Dry-type transformers
Cleaning dust and contamination from the windings and vents, torque checks, insulation resistance, winding resistance and turns ratio, plus a thermographic scan under load.
Transformer testing
Transformer testing and maintenance
We test and service dry-type and liquid-filled transformers: turns ratio, insulation and winding resistance, power factor and oil analysis, with cleaning and torque checks. Every unit is tested the same way, so the results become a baseline you can trend. Halifax and Calgary crews, serving sites across Canada.
What we test
Dry-Type and Liquid-Filled Transformers
One test program for the whole fleet, tailored to each transformer type.
Liquid-filled transformers
The same electrical tests, plus oil sampling for dissolved gas analysis (DGA) and oil quality: dielectric breakdown, moisture and acidity.
Fleet baselines
Every unit tested the same way, so healthy transformers can be told apart from those quietly degrading. See the pulp mill case study: 20 transformers, one baseline.
Part of the same shutdown
Transformer work is planned with switchgear and breaker testing, so one outage covers the whole electrical room.
Tests and service
What the test program includes
The exact list follows the equipment and its manufacturer's instructions. A typical program covers:
- Turns ratio (TTR) across all tap positions, to find shorted or open turns and tap-changer faults
- Insulation resistance with polarization index (PI), to reveal moisture or contamination in the windings
- Winding resistance, to find loose connections, poor contacts and winding damage
- Power factor (tan delta), one of the best early indicators of insulation aging
- Visual inspection, connection torque checks and a thermographic scan under load
- Liquid-filled units: dissolved gas analysis (DGA), to detect arcing, overheating or partial discharge early
- Liquid-filled units: oil quality (dielectric breakdown, moisture and acidity)
- Dry-type units: cleaning of windings, vents and enclosures
What you receive
A record you can file and act on
Every transformer gets a completed test record: nameplate, as-found condition and each result against the manufacturer's values, NETA limits and the unit's own previous results. Units worth watching are flagged with a recommended action.
Because the tests are repeated the same way, power factor and PI trends show insulation aging long before it becomes a failure, and DGA gives liquid-filled units an early warning no external inspection can.
On site
From a recent transformer test
How it works
Planned around your shutdown
- 01
Send the transformer list
Share the transformer list with nameplates, or photos of them, and any past test or oil results. We reply with a test program and quote within one business day.
- 02
Plan the outage
Electrical tests need each transformer de-energized and isolated, so outage windows are agreed in advance and combined with switchgear and breaker work where possible.
- 03
Test, service and report
Units are tested, cleaned and torqued, and oil samples go to the lab for analysis. Urgent findings are reported to your site contact before we leave, followed by the full report.
Where we work
Across Canada from Halifax and Calgary
Crews are based in Halifax and Calgary and travel to industrial, commercial, healthcare and institutional sites across the country, including remote and northern sites. Travel is set out in the quote.
All electrical testing services
Transformer testing questions
What's the difference between dry-type and liquid-filled transformer testing?
Both get turns ratio, insulation resistance, winding resistance and power factor tests. Liquid-filled units add oil diagnostics: dissolved gas analysis and oil quality tests. Dry-type units need their windings and vents cleaned, because dust and contamination are their main enemies.
Does transformer testing need an outage?
Yes, the electrical tests are done with the transformer de-energized and isolated. Infrared scans are done under normal load, so we can scan first and use the outage to test and fix.
What is dissolved gas analysis (DGA)?
Faults inside a liquid-filled transformer, such as arcing, overheating or partial discharge, release gases that dissolve in the oil. A lab analysis of an oil sample shows which gases are present, often long before the fault shows up any other way.
How often should transformers be tested?
It depends on the transformer's condition, how critical it is and its loading, as CSA Z463 describes. A first full test sets the baseline; after that, results that hold steady can be retested less often, and units that are trending get closer attention.
What does transformer testing cost?
It depends on the number and type of transformers, the outage windows, any oil analysis and travel. Send the transformer list and your preferred dates and we reply with a quote within one business day.
Building a transformer baseline?
Send us the transformer list; we quote the test program within one business day.