Electrical Engineering: Power system MCQ

Getting Started with Electrical Engineering: Power system MCQ: 

1. Question

The single line diagram of a balanced power system is shown in the figure. The voltage magnitude at the generator internal bus is constant and 1.0 p.u. The p.u. reactances of different components in the system are also shown in the figure. The infinite bus voltage magnitude is 1.0 p.u. A three phase fault occurs at the middle of line 2.

The ratio of the maximum real power that can be transferred during the pre-fault condition to the maximum real power that can be transferred under the faulted condition is _________.

2. Question

At no load condition, a 3-phase, 50 Hz, lossless power transmission line has sending-end and receiving-end voltages of 400 kV and 420 kV respectively. Assuming the velocity of traveling wave to be the velocity of light, the length of the line, in km, is ____________.

3. Question

Two identical unloaded generators are connected in parallel as shown in the figure. Both the generators are having positive, negative and zero sequence impedances of j0.4 p.u., j0.3 p.u. and j0.15 p.u., respectively. If the pre-fault voltage is 1 p.u., for a line-to-ground (L-G) fault at the terminals of the generators, the fault current, in p.u., is ___________.

4. Question

Base load power plants are
P. wind farms
Q. run-of-river plants
R. nuclear power plants
S. diesel power plants

5. Question

Consider the economic dispatch problem for a power plant having two generating units. The fuel costs in Rs/MWh along with the generation limits for the two units are given below:

C1 (P1 ) = 0.01 P12 + 30P1 + 10 ; 100 MW ≤ P1 ≤ 150 MW

C2 (P2 ) = 0.05 P22 + 10P2 + 10 ; 100 MW ≤ P2 ≤ 180 MW

The incremental cost (in Rs/MWh) of the power plant when it supplies 200 MW is __________.