ANALYSIS OF PROTECTION MEASURES ON EQUIPMENT OF GIS FOR VERY FAST TRANSIENT OVER-VOLTAGES

A.Raghu Ram, P.Swaraj

Abstract: Gas Insulated Substations (GIS) have found a broad range of applications in power systems because of their high reliability, easy maintenance, small ground space requirements etc. In a Gas insulated substations, the operation of disconnector switches and circuit breakers can cause Very Fast Transient Overvoltages (VFTOs), which will bring an instantaneous change in voltage with a very short rise time and it is normally followed by oscillation having high frequencies. For designing the insulation level of a substation, it is essential to know the maximum value of VFTO. Fast operating disconnector switches are usually used to reduce time of the breakdown; however, it cannot eliminate fully the effect of the VFTO. Very Fast Transient Overvoltages caused by disconnector switch operation of 1000 kv GIS is simulated and calculated in this paper using MATLAB. The various protection measures on equipment of GIS have been compared and analyzed by adding ferrite rings, opening and closing of resistor, metal oxide arrester and R-C absorber.

Keywords: Gas Insulated Substation, Very Fast Transient Overvoltage’s, Matlab/Simulink, Disconnector switch.

DOI: https://doi.org/10.15623/ijret.2012.0102018