Research On Reliability Assessment Of High-Medium Voltage Level Distribution System

As a link of the end user and the generation transmission system,the distribution system is a very important part to ensure safe and reliable power supply for user.Distribution system including distribution lines,substations and other electrical facilities of different voltage levels,each link are all have important impact to the user’s power supply quality and reliability.With the growing complexity of the structure of the distribution system,higher requirements of distribution system reliability analysis method are put forward.To conduct comprehensive distribution system reliability evaluation,different voltage levels of distribution system typical connection modes and corresponding operating characteristics were need to analyze,especially the fault recovery process of multi-contact structure distribution system,and it also need to count in the coordination process of various aspects after the failure,to achieve accurately assess of reliability of the distribution power system.Therefore,to conduct in-depth studies on reliability assessment issues of multiple voltage levels distribution power system,so as to effectively guide the distribution system reliability integrated assessment,is the problems which need to be solved at this stage.How to fully and accurately assess the significance of the distribution system reliability is very important for network planning and many other aspects.For this situation,based on distribution system diagram,high-medium voltages distribution system reliability collaborative assessment and high-medium distribution system recovery research model,the research of high-medium distribution system multi-level collaborative analysis reliability assessment was carried out,mainly as follows:First,by analyzing the structure and characteristics of high-medium distribution system,the three level structure suitable for cooperative reliability assessment of high-medium distribution system was divided;and in accordance with the relationship between levels of coordination,the high-medium distribution system reliability assessment synergies model was established.Then,for the typical connection modes of high voltage distribution system as well as multi-contact structure in medium voltage distribution system,the high-medium distribution system failure affects collaborative analysis methods was porposed,the high-voltage power distribution system progressive failure impact analysis model and medium voltage multi-contact system failure recovery model were established.Finally,combing the analytical method of reliability evaluation,the high-medium distribution system reliability assessment method based on multi-level collaborative analysis was built.The effectiveness of the method was verified by numerical example.