This set of FACTS Multiple Choice Questions & Answers (MCQs) focuses on “Characteristics and Requirements of Power Electronic Devices – Set 2”.
1. QBT stands for________
a) Quadrature Boosting Transformer
b) Quadrature Boosting Thyristor
c) Quality Boosting Transformer
d) Quadrature Back-to-back Transformer
View Answer
Explanation: QBT stands for Quadrature Boosting Transformer. It is prevalent in phase angle regulators. It finds use in conventional phase shifting applications.
2. Voltage regulation is the addition of an appropriate ________ to the system.
a) in-phase voltage
b) out-of-phase voltage
c) in-phase current
d) quadrature voltage
View Answer
Explanation: Voltage regulation is the addition of an appropriate in-phase voltage to the system. This voltage regulation induces a change in magnitude of the system to which it is applied. The change may be an increase or a decrease.
and or a quadrature component to the prevailing terminal (bus) in order to or angle to the value specified (or desired).
3. Phase angle regulation is the addition of an appropriate ________ to the system.
a) in-phase voltage
b) out-of-phase voltage
c) in-phase current
d) quadrature voltage
View Answer
Explanation: Phase angle regulation is the addition of an appropriate quadrature voltage to the system. The change may vary from +90° to -90°.This phase-angle regulation cannot induce a change in magnitude of the system to which it is applied.
4. Voltage regulation is the addition of voltage with an appropriate phase reference with respect to ________
a) terminal voltage of the system
b) terminal current of the system
c) terminal voltage of the voltage regulator
d) terminal voltage of the voltage regulator
View Answer
Explanation: Voltage regulation is the addition of voltage with an appropriate phase reference with respect to the terminal voltage of the system. The phase reference is not with respect to the terminal voltage of the voltage regulator. Thus voltage regulator controls or regulates the system to which it is connected.
5. Phase-angle adjustment through tap-changing transformer is associated with ________ of the system.
a) active power control
b) reactive power control
c) active current control
d) reactive current control
View Answer
Explanation: Phase-angle adjustment through tap-changing transformer is associated with reactive power control of the system. It refers to the addition of quadrature voltage to the system. Thus phase-angle regulator may control or regulate the system to which it is connected.
6. Voltage adjustment through tap-changing transformer is associated with ________ of the system.
a) active power control
b) reactive power control
c) active current control
d) reactive current control
View Answer
Explanation: Voltage adjustment through tap-changing transformer is associated with reactive power control of the system. It refers to the addition of in-phase voltage to the system. Thus voltage regulator may control or regulate the system to which it is connected.
7. Phase-angle regulation is the addition of voltage with an appropriate phase reference with respect to ________
a) terminal voltage of the system
b) terminal current of the system
c) terminal voltage of the Phase-angle regulator
d) terminal voltage of the Phase-angle regulator
View Answer
Explanation: Phase-angle regulation is the addition of voltage with an appropriate phase reference with respect to the terminal voltage of the system. The phase reference is not with respect to the terminal voltage of the voltage regulator. Thus Phase-angle regulator controls or regulates the system to which it is connected.
8. QBT inherently always maintains the voltage magnitude constant irrespective of any angular adjustment.
a) True
b) False
View Answer
Explanation: QBT cannot always maintain the voltage magnitude constant irrespective of its angular adjustment. It does maintain constant voltage independent of its angular displacement only for relatively small values of the later. However, a complex winding arrangement may be required to make QBT maintain constant voltage.
9. ________ maintains the desired voltage profile along the transmission line in spite of changing real power demand.
a) Reactive shunt compensation
b) Active shunt compensation
c) Reactive series compensation
d) Active shunt compensation
View Answer
Explanation: Reactive shunt compensation maintains the desired voltage profile along the transmission line in spite of changing real power demand. It controls the voltage variation along the transmission line very effectively. Thus it helps to maintain specified voltage level at the load end of a sub-transmission or distribution system.
10. Without proper reactive shunt compensation techniques, an increase in real power transmission will result in ________ at the end-voltage generators.
a) an increase of reactive power demand
b) a decrease of reactive power demand
c) no change of reactive power demand
d) no change of power demand (reactive/active)
View Answer
Explanation: Without proper reactive shunt compensation techniques, an increase in real power transmission will result in an increase of reactive power demand at the end-voltage generators. This, in turn, will lead to an increase in voltage variation along the transmission line. Thus adequate reactive shunt compensation is required for proper flow of reactive and real power and maintaining a desired voltage profile at load end.
11. FACTS power transmission is economical for long–distance transmission system.
a) True
b) False
View Answer
Explanation: FACTS power transmission is NOT economical for long–distance transmission system. Rather it is expensive. Actually HVDC power transmission is economical for long–distance transmission system.
12. Reactive power control is not required in FACTS.
a) True
b) False
View Answer
Explanation: Reactive power control is required in FACTS. This is because in this system, the transmission system deals with AC voltage. In FACTs, the power flow can be controlled with various FACTS devices.
13. For the same rating the cost of HVDC is similar to that of FACTS.
a) True
b) False
View Answer
Explanation: For the same rating the cost of HVDC is NOT similar to that of FACTS. The cost of FACTS is les than the cost of HVDC. In HVDC there is no need to control reactive power as the system exhibits DC voltage.
14. An asynchronous tie is possible in FACTS.
a) True
b) False
View Answer
Explanation: An asynchronous tie is NOT possible in FACTS. In FACTS, proper synchronization is required as any two systems here cannot be connected without proper synchronization. Actually an asynchronous tie is possible in HVDC.
15. Snubber circuit is not used in FACTS.
a) True
b) False
View Answer
Explanation: Snubber circuit is used in FACTS. Higher rated converters demand every valve to be protected against high voltage and high current. Snubber circuit connected across every valve does it efficiently.
Sanfoundry Global Education & Learning Series – Flexible AC Transmission System (FACTS).
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