DC testing of aged extruded cable such as XLPE and EPR is potentially damaging to the cable insulation causing premature failure of the cable under service conditions. Any form of DC testing has been found to be ineffective in detecting serious faults in such cables. It is because of these limitations that international and national bodies such as CENELEC, VDE, SABS and the IEEE now recommend testing by utilising low frequency AC test systems.
VLF testing enables the cable test engineer to detect insulation defects before the cable fails in service. In the VLF mode, the HVA 60 high voltage universal test system, available from Macey's Electrical , will output 60kV peak into a 1µF at 0.1Hz. However, as the VLF frequency can be adjusted, loads of up to 5µF can be tested with an output frequency of 0.02Hz. The output VLF waveform is load independent and symmetrical, thus avoiding destructive space charge effects caused by DC polarisation.
To further assist the operator, the HVA 60 high voltage universal test system will automatically calculate the optimum output frequency for larger loads. All test results are stored on a non-volatile memory for downloading to a PC for review and analysis.
The HVA 60 high voltage universal test system has an advantageous power/weight ratio. At 59.8kgs, the HVA 60 high voltage universal test system is one the lightest VLF test systems.
Apart from the VLF output, the HVA 60 high voltage universal test system can also produce either polarity DC together with a cable sheath/jacket testing modes. The output test sequences, which are easily set by the operator, can be either set manual or fully automatic operation.
Following are the features of HVA 60 high voltage universal test systems:
- Lightweight portable unit
- Solid state air insulated design
- True sine wave low frequency output
- Suitable for VLF, DC and Jacket/sheath testing
- Fault conditioning capability
- Test result storage capability
- Full short circuit protection with arc management regulation
- Provides compliance with CENELEC, IEEE 400.2 and VDE
- 0296 and other international standards
- Manual or fully automatic test sequence selection
- Real-time display of actual output waveform
The HVA 60 high voltage universal test system provides the testing and commissioning engineer with a versatile high voltage power source suitable for testing electrical plant including cables: XLPE, PE, EPR, PILC, capacitors, switchgear, transformers, rotating machines, insulators and bushings.