What are the causes of transformer noise?The sound power of any mechanical vibration is determined by the rate at which the noise source radiates energy. Flow rate must be described in terms of direction, so sound intensity is a vector, whereas sound pressure is a scalar, with only magnitude and no direction. Most transformer noise measurements can be done with ordinary microphones, which measure sound pressure only.
The sound pressure heard by the human ear, or the sound pressure measured by a microphone, is only the sound power radiated by the source of sound. It represents the noise level of the sound source. unique parameters. Sound propagates in the air like ripples in a pond. The farther away from the sound source, the smaller the sound wave amplitude. This only applies to sound propagation paths without obstacles. During sound propagation, part of the sound will be reflected, part will be absorbed, and the rest will be transmitted. An object’s properties, size, and wavelength affect the amount of sound reflected, absorbed or transmitted by it. Predicting or changing the sound pressure of a single vibrating mechanical surface requires knowledge of the object and its surroundings.
During operation, the transformer will emit noise. Despite the fact that this kind of noise can be annoying to some people, it is difficult to solve for a variety of reasons, the main reasons being:
- Transformers are often located closer to homes and offices than other equipment
- During the night, when the transformer is running continuously, the continuous noise is most noticeable
There are three sources of sound in the transformer: the iron core, the winding, and the cooler; In addition to transformer noise generated by no-load and load systems, transformer noise is also generated by cooling systems.
- Under the action of the alternating magnetic field, the silicon steel sheet that constitutes the iron core undergoes a slight change, known as magnetostriction, and the magnetostriction causes the iron core to periodically vibrate with the change in the excitation frequency.
- Winding vibration occurs because current generates an electromagnetic force in the winding, and leakage magnetic fields can also cause the structure to vibrate. The electromagnetic force (and vibration amplitude) are positive with square of current.
- There is a clear relationship between the transmitted power and the load current.
The following are some of the causes of abnormal noise in transformers as well as solutions to it:
| The phenomenon of faults | Concerning the equipment and parts | Causes likely to be at fault | Problem-solving |
| Noise that is abnormal | Shell of metal | It is shocking | All equipment should be checked and inlaid panels should be fastened |
| Noise that is abnormal | The bus bar | It is shocking | Secure inlay panels and check equipment |
| Noise that is abnormal | Core | During transportation and operation, the iron core is deflected by shock | Measure the noise level and the mechanical condition of the transformer |
| Noise that is abnormal | Plate of rating | It is shocking | The spacer should be checked and the offset coil should be adjusted |
| Noise that is abnormal | Board for non-excitation voltage regulating taps | There is a problem with the connection board | Equipment should be checked |
| Noise that is abnormal | Networking | The network voltage is too high and the harmonic content is too high | Make sure the breakout board is positioned according to the voltage on the network |
