Diagnosing axial displacement in an actual, single, isolated transformer winding: Experimental results

Localization and severity assessment of an axial displacement occurring in an actual transformer winding is reported. Axial displacements considered in this paper are still in their initial or incipient stages of development and so assumed to be physically confined between two consecutive double-disks. It is needless to emphasize that early detection of such a winding condition is crucial. In a recent paper, authors derived a generalized analytical formula that linked the harmonic sum of squares of short-circuit natural frequencies of the winding to the basic winding parameters, viz., capacitances and inductances (taken on a per double-disk basis). This formula was successfully used to localize a radial displacement. Proceeding further, it is now shown, how the same expression can be used to localize and assess severity of an actual axial displacement. A procedure is developed for this purpose. Its philosophy is explained, and thereafter, it is verified by experiments on a single, actual, isolated, continuous-disk transformer winding. The results seem to be promising.