Research Of Evaluating Power Supply Capability Of Active Distribution Network

In recent years, with the promotion of energy security and environment protection pressure, renewable energy power generation has experienced a rapid development worldwide. More and more distributed generations using renewable energy have been embedded into distribution network, which puts forward new problems and challenges for the planning and operation of distribution network.There can be strong randomness and uncertainty in the output of distributed generation using intermittent renewable energy, such as wind and solar. The volatility of power generation can be obscured by the fluctuation of load when the distribution system has a low permeability. Therefore traditionally only the power value of distributed generation using intermittent renewable energy is considered. However, the load supplied by the traditional distribution network will be changed greatly as the capacity and quantity of distributed generations embedded into distribution network increase fast, and more and more load is elimination direct on the user side. Distribution system can be able to cope with a larger load growth, thus delaying the needs of upgrading the distribution network. Therefore, scientific evaluation of the capacity value of distributed generation as well as power supply capability of active distribution network has great importance.This paper establishes the concept of power supply capability of active distribution network, and puts forward the evaluation method for power supply capability of active distribution network. Firstly, in view of the traditional methods for evaluating power supply capability of distribution network which ignore the matching relationship in time sequence between the power source and the load, put forward new ideas of evaluation power supply capability of active distribution network, namely the load supply capability of active distribution system under certain reliability requirements. Secondly, based on Monte Carlo simulation method, an assessment method of active distribution network adequacy is established, then an heuristic method of load adjustment based on the adequacy evaluation is put forward to analyze the load transfer capability of distribution network by changing the network structure and capacity value of distributed generation, which form the evaluation method of power supply capability of active distribution network. Numerical examples are given to analyze the effects of reliability levels, different load types, distributed power allocation and other factors on the power supply capability of active distribution network, which can provide a new idea and method for guiding the planning and operation of distribution system and optimal allocation of distributed generation.