Flexibility Evaluation Method of Power System Considering the Impact of Multi-Energy Coupling

With the increasing penetration of renewable energy resources, the problems of energy waste and economic decline are exacerbated in the power system, especially on accommodating anti-peak-regulation of wind power. To make the dispatch of flexible resources more reasonable, a flexibility evaluation structure is established in this paper, which can guide operation strategy and effectively increase wind power consumption. Firstly, by analyzing the working principle and operating characteristics of various flexible resources, such as each unit, energy storage, energy coupling unit and adjustable load, the flexibility boundary restrictions are quantified. Secondly, the power-gas-heat integrated systems (PGHIS) model is established, and the system available flexibility indexes are proposed to quantitatively evaluate the system flexibility from multiple aspects of sources, storages and loads. Furthermore, the flexibility provided by integrating other energy systems and flexible resources at different dispatching times can be calculated, which further releases the dispatching pressure of the power system. Finally, the case study is verified on the modified IEEE39-NGS20-HS4 test system. The proposed method can effectively assess flexibility and optimize operation of power system with multi-energy coupling.