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GE MFAC 14 User Manual Download Page 17

 

 

 

Temporary short circuit 

 

 

Generator 

Isolating 

links 

A 

B 

C 

 

 

 

 

 

 

 

 

 

 

V 

87 

87 

87 

 

 

87    Generator differential relay 
V  Voltmeter 

 

 

 

 

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 

Summary of Contents for MFAC 14

Page 1: ...GE Energy Connections Grid Solutions MFAC 14 34 User Manual High Impedance Differential Relay Publication reference R8007H ...

Page 2: ......

Page 3: ...s 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 ...

Page 4: ...ssioning 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 ...

Page 5: ... 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 ...

Page 6: ...rotection 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 resisto...

Page 7: ...e 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 ...

Page 8: ...gory 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...

Page 9: ...ioning 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 ...

Page 10: ...protection must remain stable IFM Maximum value of primary fault current for internal fault IP Primary current for operation of protection IR Relay operating current ISH Current in shunt resistor at relay setting VR N Turns ratio of current transformer n No of current transformers in parallel with relay RCT Secondary resistance of current transformer RL Lead resistance between furthest current tra...

Page 11: ...g voltage IR mA 19 19 20 20 23 27 36 including metrosil C 1100 The primary current for operation is given by IP N IR nIE If the resultant value of IP is too low it may be increased by the addition of a shunt resistor RSH to give a current of ISH VR RSH The new increased value of primary current IP N IR nIE ISH External metrosils Each FAC relay is applied with an external metrosil which must be wir...

Page 12: ...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 re...

Page 13: ...ings 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 close...

Page 14: ...k 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...

Page 15: ...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 ...

Page 16: ...tor 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 ...

Page 17: ...Voltmeter 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 ...

Page 18: ...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 ma...

Page 19: ... access to board Setting range Resistors on PCB ZJ0038 R1 R3 R5 R6 R7 R8 R9 15 185 680Ω 680Ω 150Ω 120Ω Adjustable resistor 0 1000Ω Capacitor 3 3µF Relay coil 190Ω Setting range Resistors on PCB ZJ0038 R1 R6 25 175 1 3KΩ 25 327 2 4KΩ Adjustable resistor RV1 510Ω Capacitor C1 1 7µF 5 50Hz 1 18µF 5 60Hz Relay coil 560Ω 15 Setting range Resistors on PCB ZJ0038 R1 R6 100 400 2 7KΩ R9 3 9KΩ 5 2 Output c...

Page 20: ...onent 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 ...

Page 21: ...ting 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 ...

Page 22: ... 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 23: ...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 Co...

Page 24: ...e 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 s...

Page 25: ...n 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 pr...

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