Transformer Oil Analysis
Transformers, Switch gear and Electrical apparatus contain insulating oil. The insulating oil must be able in suppressing electrical force generated in the internal mechanisms; transfer, and assist in dissipating heat; and be essentially free of potential reactivity and combustibility. The purpose of this page is to discuss testing and monitoring to improve reliability, safety and ultimately assuring the load is kept up in the way it was designed to do.
While it’s accepted that insulating oils can remain in service for lengthy times, as is true in any lubricant: contamination; changes in the properties of the fluid; and degradation in uncorrected systems; are very real consequences.
Testing insulating oil at intervals is a cost effective and reliable means of insuring long apparatus service life. Oil Science Laboratory has found that these minimum tests will provide the required acceptance levels:
- Dielectric strength, kV
- Moisture content
- Interfacial tension
- Neutralization number
- Color.
This group rapidly identifies problematic conditions as they are found. Dissolved gas analysis is additionally done using separate sampling device. To test these, sampling is done on de-energized apparatus as follows, having a pre-cleaned 1 pint sample container and a catch bucket purge one gallon from the port, the drain port or valve. With insulant flowing in the bucket take the one pint test sample. Close off, wipe clean and dry as usual and replenish fill oil. Attach label to test sample, provide support information which can be in a memo. Provide S/N or equip id; date and time of sample; temperature at sample if known; kV rating. Oil Science Lab will take it from there.
Dissolved gas analysis DGA
When properly done in the laboratory DGA is an effective, reliable method of determining abnormal operating parameters of transformers and apparatus. There are normally four types of fault conditions that occur: Low energy sparking partial discharge; Localized overheating; General systemic overheating; Arcing, high current breakdown. DGA seeks to identify the precise gas content; measured in parts-per-million- and these reflect exactly on the condition causing the measured result. Advice is provided to the the utility client of maintenance to be done – that it can be Scheduled.
DGA samples are taken in a special syringe, 50 ml sample volume. Oil science provides these syringes at no up-front costs for your sampling project. After determining the number necessary Contact us for the syringes you need for your sampling project.
Question:
What can I and my company expect to achieve through periodic testing? .
- Saving serious money by avoiding failure.
- Maximum extension of transformer service lives.
- More efficient use of manpower, facilities, costs, materials.
- Scheduled maintenance, not emergency maintenance.
- Avoiding unfavorable press, local news media releases.
