PARTIAL DISCHARGE MAPPING (PDM)
PDM is a technique to measure partial discharge in medium & high voltage cable. It could quite accurately measure the magnitude and locations of partial discharge activities within the cables. It also helps to provide some information on the degree of deterioration of the insulating materials.
Partial Discharge:
- Electrical discharges occuring inside medium and high voltage insulation (flaws, cracks, voids, irregularities).
- These imperfections create voltage stresses and cause eventual failure of the insulation.
- Insulation failures begin with and are characterized by small but detectable releases of energy or Partial Discharge
Causes Of PD Occurrences :
- Cavities due to pour cable bending.
- Tracking between insulation paper layers.
- Joint insulation contamination.
- Pour epoxy resin hardening.
- Cavities in resin insulation.
- Cavities in the shrink type cable joints.
- Treeing on the conductor.
- Treeing over the surface of polymeric insulation.
Our PDM Technology & Equipment - Underground HV Cables
Onsite MV60 Damped AC
DAC voltage test and diagnostic measurements (PD and tan δ) provide for reliable detection of poor installation, failures due to inappropriate laying, failures in accessories or deterioration in cable insulation due to aging. DAC testing is an advanced maintenance tool which supports asset management and grid operation as well.
Megger MIT525
The MIT525 is compact, light 5 kV insulation resistance tester for the diagnostic testing and maintenance of high voltage electrical equipment. As well as measuring insulation resitance to 10 TΩ, the MIT525 also offers various diagnostic tests such as Polarisation index, Dielectric Absorption Ratio, Step Voltage, Dielectric discharge and ramp testing.
Megger TDR2010
Designed for the location of faults communication and pilot cables and some power supplies the TDR2000/3 and TDR2010 are tough. They are rated to CAT IV 150 V and are dust and weatherproof to IP54, so there are ready to work in the real world.
