| With the continuous improvement of Mine modernization and the distance of underground power supply, the higher Reliability, security and continuity of the mine Underground Power Supply System are demanded. As the main protection of the mine Underground Power Supply System; the reliability and security of LV Feeder switch Comprehensive Protection is directly related to coal production and personal security. It is because of the terrible condition in underground faces that the electrical faults occur frequently in underground distribution networks, such as earth leakage, short circuit and so on. However, traditional feeder switchgear cannot satisfy the requirements of safety and reliability in power supply system due to complicated protective circuits and various pluggable units. Hence, it is important to develop a new measurement and control system with high properties and large capacity for LV feeder switch comprehensive protector.Based on analysis the Progress and Status of current domestic LV feeder switch protector, we design a kind of intelligent LV Feeder switch comprehensive motor protector, which use AT89C52 as Control Core and include many kinds of Protection functions, such as short-circuit, overload, Over voltage, under voltage, phase-failure, creepage, leakage protection and so on. Its central component is intelligent control unit. It can implement many kinds of protection, and own alarm, display, and control functions, and can realize "four distant"function by the net calorie or the interface converter such as telemetering, distant tune, remote control, distant message etc. In network system, we can monitor and control the protectors by superordination machine.The main work of this thesis is as follows: Fist of all, the present situation and the trend of development on the field of LV feeder switch protector at home and abroad are reviewed, and the problems existed in the present LV feeder switch protector are also introduced. At the same time, the necessity to develop the new measurement and control system is analyzed. Based on the rules of"Safety Regulation of Underground Coal Mines"and the demand for underground distribution networks, the function specifications and technical requirements are put forward in the thesis.According to the technical requirements of the protector, the fault characteristics and protective principle in underground LV distribution networks are analyzed in the second chapter, such as earth leakage, short circuit, over-load, over voltage, under voltage and so on.The hardware system of protector is analyzed in the third chapter, which include the System design of protection module and concrete circuit design of each part, finally the hardware antijamming has also been involved. According to the practical work environment of underground LV distribution networks, being aimed at different characteristic disturbance signal, various disturbance sources and the disturbance signal characteristic, Corresponding hardware prevention measures are applied. The Software of entire system adopts Structured Programming method, including the host monitor procedure and every function module functional element program; this makes the call of entire procedure nimble and the debug convenient. And the protector has the function of communicating with superordination machine, Superordination machine can read various parameter information which comes from protector, and it is easier to us to grasp various situations of underground LV distribution networks.It has been proved by the results of tests in the laboratory that the protector can detect all the faults exactly, reliably and quickly, and execute the corresponding protection; each index meets the design requirements. At the same time, the friendly human-computer can save the time to identify the types of fault and get rid of the fault, which may improve the production efficiency.
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