In a transmission line each conductor is at $$20$$ $$kV$$ and is supported by a string of $$3$$ suspension insulators. The air capacitance between each cap-pin junction and tower is one-fifth of the capacitance $$C$$ of each insulation unit. A guard ring, effective only over the line-end insulator unit is fitted so that the voltages on the two units nearest the line-end are equal.

(a) Calculate the voltage on the line-end unit.
(b) Calculate the value of capacitance $${C_x}$$ required.

Incremental fuel costs (in some appropriate unit) for a power plant consisting of three generating units are
$${\rm I}{C_1} = 20 + 0.3\,\,{P_1},\,{\rm I}{C_2} = 30 + 0.4\,\,{P_2},\,{\rm I}{C_3} = 30$$
Assume that all the three units are operating all the time. Minimum and maximum loads on each unit are $$50$$ $$MW$$ and $$300$$ $$MW$$ respectively. If the plant is operating on economic load dispatch to supply the total power demand of $$700$$ $$MW$$, the power generated by each unit is

A round rotor generator with internal voltage $${E_1} = 2.0\,\,$$ p.u.and $$\,X = 1.1\,\,$$ p.u. is connected to a round rotor synchronous motor with internal voltage $$\,\,{E_2} = 1.3\,\,$$ p.u. and $$\,X = 1.2\,\,$$ p.u. The reactance of the line connecting the generator to the motor is $$0.5$$ p.u. when the generator supplies $$0.5$$ p.u. power, the rotor angle difference between the machines will be

A generator delivers power of 1.0 p.u. to an infinite bus through a purely reactive network. The maximum power that could be delivered by the generator is 2.0 p.u. A three-phase fault occurs at the terminals of the generator which reduces the generator output to zero. The fault is cleared after $${t_c}$$ seconds. The original network is then restored. The maximum swing of the rotor angle is found to be $${\delta _{\max }} = 110$$ electrical degree. Then the rotor angle in electrical degrees at $$t = {t_c}$$ is