Research On Protection System Of Mine Combined Switch

Most of the electric power supply equipment in coal mine adopts one to one control mode,which will increase the connection cable,waste the resources,and can not communicate with each other.The degree of automation is low and the combination switch is very good.Research more reliable,more intelligent and more performance combination switch control system can do better to coal mine power supply safety.It is both necessary and important to be of practical significance.Aiming at the shortcomings and insufficientness of coal mine electrical switch,the necessity of designing a new type of combinatorial switch is put forward,based on the analysis of the disadvantages of the traditional intrinsically safe pilot circuit,a novel essential power supply circuit with optocoupler isolation is designed.According to the principle of voltage protection,overload protection and short circuit protection,the method of additional DC power source is adopted to correctly judge the fault branch for selective leakage fault detection.The corresponding electrical schematic diagram is designed.On the basis of theoretical analysis and electrical principle,an experimental verification circuit based on the control chip dsPIC30F6010A is built.The circuits of voltage sampling,current sampling,power factor measurement A/D reference source,communication and man-machine interface are designed in detail.Four kinds of control modes,including sequential control,combined control,double speed control and double machine dual speed control are completed,and the man-machine interface of touch screen is designed and the corresponding software program is compiled.Finally,the combined switch designed in this paper is tested,and the protection functions such as leakage latch,leakage protection,overload short circuit,undervoltage and overvoltage are realized.The experimental results show that the system meets the design requirements and verifies the rationality and feasibility of the design.