GE MFAC 14, MFAC 34 User Manual

GE Energy Connections
Grid Solutions

MFAC

14, 34

User Manual
High Impedance Differential Relay

Publication reference: R8007H

HANDLING OF ELECTRONIC EQUIPMENT

A person’s normal movements can easily generate electrostatic potentials of several
thousand volts. Discharge of these voltages into semiconductor devices when
handling circuits can cause serious damage, which often may not be immediately
apparent but the reliability of the circuit will have been reduced.

The electronic circuits of General Electric products are immune to the relevant
levels of electrostatic discharge when housed in their cases. Do not expose them
to the risk of damage by withdrawing modules unnecessarily.

Each module incorporates the highest practicable protection for its semiconductor
devices. However, if it becomes necessary to withdraw a module, the following
precautions should be taken to preserve the high reliability and l

ong life for which

the equipment has been designed and manufactured.

1. Before removing a module, ensure that you are a same electrostatic
potential as the equipment by touching the case.

2. Handle the module by its front-plate, frame, or edges of the printed circuit
board. Avoid touching the electronic components, printed circuit track or
connectors.

3. Do not pass the module to any person without first ensuring that you are both
at the same electrostatic potential. Shaking hands achieves equipotential.

4. Place the module on an antistatic surface, or on a conducting surface which is
at the same potential as yourself.

5. Store or transport the module in a conductive bag.

More information on safe working procedures for all electronic equipment can be
found in BS5783 and IEC 60147-0F.

If you are making measurements on the internal electronic circuitry of an
equipment in service, it is preferable that you are earthed to the case with a
conductive wrist strap.

Wrist straps should have a resistance to ground between 500k – 10M ohms. If a
wrist strap is not available you should maintain regular contact with the case to
prevent the build up of static. Instrumentation which may be used for making
measurements should be earthed to the case whenever possible.

General Electric strongly recommends that detailed investigations on the electronic
circuitry, or modification work, should be carried out in a Special Handling Area such
as described in BS5783 or IEC 60147-0F.

TYPES: MFAC 14

MFAC 34

CONTENTS

SAFETY SECTION

5

1. INSTALLATION

9

1.1 General

9

1.2 Unpacking

9

1.3 Storage

9

1.4 Site

9

2. COMMISSIONING

10

2.1 Description of relay, calculation of setting and

commissioning

preliminaries

10

2.2

Instructions

to ensure that the relay can be

commissioned

at the specific settings

for the application

12

3. MAINTENANCE

18

4. MECHANICAL SETTINGS

18

4.1 General

18

4.2 Contact settings

18

4.3 Mechanical flag settings

18

5. PROBLEM ANALYSIS

19

5.1 Failure to operate

19

5.2 Output contacts not changing state

19

6. SPARES

20

7. COMMISSIONING TEST RECORD

21

REPAIR FORM 23

4

1.

SAFETY SECTION

This Safety Section should be read before commencing any work on the
equipment.

1.1

Health and

safety

The information in the Safety Section of the product documentation is intended to
ensure that products are properly installed and handled in order to maintain them in a
safe condition. It is assumed that everyone who will be associated with the
equipment will be familiar with the contents of the Safety Section

.

1.2

Explanatio

n of symbols and

labels

The meaning of symbols and labels may be used on the equipment or in the product
documentation, is given below.

Caution

: refer to product documentation

Caution

: risk of electric shock

Protective/safety *earth terminal

Functional *earth terminal
Note: This symbol may also be

used for a protective/safety earth
terminal if that terminal is part of a
terminal block or sub-assembly
e.g. power supply.

*NOTE: THE TERM EARTH USED THROUGHOUT THE PRODUCT DOCUMENTATION IS

THE DIRECT EQUIVALENT OF THE NORTH AMERICAN TERM GRO U ND.

2.

INSTALLING, COMMISSIONING AND SERVICIN

G

Equipment connections
Personnel undertaking installation, commissioning or servicing work on this

equipment should be aware of the correct working procedures to ensure safety. The
product documentation should be consulted before installing, commissioning or
servicing the equipment.

Terminals exposed during installation, commissioning and maintenance may present
a hazardous voltage unless the equipment is electrically isolated.

If there is unlocked access to the rear of the equipment, care should be taken by all
personnel to avoid electrical shock or energy hazards.

Voltage and current connections should be made using insulated crimp
terminations to ensure that terminal block insulation requirements are maintained for
safety. To ensure that wires are correctly terminated, the correct crimp terminal and
tool for the wire size should be used.

Before energising the equipment it must be earthed using the protective
earth terminal, or the appropriate termination of the supply plug in the case of plug
connected equipment. Omitting or disconnecting the equipment earth may cause a
safety hazard.

The recommended minimum earth wire size is 2.5mm

2,

unless otherwise stated in

the technical data section of the product documentation.
Before energising the equipment, the following should be

checked:

− Voltage rating and polarity;

− CT circuit rating and integrity of connections;

− Protective fuse rating;

−

Integrity of earth connection (where applicable)

−

Remove front plate plastic film protection

−

Remove insulating strip from battery compartment

3.

EQUIPMENT OPERATING CONDITIONS

The equipment should be operated within the specified electrical and environmental
limits.

3.1

Current transformer circuits
Do not open the secondary circuit of a live CT since the high level voltage produced

may be lethal to personnel and could damage insulation.

3.2

External re

sist

ors

Where external resistors are fitted to relays, these may present a risk of electric
shock or burns, if touched.

3.3

Battery replacement
Where internal batteries are fitted they should be replaced with the

recommended type and be installed with the correct polarity, to avoid possible
damage to the equipment.

3.4

Insulation

and

dielectric strength testing

Insulation testing may leave capacitors charged up to a hazardous voltage. At
the end of each part of the test, the voltage should be gradually reduced to zero, to
discharge capacitors, before the test leads are disconnected.

3.5

Insertion

of

modules

and pcb

cards

These must not be inserted into or withdrawn from equipment whist it is
energised since this may result in damage.

3.6

Fibre optic

communication

Where fibre optic communication devices are fitted, these should not be
viewed directly. Optical power meters should be used to determine the operation
or signal level of the device.

4. OLDER

PRODUCTS

Electrical adjustments
Equipments which require direct physical ad ustments to their operating

mechanism to change current or voltage settings, should have the electrical
power removed before making the change, to avoid any risk of electrical shock.

Mechanical adjustments
The electrical power to the relay contacts should be removed before checking any

mechanical settings, to avoid any risk of electric shock.
Draw out case relays

Removal of the cover on equipment incorporating electromechanical operating
elements, may expose hazardous live parts such as relay contacts.

Insertion and withdrawal of extender cards
When using an extender card, this should not be inserted or withdrawn from the

equipment whilst it is energised. This is to avoid possible shock or damage
hazards. Hazardous live voltages may be accessible on the extender card.

Insertion

and

withdrawal

of heavy

current

test

plugs

When using a heavy current test plug, CT shorting links must be in place before
inserti

on or removal, to avoid potentially lethal voltages.

5.

DECOMMISSIONING

AND

DISP

OSAL

Decommissioning: The auxiliary supply circuit in the relay may include

capacitors across the supply or to earth. To avoid electric
shock or energy hazards, after completely isolating the supplies
to the relay (both poles of any dc supply), the capacitors should
be safely discharged via the external terminals prior to
decommissioning.

Disposal:

It is recommended that incineration and disposal to
water courses is avoided. The product should be disposed of in
a safe manner. Any products containing batteries should have
them removed before disposal, taking precautions to avoid
short circuits. Particular regulations within the country of
operation, may apply to the disposal of lithium batteries.

6. TECHNICAL SPECIFICATIONS

Protective fuse rating

The recommended maximum rating of the external protective fuse for this
equipment is 16A, Red Spot type or equivalent, unless otherwise stated in the
technical data section of the product documentation.

Insulation

class: IEC 601010-1 : 1990/A2 : 2001

Class

I
EN 61010-1: 2001
Class

I

This equipment requires
a protective (safety) earth
connection to ensure
user safety.

Insulation
Category
(Overvoltage):

IEC 601010-1 : 1990/A2 : 1995
Category III
EN 61010-1: 2001
Category III

Distribution level, fixed
insulation. Equipment in this
category is qualification
tested at 5kV peak,

1.2/50

µ

s,

500Ω, 0.5J, between all supply
circuits and earth and also
between independent circuits.

Environment:

IEC 601010-1 : 1990/A2 : 1995

Pollution degree 2
EN 61010-1: 2001

Pollution degree 2

Compliance is demonstrated
by reference to generic
safety standards.

Product Safety: 72/23/EEC

EN 61010-1: 2001
EN 60950-1: 2002

Compliance with the
European Commission Low
Voltage Directive.

Compliance is demonstrated
by reference to generic
safety standards.

Section 1. INSTALLATION

1.1 General

Protective relays, although generally of robust construction, require careful
treatment prior to installation and a wise selection of site. By observing a few
simple rules the possibility of premature failure is eliminated and a high
degree of performance can be expected.

The relays are either despatched individually or as part of a panel/rack
mounted assembly in cartons specifically designed to protect them from
damage.

Relays should be examined immediately they are received to ensure that
no damage has been sustained in transit. If damage due to rough
handling is evident, a claim should be made immediately to the transport
company concerned and the nearest General Electric representative should be
promptly notified. Relays which are supplied unmounted and not intended for
immediate installation should be returned to their protective polythene bags.

1.2 Unpacking
Care must be taken when unpacking and installing the relays so that none

of the parts are damaged or their settings altered and must at all times be
handled by skilled persons only.

Relays should be examined for any wedges, clamps, or rubber bands
necessary to secure m

oving parts to prevent damage during transit and these

should be removed after installation and before commissioning.
Relays which have been removed from their cases should not be left in

situations where they are exposed to dust or damp. This particularly
applies to installations which are being carried out at the same time as
constructional work.

1.3 Storage
If relays are not installed immediately upon receipt they should be stored in a

place free from dust and moisture in their original cartons and where de­humidifier bags have been included in the packing they should be retained.
The action of the de-humidifier crystals will be impaired if the bag has been
exposed to damp ambient conditions and may be restored by gently heating
the bag for about an hour, prior to replacing it in the carton.

Dust which collects on a carton may, on subsequent unpacking, find its way
into the relay; in damp conditions the carton and packing may become
impregnated with moisture and the de-humidifying agent will lose its efficiency.

The storage temperature range is –25° and +70°C.

1.4 Site
The installation should be clean, dry and reasonably free from dust and

excessive vibration. The site should preferably be well illuminated to facilitate
inspection.

An outline diagram is normally supplied showing panel cut-outs and hole
centres. For individually mounted relays these dimensions will also be found in
Publication R6008.

Publication R7012 is a Parts Catalogue and Assembly Instructions. This
document will be useful when individual relays are to be assembled as a
composite rack or panel mounted assembly.

9

Publication R6001 is a leaflet on the

modular

integrated drawout system of

protective relays.
Publication R6014 is a list of

recommended

suppliers for the pre-

insulated connectors.

Section

2. COMMISSIONING

2.1 Description of relay, calculation of setting and commissioning preliminaries

2.1.1 Description of MFAC 14/MFAC 34
This is a voltage operated relay having seven equally spaced settings of

15–185 volts, 25–175 volts, 25–375 volts or 100–400 volts which may be selected
by means of a plug bridge.

The relays may be used for any type of high impedance circulating
current protection.

2.1.2 List of abbreviations.
I

E

=

Current transformer

exciting current at relay setting voltage (referred to the

CT secondary current)

I

F

=

Maximum value of primary

through

fault current for which protection must

remain stable.

I

FM

=

Maximum value of primary fault current for internal fault.

I

P

=

Primary current for operation of protection.

I

R

=

Relay operating current.

I

SH

= Current

in

shunt

resistor at relay setting

VR.

N

= Turns

ratio of current transformer.

n

=

No. of current

transformers

in parallel with

relay.

R

CT

=

Secondary resistance of current transformer.

R

L

=

Lead resistance between

furthest

current

transformer

and relay

connection point.

R

R

=

Relay impedance.

R

SH

=

Value of

shunt

resistor.

V

F

=

The theoretical voltage which would be produced across the relay circuit

under internal fault condition.
V

F

=

I

FM (RCT

+

2RL +

RR) N

V

K

=

Knee point voltage of current transformer.

V

P

=

Peak voltage across relay circuit under

maximum

internal fault conditions.

V

S

=

Minimum

setting voltage. (calculated)

V

R

=

Relay setting voltage.

2.1.3 Calculation of relay setting.
The

minimum

setting voltage to ensure stability is

V

S

≥

I

F (RCT

+

2RL)

N

The relay plug setting voltage V

R

must

be set to the nearest tap above

VS.

10

The

minimum

knee point voltage

must

be

V

K

≥

2V

R

The operating current of the relay is 38mA, irrespective of tap selected, excluding
the current drawn by the external metrosil. When a standard

metrosil

is included

with the relay, the relay operating current including the

metrosil

is given in the table

below.
It

must

be appreciated that

metrosils

have large tolerances and these figures

are given for guidance only.

a) Low range relay (5V steps)

Setting voltage

V

R

15 50 75 100 125 150

175

185

Relay current

I

R

(mA)

38 38 39 42 46 55 72

81

(including metrosil, C = 450)

b) Low range relay

Setting voltage

V

R

25 50 75 100 125 150 175

Relay current

I

R

(mA)

19 19 20 23 27 36 53

(including metrosil, C = 450)

c) High range relay

Setting voltage

V

R

25 75 125 175 225 275 325

Relay current

I

R

(mA)

19 19 20 22 24 31 44

(including metrosil, C = 900)

d) 100–400V version

Setting voltage

V

R

100 150 200 250 300 350 400

Setting voltage IR(mA)

19 19 20 20 23 27 36

(including metrosil, C = 1100)

The primary current for operation is given by

I

P

=

N (I

R

+

n

I

E

)

If the

resultant

value of IP is too low it may be increased by the addition of a

shunt resistor R

SH

to give a current of

I

SH

= V

R

R

SH

The new increased value of primary current

I

P

=

N (I

R

+

nI

E

+

I

SH

)

External metrosils.
Each FAC relay is applied with an external

metrosil

which

must

be wired across

the relay circuit. This provides a

shunt

circuit for high internal fault currents and

prevents a high voltage being developed across the CT and relay circuits.

2.1.4 Commissioning preliminaries.
Inspection.
Carefully examine the module and case to see that no damage has occurred

during transit. Check that the relay serial number on the module, case and cover
are identical, and that the model number and rating information are correct.

Carefully remove any elastic bands/packing fitted for transportation purposes.
Carefully actuate the armature of each unit in turn with a small screwdriver/probe.

Note that immediately after the point where any normally open contacts just make

11

there is a small

further movement

of the

armature.

This ensures that contact follow

through

and wiping action is present. On units fitted with hand reset flag indicators,

check the flag is free to fall before, or just as, any normally open contacts touch.
Check that the external wiring is correct to the relevant relay diagram or

scheme diagram. The relay diagram

number

appears inside the

case.

Particular attention should be paid to the correct wiring and value of any external
resistors indicated on the wiring diagram/relay rating information.

Note that shorting switches shown on the relay diagram are fitted internally
across the relevant case

terminals

and close when the module is withdrawn. It is

essential that such switches are fitted across all CT circuits.
If a test block type MMLG is provided, the connections should be checked to the

scheme diagram, particularly that the supply connections are to the ‘live’ side of the
test block (coloured orange) and with

terminals

allocated with odd

numbers

(1, 3, 5,

7, etc.).
Earthing.
Ensure that the case earthing connection above the rear

terminal

block, is used

to connect the relay to a local earth bar.
Insulation.
The relay, and its associated wiring, may be insulation tested between:
a) all electrically isolated circuits
b) all circuits and earth
An electronic or brushless insulation tester should be used, having a dc voltage

not exceeding 1000V. Accessible

terminals

of the same circuit should first be

strapped together.
Deliberate circuit earthing links, removed for the tests, must subsequently be

replaced. Terminal allocation.
Terminals of the relay are normally allocated as below, but reference should

always be made to the relevant diagram.
a) Single pole relays

Normally open contacts 1, 3 and 2,

4.

AC current input – 27,

28.

An alternative version of the relay has additional normally open contacts
connected to 5, 7 and 6,

8.

b) Triple pole relays

Normally open contacts 1, 3 and 2, 4.
The contacts are normally connected in parallel for the three phases but

a version of the relay having contacts brought out separately is available.
AC current inputs - 23, 24 : 25, 26 : 27,

28.

2.2 Instructions to ensure that the relay can be commissioned at the specific
settings for the application

It is only necessary to check the relay at the setting on which it is to be used.
The relay

must

not be used at any setting other than that for which the setting has

been calculated.

12

2.2.1 Test

equipment

required

1 – Secondary injection test

equipment

capable of providing an ac voltage

supply of up to at least 120% of the relay setting.
1 – Multifinger test plug type MMLB 01 for use with test block type MMLG if fitted.
1 – Miniature split plug type MMLB 03 to fit relay plug bridge.
3 – Calibrated

multimeters

0–10 amp ac, 0–400 volt

ac.

1 – Set primary injection testing equipment.

2.2.2 General
If the relay is wired

through

an MMLG test block it is

recommended

that all

secondary injection tests should be carried out using this block.
Ensure that the main system current

transformers

are shorted before isolating the

relay from the current

transformers

in preparation for secondary injection tests.

DANGER:
DO NOT OPEN CIRCUIT THE SECONDARY CIRCUIT OF A CURRENT

TRANSFORMER SINCE THE HIGH VOLTAGE PRODUCED MAY BE LETHAL
AND COULD DAMAGE INSULATION.

When type MMLG test block facilities are installed, it is

important

that the sockets in

the type MMLB 01 test plug, which correspond to the current

transformer

secondary
windings, are LINKED BEFORE THE TEST PLUG IS INSERTED INTO THE TEST
BLOCK. Similarly, a MMLB 02 single finger test plug

must

be

terminated

with an

ammeter BEFORE IT IS INSERTED to

monitor

CT secondary currents.

It is assumed that the initial preliminary checks have been carried out.

2.2.3 Relay CT shorting switches
With the relay removed from its case, check electrically that the CT shorting switch

is closed.

2.2.4 Secondary injection testing
Connect the circuit as shown in Figure 1 and ensure that the current transformer

primary is open circuit and that if any earthing connections are fitted, they do not
short out the primaries of any current transformers.

Increase the voltage until the relay just operates.
Note the current in the relay (this can be done using the

miniature

split plug

inserted into the appropriate position of the plug bridge connected to an

ammeter).

It should be approximately 38mA at setting.
Note also the voltage at which the relay operates which should correspond to the

setting V

R

of the relay with a tolerance of ±10%. The total secondary current for

operation will be given on ammeter

A1. This test should be repeated for each pole

of the

relay.
Drop off/Pick up ratio.
Check that this ratio is greater than

50%.

13

2.2.5 Primary injection testing
It is essential that primary injection testing is carried out to prove the correct

polarity of current transformers.
Before

commencing

any primary injection testing it is essential to ensure that the

circuit is dead, isolated from the

remainder

of the system and that only those

earth connections associated with the primary test

equipment

are in position.

2.2.6 Primary fault setting
The primary fault setting of any balanced scheme can be checked using the circuit

shown in Figure 2. The primary current is injected into each current

transformer

in
turn and increased until the relay operates. The voltage at which the relay
operates should be within ± 10% of the relay setting voltage V

R

. The primary

current for operation and relay current should be noted.
In the case of machine protection similar tests

must

be carried out by injecting

first into each current

transformer

in turn to determine the primary fault setting.

For large machines the machine itself can be used to provide the fault current to
check the primary fault setting as shown in Figure 5. The machine should be run
up to speed with no excitation. The excitation should then be increased until the
relays have all operated. The primary c

urrent, relay current and relay voltage

should be noted as each relay operates.

2.2.7

Through

fault stability

With any form of unbalanced protection it is necessary to check that the current
transformers are correctly connected. For this purpose with a restricted earth
fault scheme the circuit shown in Figure 3 may be used. During this test it is
necessary to measure the spill current in the relay circuit and short out the relay
and stabilising resistor (if fitted). The current is increased up to as near full load
as possible and the spill current noted. The spill current should be very low, only
a few milliamps if the connections are correct. A high reading (twice the injected
current, referred through the current transformer ratio) indicates that one of the
current transformers is reversed.

Injection should be carried out through each phase to netural.
Where primary injection is not practicable in the case of restricted earth fault

protection on a

transformer

it may be possible to check stability by means of back

energising the

transformer

from a low voltage (415V) supply as shown in Figure 4.

In the case of machine protection, similar stability tests

must

be carried out

by

injecting into one and out of another current

transformer

connected on the same

phase.
For large machines, the machine itself can be used to provide the fault current,

but the short circuit

must

now be fitted as shown in Figure 6. The machine should

be run up to

normal

speed and the excitation increased until the primary current is

approximately full load, when the spill current should be checked.
All other types of balanced protection should be tested in a similar manner.
At the conclusion of the tests ensure that all connections are correctly restored

and any shorting connections removed.

14

Stabilising resistor (if fitted)

Relay

A2

A1

Metrosil

Ammeter
(in plug bridge circuit)

V

Figure 1 Secondary injection of relay to check secondary operating current, setting voltage and

relay operating current.

A1

Primary injection

test set

V

Stabilising resistor (if fitted)

A2

Relay

Ammeter (in plug

bridge circuit)

Figure 2 Sensitivity check of restricted earth fault scheme by primary injection.

15

A1

Primary injection

test set

A

B

C

Temporary connections

A2

Stabilising resistor (if fitted)

Relay

Metrosil

Figure 3 Stability check of restricted earth fault protection.

A1

A

LV

B

supply

C

Temporary short

circuit

A2

Stabilising resistor (if fitted)

Relay

Figure 4 Stability check on restricted earth fault scheme by back energising with a low voltage supply.

16

Temporary short

circuit

Generator

Isolating

links

A

B

C

V

87

87

87

87 Generator differential

relay

V

V

oltmeter

Figure 5 Testing sensitivity of generator differential protection using generator to supply

primary current.

Generator

Isolating

links

Temporary short

circuit

A

B

C

A2 A2

A2

87

87

87

87 Generator differential

relay

A2

Ammeter

Figure 6 Checking stability of generator differential protection.

17

Section

3. MAINTENANCE

Periodic

maintenance

is not necessary. However, periodic inspection and test is

recommended.

This should be carried out every l2

months

or more often if the relay is

operated frequently or is

mounted

in poor

environmental

conditions.

3.1 Repeat secondary injection tests 2.2.4 to prove operation, with emphasis on
contact wear and condition. Mechanical settings may be checked against those
shown in Section

4.

Section

4.

MECHANICAL

SETTINGS

4.1 General

Armature gap

measurements

should be made with the top of the feeler gauge

level with the centre line of the core.
Contact pressures are measured with a

gramme

gauge at the contact tips.

In general contact gaps and follow

through

are defined by quoting an

armature

gap

at which the tips should be just closed or just open.
The relay contact state is always defined with the relay in the unenergised

position, unless otherwise specified on the appropriate circuit diagram.

4.1.1 With the

armature

closed the clearance between the back of the

armature

and

the back stop should be

0.003"/0.008".

4.1.2 Nominal

armature

gap open: 0.060" for all

types.

Set screw in

armature

so that

armature

gap when closed is approximately

0.005"/0.010".

4.2 Contact settings

4.2.1 Normal duty make contacts
With the

armature

closed onto a 0.011" feeler gauge the make contacts should be

closed, but should be open using a 0.013" feeler gauge.

Contact settings

2 contacts
(MFAC

34)

4 contacts
(MFAC

14)

Force to just close the
make contacts

20/25 grams 15/20 grams

Force to just lift the fixed
contact off its support

15/20 grams

20/25 grams

Nominal contact gap

0.060"/0.080"

4.3 Mechanical flag settings

4.3.1 Settings for self reset units
MFAC

l4/34

With the armature closed on to a 0.013" feeler gauge the flag should be free to fall,
but should not fall using an 0.018" feeler gauge. Adjustment is made to the catch
spring on the flag.

18

Section

5.

PROBLEM

ANALYSIS

5.1 Failure to operate

Check diagram for correct input connections.
Check tap voltage; this is

marked

above or below the plug bridge on the front of the

module.
Note: with the plug removed the relay setting goes to the highest tap value.

Measure the input current at VS, this should be 38mA (excluding the
metrosil).

Flag spring may be

jammed

between

armature

and core face, preventing armature

closure.
Check internal wiring for damage.
Check choke continuity - resistance 240

ohms ±

15%.

Check resistor values - remove pcb from module and fold down to gain access
to board.

Setting range Resistors on PCB ZJ0038

R1 – R3 R5–R6 R7–R8

R9

15–185 680Ω 680Ω 150Ω

120

Ω

Adjustable resistor

0–1000

Ω

Capacitor

3.3µF

Relay coil

190

Ω

Setting range Resistors on PCB ZJ0038

R1 –

R6

25–175

1.3K

Ω

25–327

2.4K

Ω

Adjustable resistor RV1

510

Ω

Capacitor C1

1.7

µ

F

±5% 50Hz,

1.18

µF ±5%

60Hz.

Relay coil 560Ω ±

15%

Setting range Resistors on PCB ZJ0038

R1–R6

100–400

2.7K

Ω

R9

3.9K

Ω

5.2 Output contacts not changing state

Check output

terminals

with reference to appropriate diagram.
Operating pushrods not in position
Internal

wiring damaged

Contamination

of contacts
Contacts should be cleaned with the burnishing tool supplied in the relay tool kits.
On no account should knives, files or abrasive materials be used.
Check mechanical settings as per Section

4.

19

Section 6. SPARES

When ordering spares, quote the full relay model number and any component
reference numbers, or briefly describe the parts required.

Should the need arise for the equipment to be returned to General Electric for
repair please fill in the RMA form at the back of this manual.

A copy of any commissioning test results should also be sent with the
equipment.

20

Section

7.

COMMISSIONING TEST

RECORD

High Impedance

Differential

Relay Type

MFAC

Date

Station

Circuit.

Relay Model

No.

Serial

No.

Setting range

CT ratio

Setting voltage

Relay setting

Type of ext. metrosil

Shunt resistor ohms

(if fitted)

Calculated primary

operating current

Test results

2.2.3 Relay CT shorting

switch

2.2.4 Secondary voltage to operate

relay.

Phase

Total current

(A1)

Relay current

(A2)

PU volts

DO volts

A

B

C

Drop off / pick up ratio check

2.2.6 Primary current to operate relay

Phase

Primary current

(A1)

Relay current

(A2)

Relay voltage

A

B

C

N

21

2.2.7 Stability check by primary injection
Restricted earth fault

Phases Primary current

(A1)

Spill current

(A2)

A–N

B–

N

C–N

Circulating current between two or more sets of current transformers.

Phases Primary current

(A1)

Spill current

(A2)

A1–A2

B1–B2

C1–C2

Where more than two sets of current

transformers

are involved, injection should

be carried out between set 1 and each other set in turn.

Commissioning

Engineer

Customer

Witness

Date Date

22

Page 1 of 2

REPAIR / MODIFICATION RETURN AUTHORIZATION FORM – RMA FORM

FIELD ONLY TO BE FILLED IN BY A GE GRID Automation REPRESENTATIVE

RMA Reference

Date :

ACT Reference (M):

Repair Center address to Ship the Unit:

UK Grid Solution LTD
St Leonards Building
Harry Kerr Drive,
Redhill Business Park,
Stafford,
ST16 1WT, UK
FAO :- After Sales Department

GE GRID Automation Local Contact Information:
Name of Contact - Tel No - email –

1. IDENTIFICATION OF UNIT & FAULT INFORMATION - Fields marked (M) are mandatory, delays in return will occur if not completed.

Qty

Type of Material(M)
Model N° (M)

Serial

n°(M)

Part n°(M)

SW

Vers

Description of Fault or Modification required(M)

Are Field

Volts
Used (M)

Warranty

Y/N ?

(M) Equipment failed during Installation / Commissioning Yes

Equipment failed during service Yes How long?

(M) Equipment failed during Installation / Commissioning Yes

Equipment failed during service Yes How long?

2. SPECIALIST REPAIR INSTRUCTIONS

Do you want an updated firmware version after repair? Yes No

Is the relay being returned in a case? Yes No (If No see repair Term 5)

3. CUSTOMS & INVOICING INFORMATION REQUIRED TO ALLOW RETURN OF REPAIRED ITEMS

Value for Customs (M):

Customer Invoice Address if paid (M)

Customer Return Delivery Address (full street address) (M)

Part Shipment Accepted (Yes/No) –

Contact Name:

Tel No:

Email:

Contact Name:

Tel No:

Email:

4. REPAIR TERMS & CONDITIONS

1. Please ensure a copy of the import invoice is attached with the returned unit/Airwaybill document copy emailed (M)

2. Please ensure the Purchase Order is released, for paid service, to allow the unit to be shipped

3. Submission of equipment to UK Grid Solutions is deemed as authorization to repair and acceptance of quote.

4. Please ensure all items returned are marked as Returned for ‘Repair/Modification’ and protected by appropriate packaging (anti-static

bag for each board / relay with foam protection).

5. If a relay is not being returned in a case, please refer to instructions on Page 2.

Page 2 of 2

5. Return Packaging Standards (ALL PRODUCTS)

1. Please ensure the device is clean, no sharp edges are exposed and the device is in

a suitable condition to be handled.

2. Relay’s returned without cases should be placed in to Anti-Static Bags and sealed

to protect hyper-sensitive components.

3. A suitable size box should be used, with packing material at the bottom, the

device placed into box with sufficient gaps to fill with packing material around
each side and on the top, extra packaging material placed around the relay.

4. Please include a copy of the completed RMA form then close the lid and seal with

packaging tape.

5. The relay should then be secondary packed if being exported, the primary

packed box should be placed into an oversized box with packaging
material surrounding the primary packed box and then sealed.

Imagination at work

Grid Solutions
St

Leonards Building

Redhill Business Park
Stafford, ST16 1WT, UK
[phone]
www.gegridsolutions.com/contact

© 2017 General Electric. All rights reserved. Information contained in this document is indicative only.
No representation or warranty is given or should be relied on that it is complete or correct or will apply to any particular

project.

This will depend on the technical and commercial circumstances. It is provided without liability and is subject to

change without notice.

Reproduction, use or disclosure to third parties, without express written authority, is strictly prohibited.

R8007H