Very Low Frequency High Voltage Cable Testing Equipment ,
Acceptance Test Eqipment , VLF Cable Tester
I. Application :
Model VLF-80KV/0.1Hz is designed to perform on-site withstand
voltage test with very-low frequency technology for power generators or 35KV and below XLPE power cable.Compared with Hipot test set at
main power frequency, VLF HV Test Set just needs much small test
power capacity(About 1/500 in theory). Its size and weight also is
decreased greatly. Specially the appearance of surveillance can
discover the generator insulation abnormal phenomena such as
surface corona, discharge and so on.
The test set consists of a control box, two HV boosters, a
compensation capacitor and a discharge rod.Based on electronic
frequency conversion and microprocessor controlled technology, it
has excellent performance.
It is prohibited to boost voltage without load, or to connect with
resistive load. If the specimen capacitance is less than 0.05uF,
the test set output waveform will be bad. For better performance,
optional capacitor is necessary to connect.
Until now , the designed test set also forms many different serialized model according to different withstand test applications through HV
booster number of configurations in each set, The alike model can
see other typical model at following clause.
II. Supply list of this Model:
| Sn | Description | Quantity |
| 1 | VLF Measurement and Control unit | 1 | unit |
2 | 50KV HV Booster | 1 | unit |
| 30KV HV Booster | 1 | unit |
| 3 | Discharging rod | 1 | unit |
| 4 | Load Capacitor, 0.04µF | 1 | unit |
| 5 | HV Test/Connection Cables | 1 | set |
| 6 | Earth cable | 1 | unit |
| 7 | 20A Fuse | 5 | unit |
| 8 | Print paper | 2 | unit |
| 9 | Manual | 1 | unit |
| 10 | Factory test report | 1 | unit |
III. Product Feature :
- Electronic frequency conversion
- Microprocessor Controlled
- Two HV boosters, 90KV output in series; or 40KV/50KV for single one
- Large LCD display
- Sine Wave Output
- Overvoltage protection, action time is less than 20ms
- Over current protection for both input and output side, action time
is less than 20ms
- Output current/Voltagewave form is sampled at high voltage side
directly
- HV Current Limiting Resistor inside
- Micro-printer inside
- Output voltage will not be affected by capacitive current during
test since closed-loop negative feedback design
VI. Optioonal Model and Test Range:
| Model | Peak voltage | Measuring range | Weight | Test object range |
| VLF-30 | 30KV | 0.1Hz,≤1.1µF | Controller: 4 kg Booster: 25 kg Size: L*W*H 323*174*323 | 10KV and below voltage cable,generator |
| 0.05Hz,≤2.2µF |
| 0.02Hz,≤5.5µF |
| VLF-50 | 50KV | 0.1Hz,≤1.1µF | Controller: 6 kg Booster: 45 kg Size: L*W*H 357*210*365 | 15.75KV and below voltage cable, generator |
| 0.05Hz,≤2.2µF |
| 0.02Hz,≤5.5µF |
| VLF-60 | 60KV | 0.1Hz,≤1.1µF | Controller: 6 kg Booster: 50 kg Size: L*W*H 357*220*370 | 18KVand below voltage cable, generator |
| 0.05Hz,≤2.2µF |
| 0.02Hz,≤5.5µF |
| VLF- 80 | 80KV | 0.1Hz,≤1.1µF | Controller: 8 kg Booster: 90 kg Size: L*W*H 357*240*390 | 35KV and below voltage cable, generator |
V.Test Connection Figure
1. For XLPE cable under 80KV test voltage
2. For Generator stator under 50KV test voltage
VI.Test Model Selection
1.For cable test
Test peak voltage formula: Ｕmax＝3Ｕ0,
Ｕ0＝Single-phase rated voltage of cable
Test time :60mints
2. For generator stator
Ｕtest＝1.414*βKＵ0,
Utest---- 0.1Hz peak test voltage (kV);
β-------0.1Hz and 50Hz voltage equivalent factor, usually taking
1.2;
K------ Usually take 1.3 to 1.5, generally take 1.5;
Uo----- Generator stator windings rated voltage (kV);:
