This set of FACTS Multiple Choice Questions & Answers (MCQs) focuses on “TCVR”.
1. TCVR is the abbreviation of ________
a) Thyristor-Controlled Voltage Regulator
b) Thyristor-Controlled Voltage Resistor
c) Thyristor-Commuted Voltage Regulator
d) Thyristor-Controlled Voltage Receiver
View Answer
Explanation: TCVR is the abbreviation of Thyristor-Controlled Voltage Regulator. It consists of a thyristor controlled transformer or ac-to-ac voltage converter. It provides variable in-phase voltage.
2. The circuit configuration of TCVR is similar to that of breaker-switched capacitors, reactors and mechanical tap-changing transformers.
a) True
b) False
View Answer
Explanation: The circuit configuration of TCVR is similar to that of breaker-switched capacitors, reactors and mechanical tap-changing transformers. It appears so because TCVR employs reactive impedances and tap-changing transformers with conventional thyristor valves (switches) as controlled elements. However, TCVR exhibits much faster response and sophisticated operation controls than the later.
3. TCVR can provide reactive compensation.
a) True
b) False
View Answer
Explanation: TCVR cannot provide reactive compensation. This is because it is unable to generate reactive power. However, TCVR can exchange both real and reactive power.
4. TCVR always consists of a regular transformer without any thyristor.
a) True
b) False
View Answer
Explanation: TCVR may be a regular transformer with thyristors employed in it. The device employed is a thyristor-controlled tap changer. With it, the TCVR injects variable ac voltage into the line.
5. TCVR injects ________ with the line.
a) variable ac voltage in series
b) variable dc voltage in shunt
c) variable ac voltage in series
d) variable ac voltage in shunt
View Answer
Explanation: TCVR injects variable ac voltage in series with the line. The variable ac voltage is of the same phase with the line. Thus it controls the flow of reactive power between two connected systems.
6. TCVR exhibits reactive power control.
a) True
b) False
View Answer
Explanation: TCVR exhibits reactive power control. IPFC employs Voltage Sourced Converter as its building block. However, unlike UPFC, IPFC is NOT a combined series shunt FACTS controller.
7. TCVR exhibits voltage control.
a) True
b) False
View Answer
Explanation: TCVR exhibits voltage control. However, IPFC cannot support proper load balancing of transmission lines independently. To achieve this, the IPFC scheme must operate with independently controllable reactive series compensation for each individual line in the transmission network.
8. TCVR exhibits damping oscillations.
a) True
b) False
View Answer
Explanation: TCVR exhibits damping oscillations. The ratio of reactive to resistive line impedance, especially when very low, poses a problem to IPFC. The employed compensating converters in IPFC scheme are linked together at their dc terminals.
9. TCVR exhibits transient and dynamic stability.
a) True
b) False
View Answer
Explanation: TCVR exhibits transient and dynamic stability. The IPFC houses a number of Static Synchronous Series Compensators. It takes care for compensation of each transmission line individually.
10. TCVR exhibits voltage stability.
a) True
b) False
View Answer
Explanation: TCVR exhibits voltage stability. IPFC employs series capacitive compensation. Its compensation is based on SSSC principle or fixed thyristor-controlled directive.
11. Practically TCVR is a relatively high cost Controller.
a) True
b) False
View Answer
Explanation: Practically TCVR is NOT a high cost Controller. TCVR is a relatively low cost Controller employed in FACTS. It does control the reactive power flow very effectively.
12. In TCVR, the voltage regulation is obtained by injecting voltage in ________
a) phase with the system current
b) phase quadrature with the system voltage
c) phase with the system voltage
d) phase quadrature with the system voltage
View Answer
Explanation: In TCVR, the voltage regulation is obtained by injecting voltage in phase with the system voltage. As the name indicates, the thyristor switches are employed to control the injected voltage. This is achieved by controlling the value of the delay angle of thyristors incorporated.
13. TCVR always employs a regular transformer with a thyristor-controlled tap changer.
a) True
b) False
View Answer
Explanation: TCVR may employ a regular transformer with a thyristor-controlled tap changer. Else it may be with a thyristor-controlled ac to ac voltage converter. In both the cases injection of variable ac voltage of the same phase with the line must be ensured.
14. TCVR cannot exhibit continuous control.
a) True
b) False
View Answer
Explanation: TCVR can exhibit continuous control. It can continuously inject variable ac voltage in series with the line. Thus it can continuously control the flow of reactive power between two ac systems.
15. The circuit diagram of TCVR is similar to that of ________
a) thyristor turned-off circuits
b) thyristor turned-on circuits
c) thyristor controlled tap changer
d) thyristor-fired circuits
View Answer
Explanation: The circuit diagram of TCVR is similar to that of thyristor controlled tap changer. Generally the secondary winding of the transformer is split into two parts. One part comprises of switch SW1 and the other part consists of switch SW2.
Sanfoundry Global Education & Learning Series – Flexible AC Transmission System (FACTS).
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