Détection des fuites dans les transformateurs industriels

Les transformateurs industriels sont très répandus et peuvent être extrêmement grands. Lors de la construction ou de la réparation d'un transformateur, il est essentiel de vérifier qu'il est parfaitement étanche. C'est d'une importance capitale, car les transformateurs sont remplis d'huile minérale qui sert à refroidir l'appareil, à l'isoler électriquement et à le protéger contre l'oxydation.

Si une fuite est détectée lors du remplissage, toute l'huile doit être vidangée avant que le problème puisse être résolu. Il en résulte une perte de temps et d'argent considérable.

Current method: air pressure test

At present, transformers are tested by filling them with dry air to an overpressure of 200–300 mbar. This pressure is maintained for several hours to check for any pressure drop, which indicates leaks. A higher test pressure is not possible due to the transformer’s construction. Components such as pressure relief valves, cooling fins and certain joints cannot withstand higher pressures. If a pressure drop is detected, a soapy water solution is used to locate leaks. All joints and connections are checked manually. The formation of air bubbles indicates a leak. 

This method is:

  • Very labour-intensive
  • Time-consuming
  • Prone to error, particularly with large transformers

It is therefore the case that leaks only become apparent once the transformer has been filled with oil and is operational.

Ultrasonic leak detection on depressurised systems with CS INSTRUMENTS

CS INSTRUMENTS has over 20 years’ experience in ultrasonic leak detection. This technology makes it possible to detect leaks without the system needing to be on overpressure. 

A compact ultrasonic tone generator is placed inside the transformer, requiring only an opening of 8 cm in diameter. Bespoke solutions are available for smaller openings. The sound source emits a powerful ultrasonic signal in multiple directions, which propagates throughout the entire transformer. An ultrasonic leak detector can then be used on the outside of the transformer to easily determine where leaks are located. Where a leak is present, the ultrasonic signal escapes and is detected by the leak detector responding to the ultrasonic tone.

Advantages of this method:

  • Leak detection from several metres away  
  • Fast and accurate localisation  
  • Option for visualisation and documentation (depending on the device)  
  • No pressure required → safe for all components  
  • Significant time savings: from days to minutes

Thanks to this approach, a complete transformer can be checked for leak-tightness quickly and reliably, with a significant reduction in working hours and the risk of missed leaks.