Evaluating Transmission Network Flexibility Considering Uncertainties

The high-volatility output of intermittent renewable energy has a negative impact on the supply and demand balance of the system, making the system inflexible and difficult to absorb large-scale renewable energy. To this end, this paper considers the unpredictability of renewable energy and builds a typical scenario and probability of its output based on the scenario analysis method. On this basis, for the problems of system absorption and dynamic energy balance, a transmission network flexibility evaluation method is proposed from the four flexibility requirements of fluctuation capacity of new energy output, new energy consumption capacity, charging residual capacity and available transmission capacity. This method considers the potential impact of network architecture and line congestion on flexible resource calls. Through the evaluation of the improved IEEE 39 node system, the values of various indicators in the economic operation mode are obtained. The capacity of the new energy consumption and the line blocking rate prove the rationality of the proposed indicators. The mentioned indicators are helpful for planning the location of renewable energy power plants, configuring energy storage devices and finding branches with insufficient flexibility, and prioritizing expansion and upgrading in a targeted manner.