Research and implementation of frequency control strategy of islanded microgrids rich in grid-connected small hydropower

Abstract

Due to the weak network architecture of mountainous power grid rich in grid-connected small hydropower, once the small hydropower units operate independently as a network when the upper power grid fails and loses power, the reliability of the power supply could be effectively improved. To cope with the problem of insufficient frequency regulation capacity of small hydropower units and the large risk of separation fault, this paper proposes a piecewise variable coefficient PID control strategy which improves the speed regulation control strategy of hydropower units, and a joint frequency regulation strategy of hydropower energy storage is designed to optimize the system operation state. Based on the MATLAB simulation platform, a hydropower energy storage microgrid model of mountainous power grid was built to verify the effectiveness of the segmented variable parameter control strategy. Using the proposed control strategy, the hydropower intelligent control terminal was developed and put into application in a certain area of Guangdong. Through simulation analysis and engineering applications, the practicality of the application of device engineering is verified to have good application and promotion value for a multi-hydropower mountainous power grid.