Areva MCAG 19 User manual

Types MCAG 19, 39
Protective Relays
Service Manual
R8035F

Page 2
CONTENTS
1. INSTALLATION 3
1.1 General 3
1.2 Unpacking 3
1.3 Storage 3
1.4 Site 3
2. COMMISSIONING 4
2.1 General 4
2.2 Electrostatic discharges 4
2.3 Wiring 4
2.4 Commissioning preliminaries 4
2.5 Insulation 5
2.6 Earthing 5
2.7 Main current transformers 5
2.8 Equipment required 5
2.9 Electrical tests 5
2.10 Output Contacts 6
3. MAINTENANCE 6
4. MECHANICAL SETTINGS 6
4.1 General 6
4.2 Contact setting 7
4.3 Mechanical flag setting 7
5. PROBLEM ANALYSIS 7
5.1 Failure to operate 7
5.2 Operating at the incorrect values 8
5.3 Output contacts 8
5.3.1 Output contacts not operating mechanically 8
6. SPARES 8
7. COMMISSIONING TEST RECORD 9
REPAIR FORM 11

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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 the 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
GEC ALSTHOM T&D Protection & Control 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 form 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 in to 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
R6035.
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.

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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 form 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 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.

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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, subsequently must
be replaced.
Disconnect the external wiring from the appropriate case terminals to low
application of the test supply.
Consult the appropriate application diagram for the case terminals
FIMCAG11 001 for MCAG19/39 relays
FIMCAG31 001 “ “ “ “ “
The relay ratings and settings are indicated on the front of each module.
2.6 Earthing
Ensure that the case earthing screw is used to connect the relay to a local earth.
2.7 Main current transformers
Do not open the secondary circuit of a live ct, since the high voltage produced may
be lethal to personnel and could damage insulation.
2.8 Equipment required
A current source capable of supplying sinusoidal current at the appropriate test
current levels.
An ammeter with the appropriate current range.
2.9 Electrical tests
Set the plug bridge to its lowest value.
Set xIspotentiometer to 1.
Slowly raise the current until the relay picks up.
The relay contacts should switch cleanly with no chatter of the contacts, and be
relatively quite.
The mechanical flag should fall as or just before the contacts operate.
Reduce the current slowly and the relay should reset.
Repeat this procedure several times to ensure consistency, resetting the mechanical
flag after each operation.
Pick up tolerance ±5% of Is
Reset value >80% of Is
Repeat this test for each of the calibration marks of the xIspotentiometer
Set the plug bridge to its highest value and repeat above for calibrated values xIs
potentiometer.
Remove plug from plug bridge and check that the setting is at its highest plug bridge
setting.

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2.10 Output Contacts
Check that the output contacts close or open as appropriate.
Replace the cover and ensure that the cover reset mechanism will reset the
mechanical flag.
Connect the relay to the system as shown in the application diagram.
Replacing any links, wiring, fuses and remove any ct short circuits used during
commissioning.
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.
Routine testing of the relay can be performed by the secondary injection method,
as detailed in the commissioning instructions, Section 2.
Mechanical setting should be checked as per Section 4, and if any adjustment is
made, then Section 2 should be repeated.
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 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.
Contact Type Symbol used on diagrams
Normal duty
Make
(normally open) M
Break
(normally closed) B
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 0.070"/0.080".
Nominal armature gap closed 0.070"/0.025"-adjustment by setting screw in
armature, lock and varnish after setting.

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4.2 Contact setting
Normal duty make and break contacts.
With the armature closed onto a 0.012" feeler gauge the make contact should be
closed, but should be open using a 0.015" feeler gauge.
Force to just close the make contacts 18/23 grams.
Make contact gap 0.070"/0.080".
Force to just open the break contacts 15/20 grams.
Break contact gap 0.060"/0.070".
The gap between the top of the armature and the make moving contact should be
0.130 minimum when the flag is down.
Relays with four pairs of hands reset contact.
It will be necessary to remove the force of the upper contacts from the measuring the
appropriate contact force.
Also with the flag down the force to just move the armature off the backstop should
be 60/80 grams. This force is measured at the end of the armature and is adjusted by
the screw which is located between the contact blades near to the contact blocks.
Contact settings for:
Normal duty make and break short hand reset contacts.
4.3 Mechanical flag setting
With the armature closed onto a 0.015" feeler gauge the flag should be free to fall,
but should not fall using a 0.020" feeler gauge.
Adjustment is made to the catch spring on the flag.
Section 5. PROBLEM ANALYSIS
5.1 Failure to operate
Check diagram for correct input connections. Check value of Is, the value is marked
on the module front plate over the plug bridge. The potentiometer (xIs) is a
multiplier for the plug setting.
Check internal wiring for loose or damaged joints.
Flag spring may be distorted holding the armature open.
Push rods not correctly located.
Check value of potentiometer RV1 (4.7K ohms +10%) and that its value can be
adjusted.
Check value of R1 (1K ohms +5%).
Check continuity of T1 secondary/primary (check both plug taps).
Check continuity of relay coil (2640 ohms ±10%).
Check diodes D1 and D4 on the pcb Zg 0891 for open or short circuit.

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5.2 Operating at the incorrect values
Check plug settings, and xIssettings.
Check knob on xIs, the dot on the potentiometer skirt should be in line with the
setting mark when the potentiometer os rotated fully anticlockwise.
Check mechanical settings-see Section 4.
Check values and adjustment of potentiometer, this can be damaged if overloads are
left on too long. See Publication R6035 for ratings.
Current supply not sinusoidal.
Inaccurate ammeter.
5.3 Output contacts
Contacts making mechanically, but open circuit at case terminals.
Check wire diagram.
Check connections to module terminal block and relay contacts.
Contacts contaminated- these should be cleaned with a burnishing tool, supplied in
relay tool kits
On on account should knifes, files or abrasive materials be used.
Check mechanical settings as per Section 4.
5.3.1 Output contacts not operating mechanically
Push rods not correctly located.
Check electrical connections.
Flag spring may be distorted holding the armature open
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 GEC ALSTHOM T&D
Protection & Control Limited for 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.

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Section 7. COMMISSIONING TEST RECORD
Type MCAG Current Relay Single and Three Phase
Site ______________________________ Circuit ____________________________
Model No._________________________ Serial No.__________________________
Rating: ___________________________ Aux ______________________________
Diagram __________________________ Setting ____________________________
1. Pick up check
Phase Setting Operate current
A
B
C
Delete if not applicable
1.1 Check reset (drop off) is >80% of Is __________
2. Check flag indicator __________
3. Check contact operation __________
4. Remarks
___________________________________ ____________________________________
Commissioning Engineer Customer Witness
___________________________________ ____________________________________
Date Date

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continued overleaf
✁
REPAIR FORM
Please complete this form and return it to GEC ALSTHOM T&D Protection & Control
Limited with the equipment to be repaired. This form may also be used in the case of
application queries.
GEC ALSTHOM T&D Protection & Control Limited
St. Leonards Works
Stafford
ST17 4LX,
England
For: After Sales Service Department
Customer Ref: __________________ Model No: _________________
GECA Contract Ref: __________________ Serial No: _________________
Date: __________________
1. What parameters were in use at the time the fault occurred?
AC volts _____________ Main VT/Test set
DC volts _____________ Battery/Power supply
AC current _____________ Main CT/Test set
Frequency _____________
2. Which type of test was being used? ________________________________________
3. Were all the external components fitted where required? Yes/No
(Delete as appropriate.)
4. List the relay settings being used
______________________________________________________________________
______________________________________________________________________
______________________________________________________________________
5. What did you expect to happen?
______________________________________________________________________
______________________________________________________________________
______________________________________________________________________
______________________________________________________________________

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✁
6. What did happen?
______________________________________________________________________
______________________________________________________________________
______________________________________________________________________
______________________________________________________________________
7. When did the fault occur?
Instant Yes/No Intermittent Yes/No
Time delayed Yes/No (Delete as appropriate).
By how long? __________
8. What indications if any did the relay show?
______________________________________________________________________
______________________________________________________________________
______________________________________________________________________
9. Was there any visual damage?
______________________________________________________________________
______________________________________________________________________
______________________________________________________________________
10. Any other remarks which may be useful:
______________________________________________________________________
______________________________________________________________________
______________________________________________________________________
___________________________________ ____________________________________
Signature Title
___________________________________ ____________________________________
Name (in capitals) Company name

A
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Publication: R8035F