Fault Location:
Service Voltage: 400
Generator No-Load Voltage: 420 +5% of the Service Voltage
Supply Cable Parameters:
Busbar Length: 15 mtr
Busbar CSA: 400 sqmm
No. of bars per Phase: 1
Transformer Impedance:
Transformer kVA: 1500 kVA
Transformer Impedance: 7.06 mΩ
Elements contributing to the Fault: X (mΩ) R (mΩ)
Transformer: (Reactance) 7.06 X trafo = Z trafo
Transformer: (Resistance) 1.41 R trafo = X trafo x 0.2
Circuit Breaker: 0.15
Busbar: (Reactance) 2.25 X cable = 0.15 x Length
Busbar: (Resistance) 0.86 R cable = (23mΩ x Length) / (Phase CSA)
Sum of the Fault Elements: X (mΩ) R (mΩ)
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 Isc = No Load Voltage / (sqrt (3) x Impedance)
Calculated value of k: 1.50
Short Circuit Fault Current (Peak): 52.76 kA Iscpk = Isc x k x sqrt (2)
Average Reactance per Metre of a Busbar = 0.15mΩ (Based on only 1No. Transformer feeding the Main Board)
Average Reactance for an MCB = 0.15mΩ From Generator to Main Distribution Board
For a 1500kVA Transformer: Usc = 6%
Conductor Resistivity per Metre (with an MCB) = 0.023Ω
Steady State Fault Current Isc
Peak Asymmetrical Fault Current Iscpk Volts
Volts
Calculation for Short Circuit Fault Current
At the Main Switchboard. PROJECT:- STEP ERC office
Fault Location:
Service Voltage: 400
Transformer No-Load Voltage: 420 +5% of the Service Voltage
Supply Cable Parameters:
Cable Length: 70 mtr
Cable CSA: 95 sqmm
No. of Cores per Phase: 1
Elements contributing to the Fault: X (mΩ) R (mΩ)
Circuit Breaker: 0.15
Cable: (Reactance) 5.6 X cable = 0.08 x Length
Cable: (Resistance) 16.95 R cable = (23mΩ x Length) / (Phase CSA)
Circuit Breaker: 0.15
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: X (mΩ) R (mΩ)
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 Isc = No Load Voltage / (sqrt (3) x Impedance)
Calculated value of k: 1.02
Short Circuit Fault Current (Peak): 19.50 kA Iscpk = Isc x k x sqrt (2)
Average Reactance for an MCB = 0.15mΩ
Conductor Resistivity per Metre (with an MCB) = 0.023Ω
Peak Asymmetrical Fault Current Iscpk Average Reactance for an MCB = 0.15mΩ
Steady State Fault Current Isc
Average Reactance per Metre of a 3 Phase Cable = 0.08mΩ From the Generator to Main Distribution Board
Volts
Calculation for Short Circuit Fault Current
Sub Main Distribution Board 0S-EDB82C01. PROJECT:- Camp Accommodation and Recreation
Volts
Fault Location:
Service Voltage: 400
Transformer No-Load Voltage: 420 +5% of the Service Voltage
Supply Cable Parameters:
Cable Length: 30 mtr
Cable CSA: 25 sqmm
No. of Cores per Phase: 1
Elements contributing to the Fault: X (mΩ) R (mΩ)
Circuit Breaker: 0.15
Cable: (Reactance) 2.4 X cable = 0.08 x Length
Cable: (Resistance) 27.60 R cable = (23mΩ x Length) / (Phase CSA)
Circuit Breaker: 0.15
Upstream Values at MDB 5.90 16.95 Refer to the S/C Calculation for 0S-EDB82C01
Sum of the Fault Elements: X (mΩ) R (mΩ)
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 Isc = No Load Voltage / (sqrt (3) x Impedance)
Calculated value of k: 1.02
Short Circuit Fault Current (Peak): 7.71 kA Iscpk = Isc x k x sqrt (2)
Distribution Board 0S-EDB82C10 in the Recreation Block.
Calculation for Short Circuit Fault Current
PROJECT:- STEP ERC Building
Volts Volts
Average Reactance for an MCB = 0.15mΩ
Peak Asymmetrical Fault Current Iscpk Steady State Fault Current Isc
Average Reactance per Metre of a 3 Phase Cable = 0.08mΩ Conductor Resistivity per Metre (with an MCB) = 0.023Ω From Main Distribution Board to DB1
Average Reactance for an MCB = 0.15mΩ
Fault Location:
Service Voltage: 400
Transformer No-Load Voltage: 420 +5% of the Service Voltage
Supply Cable Parameters:
Cable Length: 10 mtr
Cable CSA: 25 sqmm
No. of Cores per Phase: 1
Elements contributing to the Fault: X (mΩ) R (mΩ)
Circuit Breaker: 0.15
Cable: (Reactance) 0.8 X cable = 0.08 x Length
Cable: (Resistance) 9.20 R cable = (23mΩ x Length) / (Phase CSA)
Circuit Breaker: 0.15
Upstream Values at 0S-EDB82C10: 8.60 44.55 Refer to S/C Calculation for 0S-EDB82C10.
Sum of the Fault Elements: X (mΩ) R (mΩ)
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 Isc = No Load Voltage / (sqrt (3) x Impedance)
Calculated value of k: 1.02
Short Circuit Fault Current (Peak): 6.40 kA Iscpk = Isc x k x sqrt (2)
Distribution Board 0S-EDB82C11 in the Recreation Block.
Calculation for Short Circuit Fault Current
PROJECT:- Camp Accommodation and Recreation
Volts Volts
Average Reactance for an MCB = 0.15mΩ
Peak Asymmetrical Fault Current Iscpk Steady State Fault Current Isc
Average Reactance per Metre of a 3 Phase Cable = 0.08mΩ Conductor Resistivity per Metre (with an MCB) = 0.023Ω From 0S-EDB82C10 to 0S-EDB82C11.
Average Reactance for an MCB = 0.15mΩ
Fault Location:
Service Voltage: 400
Transformer No-Load Voltage: 420 +5% of the Service Voltage
Supply Cable Parameters:
Cable Length: 10 mtr
Cable CSA: 16 sqmm
No. of Cores per Phase: 1
Elements contributing to the Fault: X (mΩ) R (mΩ)
Circuit Breaker: 0.15
Cable: (Reactance) 0.8 X cable = 0.08 x Length
Cable: (Resistance) 14.38 R cable = (23mΩ x Length) / (Phase CSA)
Circuit Breaker: 0.15
Upstream Values at 0S-EDB82C10: 8.60 44.55 Refer to S/C Calculation for 0S-EDB82C10.
Sum of the Fault Elements: X (mΩ) R (mΩ)
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 Isc = No Load Voltage / (sqrt (3) x Impedance)
Calculated value of k: 1.02
Short Circuit Fault Current (Peak): 5.86 kA Iscpk = Isc x k x sqrt (2)
Conductor Resistivity per Metre (with an MCB) = 0.023Ω From 0S-EDB82C10 to 0S-EDB82C12.
Average Reactance for an MCB = 0.15mΩ
Steady State Fault Current Isc
Average Reactance per Metre of a 3 Phase Cable = 0.08mΩ Average Reactance for an MCB = 0.15mΩ
Peak Asymmetrical Fault Current Iscpk
Calculation for Short Circuit Fault Current
PROJECT:- Camp Accommodation and Recreation
Volts Volts
Distribution Board 0S-EDB82C12 in the Recreation Block.
