Dornenburg's Method

The Dornenburg ratio method makes use of the ratios of the concentration of the key gases hydrogen, methane, ethane, ethylene and acetylene. The following ratios are used CH4/H2, C2H2/CH4, C2H4/C2H6 and C2H2/C2H4. For this method to be a viable diagnostic tool a few criteria have to be met. This in itself is the negative aspect of this diagnosis method as there are more...

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Dissolved Gas Analysis Methods

Power transformers play a key role in any power network and must be maintained and effectively monitored with continuous condition assessment to ensure reliability of the network. Numerous techniques have been developed over the years for the detection of transformer faults.  Some of the conventional parameters used are dissolved gases, furfuraldehyde, degree of polymerisation of...

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Solubility of Dissolved Gases

Different gases/parameters have different solubility levels in mineral oil [DiGiorgio1]. It is important to correctly identify the levels of gases produced in the associated defective conditions before any dissolved gas analysis is attempted. The following table provides solubility levels of the gases in transformer mineral oil with a static equilibrium at 760mm Hg...

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Dissolved Gases

Dielectric oil and solid cellulose dielectric materials when degrading under thermal and electrical stresses produce gases of varying compositions and in concentrations relative to the severity of the stresses applied to these materials [Griffin1]. These gases dissolve in the oil where the nature and concentrations of the dissolved gases sampled provides a good representation...

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Ageing Components and By-products: Organic

The power transformer basic components, which are organic in nature, are the insulating oil and cellulose based insulation (paper, insulation boards and blocks) [Heathcote1]. These components form the basis for the transformer health or life, as these are usually the fastest degrading materials making up the transformer [Emsley2]. Solid Insulation The solid insulation...

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Ageing Components and By-products: Main Structures

A power transformer is composed of a core, set of windings, oil, tank, bushings, tap changer and other auxiliary equipment. Each of these components is manufactured from either metals or compounds that are organic in nature. The different types of material react differently to the different fault conditions and the rate of energy release in the vicinity. This study examines...

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Transformer Life

Power transformers are generally designed for an operating life of 30 to 35 years. However, depending on how the transformer is operated, maintained and exposed to external risk these values may be less. Over the last 20 years trends have indicated that the transformer life has been much lower than expected. Even within Eskom, from statistics since the early 1990’s it was...

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