Multi-objective heuristic guide vane closure scheme optimisation of hydroturbine generating unit

Abstract

Guide vane closure scheme (GVCS) optimisation in hydroturbine generating unit (HTGU) under extreme conditions isone of the most important issues in hydropower plant design and operation. It is a kind of multiobjective constrained optimisationproblem that contains the coordination of hydraulic and mechanical dynamic processes of many system states. In such aproblem, the traditional optimisation objectives often include the control of the rotational speed of the HTGU and thesuppression of the fluctuation amplitudes of the hydraulic pressure at different locations. In order to improve the overall controlperformances in load rejection process, an improved multi-objective two-archive evolutionary algorithm (TAEA) is put forward forGVCS with chaotic operators. The TAEA-based multi-objective optimisation carefully takes the multiple objective functions andthe relevant constraint treatments including the limits on rotational speed peak, speed fluctuations, surge tank water levels,speed governor movement and hydraulic pressure oscillations into consideration. Simulation experiments of a real hydroturbineunit under load rejection condition are conducted with the proposed optimisation scheme and comparative methods. The resultsindicate that TAEA algorithm can achieve better overall performances and contribute to the operational stability of HTGU.