Based Microcontroller Mine Explosion-proof Switch Protection Device Design

The flameproof high-voltage switches used in coalmines in China have experienced stages of pitch insulation, oil insulation, sulphur hexafiuoride insulation and vacuum insulation respectively, in the course of which, accordingly, their ways of protection have developed from those of short-circuit and short-voltage to an integrated one with short-circuit, overload, insulated cable monitoring, electric leakage, short-voltage and over-voltage protection. Traditional integrated protection apparatuses, which employed simulated electronic ones composed of separate components, have shortcomings of large volume, inconvenient parameter adjusting, inaccurate parameter value setting, poor interchangeability and unreliability of operation. With the mechanization and electrization of China's coalmines developing rapidly, computer technology has been widely used in various aspects of coalmining, which poses higher requirements for the integrated protection apparatus of high voltage switches. In addition to protection, new functions such as remote monitoring of switch apparatus utilization, remote controlling of switch operation and parameter adjusting are needed.On the basis of the simulated electronic integrated apparatus composed of separate components previously manufactured in our factory, through practically investigating and extensively consulting related references, this project carries out the research and development of coalmine high voltage switch integrated protection apparatus controlled by single-chip microcomputers. Closely combined the requirements of China's coalmines for the operation of high voltage flameproof switches, this project develops the protection system with single-chip microcomputers of P89C51RD2 type, enabling the integrated protection apparatus to have six protection functions including short-circuit, overload, electric leakage, cable insulation monitoring, short-voltage and over-voltage. Armed with 128×64 dots monochrome graphic lattice VFD, this new developed apparatus has four display functions, normal state, error state, parameter adjusting state and error inquiry state. With communication technology applied and the help of 485 bus and MODEM, the data such as the apparatus' working states, present current, voltage and so on, are sent to the computers on the surface of ground. Based on the statistic data analysis made by software, these computers can be used to carry out the real-time monitoring of the coalmine high voltage switches, and the remote controlling of the high voltage switch operation and their parameter adjustment. Compared with traditional ones, this apparatus has such advantages as wide range of application, convenience and accuracy of parameter adjustment, reliability of operation, strong anti-interference, remembering memory, low manufacturing cost, strong interchangability, high economic profitability and etc..