Transformer Capacity 13.5 MVA
Primary Voltage (HT) 132 KV
Secondary Voltage(LT) 27 KV
Rated Primary Current (Ip) 102.27 Amp
Rated Secondary Current (Is) 500.00 Amp
Max.Earth Fault Current at HV Side (L-G) 1100 Amp Min.Earth Fault Current at HV Side (L-G) 1000 Amp Max.Earth Fault Current at LV Side (LG) 900 Amp Min.Earth Fault Current at LV Side (L-G) 800 Amp Max.Earth Fault Current at Downstrem of TC (L-G) 700 Amp Min.Earth Fault Current at Downstrem of TC (L-G) 600 Amp
Max.Fault Current at HV Side (L-L) 5000 Amp
Min.Fault Current at HV Side (L-L) 5500 Amp
Max.Fault Current at LV Side (L-L) 4500 Amp
Min.Fault Current at LV Side (L-L) 4000 Amp
Max.Fault Current at Downstrem Side of TC (L-L) 3500 Amp Min.Fault Current at Downstrem Side of TC (L-L) 3000 Amp
CT for O/C & Earth Fault Protection:
CT Ratio (LT Side)
Prim. Current (Amp) 500
Sec. Current (Amp) 5
CT Ratio (HT Side)
Prim. Current (Amp) 100
Sec. Current (Amp) 5
CT for Differential Protection:
CT Ratio (LT Side)
Prim. Current (Amp) 1000
Sec. Current (Amp) 5.11
CT Ratio (HT Side)
Prim. Current (Amp) 200
Sec. Current (Amp) 5
IDMT Over Current Relay Setting LV Side
Plug Setting of Over Current Relay (I>) 1.25 A X In Actual Operaion Time of Relay: (t>) 0.348 Sec Plug Setting of Over Current Relay (I>>) 1.5 A X In Actual Operaion Time of Relay: (t>>) 0.498 Sec Plug Setting of Over Current Relay (I>>>) 1.4 A X In Actual Operaion Time of Relay: (t>>>) 0.428 Sec
HV Side
Plug Setting of Over Current Relay (I>) 1.28 A X In Actual Operaion Time of Relay: (t>) 0.184 Sec Plug Setting of Over Current Relay (I>>) 1.6 A X In Actual Operaion Time of Relay: (t>>) 0.211 Sec Plug Setting of Over Current Relay (I>>>) 1.5 A X In Actual Operaion Time of Relay: (t>>>) 0.199 Sec
IDMT Earth Fault Relay Setting
:Results of IDMT Relay Settings:
IDMT Relay Setting for Transformer (Over Current / Earth Fault / Differential) Protection
LV Side
Plug Setting of Earth Fault Relay (Ie>) 0.25 A X In Actual Operaion Time of Relay: (te>) 0.348 Plug Setting of Earth Fault Relay (Ie>>) 0.25 A X In Actual Operaion Time of Relay: (te>>) 0.439 Plug Setting of Earth Fault Relay (Ie>>>) 0.25 A X In Actual Operaion Time of Relay: (te>>>) 0.399
HV Side
Plug Setting of Earth Fault Relay (Ie>) 0.25 A X In Actual Operaion Time of Relay: (te>) 0.178 Sec Plug Setting of Earth Fault Relay (Ie>>) 0.25 A X In Actual Operaion Time of Relay: (te>>) 0.195 Sec Plug Setting of Earth Fault Relay (Ie>>>) 0.25 A X In Actual Operaion Time of Relay: (te>>>) 0.188 Sec
Main Protection
Over Load Current : 125% X Is
Over Load Current :(In) 625 Amp
Required Over Current Relay Plug Setting 1.25 1.25 A X In Actual Plug Setting of Over Current Relay (I>) 125% 1.25 A X In Pick Up Setting of Over Current Relay (PMS): (I>) 6.25 Amp
Fault Current At CT Secondary Side 45 Amp
Plug Setting Multiplier (PSM): 7.2 Amp
Curve Selection:
Time Dial Setting of Over current Relay(TMS): 0.1 Sec
Time of Operation of Relay 3.476 Sec
Actual Operaion Time of Relay: (t>) 0.348 Sec
Back Up Protection for Down Stream
Actual Plug Setting of Over Current Relay (I>>) 150% 1.5 A X In Pick Up Setting of Over Current Relay (PMS): (I>>) 7.5 Amp
Fault Current At CT Secondary Side 30 Amp
Plug Setting Multiplier (PSM): 4 Amp
Curve Selection:
Time Dial Setting of Over current Relay(TMS): 0.1 Sec
Time of Operation of Relay 4.980 Sec
Actual Operaion Time of Relay: (t>>) 0.498 Sec Actual Plug Setting of Over Current Relay (I>>>) 140% 1.4 A X In Pick Up Setting of Over Current Relay (PMS): (I>>>) 7 Amp
Fault Current At CT Secondary Side 35 Amp
Plug Setting Multiplier (PSM): 5.000 Amp
Curve Selection:
Time Dial Setting of Over current Relay(TMS): 0.1 Sec
Time of Operation of Relay 4.280 Sec
Actual Operaion Time of Relay: (t>>>) 0.428 Sec
Over Load Current : 125% X Ip
Over Load Current :(In) 128 Amp
Required Over Current Relay Plug Setting 1.28 1.28 A X In Actual Plug Setting of Over Current Relay (I>) 128% 1.28 A X In Pick Up Setting of Over Current Relay (PMS): (I>) 6.4 Amp
Fault Current At CT Secondary Side 250 Amp
Plug Setting Multiplier (PSM): 39.06 Amp
Curve Selection:
Time Dial Setting of Over current Relay(TMS): 0.1 Sec
Time of Operation of Relay 1.841 Sec
Actual Operaion Time of Relay: (t>) 0.184 Sec
Back Up Protection for Down Stream
Actual Plug Setting of Over Current Relay (I>>) 160% 1.6 A X In Pick Up Setting of Over Current Relay (PMS): (I>>) 8 Amp
Fault Current At CT Secondary Side 200 Amp
Plug Setting Multiplier (PSM): 25.000 Amp
Curve Selection:
Jignesh.parmar,www.electricalnotes.wordpress.com,[email protected]
HT Side
Normal Inverse (NI)
Normal Inverse (NI)
IDMT Relay Setting for Transformer (Over Current / Earth Fault / Differential) Protection
LT Side
Normal Inverse (NI)
Normal Inverse (NI)
IDMT Over Current Relay Setting (50/51)
Time Dial Setting of Over current Relay(TMS): 0.1 Sec
Time of Operation of Relay 2.105
Actual Operaion Time of Relay: (t>>) 0.211 Sec Actual Plug Setting of Over Current Relay (I>>>) 150% 1.5 A X In Pick Up Setting of Over Current Relay (PMS): (I>>>) 7.5 Amp
Fault Current At CT Secondary Side 225 Amp
Plug Setting Multiplier (PSM): 30.000 Amp
Curve Selection:
Time Dial Setting of Over current Relay(TMS): 0.1 Sec
Time of Operation of Relay 1.989 Sec
Actual Operaion Time of Relay: (t>>>) 0.199 Sec
3500
35 700
56
Main Protection
Earth Fault Current : 20% X In
Earth Fault Current :(Inf) 125 Amp
Required Earth Fault Relay Plug Setting 0.25 0.25 A X In
Actual Plug Setting of Earth Fault Relay (Ie>) 25% 0.25 A X In Pick Up Setting of Earth Fault Relay (PMS): (Ie>) 1.25 Amp
Fault Current At CT Secondary Side 9 Amp
Plug Setting Multiplier (PSM): 7.2 Amp
Curve Selection:
Time Dial Setting of Earth Fault Relay(TMS): 0.1 Sec
Time of Operation of Relay 3.476 Sec
Actual Operaion Time of Relay: (te>) 0.348 Sec
Back Up Protection for Down Stream
Actual Plug Setting of Earth Fault Relay (Ie>>) 25% 0.25 A X In Pick Up Setting of Over Current Relay (PMS): (Ie>>) 1.25 Amp
Fault Current At CT Secondary Side 6 Amp
Plug Setting Multiplier (PSM): 4.8 Amp
Curve Selection:
Time Dial Setting of Earth Fault Relay(TMS): 0.1 Sec
Time of Operation of Relay 4.393 Sec
Actual Operaion Time of Relay: (te>>) 0.439 Sec Actual Plug Setting of Earth Fault Relay (Ie>>>) 25% 0.25 A X In Pick Up Setting of Earth Fault Relay (PMS): (Ie>>>) 1.25 Amp
Fault Current At CT Secondary Side 7 Amp
Plug Setting Multiplier (PSM): 5.600 Amp
Curve Selection:
Time Dial Setting of Earth Fault Relay(TMS): 0.1 Sec
Time of Operation of Relay 3.994 Sec
Actual Operaion Time of Relay: (te>>>) 0.399 Sec
Earth Fault Current : 20% X In
Earth Fault Current :(Inf) 26 Amp
Required Earth Fault Relay Plug Setting 0.26 0.26 A X In
Actual Plug Setting of Earth Fault Relay (Ie>) 25% 0.25 A X In Pick Up Setting of Over Current Relay (PMS): (Ie>) 1.25 Amp
Fault Current At CT Secondary Side 55 Amp
Plug Setting Multiplier (PSM): 44.00 Amp
Curve Selection:
Time Dial Setting of Earth Fault Relay(TMS): 0.1 Sec
Time of Operation of Relay 1.781 Sec
Actual Operaion Time of Relay: (te>) 0.178 Sec
Back Up Protection for Down Stream
Actual Plug Setting of Earth Fault Relay (Ie>>) 25% 0.25 A X In Pick Up Setting of Over Current Relay (PMS): (Ie>>) 1.25 Amp
Fault Current At CT Secondary Side 40 Amp
Plug Setting Multiplier (PSM): 32.000 Amp
Curve Selection:
Jignesh.parmar,www.electricalnotes.wordpress.com,[email protected]
HT Side
Normal Inverse (NI)
Normal Inverse (NI)
IDMT Earth Fault Relay Setting (50N/51N)
LT Side
Normal Inverse (NI)
Normal Inverse (NI)
Time Dial Setting of Over current Relay(TMS): 0.1 Sec
Time of Operation of Relay 1.951
Actual Operaion Time of Relay: (te>>) 0.195 Sec Actual Plug Setting of Earth Fault Relay (Ie>>>) 25% 0.25 A X In Pick Up Setting of Earth Fault Relay (PMS): (Ie>>>) 1.25 Amp
Fault Current At CT Secondary Side 45 Amp
Plug Setting Multiplier (PSM): 36.000 Amp
Curve Selection:
Time Dial Setting of Earth Fault Relay(TMS): 0.1 Sec
Time of Operation of Relay 1.884 Sec
Actual Operaion Time of Relay: (te>>>) 0.188 Sec Normal Inverse (NI)
Normal Tap 100% LT Side
Full Load Current 500.0 Amp
Current in Sec. Side of CT 2.555 Amp
HT Side
Full Load Current 102.27 Amp
Current in Sec. Side of CT 2.557 Amp
Spil Over current in Relay 0.002 Amp
Percentage Differntial Current 0.1 %
Highest Tap (+) 10%
Transformation Primary Voltage at + 10% 145.20 KV Transformation SecondaryVoltage at + 10% 27 KV LT Side
Full Load Current 500.0 Amp
Current in Sec. Side of CT 2.56 Amp
HT Side
Full Load Current 93.0 Amp
Current in Sec. Side of CT 2.32 Amp
Spil Over current in Relay 0.231 Amp
Percentage Differntial Current 9.5 %
Highest Tap (-) 15%
Transformation Primary Voltage at - 15% 112.20 KV Transformation Secondary Voltage at - 15% 27 KV LT Side
Full Load Current 500.0 Amp
Current in Sec. Side of CT 2.56 Amp
HT Side
Full Load Current 120.321 Amp
Current in Sec. Side of CT 3.01 Amp
Spil Over current in Relay 0.45 Amp
Percentage Differntial Current 16.3 %
Normal Inverse (NI) Very Inverse (VI) Exteremely Inverse (EI) Long Inverse