Handover and preventive tests for cables using ultra-low frequency high voltage generator



The ultra-low frequency high voltage generator (VLF High Voltage Generator) is a precision instrument specifically used for insulation performance testing of power equipment. It outputs AC high voltage at 0.1Hz or lower frequencies to replace the traditional 50Hz power frequency withstand voltage test, especially suitable for on-site testing of large capacitive equipment such as cables and generators.

In simple terms, it is a device that "achieves great results with small means" — using a compact instrument to generate enormous testing energy, solving the problem of traditional equipment being bulky and inconvenient to carry.

⚙️ Working Principle: Why can it "achieve great results with small means"?

The core advantage of the ultra-low frequency high voltage generator stems from its working principle.

Replacing power frequency tests: When conducting power frequency (50Hz) withstand voltage tests on capacitive equipment such as large generators and long cables, a huge power supply capacity is required to provide capacitive charging current, resulting in bulky and heavy test transformers.

Reducing frequency to decrease capacity: According to theoretical calculations and practical proof, after reducing the test frequency to 0.1Hz, the required test power supply capacity is theoretically only 1/500 of that for power frequency tests. This allows the equipment to be made very lightweight while achieving equivalent insulation assessment effects.

Technical implementation: Modern equipment adopts digital frequency conversion technology and microcomputer control, converting input AC power (220V) into DC power, and then through inverter circuits and step-up transformers, ultimately generating precisely controllable 0.1Hz ultra-low frequency high voltage sine waves or cosine square waves.