Cause analysis of transformer abnormal sound

Transformer noise is the inherent characteristics of transformer operation, the relevant national standards for its strict sound level limits, but with the improvement of user awareness of environmental protection, reflecting the transformer field noise is too large complaints are gradually increasing, and the reflected noise level is often larger than the factory test data, according to some on-site processing experience, the analysis has the following reasons.

1, the reason for the voltage problem: high voltage, will make the transformer overexcited, the sound increases and sharp, directly and seriously affect the transformer noise. Judgment method: First look at the low-voltage output voltage, can not look at the voltmeter on the low-voltage cabinet, the voltmeter only plays an indicative role, should use a more accurate multimeter for measurement. Solution: Now the 10KV voltage in the city is generally high, according to the output voltage of the low voltage side, then the tap file should be placed in the appropriate gear. Under the premise of ensuring the quality of low-voltage power supply, try to increase the high voltage tap (low voltage output voltage is reduced), so as to eliminate the over-excitation phenomenon of the transformer and reduce the noise of the transformer.

2, fan, shell, other parts of the resonance problem cause: fan, shell, other parts of the resonance will produce noise, generally mistaken for transformer noise. 1) Shell: press the shell aluminum plate (or steel plate) by hand to see if the noise changes, such as changes, the shell is in resonance. 2) Fan: Use a dry long stick to top the shell of each fan to see if the noise changes, such as changes, indicating that the fan is in resonance. 3) Other parts: Use a dry long stick to top each part of the transformer (such as: wheels, fan support, etc.) to see if the noise changes, such as changes that the parts are in resonance. Solution: 1) See whether the shell aluminum plate (or steel plate) is loose, it is possible to step on the deformation during installation, it is necessary to tighten the screw of the shell, fix the aluminum plate of the shell, and correct the deformed part. 2) To see whether the fan is loose, it is necessary to tighten the fastening bolts of the fan, and put a small piece of rubber between the fan and the fan support to solve the problem of fan vibration. 3) If the transformer parts are loose, they need to be fixed.

3. The reason for the installation problem: poor installation will exacerbate the transformer vibration and amplify the transformer noise. Judging methods: (1) The transformer foundation is not firm or uneven (an Angle hanging), or the bottom plate is too thin. (2) Using channel steel to frame the transformer will increase noise. Solution: (1) The installation unit will transform the original installation method. (2) The shock-proof rubber pad under the transformer car can solve some noise.

4, the installation environment of the impact of the reason: the operating environment affects the noise of the transformer, the adverse environment makes the transformer noise increased by 3dB ~ 7dB. Judgment method: 1) The transformer room is very large and very empty, there is no other equipment, there is an echo. 2) The transformer is too close to the wall, less than 1 meter. The transformer is placed at the corner, and the wall reflection noise is superimposed with the transformer noise to increase the noise. 3) The original use of oil change, dry change will affect the transformer noise. The reason is that the crude oil change chamber is relatively small, and there is an oil leak chamber and an oil leak hole, and the transformer is like placed on a speaker. Solution: Some sound-absorbing materials can be appropriately installed indoors. Goodbye, may we all become a better self in the time when we can't see each other.

5. The cause of the bus bridge vibration problem: due to the large current passing through the side-by-side bus, the bus vibrates due to the leakage magnetic field. The vibration of the bus bridge will seriously affect the noise of the transformer, so that the noise of the transformer increases by more than 15dB, which is difficult to judge, and the general user and installation unit will mistake it for the noise of the transformer. Judging method: (1) The noise changes with the load size. (2) Use a stick to force the busbar bridge, if the noise changes, it is considered that the busbar bridge is in resonance. (3) The bus bar vibrates in the bridge frame, and it is useless to use the stick top. You need to open the bus bridge cover to check whether the bus is fixed. Solution: (1) Mainly destroy the resonance conditions of the bus bridge, tighten or loosen the boom screws. (2) Open the bus bridge cover and fix the bus. (3) The low-voltage outlet is soft connected. 4) Ask the manufacturer of the bus bridge to solve it.

6. The reason for the resonance of the transformer core itself is that there is an electromagnetic attraction between the silicon steel sheet joints and the laminates due to magnetic leakage. Judgment method: (1) transformer noise is too large, normal noise mixed with other noise.(2) The transformer noise is wavy. Solution: (1) Tighten the screws on the transformer, including the two screws of the clamp, the core screws, and the pad pressing screw. (2) Add shock-proof rubber pad under the transformer car to solve some noise.

7. The reason for the resonance of the transformer coil itself: when the load current passes through the winding, the magnetic leakage generated by the load current causes the vibration of the winding. Judgment method: (1) transformer noise is too large, the noise is relatively low. (2) When the load of the transformer reaches a certain level, noise begins to appear, and sometimes there is no phenomenon. Solution: (1) Tighten all the pad pressing screw and increase the axial pressing force of the coil. (2) Loosen all the cushion pressing screws, loosen all the bolts on the outlet copper bar and the neutral copper bar, shake the low-voltage coil, shift the high-voltage coil 3 ~ 5 mm, and then tighten all the bolts.

8, the reason for the problem of load nature: the voltage waveform of the transformer is distorted (such as resonance phenomenon), and noise is generated. Judging method: (1) In addition to the noise of the transformer itself, there is also a "cluck, cluck" noise. (2) In the process of operation, the transformer noise will immediately become sharply larger, and soon return to normal. (3) Check whether there is rectification equipment and frequency conversion equipment in the load. Solution: Users can consider installing devices to reduce harmonics.

9, transformer phase problem cause: the transformer can not be excited normally, produce noise. Solution: 1) transformer power failure, check whether the power supply is missing a phase; 2) Check whether the transformer high voltage fuse is blown.

10, the reason for the poor contact: First, due to the poor contact in the high pressure cabinet. The second is that the brake is not closed in place: the transformer makes intermittent abnormal noise. Solution: 1) Check the contacts and fuses of the high voltage cabinet and the entire high voltage circuit. 2) Ask the high pressure cabinet manufacturer to check.

11, the reason for the suspension potential problem: the transformer clip channel steel, pressure bolt, pull plate and other parts are sprayed with blue paint, the parts contact is not very good, under the action of leakage magnetic field between the parts to produce suspension potential discharge sound. Judgment method: Suspension potential discharge emits a very slight "squeak, squeak" sound, listen carefully to hear, the user is often mistaken for transformer high voltage or low voltage discharge. Solution: (1) This discharge will not affect the normal operation of the transformer. (2) The paint in the bad contact position can be scraped off during power outage maintenance, so that the parts of the transformer are in good contact.

12, the low-voltage line is grounded or short-circuit: when the low-voltage line is grounded or short-circuit accident, the transformer will emit a roaring sound; The closer the short circuit point is to the transformer, the more obvious the sound is. If the short circuit point is near the transformer, the transformer will make a roar like a tiger.     

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