Air ingress in sealed power transformers has become a significant issue, as oxygen accelerates the aging of paper used in the insulation, it says.
Measuring total gas pressure (TGP) is a step forward from the traditional measurement methods that are currently available in the market to detect air leaks, says Vaisala. An oxygen sensor cannot detect an air leak if there is a reaction in a transformer that consumes oxygen. However, even if all oxygen has been consumed, the TGP value will still give a reliable indication of a leak because the nitrogen value will both dominate and increase over time, because it is neither formed nor consumed in the transformer. (The atmosphere is 78% nitrogen and 21% oxygen, by volume). Additionally, TGP measurement can indicate if the nitrogen cylinder of a nitrogen-blanketed transformer is empty – another task that oxygen measurement cannot detect.
The new measurement solution will be made available to the current customers via a software release for Vaisala’s Optimus DGA Monitor OPT100, said to be the world’s first maintenance-free dissolved gas analyzer for power transformers. For new OPT100s, the new software will be incorporated as a default factory setup.
