Prevention of sympathetic tripping phenomena on power system by fault level management

Abstract

Many utilities have plans for interconnection of their grids for purpose of flexibility of supply and energy exchanges. And with the advent of regional, national and international grid operations a number of technical challenges also are faced. One of the problems of late that has to be tackled in the day to day operations, is fault levels management. Interconnecting of huge generating stations results in increased fault levels, at times beyond the capacity of the existing switch gears. This increased fault level will cause increase of voltage sags of magnitudes that will initiate the sympathetic tripping phenomena of the distribution feeders and at times the transmission lines. An effort is made in this paper to explain the "sympathetic tripping phenomena", the causes, and its 'after effects' on a power system and suggest solutions to mitigate the problem of the power sector .The paper focuses on the previous solutions to the problem and suggests new approach to deal with. Model / simulation of different aspects are analyzed and discussed in detail. Recommendations / suggestions are made in the paper to help the inhibition of this sympathetic tripping phenomena and with the use of techniques to keep the existing system equipment, without the need of replacements and still keep the fault levels at or near the previous level, as well to prevent sympathetic tripping phenomena in the power system.