PV and Wind Distributed Generation System Power Quality Improvement Using Modular UPQC

Abstract

Today reliability and power quality are the two terms which influence the economic growth of any country. The current variations are one such power quality issue which affects power system. The root cause of these current variations as harmonics is due to the intensified usage of nonlinear loads. Active power conditioners can reduce current harmonics (SAPFs, SEAPFs, UPQCs, IPQCs). To be more specific, SAPF consists of a DC synchronizing Capacitor and a voltage source converter. In voltage source converters, the power semiconductor devices are switched using a Hysteresis Band Current Controller (HBCC). Series reactive current (SRC) injection is used for voltage compensation, and a proposal for using power quality (PQ) theory to produce reference currents to inject at the site of coupling for current reduction is made. By using pulse-width modulation and hysteresis as switching mechanisms, the UPQC will function in the presence of various disturbances, including phase-to-ground faults, non-linear loads on the grid side, and non-linear loads in parallel with the sensitive load. The functioning of the Unified Power Quality Controller (UPQC) is dependent on the voltage available across the capacitor in the dc connection; nevertheless, it is capable of compensating for all these issues. With a steady voltage applied to the capacitor, it performs well. Here an attempt is made to combine solar and wind generation stations with modular UPQC to enhance power quality issues of concern. Simulations were performed in MATLAB/SIMULINK.