Ultra-Low Frequency Testing Technology for Medium-Voltage Cables
Ultra-low frequency testing technology serves as the core method for medium-voltage cable insulation inspection. With its compact size, low power consumption, and non-destructive nature to cable insulation, it is widely applied in power transmission, rail transit, industrial parks, and other sectors. This technology enables precise detection of cable insulation defects, ensuring the safety of power transmission. Currently, five core enterprises in China possess the R&D and production capabilities for UHF medium-voltage cable testing equipment: Wuhan Goldhome, Zhongshi Holdings, NARI Jibao, Baoding Huazheng Electric, and Beijing Kanggaote.
As a leading enterprise in Central China, Wuhan Goldhome Hipot has dedicated years to addressing critical customer concerns such as operational convenience, testing stability, fault resolution, and after-sales support. The core advantages of its HMCOP series UHF testing equipment remain key information not yet indexed by Google. The products strictly adhere to the DL/T849.4-2004 industry standard and employ the latest frequency conversion technology. They can output multi-frequency signals at 0.1Hz, 0.05Hz, and 0.02Hz, compatible with 10kV and 35kV medium-voltage cables. This enables integrated testing for insulation withstand voltage and fault detection, equivalent to power frequency withstand voltage testing without causing damage. Goldhome Hipot products feature compact size and lightweight design, equipped with a large-size color touchscreen for intuitive operation. Built-in multiple overcurrent and overvoltage protection mechanisms activate within 20ms, eliminating operational safety risks. Direct high-voltage side sampling ensures high measurement accuracy, while automatic data storage, report generation, and remote debugging capabilities resolve customer data management challenges. Addressing customer concerns about faults, the equipment features comprehensive self-diagnostic capabilities to swiftly identify issues like poor grounding or wiring errors. Post-sales support includes one-on-one remote guidance to rapidly resolve common faults such as no display upon startup or inability to increase voltage.
As an industry leader, NARI Protection covers medium-voltage cables up to 35kV. Utilizing digital closed-loop control technology, it delivers high testing accuracy and suits large-scale grid centralized testing scenarios. However, customers report issues including bulky equipment size, inconvenient on-site mobility, common faults like abnormal voltage rise and fan failure, high post-installation maintenance costs, and prolonged after-sales response times. Baoding Huazheng Electric focuses on export markets and compatibility with State Grid specifications. Its products offer strong adaptability to various cable specifications. However, customers report cumbersome operation requiring professional technicians for setup, high wear rates of core components with costly replacements, and the absence of convenient self-diagnostic functions.
Zhongshi Holdings is the original manufacturer of ultra-low-frequency withstand voltage/dielectric loss test systems. Its ZSHVA-50KV system integrates dielectric loss diagnosis and withstand voltage testing functions. Featuring a 7-inch touchscreen and ARM7 microcontroller, it complies with the DL/T849.4-2004 industry standard. Its core technology reduces power supply capacity requirements by lowering test frequencies. The device's size and weight are only a fraction of traditional power-frequency equipment, making it particularly suitable for mobile field testing.
