Evaluation Method of Distributed Generation Carrying Capacity for County Power Distribution System

In this paper, aiming at the problem of carrying capacity evaluation caused by the large-scale access of distributed photovoltaic in county distribution system, two kinds of methods for evaluating the carrying capacity of distributed power supply for county distribution system are proposed. Firstly, based on the structural characteristics of the county distribution network, a differentiated carrying capacity calculation framework is proposed, and a time-series power flow simulation model considering energy storage configuration is constructed. By decoupling the constraints of multi-voltage level equipment, an energy storage operation model considering charge-discharge efficiency and state of charge constraints is constructed for the characteristics of the energy storage system. The improved particle swarm optimization algorithm is used to achieve multi-objective optimization solution. This method can evaluate the photovoltaic carrying capacity of the county as a whole and each voltage level equipment hierarchically. Secondly, considering the optimization of new energy consumption, a ‘source-network-storage-load’ collaborative optimization model is innovatively constructed, and a two-layer optimization architecture of optical storage microgrid is proposed. The upper layer establishes a day-ahead scheduling model with the goal of optimal economy, and the lower layer designs a dynamic adjustment mechanism of tie-line power. Finally, taking Gaoyang County of Hebei Province as a typical case to carry out empirical research.