The system consists of monitoring terminal, cloud server and client terminal. Used for remote online monitoring of AC leakage and current, troubleshooting of circuit insulation failure, monitoring of intermittent leakage failure, checking the time of insulation failure, fault location, etc 1. On-line monitoring the AC leakage current and current. On-line monitoring the leakage current of low voltage transformer area. 2. Used to check the insulation fault of the circuit, monitoring the intermittent leakage fault, check the time of insulation fault, and locate the fault etc.