Question 2 A 13.8kV 100MW 125MVA generator having a positive-sequence impedance of j28.0% and a negative-sequence impedance of j22.4% is connected to a 13.8/275kV 125MVA delta/star step-up transformer having an impedance of j15.0%, the 275Kv neutral point of the latter being solidly earthed. Assuming a two-phase-to-earth fault at the 275kV terminals of the transformer, determine the values of the phase currents at the point of fault and the voltage to earth of the unfaulted phase at the point of fault. The pre-fault phase-to-phase voltage at the point of fault can be assumed to be equal to the rated value of 275kV. The 275kV circuit breaker is assumed to be open (i.e. there is no fault current infeed from the 275kV system) Figure 2. 100 MW 13.8 KV 125 MVA p 4-6-e FAULT 275 kV

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question 2 a 13 8kv 100mw 125mva generator having a positive sequence

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Question 2 A 13.8kV 100MW 125MVA generator having a positive-sequence impedance of j28.0% and a negative-sequence impedance of j22.4% is connected to a 13.8/275kV 125MVA delta/star step-up transformer having an impedance of j15.0%, the 275Kv neutral point of the latter being solidly earthed. Assuming a two-phase-to-ear