Static Security Analysis Of The Distribution Network Based On The Busbar Automatic Transfer Switch

With the rapid development of social economy, all kinds of electricity load demand has increasing sharply, the impact caused by large-scale blackouts is becoming larger and larger, which puts forward higher requirements to power supply reliability and the ability. To ensure the network reliable power supply, we need to analyze the safety level of the grid operation mode, and the power system static security analysis. Through the simulating the accident which may occur in power grid operation, formulate the recovery scheme of contingencies, then provide help for the power restoration, which is an effective method to improve the power supply reliability.In the traditional power grid security analysis mainly centralized in the transmission network and build a relatively perfect transmission network security analysis system. Because of the difference existing in the distribution network and transmission network structure characteristic and a large number of Busbar Automatic Transfer Switch in the distribution network, transmission rule of N-land its safety analysis method are not applicable to the distribution network. Therefore, develop a static security analysis method in line with the distribution network structure and its practical operation conditions has important social and practical significance, which is good for optimizing network structure,improving the power supply reliability and promoting the development of the economy and social within the power supply area.In order to improve the precision of the distribution network static security analysis, the article based on N-1criterion of the transmission network come up with the distribution network security analysis method based on the busbar automatic transfer switch. On the distribution network security analysis process,there will be some difference in the distribution network closed loop design, open-loop operation structure characteristics and transmission network, so each branch breaking will influence on distribution system and it needs higher demand for the precision of the branch outage simulation. The paper first puts forward the accurate AC power flow breaking simulation directly on the branches,using more suitable distribution network behavior index to output the contingency table. Through the study of the distribution network of various connection analysis method, optimizating the traditional power system static security analysis method, improving branch breaking method and defining behavioral indicators to the biggest cause of accident, which has great impact on the distribution network, such as:power bus number, quantity, load bus voltage limit number, it output a more precise contingency table. Finally, according to the simulation contingency set recovery, it puts into the auto-switch-on device for the resumption of power supply after the accident. The paper uses the Visual Basic programming language to program the connectivity judgment procedure, Newton-Raphson power flow program, contingency ranking procedure; through the calculation example based on the distribution network in a certain area of Henan province, it proved that the research method is scientific reasonable and effective.