Relay Setting Chart _ CRP Panel_Shambhu_REVB

GRASIM CEMENTS - GRINDING UNIT AT PANIPAT

RECOMMENDED RELAY SETTING CHART

33/6.6 kV, 12/16 MVA TRANSFORMER BAY

Prepared by : ABB Date : 02.01.2007

Revision-A

RECOMMENDED RELAY SETTING CH

SI. No.

Type of Protection

Relay Make PROTECTION ANSI / No. CODE

1

Differential Protection (Restrained)

ABB - RET 670

Stage 1

2

3

(T2D1 )

Differential ABB - RET Protection (Unrestrained) 670 ,Stage 2

Restricted Earth fault Protection ( Low impedance

87T>

ABB - RET 670

87T>>

64R LV

64R HV Restricted Earth fault Protection (High Impedence

ABB - RET 670

64R LV

64R HV

4

Stand -by Earth fault Protection (HV Side)

ABB - RET 670

51s-EFR HV ( 4th-Stage- OFF)

RET-670 , TIME CO-ORDINATED SETTINGS OF Stan-byEFR ( HV & LV )

Stand -by Earth fault Protection (LV Side)

ABB - RET 670

600/1A (132KV side)

51s-EFR LV I_base STAGE-1

I1> t1>

STAGE-2

STAGE-3

I2> t2> I3> t3>

STAGE-4

I4> t4>

Stand -by Earth fault Protection (HV Side)

ABB - RET 670

150/1A (132KV side)

51s-EFR HV I_base STAGE-1

STAGE-2

STAGE-3

I1> t1> I2> t2> I3> t3>

STAGE-4

I4> t4>

MMENDED RELAY SETTING CHART FOR 132/11.5kV, 20/25 MVA TRANSFORMER Relay Setting CT Ratio / PT Ratio/ OTHER

Available setting range Parameter

Description

150/1A (132KV side)

Operation

on

2000/1A (11 kV Side)

IdMin

Setting of minimum differential operating current

%Z = 12.5% ( TAKE FROM Name plate of trafo. )

End section 1

Cross-Over point b/w slope1 & Slope-2

Vector group = YNyn0

Slope section 2 End section 2 Slope section 3

Setting of slope 2 stabilisation, (Slope 1 has fixed stabilization) Cross-Over point b/w slope2 & Slope-3 Setting of slope 3 stabilisation,

150/1A (132KV side) 2000/1A (11 kV Side)

Idunre

Differential current, High set (Unrestrained)

Cross blocking logic

OpCrossBlock

= on

Id2f / Id1f > (%)

2nd Harmonic restraint

Id5f / Id1f> (%)

5th Harmonic restraint

OpNegSeqDiff =

= on

IMinNegSeq =

Setting of minimum negative sequence differential current level

NegSeqROA

Relay operate angle

Set the operation of Negative sequence differential protection

2000/1A (11 kV Side)

Idmin (%) ROA

Relay operate angle

150/1A (132KV side)

2000/1A (11 kV Side)

150/1A (132KV side)

150/1A (132KV side)

Idmin (%) ROA

Relay operate angle

U alarm

Operate voltage

t Alarm

Operate time

U trip

Operate voltage

t trip

Operate time

Rs U alarm

Series Resistor Operate voltage

t Alarm

Operate time

U trip

Operate voltage

t trip

Operate time

Rs

Series Resistor

IN1>/ Ib

Base Current Setting Dir mode

Ibase 1st-stage

t11>

DT setting

NA

k11>

TMS

IN2>/ Ib

Base Current Setting Dir mode

2nd-stage

t1 2>

DT setting

NA

k1 2>

TMS

IN3>/ Ib

Base Current Setting Dir mode

3rd-stage

t1 3>

DT setting

NA

k1 3>

TMS

NEW SETTINGS

OLD SETTINGS.

Remarks

600/1A (132KV side) 100%

80%

80% of Ibase

80% of Ibase

0.96 sec

0.0 sec

50% of Ibase

50% of Ibase

1.2 sec

0.40 sec

40% of Ibase

40% of Ibase

1.4sec

0.80 sec

30% of Ibase

30% of Ibase

1.6sec

1.20 sec

t= 0.96 sec. is the NormalEFR ( in incomer of 11KVrex-521 ) Relay's time setting. So, the same has been maintained as triptime to SB-EFR-LV.

150/1A (132KV side) 100%

80%

80% of Ibase

80% of Ibase

1.26 sec 100% of Ibase

0.3 sec 100% of Ibase

1.46 sec

0.15 sec

off

off

OFF

OFF

off

off

OFF

OFF

Assuming a time descripation of 0.3 sec. b/w 11KV & 132KV -trip time , t1= 0.96 + 0.3sec. = 1.26 SEC.

0/25 MVA TRANSFORMER Relay Setting

ange

Remarks

Recommended setting Available range

PSM

TMS/DMT

----

----

----

0.10-0.60

0.25 * Ibase.

Inst

0.2 - 1.5

1.25 * Ibase.

10.0 -50.0 %

40 * Ibias

1.0 -10

3 * Ibase.

30.0 -100.0 %

80 * Ibias

100- 5000 % of Ibase

10 * Ibase.

-----

-----

5-100 % of fn

15%

5-100 % of fn

25%

-----

-----

(0.01 - 0.10 )* Iopr.

0.04 * Iopr.

60 - 90 Degrees

60 °

4.0 -100.0

30%

(sec)

see ANNEXURE-01

60 - 90 Degrees

60 °

Inst

Inst This settings may not be applicable - while we have adopted High -Impedence based REFR-Protection.

4.0 -100.0

30%

Inst

60 - 90 Degrees

60 °

( 2 -500 ) V

N/A

0 - 60 sec

N/A

( 5 -900 ) V

109.5 V

-----

----

10 -20000 Ohms. ( 2 -500 ) V

396 ohms. N/A

0 - 60 sec

N/A

( 5 -900 ) V

63 V

-----

----

10 -20000 Ohms.

250 ohms.

1.0 -2500.0 % Ibase

20% * Ibase

-----

Non directional

0 - 60 Secs

----

1.0 sec.

0.05 - 999

0.15 Secs

NI 0.15 Secs

1.0 -2500.0 % Ibase

15% * Ibase

-----

Non directional

0 - 60 Secs

----

1.5 sec.

0.05 - 999

0.15 Secs

NI 0.15 Secs

1.0 -2500.0 % Ibase

10% * Ibase

-----

Non directional

0 - 60 Secs

----

2.0 sec.

0.05 - 999

0.15 Secs

NI 0.15 Secs

5.0 sec.

This settings may not be applicable - while we have adopted High -Impedence based REFR-Protection.

see ANNEXURE-01

Inst

5.0 sec. see ANNEXURE-01 Inst

see ANNEXURE-01 ---

PACP

Recomended Relay Settings

RECOMMENDED RELAY SETTING CHART FOR 132/11.5kV, 20/25 MVA TRANSFORMER Relay Setting SI. No.

1

Type of Protection

Differential Protection (Restrained)

Relay Make / PROTECTION No. ANSI CODE

ABB - RET 670

Stage 1

CT Ratio / PT Ratio/ OTHER

Available setting range Parameter

Description

Available range

PSM

TMS/DMT (sec)

87T>

150/1A (132KV side)

Operation

on

----

----

----

(T2D1 )

2000/1A (11 kV Side)

IdMin

Setting of minimum differential operating current

0.10-0.60

0.25 * Ibase.

Inst

%Z = 12.5% ( TAKE FROM Name plate of trafo. )

End section 1

Cross-Over point b/w slope1 & Slope-2

0.2 - 1.5

1.25 * Ibase.

Vector group = YNyn0

Slope section 2

10.0 -50.0 %

40 * Ibias

1.0 -10

3 * Ibase.

30.0 -100.0 %

80 * Ibias

End section 2 Slope section 3 2

Differential Protection (Unrestrained) ,Stage 2

ABB - RET 670

87T>>

Differential current, High set (Unrestrained)

100- 5000 % of Ibase

10 * Ibase.

Cross blocking logic

OpCrossBlock

= on

-----

-----

Id2f / Id1f > (%)

2nd Harmonic restraint

5-100 % of fn

15%

Id5f / Id1f> (%)

5th Harmonic restraint

5-100 % of fn

25%

OpNegSeqDiff =

= on

-----

-----

NegSeqROA ABB - RET 670

64R LV

2000/1A (11 kV Side)

64R HV Restricted Earth fault Protection

Idmin (%) ROA

( Low impedance bsed.)

ABB - RET 670

64R LV

150/1A (132KV side)

2000/1A (11 kV Side)

(High Impedence based.)

64R HV

150/1A (132KV side)

Setting of minimum negative sequence (0.01 - 0.10 )* Iopr. differential current level Relay operate angle

Relay operate angle

Idmin (%)

Inst

0.04 * Iopr.

60 - 90 Degrees

60 °

4.0 -100.0

30%

60 - 90 Degrees

60 °

4.0 -100.0

30%

ROA

Relay operate angle

60 - 90 Degrees

60 °

U alarm

Operate voltage

( 2 -500 ) V

N/A

t Alarm

Operate time

0 - 60 sec

N/A

U trip

Operate voltage

( 5 -900 ) V

109.5 V

t trip

Operate time

-----

----

Rs

Series Resistor

10 -20000 Ohms.

396 ohms.

U alarm

Operate voltage

( 2 -500 ) V

N/A

t Alarm

Operate time

0 - 60 sec

N/A

U trip

Operate voltage

( 5 -900 ) V

63 V

t trip

Operate time

-----

----

Rs

Series Resistor

10 -20000 Ohms.

250 ohms.

Page 10 of 21

Remarks

see ANNEXURE-01

Idunre

IMinNegSeq =

Restricted Earth fault Protection

Setting of slope 2 stabilisation, (Slope 1 has fixed stabilization) Cross-Over point b/w slope2 & Slope-3 Setting of slope 3 stabilisation,

150/1A (132KV side) 2000/1A (11 kV Side)

Set the operation of Negative sequence differential protection

3

Recommended setting

Inst

Inst

This settings may not be applicable - while we have adopted High Impedence based REFR-Protection.

5.0 sec. see ANNEXURE-01 Inst

5.0 sec. see ANNEXURE-01 Inst

PACP

Recomended Relay Settings

RECOMMENDED RELAY SETTING CHART FOR 132/11.5kV, 20/25 MVA TRANSFORMER Relay Setting SI. No.

4

Type of Protection

Stand -by Earth fault Protection (HV Side)

Relay Make / PROTECTION No. ANSI CODE

ABB - RET 670

51s-EFR HV

CT Ratio / PT Ratio/ OTHER

150/1A (132KV side)

Available setting range

Recommended setting

Parameter

Description

Available range

PSM

IN1>/ Ib

Base Current Setting

1.0 -2500.0 % Ibase

20% * Ibase

Dir mode

-----

Non directional

( 4th-StageOFF)

Remarks

TMS/DMT (sec)

1st-stage

t11>

DT setting

0 - 60 Secs

----

1.0 sec.

NA

k11>

TMS

0.05 - 999

0.15 Secs

NI 0.15 Secs

IN2>/ Ib

Base Current Setting

1.0 -2500.0 % Ibase

15% * Ibase

Dir mode

-----

Non directional

see ANNEXURE-01 --2nd-stage

t1 2>

DT setting

0 - 60 Secs

----

1.5 sec.

NA

k1 2>

TMS

0.05 - 999

0.15 Secs

NI 0.15 Secs

IN3>/ Ib

Base Current Setting

1.0 -2500.0 % Ibase

10% * Ibase

Dir mode

-----

Non directional

3rd-stage

t1 3>

DT setting

0 - 60 Secs

----

2.0 sec.

NA

k1 3>

TMS

0.05 - 999

0.15 Secs

NI 0.15 Secs

Page 11 of 21

see ANNEXURE-01

PACP

Recomended Relay Settings

RECOMMENDED RELAY SETTING CHART FOR 132/11.5kV, 20/25 MVA TRANSFORMER Relay Setting SI. No.

5

Type of Protection

Stand -by Earth fault Protection (LV Side)

Relay Make / PROTECTION No. ANSI CODE

ABB - RET 670

51s-EFR LV

CT Ratio / PT Ratio/ OTHER

600/1A ( in NGR )

Available setting range Parameter

Description

Available range

PSM

IN1>/ Ib

Base Current Setting

1.0 -2500.0 % Ibase

15% * Ibase

Dir mode

-----

Non directional

( 4th-StageOFF)

6

Under Frequency . Protection.

ABB - RET 670

81.U

t11>

DT setting

0 - 60 Secs

----

2.0 sec.

NA

k11>

TMS

0.05 - 999

0.15 Secs

NI 0.15 Secs

IN2>/ Ib

Base Current Setting

1.0 -2500.0 % Ibase

25% * Ibase

Dir mode

-----

Non directional

Over Frequency . Protection.

ABB - RET 670

81.O

see ANNEXURE-01

2nd-stage

t1 2>

DT setting

0 - 60 Secs

----

1.5 sec.

NA

k1 2>

TMS

0.05 - 999

0.15 Secs

NI 0.15 Secs

IN3>/ Ib

Base Current Setting

1.0 -2500.0 % Ibase

30% * Ibase

Dir mode

-----

Non directional

3rd-stage

t1 3>

DT setting

0 - 60 Secs

----

1.0 sec.

NA

k1 3>

TMS

0.05 - 999

0.15 Secs

NI 0.15 Secs

132KV / 110 Volts.

Operation mode

on /Off

on.

Ubase (KV)

Base voltage setting

0.05 - 2000 volts.

132 KV

Start Freq.

Freq setting / start value.

35 -75 Hz.

48.8 Hz.

Int_Bloc_Level

Internal_Blocking _Level in % Of Ubase

0 -100 % Of UB

50%

Time delay operate

0 -60 sec.

0.2 sec.

Time delay Reset

0 -60 sec.

0.0 sec.

Time delay Restore

0 -60 sec.

0.0 sec.

Restore freq.

45 - 65 Hz.

50.10 Hz.

Timer Operation

132KV / 110 Volts.

f>

see ANNEXURE-01

see ANNEXURE-01

DT/ Voltage based

DT

----

Unom

50 -150 % Ub

100

N/A

Umin

50 -150 % Ub

90

N/A

Exponent .

0.0 - 5.0

1

N/A

Tmax.

0.01 -60 sec.

1

N/A

Tmin

0.01 -60 sec.

1

N/A

Operation mode

on /Off

off

Ubase (KV)

Base voltage setting

0.05 - 2000 volts.

132 KV

Start Freq.

Freq setting / start value.

35 -75 Hz.

51.20 Hz.

Int_Bloc_Level

Internal_Blocking _Level in % Of Ubase

0 -100 % Of UB

50%

Time delay operate

0 -60 sec.

0.0 sec.

Time delay Reset

0 -60 sec.

0.0 sec.

Page 12 of 21

Remarks

TMS/DMT (sec)

1st-stage

f<

6

Recommended setting

see ANNEXURE-01

PACP

Recomended Relay Settings

RECOMMENDED RELAY SETTING CHART FOR 132/11.5kV, 20/25 MVA TRANSFORMER Relay Setting SI. No.

6

Type of Protection

Rate of change of Frequency . Protection.

Relay Make / PROTECTION No. ANSI CODE

ABB - RET 670

Df /dt

CT Ratio / PT Ratio/ OTHER

132KV / 110 Volts.

f>

6

Over Fluxing (Over excitation)

ABB - RET 670

99 (24)

220KV / 110 Volts.

Available setting range

Recommended setting TMS/DMT (sec)

Parameter

Description

Available range

Operation mode

on /Off

off

Ubase (KV)

Base voltage setting

0.05 - 2000 volts.

132 KV

Start Freq. Gradient.

Freq .Gradient.

-10 - 10 Hz/sec..

0.5 Hz /sec.

Int_Bloc_Level

Internal_Blocking _Level in % Of Ubase

0 -100 % Of UB

50%

Operate Time ( tTrip )

0 -60 sec.

0.2 sec.

Time delay Reset

0 -60 sec.

0.0 sec.

Time delay Restore

0 -60 sec.

0.0 sec.

Restore freq.

45 - 65 Hz.

49.90 Hz.

V/Hz>

Voltage / Freq.

100 - 180% x U/f

110% x U/f

t alarm

oprtng. Time

0-9000 sec.

----

T-alarm_level

Alarm operate level

50 -120%

100%

Voltage / Freq.

100 - 200% x U/f

140% x U/f

0 - 9000 sec.

1500

1800

0 - 60 secs

4 sec

7

0 - 60 secs

0.1

0.1

0.00-200 ohms.

0

0.1 -9000 sec

1200

INVERSE/ IEEE / TAILOR MADE.

IEEE

V/Hz>> tmax. tmin tr-pulse X-leakage t-cooling CurveType

max. trip delay for I curves min. trip delay for I curves length of Pulse for trip Leaakage reactance of trafo. Winding. cooling time constant for Trao. curve selection.

Page 13 of 21

PSM

Remarks

see ANNEXURE-01

see ANNEXURE-01

5sec.

1200 sec.

see ANNEXURE-01

PACP

Recomended Relay Settings

RECOMMENDED RELAY SETTING CHART FOR 132/11.5kV, 20/25 MVA TRANSFORMER Relay Setting SI. No.

7

Type of Protection

Local Breaker Back-up

Relay Make / PROTECTION No. ANSI CODE

ABB - RET 670

50 LBB

CT Ratio / PT Ratio/ OTHER

150 / 1A (132KV side)

Available setting range

Recommended setting

Parameter

Description

Available range

PSM

Operating mode

backup trip mode

1 out of 4/ 2 out of 4 / 1 out of 3

1 out of 3

Retrip-mode

t1 >

Operate Ph. Current in % of Ibase Operate Residual. Current in % of Ibase time delay of re-trip

IP > IN >

8

9

Residual -Over voltage Voltage Protection Protn.

Back-up Overcurrent/ Earth fualt protection ( Non-dir / Dir )

ABB - RET 670

REX 521 H-02

TMS/DMT (sec)

re-trip -Off 5-200%

10%

2-200%

10%

0-60sec.

0 sec.

59N

132KV/√3 / 110V/√3

Operation Mode

----

0n , STAGE-1

UB =

Open-delta Voltage

CurveType

DT/C-A/C-B/C-C

DT

51 / 50 / 51N / 67 / 67N

see ANNEXURE-01

0 sec.

see ANNEXURE-01

U1 >

START VOLTAGE

1- 200 % UB

30 % UB

t1 >

Definite Time Delay

0 - 6000 sec.

5 sec.

5 sec.

t1 min >

Operating Time for I curves

0 - 60 sec.

5 sec.

NA

k1 >

TMS

0.05 - 1.10

0.05

NA

HystAbs1

Absolute Hysteresis in% of Ubase.

0 -100 % UB

0.5 % UB

Operation Mode

----

0n , STAGE-2

see ANNEXURE-02

CurveType

DT/C-A/C-B/C-C

DT

U2 >

START VOLTAGE

1- 100 % UB

45 % UB

t2 >

Definite Time Delay

0 - 6000 sec.

5 sec.

5 sec.

t2 min >

Operating Time for I curves

0 - 60 sec.

5 sec.

NA

k2 >

TMS

0.05 - 1.10

0.05

NA

HystAbs2

Absolute Hysteresis in% of Ubase.

0 -100 % UB

0.5 % UB

150/1A (132KV side)

Operation Mode

Not in use / DT/ NI/VI / c-2 ETC. ( 1 to 15 )

DT =01

31>

NOC3Low (51)

31>

Current setting (I/ In)

0.10 - 5.00 xIn.

0.7

Operate time ( in DT)

0.05 - 300 Secs

0.05

0.05 - 1.00

0.05

0.5 - 15

0.5

Not in use / DT / inst..

Inst. = 02

31>>

Current setting (I/ In)

0.10 - 40 xIn.

2

Operate time ( in DT Mode)

0.05 - 300 Secs

0.05

time Multiplier ' K '( in IDMT -mode ) IEEE- time DAIL in IDMT -mode NOC3High ( 50 / 51 )

Operation Mode 31>>

Remarks

IDMT

DT- 0.05 SECS. see ANNEXURE-02

Page 14 of 21

PACP

Recomended Relay Settings

RECOMMENDED RELAY SETTING CHART FOR 132/11.5kV, 20/25 MVA TRANSFORMER Relay Setting SI. No.

Type of Protection

Relay Make / PROTECTION No. ANSI CODE

REX 521

CT Ratio / PT Ratio/ OTHER

DEF2Low ( 67N / 51N )

Available setting range Parameter

Description

Available range

PSM

Operation Mode

Not in use / DT/ NI/VI / c-2 ETC.

DT =01

Io >->

Operation Criteria

67N,51N etc.., (1 to 05)

4 = Non-directional Io>

-----

Operation direction

forward / Reverse

forward=0

N/A

Operation Charecteristics.

IoSin(phi) / IoCos(phi) ( 0,1)

0

N/A

Basic Angle

-90 deg to 60 deg.

-90 deg

N/A

Io >

Current setting (Io/ In)

0.01 - 5.00 xIn.

0.075

Uo>

REX 521

REX 521

DEF2High ( 67N )

DOC6Low ( 67 )

Recommended setting

Start voltage

2.0 - 100 % of Un.

75%

Operate time ( in DT)

0.10 - 300 Secs

0.1

Operation Mode

Not in use / DT/ NI/VI / c-2 ETC.

DT =01

Io >>->

Operation Criteria

67N, etc.., (1 to 05)

0 = Basic angle & Uo

-----

Operation direction

forward / Reverse

forward=0

---

Operation Charecteristics.

IoSin(phi) / IoCos(phi) ( 0,1)

0=Io*sin(phi)

----

Basic Angle

-90 deg to 60 deg.

-90 deg

-----

Io >

Current setting (Io/ In)

0.01 - 5.00 xIn.

0.075

Uo>

Start voltage

2.0 - 100 % of Un.

5%

Operate time ( in DT)

0.1 - 300 Secs

0.1

intermittent EFR

Active / Not-active (0,1)

0

---

Operation Mode

Not in use / DT/ NI/VI / c-2 ETC.

DT =01

3I >_>

Operation direction

forward / Reverse

forward=0

---

Operation Charecteristics.

IoSin(phi) / IoCos(phi) ( 0,1)

0=Io*sin(phi)

---

Basic Angle

0 deg to 90 deg.

60 deg

---

Io >

Current setting (Io/ In)

0.05 - 40 xIn.

0.75

time Multiplier ' K '( in IDMT -mode )

0.05 - 1.00

0.05

Operate time ( in DT)

0.05 - 300 Secs

0.05

Page 15 of 21

Remarks

TMS/DMT (sec) see ANNEXURE-02

see ANNEXURE-01

N/A

3I >>_>

IDMT

PACP

Recomended Relay Settings

RECOMMENDED RELAY SETTING CHART FOR 132/11.5kV, 20/25 MVA TRANSFORMER Relay Setting SI. No.

Type of Protection

Relay Make / PROTECTION No. ANSI CODE

REX 521

CT Ratio / PT Ratio/ OTHER

DOC6High ( 67 )

Available setting range Parameter

Description

Available range

PSM

intermittent EFR protection

Disabled / Enabled(0,1)

0

---

Operation Mode

Not in use / DT/ Inst.

Inst. = 02

3I >>_>

Operation direction

forward / Reverse

forward=0

---

Operation Charecteristics.

IoSin(phi) / IoCos(phi) ( 0,1)

0=Io*sin(phi)

---

Basic Angle

0 deg to 90 deg.

60 deg

---

Io >

Current setting (Io/ In)

0.05 - 40 xIn.

0.05

Non directional Operation

when the dir. Cannot be determined ( 0, 1 )

0

----

Operate time ( in DT)

0.05 - 300 Secs

0.05

Disabled / Enabled(0,1)

0

---

DT -ALARM / trip stage

U< -

40 -120 V 0 - 99 hrs. 40 -120 V 0 - 99 hrs.

85 volts. 3.0 sec. 77 volts. 1.0 sec.

DT -ALARM / TRIP stage

U> -

60 -160 V 0 - 99 hrs. 40 -120 V 0 - 99 hrs.

115 volts. 3.0 sec. 121 volts. 1.0 sec.

intermittent EFR protection 10

Under-Voltage Relay.

RXEG 21

27

132000V/√3 / 110V/√3

Operation Mode U< Alarm t > alarm U< Trip t > Trip

11

Over-Voltage Relay.

RXEG 21

59

132000V/√3 / 110V/√3

Recommended setting

Under voltage setting. time setting.(DT) Under voltage setting. time setting.(DT)

Operation Mode U> Alarm t > alarm U> Trip t > Trip

Under voltage setting. time setting.(DT) Under voltage setting. time setting.(DT)

Page 16 of 21

Remarks

TMS/DMT (sec)

3I >>_>

see ANNEXURE-01

see ANNEXURE-01

APPM-MDP

Recomended Relay Settings

RET-670 & REX-521 RELAY - DETAILED DESCRIPTION FOR SETTING BASIS. 1)

87T -TRAFO. DIFFERENTIAL PROTECTION:

The charecteristic for this protection function as adopted in the relay is as shown below.

a) Initial setting:( Idmin) ; --- This setting covers the un-balance created in the differential operating current by the On load Tap changer. In our case the the Tap changer limits are +10% to -15% , and hence the mean tap value : [ 10 +(-15) ] / 2 = - 2.5% and so, the Hv -amps @ mean tap value =[109.35 / (1-0.0250 ] = 112.154 Amps, which corresponds to 2.56% variation in the HV-currents when mean value is considered. Also,in practice typically the initial minimum differentialpick up value for power trafos with OLTC is set between 30% - 40% . However, RET-670 is in-built with OLTC compensation factor and it is possible to set the Id(min) to more sensitive pick up value between ( 15% to 20% ) .Thus we preferred to se the Idmin = 0.25 of Ibase. b) Endsection-1 setting: ; --- This is the most sensitive part of the charecteristic.Uncompensated OLTC currents are the reason for the existing of false diff currents in this region. so, the slope in this section is always zero.The end lit of this section is set at 1.25 after ensuring the risk of higher false differential currents relatively low.Also,this is the defualt setting set in the RET-670. c) Slopesection-2 , End section-2 ,Slopesection-3 ; --- These settings are typically adopted to form the Differntial -curve as shown above. The curve with these setting is suitable for various applications as per the Technical -reference manual-rev-b (p-116) .Also, the basis for these settings are as descibed in the technical reference manuals. d) Unrestrain -high set ,Idunre ; --- This setting by defualt set at 10.This setting ensures the operation instantaneously, as without any doubt this big differential current occurs only due to internal fualts. Also, this by-passes the harmonic test in its operation and so, called unstabilised operation.( Technical -reference manual-rev-b (p-115) 2)

64R-HV & 64R-LV -TRAFO.HIGH IMPEDENCE BASED RESTRICTED EARTH FUALT PROTECTION : It is a common known fact that ( compared to Low impedence based REFR protection) , High impedence based protections are highly sensitive, accurate & fast operating. Since, high impedence based protections are current / voltage based , and hence makes use of METROSIL & STABILIZING RESISTOR in it's circuit is evident due to high-impedence occurance. The settings for Metrosil and Stablising resistor are as under : CTR -HV = 150 / 1A . R nct = ( as per the field test data ) 2.0 ohms. Rct= 2.0 ohms.

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APPM-MDP

Recomended Relay Settings

Rs = Us / Ir ----- 1 Rs = The resistance of the stabilizing circuit. Us = The stabilizing voltage of the Relay.. Ir = The setting value of the Relay..

Ir = The setting value of the Relay..

Us = If / CTR [ Rct + Rlead ] -------- 2 If = Max. expected Through fault current. CTR = phase & nuetral common CT Ratio. Rct = Internal CT secondary resistance of the Circuit. Rl = R of Longest loop of secondary circuit. Uk > = 2 * Us --------- 3 , where Uk = Knee point voltage of the Relay. And factor 2 is used when no operate delay permitted for protection. I prim = CTR* [ Ir + Inr + m x Ie ] ----- 4 Iprim = prim. Operating Current of the relay. Ir = setting value of the Relay. Inr = Current through the Non-Linear Resistance m = no of CT's in the circuit. / no of CT's in parallel. Ie = Excitation current of the CT @ Us. Ie = 0.5 * I0 ------- 5 Io = Excitation current of the relay @ Uk Ir recommended > = m x Ie = m x 0.5 x Io ( as per the technical manual ) Also, as per the Relay manuals and pratice , If ( max. thro fualt current ) = 16 x IfL ---- for small Transformers. = 12 x IfL ---- for Big Transformers. = 6 x IfL ---- for Generators. IfL ---- > Full load current of the Transformer /Generator. Also, the sensitivity requirements for the protection are jeopardize if the magnetizing current of the CT's at Vk is too high. The Iprim Vaue at which the Relay operates at certain settings can be calculated using the formula. As in the eqn --- 4. TRANSFORMER DATA : MVA = 20 /25 ONAN /ONAF KV -Rating. : 132 /11.5 KV % Z = 12.5 P.u ON 20 MVA BASE. Vector group : YNyn. Tap Change Limit : +10 % to -15% @ 1.25% Nct -Ratio = 150 /1A Uk -Nct = 150 Volts. ( as phase CT's are designed for Uk> 400volts,Hence the chances getting saturated is minimum.) Excitation current for NCT < 30 mA @ Vk / 2.

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APPM-MDP

Recomended Relay Settings

Calculations for REFR -HV : Rnct = 2.0 ohms , Rlead = 2.0 ohms. & Rct(ph) = 4.0 ohms. ( for calculations Rct(ph) shall be taken or which ever is Higher.) Nct -Ratio = 150 /1A Uk -Nct = 150 Volts. ( as phase CT's are designed for Uk> 400volts,Hence the chances getting saturated is minimum.) Excitation current for NCT < 30 mA @ Vk /2 ( considering the worst case ). IfL -HV = 109.35A , CTR= 150 If = ( %Z ) x IfL = 12.5 x 109.35 = 1367 A ( Max. expected through fault current expected. ) Uk = (required) = 2 x Us. = 2 x If / CTR [ Rct + Rlead ] = 2 x (1367 / 150) [4 +2 ] = 109.36 volts.=110 V (approx.) As Uk is >>> than 150 V as per the Trafo. Name plate data for NCT.The operation of protection would be ensured perfectly. And is not a case dependent. Us =Uk /2 = 54.68 volts.=55 V (approx.) Now, since the RET-670 adopts High-Impedence scheme with voltage as operand. Hence, the Stabilizing Resistor , Rs= 250 ohms. & Us>= 63volts. The setting to adopted is = 115% of Us> = 1.15 x 55 = 63 (Approx.) volts. Ip(prim) = (Sentivity current measured) = CTR { Ir + I_nlr + n x Ie } Ir = Current through the Relay @ voltage Us> = 63/250 = 252 mA . Inlr = Current through the Non- Linear Resistor = (from the graph.) = 5 mA. nxIe = no. of CT's and their average Excitation currents. = (0.0504+3x0.0252) = 126mA.(approx.) Ip(prim) = (Sentivity current measured) = CTR { Ir + I_nlr + n x Ie }= 150{ 252+5+126 } = 57.45 A. This is well below the value minimum fualt current, and only constitute 38.3 % of Rated CT current. Also, As, per the above description , The Ir >= m x 0.5 x Io = 4 x 0.5 x ( 0.030 x 2 ) = 0.12 A so, the setting is safe. Hence, the Stabilizing Resistor , Rs= 250 ohms. & Us>= 63volts. Calculations for REFR -LV : Rnct = 4.0 ohms , Rct (ph) = 10.0 ohms. & Rlead = 2.0 ohms.( for calculations Rct(ph) shall be taken or which ever is Higher. ) IfL -LV = 1255.15A , CTR= 2000/1A Nct -Ratio = 2000 /1A Uk -Nct = >300 Volts. ( as phase CT's are also,designed for Uk> 300volts,Hence the chances getting saturated is minimum.) Excitation current for NCT < 30 mA @ Vk / 4. If = ( %Z ) x IfL = 12.5 x 1255.15 = 15690 A ( Max. expected through fault current expected. ) Uk = (required) = 2 x Us. = 2 x If / CTR [ Rct + Rlead ] = 2 x (15690 / 2000) [ 10 +2 ] = 188.3 volts.=189 V (approx.) As Uk is >>> than 300 V as per the NGR. Name plate data for NCT.The operation of protection would be ensured perfectly. And is not a case dependent. Us =Uk /2 = 94.14 volts.=95 V (approx.)

Hence, the Stabilizing Resistor , Rs= Us/Ir. = 95 / 0.24 =395.83 = 396 Ohms (approx.) Now, since the RET-670 adopts High-Impedence scheme with voltage as operand. The setting to adopted is = 115% of Us> = 1.15 x 95 = 109.5 (Approx.) volts. Calculation of Stabilizing Resistor : As per manuals of RET , This can be directly selected to a value Rs=396 ohms . Now , this value of resistor should satisfy the below eqn. Ip(prim) = (Sentivity current measured) = CTR { Ir + I_nlr + n x Ie } Ir = Current through the Relay @ voltage Us> = 109.5/396 = 276.5 mA . Inlr = Current through the Non- Linear Resistor = (from the graph.) = 5 mA. nxIe = no. of CT's and their average Excitation currents. = (0.0544+3x0.0544) = 218mA.(approx.) Ip(prim) = (Sentivity current measured) = CTR { Ir + I_nlr + n x Ie }= 2000{ 276.5+5+218 } = 999.0 A. This is well below the value minimum fualt current, and only constitute 49.95 % of Rated CT current. Also, As, per the above description , The Ir >= m x 0.5 x Io = 4 x 0.5 x ( 0.030 x 4 ) = 0.24 A so, the setting is safe. Hence, the Stabilizing Resistor , Rs= 396 ohms. & Us>= 109.5 volts.

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APPM-MDP

Recomended Relay Settings

3)

51Ns -HV & LV : The stand by earth-fualt protection , is mainly to Protect the NGR from over heating due to Fualt current exceeding the rated current rating of the NGR. .So, the settings adopted have to be set in Definite time mode depending upon it's thermal current rating of the Transformer. The rated duty of the NGR is our case is 600A for 30 secs. And hence , the settings should be planned such that the HV - S/b EFR should trip HV-Breaker , and LV - S/b EFR should trip LV -Breaker , compeletely isolating the Transformer from the circuit. However , as discussed in the prior meeting held with Mr.B.D.Shaw,if the Lower rating -NGR that are existing in the System , then it's setting should be minimised to the value of Lower -rating NGR or 90% of that. We have attached a document on S/B EFR Protection with this for your reference. Hence, the setting should be adopted for HV S/B EFR : CTR= 150 /1A , Io > setting= approx.( 15 % - considering the Lowest rating NGR ,rating = 100A ,Else 85% - considering the rated ampacity of the NGR.) Time setting: definite time , and should be with in the Rated duty of NGR i.e 3.0 secs. LV S/B EFR : CTR= 600 /1A , Io > setting= approx.( 15 % - considering the Lowest rating NGR ,rating = 100A .)

4)

99 (24) : Over fluxing Protection. Actual set limits for this protection should be in accordance with the data submitted by the ' Trafo. Manufacturer. " . However , the default settings of as in the relay , suits for most of the applications. These default settings programmed at ABB Factory , after a detailed study of Most -common and most versatile applications. As pe the TRAFo. " Permissible Over-excitation Curve " ( attached with mail.) . Some Important Factors / Notes for Over fluxing Protection: 1) Over excitaion occurs from the excessive applied voltage, possibly in combination with below normal Frequency. Such conditions are very often , when Transformers are directly connected to the Generators. 2) Bmax is directly proportional to the Induced voltage., as E = 4.44 x f x n x Bmax . A 3) The calculation of the relative ( M ) ,is based on the V/Hz ratio.. 4) As per IEC 60076-1 , All transformers shall be capable of operating continuously at 10% above rated voltage. On that basis the setting range is 100 - 150%. & if the User does not know what exactly to be set , then th e standard IEC-60076 -1 section-4.4 suggests defualt value V/Hz > = 1.10 p.u. 5) As long as the E/f or V/F did not cross the relative value (M) set of the relay, the Trafo. Is not overexcited. The relative over excitation is thus defined as Over excitaion = M - V/Hz > 6) Operatin Time of the Overexcitation Protection : The most famous Law ,so called IEEE Law approximates a square Law and has been choosen based on the analysis of the various transformers over excitation capability charecteristics. They can match a well a transformer core capability. t op = 0.18 x k [ M - V/Hz>)2 ….= 0.18 x k / ( Overexcitaton ) . Where: M -- is the , Mean value in the interval from t=0 to t=top . V/Hz > ---- is the Max. continously allowed voltage at no -Load and rated Frequency , in p.u . & K ----- is the time multiplier setting for the inverse time functions as usual & selects one curve frim the family of Curves. Since , from - " Trfo. Data curves " over Excitation of beyond 110% is not allowed so, for Our setting of V/Hz > 110 % of Vr /fr is set and is same as default. Also, the Alarm setting in the relay is in-built and is 2% less than the set value , with a definite time delay of set limit - Tmin. And all other settings are as in the setting chart. We have attached a " over -Excitation Protection basis for your reference along with the Trafo. Over-Excitaion Curve.

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APPM-MDP

Recomended Relay Settings

5)

81.O & 81.U - or df/dt Protection. : ( RET-670 ) The basis for this settings when derived from the over excitation limits ( V/Hz - ratio limits) along with the Under & Over voltage set limits , The values found to be extremely high or extremely low , such as ( f > becomes 55 Hz. & f < becomes 36 Hz.) ,Hence, these limits are set in accordance with the ELECTRICITY Regulatory Rules bound to that region. We request M/s Customer to do this setting at site.However, we maintained the same defualt settings for this application.

6)

27 & 59 - Protection. : ( REXEG-21 ) These settings are based on the common practice adopted at most of the installations. Also, the same values are acceptable to most of the Electricity Boards across India. The values adopted are --- 110% of the 110V = 121 volts. ( PT -secondary Rated-value ) --- for Over voltage Limits & ---- 70% of the 110V = 77 Volts ( PT -secondary Rated-value ) --- for Under voltage Limits

7)

50/51, 50N/51N, 67 & 67N - Protection. : ( Rex-521) These settings are based on the relay co-ordination study , and direction is also based on the study whre in if the non-directional Overcurrent grading is set to follow relay cordination timings , then the Directional - OCR shall be graded fastly to look towards that direction where the former gives graded timing with a substantial time delay. Also, the current settings for these Relays are the full-load current of the Equipment / Feeder.So, we have achieved in this settings, whreas the setting of TMS , needs a DETAILED STUDY.

Calculations for REFR -LV : Rnct = 4.0 ohms , Rct (ph) = 10.0 ohms. & Rlead = 2.0 ohms.( for calculations Rct(ph) shall be taken or which ever is Higher. ) IfL -LV = 15690 A , CTR= 2000/1 A Nct -Ratio = 2000 /1A Uk -Nct = >300 Volts. ( as phase CT's are also,designed for Uk> 300volts,Hence the chances getting saturated is minimum.) Excitation current for NCT < 30 mA @ Vk / 4. If = ( %Z ) x IfL = 12.5 x 1255.15 = 15690 A ( Max. expected through fault current expected. ) Uk = (required) = 2 x Us. = 2 x If / CTR [ Rct + Rlead ] = 2 x (15690 / 2000) [ 10 +2 ] = 188.3 volts.=190 V (approx.) As Uk is >>> than 300 V as per the NGR. Name plate data for NCT.The operation of protection would be ensured perfectly. And is not a case dependent. Us =Uk /2 = 95 volts.=95 V (approx.) Now, since the RET-670 adopts High-Impedence scheme with voltage as operand. The setting to adopted is = 115% of Us> = 1.15 x 101 = 117 (Approx.) volts. Calculation of Stabilizing Resistor : As per manuals of RET , This can be directly selected to a value Rs=450 ohms . Now , this value of resistor should satisfy the below eqn. Ip(prim) = (Sentivity current measured) = CTR { Ir + I_nlr + n x Ie } Ir = Current through the Relay @ voltage Us> = 117/450 = 260 mA . Inlr = Current through the Non- Linear Resistor = (from the graph.) = 5 mA. nxIe = no. of CT's and their average Excitation currents. = (0.0544+3x0.0544) = 218mA.(approx.) Ip(prim) = (Sentivity current measured) = CTR { Ir + I_nlr + n x Ie }= 3000{ 260+5+218 } = 1449.0 A. This is well below the value minimum fualt current, and only constitute 48.3 % of Rated CT current. Also, As, per the above description , The Ir >= m x 0.5 x Io = 4 x 0.5 x ( 0.030 x 4 ) = 0.24 A so, the setting is safe. Hence, the Stabilizing Resistor , Rs= 450 ohms. & Us>= 117 volts.

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