Abnormal sound of transformer (reactor)

Because the transformer core is composed of silicon steel sheets, there is a gap between the sheets. When the transformer is energized, alternating magnetic flux is generated in the iron core by exciting current, and the silicon steel sheet generates frequency doubling vibration under the action of lateral thrust and longitudinal traction. This vibration makes the surrounding air or oil vibrate and produces a "buzzing" sound. In addition, the leakage flux generated by the inner coil close to the core generates alternating suction force to the core, and the silicon steel sheets in the outermost two layers on both sides of the core column are easily subjected to this suction force to generate frequency doubling vibration if they are not fastened firmly. This suction is proportional to the square of the current, so the magnitude of this vibration is related to the current. During normal operation, the sound of transformer core should be uniform, and when there are other noises, the reasons should be carefully found.

1, overvoltage or overcurrent. The noise of the transformer increases, but it is still buzzing, and there is no noise. With the rapid change of load, there may be intermittent noise of "cut, cut, cut, cut" assault. The appearance of this sound and the pointer of the indicating instrument (ammeter and voltmeter) of the transformer act at the same time, which is easy to distinguish.

2. The screw clamping the iron core is loose. It presents amazing sounds of "hammering" and "windy", such as "jingling" and "whistling". But the indicating instruments are all normal, and the oil color, oil level and oil temperature are also normal.

3. transformer shell collided with other objects. This is because the vibration of the iron core inside the transformer causes the vibration of other parts, which makes the contact parts collide with each other. If the hose with the control line on the transformer collides with the shell or radiator, it will make a "rustling" sound, which has the characteristics of continuous long and intermittent, and there will be no abnormality in all parts of the transformer. At this time, you can find the sound source, press it with your hand or wooden stick on the loudest side, and listen to the change of the sound to judge.

4. Discharge caused by external climate influence. For example, in foggy and snowy days, corona discharge or glow discharge is caused at the bushing, resulting in "hissing" and "scoffing" sounds, and small blue sparks can be seen at night.

5, turn-to-turn short circuit. Due to the serious local heating at the short circuit, the local boiling of oil will make a "gurgling" sound similar to water boiling, which should be paid special attention to.

6, tap changer failure. Due to the poor contact of the tap changer, local heating can also cause the sound caused by the short circuit between turns of the coil.