Abstract: Taking a coastal new energy power plant in Guangdong Province as an example, this paper explores the issue of insulation performance degradation in the plant and the technical limitations of existing insulation monitoring devices. It then designs a novel type of insulation monitoring device. Through practical application, the new device has demonstrated a significant reduction in the frequency of insulation fault alarms, an enhancement in fault location efficiency, and an improvement in system reliability, fully meeting the operational requirements under complex environmental conditions.