Power System Flexibility Assessment Method for Matching Supply and Demand with Flexibility

In recent years, the proportion of renewable energy, mainly wind power and photovoltaic, in the power system has been increasing, alleviating the environmental crisis and the problem of poor energy utilization. However, at the same time, the power system is increasingly affected by uncertainty factors, bringing many negative effects to the power system safety and reliability, etc. The fundamental reason is the lack of flexibility of the power system. In this paper, we first analyze the uncertainty of new energy output on the demand side of power system flexibility and the impact of error in load forecasting, and reflect the demand for power system flexibility through net load curve inscription. Then, this paper proposes four power system flexibility evaluation indexes starting from the basic parameters of the power system power supply side generating units. In order to better evaluate the matching degree between available flexibility resources and flexibility demand in the system, this paper further proposes a flexibility supply and demand matching index that takes into account flexibility demand and supply. Finally, the flexibility evaluation indicators were calculated and analyzed using actual operational data from a region in China to verify the validity of the evaluation indicators.