Flexibility evaluation of distribution network with high penetration of variable generations

In order to adapt requirements of accessing high penetration of renewable energy resources and meet dynamic energy balance of system in condition with strong uncertainty, it is necessary to evaluate and enhance the operational flexibility of the distribution network. A flexibility evaluation method aimed to system regulation requirements is proposed to quantitatively evaluate operational flexibility of a distribution network with high proportion of variable generations. Firstly, the operational characteristics of flexible resources are estimated based on statistical analysis of network parameters and operating data, and the time scale of evaluation is fixed according to response time of flexible resource. Then the bi-directional flexibility adjustment requirements are separated and the double-layer index system is constructed. Based on the Monte Carlo simulation algorithm and the optimal economic scheduling model, the flexibility index calculation method is proposed. At last, the evaluation result is obtained by using calculated objective weight, and the IEEE 33 node distribution network is used as the reference grid to analyze the case. This method could evaluate the flexibility of distribution network from the aspects of tolerable fluctuation ability, renewable energy consumption capacity, energy balance ability and power regulation ability. The result shows that the proposed method is scientific and reasonable, which can be used for providing reference and guidance for planning and operation of distribution network.