9.1 Assume for this problem that the 69 kV system (Figure P9.1) is open and make...

 

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9.1 Assume for this problem that the 69 kV system (Figure P9.1) is open and make the following calculations: a. Calculate the fault current in the three phases for a solid phase-a-to-ground fault on the 69 kV terminals. b. Calculate the three-phase voltages existing at the fault. c. For this 69 kV ground fault, determine the currents flowing in the 13.8 kV system. Source 50 MVA mm www 13.8 kV B F 13.8 kV X X2 12 % 50 MVA 13.8:69 kV X=8% 69 kV a tuw tuw 9.1 Assume for this problem that the 69 kV system (Figure P9.1) is open and make the following calculations: a. Calculate the fault current in the three phases for a solid phase-a-to-ground fault on the 69 kV terminals. b. Calculate the three-phase voltages existing at the fault. c. For this 69 kV ground fault, determine the currents flowing in the 13.8 kV system. Source 50 MVA mm www 13.8 kV B F 13.8 kV X X2 12 % 50 MVA 13.8:69 kV X=8% 69 kV a tuw tuw