Factory acceptance test (FAT) 22 kV subsea cable

As part of a FAT for a new 22 kV submarine cable, a Damped AC (DAC) high voltage withstandtest was performed. The high voltage test was combined with sensitive partial discharge diagnosis.

The partial discharge test were performed in accordance with IEC 60270 and is intended to reveal minor insulation weaknesses that otherwise may have passed a pure withstand test. Using TDR methodology, these weaknesses will be located along the cable with very high accuracy.

Before testing, the cable and test system must therefore be calibrated. This is done by submitting pulses of different sizes and calculating the time difference between injection pulse and reflection pulse. In this case, we could calibrate down to 100 pC.

During the withstand test, the test voltage was gradually increased from 0 kV and up to the maximum test voltage. At the same time sensitive PD monitoring was carried out. No PD activity was detected above the noise level in the site and cable could be approved.