relay settings.pdf

7/25/2019 Relay Settings.pdf

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10 MW Grid Tied SPV Plant at Charanka(GJ).

1.0 INTRODUCTION

2.0 OBJECTIVE

3.0 REFERENCE DRAWINGS/DOCUMENTS

4.0 SYSTEM DESCRIPTION

5.0 STUDY APPROACH / BASIS & ASSUMPTIONS

6.0 RELAY IDENTIFICATION TABLE

7.0 ATTACHMENT




1.0 INTRODUCTION This document represents the relay settings for 10 MW GridTied SPV Plant atCharanka(GJ)

2.0 OBJECTIVE

A.

The Relay setting and Coordination analysis is conducted to recommend the relay settings

and achieve proper coordination between relays installed at 10MW Solar Plant.

The Relay coordination study is performed to determine various relay settings undernormal operating condition and to ensure:

a. Sensitivity to over current and earth faults under minimum and maximum faultconditions.

b. Selectivity of relays.c. Stability for non operating conditions.

3.0 REFERENCE DRAWINGS/DOCUMENTS

a) 66kV Feeder C&R Panel,

b) 66kV Transformer Bay C&R Panel,

4.0 SYSTEM DESCRIPTION The power distribution diagram is shown in the Single Line Diagram. As shown, 11kVvoltage is generated through inverter transformer which is further stepped up to 66 kv andfed to grid.

5.0 STUDY APPROACH / BASIS & ASSUMPTIONS The phase Fault level on 66kV bus is 10kA.

Grading margin of 0.25 seconds has been considered between outgoing and incomerfeeders.

Back-up protection for O/C and E/F has been considered upto two levels only.

Time of operation for Normal Inverse relay at 1.0 TMS (as per IEC)

t = β / [(I/Is)α - 1]

Where,t = Tripping TimeI = Fault currentIs = Inverse time over current pickup,

TMS = Time Multiplier SettingI/Is = Plug setting Multiplier = PSM

α = 0.02, β = 0.14 For Normal Inverseα = 1, β = 13.5 For Very Inverseα = 2, β = 80 For Extremely Inverse




6.0 RELAY IDENTIFICATION TABLE

SN RELAY NO. DESCRIPTION REMARKS

1 50 Instantaneous Over current

2 50N Instantaneous Earth fault

3 51 IDMT Over current

4 51N IDMT Earth fault5 67 Directional Over current

6 87 Transformer Differential Protection

7.0 ATTACHMENTS

Attachment-1: Summary of Relay settings

Attachment-2: Overcurrent and Earth fault Relay Co-ordination curves



ect : 10 MW Grid Tied SPV Plant at Charanka(GJ) ATTACHMENT‐1

Summary Sheet

SR. No. Service

Rated

voltage

(Volts)

Rating

(kW/kVA)

CT

Ratio Symbol Service Manuf. Model No. Parameter Plug Setting Time D

1 66KV OUTGOING FEEDER 66 KV 300‐600/1 51 IDMT O/C S IE ME NS 7 SR12 06 0.05 to 2.5 In 0.025…

51N IDMT E/F 0.005 to 0.5 In

67 DIR O/C 0.05 to 2.5 In

67N DIR E/F 0.05 to 2.5 In

2 T RA NS FO RMER‐1 66 K V 6000 KVA 60/1 51 IDMT O/C S IE ME NS 7 SR11 03 0.05 to 2.5 In 0.025…

50 DT O/C 0.05 to 50 In

50N DT E/F 0.05 to 5 In

87 DIFFERENTIAL PROTECTION S IE ME NS 7 SR24 22 MULTIPLIER

INITIAL SETTING 0.1….2In

1ST BIAS SLOPE SETTING 0.1….0.7In

1ST BIAS SLOPE LIMIT 1.2…20 In

2ND BIAS SLOPE SETTING 1…2 In

DELAY SETTING

3 OUTGOING TO 66 KV TRANSFORMER 11 KV 400/1 51 IDMT O/C ABB REJ 601 0.2…1 In 0.025…

51N IDMT E/F 0.05…5 In 0.025…

4 INCOMER TO 11KV BOARD 11 KV 400/1 51 IDMT O/C ABB REJ 601 0.2…1 In 0.025…

51N IDMT E/F 0.05…5 In 0.025…

5 INCOMER TO RMU 11 KV 100/1 51 IDMT O/C ABB REJ 601 0.2…1 In 0.025…

50 DT O/C 0.05…5 In 0.025…

50N D T E/F 0.05 to 50 In

Relay Description Relay Setting Range



Project : 10 MW Grid Tied

SPV Plant at Charanka(GJ)

ATTACHMENT‐2.1 Sheet 1 of 2

OVER CURRENT CURVES

0.01

0.1

1

10

100

1000

10000

100000

1 10 100 1000 10000

TIME(SEC)

MVA

66kV OUTGOING

6MVA TRAFO. PRIMARY

11 KV OUTGOING

11

KV

INCOMER

1.5MVA

TRAFO

PRI





ATTACHMENT‐2.2 Sheet 2 of 2

EARTH FAULT CURRENT CURVES

0.01

0.1

1

10

100

1000

10000

100000

1 10 100 1000 10000

TIME(SEC)

If(A)

6

MVA

TRAFO

PRI

66kV LINE

RMU

I/C

11

KV

INCOMER

11

KV

OUTGOING





ATTACHMENT 3

CALCULATION

Sheet 1

66KV OUTGOING LINE

Setting Range =

CT Ratio = 300 / 1A

Load Current = 300.0 A

Fault Current = 10.00 kA

Current Setting = 80 %

Relay Characteristics = Normal Inverse

IDMT O/C Relay settin g

Multiples of plug setting current = = 41.67

300 x 0.80

Relay opert'n time@ 41.67 times PS and 1.0 TMS = 2.27 sec

Operating time of downstream O/C relay = 0.05 sec

Allowing a grade margin of 250 msec,

Operating t ime required = 0.300 sec

TMS = 0.30 sec = 0.13

2.27 sec

Actual Opert'n time = 2.27 x 0.13 = 0.29 sec

Recommended Settings :

Current Setting = 80%

TMS = 0.13

IDMT E/F Relay settin g


300 x 0.15


Operating time of downstream E/F relay (To Trafo feeder) = 0.05 sec


Operating time required = 0.30 sec

TMS = 0.30 sec = 0.132

2.3 sec

Actual Opert'n time = 2.27 x 0.130 = 0.29 sec



TMS = 0.13

10000

10000

1)( −

=α

β

PSM t

1)( −

=α

β

PSM t





ATTACHMENT 3

CALCULATION

Sheet 2

O/G to 6.0MVA TRANSFORMER

Relay, Make = SIEMEN'S 7SR1103

Setting Range = 0.1 to 40 In

CT Ratio = 60 / 1A

Load Current = 52.5 A

Fault Current = 0.62 kA

Current Setting = 110 %

Relay Characteristics = Normal Inverse

IDMT Relay sett ing (51)

Fault current at the secondary side of 66/11kV, 6000 kVA transformer = 3.71 kA

(Considering Z = 8.5% for 6000 KVA Transformer)

Reflected current on primary side = (66 kV) = 618 A


60 x 1.10


Operating time of downstream O/C relay = 0.55 sec


Operating time required = 0.80 sec

TMS = 0.80 sec = 0.26

3.06 sec

Actual Opert'n time = 3.06 x 0.26 = 0.80



TMS = 0.26

Highset Setting (50)

Relay Setting range = 0.1 to 40 In

Time delay = 0-150 sec

The relay has to trip for a fault in the primary side of Trafo i.e @ 10.00 kA

The relay shall be set such that it does not operate for the reflected down stream fault of 0.6175 kA @

66kV side

The minimum fault current for the relay to operate

(Considering 20% margin) = 0.6175 x 1.2 times = 0.741 kA


60 x 1.00



Time Delay (DT) = 0.05 sec

E/F Relay Setting (50N)

Relay Setting range =

Time delay = 0 to 64 sec

Current setting = 20%

Time Delay (DT) = 0.05 sec

The relay has to operate with minimum time delay for ground fault in the primary side of Transformer

618

0.741

1)( −

=α

β

PSM t

relay settings.pdf

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