AC hipot tester VLF

DChigh-voltageportable

Overview
The Huazheng VLF Multifunction Hipot Tester is an industrial high-voltage test instrument for VLF AC dielectric withstand testing, Tan Delta measurement and optional DC/partial-discharge diagnostics on cables and HV components. It uses digital frequency conversion with microcontroller control to automate voltage ramp, measurement and protection, and features direct HV-side sampling with closed-loop regulation.

Key features

• Automatic VLF frequency conversion (0.1 Hz – 0.01 Hz) with microcontroller-managed voltage boost/buck and protection.
• Compact, fully electronic design with large color touchscreen showing output waveform and test parameters.
• Direct sampling of high-voltage current and voltage; closed-loop negative feedback prevents capacitive rise effects.
• Intelligent protection: automatic calculation of overvoltage/overcurrent thresholds based on sample capacitance and test voltage; automatic shutdown on fault conditions (overvoltage, overcurrent, low sample resistance, flashover).
• HV lead output options up to 150 kV for specific configurations.

Applications

• Dielectric withstand testing of medium- and high-voltage cables (factory and on-site).
• Insulation diagnostics for cable accessories, terminations, joints and motors.
• Commissioning, routine maintenance and acceptance testing in power distribution and industrial installations.

Models / Typical ratings
30 kV (peak) — auto frequency 0.1 Hz–0.01 Hz; load ≤ 10 µF; all-in-one weight ≈ 30 kg — used for tests on systems up to ~10 kV
40 kV (peak) — auto frequency 0.1 Hz–0.01 Hz; load ≤ 10 µF; all-in-one weight ≈ 30 kg — used for tests on systems up to ~10 kV
50 kV (peak) — auto frequency 0.1 Hz–0.01 Hz; load ≤ 6 µF; all-in-one weight ≈ 35 kg — used for tests on systems up to ~20 kV
60 kV (peak) — auto frequency 0.1 Hz–0.01 Hz; load ≤ 5 µF; all-in-one weight ≈ 35 kg — used for tests on systems up to ~25 kV
80/90 kV (peak) — two-stage step-up transformer variants; load and weight depend on configuration — for higher-voltage cable and motor tests

Technical specifications

• Rated output voltage: 30–90 kV peak (model-dependent).
• Output frequency: automatic conversion 0.1 Hz – 0.01 Hz.
• Load capacity: model-dependent (examples above).
• AC voltage resolution: 0.1 kV; voltage accuracy: ±3%.
• AC current resolution: 0.1 mA; current accuracy: ±3%.
• Voltage peak error and waveform distortion: ≤ 3%.
• Operating conditions: indoor/outdoor use; ambient temperature −10 °C to +40 °C; humidity ≤ 85% RH.
• Input power: typically 230 V ±5% 50 Hz (or 120 V ±5% 60 Hz options).
• Ground detection: voltage boost disabled if proper grounding is not detected.

Options & notes

• Optional modules: DC testing, dielectric loss (Tan Delta), partial discharge (PD) measurement, capacitance and insulation resistance measurement during tests.
• For ratings >60 kV units may include an integrated series step-up transformer to increase load capacity while limiting overall weight.