Partial Discharge Case Study
From a High PD Reading to Avoiding Unnecessary Transformer Replacement
Helping a UK university use continuous partial discharge monitoring to avoid unnecessary transformer replacement and plan future investment with greater confidence
Project Snapshot
- Client - UK University
- Challenge - An elevated partial discharge reading had been detected on a transformer, but the facilities team could not tell whether it indicated imminent failure or manageable deterioration.
- ACTENIQ Support - Temporary nine-channel online PD monitoring across the transformer and associated switchgear.
- Outcome - The university continued operating the transformer through to its planned shutdown, deferred significant capital expenditure and moved to permanent monitoring.
One elevated reading. No clear indication of urgency.
The Challenge
A routine inspection identified a high partial discharge reading on a university transformer.
The reading showed that PD activity was present, but it could not reveal whether the condition was stable, worsening or likely to lead to failure.
The university had eight months until its planned summer shutdown. Replacing the transformer immediately would mean significant capital expenditure and disruption. Continuing to operate it without better evidence carried its own risk.
The team needed to understand how the asset was behaving over time before making the decision.
The ACTENIQ Approach
ACTENIQ installed a temporary nine-channel online PD monitoring system across the transformer and switchgear.
The system was deployed without a shutdown and continuously monitored the equipment over eight months.
This allowed ACTENIQ to assess how PD activity changed with load, humidity and other operating conditions, rather than relying on a single test result.
What The Data Revealed
The readings fluctuated, but remained within manageable tolerances.
There was no sustained escalation, severe spike or pattern suggesting imminent failure. The transformer was not deteriorating at the rate initially feared.
That evidence gave the university confidence to keep the asset in operation until the planned summer shutdown rather than replacing it prematurely.
The Outcome
The most important outcome was not simply that the transformer remained operational. It was that the university could make the decision based on eight months of evidence rather than a single moment in time.
The monitoring also gave the operational team clearer evidence when discussing future capital requirements, helping them demonstrate why investment may be needed and when it should be prioritised.
- Continue operating the transformer with greater confidence
- Retain its planned summer shutdown window
- Avoid an unnecessary emergency replacement
- Reduce operational disruption
- Build a stronger evidence base for future maintenance and investment
- Convert the temporary system into permanent monitoring
A high reading does not always mean immediate replacement
A one-off PD test can identify activity, but it cannot always show how quickly the condition is changing or how urgent the risk really is.
Continuous monitoring gives teams the evidence needed to distinguish between stable activity and genuine deterioration.
In this case, the university did not immediately need a new transformer. It needed clarity.
Unsure what an elevated PD reading means for your asset?
Speak to ACTENIQ about temporary or permanent online partial discharge monitoring for your electrical infrastructure.
