Distinguish between static VAR compensators (SVC) and STATCOMs in terms of reactive power support and response characteristics.

Distinguish between static VAR compensators (SVC) and STATCOMs in terms of reactive power support and response characteristics.

• A. SVC uses battery storage; STATCOM uses mechanical flywheels.
• B. SVC provides variable reactive power through thyristor-controlled reactors and capacitors with slower, voltage-dependent response; STATCOM uses voltage-source converters with fast, bidirectional reactive power support and independent voltage control.
• C. SVC generates active power; STATCOM generates heat.
• D. SVC and STATCOM have identical control characteristics.

Answer: (B)

Reactive power support and how quickly devices respond to changes are the key ideas here. An SVC uses thyristor-controlled reactors and capacitor banks to vary the reactive power exchanged with the grid. The amount of VARs it can inject or absorb is adjusted by changing the firing of the thyristors and the network’s impedance, so its response is relatively slower and tied to the current system voltage. In other words, its effectiveness depends on the bus voltage and the configured reactor/capacitor elements, giving a more voltage-dependent, slower response. A STATCOM, on the other hand, uses a voltage-source converter to produce a controllable output voltage that can inject or absorb reactive power rapidly in both directions. Because it modulates its output as a voltage source, it can regulate the connection-point voltage independently and respond much faster to disturbances, delivering bidirectional reactive power support with a wide dynamic range. So the best description is that SVC provides variable reactive power through thyristor-controlled reactors and capacitors with a slower, voltage-dependent response, while STATCOM uses voltage-source converters with fast, bidirectional reactive power support and independent voltage control.

Reactive power support and how quickly devices respond to changes are the key ideas here. An SVC uses thyristor-controlled reactors and capacitor banks to vary the reactive power exchanged with the grid. The amount of VARs it can inject or absorb is adjusted by changing the firing of the thyristors and the network’s impedance, so its response is relatively slower and tied to the current system voltage. In other words, its effectiveness depends on the bus voltage and the configured reactor/capacitor elements, giving a more voltage-dependent, slower response.

A STATCOM, on the other hand, uses a voltage-source converter to produce a controllable output voltage that can inject or absorb reactive power rapidly in both directions. Because it modulates its output as a voltage source, it can regulate the connection-point voltage independently and respond much faster to disturbances, delivering bidirectional reactive power support with a wide dynamic range.

So the best description is that SVC provides variable reactive power through thyristor-controlled reactors and capacitors with a slower, voltage-dependent response, while STATCOM uses voltage-source converters with fast, bidirectional reactive power support and independent voltage control.