Appointed by client to perform Partial Discharge (PD) Assessments on HV assets within several Wind Turbines Generators.
The Issue – Appointed by the client to perform Partial Discharge (PD) Assessments on HV assets within several Wind Turbines Generators (WTG)
At times this may be due to the slow and progressive degradation of the insulation over many years of energized service, however another possibility may be degeneration, this can destroy a perfectly good Bushing in a matter of hours.
We performed non-intrusive PD testing across the fleet of WTGs and identified potential PD activity at one WTG.
There was significant dB uplift at the HV Switchgear and at the HV/LV transformer installed within, as seen below on dB reading:
Note: Red trace is ‘base’ dB reading & Purple trace is ‘asset’ dB reading.
An oil sample was taken from the transformer and assessed at site with DGA results showing no abnormal activity within, therefore, suggesting that the potential PD issue as most likely to be on the HV cable terminations of the transformer.
Implementation of an Operational Restriction (OR) to enforce further precautions on Persons for entry into the WTG.
Replacement of HV Cables and Terminations.
Defective assets were replaced before the defect had an opportunity to materialise into a disruptive failure.