Top 150+ Solved Switch Gear and Protection MCQ Questions Answer
Q. 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
Q. In order that current should flow without causing excessive heating orvoltage drop, the relay contacts should
a. have low contact resistance
b. be clean and smooth
c. be of sufficient size and proper shape
d. have all above properties
Q. Circuit breakers usually operate under
a. transient state of short-circuit current
b. sub-transient state of short-circuit current
c. steady state of short-circuit current
d. after D.C. component has ceased
Q. Circuit breakers are essentially
a. current carrying contacts called electrodes
b. arc extinguishers
c. circuits to break the system
d. tr
Q. 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
Q. Air blast circuit breaker is used for
a. over currents
b. short duty
c. intermittant duty
d. repeated duty
Q. 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
Q. Burden of a protective relay is the power
a. required to operate the circuit breaker
b. absorbed by the circuit of relay
c. developed by the relay circuit
d. none of the above
Q. 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
Q. A transmission line is protected by
a. inrush protection
b. distance protection
c. time graded and current graded over current protection
d. both (b) and (c)
Q. 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
Q. When a transmission line is energized, the wave that propagates on itis
a. current wave only
b. voltage wave only
c. both (a) and (b)
d. power factor wave only
Q. Protective relays are devices that detect abnormal conditions inelectrical 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
Q. The voltage appearing across the contacts after opening of the circuit breaker is called______voltage.
a. recovery
b. surge
c. operating
d. arc