What is transformer winding deformation?
Transformer winding deformation refers to the irreversible change in the size and shape of the winding due to mechanical force and electromotive force. It includes changes in axial and radial dimensions, body displacement, winding twists, bulging, and inter-turn short circuits. The reason is that it is inevitable that the transformer has to withstand various short-circuit impacts during operation, and the outlet short-circuit is particularly harmful to the transformer.
Although the circuit breaker can quickly remove the short-circuit fault from the circuit, the automatic device often does not operate for some reason, so that the transformer coil will deform in a short time under the action of the short-circuit current heat and electromotive force, and it may even be serious. It will cause a short circuit between phases and burn out the windings. At the same time, the transformer may also be subject to impact and impact during transportation and installation, resulting in distortion, strand breakage, migration, and loosening.
What is the purpose of conducting transformer winding deformation test?
Answer: Winding deformation is a major hidden danger to the safe operation of power systems. In recent years, as the capacity of the power system has grown, the short-circuit capacity has also increased, and the number of winding damage accidents after export short-circuits has also increased.
After the transformer winding is deformed, firstly, the insulation distance changes or the insulation paper is damaged. When an overvoltage occurs, the winding will break down between the pie or the turn, or under the action of long-term working voltage, the insulation damage will gradually expand, which will eventually lead to the transformer Damage: Second, after the winding is deformed, the mechanical performance decreases. When a short-circuit accident occurs again, an immediate damage accident will occur due to the inability to withstand the huge impact force, and more often it can still run for a period of time.
Transformer winding deformation is one of the important reasons for transformer damage accidents. Conventional electrical tests such as resistance measurement, transformation ratio measurement and capacitance measurement are difficult to find winding deformation, which will seriously threaten the safe operation of the power grid. For this reason, it is very necessary to test and diagnose the winding deformation of the transformer that has been subjected to mechanical force and electrodynamic force.