Your Answer : (Not Answered)

Correct Answer : D

Both Statement I and Statement II are true.

Statement I is true: India's grid was planned and is still operated as regional grids: Northern, Western, Eastern, North-Eastern and Southern. Each has its own Regional Load Despatch Centre under the national centre, even though they are now synchronised as one national grid.

Statement II is true: peak demand in one region often falls at a different time from another region's, or when another region has surplus generation. Inter-regional links let peak demand be met by power transferred from generating systems in other parts of the country, which is a main reason for interconnecting the grids.

Your Answer : (Not Answered)

Correct Answer : A

The correct matching is (a)-(i), (b)-(iii), (c)-(iv), (d)-(ii).

• The exciter supplies the field current of the alternator, so it controls the terminal voltage (and reactive power): (i).
• The governor controls the prime mover's input, and so the active power output and frequency: (iii).
• A lightning arrester diverts surge overvoltages to earth: (iv).
• A circuit breaker interrupts overcurrents and fault currents when its relay trips it: (ii).

The other options give the governor voltage control or the circuit breaker overvoltage duty, which are the jobs of the exciter and the arrester.

Your Answer : (Not Answered)

Correct Answer : D

The optimal sharing is P₁ = 30 MW and P₂ = 10 MW.

Neglecting losses, the load is shared most economically when both plants run at the same incremental cost, with \(P_{1} + P_{2} = 40\).

\[ \begin{aligned} 0.2P_{1} + 5 &= 0.1P_{2} + 10 \\ 0.2P_{1} + 5 &= 0.1(40 - P_{1}) + 10 \\ 0.3P_{1} &= 9 \\ P_{1} &= 30,\ P_{2} = 10 \end{aligned} \]

Check: \(IC_{1} = 0.2(30) + 5 = 11\) and \(IC_{2} = 0.1(10) + 10 = 11\) Rs/MWh, equal as required. Any other split leaves the incremental costs unequal; for example 10 and 30 MW gives 7 and 13 Rs/MWh, so shifting load to plant 1 would cut the total cost.