A generator-transformer unit is connected to a line through a circuit breaker. The unit ratings are...

 

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A generator-transformer unit is connected to a line through a circuit breaker. The unit ratings are as shown in Table Q 1. Unit Generator Transformer Table Q 1 Parameter Ratings 10MVA,6.6KV,X = 0.8p. u, X = 0.2p. u X 10MVA, 6.6/33KV, Reactance 0.08p.u The system is operating no load at a line voltage of 30KV, when a three phase fault occurs on the line just beyond the circuit breaker. Find the following: a) Initial symmetrical rms current in the breaker b) Maximum possible DC off-set current in the breaker c) Momentary current rating of the breaker d) Current to be interrupted by the breaker and the interrupting kVA e) Sustained short circuit current in the breaker A generator-transformer unit is connected to a line through a circuit breaker. The unit ratings are as shown in Table Q 1. Unit Generator Transformer Table Q 1 Parameter Ratings 10MVA,6.6KV,X = 0.8p. u, X = 0.2p. u X 10MVA, 6.6/33KV, Reactance 0.08p.u The system is operating no load at a line voltage of 30KV, when a three phase fault occurs on the line just beyond the circuit breaker. Find the following: a) Initial symmetrical rms current in the breaker b) Maximum possible DC off-set current in the breaker c) Momentary current rating of the breaker d) Current to be interrupted by the breaker and the interrupting kVA e) Sustained short circuit current in the breaker