Improvement in Power Quality using Hybrid Power Filters based on RLS Algorithm

Abstract

In industrial and utility power system it has been observed that harmonics build a major role in reducing the quality of power. These harmonics are caused because of increasingly utilize of nonlinear loads connected to the power system. In this context, active power filters play a very significant role for improvement in power quality. Moreover, at transmission ground, there is a high requirement to control reactive power and voltage stability. Conventionally, passive and active filters (shunt and series filters) were used for the development of power quality. But, they suffered from the issues like resonance, fixed compensation, and other PQ problems. Therefore, to minimize these issues, a hybrid combination of filters using passive and active filters is designed. In this paper, a comparative study of two hybrid model of HAPF is done based on current control techniques like d-q and p-q theory under different operating conditions. These results are again compared with a new estimation technique proposed in this paper well known called as recursive least square (RLS) harmonic estimation technique. The amplitude and phase angle of both the fundamental and harmonic currents are estimated with the proposed RLS technique. At the point of common coupling (PCC) the signal which is composed with harmonics is estimated with and without HAPF. Finally, it is analysed from the observation that the load current and supply current is improved significantly with a decrease of total harmonic distortion (THD) under different operating scenarios.