Wide area backup protection scheme for distance relays considering the uncertainty of network protection

Abstract

Although local protection methods can perform well at speed, in a real network where network uncertainties are unavoidable, these methods may result in inaccurate performance. Therefore, the use of other methods, such as wide area protection, can lead to more accurate results because of using comprehensive information via telecommunication links. In this paper, a wide area protection algorithm is presented to cover the mal-operation of relays due to the network uncertainties. In this method, an objective function is defined based on the performance status of various zones of distance relays, the values of which will be different for each line. Depending on the position of each relay on the transmission line, weighting factors for objective function are determined based on the optimization algorithm and taking into account the possible uncertainties of the power grid. The proposed method has been implemented on IEEE 9-bus system and has proved high detection precision and performance accuracy.