Evaluating Risk Of Distribution System Containing Distributed Generation

Distribution system is a link by which users are connected with the whole power system. Its risk level is concerned by power supply companies and users, so it is a very important research direction. Study of distribution system risk level aims to provide safe and reliable power supply, and to show the adverse impact on users by power system failure.Study of distribution system risk assessment is carried out through power system failure probability and failure consequences. For failure probability, it can be obtained from the calculation of reliability index. Failure consequences severity index is defined, and the failure consequences of power system are evaluated by energy loss and user loss. Finally, systemic risk index can be obtained by system failure probability and failure severity index, and it can be used to characterize the system's risk level. For systems of different area or different planning programs of the same area, the risk index can be used to compare their risk level.Along with the development of distributed generation, distributed generation has been connected to power system widely. So it is important to study distributed system risk level containing DG. In this paper, the distribution system containing DG is studied based on the study of distributed system risk level. Based on the actual application, DG is considered as a random generation, and the concept of "islanding probability" is introduced. On this basis, risk index of the distribution power system containing DG is analyzed. The effect of DG on distribution system risk index is analyzed and compared through practical examples.Finally, a variety of factors affecting distribution system risk level are analyzed. From the failure source and risk management level points of view, a series of measures are proposed to improve risk level of distribution system, which can provide a reference to the power supply company.