Modeling and Simulation of UPQC with Islanding and Seamless ReconnectionTechnique for Microgrid using Fuzzy Logic

Abstract

The micro-grids are interconnection of renewableresources available at distribution side .Micro -grids can be operated in three different ways grid connected mode, autonomous mode and micro generation mode .The battery system is connected in DC link for supplying real power in the micro-grid .Quality of power supply has become an important issue with the increasing demand of DG system either connected to the conventional grid, smart grid or micro grid. Most of the pollution issues created in power systems are due to the nonlinear characteristics and fast switching of power electronic devices which introduce harmonic in the line voltage and current.To eliminate the power quality issues from the distribution system it is essential to improve the reliability of the system. The Unified Power Quality Conditioner (UPQC) is used to improve the real power by improving the quality of supply during the interconnected and islanded mode.The series part of the UPQC (APFse) is connected before the PCC and in series with the grid. The dc link can also be integrated with the storage system. An intelligent islanding detection and reconnection technique (IR) are introduced in the UPQC along with fuzzy logic as a secondary control. Hence, it is termed as UPQCµG−IR. During the interconnected and islanded mode, DG converter with storage will supply the active power only and the shunt part of the UPQC will compensate the reactive and harmonic power of the load. It also offers the DG converter to remain connected during the voltage disturbance including phase jump. The simulation was done by using MATLAB/Simulink software.