Abstract: Short circuit protection of high-voltage power lines in coal mine cannot realize selectivity with existing protection systems. To solve this problem, a scheme of protection and monitor underground based on PROFINET was proposed. The system is mainly composed of PROFINET network, monitor, controller, and integrated protector with PROFINET IO interface circuit. The system achieves protection and power monitoring network integration, completes the selectivity of short circuit protection, and can determine fault position quickly. Thus the troubleshooting time is cut and reliability of power supply network is improved. The simulation results show that the POROFINET real-time meets the requirement of protection and the system can realize short-circuit protection and power monitor function.

Key words: coal mines, Ethernet, relay protection, monitoring, real time control