### MCQs of Basic Principles

Showing 51 to 60 out of 135 Questions
51.
In a power system, the 3-phase fault MVA is always higher than L-G fault MAV at bus
 (a) True (b) False (c) Insufficient data
52.
If the transformer winding resistances and reactances are expressed in pu value, then
 (a) R1(pu)=R2(pu) and X1(pu)≠X2(pu) (b) R1(pu)≠R2(pu) and X1(pu)=X2(pu) (c) R1(pu)=0.5R2(pu) and X1(pu)=0.5X2(pu) (d) R1(pu)=R2(pu) and X1(pu)=X2(pu)
53.
If Xa is the armature reactance of a synchronous machine and Xl is the leakage reactance of the same machine, then synchronous reactance Xs is
 (a) Xs = 0.5 Xa (b) Xa = 0.5 (Xa – Xl) (c) Xs = Xa + Xl (d) Xs < Xa
54.
An infinite bus in power system is
 (a) A small system whose voltage varies with the power exchange between the synchronous machine and bus (b) A large system whose voltage and frequency varies with the power exchange between synchronous machine and bus (c) A large system whose voltage and frequency remains constant independent of power exchange between synchronous machine and bus (d) A large system with infinite voltage
55.
Per unit impedance of a circuit element is 0.3. if the base kV and base MVA are halved, then the new value of the per unit impedance of the circuit element will be
 (a) 0.3 (b) 0.6 (c) 0.003 (d) 0.006
56.
As compared to sending end voltage, the receiving end voltage of a short line under no load condition is
 (a) Higher (b) Lower (c) Remains same (d) Insufficient data
57.
Which of the following voltage regulation is considered to be the best?
 (a) 2% (b) 30% (c) 70% (d) 98%
58.
Regulation of a line at full load 0.8 power factor (lag) is 12%. The regulation at full load 0.8 power factor (lead) can be
 (a) 24% (b) 18% (c) 12% (d) 4%
59.
If in a short transmission line, resistance and inductive reactance are found to be equal and regulation appears to be zero then load will
 (a) Have unity power factor (b) Have zero power factor (c) Be 0.707(lead) (d) Be 0.707(lag)
60.
For a short line if the receiving end voltage is equal to sending end voltage under loaded condition
 (a) Sending end power factor is unity (b) Receiving end power factor is unity (c) Sending end power factor is leading (d) Receiving end power factor is leading
Showing 51 to 60 out of 135 Questions