Enhancing immunity of coalmining monitoring and communication system based on electromagnetic measurement

Stringing haulage motors were main underground conveyance equipments, but they were the strong electromagnetic interference sources. To resolve the problem of monitor system false alarm and mobile communication interruption, the interference generation mechanism and distribution characteristic were analyzed. The means of conducted interference circuit analysis and stray current quantitative analysis were adopted. A novel field way was put forward in which the radiated emission measurement in the coal mining roadway was accomplished. The data was acquired through the R&S spectrum analyzer FSP7. The conducted interference, stray current and radiated interference were the main factors of monitor and mobile communication malfunction. The anti-interference measures were taken, which included the power supply isolation, earth, the improved complex EMI filter and shield to radiated interference. Results indicate monitor system false alarm and mobile communication interruption have been eliminated completely. It is concluded that the electromagnetic compatibility of underground monitoring and mobile communication systems have been enhanced evidently with these anti-interference measures.