621. The equal area criterion of stability is applicable to
A. Two machine system and infinite bus bars
B. One machine system and infinite bus bars
C. Multi-machine system only
D. None of the above
Ans.: B
622. The power transmission capacity of the transmission line is
A. Inversely proportional to the square of the voltage
B. Proportional to the voltage
C. Inversely proportional to the voltage
D. Proportional to the square of the operating voltage
Ans.: D
623. If the torque angle ‘delta’ increases indefinitely, the system indicates
A. Steady state stability
B. Permanent stability
C. Instability
D. None of the above
Ans.: C
624. Resistance switching is normally employed in
A. All breakers
B. Bulk oil breaker
C. Minimum oil breaker
D. Air-blast circuit breaker
Ans.: D
625. Series capacitors are used to
A. Improve line frequency and eliminate harmonics
B. Compensate for line inductive reactance
C. Neutralize line capacitive reactance
D. None of the above
Ans.: B
626. Over fluxing protection is normally recommended for
A. Generator transformers in power stations
B. Auto-transformers in power stations
C. Station transformers in power stations
D. Distribution transformers
Ans.: A
627. In general AC distribution systems, arc interruption in vacuum circuit breakers are designed to function in a time period of
A. One cycle
B. Two to three cycles
C. Within ten cycles
D. None of the above
Ans.: A
628. Systems for Protection from negative sequence current is provided normally for
A. Transformers
B. Generators
C. Transmission lines
D. Motors
Ans.: B
629. Bundled conductors are mainly used in high voltage overhead transmission lines to
A. Reduce line loss
B. Reduce harmonics
C. Reduce corona
D. Increase strength
Ans.: C
630. Surge impedance of overhead transmission line is normally in the order of
A. 1 – 5 ohms
B. 20 – 30 ohms
C. 300 – 500 ohms
D. 300000 – 500000 ohms
Ans.: C
631. The bode diagram approach is applied to
A. Non-minimum phase network
B. Minimum phase network
C. Any network of a control system
D. None of the above
Ans.: B
632. Which of the following methods is the strongest tool to determine the stability and the transient response of the system?
A. Routh-Hurwitz criterion
B. Bode plot
C. Nyquist plot
D. Root locus
Ans.: D
633. If the gain of a critically damped system is increased, it will become
A. Under damped system
B. Over damped system
C. Oscillatory system
D. Critically damped system
Ans.: A
634. The frequency domain and time domain are related through
A. Laplace transform
B. Gauss elimination
C. Both (a) and (b)
D. None of the above
Ans.: A
635. A system with characteristic equation S^4 + 2S^5 + 18S+18= 0 will have closed loop poles such that
A. All poles lie in the left half of the s-plane
B. All poles lie in the right half of the s-plane
C. Two poles lie symmetrically on the imaginary axis of the s-plane.
D. No pole lies on the imaginary axis of the s-plane.
Ans.: C