Research On Risk Assessment Of Distribution Network With Microgrids

The distribution network which is intended for users can be regarded as the link between the grid and the load. With the application of the distributed power generation and the microgrid technology,the risk level of the distribution network configurated with microgrid has become an important research direction in recent years.The purpose of risk assessment research of the distribution network with microgrid is to guarantee the security of users’power supply, and to obtain the possibility of power failure and its damage to users and the whole system.To conduct a risk assessment of a power system,both the probability and the consequence of the failure should be took into consideration.For failure probability, this paper uses the improved state sampling method to obtain the failure sequences and calculate the probability of the sequences.For failure consequence, this paper uses the method of minimum time segmentation to calculate the outage time and the energy not supplied.This article defines two types of risk indicators which can evaluate the system’s risk of power-loss and economy-loss.With the development of distributed power supply, the study of risk assessment methods and the risk level of distribution network with microgrid has practical significance.After discussing the risk assessment method of distribution network,this paper proposes the improvement of the method which classifies the operating states of the microgrid firstly. The output of distributed energy resource is discribed by real-time output model,and the battery is discribed by two-pool model which considers the charge and discharge constraints.The power balance of microgrid is analyzed in every minimum time segmentation.Through the calculating of the IEEE RBTS BUS6 and the system network of an island in Shandong province,the comparison of the risk level of different microgrid configuration scheme is carried out in this paper.