Transec Online Transformer Drying

Online moisture monitoring and drying for oil-insulated transformers.

Overview

Transec online transformer drying continuously removes water from the insulating oil of in-service power transformers using an online molecular sieve, dehumidifying the paper insulation without an outage. Raptronics supplies Transec to utilities and industrial transformer owners who want to extend the life of their fleet.

Moisture is one of the main drivers of transformer ageing. Most of the water in a transformer sits in the paper insulation rather than the oil. Wet paper ages faster, loses dielectric strength and raises the risk of gas bubbles forming when the transformer is heavily loaded. Once paper has aged, it cannot be restored.

By drying the oil continuously, Transec draws moisture out of the paper over time. Combined with online moisture monitoring, it keeps the insulation permanently dry, arrests ageing and significantly extends transformer life expectancy.

Raptronics supports the project from the first suitability check, using your oil test results and nameplate data, through to installation planning and interpretation of the moisture data once the system is running.

Specifications

Drying method
Online molecular sieve
Outage required
No, operates on in-service transformers
Monitoring
Online moisture monitoring

Types

  • Online drying

    The drying unit is connected to the transformer and circulates oil through a molecular sieve that traps water. Because it runs continuously, drying happens gradually at a pace the paper insulation can follow.

  • Online moisture monitoring

    Moisture monitoring tracks the water content of the transformer over time, showing how the insulation is responding and when the sieve needs attention.

Applications

  • Transformer life extension

    Older transformers where replacement is years away and slowing the ageing of the paper insulation is the most cost effective option.

  • Online moisture removal

    Transformers with high moisture readings where an outage for offline drying is difficult to schedule or too costly.

  • Condition monitoring

    Fleet programmes that want continuous moisture data to support maintenance and replacement planning.

Applicable standards

We carry the applicable standards for your voltage class. Please reach out with your inquiries for more details.

Lead time

We offer very competitive lead times. Reach out and share your forecast with us in advance, and we can guarantee your requested lead time is met.

Frequently asked questions

Does Transec require a transformer outage?

No. It works on in-service transformers, removing water from the oil while the transformer stays energized.

How does drying the oil dry the paper insulation?

Water moves between the paper and the oil until they reach balance. When the oil is kept dry, moisture gradually migrates out of the paper into the oil, where it is removed by the molecular sieve.

Why does moisture matter in a transformer?

Moisture speeds up ageing of the paper insulation, lowers its dielectric strength and raises the risk of bubble formation during heavy loading. Paper ageing is irreversible, so keeping it dry protects the life of the transformer.

Who supplies Transec?

Raptronics supplies Transec as the manufacturers' representative, supporting suitability checks, quotation and installation planning.

How is online drying different from offline drying?

Offline drying takes the transformer out of service and dries the insulation in a concentrated process, often with heat and vacuum. Online drying works continuously while the transformer stays energized, removing water slowly as it migrates out of the paper. It avoids the outage, and the moisture monitoring shows the progress over time.

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