Study On Optimizing Over-current Protection Of Mine 35kV High-voltage Distribution Network

At present, our country's coal mining areas are universal existence for electrical network complex, movement way changeable, protective device in normal operation is effective and easy to trip by mistake when the electrical network breakdown and so on. The question has significant influence to the power of mining area security, reliability and economic benefit of mining area. Therefore, over-current protection of mine 35kV network optimization study has important significance.The paper analyses the power of mining area security and reliability, the tidal current distribution, electrical power loss and so on, can be determined optimization program of mine 35kV grid network; Through to analyze each kind of movement way of high voltage power system of mining area, determined apportion function is the best movement way finally; On the basis of the optimal movement way, considerate the requirements of mine power supply, proposed the optimization program of over-current protection of mine 35kV substation, it not only satisfy the requirements of over-current protection in normal conditions, but also considered the short-circuit protection in fault conditions; there are four protection programs of 35kV overhead line in this paper, and finally adopt the protection program of over-current fast breaks of based on the auto-adapted characteristic; because there are many cable segments in the underground high-voltage distribution network and the different short-circuit currents are very similar, so the paper proposed a new method, it is reverse computation.Through researching the demonstration and proved the validity of optimized over-current protection, using the software which this paper provided can get the optimal results and it is good to select the protection devices exactly. Through the studies of the optimal over-current protection can improve safety and reliability of the mine's power system.