Transmission lines both generate and absorb reactive power. Since the transmitted load varies considerably from one hour to another, this cause the reactive power balance of the line to vary as well. In order to continuously control dynamic power swings under various system conditions a Static VAR Compensator (SVC) is used.

The main reasons for incorporating SVC in transmission and distribution systems are:

  • Stabilizing voltage in weak systems
  • Reducing transmission losses
  • Increasing the transmission capacity, thus delaying the need for new lines
  • Increasing stability for transient disturbances
  • Increasing damping of small disturbances
  • Improving voltage control and stability
  • Damping power swings