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Common parts of transformer short-circuit damage

time:2021/7/27   source:华天电力  reading:290 time

Transformer short-circuit is a very troublesome question. Today we will summarize the common parts of transformer short-circuit damage.


1. For the position under the iron yoke


The reasons for the deformation of this position are: (1) The electric field generated by the short-circuit current is closed by the oil and the tank wall or the iron core. Because the magnetic resistance of the iron yoke is absolutely small, it is mostly closed between the oil circuit and the iron yoke, and the electric field is absolutely absolute. In the collection, the infrared thermal imager is an instrument that is practical for construction and inspections in the Sinopec industry. It can not only quickly scan and identify faulty areas that the naked eye can't detect, but also can be used to deal with handy problems and common preventive maintenance tasks. The electromagnetic force acting on the wire cake is also absolutely greater; (2) The gap between the inner winding set is too large or the iron core is not tightly bound, causing expansion and deformation on both sides of the iron core sheet, resulting in warping and deformation of the winding on the iron yoke side; (3) In terms of structure , The yoke is the least reliable for the axial compression of the entire transformer winding. The wire cake at this position is often difficult to reach the pre-tightening force of the corresponding part, so the wire cake at this position is the most easily deformed.


Transformer Capacity Load No-load Tester.png


2. Voltage regulation tapping sea area and the position corresponding to the remaining windings


This sea area is due to: (1) Ampere-turns are not misaligned so that the leakage field will spread the air balance of the splint, and the leakage electric field generated by the rated amplitude will generate the rated axial external force in the coil. The position of the force is always inconsistent with the force. The error is greater than the balance. The axial external force is the same as the axial internal force generated by the general amplitude flux leakage, which causes the line cake to bend to a vertical position and tighten the pad of the line cake. In addition, the force is also fully or completely It is transmitted to the iron yoke, trying to separate the core column, and the wire cake is deformed or overturned in the middle of the winding; (2) The wire cake at this position is trying to be out of adjustment in ampere turns or there should be an insulating interval in the tapping interval, which often needs to be increased. More spacers, thicker spacers have a dedicated transmission delay, so the impact on the line cake is also greater; (3) After the winding is set, it is not possible to ensure that the core internal resistance is surprisingly aligned, so that the ampere-turn is further deepened ; (4) After running for a period of time, the thicker cushion block has a larger expansion, one on the upper side will deepen the ampere-turn without losing adjustment, and the other upper side will be deepened when the short-circuit force is applied; (5) try to make the ampere-turn out of adjustment at the assumed time , The magnet wire in the tapping area uses narrower or smaller cross-section calipers, which has low resistance to short force.


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