Five main preventive measures for transformer bushing damage

Five main preventive measures for transformer bushing damage

(1) Transformer bushing manufacturers should improve their level of process quality inspection management to avoid loose insulation paper wrapping, serious creases, and discharge along the creases; To avoid errors in the size of the capacitive screen, which can cause electric field concentration at the end of the capacitive screen, form dendritic discharge, damage insulation, and cause breakdown and explosion.

(2) According to the provisions of the Regulations on Preventive Attempts of Power Equipment, serious attempts should be made, with special attention paid to the changes in dielectric loss angle, capacitance, and chromatographic analysis results. It is not only necessary to consider the absolute value of the attempt results, but also to study the relative changes in the results of previous attempts, so as to promptly identify problems and handle them to avoid damage.

(3) Any oil leakage defects should be dealt with immediately, and the contact heating of the transformer bushing lead terminals should be detected in a timely manner.

(4) The vacuum drying treatment of transformer bushing in manufacturing must be thorough, otherwise there are residual bubbles in the insulation. Under the action of the electric field, these bubbles have to withstand higher electric field strength than solid insulation and produce partial discharge. The discharge continues to spread and develop under long-term occupational voltage, damaging the insulation. If there is residual moisture, the heat emitted from the insulation will exceed the heat distributed to the surrounding area, and the insulation temperature will continue to rise, resulting in heat instability, This leads to thermal breakdown.

(5) For old and unreliable transformers and those that fail attempts, they should be dealt with as soon as possible. If dismantling and repair are to be carried out, vacuum oiling should be carried out after the assembly of the transformer bushing. The vacuum degree and pumping time should be suitable for the manufacturer's request. After repair, dielectric loss and partial discharge tests should be conducted under high voltage.