Areva MVAG User manual

Type MVAG
Instantaneous Under and
Over Voltage Relays
Service Manual
R8049D

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 AREVA T&D 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 long 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.
AREVA T&D 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.

Page 4
Types: Single Triple
Element Element
Undervoltage
MVAG 11 MVAG 31
MVAG 12 MVAG 32
MVAG 13 MVAG 33
MVAG 14 MVAG 34
Overvoltage
MVAG 15 MVAG 35
MVAG 16 MVAG 36
MVAG 17 MVAG 37
MVAG 18 MVAG 38
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 General 10
2.2 Electrostatic discharges 10
2.3 Wiring 10
2.4 Commissioning preliminaries 10
2.5 Insulation 11
2.6 Wiring 11
2.6.1 Relay types 11
3. MAINTENANCE 12
4. MECHANICAL SETTINGS 12
4.1 Contact setting 12
4.2 MVAG relays 12
4.3 Mechanical flag settings 13
4.3.1 Hand reset flag 13
5. PROBLEM ANALYSIS 13
5.1 General 13
5.2 Failure to operate/reset 13
5.3 Failure of output contacts to change site. 14
5.4 Incorrect operating/resetting values. 14
6. SPARES 14
7. COMMISSIONING TEST RECORD 31
REPAIR FORM 33

CONTENT
1. SAFETY SECTION 3
1.1 Health and safety 3
1.2 Explanation of symbols and labels 3
2. INSTALLING, COMMISSIONING AND SERVICING 3
3. EQUIPMENT OPERATING CONDITIONS 4
3.1 Current transformer circuits 4
3.2 External resistors 4
3.3 Battery replacement 4
3.4 Insulation and dielectric strength testing 4
3.5 Insertion of modules and pcb cards 4
3.6 Fibre optic communication 5
4. OLDER PRODUCTS 5
5. DECOMMISSIONING AND DISPOSAL 5
6. TECHNICAL SPECIFICATIONS 6

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 Explanation 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 GROUND.
2. INSTALLING, COMMISSIONING AND SERVICING
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 2.5mm2, 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 resistors
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 adjustments 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
insertion or removal, to avoid potentially lethal voltages.
5. DECOMMISSIONING AND DISPOSAL
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, 1.2/50µs,
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.

Page 9
Section 1. INSTALLATION
1.1 General
Protective relays, although generally of robust construction, require careful treatment
prior to installation. 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 to the transport company concerned immediately, and
AREVA T&D 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 setting altered, and must be handled by skilled persons at
all times.
Relays should be examined for any wedges, clamps, or rubber bands necessary to
secure moving 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 is particularly applies to installations
which are being carried out at the same time as construction 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 de-humidifier 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 ambient
conditions and may be restored by gently heating the bag for about an hour, prior to
placing 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°C to +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
R6049.
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.

Page 10
Publication R6001 is a leaflet on the modular integrated drawout system
Publication R6014 is a list recommended suppliers for the pre-insulated connectors.
Section 2. COMMISSIONING
2.1 General
Before leaving the factory all relays are accurately adjusted, tested and carefully
packed. Hence there should be no need for any re-adjustment on commissioning.
Moving parts are held in position during transit by rubber bands and packing.
These should be removed carefully.
2.2 Electrostatic discharges
The relay uses components which are sensitive to electrostatic discharges.
When handling the module, care should be taken to avoid contact with components
and electrical connections. When removed from the case for storage, the module
should be placed in an electrically conducting anti-static bag.
2.3 Wiring
Check that ratings of relay agree with the supplies to which it is to be connected.
Check all wiring connections to the relay, including the case earthing connection
above the terminal block. It is especially important that dc supplies and magnetic
blowout contacts are wired with the correct polarity. The relay diagram number
appears inside the case.
2.4 Commissioning preliminaries
To gain access to the relay, first loosen the captive cover screw and carefully remove
the cover from the case.
The module can then be removed from the case by grasping the handles at the top
and bottom of the front plate and pulling forwards.
Care must be taken to ensure that mechanical settings of the element are not
disturbed.
Carefully remove the rubber band securing the flag mechanism.
Check that the bottom end of the contact operating card has not been dislodged from
the slot in the armature extension and that the ends of the push rods are located in
the holes in the contact springs.
Carefully actuate the armature of each unit in turn with a small screwdriver/probe.
Note immediately after the point where any make contacts just close there is a further
small movement of the armature. This ensures that contact follow through and wiping
action is present. Repeat similarly with break contacts on armature release.
On units fitted with hand reset flag indicators, check that the flag is free to fall before,
or just as, any make contacts close.
Replace the module in the case and refit the cover. Make sure that the reset
mechanism in the cover is correctly located with respect to the relay element, and that
the flag (or mechanism) can be reset.

Page 11
2.5 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.
2.6 Wiring
Check operation by energising the relay with ac or dc voltage levels as appropriate.
The appropriate terminals should be identified from the internal wiring diagram
normally supplied.
On the following types, apply rated auxiliary supply voltage (Vx) to terminals 13
and 14.
MVAG 12/32, 14/34, 16/36, 18/38.
On all types, apply measuring supply (Vn) to the appropriate relay terminals and
check pick up values.
2.6.1 Relay types
MVAG 11/31, 12/32, 15/35 and 16/36 have fixed settings.
MVAG 13/33, 14/34, 17/37 and 18/38 have adjustable settings.
Operate levels for all types should be within ±5% of their set values.
Reset levels vary with type:
MVAG 11/31 U/V nominally 90% of Vn
12/32
MVAG 13/33 U/V nominally 140% of Vs
MVAG 14/34 U/V nominally 110% of Vs
MVAG 15/35 O/V nominally 70% of Vs
17/37
MVAG 16/36 O/V nominally 90% of Vs
18/38
Disconnect external wiring from these terminals to allow application of the test
supply.
The relay should switch cleanly with one movement.
Vs, Vnand Vxare marked on either the lower handle strip or front plate.
Restore any external wiring connections that may have been disturbed during the
above tests.

Page 12
Section 3. MAINTENANCE
Periodic maintenance is not necessary. However, periodic inspection and test is
recommended. This should be carried out every 12 months or more often if the relay
is operated frequently or is mounted in poor environmental conditions.
Check mechanical settings as per Section 4.
Tests 2.5 and 2.6 should be carried out to prove operation.
Section 4. MECHANICAL SETTINGS
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 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. Some mechanically operated
contact gap must be measured directly with feeler gauges at the contact tips.
The relay contact state is always defined with the relay in the unenergised position,
unless otherwise specified on the appropriate circuit diagram.
Contact type Symbol used on diagrams
Normal duty
Make M
(normally open)
Break B
(normally closed)
With the armature closed the clearance between the back of the armature and the
back stop should be 0.003"/0.008"
Nominal armature gap open 0.050"/0.060" for all types.
4.1 Contact setting
MVAA relays used as follower relays on the following MVAG types:
MVAG 12/32, 14/34, 16/36, 18/38.
Normal/heavy duty make and break contacts.
With the armature closed onto a 0.011" feeler gauge the make contacts should be
closed, but should be open using 0.013" feeler gauge.
With the armature closed onto a 0.027" feeler gauge the break contact should be
open, but should be closed using a 0.029" feeler gauge.
Force to just close the make contacts 20/25 grams.
Force to just open the break contacts 18/23 grams.
4.2 MVAG relays
Normal duty make and break contacts.
With the armature closed onto 0.012" feeler gauge the make contacts should be
closed, but should be open using a 0.015" feeler gauge.

Page 13
With armature closed onto a 0.040" feeler gauge the break contact should be open,
but should be closed using a 0.043" feeler gauge.
Force to just close the make contacts 15/20 grams
Force to just open the break contacts 15/20 grams
The armature is fitted with a screw, adjustment of this screw affects the drop off
value. The screw must protrude by 0.003"/0.008". Adjustment of the screw also
changes the follow through, and this must be rechecked after adjustment of the
screw.
Excessive protrusion of the screw will result in poor contact action.
Contact gaps 0.070"/0.080".
The pick up is controlled by the contact forces, and by the force applied to the
armature by the spring. Adjustment of the spring is by a screw adjustment between
the pairs of contacts.
The lock nuts of the armature screw and contact setting screw must be varnished after
adjustment.
4.3 Mechanical flag settings
Mechanical flags can be fitted to all relays, however the flag is fitted to the
measuring element for the following types:
MVAG 11/31, 13/33, 15/35 and 17/37.
and to the following MVAA element on the following types:
MVAG 12/32, 14/34, 16/36 and 18/38.
4.3.1 Hand reset flag
With the armature closed onto a 0.018" feeler gauge the flag should be free to fall,
but should not fall using a 0.013" feeler gauge.
Adjustment is made to the catch spring on the flag.
Section 5. PROBLEM ANALYSIS
5.1 General
Check diagram for the correct input connections. Check values of Vn, Vxand Vsare
correct, these are marked on the front of the module.
5.2 Failure to operate/reset
Flag spring may have been distorted and is holding the armature open or closed.
Check internal wiring:
Connections to terminal block
Connections to pcb - when fitted.
On relays with adjustable settings - chek setting value.
Auxiliary supply (Vx) not applied to terminals 13 and 14, MVAG 12/32, 14/34,
16/36 and 18/38.
Check series resistors and rotary switches (where appropriate).
Check wiring of internally wired contacts and their contact settings.
Rectifier bridge faulty.

Page 14
5.3 Failure of output contacts to change site.
Operating card/push rods not in position.
Check output terminals with reference to diagram.
Contamination of contacts.
Contacts should be cleaned with the burnishing tool, supplied in relay tool kits.
On no account should knives, files or abrasive materials be used.
Check mechanical settings as per Section 4.
5.4 Incorrect operating/resetting values.
Switch knob may have slipped. This can be reset as follows:
Turn the knob fully anti-clockwise. Remove the blue plastic cap in the switch knob.
Loosen screw and align arrow on the knob with the lowest setting. Tighten screw and
refit plastic value.
Note: The switch used is a 12 position switch and can, therefore, be rotated past
the highest setting. In the unmarked positions the relay is set to its highest
setting value.
Check switch setting (if appropriate).
Check values and correct connection of any external series resistors.
Check mechanical settings as per Section 4.
Section 6. SPARES
When ordering spares, quote the full relay model number and any component
reference numbers, or briefly describe the parts.
Repairs
Should the need arise for the equipment to be returned to AREVA T&Dfor repair, then
the form at the back of this manual should be completed and sent with the equipment
together with a copy of any commissioning test results.

Page 15
Figure 1: Circuit diagram: MVAG 11 undervoltage relay
Viewed from front
21 43
RL1
2
R2 R1
3
12
4
C1
28
D4 D3
D2 D1
RVD1
27
Vn
Note 1 (a) CT shorting links make
before (b) and (c) disconnect.
(b) Short terminals break before (c). (c) Long terminals
1 2 3 4
56 13 14
21 22 27 28
Case earth
Module terminal block
viewed from rear
Combinations of Output contacts to
output contacts module terminals
1 3 2 4
2M –MM 1M 1B M B
Contact description
M : Make B : Break
ZJ0075

Page 16
Figure 2: Circuit diagram: MVAG 12 undervoltage fixed setting
Note 1 (a) CT shorting links make
before (b) and (c) disconnect.
(b) Short terminals break before (c). (c) Long terminals
Rear unit –RL2
Combinations of Output contacts to
output contacts module terminals
10 12
1M –M
Contact description
M : Make B : Break
Rear mounted
facing rear
viewed from front
10 12
RL2
1
R3
R2
2
910
8
C1
28
D3 D4
D1 D2
RVD1
Vn
RL1–A
R1
7
27
A
Front mounted
facing front
viewed from front
1 3
25 47 69 811
RL1
5
Rext R4
5
3
6
4
14
D7 D8
D5 D6
RVD2
13
Vx
1 2 3 4 56 78 910
11 12 13 14 21 22 27 28
Case earth
Module terminal block
viewed from rear
RL2–A
A
Front unit –RL1
Combinations of Output contacts to
output contacts module terminals
1 3 5 7 9 11 2 4 6 8
5M –MMMMM 4M 1B B M M M M 3M 2B B M M B M 2M 3B B B M B M 1M 4B B B M B B
–5B B B B B B
ZJ0073
Part Board
ZJ0073
Part Board 1

Page 17
Figure 3: Circuit diagram: MVAG 13 undervoltage relay
21 43
Combinations of Output contacts to
output contacts module terminals
1 3 2 4
2M –MM 1M 1B M B
Contact description
M : Make B : Break
Viewed from front
RL1
2
D2 D4
D1 D3
RVD1
5
C1
6
R8
7
R7
6
R6
5
R5
4
R4
3
R3
2
R1
1
S1 13
1 2
Vn
27
28
1 2 3 4
56 13 14
21 22 27 28
Case earth
Module terminal block
viewed from rear
Note 1 (a) CT shorting links make
before (b) and (c) disconnect.
(b) Short terminals break before (c). (c) Long terminals
ZJ0071

Page 18
Figure 4: Circuit diagram: MVAG 14 undervoltage relay
1 2 3 4
56 13 14
21 22 27 28
Case earth
Module terminal block
viewed from rear
7 8
910
11 12
ZJ0071
9 11
Rear mounted
facing rear
viewed from front
RL2
1
D2 D4
D1 D3
RVD1
5
C1
6
R8
7
R7
6
R6
5
R5
4
R4
3
R3
2
1
S1 13
1 2
Vn
27
28
D6 D8
D5 D7
RVD1
3 4
13
14
R2
ZG0878
Part board
Vn
R1
ZG0878
Part board
7 8
RL1–A
RBK
W
21 43 65 87 10 12
Front mounted
facing front
viewed from front
RL1
5
RL2–A
A
A
Rear unit –RL2
Combinations of Output contacts to
output contacts module terminals
9 11
1M –M
Contact description
M : Make B : Break
Front unit –RL1
Combinations of Output contacts to
output contacts module terminals
1 3 5 7 2 4 6 810 12
5M –MMMMM
4M 1B M M B M M 3M 2B B M B M M 2M 3B B M B B M 1M 4B B B B B M
–5B B B B B B
Note 1 (a) CT shorting links make
before (b) and (c) disconnect.
(b) Short terminals break before (c). (c) Long terminals