The Research On The Protection Of 10kV Dalian Distribution System And Its Reliability Analysis

As an important part of power system, distribution network plays an important role as the bridge connecting power grid and electric users. With the development of Smart Grid around the country, the intelligent distribution network construction should be without delay.At present, the development of distribution network in Dalian is relatively slow, the situation of distributed power supply network is still in the primary stage compared with the developed provinces and cities in the south. In the future, with the access of a large number of distributed power supplies, the operation mode and reliability of power distribution network will meet a great challenge.Based on Dalian power grid, this paper studies the protection and reliability of Dalian10 k V distribution network with distributed generations. Mainly to solve the distributed power access distribution network location and access capacity selection issues, protection program re-formulated and the distributed power distribution network reliability assessment.(1) This paper analyzes the characteristics of distributed power short-circuit current,analyzes the influence of distributed generations on fault current from two aspects of distributed power supply type and fault location, laying the foundation for the later protection scheme.(2) Based on the actual situation of Dalian power grid, the paper introduces and analyzes the status of Dalian distribution network system, the problems existing in system operation and protection, then introduces the standard and access mode of distributed power network in Dalian.(3) The ideals and setting principle of traditional three- stage current protection are analyzed. In order to solve the problem that the original protection of the distribution network is prone to be invalid, refusal and capacity limitation after the distributed generations are connected, an adaptive current quick-break protection method is proposed. According to the current system. The operating mode and the output power of adaptive adjustment of settings,greatly improving the distribution system protection performance. Finally, the proposed method will be supplied through simulation analysis.(4) Solving the problem of "where to access and how to select the distributed generations", in order to settle the foundation for the reliability analysis of the distributionnetwork with distributed generations. This paper presents an improved genetic algorithm Distributed power supply location constant volume method.(5) The objective of this method is to save the cost of power grid operation, which validated by simulation. Based on the distributed power supply location and capacity determination, the reliability of the distributed power distribution network is analyzed. Using the point estimation method, the reliability of distribution network with distributed power is evaluated. Finally, the proposed method will be supplied through simulation analysis.