Research on Computer Real-Time on-Line Monitoring and Early Warning System for Insulation State of Key Electrical Equipment in Nuclear Power Plant

This paper presents the design of an enhanced multi-channel portable program-controlled insulation resistance tester system. The automatic switching control system for multi-point measurement of insulation resistance meter is composed of hardware and operating software of the control box, which is used in conjunction with the insulation resistance meter of the corresponding model. The hardware of the control box is composed of PLC control system, PC terminal system, relay group and supporting electrical equipment. The conversion of weak current to voltage is realized by using high value resistor as feedback element. By combining the proportional method with the integrated circuit method, a unique enhanced multi-channel portable insulation resistance tester system is formed to overcome the shortcomings of a single resistance measurement method. The human-computer interaction is composed of microprocessor STM32, LCD driver RA8875, LCD screen, buzzer and LED indicator. Data storage is composed of STM32, USB interface, micro-SD card and its related protection circuit, its role is to store measurement data and communication with the PC. Simulation results show that the instrument has wide application range and high precision.