Intelligent Controller Technique for Reactive Power Control in an Isloated Micro-Grid

Abstract

This paper proposes a hybrid based approach using particle swarm optimization (PSO) and imperialist competitive algorithm (ICA) based robust controllers for the voltage fluctuations in a wind diesel based micro-grid system. The system comprises of a wind energy conversion system having a permanent magnet induction generator (PMIG) and a diesel engine set with a synchronous generator (SG) for power generations. The gap between generated and consumed reactive power in the system causes voltage deviations, at generator terminals. These oscillations further reduce the quality and stability of the power supply. An automatic voltage regulator (AVR) and a static synchronous compensator (STATCOM) are used to suppress these voltage deviations. The AVR is used for keeping terminal voltage constant for the synchronous generator while the STATCOM is used as a reactive power compensator. Both AVR and STATCOM are using proportional and integral (PI) controllers with single input. A normalized co-prime factorization is used to represent the possible unstructured uncertainties in the system like variation of system parameters and generating and loading conditions. The performance and robust stability conditions of the control system are made as the optimization problem. The optimization problem is based on the <tex xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">$H$</tex> loop shaping. A hybrid PSO-ICA algorithm is implemented to solve this optimization problem and to achieve PI control parameters of AVR and STATCOM simultaneously. To show the efficiency of the proposed controllers, the performance of the proposed controller is compared with the performance of the conventional controller, and with ICA, PSO and whale optimization algorithm (WOA) based PI controllers for the same system. The dynamic responses of the system for four different small-disturbance case studies have also been carried out in a MATLAB environment.