Small Microgrid stability and performance analysis in isolated island

Abstract

A generalized model of a Microgrid in an island mode is proposed for assessing the system power and frequency performances. This Microgrid (MG) includes a diesel backup generator along with a number of Distributed Energy Resources (DES): Wind Turbine Generator (WTG), Photovoltaic System (PV), Fly- Wheel Energy Storage system (FESS), and Battery Energy Storage System (BESS). Controlling the frequency deviation is posing a great challenge in stand-alone mode due to the mismatch between load demand and generation. Five different study cases were modelled in Matlab to investigate the performance and stability of the power system. Furthermore, two PD Fuzzy logic control plus Integral (PDFLC+I) act as supplementary controller were incorporated locally with diesel and storage elements in order to improve the robustness and safety of the system. Fuzzy rule and integral parameters were chosen to achieve fast response and small power and frequency deviation throughout step change in load profile. Classical PID controller was introduced for comparison purposes. The potential of using responsive charging electric vehicles (EVs) under three scenarios as a form of primary response was investigated. Simulation results showed that the decentralized controller eliminates the fluctuation effect of the wind turbine and stabilizes the system frequency. EVs can play important role in system primary frequency response.