Analysis of gas composition in oil-filled faulty equipment with acetylene as the key gas

Abstract

The article presents results of oil-dissolved gas analysis for 239 units of high-voltage equipment with faults under which acetylene is the key gas. The analysis revealed 13 types of fault with acetylene as the key gas that are differentiated by values of the dissolved gas ratios, their concentrations, and fault nomographs. For each type of fault, graphic domains are plotted that, unlike the nomographs, allow taking into account a possible coordinate drift. A graphic domain based fault identification technique is introduced. The types of fault are briefly described, examples of their identification by different investigators given. Duval Triangle based comparative analysis of the equipment diagnosis data is performed. It is revealed that diagnoses made by different methods may differ significantly both from each other and from actual diagnoses. The results presented allow increasing fault identification accuracy via dissolved gas analysis data.