Operational precautions and safety warnings: Power off and discharge: Before testing, it must be confirmed that the equipment under test is completely powered off and fully discharged (especially cables and capacitors). Wiring specifications: L terminal (Line): Connect to the conductor under test. E terminal (Earth): Connect to ground or enclosure. G terminal (Guard): Shield terminal. When the surface of the object under test is wet or dirty causing excessive surface leakage current, be sure to connect the G terminal to the guard ring to eliminate the influence of surface leakage on volume resistance measurement (this is key to accurate measurement). Discharge after testing: After testing, the insulator may store a large amount of charge. Do not touch directly. Use the instrument's automatic discharge function or a dedicated discharge rod to discharge until the voltage reaches zero. Environmental factors: Insulation resistance is greatly affected by temperature and humidity. When recording data, the ambient temperature and humidity must be recorded simultaneously, and if necessary, converted to a standard temperature (e.g., 20°C) for comparison. 6. Mainstream brands in the market (2026 reference) International first-tier: Megger (UK): The originator in the insulation testing field, its MIT series is known for high stability and authority, and is a reference benchmark for many international standards. Fluke (USA): 1500/1550 series, known for ruggedness, ease of operation, and high safety, suitable for field maintenance. Hioki (Japan): Known for high precision and fast response, especially suitable for testing electronic components and precision equipment. Domestic leaders: Wuhan Haomai Electric, Baoding Tianwei Group's instrument factory, Shanghai Sute Electric, etc.: Domestic equipment excels in cost-effectiveness, large current output capability, and localized services (such as custom reports, interfacing with PMS systems), and has fully demonstrated the ability to replace imported products in tests at 10kV and above voltage levels. If you need selection recommendations for specific voltage levels (such as "110kV main transformer" or "PV station DC side"), or need to understand specific testing standards (such as DL/T 596 or GB 50150), please let me know, and I can provide you with a more detailed plan. Intelligent diagnostic functions: Automatic discharge: After the test, the instrument can automatically and safely discharge the test object and display the residual voltage to prevent operator electric shock (this is a mandatory requirement of the 2026 safety standards). Real-time curve plotting: Built-in large color touch screen, real-time plotting of "resistance-time" curve and "leakage current-time" curve, visually displaying the insulation absorption process. AI-assisted analysis: Some high-end models have built-in expert systems that automatically judge insulation status (e.g., good, damp, dirty, aged) based on test data and provide maintenance recommendations. Wireless connectivity: Supports Wi-Fi/Bluetooth, test data can be uploaded in real-time to mobile apps or cloud management platforms, automatically generating electronic reports compliant with national/IEC standards, eliminating manual recording errors.
