METHOD OF VIBRATORY UNAVAILABLE DIAGNOSIS OF TRANSFORMER Russian patent published in 2018 - IPC G01R31/06 

FIELD: electrical engineering.

SUBSTANCE: this invention relates to tests of a power transformer, and more particularly to a control of the sufficiency of the forces of pressing its windings, periodically conducted during operation to verify the preservation of the transformer electrodynamic resistance to short-circuit currents. Design of the transformer is mechanically impulsively affected, the EMFs induced in its phase windings are measured and the frequencies of the maximum power spectral density (SPM) of the measured EMF are determined. Then, the frequencies of the SPM maxima in the phase windings of the transformer are compared, the smallest and largest of these frequencies are determined and their ratio is calculate. If this ratio is less than the threshold value, the transformer is decommissioned. At other values of this ratio, the diagnosis is continued and the transformer is left in service if the lowest frequency of the maximum of the SPM exceeds the boundary value, wherein said threshold and boundary values are selected depending on the values of the design stock of the short circuit current. Thehreshold value can be selected within 0.5÷0.6, and the boundary value is within where F is the initial force (in newtons) of the winding press, α – constant for a given type of transformer value (in N/Hz⁴).

EFFECT: increase of operational reliability of the transformers that passed the diagnosis and optimization of repair costs for the extension of their service life, as well as reducing the average time spent on assessing the technical condition of the transformers under test.

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