Transformers are essential to most industries, providing power to site and sometimes specific pieces of equipment. A transformer failure can cause significant downtime, high repair costs and potential safety risks. Analysing your transformer oil can help to predict faults well in advance of any failure, maximising the life expectancy of this expensive equipment. Some issues such as the rate of breakdown of the thermal board insulating system, can only be detected through regular oil analysis.

Transformer oil analysis looks at both the physical and chemical properties of the oil, but also the concentrations of dissolved gases to allow a large number of issues to be detected and appropriate preventative actions to be taken.

Dissolved gas analysis looks at the concentrations and ratios of specific combustible gases, and uses this information to diagnose operational problems which may not be obvious through the physical and chemical analysis of the oil. For example, a high level of carbon monoxide could be indicative of the breakdown of the cellulose insulating board.

Contamination of a transformer oil by water or cellulose transformer board can reduce its dielectric strength. This is the maximum voltage that can be applied to the oil without electrical breakdown. A reduction in dielectric strength can mean that the oil is no longer able to provide the level of electrical insulation required.

An increase in moisture can not only potentially reduce the dielectric strength of the oil, it can also cause a breakdown of cellulose-based thermal insulation board. It is important to monitor the moisture content of the oil, particularly in environments where the temperature varies significantly and dissolved water is released during the transformer cooling process.

To determine the degree of aging of the cellulose thermal board, the Furan content is analysed. As the board ages, its degree of polymerisation reduces resulting in a decrease in mechanical strength. Furan derivatives form as a result of the breakdown of the polymeric structure of cellulose paper, and measuring their content in the oil allows us to measure the aging process of the thermal board.

We would recommend regular transformer oil analysis for all key transformers in your plant / on your site, to ensure that pro-active maintenance can be scheduled and implemented, maximising the life of your expensive equipment, and preventing costly downtime for your business. If you have any queries about transformer oil analysis, our team of experts are here to help.