Common fault analysis of the hottest distribution

Analysis of common faults of distribution transformer

(1) when the sound is large and noisy, it may be the problem of transformer core. For example, when the clamp or the screw pressing the iron core is loose, the indication of the instrument is generally normal, and the color, temperature and oil level of the insulating oil do not change greatly. At this time, the operation of the insulation aging transformer should be stopped for inspection

(2) there is a boiling sound of water in the sound, and a "gurgling" bubble escape sound is emitted. It may be that there is a serious fault in the winding, causing the nearby parts to heat seriously and vaporize the oil. This kind of sound will be made when the tap changer is in poor contact and there is serious overheating at some points or transformer turn to turn short circuit. At this time, the operation of the transformer should be stopped immediately for maintenance

(3) when there is a loud and uneven explosion sound in the sound, it may be that the insulation of the transformer body has a breakdown phenomenon. At this time, the transformer should be stopped for maintenance

(4) when there is a "squeak" sound of discharge in the sound, it may be the partial discharge on the surface of the transformer body or bushing. If it is the problem of the casing, corona glow or small blue and purple sparks can also be seen in bad weather or at night. At this time, the dirt on the surface of the casing should be cleaned and then coated with silicone oil or silicone grease. At this time, stop the transformer and check whether the distance between the iron core grounding and the grounding of each live part meets the requirements

(5) when there is a continuous and regular impact or friction sound in the sound, it may be that some parts of the transformer are in mechanical contact due to the vibration of the iron core, or the other parts are made of flax and wheat straw fibers into particles. It is because of the abnormal sound caused by electrostatic discharge, and the indications of various gauges and temperatures have no response. Although this kind of sound is abnormal, it is not harmful to the operation, so it is not necessary to stop the operation immediately, It can be excluded during planned maintenance

2 abnormal temperature

when the load, heat dissipation conditions and ambient temperature of the transformer are unchanged, the temperature is higher than the original temperature under the same conditions, and has a rising trend. Jinan assaying is well-known, and it is also an abnormal increase in transformer temperature, which is also a symbol of transformer failure as well as the increase in over limit temperature

the causes of abnormal temperature rise are:

① transformer turn to turn, layer to layer, strand to strand short circuit

② partial short circuit of transformer core

③ heating of oil tank and cover caused by magnetic leakage or eddy current

④ long term overload operation and accident overload

⑤ deterioration of heat dissipation conditions, etc

if the temperature of the transformer is abnormal during operation, the reason should be found out first, then the driver should be explained to be damaged, and then corresponding measures should be taken to eliminate and reduce the temperature. If it is caused by the internal fault of the transformer, the operation should be stopped for maintenance