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.