Top 250+ Solved Testing and Commissioning of Electrical Equipment’s MCQ Questions Answer
Q. Admittance relay
a. Nondirectional relay
b. Directional relay
c. Differential relay
d. None of the above
Q. The relay used for feeder protection is
a. Under voltage relay
b. Translay relay
c. Thermal relay
d. Buchholz relay
Q. Which relay is used to detect and protect internal fault in a transformer ?
a. Buchholz relay
b. Directional relay
c. Thermal relay
d. Distance relay
Q. Which one of the following relay has the capability of anticipating the possiblemajor fault in a transformer ?
a. Over-current relay
b. Differential relay
c. Buchholz relay
d. Over fluxing relay
Q. Zero sequence current is used for relaying purpose only in the case of
a. Phase over current really
b. Phase impedance relay
c. Ground over current relay
d. Ground impedance relay
Q. To prevent mal operation of differentially connected relay while energising atransformer, the relay restraining coil is biased with
a. Second harmonic current
b. Third harmonic current
c. Fifth harmonic current
d. Seventh harmonic current
Q. How many relays are used to detect interphase fault of a three line system?
a. One
b. Two
c. Three
d. Six
Q. Which is the main relay for protecting up to 90% of the transmission line-length inthe forward direction?
a. Directional over current relay
b. Mho relay
c. Carrier current protective relay
d. Impedance relay
Q. For protection of parallel feeders fed from one end, the relays required are
a. Nondirectional relays at the source end and directional relay at the load end
b. Nondirectional relay at both ends
c. Directional relay at source end and nondirectional relay at load end
d. Directional relay at both ends
Q. Relays can be designed to respond to changes in
a. Resistance, reactance or impedance
b. Voltage and current
c. Light intensity
d. All of the above
Q. DC shunt relays are made of
a. Few turns of thin wire
b. Few turns of thick wire
c. Many turns of thin wire
d. Many turns of thick wire
Q. In order that current should flow without causing excessive heating or voltagedrop, 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. Interruption of large currents by relay requires
a. Arc suppressing blow out coils
b. Wide separation of the open contacts
c. High speed opening of contacts
d. All of the above
Q. To protect most of the electrical equipment handling low power, the types of relaysused are
a. Thermocouple
b. Electronic and bimetallic
c. Both A and B
d. None of the above
Q. ............. Relays are used for phase faults on long line
a. Impedance
b. Reactance
c. Either of the above
d. None of the above