Investigations on the effectiveness of UPQC in distribution network with DTC drive as load

Abstract

Power quality problem is a presence of nonstandard voltage, current or frequency that results in a failure of end user equipment. With Power quality problem utility distribution networks, industrial load, sensitive load etc. are suffered. With the restructuring of power systems and with shifting trend towards distributed and dispersed generation, the issue of power quality is taking new dimensions. The concept of custom power was introduced to distribution systems for improving the system performance. Unified Power Quality Conditioner (UPQC) is a custom power device which can compensate for both voltage and current at distribution level and controls the reactive power flow at the same time. It protects the consumer at the load end from supply voltage sag, and provides unity power factor condition at the utility for different values of load power factor. In this thesis work UPQC is realized using MATLAB/SIMULINK. The model is tested for varying load conditions under normal and faulted conditions. Comparison of voltage and current level in different operating condition is done along with the comparison of Total Harmonic Distortion (THD) level with and without UPQC compensation is presented. UPQC is realized using IGBT based PWM-VSI inverter having a DC bus capacitor. A dqo transformation based PWM current controller is used to derive gating pulses for the IGBT switch. It is seen that UPQC is effective in compensating current, harmonics, reactive power and improving the power quality of the distribution system.