Online dissolved gas analysis used for transformers – possibilities, experiences, and limitations

Christof Riedmann*, Uwe Schichler, Wolfgang Häusler, Wolfgang Neuhold

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review


At a time when the optimal utilization of resources is becoming ever more important, the condition monitoring of electrical equipment is also becoming increasingly essential. The dissolved gas analysis (DGA), an internationally accepted method for the condition assessment of transformers, plays a key role in this respect. By continuously monitoring the key gases in a transformer, incipient faults can be detected at an early stage and suitable maintenance measures can be initiated. This ability to plan maintenance measures may provide the key to cutting costs and increasing the overall system reliability. In free-breathing transformers, degassing or gas dissolving can occur over time, which may influence the interpretation basis of the DGA. The reason for this is that molecules always strive for equal distribution in a chemical-physical system. Various theories, which are based on the determination of physical and chemical material properties, can be used to describe these processes. Here, the Henry constants describe the concentration equilibrium at the phase interfaces and the diffusion coefficients describe the movement of the gas molecules dissolved in mineral oil. This paper presents mathematically or experimentally determined values and compares them with the literature. Furthermore, it describes the influence of the key gases investigated and the temperature dependence.

Translated title of the contributionKontinuierliche Gas-in-Öl-Analyse bei Transformatoren – Möglichkeiten, Erfahrungen und Grenzen
Original languageEnglish
Pages (from-to)88-97
Number of pages10
JournalElektrotechnik und Informationstechnik
Issue number1
Publication statusPublished - 16 Feb 2022

ASJC Scopus subject areas

  • Electrical and Electronic Engineering

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