Study On The Measurement And Control Protection System For Intelligent Combined Switchgear In Underground Mine

With the development of automatic technology in coal mining, more requirements are proposed to improve the continuity,reliability and security of coal mining power supply system. The work is proposed directing at the problems existed in the fully mechanized coal mining surface such as high voltage level, large power equipment, more kind of loads, complicated control modes, difficult trans-information and so on. However, because it is difficult to match the imported mining system with the electrical control equipments made in china,all 3.3KV electrical switchgears have to be imported from abroad in past years. Such a situation has resulted in many limits to develop domestic coal industry due to the high price, long supplying period and some technical index which can not meet the requirements formulated by national standard GB3836. It is of very important significance to develop the mining intelligent 3.3kV combined switchgear.On the basis of widely collection of material of the microprocesser-based power distribution system and the exprience of electrical power system relay protection, with the applying of micro-electronics and micro-computer technology, this article claims an proposal which integrates relay protection, control, display and arrangement to it and is more suit to the operation of electrical devices of coal mining.The development history and present situation of combined switchgear are reviewed, the significance and importance to develop the measurement and control system of combined switchgear are also introduced.In addition, according to the safety operating characteristics of underground 3.3KV electrical equipment, the fault characteristics and protection principle are simultaneously analyzed, the function parameters corresponding to the fault protection for high capacity motors are determined, the corresponding protection circuit are designed. The main protections of system have pilot control circuit, leakage lockout,leakage protection,short-circuit protection,overload protection, switched off protection and voltage protection. At the same time,module program design method and compiled main control program and function subprogram are emphatically described.The source interference is analyzed, and the corresponding hardware,software anti-jamming measures are formulated.especially, more attention is paid to the design philosophy, operation principle, hardware block diagram and software flow chart of this system.The system has been test in laboratory,the test results of combined switchgear proved that the system can detect all the faults exactly,reliably and quickly,and execute the corresponding protection.In addition,It has stable performance,reliable action and a high application value.