AN ALGORITHM FOR FREQUENCY RELAYING BASED ON LEAST ABSOLUTE VALUE APPROXIMATIONS

This paper describes a new algorithm for measuring the frequency and the rate of change of frequency at a power system bus for frequency relaying applications. The new algorithm is based on the least absolute value approximation. The algorithm uses digitized samples of the voltage at the relay location to estimate the frequency and the rate of change of frequency of the power system. Effects of sampling rate, sample window size and time reference on the performance of the algorithm are discussed. Two models for the frequency estimation, namely, the constant frequency model and the variable frequency model, are used. Samples for test results are reported in this paper, where we compare the newly proposed algorithm and the least squares (LS) technique used earlier in the literature together with the linear programming (LP) algorithm. © 1990.