HVSM strive to keep up with the latest technologies that benefit our clients. Our recent investment in a ‘TDS NT 60’, and extensive training enables us to offer PD testing in conjunction with VLF testing using the new 50Hz technology.
Our services include on site commissioning and maintenance testing of land and subsea HV cables, using 60KV VLF offline MV test units with PD diagnostic test technologies.
VLF is used for any application requiring AC testing of high capacitance loads. The major application is for testing solid dielectric cables (per IEEE400.2)
Unlike a standard VLF test, a combined VLF / PD test provides a full condition assessment. Impurities/damaged insulation, poor splices or terminations can be identified at installation stage. Many failures are due to damage during installation and or defective workmanship. Best practice recommends VLF/PD Testing of every newly installed or repaired cable before energising.
VLF/PD testing will identify & locate potential faults on Medium and High voltage cables where traditional methods could not.
Benefits of using VLF / PD testing:
- Our VLF test with its 0.1 Hz cosine rectangular wave technology is currently the only technology with
- Operational Frequency
- Integrated leakage current measurement
- Cable preserving
- Low energy consumption
- Integrated discharge and earthing facilities
- Full safety standards
- PD testing with mapping which shows location of any defects
- PD testing can pick up failures that VLF testing cannot detect
- Maintenance on cables can be scheduled and unplanned outages dramatically reduced, saving (down) time and money.
- Deterioration of cable and/or accessories caused by aging/oxidisation, construction work or seismic events can be detected and located.
‘Hi-Pot DC testing’, has now been superseded by this VLF/PD method, as it is a more effective way of testing and does not expose the cable insulation to the harmful effects of DC testing.
This method is now recognised by the Power industry (and is recommended by the IEEE) for testing of XLPE and FPR cables
HVSM offer VLF cable testing for voltages in the voltage range up to and including 60kV with a maximum length of 12Km.
Time to Change
It is now generally recognised within the industry, that ‘DC Hi-Pot’ testing of PE/XLPE insulated cables is not only ineffective but is also damaging to solid dielectric cable insulation.