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A generator feeds power to an infinite bus through a double circuit transmission line. A3 phase fault occurs at the middle point of one of the lines. The infinite bus voltage is 1 pu, the transient internal voltage of the generator is 1.1 pu and the equivalent transfer admittance during fault is 0.8 pu. The 100 MVA generator has an inertia constant of 5MJ/MVA and it was delivering 1.0 pu power prior of the fault with rotor power angle of 30 °. The system frequency is 50 Hz. The initial accelerating power (in pu) will be

A 600 KVA generator with X"a = 0.22 per unit is connected to a bus through a circuit breaker, as shown in the following figure. Connected through circuit breakers to the same bus are three synchronous motors rated 200 KVA, 2.5 KV, 1.0 power factor, with X"a = 0.15 per unit. The motors are operating at full load, unity power factor and rated voltage, with the load equally divided among the machines. (a) Find the rated symmetrical short-circuit current in Amperes, which must be interrupting breakers A and B for a fault at point P. Simplify the calculations by neglecting the Prefault current. M. GHA B

H.W Q1) A four pole, three-phase synchronous generator is rated 250 MVA, its terminal voltage is 24 kV, the synchronous reactance is: 125%. ERI • Calculate the synchronous reactance in ohm. Calculate the rated current and the line to ground terminal voltage. Draw the equivalent circuit. • Calculate the induced voltage, E., at rated load and pf = 0.8 lag.