An optimization decision-making framework for the optimal operation strategy of pumped storage hydropower system under extreme conditions

Abstract

Frequent condition changes of pumped storage hydropower system make it inclined to stuck in extreme energy conversion process, posing great threats to steady operation. This paper proposes a comprehensive framework to specify optimal operation strategy for admirable transient process under extreme conditions. Three principles consist the framework, the refined model of successive load rejection is primarily established, which accedes time-varying and strong nonlinear characteristics and accurately grasps the trait of successive load rejection. Furthermore, an improved genetic algorithm with excellent capabilities of exploration and exploitation is proposed, multiple control schemes are investigated with variations of control parameters. Whereafter, a hierarchical decision-making structure of operation strategy considering qualitative and quantitative indicators is firstly constructed, the intuitionistic fuzzy analytic hierarchy process is innovatively introduced to specify optimal scheme. The originality of the framework lies in comprehensiveness and completeness. Multiple complexities of refined model, multiple schemes of optimization strategy, multiple determinants of decision-making are fully considered. Testifying to real cases, the optimal strategy can effectively improve water pressure indicators of volute and draft tube by at most 64.4 m and 32.52 m. These results highlight the effectiveness and availability of the proposed framework for sustaining safe operation simultaneously reducing investments of pumped storage hydropower systems.