Relays And System Protection Quiz

39 Questions | Total Attempts: 1452

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Relays And System Protection Quiz - Quiz

What do you understand by relays and system protection? Are you ready to take this relays and system protection quiz that we have designed? A protection relay is known as a smart device that is helpful in receiving inputs, comparing them to set points, and providing some outputs. These inputs can be current, voltage, resistance, or even temperature. So, let's see if you understand relays and system protection well enough or not.


Questions and Answers
  • 1. 
    The number of pilot wires required for protecting 3-phase transmission lines using the Translay method of protection is:
    • A. 

      6

    • B. 

      4

    • C. 

      3

    • D. 

      2

  • 2. 
    A Mho relay is a:
    • A. 

      Voltage restrained directional relay

    • B. 

      Voltage controlled over current relay

    • C. 

      Directional restrained over current relay

    • D. 

      Directional restrained over voltage relay

  • 3. 
    If the time operation of a relay for unity TMS is 10 sec, what is the time of operation for 0.5 TMS:
    • A. 

      20

    • B. 

      5

    • C. 

      10

    • D. 

      None

  • 4. 
    The Buckholtz relay protects  a transformer from: 
    • A. 

      All types of internal faults

    • B. 

      A turn to turn fault

    • C. 

      Winding to Winding Fault

    • D. 

      None

  • 5. 
    The purpose of a differential relay on a transformer is to
    • A. 

      Protect against external faults

    • B. 

      Protect against internal faults

    • C. 

      Protect against overvoltage

    • D. 

      Protect against under current

  • 6. 
    Which drawing represents a Balanced Current Relay?
    • A. 
    • B. 
    • C. 
    • D. 
    • E. 
    • F. 
  • 7. 
    A type of relay in which the time of relaying varies directly as the distance of the fault from the station 
    • A. 

      Distance Relay

    • B. 

      Differential Relay

    • C. 

      Overcurrent

    • D. 

      Pilot

  • 8. 
    Which of the following types of relays are used to protect transformers and generators?
    • A. 

      Directional overcurrent Relays

    • B. 

      Differential Relay

    • C. 

      Thermal Relays

    • D. 

      Single Pole Relays

  • 9. 
    What is not a protected equipment in a substation?
    • A. 

      Shunt Equipment Protection

    • B. 

      Bus Protection

    • C. 

      Transformer Protection

    • D. 

      Circuit Breaker Failure Protection

    • E. 

      Under frequency Load Shedding

    • F. 

      Variable condeser

  • 10. 
    A type of relaying which is responsive to the direction of the flow of power and line impedance is normally designed as
    • A. 

      Distance relaying

    • B. 

      Pilot protection

    • C. 

      Power relaying

    • D. 

      Differential relaying/protection

  • 11. 
    Reactance relay is normally preferred for protection against:
    • A. 

      Earth faults only

    • B. 

      Phase Faults only

    • C. 

      3 phase to ground faults

    • D. 

      Single phase ground faults

  • 12. 
    An overhead line with series compensation is protected using:
    • A. 

      Impedance Relay

    • B. 

      Reactance relay

    • C. 

      Mho relay

    • D. 

      None of the above

  • 13. 
    Distance Relays may be directional or non-directional
    • A. 

      True

    • B. 

      False

  • 14. 
    This value is the determinant as to how long a short circuit will remain on a circuit, if uninterrupted by an overcurrent protective device.
    • A. 

      Time of fault

    • B. 

      At what point did the fault occur

    • C. 

      X/R

    • D. 

      Single or 3 phase

  • 15. 
    Used to provide high speed tripping for end zone faults (beyond Zone 1's reach). 
    • A. 

      Directional Over Current

    • B. 

      Distance Relay

    • C. 

      Pilot Schemes

    • D. 

      Out-of-Step Relaying

  • 16. 
    In the short circuit analysis, the rate of decay of fault current depends on:
    • A. 

      L/R ratio

    • B. 

      Single or 3 phase

    • C. 

      At what point did the fault occur

    • D. 

      Time of fault relative to the volatge

  • 17. 
    Used to provide communication channel between the line sections of a terminal to determine if fault is internal or external
    • A. 

      Directional Over Current

    • B. 

      Distance Relay

    • C. 

      Pilot Schemes

    • D. 

      Out-of-Step Relaying

  • 18. 
    If the fault current is 2000 amps, the relay setting is 50% and the C.T. is 400/5, then the plug setting multiplier should be:
    • A. 

      25 amps

    • B. 

      15 amps

    • C. 

      50 amps

    • D. 

      None of the above

  • 19. 
    In this protection scheme the relay at one end detects a fault, it is turned on to signal the other end of the line that a fault has occurred.
    • A. 

      Transfer Tripping

    • B. 

      Directional Comparison

    • C. 

      Phase Comparison

    • D. 

      Pilot-Wire

  • 20. 
    Faults within the protection zone are called?
    • A. 

      Internal faults

    • B. 

      External faults

    • C. 

      Line Faults

    • D. 

      Bus Faults

  • 21. 
    Magnitude of the short circuit depends least based on what?
    • A. 

      Circuit reactance

    • B. 

      Capacity of the generator

    • C. 

      Synchronous Reactance

    • D. 

      Circuit Resistor

  • 22. 
    Faults outside the protection zone are called?
    • A. 

      Internal faults

    • B. 

      External faults

    • C. 

      Line Faults

    • D. 

      Bus Faults

  • 23. 
    In this protection scheme over-current fault detecting relays are used to compare the relative phase angles of the currents at the to terminals.
    • A. 

      Transfer Tripping

    • B. 

      Directional Comparison

    • C. 

      Phase Comparison

    • D. 

      Pilot-Wire

  • 24. 
    What is not a possible zone of protection in a power system?
    • A. 

      Bus Bars

    • B. 

      Lines

    • C. 

      Capacitor or reactor banks

    • D. 

      Utilization equipment

    • E. 

      High pass filters

    • F. 

      Generators

    • G. 

      Transformers

  • 25. 
    In this protection scheme the magnitude and phase angle of the current flowing at each end of the line determine whether an internal fault exists.
    • A. 

      Transfer Tripping

    • B. 

      Directional Comparison

    • C. 

      Phase Comparison

    • D. 

      Pilot-Wire

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