The transient oil pressure measurement as a diagnostic tool of the short circuitwithstand capability of power transformers

摘要

The diagnostic methods used today tornassess large power transformers can only give limitedrninformation about its short circuit strength. Therncontribution introduces a measuring system, based onrnthe recording of dynamic pressure oscillations of thernoil, initiated by the movements of the windings andrnclamping parts inside the transformer, e.g. in case ofrninrush currents. An evaluation of these signals inrnrelation to the causing currents can provide a criterionrnfor winding slackness due to ageing or a too strongrndrying procedure. Thus it can be an indicator for arnreduced short circuit withstand capability and therebyrnan useful complement and improvement of therntransformer diagnostic techniques known so far.