A $$275$$ $$kV,$$ $$3$$-phase, $$50$$ $$Hz,$$ $$400$$ $$km$$ lossless line has following parameters:
$$x=0.05$$ $$ohms/km,$$ line charging susceptance $$y=3.0$$ micro-Siemens/k.

(a) Calculate the receiving end voltage on open circuit using justifiable assumptions.

(b) What load at the receiving end will result in a flat voltage profile on the line?

(c) If the flat voltage profile is to be achieved at $$1.2$$ times the loading in (b), what will be the nature and quantum of uniformly distributed compensation required?

For the configuration shown in figure, the breaker connecting a large system to bus $$2$$ is initially open. The system $$3$$-phase fault level at bus $$3$$ under this condition is not known. After closing the system breaker, the $$3$$-phase fault level at bus $$1$$ was found to be $$5.0$$ p.u. What will be the new $$3$$-phase fault level at system bus $$3,$$ after the interconnection? All per unit values are on common base. Prefault load currents are neglected and prefault voltages are assumed to be $$1.0$$ p.u. at all buses.

In a 3-step distance protection, the reach of the three zones of the relay at the beginning of the first line typically extends upto

The plug setting of a negative sequence relay is $$0.2$$ $$A.$$ The current transformer ratio is $$5:1$$. The minimum value of line to line fault current for the operation of the relay is