Computer Programming MCQs

5739 MCQs  (Page 195 of 574)

Directional relays are based on flow of____________?
A. power
B. current
C. voltage wave
D. all of the above
Large internal faults are protected by_______________?
A. merz price percentage differential protection
B. mho and ohm relays
C. horn gaps and temperature relays
D. earth fault and positive sequence relays
In a circuit breaker the basic problem is to________________?
A. maintain the arc
B. extinguish the arc
C. transmit large power
D. emit the ionizing electrons
Protective relays are devices that detect abnormal conditions in electrical circuits by measuring_____________?
A. current during abnormal condition
B. voltage during abnormal condition
C. constantly the electrical quantities which differ during normal and abnormal conditions
D. none of the above
A differential relay measures the vector difference between_________________?
A. two currents
B. two voltages
C. two or more similar electrical quantities
D. none of the above
An efficient and a well designed protective relaying should have_____________?
A. good selectivity and reliability
B. economy and simplicity
C. high speed and selectivity
D. all of the above
Relays can be designed to respond to changes in________________?
A. resistance, reactance or impedance
B. voltage and current
C. light intensity
D. temperature
The relay operating speed depends upon_________________?
A. the spring tension
B. the rate of flux built up
C. armature core air gap
D. all of the above
The current zero interruption, in oil and air blast circuit breakers, is achieved by_______________?
A. lengthening of the gap
B. cooling and blast effect
C. both a. and b
D. deionizing the oil with forced air