Analysing Dielectric Oils

Transformers can be affected by a broad range of internal and external conditions which, as time goes by, may lead to a reduction in the reliability of the equipment and the rapid ageing of it, as a result of which the insulation, in particular, may be affected.

The transformer is the piece of equipment that accounts for the biggest investment in an electrical installation, and the huge indirect costs that an unscheduled shutdown in the service may entail make it necessary to ensure that the transformer functions within an acceptable reliability regime through the introducing of predictive maintenance. Experience indicates that about 20% of transformers have latent defects that could result in an unscheduled shutdown.

Predictive maintenance applied more widely is the analysis of dielectric oils. The diagnosis of the state of the transformer and the insulation system, in particular, is carried out by means of a series of analyses of the dielectric oil, which we have grouped as follows into:

• Programme P1: Set of analyses that are performed on the dielectric oil to identify its physico-chemical state.
• Programme P1 Plus: The same as Programme P1 plus Particle Counting. Recommended when Dielectric Rigidity is low.
• Programme P2: Analysis of gases dissolved in the oils and geared towards identifying the possible presence of some latent defect in the transformer.
• Programme P2 Plus: An analysis that complements that of Programme P2 by adding furan derivative analysis in order to identify possible deterioration or ageing of the solid insulation.

Once the corresponding analyses have been carried out, a report on the results plus the analysis of the corresponding diagnosis is submitted.

Benefits

Having available a performance-based maintenance report provided by the analysis of the dielectric oils plus an assessment, diagnosis and recommendations provides our clients with the following benefits:

• Reduced operating and maintenance costs
• Fault prevention and increase in reliability
• Extending of the transformer’s useful lifetime

Advantages

• Sample-taking kit: Syringe and hermetic aluminium container to ensure conservation and the validity of the results, thus complying with the terms of the current regulations on sample taking.
• Client access over the Internet: The client may access his/her personal account to monitor the results and historical data, and even take advantage of the possibility of having the indicators plotted on graphs.
• Technical consulting.
• Cutting-edge equipment: Bureau Veritas Oil Condition Monitoring has equipment that improves the accuracy, capacity of the analyses and response times.
• Expanded diagnosis: The performance-based diagnosis provides information about which part of the transformer could be displaying a potential defect or fault.

The report on a real case can be downloaded here:

Report for dielectric

Choose the analyses that best suit your needs from among the whole range we carry out:

Draw up your own testing programme

Or else you can select one of the testing programmes we recommend at this other link:

Programme of recommended tests

If you would like to improve your knowledge about oils of this type, please do not hesitate to enrol for the course on “Transformer Chemistry”, which we run every year.

Jornada “Explotación óptima y fiable de transformadores”