Electrical Engineering Questions and Answers Switchgear Protections - Set 07 - ObjectiveBooks

Electrical Engineering Questions and Answers Switchgear Protections - Set 07

Practice Test: Question Set - 07


1. Which of the following statements is incorrect?
    (A) Station batteries are used to operate relay only
    (B) The lightning arresters are basically surge diverters
    (C) An impedance relay has maximum fault current when fault occurs near the relay
    (D) A high speed relay has an operation of 1 to 2 cycles

2. H.R.C. fuses provide best protection against
    (A) Overload
    (B) Reverse current
    (C) Open-circuits
    (D) Short-circuits

3. A _________ is used to measure the stator % winding temperature of the generator.
    (A) Thermocouple
    (B) Pyrometer
    (C) Resistance thermometer
    (D) Thermometer

4. The material used for fuse must have
    (A) Low melting point and high specific resistance
    (B) Low melting point and low specific resistance
    (C) High melting point and low specific resistance
    (D) Low melting point and any specific resistance

5. A thermal protection switch can protect against
    (A) Short-circuit
    (B) Temperature
    (C) Overload
    (D) Over voltage

6. Oil switches are employed for
    (A) Low currents circuits
    (B) Low voltages circuits
    (C) High voltages and large currents circuits
    (D) All circuits

7. When a transmission line is energized, the wave that propagates on it is
    (A) Current wave only
    (B) Voltage wave only
    (C) Both (A) and (B)
    (D) Power factor wave only

8. Ungrounded neutral transmission system is not recommended because of system
    (A) Insulation being overstressed due to over voltages
    (B) Insulation overstress may lead to failure and subsequent phase to phase faults
    (C) Being inadequately protected against ground fault
    (D) All of the above

9. For which of the following protection from negative sequence currents is provided?
    (A) Generators
    (B) Motors
    (C) Transmission line
    (D) Transformers

10. Series capacitors are used to
    (A) Compensate for line inductive reactance
    (B) Compensate for line capacitive reactance
    (C) Improve line voltage
    (D) None of the above

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