Transmission systems are subject to daily or seasonal load variations. Variable shunt reactors allow customers to continuously adjust the compensation, as loads vary over time.
They make switching in and out of fixed-rating reactors unnecessary, which eliminates harmful voltage steps. The variable reactor can always be adopted to the need, both in today’s operation and in the future grid. In addition, VSR can interact with other systems such as static var compensators (SVCs) and high-votlage direct current (HVDC) links in order to optimize the system operation and maximize dynamic capacity during failures.
Variable shunt reactors are therefore economical means to improve voltage stability and power quality under time-varying load conditions.
VSRs have become well established and several are in operation in Europe and North America.