Dynamic surge arrester protection performance on high voltage systems using EMTP

Insulation co-ordination requires accurate prediction of the overvoltages at different points in the substation resulting from a lightning strike outside the substation from the point of view of equipment protection. For that purpose, one of the most important aspects is to consider the dynamic characteristics of metal-oxide surge arresters. Among several models, proposed in the literature, the modified IEEE recommended model is chosen. This dynamic model is used to evaluate lightning overvoltage protection in a complete three-phase scheme of an operational 220 kV substation (El-Hassi, Algeria). The effect of metal oxide surge arrester connections are also taken into account. Lightning overvoltage is generated by back-flashovers on physical multi-conductor model of real lines. The resulting overvoltages shapes and magnitudes in several basic points in the substation (line input, bus and power transformer) are computed. The simulations are performed with the Alternative Transients Program (ATP) version of Electromagnetic Transient Program (EMTP).