Dynamic simulation and comparative study of custom power devices in distribution feeders for power quality improvement

Abstract

In the distribution side of electrical power systems, especially in industries, the non-linear and sensitive loads are increasing day by day, due to which the power quality (PQ) is degrading. The main PQ issues are voltage sags, reactive power imbalance, and harmonics, which are primarily addressed by advanced power electronic devices known as custom power devices (CPDs). However, selecting an appropriate device remains challenging because most existing studies evaluate these CPDs independently under various operating conditions. To address these challenges, a unified comprehensive analysis of various CPDs has been presented in this paper, i.e. distribution static compensator (D-STATCOM), dynamic voltage restorer (DVR) and unified PQ conditioner (UPQC), by means of various simulation results using MATLAB Simulink. The voltage and current responses were examined under various transient disturbances in a high-voltage distribution feeder model. The D-STATCOM provided a fast reactive power response, while the DVR effectively mitigated the voltage sag. However, the harmonics were effectively mitigated with an UPQC, and the voltage was restored to normal limits. The performance of all three devices has been analysed and compared using a radar-based analysis index based on certain parameters. The proposed results for the two CPDs, i.e. D-STATCOM and DVR, have been experimentally validated to demonstrate the practical usefulness of the planned control strategies under real-time conditions. This study will help select a specific CPD for different power-quality applications in industry.