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Pleas eshow all work: Link to image: http://i.imgur.com/HBf1nJU.png A portion of

ID: 1813324 • Letter: P

Question

Pleas eshow all work:


Link to image: http://i.imgur.com/HBf1nJU.png



A portion of a 13.8-kV radial system is shown below. The system may be operated with only one rather than two source transformers. Assume the high-voltage bus of the transformer is an infinite bus. The protection system for three-phase faults is to be designed. Transmission line reactances in ohms are shown in the figure. The transformer reactances in ohms are referred to the 13.8-kV side. Calculate the maximum and minimum fault currents for a fault at bus

Explanation / Answer

Maximum Fault Current = 203 Ampere

Minimum Fault Current = 165 Ampere


since miximum fault current ll occur for three phase when both the transformer operates...

whereas

minimum fault current is taken for line to line fault