Digital computer studies and some test results for a static VAr compensator in the UK transmission network

Several SVCs of 150/-75 MVAr rating are being installed in the 400 kV transmission network in the south of England. The SVC transformer as well as the TCR, TSC and filter circuit components are subject to a variety of transient overvoltages which are limited by gapless metal oxide surge arresters. The authors describe subsequent digital studies which are used to determine the severest transient stresses to which various surge arresters could be subjected. Such studies involve investigations of lightning transients, SVC energisation and fault application/clearance events. A further set of studies involving digital analysis of the basic control system is also discussed which uses eigenvalue methods. Where comparison between analytical methods, simulator test results and site measurement has been possible, agreement is shown to be good