SVC: A static VAR compensator (SVC) is a set of electrical devices for providing fast-acting reactive power on high-voltage electricity transmission networks.

Statcom: A Stati synchronous COMpensator (STATCOM) is a fast-acting device capable of providing or absorbing reactive current and thereby regulating the voltage at the point of connection to a power grid.

Advantages of SVC

1. SVCcontrol voltage directly.
2. SVC control temporary overvoltages rapidly.

Advantages of Series Compensation

1. Series capacitors are inherently self regulating and a control system is not
2. For the same performance, series capacitors are often less costly than SVCs and losses are very low.
3. For voltage stability, series capacitors lower the critical or collapse
4. Series capacitors possess adequate time-overload capability.
5. Series capacitors and switched series capacitors can be used to control loading of paralled lines to minimise active and reactive losses.