What does interturn short circuit mean?

[LaGage]

Interturn short circuit refers to a fault that occurs between the same-phase coils in the stator end winding due to electromagnetic frequency doubling vibration, which causes insulation wear and damage to the coil, resulting in an interturn short circuit. In the initial stage of an interturn short circuit, only two conductors may come into contact due to insulation wear at the overlapping area. The circulating current generated in the short-circuited turns rapidly heats the coil, further damaging the insulation of adjacent conductors, increasing the number of short-circuited turns and expanding the fault. It is caused by the breakdown of insulation between turns. In transformer interturn short circuit faults, the number of short-circuited turns is generally small. During the fault, this part of the winding is short-circuited but still forms a closed coil, equivalent to creating a new "short-circuit transformer" with a high turns ratio NS. The remaining non-short-circuited part can be regarded as another transformer.