Voltage profile enhancement in low voltage 11/0.4 kV electric power distribution network using dynamic voltage restorer under three phase balance load

Abstract

With the global trend of restructuring in electricity market, providing affordable, reliable and quality electric power by service providers to customers the end users of electric energy are of immerse concern. Several initiatives have been taken by utilities to improve power quality in low voltage electric power distribution network but the inadequate operation/performance of the conventional compensation devices to mitigate the poor power quality problems have prompted the use of custom power device such as the dynamic voltage restorer (DVR). Dynamic voltage restorer (DVR) is an advanced power electronics based compensation device which is series connected to the distribution network through boosting transformers. DVR aimed at improving the voltage profile, enhancing the reliability and good quality of power flows in low voltage electric power distribution networks. The DVR is a highly efficient device, the principle is based on the voltage source inverter (VSI) which injects the appropriate missing voltage in series with the system voltage to correct the voltage variations experienced in the distribution feeder lengths. The dependability, robustness and effectiveness of the DVR control and power scheme in respect of the response to voltage disturbances at normal mode operation of three phase balanced loads is presented using the MATLAB simulation results carried out in Power System Sim Tool box. The balance of the paper gives recommendations on effective methods for improving the voltage profile and reducing the voltage variation to an allowable standard.