme logic of overexcitation protection. Overexcitation element V/F responds to voltage/frequency and outputs three signals. Signal T has an inverse time characteristic. Signals H and A have high-set and low-set definite time characteristics respectively. Signal T and signal H with a delayed pick-up timer TVFH are used for tripping. Signal A is used for alarm with a delayed pick-up timer TVFA.

The V/F element has a reset feature with definite time reset. The reset time RT is set to match the cooling characteristic that is the time for the protected transformer to reach a normal temperature after releasing the overexitation condition.

6 F 2 S 0 8 5 7

V/F

TVFH

1 - 600s

TVFA

1 - 600s

V/F-T

≥1

TV/F-H

[V/F1]

[V/F2]

[V/F3]

[V/F4]

[V/F5]

[V/FA]

242

V/F-1

V/F-2

V/F-3

V/F-4

V/F-5

≥1

V/F-A

V/F-T

TV/F-H

& &

362

363

350

V/F-L TRIP

V/F-H TRIP

V/F TP

Note: Models 203 and 204 are not provided with V/F-4 and V/F-5.

Figure 2.7.1 Scheme Logic of Overexcitation Protection

Overexcitation protection can trip up to five breakers. Any of the breaker tripping signals V/F-1 to V/F-5 can be blocked by the scheme switch [V/F1] to [V/F5] settings.

Note: Models 203 and 204 are not provided with V/F-4 and V/F-5.

Alarm signal V/F-A can be blocked by the scheme switch [V/FA] setting.

⎯ 46 ⎯

Page 48

)

6 F 2 S 0 8 5 7

Setting

The following shows the setting elements for the overexcitation protection and their setting ranges.

Element Range Step Default Remarks

V A L H LT

TVFH

TVFA

Scheme switch [V/F1] to [V/F5] [V/FA]

(∗): Multiplier of (rated voltage) / (rated frequency) (**): Refer to Appendix H for default setting.

100.0 − 120.0V

1.03 − 1.30

1.05 − 1.30

1.10 − 1.40 1 − 600s

1 − 600s

60 − 3600s

1 − 600s

Off/On Off/On

0.1V 100.0V Transformer rated voltage / VT ratio

(∗)

0.01 1.03 Alarm

0.01 1.05 Low level

0.01 1.40 High level 1s 600s Operation time at low level

1s 1s Operation time at high level

1s 250s Reset time after removing

1s 10s Operating time at high level setting

1s 10s Alarm time

(**) On

(Inverse time curve)

overexcitation condition

(Definite time delay)

Enable or disable tripping Enable or disable alarm

V/Hz

: Alarm level

H: High level (definite time tripping) L: Low level

HT: Operating time at high level L T: Operating time at low level TVFH: Operating time at high level setting TVFA : Alar m time

Withstand curve for transformer overexcitation

ick up level

TVFA

TVFH

Figure 2.7.2 Setting Points

sec

(log T)

⎯ 47 ⎯

Page 49

2.8 Trip by External Devices

Up to four binary signals EXT. MECHANICAL TRIP1 to EXT. MECHANICAL TRIP4 can be used for tripping external devices. Figure 2.8.1 shows the scheme logic for the signal EXT_MEC.TP1. The signal can trip up to five breakers. Any of the tripping signals EXT_MEC.TP1-1 to EXT_MEC.TP4-5 can be blocked by the scheme switches [M.T1-1] to [M.T1-5] setting.

Note: Models 203 and 204 are not provided with EXT_MEC.TP1-4 and EXT_MEC.TP1-5, and

[M.T1-4] and [M.T1-5].

The other binary signals have the same scheme logic.

6 F 2 S 0 8 5 7

EXT. MECHANICAL TRIP1

1536

[M.T1-1]

[M.T1-2]

[M.T1-3]

[M.T1-4]

[M.T1-5]

EXT_MEC.TP1-1

EXT_MEC.TP1-2

EXT_MEC.TP1-3

EXT_MEC.TP1-4

EXT_MEC.TP1-5

357

≥1

MEC.TRIP1

Figure 2.8.1 Scheme Logic of Trip by External Device

Setting

The following shows the setting elements for tripping by external devices and their setting ranges.

Element Range Step Default Remarks

Scheme switch EXT_MEC.TP1-1 to -5 EXT_MEC.TP2-1 to -5

Off/On

(*)

Enable or disable tripping

EXT_MEC.TP3-1 to -5 EXT_MEC.TP4-1 to -5

(*): Default settings are dependent on the model. See Appendix H.

⎯ 48 ⎯

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2.9 Tripping Output

Figure 2.9.1 shows the tripping logic. Each protection can output five tripping signals to enable tripping for five breakers. The tripping signals are set according to the number of breakers to be tripped and drive the heavy duty, high-speed tripping output relays TRIP-1 to TRIP-5.

Note: Models 203 and 204 are not provided with TRIP-4 and TRIP-5.

When the scheme switch [L/O] is set to “ON”, tripping signals can be locked and reset with the 〔RESET〕key on the front panel. When the switch is set to “OFF”, they are reset automatically after clearing the fault.

The tripping output relays reset 200ms after the tripping signal disappears. When [L/O] is set to “OFF”, the tripping circuit must be opened with the auxiliary contact of the breaker prior to reset of the tripping relay to prevent the tripping relay from directly interrupting the tripping current of the breaker.

6 F 2 S 0 8 5 7

⎯ 49 ⎯

Page 51

TRIP-1

DIFT-1

1OC-1 1OCI-1 1REF-1 1EF-1 1EFI-1

2OC-1 2OCI-1 2REF-1 2EF-1 2EFI-1

3OC-1 3OCI-1 3REF-1 3EF-1 3EFI-1

≥1

[L/O]

“ON”

≥1

[RESET]

6 F 2 S 0 8 5 7

Tripping output relay

≥1

F/F

≥1

0 t

0.2s

284

TRIP-1

FRQ-1 V/F-1 THR-1

MECHANICAL TRIP1-1 MECHANICAL TRIP2-1 MECHANICAL TRIP3-1 MECHANICAL TRIP4-1

TRIP-2

Same as TRIP-1

TRIP-3

Same as TRIP-1

TRIP-4

Same as TRIP-1

TRIP-5

Same as TRIP-1

≥1

0 t

0.2s

0 t

0.2s

0 t

0.2s

291

298

305

312

TRIP-2

TRIP-3

TRIP-4

TRIP-5

Figure 2.9.1 Tripping Logic

⎯ 50 ⎯

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2.10 Characteristics of Measuring Elements

2.10.1 Percentage Current Differential Element DIF

The segregated-phase current differential element DIF has dual percentage restraining characteristics. Figure 2.10.1 shows the characteristics of DF1 and DF2 on the differential current (Id) and restraining current (Ir) plane. Id is a vector summation of phase current of all windings

and Ir is a scalar summation of phase current of all windings.

6 F 2 S 0 8 5 7

ik 2

Figure 2.10.1 Current Differential Element

DF1

Id = 2Ir (one-end infeed)

DF2

Characteristic DF1 is expressed by the following equation:

Id ≥ p1 x Ir + (1 −p1/2)ik

where, p1 : slope of DF1

ik : minimum operating current Id and Ir are defined as follows for a three-winding transformer.

= | kct1⋅I1 + kct2⋅I2 + kct3⋅I3 |

=(kct1⋅|I1 |+ kct2⋅|I2 |+ kct3⋅|I3 |)/2

where, kct1 ,kct2 ,kct3 I

,I2 ,I3 : currents of primary, secondary and tertiary winding

: CT ratio matching settings of primary, secondary and tertiary winding

This characteristic has weaker restraint in the small current region and ensures sensitivity to low level faults.

Characteristic DF2 is expressed by the following equation:

Id ≥ p2 x Ir + (p1 −p2)kp + (1 −p1/2)ik

where, p2 : slope of DF2 kp : break point of DF1 characteristic This characteristic has stronger restraint in the large current region and ensures stability against

CT saturation during through faults.

⎯ 51 ⎯

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6 F 2 S 0 8 5 7

2.10.2 High-set Overcurrent Element HOC

High-set overcurrent element HOC is an instantaneous overcurrent characteristic, and is applied in the differential circuit. The characteristic is expressed by the following equation:

Id ≥ kh Id is defined as follows for three-winding transformer.

= | kct1⋅I1 + kct2⋅I2 + kct3⋅I3 |

where, kct1, kct2, kct3: CT ratio matching settings of primary, secondary and tertiary winding HOC is an un-restrained current differential element which can protect a transformer against

damage due to a heavy internal fault, because it has a simple operation principle and high-speed operation. Note that HOC is not immune to transformer inrush currents and therefore cannot be applied with a sensitive setting.

2.10.3 Restricted Earth Fault Element REF

The restricted earth fault element REF is composed of REF_DIF and REF_DEF, as was shown in Figure 2.3.2.

The REF_DIF has dual percentage restraining characteristics. Figure 2.10.2 shows the characteristics on the differential current (Id) and restraining current (Ir) plane. Id is the differential current between the residual current of each winding and the neutral current and Ir is the restraining current which is the larger of the residual current and the neutral current.

DF2

max-kct⋅ik

Figure 2.10.2 REF_DIF Characteristic

DF1

Characteristic DF1 is expressed by the following equation:

≥ p1⋅Ir + (1-p1) ⋅ik⋅max-kct

where, p1 : slope of DF1 (fixed to 10%) ik : minimum operating current max-kct : CT ratio matching of line CT to neutral CT (when plural line CTs are applied,

maximum kct is employed.)

For the 1REF element, I

and Ir are calculated by the following equations when applied to a circuit

with one neutral CT and three line CTs. (For the REF element application, see Appendix L.)

= |1kct1⋅I1o + 1kct2⋅I2o + 1kct3⋅I3o + IN |

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6 F 2 S 0 8 5 7

Ir = max.( 1kct1⋅|I1a| , 1kct1⋅|I1b| , 1kct1⋅|I1c| , 1kct2⋅|I2a| , 1kct2⋅|I2b| , 1kct2⋅|I2c| ,1kct3⋅|I3a| ,

1kct3⋅|I

| , 1kct3⋅|I3c| , |IN| )

where, I I I

,I2o ,I

,I1b ,I1c ,I2a ,I2b ,I2c ,I3a ,I3b ,I

: residual current of neutral circuit

: residual current of primary, secondary and tertiary winding

: phase current of primary, secondary and tertiary winding

1kct1, 1kct2, 1kct3: CT ratio matching of primary, secondary and tertiary line CT to neutral

CT Characteristic DF2 is expressed by the following equation: I

≥ p2 (Ir−kp)

where p2 : slope of DF2

kp : break point of DF1 characteristic

The characteristic of REF_DEF is composed of a directional characteristic and a non-directional characteristic as shown in Figure 2.10.3 (a) and (b). This characteristic is employed so that the REF is not blocked at one-end infeed current I

90°

(*1)

180

Ik1, ik2: Current sensitivity (0.01pu, 0.025pu fixed) I

: Neutral current of transformer

: Zero sequence current (calculated from Ia, Ib, Ic)

*1: MAX(Ia,Ib,Ic) ≤ 2×MAX(kct1,kct2,kct3)

Ik1

Operating

270°

0°

Ik2

(a) (b)

Figure 2.10.3 REF_DEF Characteristic

The REF_DEF detects an internal fault by checking the direction between transformer neutral current I

and zero-sequence current 3I0 calculated from phase currents Ia, Ib and Ic. The REF_DEF

is blocked when the maximum phase current is larger than 2 times of Max-kct as follows:

Max.(1kct1•I

, ….1kct3•I3c) ≥ I

=Max.(1kct1,1kct2,1kct3)×2

BLK

⎯ 53 ⎯

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6 F 2 S 0 8 5 7

(Example)

Primary CT ratio: 2400/1

kct1=2

I01

1REF

Secondar CT ratio: 3600/1

CT ratio:

1200/1

kct2=3

max-kct = 3 Therefore, REF is blocked at I

=3×2.0=6A (CT secondary)

BLK

If the maximum of phase currents of both primary and secondary windings is 7200A (=6x1200A), the REF is blocked. Reference current: 1200A (Rated current of neutral CT)

2.10.4 Inverse Time Overcurrent Element OCI and EFI

The OCI and EFI elements have one long time inverse characteristic and three inverse time characteristics in conformity with IEC 60255-3 as shown in Figure 2.10.4. One of these characteristics can be selected.

These characteristics are expressed by the following equations and curves.

(s)

200

T=1.0

Long Time Inverse

t = T

(I/Is)−1

120

Standard Inverse

t = T

(I/Is)

0.02

− 1

0.14

Very Inverse

(I/Is)

13.5

− 1

t = T

Extremely Inverse

(I/Is)

− 1

t = T

where,

t : operating time I : fault current Is : current setting T : time multiplier setting

Operating time

100

0.5

0.2

Long-time Inverse

Standard Inverse

Very Inverse

Extremely Invease

0.1 1

Current I (Multiple of setting current)

5 10 20 30

Figure 2.10.4 Characteristics of Inverse Time Overcurrent Element

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2.10.5 Definite Time Overcurrent element OC and EF

The OC and EF elements measure the phase currents and the residual current respectively.

2.10.6 Thermal Overload Element THR

Thermal overload element THR has a characteristic based on thermal replica according to the IEC 60255-8 standard (see Appendix N), which evaluates the phase current (A-phase) of the CT secondary circuits. Figure 2.10.5 shows the characteristic of THR element. The element has trip and alarm stages.

Trip stage:

t = τ x Ln

Alarm stage:

t = τ x Ln

where

− Ip

I2 − (k x IB)

− Ip2) x (1 − TA/τ)

− (k x IB)

t : operating time τ : thermal time constant I : load current kxIB : allowable overload current as specified in IEC 60255-8 (refer to Appendix N)

IB : basic current of transformer (rated current) k : constant (allowable overload current / IB) Ip : prior load current before the overload occurs

TA : time for alarm

(Alarming time = t (operating time) – T

A (setting time)

Ln : natural logarithm

Figure 2.10.6 shows the thermal curve for a range of time constant settings in the cold state when the prior load current Ip is zero.

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larm

Trip

K ⋅ I

Figure 2.10.5 Characteristic of Thermal Overload Element

Thermal Curves (Cold Curve - no

prior load)

10000

1000

100

500

100

50 20

5 2

)

Operate Time (minutes)

0.01

0.1

110

Overload Current (Multiple of kI

Figure 2.10.6 Thermal Curves

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(

)

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2.10.7 Frequency Element FRQ

GRT100 has two elements for trip or alarm. Each element operates either in overfrequency or underfrequency.

2.10.8 Overexcitation Element V/F

The characteristic is based on the ratio of voltage to frequency. The alarm is definite time delayed, while the tripping characteristic is either definite time or inverse time, as shown in Figure 2.10.7.

: Alarm level

H: High level (definite time tripping)

V/Hz

TVFA

Figure 2.10.7 Characteristic of Overexcitation Element

TVFH

L: Low level HT: Operating time at high level LT: Operating time at low level

TVFH: Operating time at high level setting

TVFA : Alar m time

pick up level

sec

(log T)

The inverse time characteristic of V/F is expressed by the following equation.

t =

(V/F) − K

where,

t : operating time V : voltage (any phase-to-phase voltage) F : frequency V/F=(Vm/Fm) / (Vs/Fs)

(Vm: Input voltage, Fm: Input frequency, Vs: Setting of rated voltage, Fs: Rated frequency)

(LT) × L − (HT) × H

K1=

(LT) − (HT)

(LT) × (HT) × (H − L)

(LT) − (HT)

The V/F element has a reset feature with definite time reset (RT). When the V/F falls below the reset threshold, the integral state of the inverse time function is reset to the initial value after the RT time.

Example: V/F=(Vin/Fin)/(V/Fs)=(130/50)/(100/50)=1.3, in case of Vin: Input voltage (130V),

Fin: Input frequency (50Hz), V: Rated voltage (100V), Fs: Rated frequency (50Hz)

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3. Technical Description

3.1 Hardware Description

3.1.1 Outline of Hardware Modules

The case outline of GRT100 is shown in Appendix F. The hardware structures of the models are shown in Figure 3.1.1 and Figure 3.1.2. The front

view shows the equipment without the human machine interface module. The GRT100 consists of the following hardware modules. The human machine interface module

is provided with the front panel.

• Transformer module (VCT)

• Signal processing module (SPM)

• Binary input and output module #1 (IO1 or IO8)

• Binary input and output module #2 (IO2)

6 F 2 S 0 8 5 7

• Binary output module #3 (IO3)

• Human machine interface module (HMI)

Front view without front panel

SPMIO2VCT

IO1 or IO8

Figure 3.1.1 Hardware Structure (Model: 101, 201, 203)

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Figure 3.1.2 Hardware Structure (Model: 102, 202, 204)

IO3VCT

SPM IO1 or

IO2

IO8

The correspondence between each model and module used is as follows:

Models

Module

VCT SPM IO1 IO2 IO3 × IO8 HMI

Note: The VCT and SPM modules are not interchangeable among different models.

101 102 201 202 203 204

× × × × × × × × × × × × × × × × × × × × × ×

× × × × × ×

× ×

The hardware block diagram of the GRT100 using these moduls is shown in Figure 3.1.3.

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(*1)

6 F 2 S 0 8 5 7

Binary I/O Module (IO1 or IO8)

C input

External clock

Transformer Module (VCT)

CT × 8

CT × 12

or or

CT × 15

VT × 1

IRIG-B port

Signal Processing Module (SPM)

nalogue

filter

Human Machine Interface (HMI)

Converter

MPU1

Opt. I/F or Ethernet LAN I/F

DC/DC Converter

Binary input

13 or 12

Binary output (High speed)

5 or 3

Binary I/O Module (IO2)

Binary output

Binary input

RS485

Transceiver

DC supply

Trip command

Remote Setting and Monitoring System

Remote PC

Local Personal Computer

Liquid crystal display 40characters×4lines

LEDs

RS232C

I/F

Operation keys

Monitoring jacks

Binary I/O Module (IO3)

Binary output

(*1) I03: required for Model 102, 202, 204

Figure 3.1.3 Hardware Block Diagram (Models 101, 102, 201, 202, 203 and 204)

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3.1.2 Transformer Module

The transformer module (VCT module) provides isolation between the internal and external circuits through auxiliary transformers and transforms the magnitude of the AC input signals to suit the electronic circuits. The AC input signals are as follows:

• three-phase currents (Ia, Ib and Ic) for each winding

• neutral current (IN) for each winding

• phase-to-phase voltage

Figure 3.1.4 shows a block diagram of the transformer module. There are 8 to 12 auxiliary CTs and 1 auxiliary VT mounted in the transformer module depending on the relay model. (For the correspondence between the relay model and number of AC input signals, see Table 3.2.1.)

The transformer module is also provided with an IRIG-B port. This port collects the serial IRIG-B format data from an external clock for synchronization of the relay calendar clock. The IRIG-B port is isolated from the external circuit by a photo-coupler. A BNC connector is used as the input connector.

External clock

BNC connector

IRIG-B port

Signal processing module

Figure 3.1.4 Transformer Module (e.g. models 101, 102)

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(Op

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3.1.3 Signal Processing Module

The signal processing and communication module (SPM) incorporates a signal processing circuit and a communication control circuit. Figure 3.1.3.1 shows the block diagram.

The signal processing circuit consists of an analog filter, multiplexer, analog to digital (A/D) converter, main processing unit (MPU) and memories (RAM and ROM), and executes all kinds of processing including protection, measurement, recording and display.

The SPM contains a lithium-ion battery, which should be removed at the end-of-life of the product. The nominal backup time of a lithium-ion battery is one year after the shipment from the factory.

The analog filter performs low-pass filtering for the corresponding current and voltage signals. The A/D converter has a resolution of 16 bits and samples input signals at sampling frequencies

of 2400Hz (at 50Hz) and 2880Hz (at 60Hz). The MPU carries out operations for the measuring elements and scheme logic operations for

protection, recording, displaying and signal transmission control. The SPM can be provided with Optical interface or Ethernet LAN interface for serial

communication system.

Analog input

Analog filter

Multiplexer

A/D

converter

MPU

RAM ROM

Optical I/F

tion)

Ethernet LAN

tion)

I/F

Other modules

Link with Serial communication system

Figure 3.1.3.1 Signal Processing Module

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3.1.4 Binary Input and Output Module

There are four types of binary input and output module (IO module): These modules are fitted according to the model (see Section 3.1.1).

3.1.4.1 IO1 and IO8 Module

IO1 and IO8 provide a DC/DC converter, binary inputs and binary outputs for tripping. As shown in Figure 3.1.4.1, the IO1 module incorporates a DC/DC converter, 15 photo-coupler

circuits (BI) for binary input signals and 6 auxiliary relays (TP1 to 5) dedicated to the circuit breaker tripping command.

As shown in Figure 3.1.4.2, the IO8 module incorporates a DC/DC converter, 12 photo-coupler circuits (BI) for binary input signals and 3 auxiliary relays (TP) dedicated to the circuit breaker tripping command. The 12 binary inputs have dedicated positive and negative inputs suitable for double-pole switching.

The nominal input voltage rating of the DC/DC converter is 24V, 48V, 110V/125V or 220V/250V. The normal range of input voltage is −20% to +20%.

The five or three tripping command auxiliary relays are the high-speed operation type and have one normally open output contact.

DC supply

Binary input signals

(+) (−)

15)

(

Line filter

Photo-coupler

DC/DC converter

uxiliary relay

(high speed)

TP-1

TP-2

TP-3

TP-4

TP-5

Tripping command

Figure 3.1.4.1 IO1 Module

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(+)

6 F 2 S 0 8 5 7

DC supply

Binary input signals

(

12)

−)

IO8 module

Line filter

Photo-coupler

Figure 3.1.4.2 IO8 Module

DC/DC converter

uxiliary relay

(high speed)

TP-1

TP-2

TP-3

Tripping command

(× 3)

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3.1.4.2 IO2 Module

As shown in Figure 3.1.4.3, the IO2 module incorporates 3 photo-coupler circuits (BI14-BI16) for binary input signals, 14 auxiliary relays (BO1-BO13 and FAIL) for binary output signals and an RS-485 transceiver.

The auxiliary relay FAIL has one normally closed contact, and operates when a relay failure or abnormality in the DC circuit is detected. BO1 to BO13 each have one normally open contact. BO12 and BO13 are the high-speed operation type.

The RS-485 transceiver is used for the link with the relay setting and monitoring (RSM) system. The external signal is isolated from the relay internal signal.

Binary input signals

Photo-coupler

BI14

BI15

BI16

Figure 3.1.4.3 IO2 Module

uxiliary relay

RS-485 Transceiver

BO1

BO2

FAIL

Binary output signals

Link with RSM system

Link with IEC60870-5-103 Communication system

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3.1.4.3 IO3 Module

The IO3 module is used to increase the number of binary outputs. The IO3 module incorporates 10 auxiliary relays (BO1-BO10) for binary outputs. All auxiliary

relays each have one normally open contact.

IO3 module

uxiliary relay

BO1

BO2

BO9

BO10

Binary output signals

Figure 3.1.4.4 IO3 Module

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3.1.5 Human Machine Interface (HMI) Module

The operator can access the GRT100 via the human machine interface (HMI) module. As shown in Figure 3.1.5, the HMI module has a liquid crystal display (LCD), light emitting diodes (LED), view and reset keys, operation keys, testing jacks and an RS-232C connector on the front panel.

The LCD consists of 40 columns by 4 rows with a backlight and displays record, status and setting data.

There are a total of 8 LED indicators and their signal labels and LED colors are defined as follows:

Label Color Remarks

IN SERVICE Green Lit when relay is in service. TRIP Red Lit when trip command is issued. ALARM Red Lit when failure is detected. TESTING Red

(LED1) Red (LED2) Red

Lit when disabling automatic monitoring function or resetting

the time counting of THR and V/F elements by the scheme switches.

(LED3) Red (LED4) Red

LED1 to LED4 are user-configurable. Once it has started operating, the TRIP LED continues to operate even after the trip command

disappears. Pressing the RESET key resets it. Other LEDs operate as long as a signal is present. The RESET key is ineffective for these LEDs.

The VIEW key starts the LCD indication and switches between windows. The reset key clears the LCD indication and turns off the LCD backlight.

The operation keys are used to display the record, status and setting data on the LCD, input the settings or change the settings.

The monitoring jacks and two pairs of LEDs, A and B, on top of the jacks can be used while the test mode is selected in the LCD window. Signals can be displayed on LED A or LED B by selecting the signal to be observed from the "Signal List" or "Variable Timer List" and setting it in the window and the signals can be transmitted to an oscilloscope via the monitoring jacks. (For the "Signal List" or "Variable Timer List", see Appendix B or C.)

The RS-232C connector is a 9-way D-type connector for serial RS-232C connection. This connector is used for connection with a local personal computer.

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TRANSFORMER PROTECTION

GRT100

101D-21-11

Figure 3.1.5 Front Panel

Operation keys

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3.2 Input and Output Signals

3.2.1 Input Signals

AC input signals

Table 3.2.1 shows the AC input signals necessary for each of the GRT100 models and their respective input terminal numbers. See Appendix G for external connections.

Winding 1, 2 and 3 in the Table correspond to high-voltage or primary, medium-voltage or secondary, and low-voltage or tertiary winding respectively.

6 F 2 S 0 8 5 7

Table 3.2.1 AC Input Signals

Terminal No.

TB1

1-2 3-4 5-6 7-8

9-10 11-12 13-14 15-16 17-18 19-20 21-22 23-24 25-26 27-28

GRT100-101, 102 Terminal

No.

⎯ ⎯ ⎯ ⎯ ⎯

Phase to phase voltage of winding 1

(earth)

TB1

1-2 3-4 5-6 7-8

9-10 11-12 13-14 15-16 17-18 19-20 21-22 23-24 25-26 27-28

GRT100-201, 202, 203, 204

A phase current of winding 1 B phase current of winding 1 C phase current of winding 1 Neutral current of winding 1 A phase current of winding 2 B phase current of winding 2 C phase current of winding 2 Neutral current of winding 2 A phase current of winding 3 B phase current of winding 3 C phase current of winding 3 Neutral current of winding 3

⎯

Phase to phase voltage of winding 1

(earth)

Binary input signals

Table 3.2.2 shows the binary input signals necessary for the GRT100, their driving contact conditions and functions enabled. See Appendix G for external connections.

The binary input circuit of the GRT100 is provided with a logic level inversion function as shown in Figure 3.2.1. Each input circuit has a binary switch BISW which can be used to select either normal or inverted operation. This allows the inputs to be driven either by normally open or normally closed contacts. Where the driving contact meets the contact conditions indicated in Table 3.2.2 then the BISW can be set to “N” (normal). If not, then “I” (inverted) should be selected.

The default setting of the BISW is "N" (normal) for all input signals. Further, all binary input functions are programmable by PLC (Programmable Logic Circuit)

function. If a signal is not required, the function concerned is disabled.

The operating voltage of binary input signal is typical 74V DC at 110V/125V DC rating and 138V DC at 220/250V DC. The minimum operating voltage is 70V DC at 110/125V DC rating and 125V DC at 220/250V DC.

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(

)

(

)

(

)

6 F 2 S 0 8 5 7

Table 3.2.2 Binary Input Signals

(+)

(−)

External Mechanical trip

Signal Names Driving Contact Condition / Function Enabled

External Mechanical trip (EXT_MEC.TP1) External Mechanical trip (EXT_MEC.TP2) External Mechanical trip (EXT_MEC.TP3) External Mechanical trip (EXT_MEC.TP4)

Closed when external device operated. / Initiate trip command from operation of external device. Closed when external device operated. / Initiate trip command from operation of external device. Closed when external device operated. / Initiate trip command from operation of external device. Closed when external device operated. / Initiate trip command from operation of external device.

Indication reset Closed to reset TRIP LED indication. / Reset indication

externally.

Protection block Closed to block the protection. / Block the protection

externally.

Signal for event record Closed when external device operated. / Initiate event record

with external signal.

Signal for event record Closed when external device operated. / Initiate event record

with external signal.

Signal for event record Closed when external device operated. / Initiate event record

with external signal.

GRT100

BI1

BI2

BI3

BISW1 (Norm)

Inv

BISW2 (Norm)

Inv

BISW3 (Norm)

Inv

BI1

BI2

BI3

PLC function

Programmable

logic

Signal No.

BISW∗ (default)

1 2 3 4 5

6 14 15 16

Protection

schemes

3.2.2 Binary Output Signals

The number of output binary signals and their output terminals vary depending on the relay model. See Appendix G for details. For all models, all outputs except the tripping command, signal for command protections and relay failure signal can be configured.

The signals shown in the signal list in Appendix B can be assigned to the output relay individually or in arbitrary combinations. Signals can be combined using either an AND circuit or OR circuit with 6 gates each as shown in Figure 3.2.2. The output circuit can be configured according to the setting menu. Appendix D shows the factory default settings.

A 0.2s delayed drop-off timer can be attached to these assigned signals. The delayed drop-off time is disabled by the scheme switch [BOTD].

The relay failure contact closes when a relay defect or abnormality in the DC power supply circuit is detected.

Figure 3.2.1 Logic Level Inversion

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Signal List

ppendix C

6 GATES

≧

6 GATES

+(ON)

−(OFF)

0.2s

BOTD

t 0

≧1

uxiliary relay

Figure 3.2.2 Configurable Output

3.2.3 PLC (Programmable Logic Controller) Function

GRT100 is provided with a PLC function allowing user-configurable sequence logics on binary signals. The sequence logics with timers, flip-flops, AND, OR, NOT logics, etc. can be produced by using the PC software “PLC tool” and linked to signals corresponding to relay elements or binary circuits.

Configurable binary inputs, binary outputs and LEDs, and the initiation trigger of disturbance record are programmed by the PLC function. Temporary signals are provided for complicated logics or for using a user-configured signal in many logic sequences.

PLC logic is assigned to protection signals by using the PLC editor tool. For PLC tool, refer to PLC tool instruction manual.

Figure 3.2.3 Sample Screen of PLC Tool

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3.3 Automatic Supervision

3.3.1 Basic Concept of Supervision

Though the protection system is in a non-operating state under normal conditions, it is waiting for a power system fault to occur at any time and must operate for the fault without fail. Therefore, the automatic supervision function, which checks the health of the protection system during normal operation by itself, plays an important role. A numerical relay based on microprocessor technology is able to implement such as automatic supervision function. GRT100 implements an automatic supervision function based on the following concept:

• The supervising function should not affect protection performance.

• Perform supervision with no omissions wherever possible.

• When a failure occurs, it should be possible to easily identify the failure location.

Note: Automatic supervision function includes automatic monitor function and automatic test

function. For the terminology, refer to IEC IEV 60448.

3.3.2 Relay Monitoring and Testing

6 F 2 S 0 8 5 7

The relay is supervised with the following items.

AC input imbalance monitoring

The AC current input is monitored such that the following equation is satisfied and the health of the AC input circuit is checked.

Max(|Ia|, |Ib|, |Ic|) − 4 × Min(|Ia|, |Ib|, |Ic|) ≥ k0 where,

Max(|Ia|, |Ib|, |Ic|) = Maximum amplitude among Ia, Ib and Ic Min(|Ia|, |Ib|, |Ic|) = Minimum amplitude among Ia, Ib and Ic k0 = 20% of rated current

A/D accuracy checking

An analogue reference voltage is transmitted to a prescribed channel in the analogue-to-digital (A/D) converter, and it is checked that the data after A/D conversion is within a prescribed range and that the A/D conversion characteristics are correct.

Memory monitoring

The memories are monitored as follows depending on the type of the memory and checked that the memory circuits are healthy:

• Random access memory monitoring: Writes/reads prescribed data and checks the storage function.

• Program memory monitoring: Checks the checksum value of the written data.

• Setting value monitoring: Checks discrepancy between the setting values stored in

duplicate.

Watchdog Timer

A hardware timer which is cleared periodically by software is provided and it is checked that the software is running normally.

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DC Supply monitoring

The secondary voltage level of the built-in DC/DC converter is monitored and checked that the DC voltage is within a prescribed range.

3.3.3 PLC Data and IEC61850 Mapping Data Monitoring

If there is a failure in PLC data and IEC61850 mapping data, the function may be stopped. Therefore, the PLC data and IEC61850 mapping data are monitored and an alarm of "PLC stop" or "MAP stop" is issued if any failure detected.

3.3.4 IEC61850 Communication Monitoring

The sending and receiving functions in the Ethernet LAN communication are monitored. The receiving function is executed by checking GOOSE message receiving status, and the sending function is executed by checking Ping response to the other party. If a failure is detected, an alarm of "GOOSE stop" or "Ping err" is issued.

These functions are disabled by setting the scheme switches [GSECHK] and [PINGCHK].

3.3.5 Failure Alarms

When a failure is detected by the automatic supervision, it is followed with LCD display, LEDs indication, external alarms and event recording. Table 3.3.1 summarizes the supervision items and alarms.

The LCD messages are shown on the "Auto-supervision" screen which is displayed automatically when a failure is detected or displayed by pressing the

are shown on the "Event record" screen by opening the "Record" sub-menu. Those alarms are retained until the failure is recovered. Those alarms can be disabled collectively by setting the scheme switch [AMF] to OFF. The setting

is used to block unnecessary alarms during commissioning test or maintenance. When the Watchdog Timer detects that the software fails to run normally, LCD display and event

recording on the failure cannot be expected. DC supply failure disables the LCD display and event recording on the failure as well. For the discrimination of the two failures mentioned above, refer to Section 6.7.2.

Table 3.3.1 Supervision Items and Alarms

Supervision Item LCD Message

LED "IN SERVICE"

VIEW

LED "ALARM"

key. The event record messages

Ext. alarm Event record

Message

AC input

imbalance monitoring A/D accuracy check A/D err Off On (4) Relay fail CPU, Memory monitoring (1) Watchdog Timer ---- Off On (4) ---DC supply monitoring ---- Off (3) (4) Relay fail PLC data or IEC61850

mapping data monitoring GOOSE message check GOOSE stop

(1) On/Off (2) On (4) CT err

PLC stop or

MAP stop

on on (4) Relay fail-A on on (4) Relay fail-A

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Supervision Item LCD Message LED

"IN SERVICE"

Ping response check Ping err on on (4) Relay fail-A

(1): Diverse messages are provided as expressed with "---fail" in the Table in Section 6.7.2. (2): The LED is on when the scheme switch [SVCNT] is set to "ALM" and off when set to

"ALM & BLK" (refer to Section 3.3.4). (3): Whether the LED is lit o r not depends on the degree of the voltage drops. (4): The binary output relay "FAIL" operates.

LED "ALARM"

Ext. alarm Event record

Message

3.3.6 Trip Blocking

When a failure is detected by the following supervision items, the trip function is blocked as long as the failure exists and restored when the failure is removed.

• A/D accuracy check

• Memory monitoring

• Watchdog Timer

• DC supply monitoring

When a failure is detected by the AC input imbalance monitoring, the scheme switch [SVCNT] setting can be used to determine if both tripping is blocked and an alarm is initiated, or, if only an alarm is initiated.

3.3.7 Setting

The setting elements necessary for the automatic supervision and its setting range are shown in the table below.

Element Range Step Default Remarks

[SVCNT] ALM&BLK / ALM ALM&BLK Alarming and/or blocking [GSECHK] OFF/ON OFF GOOSE check [PINGCHK] OFF/ON OFF Ping response check

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3.4 Recording Function

GRT100 is provided with the following recording functions: Fault recording Event recording Disturbance recording These records are displayed on the LCD of the relay front panel or on the local or remote PC.

3.4.1 Fault Recording

Fault recording is started by a tripping command of the GRT100 or PLC command by user-setting (max. 8) and the following items are recorded for one fault:

Date and time of fault occurrence Operating phase or fault phase Tripping command Tripping mode

6 F 2 S 0 8 5 7

Power system quantities Up to the 8 most-recent faults can be stored as fault records. If a new fault occurs when 8 faults

have been stored, the record of the oldest fault is deleted and the record of the latest fault is then stored.

Date and time of fault occurrence

The time resolution is 1ms using the relay internal clock. To be precise, this is the time at which a tripping command has been initiated, and thus it is

approximately 10 ms after the occurrence of the fault.

Operating phase or fault phase

The operating phase or fault phase can be selected to be displayed following tripping, depending on the requirements of user.

For details, see Section 2.3.1.

Tripping command

The tripping output relay(s) operated is shown in terms of its number (e.g. TP-1: 1, TP-2: 2 etc.).

Tripping mode

This shows the protection scheme that initiated the tripping command.

Power system quantities

The following power system quantities for pre-fault and post-fault are recorded.

- Magnitude and phase angle of phase current of each winding (Ia1, Ib1, I

- Magnitude and phase angle of neutral current of each winding (In1 up to In3)

- Magnitude and phase angle of symmetrical component current of each winding (I11, I21, I01 up to I13, I23, I03)

- Magnitude and phase angle of phase-to-phase voltage (V)

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6 F 2 S 0 8 5 7

- Magnitude of phase differential current (I

da, Idb, Idc

- Magnitude of residual differential current for REF protection (I

)

d01

up to I

d03

)

- Percentage of thermal capacity (THM%)

Phase angles above are expressed taking that of the voltage as a reference phase angle. If the voltage input is not provided, then the positive sequence current of the primary winding is used as a reference phase angle.

3.4.2 Event Recording

The events shown are recorded with a 1 ms resolution time-tag when the status changes. The user can set a maximum of 128 recording items, and their status change mode. The event items can be assigned to a signal number in the signal list. The status change mode is set to “On” (only recording On transitions) or “On/Off”(recording both On and Off transitions) mode by setting. The “On/Off” mode events are specified by “Bi-trigger events” setting. If the “Bi-trigger events” is set to “100”, No.1 to 100 events are “On/Off” mode and No.101 to 128 events are “On” mode.

The name of an event cannot be set on LCD. It can set only by RSM100. Maximum 22 characters can be set and can be viewed on both of the LCD and RSM Setting(view) screen. But the LCD screen of event record displays only 11 characters. Therefore, it is recommended the maximum 11 characters are set.

The elements necessary for event recording and their setting ranges are shown in the table below. The default setting of event record is shown in Appendix H.

Element Range Step Default Remarks

BITRN 0 - 128 1 100 Number of bi-trigger(on/off) events EV1 – EV128 0 - 3071 Assign the signal number

Up to 1024 records can be stored. If an additional event occurs when 1024 records have been stored, the oldest event record is deleted and the latest event record is then stored.

3.4.3 Disturbance Recording

Disturbance Recording is started when overcurrent starter elements operate or a tripping command is output, or PLC command by user-setting (max. 4: Signal No. 2632 to 2635) is output. The records include 13 analog signals (primary: Ia1, Ib1, Ic1, In1, secondary: Ia2, Ib2, Ic2, In2,

tertiary: Ia3, Ib3, Ic3, In3, voltage: V), 32 binary signals and the dates and times at which recording started. Any binary signal in shown in Appendix B can be assigned by the binary signal

setting of disturbance record. The default setting of binary signal is shown in Appendix H. The name of binary signal can be set only by RSM100. Maximum 22 characters can be set and can

be viewed on both of the LCD and RSM Setting(view) screen. But the waveform data analysis screen of disturbance record displays up to 11 characters of them. Therefore, it is recommended the maximum 11 characters are set.

The LCD display only shows the dates and times of the disturbance records stored. Details can be displayed on a PC. For how to obtain disturbance records on the PC, see the PC software instruction manual.

The post-fault recording time can be set between 0.1 and 3.0s and the default setting is 1.0s. The pre-fault recording time depends on the post recording time. The pre-fault recording time is fixed at 0.3s.

⎯ 76 ⎯

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6 F 2 S 0 8 5 7

The number of records stored depends on the post-fault recording time. The approximate relationship between the post-fault recording time and the number of records stored is shown in Table 3.4.2.

Note: If the recording time setting is changed, all previously recorded data is deleted.

Table 3.4.2 Post Fault Recording Time and Number of Disturbance Records Stored

Model 0.1s 0.5s 1.0s 1.5s 2.0s 2.5s 3.0s Frequency

101,102 50Hz 40 34 20 15 11 9 8

60Hz 40 28 17 12 9 8 6 201,202 50Hz 40 25 15 11 8 7 6 203,204 60Hz 40 21 13 9 7 6 5

Recording time

Disturbance recording is initiated when overcurrent elements operate, a tripping signal is output, 2F or 5F element operates or external event signals are input. Three phase overcurrent elements 1OCP-S to 3OCP-S are applied to the line CTs and neutral overcurrent elements 1OCP-G to 3OCP-G to the neutral CTs.

The initiations are blocked by the scheme switches.

Settings

The elements necessary for starting disturbance recording and their setting ranges are shown in the table below.

Element Range Step Default(**) Remarks

1OCP-S 0.10 - 20.00(*) 0.01 Phase overcurrent element 2OCP-S 0.10 - 20.00(*) 0.01 3OCP-S 0.10 - 20.00(*) 0.01 1OCP-G 0.05 - 20.00(*) 0.01 Neutral overcurrent element 2OCP-G 0.05 - 20.00(*) 0.01 3OCP-G 0.05 - 20.00(*) 0.01 Scheme switch

TRIP1 to TRIP5 1OCPS to 3OCPS 1OCPG to 3OCPG 2F 5F EVENT1 to EVENT3

ON/OFF Initiating disturbance record

by tripping by phase overcurrent element by neutral overcurrent element by 2F element by 5F element by external event

(*) : Multiplier of CT secondary rated current (**): Default settings are dependent on the models. See Appendix H.

⎯ 77 ⎯

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3.5 Metering Function

The GRT100 performs continuous measurement of the analogue input quantities. The measurement data shown below are displayed on the LCD of the relay front panel or on the local or remote PC.

6 F 2 S 0 8 5 7

- Magnitude and phase angle of phase current of each winding (Ia1, Ib1, I

- Magnitude and phase angle of neutral current of each winding (In1 up to In3)

- Magnitude and phase angle of symmetrical component current of each winding (I11, I21, I01 up to I13, I23, I03)

- Magnitude and phase angle of phase-to-phase voltage (V)

- Magnitude of phase differential current (I

- Magnitude of residual differential current for REF protection (I

- Percentage of thermal capacity (THM%)

- Frequency

Phase angles above are expressed taking that of positive sequence voltage as a reference phase angle, where leading phase angles are expressed as positive values.

The above system quantities are displayed in values on the primary side or on the secondary side of the CT according to a setting. To display accurate values, it is necessary to set the CT ratio and VT ratio too. For the setting method, see "Setting the transformer parameters" in 4.2.6.7.

da, Idb, Idc

)

up to I

d01

up to Ia3, Ib3, Ic3)

)

d03

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4. User Interface

4.1 Outline of User Interface

The user can access the relay from the front panel. Local communication with the relay is also possible using a personal computer (PC) via an

RS232C port. Furthermore, remote communication is also possible using RSM (Relay Setting and Monitoring), IEC103 communication via an RS485, optical fibre or Ethernet LAN etc.

This section describes the front panel configuration and the basic configuration of the menu tree of the local human machine communication ports and HMI (Human Machine Interface).

4.1.1 Front Panel

As shown in Figure 3.1.13, the front panel is provided with a liquid crystal display (LCD), light emitting diodes (LED), operation keys, connector.

VIEW

and

RESET

6 F 2 S 0 8 5 7

keys, monitoring jack and RS232C

LCD

The LCD screen, provided with a 4-line, 40-character back-light, displays detailed information of the relay interior such as records, status and setting. The LCD screen is normally unlit, but

pressing the

RESET

and

VIEW will display the menu screen.

These screens are turned off by pressing the

key will display the digest screen and pressing any key other than

RESET

key or

END

key. If any display is left for 5

VIEW

minutes or longer without operation, the back-light will go off.

LED

There are 8 LED displays. The signal labels and LED colours are defined as follows:

Label Color Remarks

IN SERVICE Green TRIP Red ALARM Red TESTING Red

(LED1) Red Configurable LED to assign signals with or without latch when relay operates. (LED2) Red Configurable LED to assign signals with or without latch when relay operates. (LED3) Red Configurable LED to assign signals with or without latch when relay operates. (LED4) Red Configurable LED to assign signals with or without latch when relay operates.

Lit when the relay is in service. Lit when a trip command is issued. Lit when a failure is detected. Lit when disabling automatic monitoring function or resetting the

time counting of THR and V/F elements by the scheme switches.

LED1 to LED4 are configurable. The TRIP LED lights up once the relay is operating and remains lit even after the trip command

goes off. The TRIP LED can be turned off by pressing the long as a signal is present and the

RESET

⎯ 79 ⎯

key is invalid while the signal is being maintained.

RESET

key. Other LEDs are lit as

Page 81

6 F 2 S 0 8 5 7

Operation keys

The operation keys are used to display records, status, and set values on the LCD, as well as to input or change set values. The function of each key is as follows:

c 0-9, −: Used to enter a selected number, numerical values and text strings. d , : Used to move between lines displayed on a screen

Keys 2, 4, 6 and 8 marked with

and

are also used to enter text

strings.

CANCEL

e f g

END

ENTER

: Used to cancel entries and return to the upper screen.

: Used to end entry operation, return to the upper screen or turn off the display.

: Used to store or establish entries.

VIEW and RESET keys

Pressing

VIEW

key displays digest screens such as "Metering", "Latest fault" and "Auto-

supervision". Pressing

RESET

key turns off the display.

Monitoring jacks

The two monitoring jacks A and B and their respective LEDs can be used when the test mode is selected on the LCD screen. By selecting the signal to be observed from the "Signal List" and setting it on the screen, the signal can be displayed on LED A or LED B, or transmitted to an oscilloscope via a monitoring jack.

RS232C connector

The RS232C connector is a 9-way D-type connector for serial RS232C connection with a local personal computer.

⎯ 80 ⎯

Page 82

(SC, op

)

6 F 2 S 0 8 5 7

4.1.2 Communication Ports

The following 3 individual interfaces are mounted as the communication ports:

• RS232C port

• Serial communication port (RS485 port, optional Fibre optic or Ethernet LAN etc.)

• IRIG-B port

(1) RS232C port

This connector is a standard 9-way D-type connector for serial port RS232C transmission and mounted on the front panel. By connecting with a personal computer using this connector, setting operation and display functions can be performed on the personal computer.

(2) Serial communication port

Two serial communication ports can be provided. In one port, it is connected to the RSM (Relay Setting and Monitoring system) via the protocol converter G1PR2 or IEC60870-5-103 communication via BCU/RTU (Bay Control Unit / Remote Terminal Unit) to connect between relays and to construct a network communication system. (See Figure 4.4.1 in Section 4.4.)

In another port, it is connected to the substation automation system via Ethernet communication networks using IEC 61850 protocol.

Screw terminal for RS485, ST connector for fibre optic, or 100Base-TX (RJ-45 connector) or 100Base-FX (SC connector) for Ethernet LAN is provided on the back of the relay as shown in Figure 4.1.1.

(3) IRIG-B port

The IRIG-B port is mounted on the transformer module. This port collects serial IRIG-B format data from the external clock to synchronize the relay calendar clock. The IRIG-B port is isolated from the external circuit by using a photocoupler. A BNC connector is used as the input connector.

This port is provided on the back of the relay and Figure 4.1.1 shows the location of this connector.

100Base-TX (RJ45, option)

Opt. I/F for IEC103

36-pin terminal block

20-pin terminal block

IRIG BNC connector

(ST, option)

RS485 connection

100Base-FX

Figure 4.1.1 Locations of Communication Port

terminal

tion

⎯ 81 ⎯

Page 83

4.2 Operation of the User Interface

The user can access such functions as recording, measurement, relay setting and testing with the LCD display and operation keys.

4.2.1 LCD and LED Displays

Displays during normal operation

When the GRT100 is operating normally, the green "IN SERVICE" LED is lit and the LCD is off.

6 F 2 S 0 8 5 7

Press the

VIEW

key when the LCD is off to display the digest screens which are "Metering",

"Latest fault" and "Auto-supervision" screens in turn. The last two screens are displayed only when there is some data. The following are the digest screens and can be displayed without entering the menu screens.

Ia1 ***.*kA Ia **.**kA

*** ***

Ia3 ***.*kA

*** ***

Press the

RESET

key to turn off the LCD.

2 * *

* *

** **

In **.**kA

*** **

For any display, the back-light is automatically turned off after five minutes.

Displays in tripping

Phase BC Tri

1-2-3-

:**

***

If a fault occurs and a tripping command is output when the LCD is off, the red "TRIP" LED and other configurable LED if signals assigned to trigger by tripping.

Press the Press the

VIEW

RESET

key to scroll the LCD screen to read the rest of messages.

key to turn off the LEDs and LCD display.

Notes:

1) When configurable LEDs (LED1 through LED4) are assigned to latch signals by trigger of

tripping, press the the configurable LEDs. Refer to Table 4.2.1 Step 1.

2) Then, press the

RESET

key more than 3s until the LCD screens relight. Confirm turning off

key again on the "Latest fault" screen in short period, confirm turning

⎯ 82 ⎯

Page 84

off the "TRIP" LED. Refer to Table 4.2.1 Step 2.

3) When only the "TRIP" LED is go off by pressing the

RESET

6 F 2 S 0 8 5 7

key in short period, press the

RESET

digest screens. LED1 through LED4 will remain lit in case the assigned signals are still active state.

key again to reset remained LEDs in the manner 1) on t he "Latest fault" screen or other

Table 4.2.1 Turning off latch LED operation

Operation

Step 1

Step 2

Press the the "Latest fault" screen

Then, press the period on the "Latest fault" screen

RESET

key more than 3s on

RESET

key in short

When any of the menu screens is displayed, the

LED lighting status

"TRIP" LED Configurable LED

(LED1 - LED4)

continue to lit

turn off

VIEW

and

RESET

turn off

keys do not function.

To return from menu screen to the digest "Latest fault" screen, do the following:

• Return to the top screen of the menu by repeatedly pressing the

• Press the

END

key to turn off the LCD.

VIEW

key to display the digest "Latest fault" screen.

END

key.

Displays in automatic supervision operation

A u t o - s u p e r v i s i o n 0 8 / D e c / 1 9 9 7 2 2 : 5 6

DI O r e r

If the automatic supervision function detects a failure while the LCD is off, the "Auto-supervision" screen is displayed automatically, showing the location of the failure and the "ALARM" LED lights.

Press the

VIEW

key to display other digest screens in turn including the "Metering" and "Latest

fault" screens. Press the

RESET

key to turn off the LEDs and LCD display. However, if the failure continues,

the "ALARM" LED remains lit. After recovery from a failure, the "ALARM" LED and "Auto-supervision" display turn off

automatically. If a failure is detected while any of the screens is displayed, the current screen remains displayed

and the "ALARM" LED lights.

Notes:

⎯ 83 ⎯

Page 85

1) When configurable LEDs (LED1 through LED4) are assigned to latch signals by issuing an

alarm, press the

2) When configurable LED is still lit by pressing

again to reset remained LED in the above manner.

3) LED1 through LED4 will remain lit in case the assigned signals are still active state.

RESET

key more than 3s until all LEDs reset except "IN SERVICE" LED.

RESET

key in short period, press

6 F 2 S 0 8 5 7

RESET

key

While any of the menu screens is displayed, the

VIEW

and

RESET

keys do not function. To

return to the digest "Auto-supervision" screen, do the following:

• Return to the top screen of the menu by repeatedly pressing the

• Press the

END

key to turn off the LCD.

VIEW

RESET

key to display the digest screen.

key to turn off the LCD.

END

key.

4.2.2 Relay Menu

Figure 4.2.1 shows the menu hierarchy in the GRT100. The main menu has five sub-menus, "Record", "Status", "Setting (view)", "Setting (change)", and "Test". For details of the menu hierarchy, see Appendix E.

⎯ 84 ⎯

Page 86

6 F 2 S 0 8 5 7

Record Fault record

Event record Disturbance record

Status Metering

Binary input & output Relay element Time synchronization source Clock adjustment

Setting (view) Relay vers ion

Record Status Protection

Binary output LED

Description Communication

Binary input

Setting (change) Password Description Communication Record Status Protection Binary input Binary output LED

Test Switch Binary output Timer Logic circuit

Figure 4.2.1 Relay Menu

⎯ 85 ⎯

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6 F 2 S 0 8 5 7

Record

In the "Record" menu, the fault records, event records and disturbance records are displayed or erased.

Status

The "Status" menu displays the power system quantities, binary input and output status, relay measuring element status, signal source for time synchronization (IRIG-B, RSM or IEC) and adjusts the clock.

Setting (view)

The "Setting (view)" menu displays the relay version, plant name and the current settings of relay address and RS232C baud rate in communication, record, status, protection, configurable binary inputs and outputs, and configurable LEDs.

Setting (change)

The "Setting (change)" menu is used to set or change the settings of password, plant name, relay address and RS232C baud rate in communication, record, status, protection, configurable binary inputs and outputs, and configurable LEDs.

Since this is an important menu and is used to set or change settings related to relay tripping, it has password security protection.

Test

The "Test" menu is used to set testing switches, to forcibly operate binary output relays, to measure variable timer time and to observe the binary signals in the logic circuit.

This menu also has password security protection.

When the LCD is off, press any key other than the

VIEW

and

keys to display the top

RESET

"MENU" screen and then proceed to the relay menus.

MENU 1=Record 2=Status 3=Setting(view) 4=Setting(change) 5=Test

To display the "MENU" screen when the digest screen is displayed, press the off the LCD, then press any key other than the

END

Press the

key when the top screen is displayed to turn off the LCD.

VIEW

and

RESET

keys.

RESET

key to turn

An example of the sub-menu screen is shown below. The top line shows the hierarchical layer of the screen, screen title and total number of lines of the screen. The last item is not displayed for all the screens. "/6" displayed on the far left means that the screen is in the sixth hierarchical layer, while 1/7 displayed on the far right means that the screen has seven lines excluding the top line and that the cursor is on the first line.

To move the cursor downward or upward for setting or for viewing other lines not displayed on the window, use the

and keys.

⎯ 86 ⎯

Page 88

(

)

/ 6 V T & T C r a t i o 1 / 7 1 C T

3 C T ( 1 1 n C T

2 n C T 3 n C T

V T

1-20O0

( 1 - 2 0 O 0 )0: 100 ( )1- :20O00 100 ( (

1- 20O0 )0:

0 :2000

)2 C T ( 1 - :20O00 1000 )

:20O00

)1- :20O00

400

100 400

6 F 2 S 0 8 5 7

To move to the lower screen or move from the left-side screen to the right-side screen in Appendix E, select the appropriate number on the screen. To return to the higher screen or move from the

END

right-side screen to the left-side screen, press the

key.

The

CANCEL

key can also be used to return to the higher screen but it must be used carefully

because it may cancel entries made so far. To move between screens of the same hierarchical depth, first return to the higher screen and then

move to the lower screen.

4.2.3 Displaying Records

The sub-menu of "Record" is used to display fault records, event records and disturbance records.

4.2.3.1 Displaying Fault Records

To display fault records, do the following:

• Open the top "MENU" screen by pressing any keys other than the

• Select 1 (= Record) to display the "Record" sub-menu.

record

2=Event

reco r d

R e c o

/ 1

1 = r e c o r d

a u

3 = D i s t u r b a n c e

• Select 1 (= Fault record) to display the "Fault record" screen.

/ 2 1 =

a u t F l

i s l D p

R e c o r

2=Clear

VIEW

and

RESET

keys.

• Select 1 (= Display) to display the dates and times of fault records stored in the relay from the

top in new-to-old sequence.

/ 3 F a u l t r e c o r d 1 / 4 #

1 1 6 / O c t / 1 9 9 7 1 8 : 1 3 : 5 7 . 0 3 1 # 2 2 0 / S e p /1997 15:29:22.463 # 3 0 4 / J u l /1997 11:54:53.977

• Move the cursor to the fault record line to be displayed using the and keys and press the

ENTER

key to display the details of the fault record.

⎯ 87 ⎯

Page 89

Date and Time

Fault phase

Tripping mode

Power system quantities

／４ＦａｕｌｔＲｅｃｏｒｄ＃１３／４２１６／Ｏｃｔ／１９９７１８ＰｈａｓｅＢＣＴｒｉｐＤＩＦＴ

ＰｒｅｆａｕｌｔｖａｌｕｅｓＩａ１＊＊．＊＊ｋＡ＊＊＊．＊° ｌａ２＊＊．＊＊ｋＡ＊＊＊．＊° Ｉｂ１＊＊．＊＊ｋＡ＊＊＊．＊° ｌｂ２＊＊．＊＊ｋＡ＊＊＊．＊° Ｉｃ１＊＊．＊＊ｋＡ＊＊＊．＊° ｌｃ２＊＊．＊＊ｋＡ＊＊＊．＊° Ｉ１１＊＊．＊＊ｋＡ＊＊＊．＊° ｌ１２＊＊．＊＊ｋＡ＊＊＊．＊° Ｉ２１＊＊．＊＊ｋＡ＊＊＊．＊° ｌ２２＊＊．＊＊ｋＡ＊＊＊．＊° Ｉ０１＊＊．＊＊ｋＡ＊＊＊．＊° ｌ０２＊＊．＊＊ｋＡ＊＊＊．＊° Ｉｎ１＊＊．＊＊ｋＡ＊＊＊．＊° ｌｎ２＊＊．＊＊ｋＡ＊＊＊．＊° Ｉａ３＊＊．＊＊ｋＡ＊＊＊．＊° Ｉｂ３＊＊．＊＊ｋＡ＊＊＊．＊° Ｉｃ３＊＊．＊＊ｋＡ＊＊＊．＊° Ｉ１３＊＊．＊＊ｋＡ＊＊＊．＊° Ｉ２３＊＊．＊＊ｋＡ＊＊＊．＊° Ｉ０３＊＊．＊＊ｋＡ＊＊＊．＊° Ｉｎ３＊＊．＊＊ｋＡ＊＊＊．＊° Ｖ＊＊＊．＊ｋＶ＊＊＊．＊° Ｉｄａ＊＊＊．＊＊ｐｕｌｄ０１＊＊＊．＊＊ｐｕＩｄｂ＊＊＊．＊＊ｐｕｌｄ０２＊＊＊．＊＊ｐｕ

Ｉｄｃ＊＊＊．＊＊ｐｕｌｄ０３＊＊＊．＊＊ｐｕ

：１３：５７．０３１

１-２-３-４-５

6 F 2 S 0 8 5 7

CB tripped

ＦａｕｌｔｖａｌｕｅｓＩａ１＊＊．＊＊ｋＡ＊＊＊．＊° ｌａ２＊＊．＊＊ｋＡ＊＊＊．＊°

Ｉｂ１＊＊．＊＊ｋＡ＊＊＊．＊° ｌｂ２＊＊．＊＊ｋＡ＊＊＊．＊° Ｉｃ１＊＊．＊＊ｋＡ＊＊＊．＊° ｌｃ２＊＊．＊＊ｋＡ＊＊＊．＊° Ｉ１１＊＊．＊＊ｋＡ＊＊＊．＊° ｌ１２＊＊．＊＊ｋＡ＊＊＊．＊° Ｉ２１＊＊．＊＊ｋＡ＊＊＊．＊° ｌ２２＊＊．＊＊ｋＡ＊＊＊．＊° Ｉ０１＊＊．＊＊ｋＡ＊＊＊．＊° ｌ０２＊＊．＊＊ｋＡ＊＊＊．＊° Ｉｎ１＊＊．＊＊ｋＡ＊＊＊．＊° ｌｎ２＊＊．＊＊ｋＡ＊＊＊．＊° Ｉａ３＊＊．＊＊ｋＡ＊＊＊．＊° Ｉｂ３＊＊．＊＊ｋＡ＊＊＊．＊° Ｉｃ３＊＊．＊＊ｋＡ＊＊＊．＊° Ｉ１３＊＊．＊＊ｋＡ＊＊＊．＊° Ｉ２３＊＊．＊＊ｋＡ＊＊＊．＊° Ｉ０３＊＊．＊＊ｋＡ＊＊＊．＊° Ｉｎ３＊＊．＊＊ｋＡ＊＊＊．＊° Ｖ＊＊＊．＊ｋＶ＊＊＊．＊° Ｉｄａ＊＊＊．＊＊ｐｕｌｄ０１＊＊＊．＊＊ｐｕＩｄｂ＊＊＊．＊＊ｐｕｌｄ０２＊＊＊．＊＊ｐｕＩｄｃ＊＊＊．＊＊ｐｕｌｄ０３＊＊＊．＊＊ｐｕＴＨＭ＊＊＊．＊％

Note: I 1 for primary(high-voltage) winding current I 2 for secondary(medium-voltage) winding current I 3 for tertiary(low-voltage) winding current In for neutral current I1, I2, I0 for symmetrical component current Ida, Idb, Idc for differential current Ido1, Ido2, Ido3 for zero-phase differential current in 1REF, 2REF, 3REF

The lines which are not displayed in the window can be displayed by pressing the and keys. To clear all the fault records, do the following:

• Open the "Record" sub-menu.

• Select 1 (Fault record) to display the "Fault record" screen.

• Select 2 (= Clear) to display the following confirmation screen.

⎯ 88 ⎯

Page 90

/2 Fault record Clear all fault records?

ENTER=Yes CANCEL=No

6 F 2 S 0 8 5 7

• Press the

ENTER

(= Yes) key to clear all the fault records stored in non-volatile memory.

If all fault records have been cleared, the "Latest fault" screen of the digest screens is not displayed.

4.2.3.2 Displaying Event Records

To display events records, do the following:

• Open the top "MENU" screen by pressing any keys other than the

VIE

and

RESET

keys.

• Select 1 (= Record) to display the "Record" sub-menu.

• Select 2 (= Event record) to display the "Event record" screen.

/ 2 1 =

v e t E n

i s l D p

R e c o r

2=Clear

• Select 1 (= Display) to display the events with date and time from the top in new-to-old

sequence.

/3 Event record 2/48 16/Oct/1998 23:18:04.294 Tri 16/Oct/1998 23:18:03.913 12/Feb/1998 03:51:37.622 Rl

Trip

The lines which are not displayed in the window can be displayed by pressing the

Off On

cha gne

and keys.

To clear all the event records, do the following:

• Open the "Record" sub-menu.

• Select 2 (Event record) to display the "Event record" screen.

• Select 2 (= Clear) to display the following confirmation screen.

/2 Event record Clear all event records?

ENTER=Yes CANCEL=No

• Press the

ENTER

(= Yes) key to clear all the event records stored in non-volatile memory.

4.2.3.3 Displaying Disturbance Records

Details of the disturbance records can be displayed on the PC screen only (*); the LCD displays only the recorded date and time for all disturbances stored in the relay. To display them, do the following:

(*) For the display on the PC screen, refer to RSM100 manual.

• Open the top "MENU" screen by pressing any keys other than the

VIE

and

RESET

keys.

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6 F 2 S 0 8 5 7

• Select 1 (= Record) to display the "Record" sub-menu.

• Select 3 (= Disturbance record) to display the "Disturbance record" screen.

/ 2 1 =

i s u D t r b a n c e

i s l D p

recor

2=Clear

• Select 1 (= Display ) to display the date and time of the disturbance records from the top in

new-to-old sequence.

/3 Disturbance record 3/12 #1 16/Oct/1997 18:13:57.031 #2 20/Sep/1997 15:29:22.463 #

3 04/Jul/1997 11:54:53.977

The lines which are not displayed in the window can be displayed by pressing the

and keys.

To clear all the disturbance records, do the following:

• Open the "Record" sub-menu.

• Select 3 (Disturbance record) to display the "Disturbance record" screen.

• Select 2 (= Clear) to display the following confirmation screen.

/2 Disturbance record Clear all disturbance records?

ENTER=Yes CANCEL=No

• Press the

ENTER

(= Yes) key to clear all the disturbance records stored in non-volatile

memory.

4.2.4 Displaying the Status

From the sub-menu of "Status", the following statuses can be displayed on the LCD: Metering data of the protected transformer Status of binary inputs and outputs Status of measuring elements output Status of time synchronization source The data are renewed every second. This sub-menu is also used to adjust the time of the internal clock.

4.2.4.1 Displaying Metering Data

To display metering data on the LCD, do the following.

• Select 2 (= Status) on the top "MENU" screen to display the "Status" screen.

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∗∗∗.∗

∗

∗.∗

∗

∗∗∗.∗

∗

∗.∗

∗

∗∗∗.∗

∗

∗.∗

∗

∗∗∗.∗

∗

∗.∗

∗

∗∗∗.∗

∗

∗.∗

∗

∗∗∗.∗

∗

∗.∗

∗

∗∗∗.∗

∗

∗.∗

∗

∗∗∗.∗

∗∗∗

∗∗∗.∗

∗

∗.∗

∗∗∗

6 F 2 S 0 8 5 7

/1 Status 1=Metering 2=Binary I/O 3=Relay element 4=Time sync source 5=Cloc

adjustme

• Select 1 (= Metering) to display the "Metering" screen.

/2 Metering 16/Oct/1997 18:13 3/20 Ia1 ∗∗. ∗∗kA

Ib1 ∗∗. ∗∗kA Ic1 ∗∗. ∗∗kA

I11 ∗∗. ∗∗kA I21 ∗∗. ∗∗kA

I01 ∗∗. ∗∗kA In1 ∗∗. ∗∗kA

Ia3 ∗∗. ∗∗kA Ib3 ∗∗. ∗∗kA Ic3 ∗∗. ∗∗kA I13 ∗∗. ∗∗kA I23 ∗∗. ∗∗kA I03 ∗∗. ∗∗kA In3 ∗∗. ∗∗kA V ∗∗∗. ∗ kV

Ida ∗∗∗. ∗∗pu Id01 Idb ∗∗∗. ∗∗pu Id02 Idc ∗∗∗. ∗∗pu Id03 THM ∗∗∗. ∗ %

Frequency

° Ia2 ° Ib2 ° Ic2

° I12 ° I22

° I02 ° In2

° ° ° ° ° ° °

Note: I 1 for primary(high-voltage) winding current I 2 for secondary(medium-voltage) winding current I 3 for tertiary(low-voltage) winding current Ia, Ib, Ic for phase current In for neutral current I1, I2, I0 for symmetrical component current Ida, Idb, Idc for differential current Ido1, Ido2, Ido3 for zero-phase differential current in 1REF, 2REF, 3REF

kA ∗∗∗. ∗° kA ∗∗∗. ∗° kA ∗∗∗. ∗°

kA ∗∗∗. ∗° kA ∗∗∗. ∗°

. ∗∗pu . ∗∗pu . ∗∗pu

Metering data is expressed as primary values or secondary values depending on the setting. For setting, see Section 4.2.6.6.

⎯ 91 ⎯

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6 F 2 S 0 8 5 7

4.2.4.2 Displaying the Status of Binary Inputs and Outputs

To display the binary input and output status, do the following:

• Select 2 (= Status) on the top "MENU" screen to display the "Status" screen.

• Select 2 (= Binary I/O) to display the binary input and output status. (Binary inputs and outputs

depend oh the relay model.)

Outp ut

000 000 000 0

The display format is shown below.

[              ] Input (IO#1) BI1 BI2 BI3 BI4 BI5 BI6 BI7 BI8 BI9 BI10 BI11 BI12 — — — Input (IO#2) BI14 BI15 BI16 — — — — — — — — — — — — Output (IO#1-trip) TP-1 TP-2 TP-3 TP-4 TP-5 — — — — — — — — — — Output (IO#2) BO1 BO2 BO3 BO4 BO5 BO6 Output (IO#3) BO1 BO2 BO3 BO4 BO5 BO6

BO7 BO8 BO9 BO10 BO11 BO12 FAIL BO13 — BO7 BO8 BO9 BO10 — — — — —

Lines 1 and 2 show the binary input status. BI1 to BI16 corresponds to each binary input signal. For details of the binary input signals, see Appendix G. The status is expressed with logical level "1" or "0" at the photo-coupler output circuit. IO#1 and IO#2 in the table indicates the name of the module containing the binary input circuits.

Lines 3 to 5 show the binary output status. TP-1 to TP-5 of line 3 corresponding to the tripping command outputs. Models 203 and 204 are not provided with TP-4 and TP-5. FAIL of line 4 corresponds to the relay failure output. Other outputs expressed with BO1 to BO13 are configurable. The status of these outputs is expressed with logical level "1" or "0" at the input circuit of the output relay driver. That is, the output relay is energized when the status is "1".

IO#1 to IO#3 in the table indicate the names of the module containing the binary output relays. To display all the lines, press the

and keys.

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6 F 2 S 0 8 5 7

4.2.4.3 Displaying the Status of Measuring Elements

To display the status of the measuring elements on the LCD, do the following:

• Select 2 (= Status) on the top "MENU" screen to display the "Status" screen.

• Select 3 (= Relay element) to display the status of the relay elements.

2Rela

element 3

RFE

000

The display format is as shown below.

[      A B C A B C A B C A B C

DIFT

DIF

REF

A B C A B C

1OC A B C A B C A B C

OCI

1OCI

EFI

1 2 3 — — — — — — — — — — — —

1 2 3

2f 5f HOC

2OC

2OCI

— — — — — — — — — — — —

— — —

  

A B C

3OC

3OCI

     ]

— — —

— — — — — — — — —

THR S A — — — — V/F H T A — — — FRQ L1 L2 H1 H2 — —

Line 1 shows the operation status of current differential elements. Line 2 shows the status of restricted earth fault elements. Line 3 shows the status of overcurrent elements. Line 4 shows the status of time overcurrent elements. Line 5 shows the status of the overcurrent element for earth fault. Line 6 shows the status of time overcurrent elements for earth fault. Lines 7, 8 and 9 show the status of thermal overload element, overexcitation element and frequency element respectively.

The status of each element is expressed with logical level "1" or "0". Status "1" means the element is in operation.

To display all the lines on the LCD, press the

⎯ 93 ⎯

— — — — — — — — — — — — — — — — — — — — — — — — — — —

and keys.

Page 95

∗

6 F 2 S 0 8 5 7

4.2.4.4 Displaying the Status of the Time Synchronization Source

The inner clock of the GRT100 can be synchronized with external clocks such as the IRIG-B time standard signal clock or RSM (relay setting and monitoring system) clock or by an IEC60870-5-103 or SNTP server. To display on the LCD whether these clocks are active or inactive and which clock the relay is synchronized with, do the following:

• Select 2 (= Status) on the top "MENU" screen to display the "Status" screen.

• Select 4 (= Time sync source) to display the status of time synchronization sources.

4 / 4 m e s y nchron zation s rceiouT i

I R I G I n a c t: eiv R S M I n a ict: v e I E C I n a ict: v e

* SN T P : (Serv

)erA ic t v e

The asterisk on the far left shows that the internal clock is synchronized with the marked source clock. If the marked source clock is inactive, the internal clock runs locally.

For details of the setting time synchronization, see Section 4.2.6.6.

4.2.4.5 Adjusting the Time

To adjust the clock when the internal clock is running locally, do the following:

• Select 2 (= Status) on the top "MENU" screen to display the "Status" screen.

• Select 5 (= Clock adjustment) to display the setting screen.

/2 12/Feb/1998 22:56:19 [local] 1/ 5 Minute( 0- 59): 41 Hour ( 0- 23): 22 Day ( 1- 31): 12 Month ( 1- 12): 2 Year ( 1990- 2089): 1998

Line 1 shows the current date, time and time synchronization source with which the internal clock is synchronized. The time can be adjusted only when [Local] is indicated on the top line, showing that the clock is running locally. When [IRIG] or [RSM] or [IEC] or [SNTP] is indicated, the following adjustment is invalid.

• Enter a numerical value within the specified range for each item and press the

• Press the

END

key to adjust the internal clock to the set hours without fractions and return to

ENTER

key.

the previous screen.

If a date which does not exist in the calendar is set and

END

is pressed, "Error: Incorrect date" is

displayed on the top line and the adjustment is discarded. Adjust again.

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4.2.5 Viewing the Settings

The sub-menu "Setting (view)" is used to view the settings made using the sub-menu "Setting (change)" except for the relay version.

The following items are displayed: Relay version

Description Address in the RSM, IEC60870-5-103 or IEC61850 communication Recording setting Status setting Protection setting Binary input setting Binary output setting LED setting

Enter a number on the LCD to display each item as described in the previous sections.

4.2.5.1 Relay Version

To view the relay version, do the following.

• Press 3 (= Setting (view)) on the main "MENU" screen to display the "Setting (view)" screen.

1=Version

= =

2=Description 3=

6=Protection

9=LED

• Press 1 (= Version) on the "Setting (view)" screen and the "Relay version" screen appears.

R e l a y S e r i a l M a i n s o f t w a r e :

I E C 6 1 8 P L C

G O O S E s u b s c r i p t :

t y p

d a t a : * * * * * * * * * * * *

N o . :

eng

d a t a :

********************** ********************** **************** * * * * * *

**********************

******** ************ ************ ************

******** ******** ********

3 / 8

4.2.5.2 Settings

The "Description", "Comm.", "Record", "Status", "Protection", "Binary input", "Binary output" and "LED" screens display the current settings input using the "Setting (change)" sub-menu.

4.2.6 Changing the Settings

The "Setting (change)" sub-menu is used to make or change settings for the following items: Password

Description Address in the RSM, IEC60870-5-103 or IEC61850 communication

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Recording Status Protection Binary input Binary output LED

All of the above settings except the password can be seen using the "Setting (view)" sub-menu.

4.2.6.1 Setting Method

There are three setting methods as follows.

- To enter a selective number

- To enter numerical values

- To enter a text string

To enter a selected number

If a screen as shown below is displayed, perform setting as follows. The number to the left of the cursor shows the current setting or default setting set at shipment. The

cursor can be moved to upper or lower lines within the screen by pressing the setting (change) is not required, skip the line with the

6 S c h e m e 1 /

DIF T 1 =3P

M2O C I 1 =Lo

switch

= = =

= =

= = =

=Lo

= =

0 =Of

2=1P

02=2I0 =33I0

f f f

= = =

2=Std =3 Veryg1

1=OnL/O

= = =OnDIF 1 = =OnDIF 3

1=OnM . T 4 1 - 1=OnM . T 4 2 - 1=OnM . T 4 3 -

1=OnCTS E N

and keys.

= =

= = = =

y y y y4= t Ex

=t Ex =t Ex =t Ex =t Ex =t Ex

and keys. If

* * *

1 0 =Of

: : 1 0 =Of 1 0 =Of 1 0 =Of : : 1 0 =ALMBLK 1= MLA&SVC N T 1 0 =Of

• Move the cursor to a setting line.

• Enter the selected number. (Numbers other than those displayed cannot be entered.)

• Press the

ENTER

key to confirm the entry and the cursor will move to the next line below.

(On the lowest line, the entered number blinks.)

• After completing the setting on the screen, press the

⎯ 96 ⎯

END

key to return to the upper menu.

Page 98

CANC

6 F 2 S 0 8 5 7

To correct the entered number, do the following.

• If it is before pressing the

• If it is after pressing the

and

keys and enter the new number.

Note: If the

the entries performed so far on the screen concerned are canceled and screen returns to the upper one.

key is pressed after any entry is confirmed by pressing the

ENTER

key, press the

key, move the cursor to the correct line by pressing the

CANCEL

key and enter the new number.

ENTE

key, all

When the screen shown below is displayed, perform setting as follows. The number to the right of "Current No.=" shows the current setting.

1=Group 1 2=

Group2 3=Group3 4=Group 4

• Enter a number to the right of "Select No. = ". (Numbers other than those displayed cannot be

entered.)

• Press the

• After completing the setting on the screen, press the

ENTER

key to confirm the entry and the entered number blinks.

END

key to return to the upper screen.

To correct the entered number, do the following.

• If it is before pressing the

• If it is after pressing the

ENTER

key, press the

key, enter the new number.

CANCEL

key and enter the new number.

To enter numerical values

When the screen shown below is displayed, perform setting as follows: The number to the left of the cursor shows the current setting or default setting set at shipment. The

cursor can be moved to upper or lower lines within the screen by pressing the setting (change) is not required, skip the line with the

6VT

2nCT

ratio

1- 20000

：100

：400

and keys.

and keys. If

• Move the cursor to a setting line.

• Enter the numerical value.

• Press the

ENTER

key to confirm the entry and the cursor will move to the next line below. (If a numerical value outside the displayed range is entered, "Error: Out of range" appears on the top line and the cursor remains on the line. Press the

• After completing the setting on the screen, press the

⎯ 97 ⎯

CANCEL

END

key to clear the entry.)

key to return to the upper screen.

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CANC

6 F 2 S 0 8 5 7

To correct the entered numerical value, do the following.

• If it is before pressing the

ENTER

key, press the

CANCEL

key and enter the new

numerical value.

• If it is after pressing the

and

keys and enter the new numerical value.

Note: If the

the entries made so far on the screen concerned are canceled and the screen returns to the upper one.

ENTER

key is pressed after any entry is confirmed by pressing the

key, move the cursor to the correct line by pressing the

ENTE

key, all

To enter a text string

Text strings are entered in the bracket under the "Plant name" or "Description" screen. To select a character, use keys 2, 4, 6 and 8 to move the blinking cursor down, left, right and up.

→" and "←" on each of lines 2 to 4 indicate a space and backspace, respectively. A maximum of

" 22 characters can be entered within the brackets.

/3 Plant name ]_[

←

→← →← →

ENTER

key.

ABCDEFGHIJKLMNOPQRSTUVWXYZ ()[]@_

abcdefghi 0123456789 !”#$%&’：；，．^`

klmno

rstuvwxyz {}*/+-<=>

• Set the cursor position in the bracket by selecting "→" or "←" and pressing the

• Move the blinking cursor to select a character.

• Press the

ENTER

END

to enter the blinking character at the cursor position in the brackets.

key to confirm the entry and return to the upper screen.

To correct the entered character, do either of the following.

• Discard the character by selecting "←" and pressing the

ENTER

key and enter the new

character.

• Discard the whole entry by pressing the

CANCEL

key and restart the entry from the first.

To complete the setting

Enter after making entries on each setting screen by pressing the

ENTER

key, the new settings

are not yet used for operation, though stored in the memory. To validate the new settings, take the following steps.

• Press the

END

key to the upper screen. Repeat this until the confirmation screen shown

below is displayed. The confirmation screen is displayed just before returning to the "Setting (change)" sub-menu.

/2 ************** Change settings?

ENTER=Yes CANCEL=No

• When the screen is displayed, press the

or press the

CANCEL

key to correct or cancel entries. In the latter case, the screen turns back

to the setting screen to enable re-entries. Press the

ENTER

⎯ 98 ⎯

key to start operation using the new settings,

CANCEL

key to cancel entries made so far

Page 100

6 F 2 S 0 8 5 7

and to turn to the "Setting (change)" sub-menu.

4.2.6.2 Password

For the sake of security of changing the settings and testing the relay, password protection can be set as follows;

• Press 4 (= Setting (change)) on the main "MENU" screen to display the "Setting (change)"

screen.

/1 Setting 1=Password 4=Record 7=Binar

(chang )e

2=Description 3=RSM comm 5=Status

nput 8=Binayrtoutpu

6=Protection

9=LED

• Press 1 (= Password) to display the "Password" screen.

/2 Password

Input new password [

Retype new password [ ]

]

• Enter a 4-digit number within the brackets after "Input new password" and press the

ENTER

key.

• For confirmation, enter the same 4-digit number in the brackets after "Retype new password"

and press the

• Press the

ENTER

key to display the confirmation screen. If the retyped number is different from

END

key.

that first entered, the following message is displayed on the bottom of the "Password" screen before returning to the upper screen.

"Mismatch-password unchanged." Re-entry is then requested.

• Press 2 (= Test) on the "Password" screen to set the password for the test.

/ 2 T e s t

I n p u t n e w p a s s w o r d [

R e t y p e n e w p a s s w o r d [ ]

]

Set the password the same manner as that of the "Setting" above.

Password trap

After the password has been set, the password must be entered in order to enter the setting change and the test screens.

If 4 (= Setting (change)) is entered on the top "MENU" screen, the password trap screen "Password" is displayed. If the password is not entered correctly, it is not possible to move to the "Setting (change)" sub-menu screens.

Password

Input password [

]

⎯ 99 ⎯

Toshiba GRT100 User Manual

Specifications and Main Features

Frequently Asked Questions

User Manual