Electrical Distribution Systems Mid - II, November - 2014

1.The most common type of fault on a single phase distribution system is
  • Line to line
  • L-L-G
  • L-G
  • L-L-L-G
Answer: C
2.An impedance relay is used for
  • Distance protection
  • over current protection
  • parallel feeder protection
  • none of the above
Answer: A
3.Which of the following is /are objective(s) of distribution system protection?
  • To minimize the duration of a fault
  • To minimize the number of consumers affected by the fault
  • To protect the consumers’ apparatus
  • All the above
Answer: D
4.Which of the following faults has least probability of occurrence?
  • LG
  • LL
  • LL
  • 3-Ø faults
Answer: D
5.Which of the following is/are unsymmetrical fault(s)?
  • LG
  • LL
  • LLG
  • All the above
Answer: D
6.Which of the following can be operated to provide both lagging and leading reactive power?
  • Series capacitors
  • shunt capacitors
  • synchronous motors
  • Any of the above
Answer: C
7.A 50 KW induction motor has a power factor of 0.707. The reactive power consumed by it is
  • 35.35 KVAR
  • 50 KVAR
  • 30 KVAR
  • 20 KVAR
Answer: B
8.The benefits of power factor improvement include
  • Better voltage regulation
  • Reduced system losses
  • both (a) &(b)
  • None of the above
Answer: C
9.With a step voltage regulator , the voltage is
  • Boosted
  • reduced
  • boosted or reduced in steps
  • Boosted or reduced continuously
Answer: C
10.Which of the following can be used for voltage control?
  • Induction regulators
  • Tap changing transformers
  • Voltage boosters
  • All the above
Answer: D
11.An over current protective device that trips and recloses a preset number of times is called an __________________.
Answer: Automatic circuit recloser
12.A device which senses an abnormal situation in the circuit is ___________.
Answer: Relay
13._____________ is an automatic interrupting device which is capable of breaking and reclosing a circuit under faulted or normal operating conditions.
Answer: Circuit breaker
14.A ground wire is run over the overhead transmission lines, to protect them from _________________ over voltages.
Answer: Lightning
15.The volt-ampere characteristic of a lightning arrester is given by the equation_________________.
Answer: I=KVn
16.The equivalent circuit of a short line consists of a resistance and________________ in series.
Answer: Inductance
17.The value of power factor of an ideal inductor is ___________.
Answer: 0
18.The difference between sending end and receiving end voltages of a line is termed as _____________.
Answer: Voltage drop
19.The difference between maximum and minimum voltages, without voltage dips due to motor starting is called as _______________.
Answer: Voltage spread
20.Most commonly used voltage control in substations is ____________________.
Answer: Transformer tap changing