Mitigation of Disturbances on Load Side using UPQC in an AC Microgrid

Abstract

The importance of Microgrid concept is increasing extensively and more number of microgrids will be installed at consumer premises in the coming future. The penetration of distributed generation (DG) units consisting different loads makes microgrids suffer from power quality and power control issues. Some of them are voltage stability, swells and sags, and power factor improvement which require reactive power. In particular, microgrid in islanded mode has to maintain the power balance independently of a main grid due to lack of infinite bus as generation and consumption are tightly coupled. Due to versatile loading conditions, even in grid connected mode reactive power compensation is becoming a challenging task. Hence the key objective of this paper is to investigate reactive power compensation in microgrids. In this regard, new techniques and devices for VAR compensation in the micro grid are being investigated. The device considered in this paper is Unified Power Quality Conditioner (UPQC). Initially UPQC is modeled, simulated and tested in conventional distribution power system. Later the same is incorporated into the microgrid. The microgrid is developed with two DG units, a PV generator and a wind generator to give an output voltage equal to the conventional 3 phase 4 wire distribution system. The performance of the UPQC with its control technique in providing the reactive power compensation to resolve the power quality issues in microgrid with dynamically varying load is examined.