SVC control retrofit - example Clapham

More than 50000 MVars of controlled reactive power are installed worldwide in transmission systems since the early 70´s. Many of them are faced to reach the expected end of their designed life-time and need refurbishment of various components. Some of them have already been upgraded and renewed in various aspects which are discussed briefly below. The paper describes the control retrofit of the Clapham SVC which was necessary mainly due to future lack of control system components. The new digital control should be based on the state of the art technology on one side and should also include a new control feature on the other side. Test and procedures necessary for the exchange and implementation are described.