power-system-protection-mcqs

Power System Protection MCQs Part 5

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a. Usually, busbars are not protected because:

  1. Backup protection is quite enough
  2. Usually, earth faults occur which don’t require fast protection
  3. CT’s are very expensive
  4. All of these

Correct answer: 4. All of these

b. A distance relay actually measures:

  1. Current
  2. Voltage
  3. Impedance
  4. None of these

Correct answer: 3. Impedance

c. The loss of excitation in a generator is classified as:

  1. Mechanical fault
  2. Electrical fault

Correct answer: 2. Electrical fault

d. Most unit protection schemes are based on:

  1. Merz Price principle
  2. Combinational Buchholz relay system
  3. Induction principle
  4. None of these

Correct answer: 1. Merz Price principle

e. Generally, a Frame-leakage check is used for protection of:

  1. Alternator
  2. DC generators
  3. Transformers
  4. Bus bars

Correct answer: 4. Bus bars

f. ___________ can be used to protect insulation failure in a.c generators:

  1. Resistors
  2. Reactors
  3. Transformers
  4. All of these

Correct answer: 4. All of these

g. Interturn faults on an alternator are _________ and are ___________ detectable:

  1. Common, easily
  2. Uncommon, easily
  3. Uncommon, not easily
  4. Common, not easily

Correct answer: 3. Uncommon, not easily

h. Peterson coil is actually a:

  1. Tunable reactor
  2. Simple resistors
  3. Transformer with five windings
  4. A reactance (either cap or inductive)

Correct answer: 1. Tunable reactor

i. The term effective earthing refers to the earthing which is done through:

  1. Resistance
  2. Reactance
  3. Transformer
  4. None of these

Correct answer: 4. None of these

j. A fuse acts as:

  1. Fault detector
  2. Interruptor
  3. Both of these
  4. None of these

Correct answer: 3. Both of these

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