It is well known that DC testing of aged extruded cable such as XLPE and EPR is potentially damaging 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 even 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 utilising low frequency AC test systems.
VLF testing enables the cable test engineer to detect insulation defects before the cable fails in service.
The HVA60 High voltage universal test system from Macey’s Electrical provides the testing and commissioning engineer with a versatile high voltage power source suitable for testing electrical plant including cables: XLPE, PE, EPR, PILC etc, capacitors, switchgear, transformers, rotating machines, insulators and bushings.
The HVA60 High voltage universal test system has an advantageous power / weight ratio. At 59.8 kilograms, the HVA60 High voltage universal test system is one the light VLF test systems available today.
Apart from the VLF output, the HVA60 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.
In the VLF mode the HVA60 High voltage universal test system 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 HVA60 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.