Commissioning

Commissioning & Maintenanceof Protective Relays

Test Options (1)

1. Primary injection sensitivity tests only

Minimum of time consumed

If results incorrect, secondary injection and CT tests requiredUnable to check :-

a. Adequate timing curves

b. Directional properties

c. Power and impedance relays

Not suitable for maintenance tests

Test Options (2)

2. Secondary injection tests(But with C.T.’s still connected)

True primary sensitivity easily equated

If results incorrect isolated relay and CT mag. curve checks necessary

Ref. for maint., but system outage required

Primary tests on C.T. ratio and polarity still required on commissioning

Test Options (3)

3. Secondary injection tests(But with relays isolated by test facility)

Proof of isolated relay characteristic obtained

Ref. for maintenance obtained(relay if necessary tested with system on load)

Full primary injection/on load tests done oninitial commissioning only

Test Options (4)

4. On load tests

Checks that expected C.T. / V.T. quantitiespresent at test facility

Scheme stability for external faults

Proof of correct directional characteristics

Summary

Areva’s preference:-

1. Secondary injection (isolated relay)

2. Primary injection (incl. C.T. ratio, phasing and mag. curve)

3. On load tests

Site Testing and Commissioningof Protection Equipment

To assure ourselves, and the interested authorities, that the overall protective system functions correctly

Resist pressures to take risks

Study wiring diagrams and protection requirements

Key diagram

Delegate responsibilities

Observe safety of self and others

Commissioning Flow ChartSummary (1)

To assure ourselves, and the interested authorities, that the overall protective system functions correctly.

Study of wiring diagrams and protection requirements.

Careful delegation of responsibilities to reduce the duplication of effort and to ensure that all the following aspects are covered :-


Insulation Tests

Secondary Injection Tests (Relay Tests)

Ensure clean dust free areaMechanical inspectionOut-going contact wiringExternal resistorsC.T. shorting and isolating switchesContact follow-through and pressuresElectrical checks on each basic electrical function to

prove satisfactory operationProve trip and alarm circuitsTest results (record and maintenance purposes)


Primary injection tests

D.C. flick tests on C.T.’s

C.T. mag curve tests

C.T. ratio and polarity tests

Primary sensitivity tests

Stability tests

Test results


Line / Transformer / Generator energisation

V.T. ratio and phasing tests

On load testsStability testsDirectional properties

At the end of each stage ask yourself :-

Is there anything wrong, wiring or otherwise, that I have not checked that may prevent correct operation?

If so, CHECK IT OUT !

Peak 1.6 x AV.

Average D.C.

0V.

Peak to Peak V

<12% of mean D.C. comp.0V.

Mean D.C.

Measuring instrumentsD.C. auxiliary supplies

Faulty relays

Maintenance ofProtective Relays (1)

Frequency of Maintenance

Dictated by :-

a) The site condition

b) The availability of maintenance staff and resources

c) The availability of plant outage times

d) The risks involved if the protection should fail

e) The type of relay construction


Frequency of Maintenance (continued)

f) The proven reliability of devices under identical site conditions

g) The availability of built-in self-check features or semi-automatic test facilities, and the difficulties of alternative tests

h) The interval of time an unexpected catastrophic failure, component or otherwise, that may go undetected and leave the system unprotected


Onerous site conditions :-

1. Dusty or dirty environments2. Corrosive chemical atmospheres3. Frequent or continuous vibration4. High humidity5. High or cycling temperatures6. Consistently high levels of energising or auxiliary

quantities

Typically maintain every 12-18 months under ideal conditions and decrease frequency


Visual inspections

The commissioning test stage

At each maintenance test

After heavy fault clearance

More regularly if onerous site conditions

Calibration tests

Trip testing


Recommended maintenance tests

Instruction manuals

Record relay settings

Visual inspection

Secondary injection tests

Contact integrity

Return to ‘in-service’ settings

Check energising quantities


Relays involving static (electronic) components

Electro-static discharge (ESD)

Wrist straps

Modern static relays (K-SERIES, MiCOM etc.)

Fault find to board level only

Protect boards

Corrective Maintenance ofProtective Relays (1)

Cleaning solvents

Trichlortrifluorethane (Ozone damaging)(Arklone, Freon, Flourisol and Supersolve)

PROZONE

Contact lubricants and other lubricants

Contact cleaning burnishers

Contact pressures and settings

Dust removal

Relay recalibration (Why?)

Contents of Section 23 of ‘PRAG’ (1)(Protective Relay Application Guide)

Insulation tests

Current transformer tests

Voltage transformer tests

Test facilities

Secondary injection tests O.C. and E.F.DifferentialPilot wiresNegative phase sequenceDirectional

DistanceD.C. operated


Primary Injection Test (+ on load tests)

O.C. and E.F. relays

Directional

Generator Differential

Transformer Differential

Restricted E.F.

Pilot Wire

Busbar

Negative phase sequence


Tripping and Alarm Annunciation

Periodic Maintenance

In addition to PRAG :-

Consult instruction manuals

Test Terminal Block

To relay coils

To main VTTo maincurrent

transformers

To CT testwindings(if any)

A B C A B C N A B C N

Test Switch and Sockets

To relay coils

To main currenttransformers

To main VT

ABCN

ABCN

Currenttestsockets

Voltagetestsockets

Test selector switchMake before break on CT Circuits

Current TransformerPolarity Check

P2 P1

S1S2 +-

Pushbuttonswitch

Battery

+- A

Current TransformerRatio Check

A B CA2

A1

P1 S1

S2P2

Primary injectiontest set

250V AC supply

Relay or test blockcontact fingers

51

Test pluginsulation

64

51

51

Temporaryshortcircuit

Testing Current TransformerMagnetizing Curve

A B C

P1S1

S2

P2

V

Test plug isolatingcurrent transformersfrom relay coils

Variabletransformer250V 8A

250VA Csupply

Step-up transformerif required

Main circuitbreaker open

To relaycoils

A

Voltage TransformerPhasing Check

ABC

V1

V2

VN

VLV

A B C Phase rotationmeter

A

BC

V1

V2

Overcurrent Test Set

K2

K1

ARangeadjusting CT

Coarsecontrolreactor

Fine controlvariabletransformer

250VA Csupply

Supplyswitch

Backingtransformer10% control

Mediumcontrolreactor

Injectiontransformer

Starttimer

Stoptimer

51

I

Relaycoil

Relay short-circuiting switch

Relay current I = Ammeter reading (A) x K1 K2

Basic Current Control Circuitof CFBA Test-Set

220/250VACSupply50/60Hz

Thermal Overload / OvervoltageProtection

SupplyContractor

Supply ShortingSwitch Timer

Start(Break to Start)

L1 L2

10X

Variac V1

Injection‘Matching’C.T.

O/V

Det

ecto

rC

ircui

t OutputtoRelay

5X 2X 1X

60Hz

50Hz

60Hz

50Hz

T1

0.1A

0.2A

0.5A

1A

2A

5A

10A

A

Sensitivity Check onBiased Differential Relay

Test plugfingers

B BOP

To main currenttransformersOvercurrent

test set250V

A.C. supply OP Relay operating coilB Relay bias coil

Testing Bias Characteristics(Using Overcurrent Test Set)


B BOP

I1+I2

A1

I2

A2

R

Test plugfingers

I1

250V A.C.supply

Overcurrenttest set

Testing Relay Bias Characteristic(Using Resistances)


B BOP

I1+I2

A1

I2

A2

R1 R2

Test plugfingers

I1

250V A.C.supply

A1 and A2 AmmetersOP Relay operating coilB Relay bias coil

Sensitivity Test

Testplug

Feeder isolated

BOP

Pilots

Overcurrenttest set

250VA.C. supply

ABC

Relaycontactfingers

BOP

Testing Sensitivity of NegativePhase Sequence Relay

A

B

C

NOvercurrenttest set

46

Filternetwork

Relaycoil

Test plugin test block

250V A.C.supply

To maincurrenttransformers

Test Equipment forDirectional Relays

V VoltmeterA AmmeterPA Phase angle meter

To other voltage coilsof relay under test(if required)

ABCN

Variabletransformerfor currentcontrol

Choke

440V3 phase4 wire supply

67

67

Relaycurrent coil

Range adjusting CT

PAA

VPA Relayvoltage coil

Variable transformerfor voltage control

440/110Vphase shiftingtransformer

Supply switch

Primary Injection Test Set

250V A.C.supply

A

Variable transformer 40AInjection transformer250/10 + 10 + 10V10kVA

Primary Check onMain Current Transformers

Temporary three-phase short circuit

Primaryinjectiontest set

250VA.C. supply

A

B

C

51

51

51

64A51 Overcurrent relay64 Earth fault relayA Ammeter

Sensitivity Test onEarth Fault Relay

51

51

250VA.C.supply

A

B

C

51

64


Load Test on DirectionalOvercurrent Relays

Load current

A

B

C

Direction of power flowfor relay operation

PAPA

AV

Directional overcurrent relays

A AmmeterV VoltmeterPA Phase angle

meter

A AmmeterV VoltmeterPA Phase angle

meter

A B C

Test Plug Link Connections toReverse Current seen by Relay

To relay

To main VT and CT

20 19 18 17 16 15 14 13 12 11

1 2 3 4 5 6 7 8 9 10

Test plug

Load Test on DirectionalEarth Fault Relay

A AmmeterV VoltmeterPA Phase angle meter

A

PA V

PA

A B C P1 P2

S1 S2

IA

5151

51

V1V2

VL VN

Temporaryshort circuitconnections

Insulating strips inrelay or test blockcontact fingers

Directional earthfault relay

Load current

Testing Sensitivity of Generator Differential Protection Using Primary Injection Test

ABC

87 Generator differential relayV VoltmeterA Ammeter


250V A.C. supply

Generator Isolating links

87V 87

A

87

Testing Sensitivity of Generator Differential Protection Using Generator to Supply Primary Current

87 Generator differential relayV Voltmeter

GeneratorIsolatinglinks

ABC

Temporaryshort circuit

87V 8787

Checking Stability of Generator Differential Protection

ABC

87 Generator differential relayA Ammeter

GeneratorIsolating

linksTemporaryshort circuit

87

A

8787

AA

Shorts across relay/stabilising resistors

Earth Fault Sensitivity Check on Transformer Differential Protection

Temporaryshort circuit

A

250VA.C.supply


Operatingcoils

87 87 87

Bias coils

ABC

Phase Fault Sensitivity Check on Transformer Differential Protection

Temporaryshort circuitA

250VA.C.supply


Operatingcoils

87 87 87

Bias coils

ABC

Stability Check on TransformerDifferential Protection

Temporary short circuitGenerator

87 8787

Bias coilsA

~

Operating coilsInstantaneous current distribution for three-phase short circuit with phase A current at maximum

Sensitivity Check of Restricted Earth Fault Protection

A250V A.C.

supply

Primaryinjectiontest set A

BC

64

V

64 Earth Fault RelayA AmmeterV Voltmeter

Stability Check of Restricted Earth Fault Protection

64 Earth Fault RelayA Ammeter

250V A.C. supply

Primaryinjectiontest set A

BC

64

A Temporary short circuit

A

Sensitivity Check of Negative Phase Sequence Relay

46 Negative phase sequence relayA Ammeter

250VA.C. supply


A B C

A

Filternetwork 46

Temporary short circuit

Test Plug Link Connections forLoad Current Test

To relayfilter network

20 19 18 17 16 15 14 13 12 11

1 2 3 4 5 6 7 8 9 10

A B C N

Earth Fault Sensitivity Check of Pilot Wire Relay

B Relay bias coil OP Relay operating coil A Ammeter

A

B

C

250V A.C. supply


A

B

OPPilots to remoteend relay

Phase Fault Sensitivity Checkof Pilot Wire Relay

B Relay bias coilOP Relay operating coilA Ammeter

A B C


A

OP

Pilots to remoteend relay

B

250V A.C. supply

Load Current Distribution

Instantaneous currentdistribution of three-phasebalanced load withphase A current atmaximum

A B C A B CFeeder

B

OP

BOP

Pilots

Short-Circuiting Connections on Test Plug for Load Test

To relay summation CT

A B C N

20 19 18 17 16 15 14 13 12 11

1 2 3 4 5 6 7 8 9 10

Short circuiting connectionson rear of test plug


A

Ratio Check of Current Transformersof Reference Circuit

A1 and A2 Ammeters87 Busbar Protection relay95 Supervision relay95X Bus wires short-circuiting

relay87 878795

95X

ABCN

A2

Zonebus wires

Test linksPrimary injection

test set

A1

250V A.C.supply

Polarity Check of Reference CircuitCurrent Transformers

A Ammeter87 Busbar Protection

relay95 Supervision relay95X Bus wires short-

circuiting relay

87 878795

95X

ABCN

A

Zonebus wires

Test links


A250V A.C.supply

Temporary short circuitA B C

CT Inter-Group Ratio and Polarity Check in Busbar Protection Scheme

A1 Ammeter for ratio checkA2 Ammeter for polarity

check87 Busbar protection relay95 Supervision relay95X Bus wires short-

circuiting relay

250V

A.C

. sup

ply

Temporary short circuit

Prim

ary

inje

ctio

nte

st s

et

ABCN

A

A1 A1A1 A1

A2A2

A2

Reference circuit Test circuit

Testlinks

Zonebuswires

95X87878795

Sensitivity Check of BusbarProtection Scheme

87 878795

95X

ABCN

Zonebus wires

Test linksPrimary injection

test set

A

250V A.C.supply

V

A B C

Stability Test

Testplug

BOP

Overcurrenttest set

250VA.C. supply

ABC

BOP

Testplug

Pilots

Commissioning

Education

Transcript of Commissioning