Study on Comparison of Power Losses Between UPQC and UPQC-DG

In the era of modern power distribution network, the motivation to use green and clean energy resources for fulfilling the need of energy demand is gaining abruptly. This has enhanced the use of power electronics-based conversion devices leading to deterioration of power quality in the power distribution network. Several compensating custom devices, such as static compensators (STATCOMs), dynamic voltage restorers (DVRs), and unified power quality conditioner (UPQC), etc., have been developed in recent decades. UPQC consists of shunt active power filter (APF) and series APF connected in back-to-back fashion with a shared DC-link. In the case of UPQC-DG, a distributed generator (DG) is also connected at the DC-link. In the existing literature available, UPQC integrated with DG is found to be a promising topology which can simultaneously compensate for power quality issues and integrate DG into the grid. Its functionality and performances have been presented by many researchers, but a detailed investigation on its power losses is missing. This article presents a detailed comparison of conventional UPQC, UPQC-DG, and UPQC-independent DG (UPQC-IDG) in terms of their respective power losses and further enhances the criteria for selecting the best possible configuration to be used practically based on requirements and economical viability. In this executed work, the power losses are compared among UPQC, UPQC-DG, and UPQC-IDG for different steady-state and dynamic operating conditions. The power losses in all configurations are inclusive of conduction losses, filtering losses, and switching losses, found using simulation and empirical studies. The comparative study is based on computer simulations performed in MATLAB/Simulink and real-time simulation using Opal-RT.