Testing And Commissioning Of Electrical Equipment’S Set 11

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This set of Testing and Commissioning of Electrical Equipment’s Multiple Choice Questions & Answers (MCQs) focuses on Testing And Commissioning Of Electrical Equipment’S Set 11

Q1 | Where severe synchronising swing occur, the relay employed is
  • Impedance relay
  • Mho relay
  • Reactance relay
  • Induction relay
Q2 | For the protection of lines against faults involving variable fault resistance, thepreferred relaying scheme is a
  • Plain impedance relay
  • Directional over-current relay
  • Mho relay
  • Reactance relay
Q3 | For ground fault we prefer
  • Plain impedance relay
  • Directional over current relay
  • Mho relay
  • Reactance relay
Q4 | Admittance relay
  • Nondirectional relay
  • Directional relay
  • Differential relay
  • None of the above
Q5 | The relay used for feeder protection is
  • Under voltage relay
  • Translay relay
  • Thermal relay
  • Buchholz relay
Q6 | Which relay is used to detect and protect internal fault in a transformer ?
  • Buchholz relay
  • Directional relay
  • Thermal relay
  • Distance relay
Q7 | Which one of the following relay has the capability of anticipating the possiblemajor fault in a transformer ?
  • Over-current relay
  • Differential relay
  • Buchholz relay
  • Over fluxing relay
Q8 | Zero sequence current is used for relaying purpose only in the case of
  • Phase over current really
  • Phase impedance relay
  • Ground over current relay
  • Ground impedance relay
Q9 | To prevent mal operation of differentially connected relay while energising atransformer, the relay restraining coil is biased with
  • Second harmonic current
  • Third harmonic current
  • Fifth harmonic current
  • Seventh harmonic current
Q10 | How many relays are used to detect interphase fault of a three line system?
  • One
  • Two
  • Three
  • Six
Q11 | Which is the main relay for protecting up to 90% of the transmission line-length inthe forward direction?
  • Directional over current relay
  • Mho relay
  • Carrier current protective relay
  • Impedance relay
Q12 | For protection of parallel feeders fed from one end, the relays required are
  • Nondirectional relays at the source end and directional relay at the load end
  • Nondirectional relay at both ends
  • Directional relay at source end and nondirectional relay at load end
  • Directional relay at both ends
Q13 | Relays can be designed to respond to changes in
  • Resistance, reactance or impedance
  • Voltage and current
  • Light intensity
  • All of the above
Q14 | DC shunt relays are made of
  • Few turns of thin wire
  • Few turns of thick wire
  • Many turns of thin wire
  • Many turns of thick wire
Q15 | In order that current should flow without causing excessive heating or voltagedrop, the relay contacts should
  • Have low contact resistance
  • Be clean and smooth
  • Be of sufficient size and proper shape
  • Have all above properties
Q16 | Interruption of large currents by relay requires
  • Arc suppressing blow out coils
  • Wide separation of the open contacts
  • High speed opening of contacts
  • All of the above
Q17 | To protect most of the electrical equipment handling low power, the types of relaysused are
  • Thermocouple
  • Electronic and bimetallic
  • Both A and B
  • None of the above
Q18 | ............. Relays are used for phase faults on long line
  • Impedance
  • Reactance
  • Either of the above
  • None of the above
Q19 | ........ Relays is preferred for phase fault on short transmission line
  • Induction type
  • Reactance
  • Impedance
  • None of the above
Q20 | The under voltage relay can be used for
  • Generators
  • Bus bars
  • Transformers
  • All of the above
Q21 | The single phasing relays are used for the protection of
  • Single phase motors only
  • Two phase motors only
  • Two single phase motor running in parallel
  • Three phase motors
Q22 | The inverse definite mean time relays are used for over current and earth faultprotection of transformer against
  • Heavy loads
  • Internal short circuits
  • External short circuits
  • All of the above
Q23 | In a static over current relay, inverse time characteristics are obtained by
  • A transistor amplifier
  • An integrating circuit
  • A transistor switch
  • A differentiating circuit
Q24 | In the case of transmission line protection, over current relay is used
  • Only up to 110 KV
  • Only up to 220 KV
  • Only up to 50 KV
  • Only up to 1100 KV
Q25 | Directional over current relays have two exciting coils connected across
  • CT secondaries of two different phases
  • VT secondaries of two different phases
  • CT and VT secondaries of same phases
  • CT and VT secondaries of two different phases