1. The sound when there is a lack of phase

When the transformer has a phase loss, if the second phase is disconnected, there is still no sound when it is fed to the second phase, and there will be a sound when it is fed to the third phase; There are generally three reasons for the lack of phase:

①The power supply lacks one phase of electricity;

② One phase of transformer high-voltage fuse is blown;

③ Due to careless transportation of the transformer and thin high-voltage lead wires, the vibration disconnection (but not grounded) is caused.

2. The pressure regulating tap-changer is not in place or has poor contact

When the transformer is put into operation, if the tap changer is not in place, it will make a loud “chirp” sound, which will cause the high voltage fuse to blow if it is serious; if the tap changer is not in good contact, it will produce a slight “squeak” spark discharge sound , Once the load increases, it is possible to burn out the contacts of the tap changer. In this case, the power should be cut off and repaired in time.

3. Falling foreign matter and loosening of the through-hole screw

When the core-through screw for clamping the iron core of the transformer is loose, there are nut parts left on the iron core, or small metal objects fall into the transformer, the transformer will make a “jingling” knocking sound or a “huh…huh…” blowing sound And the sound of “squeaking” like a magnet attracting a small gasket, but the voltage, current and temperature of the transformer are normal. Such situations generally do not affect the normal operation of the transformer, and can be dealt with when the power fails.

4. Dirty and cracked transformer high-voltage bushings

When the high-voltage bushing of the transformer is dirty and the surface enamel falls off or is cracked, surface flashover will occur, and the sound of “hissing” or “chucking” can be heard, and sparks can be seen at night.

5. The core grounding of the transformer is disconnected

When the core of the transformer is disconnected from the ground, the transformer will produce a slight discharge sound of “snapping and stripping”.

6. Internal discharge

When you hear the crisp sound of “crackling” when the power is being transmitted, it is the discharge sound of the conductive lead wire passing through the air to the transformer shell; if you hear the dull “cracking” sound passing through the liquid, it is the conductor passing through the transformer oil to face the shell discharge sound. If the insulation distance is not enough, the power should be cut off and checked, and the insulation should be strengthened or an insulation partition should be added.

7. The external line is disconnected or short-circuited

When the line is disconnected at the connection of the wire or at the T junction, it is disconnected when it is windy, and arcs or sparks occur when it is in contact, then the transformer will make a cry like a frog; When the line is grounded or short-circuited, the transformer will make a “booming” sound; if the short-circuit point is close, the transformer will roar like a tiger.

8. Transformer overload

When the transformer is seriously overloaded, it will emit a low “hum” sound like a heavy-duty airplane.

9. The voltage is too high

When the power supply voltage is too high, the transformer will be overexcited, and the sound will increase and be sharp.

10. Winding short circuit

When the transformer winding is short-circuited between layers or turns and burns out, the transformer will make a “gurgling” sound of boiling water.

Noise caused by external structure of dry-type transformer and its solution

(1) Dry-type transformers generally have a fan cooling system, and the abnormal noise of dry-type transformers is often caused by the failure of the fan system. Fans mainly have the following three types of failure phenomena:

①When the fan is put into use, there is a sound of “crackling” metal impact. This is because there are foreign objects in the fan, and the foreign objects need to be cleaned at this time.

②When the fan is just started, it makes a friction sound and it continues continuously. This is a quality problem of the fan itself. The fan must be replaced to ensure the normal operation of the fan system.

(2) A transformer with a protection level of IP20 or IP40 has a casing device. The casing will also be the source of transformer noise. The transformer will vibrate during operation. If the casing is not fixed, it will cause the casing to vibrate, thereby Noise is generated, so when installing the casing, it is best to add rubber pads between the casing and the ground and between the casing and the transformer base to reduce the transmission of vibration sound.

(3) After entering the electric room, a “buzzing” sound can be heard in a certain direction of the transformer. This is the result of the superimposition of the sound waves generated by the transformer vibration through the reflection of the wall. This situation is quite special. The space of the electric room is related to the location of the transformer. At this time, the position of the transformer can be adjusted to reduce the noise, and some sound-absorbing materials can also be properly installed on the walls of the electric room.

(4) A bad floor or bracket at the transformer installation location will aggravate the vibration of the transformer and increase the noise of the transformer. The ground where some transformers are placed is not solid. At this time, you will find that the ground will vibrate, and you will feel the vibration when you stand next to it. If it is serious, you will see cracks on the ground. If this is the case, the position of the transformer must be reinforced to reduce noise.