The discharge phenomenon of dry-type transformer
The discharge phenomenon of dry-type transformer is a relatively important activity of dry-type transformer, but the frequent discharge phenomenon of dry-type transformer will make the function and performance of dry-type transformer continuously reduce. Partial discharge of dry-type transformers will cause many functions of the dry-type transformers to be lost. So what are the main reasons for the formation of partial discharges of dry-type transformers?
Because the insulators and metal bodies in dry-type transformers often have some sharp corners and burrs, the charge will be concentrated on the sharp corners or burrs under the effect of the electric field strength, resulting in high electric field strength of partial discharge of the dry-type transformer. Charging capacity is concentrated at sharp corners, causing discharge.
In the case of vacuum-cast epoxy-cast insulation dry-type transformer, if the process control is not good, there will be bubbles inside and partial discharge will occur. In epoxy insulators, there are usually some small air gaps, usually the dielectric constant of the bubbles. It is much lower than the insulator which causes the bubbles in the insulator to withstand much higher electric field strength than adjacent insulating materials, and it is easy to reach the breakdown level, so that the bubbles discharge first.
If the electrical connections between the electrical conductors are not well connected to each other and a discharge may occur which is the most serious of the metal suspension potentials.
Excessive air humidity, insufficient insulation strength of the conversion part, or dry-type transformer insulation damage during installation.Dry-type transformers have an excessively long idling time, the moisture content of the insulating material exceeds the standard, and the overall moisture will affect the partial discharge.
The dry type transformer insulation structure is too high in the design of the sandwich or turns, such as the irrational design of the insulation structure; if it is not the required fake material, choose the quality of the insulation material. The winding and drying and casting process levels are not in place; the assembly process The level is not well assembled, such as the production of high voltage and low voltage leads with burrs or distance will affect the increase in partial discharge.