Transient AC/DC simulator and field tests of the closed loop control of the Pelham SVCs

Two static VAr compensators, SVCs, have been installed at the Pelham substation near London (UK) and were put into commercial operation in the summer of 1992. Both SVCs incorporate a TCR/TSC combination to give nominal ratings of -75 MVAr to +150 MVAr and are connected to the National Grid 400 kV system. Before the commissioning period, a phase of extensive testing and analysis of the digital closed loop control system was performed. This work was carried out using the original control hardware and software in conjunction with a real time transient AC/DC simulator (TNA). The results of this work were checked against field tests performed during the commissioning period. The parallel and independent operation of both SVCs at the same system node received special consideration. This paper gives an overview of the closed loop control and presents a spectrum of simulator and field test results of the SVCs´ operation