By hvhipot 
The VLF Hipot Tester is a high-voltage power supply equipment designed specifically for insulation and voltage withstand testing of power equipment. By outputting ultra-low frequency (0.01Hz-0.1Hz) high-voltage signals, it achieves non-destructive testing of capacitive equipment such as large generators and cables. Its core advantage lies in replacing the large test transformers required for traditional power frequency (50Hz) withstand voltage tests with smaller equipment volume and weight. In theory, the capacity is only 1/500 of that of power frequency equipment, while maintaining equivalent testing results.
The VLF Hipot Tester, with its characteristic of outputting ultra-low frequency (0.02Hz, 0.05Hz, 0.1Hz) high-voltage signals, is particularly suitable for insulation withstand voltage testing of large capacity capacitive equipment and is widely used in fields such as power, industry, and rail transit. The specific application scope is as follows:
1、 Testing of High Voltage Equipment in Power Systems
Insulation testing of power cables
Conduct factory tests, handover tests, and preventive tests on cross-linked polyethylene (XLPE) cables, oil paper insulated cables, rubber insulated cables, etc. For example, power cables with voltage levels of 10kV, 35kV, 110kV and above are evaluated for their insulation strength through ultra-low frequency and high voltage testing to detect defects such as local damage, aging or moisture.
Meets the requirements of international standards (such as IEC 60840) and domestic standards (such as GB/T 12706) for cable withstand voltage testing, replacing traditional power frequency testing to avoid equipment capacity pressure caused by high currents.
Power capacitor testing
Test the stability of the insulation medium of capacitive devices such as parallel capacitors, coupling capacitors, and filtering capacitors under high voltage. Ultra low frequency signals can reduce the charging current of capacitors, making them suitable for voltage verification of single or group capacitors, especially for on-site testing of large capacity capacitor groups.
Generator and motor insulation test
Conduct insulation withstand voltage tests on the stator windings (high-capacity capacitive loads) of hydro generators and steam turbine generators, as well as the insulation system of high-voltage motors. By detecting the presence of inter turn short circuits and insulation aging in the winding insulation through ultra-low frequency and high voltage testing, potential damage to the equipment caused by power frequency testing can be avoided.
Transformer accessory testing
Test the insulation performance of components such as the bushing and tap changer of transformers, evaluate their stability in high voltage environments, and ensure the overall safety of transformer operation.
2、 Industrial and Special Equipment Testing
High voltage bushing and insulator testing
Used for insulation withstand voltage testing of high-voltage through wall bushings, pillar insulators, suspension insulators and other equipment, especially suitable for outdoor substations, converter stations and other on-site environments, to verify their insulation reliability after long-term operation.
High voltage capacitor type equipment testing
Equipment containing capacitive components such as high-voltage capacitor type voltage transformers (CVTs) and lightning arresters are evaluated for their insulation medium’s electrical strength through ultra-low frequency high-voltage testing, ensuring the safety of the equipment under overvoltage conditions.
Cable accessory testing
Conduct insulation and voltage withstand tests on accessories such as cable terminals and intermediate joints to check whether the installation process is qualified (such as whether there are insulation defects caused by bubbles, poor sealing, etc.), in order to avoid cable failures caused by accessory problems.
3、 Rail Transit and New Energy Sector
Testing of Rail Transit Power Supply System
Conduct insulation withstand voltage tests on traction power cables and DC cables (such as DC 1500V subway cables) for subways and high-speed trains to ensure the safe and stable operation of the rail transit power supply system.
New energy power station equipment testing
In wind and photovoltaic power plants, insulation testing is carried out on the combiner cables and high-voltage equipment (such as high-voltage cables and capacitor banks) of the booster station to ensure the reliability of the new energy generation system in high voltage environments.
4、 Research and Quality Inspection Fields
Research on the Performance of Insulation Materials
Used for testing the electrical strength and aging characteristics of new insulation materials (such as new polymers and composite insulation materials) in the laboratory, providing data support for material research and insulation design.
Product quality inspection
Manufacturers of power equipment such as cables, capacitors, and insulators use ultra-low frequency high voltage generators as factory quality inspection equipment to ensure that the insulation performance of the products meets standard requirements.