Discrimination and analysis of abnormal sound of transformer when the transformer is in normal operation, it will emit average and continuous AC electric sound under normal conditions. If send out abnormal sound, it is internal spark discharge commonly, or external attack instantaneous short circuit wait for a condition. Transformer sound than usual increase and average sound: may be the power grid single-phase grounding or resonance, the occurrence of overvoltage.

When single-phase grounding or resonant overvoltage occurs in power grid, the sound of transformer will increase, and the sound of transformer is sharper than usual. In this case, the indication of separable voltmeter will stop comprehensive discrimination. It may also be that when the transformer is overloaded, when the transformer is loaded with electric arc furnace, silicon controlled rectifier, etc., due to the harmonic weight.

Therefore, the transformer will make a "Whoa" or "cluck" intermittent sound. If it is found that the load of the transformer exceeds the allowable normal overload value, the transformer load should be reduced according to the rules of the site regulations. The sound of transformer increases unevenly: when the power equipment with large capacity starts, the load changes greatly, which makes the sound of transformer increase. For example, when ferromagnetic resonance occurs in the system, the transformer will produce uneven noise.

There is discharge sound in transformer: it indicates that the porcelain parts are seriously polluted or the line card of the equipment is in poor contact, and there is discharge sound in transformer. If there is blue corona or spark near the transformer bushing at night or in rainy weather. The internal contact is poor, or the insulation is broken down. If the internal discharge of the transformer occurs, it is the electrostatic discharge of ungrounded parts or coil turn to turn discharge, or due to the poor contact of the tap changer, the sound of the transformer is "crackle, squeak", and the sound changes with the distance of the fault point. At this time, the transformer should be further detected or stopped.