PA63-RL regional interlock intelligent optical protection device (refer to the device below) is developed and produced by Nanjing Intelligent Apparatus Co., Ltd. (INT) . By absorbing advanced technology and according to China's demand for mine power systems, the product is specifically suitable for coal mine monitoring and high security switch protection system covering underground 10kV, 6kV and 3.3kV power neutral point unearthed or arc suppression coil grounding system.