Frequency Estimation on Power System Using Recursive-Least-Squares Approach

An approach based on recursive-least-squares (RLS) algorithm is applied to the frequency estimation of the instantaneous power system. The three-phase voltage signal is transformed to a complex form which is easy to be handled by the proposed approach. When compared with other algorithms, the RLS algorithm is more suitable for online frequency estimation due to its rapid convergence rate. An arccosine function-free technique is applied to the frequency estimation approach to reduce computational complexity. The effect of noise, convergence rate, harmonics and dynamic frequency variation on the performance of the approach is discussed.