Dual-Tree Complex Wavelet Transform-Based Control Algorithm for Power Quality Improvement in a Distribution System

This paper presents a dual tree-complex wavelet transform-based control algorithm for a distribution static compensator (DSTATCOM) to improve the power quality (PQ) in a distribution system. PQ disturbances like harmonics and starting as well as ending of unbalancing in all phase load currents are also assessed simultaneously. The distorted load current of each phase is decomposed into various frequency levels with this technique to extract respective line frequency component for the estimation of the reference active power component. The deviations of respective sensed load currents from these estimated reference components are used to generate the reference currents for the control of voltage source converter used as DSTATCOM. Simulated performance of DSTATCOM is presented at varying load conditions. The proposed control algorithm is also validated experimentally on a laboratory prototype of DSTATCOM. The total harmonic distortion (THD) of supply current is obtained below 5 percent with unity power factor under different load conditions which is satisfactory as per IEEE-519 standard.