Question

The synchronous generator shown in the figure is supplying active power to an infinite bus via two short lossless transmission lines, and is initially in steady state. The mechanical power input to the generator and the voltage magnitude E are constant. If one line is tripped at time
$t_1$ by opening the circuit breakers at the two ends (although there is no fault), then it is seen that the generator undergoes a stable transient. Which one of the following waveforms of the rotor angle $\delta$ shows the transient correctly?

• A.
• B.
• C.
• D.

Answer 1

The correct option is A

Initial value of $\delta ={\delta }_0$ at $t=t_1$ with both lines are in service. If one of the line circuit breakers is opened then $\delta$ is increased for some time and stabilizes to new value of $\delta$.