An Extensive Study on Optimization and Control Techniques for Power Quality Improvement

With the rapid emergence of microgrids in existing power system and stochastic nature of distributed generations leads to several power quality problems including voltage variations, frequency fluctuation, harmonics etc. Power quality is an unavoidable, unwanted phenomenon present in the power system which can not be eliminated totally but can be reduced by applying some mitigation techniques. In order to address this issue several researchers investigated multiple control techniques in alliance with optimization methods. This review paper basically deals with the overview of optimization and control techniques utilized so as to improve the system power quality. Effectiveness and robustness of these optimization techniques is discussed in the paper.

I. Introduction

Due to the increase in energy demand and decomposition of fossil fuels, researchers has put several efforts to find out alternates of power generating sources. Non conventional sources like solar, wind etc. came out as one of the supportive substitute sources of power generation. But power generated from these sources are highly random, unreliable and stochastic in nature [1]. Microgrid (MG) is a cluster of loads and micro sources efficient to distribute power to the local region as well as with grid connection shown in Fig. 1. Power generation through renewable energy sources are intermittent in nature, thus to ensure uninterrupted power supply energy storage systems are incorporated in the system. MG are leading as intelligent, flexible and distributed generation sources and operates in conjunction with utility grid or in autonomous mode [2]. Operation of microgrids in any of these modes is either intentional or sometimes due to operating conditions of power systems. Controlling grid operation as per the standard is one of the challenge in developing countries [3]. Incorporation of non-conventional power sources in the electric grid, intermittent nature of renewable source leads to irregular power generation, transmission in local areas. Power system stability and power quality should be refined by mitigating the issues arises because of voltage fluctuations and frequency deviation. In microgrids, deviation in frequency and voltage is caused due to the transition from normal mode to islanded mode. In islanding mode, control approach should be required for both generation and distribution side [4].