Quantitative evaluation method for inertia support capability of hydro-wind-solar base with consideration of operation mode difference

Abstract

[Objective] With the advancement of integrated development models for hydro-wind-solar clean energy bases, key challenges have emerged regarding how to achieve optimal dispatch under hydro-wind-solar coupling and how to evaluate the stability support capability provided by hydropower units. To address these issues, this study aims to explore the stability support performance of such bases under different dispatch modes and to realize optimal scheduling under large-scale renewable energy integration. A grid-connected optimal scheduling model for hydro-wind-solar clean energy bases is established, along with a quantitative assessment method for inertia support capability. [Methods] Two dispatching modes for the hydro-wind-solar integrated base are defined: large coupling and small coupling. Optimization models for both modes are constructed with the objective of maximizing the consumption of wind and solar energy. Based on the equivalent inertia constant method, quantitative evaluation indicators for the system's inertia support capability are proposed. These indicators are further used to analyze the impact of various wind-to-solar ratios, hydropower capacities, and operation modes on the system's equivalent inertia. [Results] The results show that under the large coupling mode, system frequency security is more vulnerable, with periods of inertia deficiency identified. Moreover, photovoltaic generation uncertainty exerts a greater influence on hydropower scheduling than wind power, leading to an increased number of operating hydropower units. However, this also enhances the system's equivalent inertia. Additionally, the wind-solar ratio has a more pronounced impact on the scheduling result under the small coupling mode than under the large coupling mode. [Conclusion] Under the large coupling mode, the overall inertia support capacity of the base is superior to that under the small coupling mode, providing more spinning reserves and better supporting the stable operation of the power system.

Keywords

hydro-wind-solar coupling / clean energy integrated base / optimal dispatch / system equivalent inertia / stability support