Relay Settings.pdf
Transcript of 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
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10 MW Grid Tied SPV Plant at Charanka(GJ).
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
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10 MW Grid Tied SPV Plant at Charanka(GJ).
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
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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
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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
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Project : 10 MW Grid Tied
SPV Plant at Charanka(GJ)
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
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Project : 10 MW Grid Tied
SPV Plant at Charanka(GJ)
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
Multiples of plug setting current = = 222.22
300 x 0.15
Relay opert'n time@ 222.22 times PS and 1.0 TMS = 2.27 sec
Operating time of downstream E/F relay (To Trafo feeder) = 0.05 sec
Allowing a grade margin of 250 msec,
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
Recommended Settings :
Current Setting = 15%
TMS = 0.13
10000
10000
1)( −
=α
β
PSM t
1)( −
=α
β
PSM t
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Project : 10 MW Grid Tied
SPV Plant at Charanka(GJ)
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
Multiples of plug setting current = = 9.36
60 x 1.10
Relay opert'n time@ 9.36 times PS and 1.0 TMS = 3.06 sec
Operating time of downstream O/C relay = 0.55 sec
Allowing a grade margin of 250 msec,
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
Recommended Settings :
Current Setting = 110%
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
Multiples of plug setting current = = 12.35
60 x 1.00
Recommended Settings :
Current Setting = 1300%
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