Research On Urban Distribution Network Closed-loop Operation Analysis System

Urban distribution network closed-loop operation as an effective means, which can enhance the reliability and quality of the power supply, has important significance to the intelligent distribution network development. But closed-loop operation will alter the structure of power grid, produce the problem such as closed-loop current, and affect the safe of power grid. So we need to study closed-loop operation process, and develop a set of closed-loop operation analysis system to help the operation personnel. The system will provide a fast and accurate analysis to ensure that the closed-loop operation safe and reliable, it also can avoid to experience, improve the intelligent level of distribution network closed-loop operation.First of all, in this paper, considering the actual situation of the urban distribution network that is closely connected with the transmission grid, so the calculation method of system is used by BX type solution fast decomposition. Consider some kinds of feeder load under different conditions, and establish four load equivalent models. Based on those, distribution network closed-loop model is set up, and the closed-loop current are analyzed in detail.Secondly, the paper also analyses the influence of relay protection and equipment lines, include the analysis of zero sequence over current protection, current protection and the line, and sums up the security check.Finally, the paper uses Microsoft Visual Studio 2010 to develop an analysis system which based on Windows operating system. In accordance with requirements of the system design thought and the overall design, the system architecture, interface, and the safe protection and so on has carried on the design. And also introduce the details of the system's main function module. Lastly, building Lanzhou power grid by system, and selecting one of the closed-loop to carry on the calculation and analysis. In addition, the flow control measures are given, which has certain guiding significance to the distribution network closed-loop operation.