Optimization And Software Development Of Distribution Network Relay Protection System

Relay protection is the key part and plays an important role in the power system safety production. The four characteristics of relay protection: reliability, selectivity, speed and sensitivity, in a certain degree lie on the reliability of protection equipment itself and the rationality of protection setting. The distribution system, which locates in the end of power system, is the end of power energy transmission system, and supplies electric energy to users directly. The operation of distribution system has direct influence on the qualification of users' electric energy. It is the reliability of distribution network that influences users greatly. Above all, it will bring in important effect to optimize the distribution network relay protection setting scheme and configuration.Along with the incessant emergence of new technologies, the setting calculation of relay protection has become more and more difficult. The former hand-based with special count instrument setting calculation type has many limitations, such as the large quantity, time lasting, low precision of calculation, as a result, the efficiency is very low and can not meet the requirement of production. Along with the development of computer science and its generalization in the fields of research and manufacture, it has become a trend to finish the relay protection setting calculation with software. The research and exploitation of a practical power system distribution network setting software will be an effective way to boost the operation and management of distribution network relay protection, as well as to advance the productivity.In the first place, this paper briefly analyzes the importance of low voltage distribution network. Take the supply system of Yanzhou Xinglongzhuang for example, take into consideration of the short current data calculated by PSASP and the shortage of current protection principle, an optimized schemed is given. Take into consideration of the particularity of mine supply system, the optimization was made to every protection type. The optimized scheme can meet the requirements of power supply system, minimize the fault number. The analysis was made based on the four characteristics of the power system protection requirement.The distribution network protection setting software, based on the programming environment Visual C++, is based on the dialog frame. The software can carry out many functions, such as the system modeling on the graph editing environment, the short-current calculation, and the setting calculation of transformers as well as the lines in different types of setting schemes. The calculation results can be saved in the form of excel file, and it is easy to get the saved result during the running period of the software. The practical example analysis model, which is based on the system graph of Xinglongzhuang Mine, can show the different protection types of different lines in the graph. It is easy for the user to finish the setting calculation by click on the mouse in certain area of the graph.At last, this paper analyzes the possibility of introducing some other types of protection scheme to distribution systems. Such as: low-voltage protection scheme, quick-trip protection scheme.