Ecological flow considered multi-objective storage energy operation chart optimization of large-scale mixed reservoirs

Abstract

A reservoir operation chart is effective in guiding the actual operation of reservoirs. With the development and construction of large-scale mixed reservoirs, operating reservoirs using multiple objective operations has become a hot issue. This study, therefore, improved and expanded the traditional energy storage operation chart (ESOC) model for pure cascade reservoirs based to the special relationships between hydraulics and water volume of the upstream and downstream reservoirs in a mixed reservoir system. Considering the objectives of flood control, energy generation (including power generation, guaranteed output, and assurance rate), and ecological flow, a multi-objective ESOC optimization model for large-scale mixed reservoirs is established, and the corresponding solving method for this model is proposed. Taking the Pearl river basin of China as an example, the multi-objective Pareto fronts of different minimum discharges of upstream reservoirs are obtained. According to the actual operation demands and constraints, the optimal multi-objective schemes under different assurance rates and different ecological flow satisfaction rates are extracted based on the obtained Pareto fronts. For example, if the assurance rate of power generation is required to be equal to or greater than 90% and the ecological flow, the satisfaction rate of downstream control sections is required to be equal to or greater than 0.97, the scheme is the best when the minimum discharge of upstream reservoirs is 300 m3/s, and the corresponding power generation and guaranteed output are 58.989 × 108 kWh and 439 GW, respectively. On the whole, the proposed models and related results have significance for the actual operation of large-scale mixed reservoirs.