uat #1 & #2 protection relay setting & testing

UUUUAAAAT No.1 & No.2 T No.1 & No.2 T No.1 & No.2 T No.1 & No.2 Protection Relay Setting & Protection Relay Setting & Protection Relay Setting & Protection Relay Setting & TestTestTestTestinginginging

Contents

1. Setting of UAT #1 Protection Relay - - - - - - - - - - P. 3 – P13

2. UAT #1 Protection Relay Test Record Sheet - - - - - P.14 – P.21

3. Setting of UAT #2 Protection Relay - - - - - - - - - - - P. 22 – P.32

4. UAT #2 Protection Relay Test Record Sheet - - - - - P. 33 – P.40

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1. Setting of UAT #1 Protection Relay

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Setting of UAT-1 Protection Relay Type RET670F87T - Unit Aux. Transformer Differential Protection

1. Terminal identification

Station Name : KERAMASANBay Name: UAT-1Relay Name RET 670Relay serial NoFrequency 50 HzAux voltage 110 VDC

2. General Data

Transformer: GSUT-1, two windingRated data : Rated power 6 MVA

Voltage ratio 11 kV / 6.3 kVW1 rated current - Ir1 315 AW2 rated current - Ir2 550 AConnection Dyn11 (resistive grounding at Y winding)p.u. Impedance 0.08at Base 6

CT ratio W1 (11kV) 750 / 1 ACT ratio W2 (6.3kV) 1250 / 1 A

VT ratio W1 11 / 0.11 kVVT ratio W2/W3 6.3 / 0.11 kV

Short circuit data :

Three-phase short circuit current at 6.3kV busbar 9300 APhase to Ground short circuit current at 6.3kV busbar 11 APhase current contribution of UAT for 3-Ph fault at 6.3kV busbar 6580 Ameasured at 6.3kV sidePhase current contribution of UAT for 3-Ph fault at 6.3kV busbar 3768.5 Ameasured at 11kV side

3. Setting Considerations

Protection Scheme - Transformer 2 winding differential protection (87T) is applied as main

protection to mostly protect the transformer from internal phase to phase fault.Very small earth fault current due to resistive grounding makes REF protection will not be effective and sensitive enough to protect the transformer frominternal earth fault. Therefore, sensitive earth fault protection relay shall then be provided in the backup protection relay.

Differential current setting (Idmin)

UAT1 F87T 1/4 Keramasan

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The usual practice for transformer protection is to set the bias characteristic to a value of at least twice the value of the expected spill current underthrough faults conditions. Spill current may arise from several conditions such as : - transformer phase shift and ratio error - current transformer ratio error - different CTs characteristicIdmin of 0.3 x Ibase is normally recommended to be applied.

Zero-sequence current substraction A differential protection may operate unwanted due to external earth faults in cases where the zero sequence current can flow only on one side of the power transformer

but not on the other side. This is the situation when the zero sequence currentcan not be properly transformed to the other side of the power transformerhaving a combined Y and D connection group. In such case, the zero sequencesubstraction function shall be set ON for Y winding and OFF for D winding.

4. Setting of analogue inputConfigure analogue inputs for TRM1 (-X401) :Set analogue current channels

AI1 AI2 AI3 AI4 AI5Ctprim = 750 750 750 1250 1250Ctsec = 1 A 1 A 1 A 1 A 1 ACTStarPoint = To Object To Object To Object To Object To Object

AI6 AI7 AI8 AI9Ctprim = 1250 not used not used not usedCtsec = 1 A not used not used not usedCTStarPoint = To Object not used not used not used

Set analogue voltage channelsAI10 AI11 AI12

Vtprim = not used not used not usedVtsec = not used not used not used

5. Protection Settings

5.1. Setting of the Differential function data under T2WPDIF General settings.

Winding 1 (W1) Winding 2 (W2)RatedVoltageW1 11 kV RatedVoltageW2 6.3 kVRatedCurrentW1 315 A RatedCurrentW2 550 AConnectTypeW1 D ConnectTypeW2 YTconfigForW1 No TconfigForW2 NoCT1ratingW1 750 A CT1ratingW2 1250 AZSCurrSubtrW1 Off ZSCurrSubtrW2 On

ClockNumberW2 11


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Note : All other setting parameters under general setting are not relevant. Use default values.

5.2. Differential Protection Setting (87T) under T2WPDIF Setting group:

Operation = OnOperation of SOTF feature

SOTFMode = OffSetting of differential current alarm

IDiffAlarm = 0.2 *IbaseSetting of time delay of differential current alarm

tAlarmDelay = 10 sSetting of minimum differential operating current

IdMin = 0.3 *IbaseSetting of cross-over point between slope 1 and slope 2

EndSection1 = 1.25 IbaseSetting of slope 2 stabilisation, Slope 1 has fixed stabilization

SlopeSection2 = 40% *IbiasSetting of cross-over point between slope 2 and slope 3

EndSection2 = 3.00 IbaseSetting of slope 2 stabilisation

SlopeSection3 = 80% *IbiasSetting of minimum differential operating current for unrestraint step

Idunre = 20.00 *IbaseSet the operation of Cross Blocking logic On-Off

OpCrossBlock = OnSet the second and fifth harmonic stabilizing level when transformers are inside the zone

I2/I1Ratio = 15%I5/I1Ratio = 25%

Set the operation of Negative sequence differential protectionNegSeqDiffEn = No

Setting of minimum negative sequence differential current levelIMinNegSeq = 0.04

Setting of the Relay operating anglesNegSeqROA = 60 deg

Set the operation of Open CT detectionOpenCTEnable = No

Note : All other setting parameters under this setting group are not relevant.

5.3. All other protection functions

Operation = Off

6. Assignment of Binary Input BIM_3


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BIM_3.BI01 : Bucholz Trip

BIM_3.BI02 : Rapid Pressure Relay TripBIM_3.BI03 : Oil Level Low Low TripBIM_3.BI04 : Protective Relay TripBIM_3.BI05 : Oil Temperature TripBIM_3.BI06 : HV Winding Temperature TripBIM_3.BI07 : Not usedBIM_3.BI08 : Trip from Generator Protection (59BG)BIM_3.BI09 : Trip from Generator Protection (52G Mech Fail)BIM_3.BI10 : Trip from GSUT ProtectionBIM_3.BI11 : Reset Lockout

BIM_3.BI12 : Not usedBIM_3.BI13 : Not usedBIM_3.BI14 : Not usedBIM_3.BI15 : Not usedBIM_3.BI16 : Not used

7. Assignment of Binary Output BOM_4

BOM_4.BO01 : Transformer Differential Trip (T2WPDIF)

BOM_4.BO02 : Not usedBOM_4.BO03 : Trip from Generator Protection

BOM_4.BO04 : Trip from UAT Transformer's Protection (Bucholz etc)

BOM_4.BO05 : Not usedBOM_4.BO06 : Not usedBOM_4.BO07 : Not usedBOM_4.BO08 : Not usedBOM_4.BO09 : Transformer Differential Trip (T2WPDIF)

BOM_4.BO10 : Not usedBOM_4.BO11 : Trip from Generator ProtectionBOM_4.BO12 : Not usedBOM_4.BO13 : Trip from UAT Transformer's Protection (Bucholz etc)

BOM_4.BO14 : Trip from GSUT ProtectionBOM_4.BO15 : Transformer Differential Trip (T2WPDIF)

BOM_4.BO16 : Not usedBOM_4.BO17 : Trip from GSUT ProtectionBOM_4.BO18 : Trip from Generator Protection

BOM_4.BO19 : Not usedBOM_4.BO20 : Not usedBOM_4.BO21 : Not usedBOM_4.BO22 : Not usedBOM_4.BO23 : Not usedBOM_4.BO24 : Not used


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Setting of UAT-1 Protection Relay Type REF615F5051 - Backup OC & EF Protection


Station Name KERAMASANBay Name: UAT-1Relay Name REF615Relay serial NoFrequency 50 HzAux voltage 110 VDC

2. General Data

Transformer: UAT-1, two windingRated data : Rated power 6 MVA



Short circuit data :Three-phase short circuit current at 6.3kV busbar 9300 APhase to Ground short circuit current at 6.3kV busbar 11 APhase current contribution of UAT for 3-Ph fault at 6.3kV busbar 6580 Ameasured at 6.3kV sidePhase current contribution of UAT for 3-Ph fault at 6.3kV busbar 3768.5 Ameasured at 11kV side

Maximum tripping time for 6.3kV outgoing feeders Instantaneous


Protection Scheme - Low-set phase overcurrent (51) protection at 11kV side are used as backup

protection for differential (87T) and REF (87REF) protection.To maintain selectivity against downstream protection relays, a time delay of 0.5s on top of the downstream (6.3kV outgoing feeders) protection relays maximum operating time shall be introduced.

- Instantaneous-set overcurrent (50) at 11kV side is applied to protect the transformer during short circuit condition. Time delay shall be introduced to maintain selectivityfrom the fault which occur at the other parts of the system.

UAT1 F5051 1 of 6 Keramasan

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- Sensitive earth fault/SEF (50S) of this relay will be applied at 6.3kV to detectearth fault condition at 6.3kV system. To maintain selectivity against earth faultprotection relay at 6.3kV outgoing feeders, a time delay of 0.5s on top of the outgoing feeders tripping time is introduced. As the fault current is considerably small,a longer operating time is somehow still acceptable as long as not exceeding therated time of NGR (10s).

- To avoid unwanted operation of the overcurrent and earth fault protection due toinrush current during transformer startup, the inrush detection element INRPHARis activated to give a blocking signal to the overcurrent & earth fault element wheninrush current is detected.

4. Setting of analogue inputAnalog input settings, phase currents

Secondary current = 1 APrimary current = 750 A

Amplitude corr. A = 1Amplitude corr. B = 1Amplitude corr. C = 1

Nominal current = 315 A {In}Rated secondary value = 3 mV/Hz

Reverse polarity = 0 {False}

Analog input settings, residual currents

Secondary current = 1 APrimary current = 1250 AAmplitude corr. = 1


5. General System SettingRated frequency = 50 Hz

Phase rotation = ABCBlocking mode = Freeze timer

Bay Name = UAT2IDMT saturation point = 50

6. Setting of Three Phase Overcurrent Function (PHxPTOC) on 11 kV side

6.1. PHIPTOC (Instantaneous) Non group settings:

Activation of the PHIPTOC functionOperation = 1 { 1=On }

Number of phases required for operate activationNum of start phase = 1 { 1=1-out-of-3 }

Reset delay timeReset delay time = 20 ms { instantaneous }


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6.2. PHIPTOC (Instantaneous) Group settings:

Start values is set at 130% of transformer short circuit current to get selectivity with faults at 6.3kV.Start Value PHHPTOC = 130% x 3768.5 A

= 4899.1 AStart Value PHHPTOC = 15.6 x In

Operate delay timeOperate delay time = 20 ms { instantaneous }

Note : All other setting parameters are not relevant. Default values can be used.

6.3. PHHPTOC (high-set) Non group settings:

Activation of the PHHPTOC functionOperation = 5 { 5=Off }


6.4. Setting of parameters for PHLPTOC (low-set) Non-group Setting

Activation of the PHLPTOC functionOperation = 1 { 1=On }

Number of phases required for activationNum of start phase = 1 out of 3

Minimum operate time for IDMT curveMin. oper. Time = 40 ms

Reset delay timeReset delay time = 20 ms

Curve parameter for programmable curveCurve parameter A, B, C, D, E = default {NA}

6.5. PHLPTOC (low-set) Group settings:Start values is set at 110% of transformer rated current.

Start Value PHLPTOC = 120% x 315 A= 378 A

Start Value PHLPTOC = 1.2 x InMultiplier for scalng the start value

Start value Mult = 1Time multiplier setting (TMS)

Time multiplier = 1 {See note below}Operate delay time

Time delay PHLPTOC = 400 ms {Not relevant for inverse type}Operating curve type

Curve PHLPTOC = IEC Extremely InverseSelection of reset curve type

Type of reset curve = 1 {Immediate}

Note : Time delayed PHLPTOC shall be set to operate in about 0.8 s at short circuit


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current to give safe margin to the transformer main protection and other unit protection at the other part of the system.Short circuit current = 3768.5 A

= 12 x Inwith start value = 1.2 x Inand set time multiplier = 1for extremely inverse curve, the operating time t is :

t = 0.814 s --> OK

7. Setting of Earth Fault Protection Function (EFxPTOC) on 6.3 kV side

7.1. EFIPTOC (Instantaneous) Non group settings:

Activation of the EFIPTOC functionOperation = 5 { 5=Off }


7.2. EFHPTOC (high-set) Non group settings:

Activation of the EFHPTOC functionOperation = 5 { 5=Off }


7.3. EFLPTOC (low-set) Non group settings:

Activation of the EFLPTOC functionOperation = 1 { 1=On }




Selection for used Io signalIo signal Sel = 1 {Measured Io)

7.3. EFLPTOC (low-set) Group settings:Start value for earth fault is set at 50% of maximum earth fault current.

Start Value EFLPTOC = 50% x 11 A {See note below}= 6 A

Start Value EFLPTOC = 0.02 x InMultiplier for scalng the start value


Time multiplier = 0.1 {See note below}Operate delay time


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Time delay EFLPTOC = 0.9 sOperating curve type

Curve EFLPTOC = Definite timeSelection of reset curve type


8. Setting of Inrush Detector INRPHAR

8.1. Inrush Detector INRPHAR Group SettingRatio of the 2nd to the 1st harmonic leading to restraint

Start value = 0.15 %Operate delay time

Operate delay time = 20 ms

8.2. Inrush Detector INRPHAR Non Group Setting

Activation of the INRPHAR functionOperation = 1 { 1=On }


9. All other protection functions

Operation = 5 { 5=Off }

10. Assignment of Binary Input

Binary Input Terminal -X110_

BI1 : Not usedBI2 : Not usedBI3 : Not usedBI4 : Not usedBI5 : Not usedBI6 : Not usedBI7 : Not usedBI8 : Not usedBI9 : Not usedBI10 : Not used


BI1

BI2

BI3

BI4 : Reset lockout

11. Assignment of Binary Output


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Binary Output Terminal -X100_

PO1 : Overcurrent Trip

(Operation of PHHPTOC, PHLPTOC)

PO2 : SEF Trip

(Operation of EFLPTOC)

SO1 : Overcurrent Trip

SO2 : SEF Trip

PO3

PO4



SO2 : SEF Trip

SO3

SO4


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2. UAT #1 Protection Relay Test Record Sheet

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Equipment :

Feeder :

1. Reference Drawing

Schematic Diagram :

Transformer Bay :

2. General Data

Manufacture : Designation :

Type : Sereal No. :

3. Commissioning Tests

3.1 Visual Check

a) Physically Good ? :

b) Relay Healthy ? :

c) Mounting and wiring completed ? :

Protection Relay Test

Unit Aux. Transformer Differential Protection Relay RET670

UAT #1

KPP-00-TPS-W-141

11kV 6.3kV UAT #1

ABB

RET670

F87T


3.2 Verifying the connections and the analog inputs

Apply input signals as needed and verify that signals are measured correctly

1

2

3

4

5

6

7

No. ProcedureInjected Values

Secondary

Measured

Values PrimaryRemarks

Inject current phase R → A101 A A


Inject current phase S → A105 A A


Inject current phase T → A103 A A


Inject current Neutral → A107 A A

Contractor

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3.3 Deferential Protection Test

(1) Check on HV side Secondary Injection

No. Procedure Items to be verified. Remarks

1 Make sure that REF and OC / EF

function are set to off.

2 Connect the test set for injection of 3

phase current to the current terminals

of RET670 which are connected to the

CT's on HV side of transformer

3 Increase the current in phase L1 until

the protection operates and check

L1

a) the operating current (Iop) a) Iop : A

b) Trip contacts operation b) Trip contact :

Operate / Not operate

c) Alarm contact operation c) Alarm contact :

a) Iop : A





L2 For stable condition,

Trip not operated

a) the operating current (Iop)


For stable condition,

Trip not operated











L3

Contractor

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(2) Check on LV side Secondary Injection







CT's on LV side of transformer



L2




L1








4 Increase the current in phase L3 until L3





L3




Contractor

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3.4 6.3kV Restricted EF Protection Test

(1) Secondary Injection

No.

4. Remarks :

Procedure Items to be verified. Remarks

1 Make sure that Differential protection

and OC/EF function are set to off.

2 Connect the test set for injection of

neutral current to the current terminals

of RET670 to which the NCT 20kV is

connected

3 Increase the current in until the

protection operates and check

L1






Contractor

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Equipment :

Feeder :


Schematic Diagram :

Transformer Bay :

2. General Data


Type : Sereal No. :


3.1 Visual Check





Backup OC & EF Protection Relay REF615

UAT #1

KPP-00-TPS-W-141

11kV 6.3kV UAT

ABB

RET615

F5051

1VHR91059397




1

2

3

4


Secondary

Measured


Inject current phase T A A

Inject current phase N A A

Inject current phase R A A

Inject current phase S A A

Contractor

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3.3 Testing of the phase overcurrent protection

The test is performed as a secondary test, by injecting current to the current energizing

inputs with the setting values used during normal operation

No.

2 Inject the current (Ii) in phase L2



Ii = 2.5 * I > * rated current input Start of stage I > :

.I > setting : * In


.I > setting : * In Trip of stage I > :

.t > setting :

s

Operation time :

s

Trip of stage I > :

.t > setting :

s

Operation time :

s




.t > setting :

s

Operation time :

s4 Inject the current (Ii) in phase L1

Ii = 8 * I >>> * rated current input Start of stage I >>> :

.I >>> setting : * In Trip of stage I >>> :

.t >>> setting :

s

Operation time :




.t >>> setting :

s

Operation time :





.t >>> setting :

s

Operation time :

s

Contractor

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3.4 Testing of the earth fault protection



No.

4. Remarks :

Start of stage I > :

.I0 > setting : * In Trip of stage I > :

.

2 Inject the current (Ii) in the earth fault

Procedure Items to be verified.

energizing input :

Ii = 2.5 * I0 >> * rated current input Start of stage I >> :

.I0 >> setting : * In Trip of stage I >> :

.t0 >> setting : s Operation time :

s

Remarks


energizing input :

Ii = 2.5 * I0 > * rated current input

t0 > setting : s Operation time :

s

Contractor

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3. Setting of UAT #2 Protection Relay

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Setting of UAT-2 Protection Relay Type RET670F87T - Unit Aux. Transformer Differential Protection


Station Name : KERAMASANBay Name: UAT-2Relay Name RET 670Relay serial NoFrequency 50 HzAux voltage 110 VDC

2. General Data

Transformer: GSUT-2, two windingRated data : Rated power 6 MVA



VT ratio W1 11 / 0.11 kVVT ratio W2/W3 6.3 / 0.11 kV

Short circuit data :

Three-phase short circuit current at 6.3kV busbar 9300 APhase to Ground short circuit current at 6.3kV busbar 11 APhase current contribution of UAT for 3-Ph fault at 6.3kV busbar 6580 Ameasured at 6.3kV sidePhase current contribution of UAT for 3-Ph fault at 6.3kV busbar 3768.5 Ameasured at 11kV side


Protection Scheme - Transformer 2 winding differential protection (87T) is applied as main

protection to mostly protect the transformer from internal phase to phase fault.Very small earth fault current due to resistive grounding makes REF protection will not be effective and sensitive enough to protect the transformer frominternal earth fault. Therefore, sensitive earth fault protection relay shall then be provided in the backup protection relay.

Differential current setting (Idmin)


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The usual practice for transformer protection is to set the bias characteristic to a value of at least twice the value of the expected spill current underthrough faults conditions. Spill current may arise from several conditions such as : - transformer phase shift and ratio error - current transformer ratio error - different CTs characteristicIdmin of 0.3 x Ibase is normally recommended to be applied.

Zero-sequence current substraction A differential protection may operate unwanted due to external earth faults in cases where the zero sequence current can flow only on one side of the power transformer

but not on the other side. This is the situation when the zero sequence currentcan not be properly transformed to the other side of the power transformerhaving a combined Y and D connection group. In such case, the zero sequencesubstraction function shall be set ON for Y winding and OFF for D winding.

4. Setting of analogue inputConfigure analogue inputs for TRM1 (-X401) :Set analogue current channels

AI1 AI2 AI3 AI4 AI5Ctprim = 750 750 750 1250 1250Ctsec = 1 A 1 A 1 A 1 A 1 ACTStarPoint = To Object To Object To Object To Object To Object

AI6 AI7 AI8 AI9Ctprim = 1250 not used not used not usedCtsec = 1 A not used not used not usedCTStarPoint = To Object not used not used not used

Set analogue voltage channelsAI10 AI11 AI12

Vtprim = not used not used not usedVtsec = not used not used not used

5. Protection Settings

5.1. Setting of the Differential function data under T2WPDIF General settings.

Winding 1 (W1) Winding 2 (W2)RatedVoltageW1 11 kV RatedVoltageW2 6.3 kVRatedCurrentW1 315 A RatedCurrentW2 550 AConnectTypeW1 D ConnectTypeW2 YTconfigForW1 No TconfigForW2 NoCT1ratingW1 750 A CT1ratingW2 1250 AZSCurrSubtrW1 Off ZSCurrSubtrW2 On

ClockNumberW2 11


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Note : All other setting parameters under general setting are not relevant. Use default values.

5.2. Differential Protection Setting (87T) under T2WPDIF Setting group:

Operation = OnOperation of SOTF feature

SOTFMode = OffSetting of differential current alarm

IDiffAlarm = 0.2 *IbaseSetting of time delay of differential current alarm

tAlarmDelay = 10 sSetting of minimum differential operating current

IdMin = 0.3 *IbaseSetting of cross-over point between slope 1 and slope 2

EndSection1 = 1.25 IbaseSetting of slope 2 stabilisation, Slope 1 has fixed stabilization

SlopeSection2 = 40% *IbiasSetting of cross-over point between slope 2 and slope 3

EndSection2 = 3.00 IbaseSetting of slope 2 stabilisation

SlopeSection3 = 80% *IbiasSetting of minimum differential operating current for unrestraint step

Idunre = 20.00 *IbaseSet the operation of Cross Blocking logic On-Off

OpCrossBlock = OnSet the second and fifth harmonic stabilizing level when transformers are inside the zone

I2/I1Ratio = 15%I5/I1Ratio = 25%

Set the operation of Negative sequence differential protectionNegSeqDiffEn = No

Setting of minimum negative sequence differential current levelIMinNegSeq = 0.04

Setting of the Relay operating anglesNegSeqROA = 60 deg

Set the operation of Open CT detectionOpenCTEnable = No

Note : All other setting parameters under this setting group are not relevant.

5.3. All other protection functions

Operation = Off

6. Assignment of Binary Input BIM_3


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BIM_3.BI01 : Bucholz Trip

BIM_3.BI02 : Rapid Pressure Relay TripBIM_3.BI03 : Oil Level Low Low TripBIM_3.BI04 : Protective Relay TripBIM_3.BI05 : Oil Temperature TripBIM_3.BI06 : HV Winding Temperature TripBIM_3.BI07 : Not usedBIM_3.BI08 : Trip from Generator Protection (59BG)BIM_3.BI09 : Trip from Generator Protection (52G Mech Fail)BIM_3.BI10 : Trip from GSUT ProtectionBIM_3.BI11 : Reset Lockout

BIM_3.BI12 : Not usedBIM_3.BI13 : Not usedBIM_3.BI14 : Not usedBIM_3.BI15 : Not usedBIM_3.BI16 : Not used

7. Assignment of Binary Output BOM_4

BOM_4.BO01 : Transformer Differential Trip (T2WPDIF)

BOM_4.BO02 : Not usedBOM_4.BO03 : Trip from Generator Protection

BOM_4.BO04 : Trip from UAT Transformer's Protection (Bucholz etc)

BOM_4.BO05 : Not usedBOM_4.BO06 : Not usedBOM_4.BO07 : Not usedBOM_4.BO08 : Not usedBOM_4.BO09 : Transformer Differential Trip (T2WPDIF)

BOM_4.BO10 : Not usedBOM_4.BO11 : Trip from Generator ProtectionBOM_4.BO12 : Not usedBOM_4.BO13 : Trip from UAT Transformer's Protection (Bucholz etc)

BOM_4.BO14 : Trip from GSUT ProtectionBOM_4.BO15 : Transformer Differential Trip (T2WPDIF)

BOM_4.BO16 : Not usedBOM_4.BO17 : Trip from GSUT ProtectionBOM_4.BO18 : Trip from Generator Protection

BOM_4.BO19 : Not usedBOM_4.BO20 : Not usedBOM_4.BO21 : Not usedBOM_4.BO22 : Not usedBOM_4.BO23 : Not usedBOM_4.BO24 : Not used


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Setting of UAT-2 Protection Relay Type REF615F5051 - Backup OC & EF Protection


Station Name KERAMASANBay Name: UAT-2Relay Name REF615Relay serial NoFrequency 50 HzAux voltage 110 VDC

2. General Data

Transformer: UAT-2, two windingRated data : Rated power 6 MVA



Short circuit data :Three-phase short circuit current at 6.3kV busbar 9300 APhase to Ground short circuit current at 6.3kV busbar 11 APhase current contribution of UAT for 3-Ph fault at 6.3kV busbar 6580 Ameasured at 6.3kV sidePhase current contribution of UAT for 3-Ph fault at 6.3kV busbar 3768.5 Ameasured at 11kV side

Maximum tripping time for 6.3kV outgoing feeders Instataneous


Protection Scheme - Low-set phase overcurrent (51) protection at 11kV side are used as backup

protection for differential (87T) and REF (87REF) protection.To maintain selectivity against downstream protection relays, a time delay of 0.5s on top of the downstream (6.3kV outgoing feeders) protection relays maximum operating time shall be introduced.

- High-set overcurrent (50) at 11kV side is applied to protect the transformer during short circuit condition. Time delay shall be introduced to maintain selectivityfrom the fault which occur at the other parts of the system.


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- Sensitive earth fault/SEF (50S) of this relay will be applied at 6.3kV to detectearth fault condition at 6.3kV system. To maintain selectivity against earth faultprotection relay at 6.3kV outgoing feeders, a time delay of 0.5s on top of the outgoing feeders tripping time is introduced. As the fault current is considerably small,a longer operating time is somehow still acceptable as long as not exceeding therated time of NGR (10s).

- To avoid unwanted operation of the overcurrent and earth fault protection due toinrush current during transformer startup, the inrush detection element INRPHARis activated to give a blocking signal to the overcurrent & earth fault element wheninrush current is detected.

4. Setting of analogue inputAnalog input settings, phase currents

Secondary current = 1 APrimary current = 750 A

Amplitude corr. A = 1Amplitude corr. B = 1Amplitude corr. C = 1

Nominal current = 315 A {In}Rated secondary value = 3 mV/Hz


Analog input settings, residual currents

Secondary current = 1 APrimary current = 1250 AAmplitude corr. = 1


5. General System SettingRated frequency = 50 Hz

Phase rotation = ABCBlocking mode = Freeze timer

Bay Name = UAT2IDMT saturation point = 50

6. Setting of Three Phase Overcurrent Function (PHxPTOC) on 11 kV side

6.1. PHIPTOC (Instantaneous) Non group settings:

Activation of the PHIPTOC functionOperation = 1 { 1=On }

Number of phases required for operate activationNum of start phase = 1 { 1=1-out-of-3 }

Reset delay timeReset delay time = 20 ms { instantaneous }


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6.2. PHIPTOC (Instantaneous) Group settings:

Start values is set at 130% of transformer short circuit current to get selectivity with faults at 6.3kV.Start Value PHHPTOC = 130% x 3768.5 A

= 4899.1 AStart Value PHHPTOC = 15.6 x In

Operate delay timeOperate delay time = 20 ms { instantaneous }


6.3. PHHPTOC (high-set) Non group settings:

Activation of the PHHPTOC functionOperation = 5 { 5=Off }

6.4. Setting of parameters for PHLPTOC (low-set) Non-group Setting

Activation of the PHLPTOC functionOperation = 1 { 1=On }

Number of phases required for activationNum of start phase = 1 out of 3




6.5. PHLPTOC (low-set) Group settings:Start values is set at 110% of transformer rated current.

Start Value PHLPTOC = 120% x 315 A= 378 A

Start Value PHLPTOC = 1.2 x InMultiplier for scalng the start value


Time multiplier = 1 {See note below}Operate delay time

Time delay PHLPTOC = 400 ms {Not relevant for inverse type}Operating curve type

Curve PHLPTOC = IEC Extremely InverseSelection of reset curve type


Note : Time delayed PHLPTOC shall be set to operate in about 0.8 s at short circuit current to give safe margin to the transformer main protection and other


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unit protection at the other part of the system.Short circuit current = 3768.5 A

= 12 x Inwith start value = 1.2 x Inand set time multiplier = 1for extremely inverse curve, the operating time t is :

t = 0.814 s --> OK

7. Setting of Earth Fault Protection Function (EFxPTOC) on 6.3 kV side

7.1. EFIPTOC (Instantaneous) Non group settings:

Activation of the EFIPTOC functionOperation = 5 { 5=Off }


7.2. EFHPTOC (high-set) Non group settings:

Activation of the EFHPTOC functionOperation = 5 { 5=Off }


7.3. EFLPTOC (low-set) Non group settings:

Activation of the EFLPTOC functionOperation = 1 { 1=On }




Selection for used Io signalIo signal Sel = 1 {Measured Io)

7.3. EFLPTOC (low-set) Group settings:Start value for earth fault is set at 50% of maximum earth fault current.

Start Value EFLPTOC = 50% x 11 A {See note below}= 6 A

Start Value EFLPTOC = 0.02 x InMultiplier for scalng the start value


Time multiplier = 0.1 {See note below}Operate delay time

Time delay EFLPTOC = 0.9 s


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Operating curve typeCurve EFHPTOC = Definite time

Selection of reset curve typeType of reset curve = 1 {Immediate}

8. Setting of Inrush Detector INRPHAR

8.1. Inrush Detector INRPHAR Group SettingRatio of the 2nd to the 1st harmonic leading to restraint

Start value = 0.15 %Operate delay time

Operate delay time = 20 ms

8.2. Inrush Detector INRPHAR Non Group Setting

Activation of the INRPHAR functionOperation = 1 { 1=On }


9. All other protection functions

Operation = 5 { 5=Off }

10. Assignment of Binary Input


BI1 : Not usedBI2 : Not usedBI3 : Not usedBI4 : Not usedBI5 : Not usedBI6 : Not usedBI7 : Not usedBI8 : Not usedBI9 : Not usedBI10 : Not used


BI1

BI2

BI3

BI4 : Reset lockout

11. Assignment of Binary Output


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PO1 : Overcurrent Trip

(Operation of PHHPTOC, PHLPTOC)

PO2 : SEF Trip

(Operation of EFLPTOC)


SO2 : SEF Trip

PO3

PO4



SO2 : SEF Trip

SO3

SO4


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4. UAT #2 Protection Relay Test Record Sheet

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Equipment :

Feeder :


Schematic Diagram :

Transformer Bay :

2. General Data


Type : Sereal No. :


3.1 Visual Check




RET670


Unit Aux. Transformer Differential Protection Relay RET670

UAT #2

KPP-00-TPS-W-141

11kV 6.3kV UAT #2

ABB F87T




1

2

3

4

5

6

7


Secondary

Measured






Inject current Neutral → A107 A A



Contractor

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3.3 Deferential Protection Test

(1) Check on HV side Secondary Injection





1 Make sure that REF and OC / EF

function are set to off.




CT's on HV side of transformer





L2



L1


Trip not operated






Trip not operated










L3

Contractor

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(2) Check on LV side Secondary Injection

No. Procedure Items to be verified.

a) Iop : A




Remarks




CT's on LV side of transformer



L1

a) the operating current (Iop)




L2






4 Increase the current in phase L3 until L3








L3

Contractor

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3.4 6.3kV Restricted EF Protection Test

(1) Secondary Injection

No.

4. Remarks :


1 Make sure that Differential protection

and OC/EF function are set to off.

2 Connect the test set for injection of

neutral current to the current terminals

of RET670 to which the NCT 20kV is

connected

3 Increase the current in until the

protection operates and check

L1






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Equipment :

Feeder :


Schematic Diagram :

Transformer Bay :

2. General Data


Type : Sereal No. :


3.1 Visual Check




UAT #2

KPP-00-TPS-W-141

11kV 6.3kV UAT

ABB F5051

RET615


Backup OC & EF Protection Relay REF615




1

2

3

4


Secondary

Measured


Inject current phase R A A

Inject current phase N A A

Inject current phase S A A

Inject current phase T A A

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3.3 Testing of the phase overcurrent protection







.t > setting :

s

Operation time :




.t > setting :

s

Operation time :




.t > setting :

s

Operation time :




.t >>> setting :

s

Operation time :

s5 Inject the current (Ii) in phase L25 Inject the current (Ii) in phase L2



.t >>> setting :

s

Operation time :




.t >>> setting :

s

Operation time :

s

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3.4 Testing of the earth fault protection



No.

4. Remarks :

Remarks


energizing input :

Ii = 2.5 * I0 > * rated current input Start of stage I > :

.I0 > setting : * In Trip of stage I > :

.t0 > setting : s Operation time :

s2 Inject the current (Ii) in the earth fault

Procedure Items to be verified.

energizing input :

Ii = 2.5 * I0 >> * rated current input Start of stage I >> :

.I0 >> setting : * In Trip of stage I >> :

.t0 >> setting : s Operation time :

s

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uat #1 & #2 protection relay setting & testing

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