Power Systems Multiple Choice Questions on “Inductance of Composite Conductor Lines – 1”.
1. The per unit value of any quantity is usually given by _____________
A. (The actual value in any units)/(The base base value in same in same units)
B. (The base base value in same in same units)/(The actual value in any units)
C. The actual value in any units* The actual value in any units
D. 1/(The base base value)
Answer: A
Clarification: The per unit value is given as (The actual value in any units)/(The base base value in same in same units).
2. If Xa is the armature reactance of a synchronous machine and Xl is the leakage reactance of the same machine, then the synchronous reactance is ____________
A. Xa+Xl
B. ½(Xa)
C. 1/2(Xa+Xl)
D. None of the mentioned
Answer: A
Clarification: Xs = Xa+Xl
3. A large bus system whose voltage and frequency remain constant independent of the power exchange between the synchronous machine and the bus is called ________________
A. infinite bus
B. load bus
C. generator bus
D. cannot be determined
Answer: A
Clarification: It is infinite bus.
4. In a three phase system the three-phase fault MVA is always higher than the LG fault MVA at a bus.
A. True
B. False
Answer: A
Clarification: Yes, at the bus three phase system the three-phase fault MVA is always higher than the LG fault.
5. The charging current of a 400 kV is _____ that of 220 kV line of the same length.
A. more than
B. less than
C. equal to
D. none of the mentioned
Answer: A
Clarification: Line charging current is proportional to voltage.
6. Voltage regulation in the power system is __________
A. rise in voltage at receiving end
B. dip in voltage at receiving end
C. rise in voltage at sending end
D. dip in voltage at sending end
Answer: A
Clarification: VR is rise in voltage at receiving end for a transmission line.
7. Voltage regulation becomes negative for a ______load.
A. leading
B. lagging
C. zero power factor
D. unity power factor
Answer: A
Clarification: VR will be negative for a leading load at a receiving end.