Development of protection device for anti-override trip based on optical fiber locking control

In order to solve the problem of override trip in high-voltage power supply system of coal mine, a new scheme for preventing override trip is proposed on basis of optical fiber locking control. Referring to a typical mine power supply system, the short circuit protection principle of high-voltage grid based on optical fiber locking is analyzed. The hardware circuit, as well as the control procedures of protection devices is developed, and the performance experiments are carried on. It is shown by experiments that the scheme can figure out the coordination between switchgears in high-voltage power grid of coal mine, and can solve the selective problem of over-current protection. In addition, the override trip fault can be prevented effectively. Therefore, through the scheme proposed in this paper, the reliability and safety of the mine power supply system can be improved.