Top 250+ Solved Testing and Commissioning of Electrical Equipment’s MCQ Questions Answer
Q. ........ Relays is preferred for phase fault on short transmission line
a. Induction type
b. Reactance
c. Impedance
d. None of the above
Q. The under voltage relay can be used for
a. Generators
b. Bus bars
c. Transformers
d. All of the above
Q. The single phasing relays are used for the protection of
a. Single phase motors only
b. Two phase motors only
c. Two single phase motor running in parallel
d. Three phase motors
Q. The inverse definite mean time relays are used for over current and earth faultprotection of transformer against
a. Heavy loads
b. Internal short circuits
c. External short circuits
d. All of the above
Q. In a static over current relay, inverse time characteristics are obtained by
a. A transistor amplifier
b. An integrating circuit
c. A transistor switch
d. A differentiating circuit
Q. In the case of transmission line protection, over current relay is used
a. Only up to 110 KV
b. Only up to 220 KV
c. Only up to 50 KV
d. Only up to 1100 KV
Q. Directional over current relays have two exciting coils connected across
a. CT secondaries of two different phases
b. VT secondaries of two different phases
c. CT and VT secondaries of same phases
d. CT and VT secondaries of two different phases
Q. The domains of power system where directional over current relay is indispensableare
a. In case of parallel feeder protection
b. In case of ring main feeder protection
c. Both A and B
d. None of the above
Q. In an inverse definite minimum time, electromagnetic type over current relay, theminimum time feature is achieved because of
a. Saturation of the magnetic circuit
b. Proper mechanical design
c. Appropriate time delay element
d. Electromagnetic damping
Q. Impedance relay can be used for
a. Phase faults only
b. Earth faults only
c. Both earth and phase faults
d. None of the above
Q. Impedance relay may use
a. Balance beam structure
b. Induction cup structure
c. Shaded pole structure
d. Either A or B
Q. An impedance is relay is a
a. Voltage restrained over current relay
b. Voltage restrained directional relay
c. Directional restrained over current relay
d. Directional restrained over voltage relay
Q. On transient fault OC and impedance relay
a. Under reaches
b. Over reaches
c. Reach unaffected
d. None of the above
Q. Threshold characteristics of a plain impedance relay in a complex Z plane is a
a. Circle passing through origin
b. Circle with the centre at the origin
c. Straight line passing through origin
d. Straight line offset from the origin
Q. The structure used in reactance relay is
a. Induction cup
b. Double induction loop
c. Single induction loop
d. Either A or B