1. The HVDC converter
Ans - Consumes 50% of the real power
2. A back to back HVDC link can be advantageous compared to AC primarily because
Ans - Of controlled power glow
3. A 12-pulse bridge is preferred in HVDC because
Ans - It eliminates certain harmonics
4. Fault on a two terminal DC link is removed by
Ans - Current control of converters
5. Which of following are used to reduce short circuit fault currents
a) Reactors
b) Resistors
c) Capacitors
d) Parallel combination of all these
Ans: (a)
6. Which of the following type of reactors are popularly used in power systems?
a) Compensation reactors
b) Current limiting reactors
c) Suppression or Peterson reactors
d) All of these
Ans: (d)
7. Oil immersed type reactor has the advantage of
a) Higher safety against flashover
b) Smaller size with large thermal capacity
c) Limiting the fault voltage
d) Both (a) and (b) above
Ans: (a)
8. Shunt reactors are connected with transmission lines for
a) Limiting fault current
b) Absorbing reactive power
c) Absorbing high voltage surges
d) Limiting fault current
Ans: (b)
9. Which of the following method of protection is used to achieve earth fault operation?
a) Core balance method
b) Relay connected with neutral to ground
c) Frame leakage method
d) None of these
Ans: (a)
10. Minimum faults occur in which of the following power system equipment?
a) Transformer
b) Switch gear
c) CT, PT
d) Alternator
Ans: (d)
11. Large internal faults below oil level are protected by
a) Mho and ohm relays
b) Horn gap and temperature relay
c) Merz Price percentage differential relay
d) Earth fault and positive sequence relay
Ans: (b)
12. Interruption due to fault and maintenance is minimum in
a) Main and transfer bus arrangement
b) Single bus arrangement
c) Sectionalized single bus arrangement
d) Double bus, double breaker arrangement
Ans: (d)
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