Frequency estimation of low-voltage distribution systems in transient processes

A fast algorithm for tracking the frequency of low-voltage distribution systems in transient processes is presented in this paper. A RC circuit is taken into consideration, and the current signal of transient process in the RC circuit is used to estimate the frequency of distribution systems. The transient current signal is proposed to be a sinusoidal signal with an additional decreasing magnitude in the form of exponential functions. Employing central numerical differentiation of 7 sampling points and Lagrange interpolation, the frequency of low-voltage distribution systems in transient process is estimated at an accuracy of 99.99% in half cycle. The simulation results of an example show better dynamic features of the proposed algorithm, the simulation is carried out in Matlab software and a digital control system.