The single line diagram of figure below shows a generator connected through parallel transmission line to a large metropolitan system considered as an infinite bus. The machine is delivering 1.0 per-unit power and both the terminal voltage and the infinite-bus voltage are 1.0 per unit. Numbers of the diagram indicate the values of the reactances on a common system base. The transient reactance of the generator is 0.2x per unit as indicated. Determine the power-angle equation for the given system operating conditions. When a three-phase fault occurs at point P, and the fault on the system is cleared by simultaneous opening of the circuit breakers at each end of the affected line, determine the power angle equation and the swing equation for the during fault and post-fault period. Take H= 5.5Q Mj/MVA. (Roll=PQXY)

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

2.2. The figure below shows a radial transmission system with a generator having a per-unit voltage of 1.3 at an angle of 9 degree p.u. The load demand is 47MW at a power factor of 0.96lagging. Use the nameplate values of Transformer 2 as base values and calculate the following: Correct answers to three decimal places :   25..Per unit impedance of transformer and it's angle 26.Per unit voltage of the line and its angle 27.Per unit impedance of the line and its angle. And Reactance of the transmission line when the load consumes full-load (Ω).

By comparing the principle of operation of a "three" phase generation system with a single-phase system, state what are the bendfits of three phase systems? In your own words, define the "skin effect" in transmission lines and discuss how can it be minimised? Name three advantages of AC transmission in comparison to DC transmission. What are the units of active, reactive and apparent power? The current in a single-phase motor lags 50° behind the voltage. What is the power factor of the motor?