Service
Power transformer maintenance
Preventive, corrective and major maintenance for distribution and power transformers from 75 kVA to 230 MVA, under IEEE C57 and IEC 60076.
A maintenance program that preserves the dielectric integrity of the insulation, the health of the core and windings, and the operation of the critical accessories of your transformer. Every intervention closes with a documented test protocol.
Maintaining a power transformer means preserving four systems that age at different rates: the dielectric integrity of the insulating oil, the condition of the solid insulation (paper and barriers), the mechanical health of windings and core, and the operation of accessories — bushings, radiators, tap changer, Buchholz relay and protective devices.
A correct program is not a generic checklist: it is designed from the equipment's rating, age, load regime and the results of previous tests. The difference between maintenance that extends service life and maintenance that just ticks a box is the diagnosis that precedes it.
At TEVKO we document every intervention with real electrical values — insulation power factor, insulation resistance, turns ratio, winding resistance — and oil parameters, so the client has traceability of the asset's condition between one service and the next.
Maintenance modes we perform
External preventive maintenance
Inspection and cleaning of bushings and connectors, radiators, fans and pumps, control cabinet, protective devices, level and temperature indicators, Buchholz relay and silica gel replacement.
When it applies: Asset in normal operation. Annual or per defined cycle.
Major maintenance
Internal intervention, winding clamping re-torque, tap-changer service and full oil processing.
When it applies: When diagnosis justifies it, typically every 8–12 years.
How we execute the service
Context
We understand the asset, its history and the real problem before proposing anything.
Diagnosis
We measure condition with Omicron and Megger instrumentation and compare against standards.
Intervention
We execute the solution the diagnosis justifies, with safe maneuvering and coordinated outage.
Result
We verify with tests and deliver a documented protocol with recommendations.
Frequently asked questions — power transformer maintenance
How often should a power transformer be maintained?
IEEE C57.106 and IEC 60076 point toward annual visual inspection and oil sampling, full electrical testing every 2 to 4 years by criticality, and major maintenance every 8 to 12 years. The exact program adjusts to the asset's rating, age and load regime.
What is the difference between preventive, corrective and major maintenance?
Preventive is done on a healthy unit to avoid failure; corrective addresses a detected anomaly; major involves deep internal intervention. Which one applies comes from the diagnosis, not age alone.
Does the transformer need to be taken out of service?
It depends on scope. Thermography and oil sampling are done energized. Full electrical tests require the transformer de-energized and a coordinated outage. We plan the outage to minimize downtime.
What instrumentation do you use?
High-precision Omicron and Megger instrumentation, plus a thermal camera. This lets us compare results against manufacturer reference values and the equipment's own history.
Power transformer maintenance in images
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Talk to a transformer specialist
Tell us about your asset and we'll respond with a diagnosis and a tailored quote — not generic pricing.