A universal stability quantification method for grid-connected hydropower plant considering FOPI controller and complex nonlinear characteristics based on improved GWO

Abstract

The stable operation of the hydropower plant is an important guarantee for power delivery quality and the security of power grids. Nevertheless, the current stability analysis is only focused on simplified models, leading to an inaccuracy result. Therefore, a novel nonlinear model of the grid-connected hydropower plant system with fractional order PI controller considering nonlinear characteristics is taken as the research object. Then, a new universal stability quantification method for complex nonlinear systems is proposed to overcome the application limitations of traditional methods. Finally, the stability and parameter sensitivity of the system are investigated. The results demonstrate that the proposed method is highly accurate and robust, whose errors fall within the range of [-0.0025,0.0005]. The results show that the governor nonlinearity and integral order of fractional order PI controller have an obvious negative influence on the stability of the hydropower plant.