1. Voltage problem

Reason: High voltage will cause the transformer to be over-excited and the sound will become louder and sharper, which will directly seriously affect the noise of the transformer.

Judgment method: First look at the low-voltage output voltage. Do not look at the voltmeter on the low-voltage cabinet. The voltmeter only serves as an indicator. A more accurate multimeter should be used for measurement.

Solution: The 10KV voltage in cities is generally high now. According to the output voltage of the low-voltage side, the tap gear should be placed in a suitable gear. On the premise of ensuring the quality of low-voltage power supply, try to adjust the high-voltage tap upward (low-voltage The output voltage is reduced), thereby eliminating the over-excitation phenomenon of the transformer and reducing the noise of the transformer.

2. Resonance problems of fans, casings, and other parts

Reason: The resonance of the fan, casing, and other parts will produce noise, which is generally mistaken for the noise of the transformer.

Judgment method:

1) Shell: Press the aluminum plate (or steel plate) of the shell with your hand to see if the noise changes. If it changes, it means the shell is resonating.

2) Fan: Use a dry long wooden stick to push the shell of each fan to see if the noise changes. If it changes, it means the fan is resonating.

3) Other parts: Use a dry long wooden stick to push each part of the transformer (such as wheels, fan brackets, etc.) to see if the noise changes. If it changes, it means the parts are resonating.

Solution:

1) Check whether the aluminum plate (or steel plate) of the shell is loose. It may be deformed during installation. You need to tighten the screws of the shell, fix the aluminum plate of the shell, and correct the deformed part.

2) Check whether the fan is loose. You need to tighten the fastening bolts of the fan and put a small piece of rubber between the fan and the fan bracket to solve the problem of fan vibration.

3) If the transformer parts are loose, they need to be fixed.

3. Installation problems

Reason: Improper installation will aggravate the vibration of the transformer and amplify the noise of the transformer.

Judgment method:

1) The foundation of the transformer is not solid or flat (one corner is suspended), or the base plate is too thin.

2) Using channel steel to set up the transformer will increase noise.

Solution:

1) The installation unit shall modify the original installation method.

2) Adding anti-vibration rubber pads under the transformer trolley can solve some of the noise.

4. Influence of installation environment

Reason: The operating environment affects the noise of the transformer. An unfavorable environment increases the noise of the transformer by 3dB~7dB.

Judgment method:

1) The transformer room is large and empty, with no other equipment and echo.

2) The transformer is too close to the wall, less than 1 meter. The transformer is placed at the corner, and the reflected noise from the wall superimposes the noise from the transformer, making the noise increase.

3) The original oil transformer was used, but the change to dry transformer will affect the noise of the transformer. The reason is that the oil transformer chamber is relatively small, and there is an oil leakage chamber and an oil leakage hole. The transformer is like being placed on a speaker.

Solution:

Some sound-absorbing materials can be appropriately installed indoors.

5. The problem of busbar bridge vibration

Reason: Because a large current flows through the side-by-side busbar, the leakage magnetic field causes the busbar to vibrate. The vibration of the busbar bridge will seriously affect the noise of the transformer, increasing the noise of the transformer by more than 15dB. It is difficult to judge. Generally, users and installation units will mistakenly think it is the noise of the transformer.

Judgment method:

1) The noise changes with the load size.

2) Use a wooden stick to push the busbar bridge. If the noise changes, it is considered that the busbar bridge is resonating.

3) The busbar is vibrating in the bridge, and it is useless to push it with a wooden stick. You need to open the busbar bridge cover and check whether the busbar is fixed properly.

Solution:

1) Mainly to destroy the resonance conditions of the busbar bridge, tighten or loosen the suspender screws.

2) Open the busbar bridge cover and secure the busbar.

3) The low-voltage outlet line adopts soft connection.

4) Ask the busbar bridge manufacturer to solve the problem.

6. The transformer core resonates with itself

Reason: There is electromagnetic attraction caused by magnetic flux leakage between the joints of silicon steel sheets and the laminations.

Judgment method:

1) The transformer noise is too loud, and the normal noise is mixed with other noises.

2) The transformer noise is wavy.

Solution:

1) Tighten the screws on the transformer, including the two-end screws of the clamp, the through screws, and the pad pressure screws.

2) Adding anti-vibration rubber pads under the transformer trolley can solve some of the noise.

7. Transformer coil self-resonance

Reason: When a load current passes through the winding, the magnetic leakage generated by the load current causes vibration of the winding.

Judgment method:

1) The transformer noise is too loud and the noise is relatively low.

2) When the load of the transformer reaches a certain level, noise begins to appear, sometimes appearing and disappearing.

Solution:

1) Tighten all the pad screws to increase the axial compression force of the coil.

2) Loosen all the screws on the spacer block, loosen all the bolts on the outlet copper bar and neutral line copper bar, shake the low-voltage coil, move the high-voltage coil 3 to 5 mm in translation, and then tighten all the bolts.

8. Problems with load properties

Reason: The voltage waveform of the transformer is distorted (such as resonance phenomenon) and generates noise.

Judgment method:

1) In addition to the noise of the transformer itself, the noise is also mixed with "clucking, clucking" noise.

2) During operation, the transformer noise will suddenly increase sharply, and then return to normal soon.

3) Check whether there is rectifier equipment and frequency conversion equipment in the load.

Solution:

Users may consider installing devices to reduce harmonics.

9. The cause of the transformer phase loss problem: the transformer cannot be excited normally and generates noise.

Solution:

1) The transformer has a power outage, check whether the power supply is missing one phase;

2) Check whether the high voltage fuse of the transformer is blown in one phase.

10. Problems with poor contact

reason:

1) Caused by poor contact in the high voltage cabinet.

2) The knife gate is not closed in place

Judgment method:

The transformer makes intermittent and abnormal noise.

Solution:

1) Check the contacts and fuses of the high-voltage cabinet and the entire high-voltage circuit.

2) Ask someone from the high-voltage cabinet manufacturer to check.

11. The problem of floating potential

reason:

The clamping channel steel, pressure nail bolts, pull plates and other parts of the transformer were all sprayed with blue paint. The contact between the parts was not very good. Under the action of the leakage magnetic field, floating potential discharges occurred between the parts and made noises.

Judgment method:

Suspension potential discharge makes a very slight "squeak, squeak" sound, which can only be heard if you listen carefully. Users often mistakenly think that the transformer is discharging high or low voltage.

Solution:

1) This discharge will not affect the normal operation of the transformer.

2) During power outage and maintenance, the paint on the poor contact location can be scraped off to ensure good contact between the various parts of the transformer.

12. The low-voltage line is grounded or short-circuited.

When a low-voltage line is grounded or a short-circuit accident occurs, the transformer will make a roaring sound; the closer the short-circuit point is to the transformer, the more obvious the sound will be; if the short-circuit point is close to the transformer, the transformer will make a roaring sound like a tiger.

XZTZ1050 Series Flexible Current Clamp Meter