This set of FACTS Multiple Choice Questions & Answers focuses on “Characteristics and Requirements of Power Electronic Devices – Set 3”.
1. Series reactors are never required for higher rating of FACTS converters.
a) True
b) False
View Answer
Explanation: Series reactors are never required for higher rating of FACTS converters. Actually, a large inductor is connected with the high rated converter. It acts as a filter.
2. Series reactor connected with a high rated FACTS converter _______
a) reduces harmonics
b) helps in short circuit protection
c) increases the output voltage
d) provides storage
View Answer
Explanation: Series reactor connected with a high rated FACTS converter reduces harmonics. It does not perform the other functions listed in the options. Being connected in series with the high rated converter it filters the harmonics from the output of the converter.
3. DC storage is required for higher rating of FACTS converters.
a) True
b) False
View Answer
Explanation: DC storage is required for higher rating of FACTS converters. It is aimed to provide the active power requirement of the transmission lines during abnormal conditions. Therefore, for higher rating of FACTS converters the sizes of DC storages are increased.
4. Insertion transformer connected in FACTS _______
a) reduces harmonics
b) helps in short circuit protection
c) increases the output voltage
d) provides storage
View Answer
Explanation: Insertion transformer connected in FACTS increases the output voltage. Basically it is connected between the output of the converter and the transmission line. So it increases the output voltage of the converter to feed the transmission line with the desired voltage value.
5. Frequency collapse is not a stability criterion of FACTS.
a) True
b) False
View Answer
Explanation: Frequency collapse is a stability criterion of FACTS. Basically it indicates frequency stability of the system. It may lead to sustained frequency swings or oscillations leading to tripping of devices connected.
6. Frequency stability may be either a short time phenomenon or a long-term phenomenon.
a) True
b) False
View Answer
Explanation: Frequency stability may be either a short time phenomenon or a long-term phenomenon. This is because the frequency collapse may lead to a condition where the connected devices in their active states will respond such that their characteristic frequency response will change from a fraction of a second to few minutes. The affected devices may be the generators or loads
7. Frequency collapse does not depend upon the loading condition of the system concerned.
a) True
b) False
View Answer
Explanation: Frequency collapse depends upon the loading condition of the system concerned. It also corresponds to the response behavior of devices at the generating end such as prime mover. The duration of frequency collapse also depends on the type of disturbance.
8. Transient stability deals with surges occurring for ________
a) a very short duration but with large magnitude
b) a very large duration but with large magnitude
c) a very large duration but with small magnitude
d) a very short duration but with small magnitude
View Answer
Explanation: Transient stability deals with surges occurring for a very short duration but with large magnitude. Sudden switching on of heavy loads causes a transient disturbance. It results in a considerable voltage drop of system for a short period of time.
9. Any FACTS series device cannot operate in ‘no controlling mode’.
a) True
b) False
View Answer
Explanation: Any FACTS series device can operate in no controlling mode. It can operate in voltage compensating mode. Also it is used in impedance compensating mode.
10. ________ is the order of harmonics of a 12-pulse converter.
a) 12n+1
b) 12n±1
c) 24n±1
d) 48n±1b
View Answer
Explanation: 12n±1 is the order of harmonics of a 12-pulse converter. 24n±1 is the order of harmonics of a 24-pulse converter. 48n±1 is the order of harmonics of a 48-pulse converter.
11. A single phase full wave bridge converter exhibits order of harmonics.
a) 2n±1
b) 2n-1
c) 2n+1
d) 2n
View Answer
Explanation: A single phase full wave bridge converter exhibits 2n±1 order of harmonics. A single phase full wave bridge converter results in a square waveform of voltage. This output voltage is pulsating in nature.
12. The full form of PWM is ________
a) Pulse Width Modifier
b) Pulse Weight Modulation
c) Positive Width Modulation
d) Pulse Width Modulation
View Answer
Explanation: The full form of PWM is Pulse Width Modulation. This technique may be applied to a VSC or a CSC. Basically it reduces the harmonics from the output voltage of the converter.
13. UPFC can work as a voltage regulator.
a) True
b) False
View Answer
Explanation: UPFC can work as a voltage regulator. It finds application as line impedance compensator. Also it is useful as power angle regulator.
14. IPFC consists of ________ dc-ac converters.
a) n-number
b) one
c) at least two
d) at most three
View Answer
Explanation: IPFC consists of n-number of dc-ac converters. Each of the dc-ac converters will provide series compensation. Thus it can cater to compensation of ‘n’ different lines each being fed with a single converter.
15. GTO is used as ________ in GCSC.
a) switching device
b) power device
c) storage device
d) compensating device
View Answer
Explanation: GTO is used as a switching device in GCSC. It is connected in parallel with the capacitor. The function of GCSC is similar to that of TCR.
Sanfoundry Global Education & Learning Series – Flexible AC Transmission System (FACTS).
To practice all areas of Flexible AC Transmission System (FACTS), here is complete set of 1000+ Multiple Choice Questions and Answers.
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