A genetic based filter for removal of DC-OFFSET in current and voltage signals

Protective relays must filter their inputs to reject undesirable quantities and retain signal quantities of interest. It is very important to perform this job accurate and fast. This paper presents a new method for filtering the undesirable components such as d.c and harmonic components associated with the fundamental system signals. The filter is based on genetic algorithms (GAs) optimization techniques. The filtering algorithm has many advantages over some other classical methods. It can be used as dynamic on-line filter without the need of parameters readjusting as in the case of classic filters. The proposed filter is tested using different signals. Effects of number of samples and sampling window size are discussed. Effects of GAs parameters and operators, such as population size, crossover, mutation probabilities, niching and fitness functions are also studied. Results are reported and discussed.