Analysis of Uncertainties for the Operation and Stability of an Islanded Microgrid

摘要

The demand for energy is increasing from the development of loads which requires that the power sources should be expanded in terms of the number and output power. Therefore, the integration of Distributed Generators (DGs) including renewable energy sources (solar, wind, tidal energy, etc.), diesel generators and energy storage systems into power systems is considered to be the current development trend, and Microgrid becomes an effective solution to fulfill the mentioned demand. Microgrid can operate in grid-connected mode, islanded mode or flexibly switch between these two modes. However, renewable energy sources in Microgrid are easily affected by uncertainties from the external environment such as sun radiation, temperature, wind flow, etc., making the system stability cannot be guaranteed, especially when operating in islanded mode. Many previous studies have investigated the impact of uncertainties on the operation of Microgrid but have not really shown the significant influence of these factors in practice. This paper focuses on analyzing the influence of DGs in Islanded Microgrid, specifically: photovoltaic systems, diesel generators and energy storage systems, combining with the Maximum Power Point Tracking (MPPT) algorithm and power distribution control methods. The fluctuations and characteristics of DGs are clearly reflected in the paper. The results show that when there is a significant and sudden change from uncertainties, Islanded Microgrid easily destabilizes, affects the operation of the system and reduces power quality.