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Condition assessment and commissoning of MV & HV cable systems

Testing provides knowledge about the state of cable insulation, joints and terminations. As a acceptance test new cable systems can be cleared. As a maintenance test this knowledge contributes to the right decisions regarding maintenance, replacement or residual assessment. 

Cable diagnosis with Damped AC (DAC)


Damped AC is a proven and recognized technology for high voltage diagnostic testing with application of IEEE, IEC, CENELEC and Cigrè.


With a test frequency between 20-500 Hz similar conditions as during normal operation (50Hz) are achieved. This helps to detect weaknesses that are active during normal operation. The diagnosis can be performed on all types of cables from 6.3 to 72,5 kV. With single-sided measurement, a minimum of 15 km of cable can be tested. For extra-long cables, two-sided measurement can be used.

DAC PD diagnosis:

PD testing is the best way to reveal and locate weaknesses in cable, joints and terminations. PD diagnosis with DAC reveals small weaknesses in cables, joints and terminations that otherwise whould pass an pressure test.

  • PD measurements according to;IEC 60270, IEC 60885-3, IEEE 400.3

  • PD mapping (Localization < 1 meter)

  • PDIV (inception voltage)

  • PDEV (extinction voltage)

  • PRPD 

  • PD level (Amplitude/Repetitionrate)

  • PD patterns and parameters similarity between the results of DAC tests and continuouspower frequency (50/60 Hz) factory tests

  • Reveals typically installation errors in joints and terminations such as;

    • Bad XLPE insulation preparation (cuts & dirt)

    • Poor removal of the semicon

    • Poor heat shrinking technique

    • Wrong stress control assembly


Damped AC methodology is in accordance with relevant international standards and recommendations: 

  • IEC 60060-3

  • IEC 60502

  • IEC 60270

  • IEC 60885-3

  • IEC 60141

  • IEEE 400

  • IEEE 400.4

  • IEEE 400.3

  • CIGRÈ Technical Brochure 502

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