STUDY OF THE INFLUENCE OF THE POSITION OF ZNO SURGE-PROTECTIVE DEVICES ON THEIR PERFORMANCE IN A DISTRIBUTION NETWORK

Installation of one or more surge-protective devices in a distribution network, necessitate to ensure that these devices achieve a reliable protection against surges impinging from the utility supply as well as internally generated surges. Zinc oxide varistors are solide state suppressors widely applied to limit voltage surges in the electrical networks. These devices are increasingly becoming as a substitute for silicon carbide valve blocks in surge arresters. This material with non-linearity characteristics far superior to silicon carbide, can be used to manufacture arresters which do not employ series gaps. The purpose of this paper is to study the operation of these arresters in distribution networks and to optimize their position to have the best protection. We have done several experiments on an experimental network and have also simulated the distribution network by means of the EMTP software. By changing the position of the surge-protective device in the network, we have studied the influence of its location on its performance and life time.