Thermal diagnostics of oil-filled equipment under operating voltage

The article justifies the need for technical diagnostics of high-voltage insulation of electrical equipment under operating voltage. The thermal imaging monitoring method of equipment condition is considered in the document. It is shown that by means of rejection criterion (tgMEAS-tgPLANT) defects in an initial stage of development come to light. The efficiency of control of high-voltage paper-oil insulation under operating voltage has been experimentally proved. The analysis of the causes of damage to high-voltage bushings and current transformers of 500 kV, based on which it was revealed that local defects are characteristic, the development of which leads to either thermal breakdown or the appearance of partial discharges and electrical breakdown of the main insulation. Thermal imaging diagnostics of such equipment as, for example, high-voltage bushings, coupling capacitors and current transformers makes it possible to detect almost all possible defects in insulation and measure their insulation characteristics. The efficiency of thermal imaging monitoring of the state of electrical equipment under operating voltage is shown. The calculated tg values from thermal imaging measurements are more accurate, since the results of measurements with a thermal imager are not affected by electromagnetic interference.It has been concluded that it is possible to abandon several traditional methods of testing with shutdown and without electrical equipment.