The Research On New Digital Protection System Of Underground Low-voltage Explosion-proof Switchgear

In coal mines, air is damp, the loads fluctuate frequently. In such harsh working environment, the insulation of power lines and electrical equipments easily aging or be damaged. The poor insulation usually causes leakage, short-circuit, over-voltage, under-voltage. If the fault line could not be disconnected immediately, the malfunction may have be worse and causes serious accident. So, the research and development of new digital protection system has very important practical significance and economic value.This paper analyzed the characteristics of low voltage power supply system in coal mines, according the peculiarity of every fault to distinct short-circuit or starting-up of large capacity motor, or distinguish which branch line has leakage fault. According to"the coal safety regulation", perfects the low-voltage explosion-proof switchgear digital protection system protection various function.The protection system based on a high-performance 16-bit microcontroller TMS320LF2407A. The application of large scale integrated circuit in hardware, makes sure a fast analsis of collected data, educes a correct judgement about the fault. The electromagnetic interference in the coal mine could not be ignored. According to different characteristics of the situation, we established corresponding prevention measures, in software and hardware, to ensure the protection system has a strong anti-electromagnetic-interference ability.The protection system has a good man-machine interface, the operation is simple. The experimental data of protection device shows that the protection system has a good performance which can satisfy the application in the mines.