67988343 Sample Short Circuit Calculation
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File Name: file:///home/website/convert/temp/convert_html/55721200497959fc0b8fdd3c/document.xls Page: 1 of 5 Calculation Sheet Calculation for Short Circuit Fault Current PROJECT:- STEP ERC office Fault Location: At the Main Switchboard. Service Voltage: 400 Volts Generator No-Load Voltage: 420 Volts +5% of the Service Voltage Supply Cable Parameters: From Generator to Main Distribution Board Busbar Length: 15 mtr Busbar CSA: 400 sqmm No. of bars per Phase: 1 Transformer Impedance: Transformer kVA: 1500 kVA For a 1500kVA Transformer: Usc = 6% Transformer Impedance: 7.06 mΩ Elements contributing to the Fault: Transformer: (Reactance) 7.06 X trafo = Z trafo Transformer: (Resistance) 1.41 R trafo = X trafo x 0.2 Circuit Breaker: 0.15 Average Reactance for an MCB = 0.15mΩ Busbar: (Reactance) 2.25 Average Reactance per Metre of a Busbar = 0.15mΩ X cable = 0.15 x Length Busbar: (Resistance) 0.86 Conductor Resistivity per Metre (with an MCB) = 0.02 R cable = (23mΩ x Length) / (Phase CSA) Sum of the Fault Elements: Total Reactance: 9.46 Total Resistance: 2.27 Total Impedance: 9.726 mΩ Short Circuit Fault Currents: Short Circuit Fault Current (Steady State24.93 kA Steady State Fault Current Isc Isc = No Load Voltage / (sqrt (3) x Imped Calculated value of k: 1.50 Short Circuit Fault Current (Peak): 52.76 kA Peak Asymmetrical Fault Current Iscpk Iscpk = Isc x k x sqrt (2) (Based on only 1No. Transformer feeding the Main Board) X (mΩ) R (mΩ) X (mΩ) R (mΩ)
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Transcript of 67988343 Sample Short Circuit Calculation
File Name: file:///tt/file_convert/55721200497959fc0b8fdd3c/document.xls Page: 1 of 5
Calculation Sheet
Calculation for Short Circuit Fault Current
PROJECT:- STEP ERC office
Fault Location: At the Main Switchboard.
Service Voltage: 400 Volts
Generator No-Load Voltage: 420 Volts +5% of the Service Voltage
Supply Cable Parameters: From Generator to Main Distribution Board
Busbar Length: 15 mtr
Busbar CSA: 400 sqmm
No. of bars per Phase: 1
Transformer Impedance:
Transformer kVA: 1500 kVA For a 1500kVA Transformer: Usc = 6%
Transformer Impedance: 7.06 mΩ (Based on only 1No. Transformer feeding the Main Board)
Elements contributing to the Fault:
Transformer: (Reactance) 7.06 X trafo = Z trafo
Transformer: (Resistance) 1.41 R trafo = X trafo x 0.2
Circuit Breaker: 0.15 Average Reactance for an MCB = 0.15mΩ
Busbar: (Reactance) 2.25 Average Reactance per Metre of a Busbar = 0.15mΩ X cable = 0.15 x Length
Busbar: (Resistance) 0.86 Conductor Resistivity per Metre (with an MCB) = 0.023Ω R cable = (23mΩ x Length) / (Phase CSA)
Sum of the Fault Elements:
Total Reactance: 9.46
Total Resistance: 2.27
Total Impedance: 9.726 mΩ
Short Circuit Fault Currents:
Short Circuit Fault Current (Steady State): 24.93 kA Steady State Fault Current Isc Isc = No Load Voltage / (sqrt (3) x Impedance)
Calculated value of k: 1.50
Short Circuit Fault Current (Peak): 52.76 kA Peak Asymmetrical Fault Current Iscpk Iscpk = Isc x k x sqrt (2)
X (mΩ) R (mΩ)
X (mΩ) R (mΩ)
File Name: file:///tt/file_convert/55721200497959fc0b8fdd3c/document.xls Page: 2 of 5
Calculation Sheet
Calculation for Short Circuit Fault Current
PROJECT:- Camp Accommodation and Recreation
Fault Location: Sub Main Distribution Board 0S-EDB82C01.
Service Voltage: 400 Volts
Transformer No-Load Voltage: 420 Volts +5% of the Service Voltage
Supply Cable Parameters: From the Generator to Main Distribution Board
Cable Length: 70 mtr
Cable CSA: 95 sqmm
No. of Cores per Phase: 1
Elements contributing to the Fault:
Circuit Breaker: 0.15 Average Reactance for an MCB = 0.15mΩ
Cable: (Reactance) 5.6 Average Reactance per Metre of a 3 Phase Cable = 0.08mΩ X cable = 0.08 x Length
Cable: (Resistance) 16.95 Conductor Resistivity per Metre (with an MCB) = 0.023Ω R cable = (23mΩ x Length) / (Phase CSA)
Circuit Breaker: 0.15 Average Reactance for an MCB = 0.15mΩ
Upstream Values at the Main SWB: 0.00 0.00 Refer to the S/C Calculation for the Main SWB
Sum of the Fault Elements:
Total Reactance: 5.90
Total Resistance: 16.95
Total Impedance: 17.945 mΩ
Short Circuit Fault Currents:
Short Circuit Fault Current (Steady State): 13.51 kA Steady State Fault Current Isc Isc = No Load Voltage / (sqrt (3) x Impedance)
Calculated value of k: 1.02
Short Circuit Fault Current (Peak): 19.50 kA Peak Asymmetrical Fault Current Iscpk Iscpk = Isc x k x sqrt (2)
X (mΩ) R (mΩ)
X (mΩ) R (mΩ)
File Name: file:///tt/file_convert/55721200497959fc0b8fdd3c/document.xls Page: 3 of 5
Calculation Sheet
Calculation for Short Circuit Fault Current
PROJECT:- STEP ERC Building
Fault Location: Distribution Board 0S-EDB82C10 in the Recreation Block.
Service Voltage: 400 Volts
Transformer No-Load Voltage: 420 Volts +5% of the Service Voltage
Supply Cable Parameters: From Main Distribution Board to DB1
Cable Length: 30 mtr
Cable CSA: 25 sqmm
No. of Cores per Phase: 1
Elements contributing to the Fault:
Circuit Breaker: 0.15 Average Reactance for an MCB = 0.15mΩ
Cable: (Reactance) 2.4 Average Reactance per Metre of a 3 Phase Cable = 0.08mΩ X cable = 0.08 x Length
Cable: (Resistance) 27.60 Conductor Resistivity per Metre (with an MCB) = 0.023Ω R cable = (23mΩ x Length) / (Phase CSA)
Circuit Breaker: 0.15 Average Reactance for an MCB = 0.15mΩ
Upstream Values at MDB 5.90 16.95 Refer to the S/C Calculation for 0S-EDB82C01
Sum of the Fault Elements:
Total Reactance: 8.60
Total Resistance: 44.55
Total Impedance: 45.370 mΩ
Short Circuit Fault Currents:
Short Circuit Fault Current (Steady State): 5.34 kA Steady State Fault Current Isc Isc = No Load Voltage / (sqrt (3) x Impedance)
Calculated value of k: 1.02
Short Circuit Fault Current (Peak): 7.71 kA Peak Asymmetrical Fault Current Iscpk Iscpk = Isc x k x sqrt (2)
X (mΩ) R (mΩ)
X (mΩ) R (mΩ)
File Name: file:///tt/file_convert/55721200497959fc0b8fdd3c/document.xls Page: 4 of 5
Calculation Sheet
Calculation for Short Circuit Fault Current
PROJECT:- Camp Accommodation and Recreation
Fault Location: Distribution Board 0S-EDB82C11 in the Recreation Block.
Service Voltage: 400 Volts
Transformer No-Load Voltage: 420 Volts +5% of the Service Voltage
Supply Cable Parameters: From 0S-EDB82C10 to 0S-EDB82C11.
Cable Length: 10 mtr
Cable CSA: 25 sqmm
No. of Cores per Phase: 1
Elements contributing to the Fault:
Circuit Breaker: 0.15 Average Reactance for an MCB = 0.15mΩ
Cable: (Reactance) 0.8 Average Reactance per Metre of a 3 Phase Cable = 0.08mΩ X cable = 0.08 x Length
Cable: (Resistance) 9.20 Conductor Resistivity per Metre (with an MCB) = 0.023Ω R cable = (23mΩ x Length) / (Phase CSA)
Circuit Breaker: 0.15 Average Reactance for an MCB = 0.15mΩ
Upstream Values at 0S-EDB82C10: 8.60 44.55 Refer to S/C Calculation for 0S-EDB82C10.
Sum of the Fault Elements:
Total Reactance: 9.70
Total Resistance: 53.75
Total Impedance: 54.616 mΩ
Short Circuit Fault Currents:
Short Circuit Fault Current (Steady State): 4.44 kA Steady State Fault Current Isc Isc = No Load Voltage / (sqrt (3) x Impedance)
Calculated value of k: 1.02
Short Circuit Fault Current (Peak): 6.40 kA Peak Asymmetrical Fault Current Iscpk Iscpk = Isc x k x sqrt (2)
X (mΩ) R (mΩ)
X (mΩ) R (mΩ)
File Name: file:///tt/file_convert/55721200497959fc0b8fdd3c/document.xls Page: 5 of 5
Calculation Sheet
Calculation for Short Circuit Fault Current
PROJECT:- Camp Accommodation and Recreation
Fault Location: Distribution Board 0S-EDB82C12 in the Recreation Block.
Service Voltage: 400 Volts
Transformer No-Load Voltage: 420 Volts +5% of the Service Voltage
Supply Cable Parameters: From 0S-EDB82C10 to 0S-EDB82C12.
Cable Length: 10 mtr
Cable CSA: 16 sqmm
No. of Cores per Phase: 1
Elements contributing to the Fault:
Circuit Breaker: 0.15 Average Reactance for an MCB = 0.15mΩ
Cable: (Reactance) 0.8 Average Reactance per Metre of a 3 Phase Cable = 0.08mΩ X cable = 0.08 x Length
Cable: (Resistance) 14.38 Conductor Resistivity per Metre (with an MCB) = 0.023Ω R cable = (23mΩ x Length) / (Phase CSA)
Circuit Breaker: 0.15 Average Reactance for an MCB = 0.15mΩ
Upstream Values at 0S-EDB82C10: 8.60 44.55 Refer to S/C Calculation for 0S-EDB82C10.
Sum of the Fault Elements:
Total Reactance: 9.70
Total Resistance: 58.92
Total Impedance: 59.715 mΩ
Short Circuit Fault Currents:
Short Circuit Fault Current (Steady State): 4.06 kA Steady State Fault Current Isc Isc = No Load Voltage / (sqrt (3) x Impedance)
Calculated value of k: 1.02
Short Circuit Fault Current (Peak): 5.86 kA Peak Asymmetrical Fault Current Iscpk Iscpk = Isc x k x sqrt (2)
X (mΩ) R (mΩ)
X (mΩ) R (mΩ)
