power transformer

The expounded method of impulsive expose of defect of power transformer at excitation in him of damped oscillations by the periodic impulses of constant voltage. On the size of change of parameters of these vibrations at exploitation of transformer it is possible to estimate the origin of defects by the periodic diagnosticating and comparison of defectograms with normograms and to forecast development of defects and define possibility of after exploitation of transformer without the necessity of permanent or capital repair.

Resonance voltage of one of the natural resonant frequency progresses in power transformer windings when they are under the influence of pulse overvoltage. The amplitude of free oscillating voltage and the amplitude of the pulse voltage are commensurable, but the existence time of oscillation lasts tenfold longer than the existence time of pulse voltage does. The overvoltage may cause coil faults. Overvoltage limiter installation is the main issue of reliability improvement in 110 kV or less power supply system.