Dry type transformers are widely used in power transmission and distribution systems due to their safety, environmental protection and low maintenance characteristics. However, noise problems often occur during operation, which not only affects the working environment but also may indicate potential faults. Whether it is a 150 kva dry type transformer or a 500 kva dry type transformer, abnormal noise requires timely diagnosis and solution. As a professional manufacturer, JINSHANMEN TECHNOLOGY CO., LTD mainly produces oil immersed power transformers, dry-type power transformers, oil immersed three-dimensional coiled power transformers, dry-type three-dimensional coiled power transformers, mining explosion-proof dry-type transformers, mining explosion-proof mobile substations, amorphous alloy power transformers, on load capacity regulating power transformers, locomotive dry-type transformers, as well as prefabricated substations, modular substations, wind energy box type substations, high and low voltage switchgear and other transmission and distribution equipment. Based on rich industry experience, this article summarizes 7 types of fault judgment methods and corresponding solutions for dry type transformer noise, providing practical guidance for relevant practitioners.
01 Resonance Problems of Fans, Enclosures and Other Components
Cause
Resonance of fans, enclosures, and other components will generate noise, which is generally mistaken for transformer noise. This phenomenon is also common in both 150 kva dry type transformer and 500 kva dry type transformer.
Judgment Method
Enclosure: Press the aluminum plate (or steel plate) of the enclosure by hand to see if the noise changes. If there is a change, it indicates that the enclosure is resonating.
Fan: Use a dry long wooden stick to push the enclosure of each fan to see if the noise changes. If there is a change, it indicates that the fan is resonating.
Other components: Use a dry long wooden stick to push each component of the transformer (such as wheels, fan brackets, etc.) to see if the noise changes. If there is a change, it indicates that the component is resonating.
Solution
Check if the aluminum plate (or steel plate) of the enclosure is loose. It may be deformed by stepping during installation. Tighten the screws of the enclosure to fix the aluminum plate of the enclosure and correct the deformed part.
Check if the fan is loose. Tighten the fastening bolts of the fan and place a small piece of rubber between the fan and the fan bracket to solve the fan vibration problem.
If the transformer components are loose, they need to be fixed.
02 Installation Problems
Cause
Poor installation will aggravate transformer vibration and amplify transformer noise. Improper installation has a more obvious impact on the noise of 500 kva dry type transformer due to its larger capacity.
Judgment Method
The transformer foundation is not firm or flat (one corner is suspended), or the bottom plate is too thin.
Erecting the transformer with channel steel will increase noise.
Solution
The original installation method shall be modified by the installation unit.
Adding anti-vibration rubber pads under the transformer trolley can solve part of the noise problem, which is applicable to both 150 kva dry type transformer and 500 kva dry type transformer.
03 Impact of Installation Environment
Cause
The operating environment affects the noise of the transformer. An unfavorable environment can increase the noise of the transformer by 3dB ~ 7dB. This impact is universal for dry type transformers of different capacities.
Judgment Method
The transformer room is large and empty, with no other equipment, resulting in echoes.
The transformer is too close to the wall (less than 1 meter) or placed at a corner. The noise reflected by the wall overlaps with the transformer noise, increasing the overall noise.
Originally using oil-immersed transformers, replacing them with dry-type transformers will affect the noise. The reason is that the original oil-immersed transformer room is relatively narrow, with an oil leakage chamber and an oil leakage hole, making the transformer like being placed on a speaker.
Solution
Properly install some sound-absorbing materials indoors.
04 Vibration Problem of Busbar Bridge
Cause
Due to the large current passing through the side-by-side busbars, the busbars vibrate due to the leakage magnetic field. The vibration of the busbar bridge will seriously affect the noise of the transformer, increasing the noise by more than 15dB. This fault is relatively difficult to judge and is generally mistaken for transformer noise by users and installation units.
Judgment Method
Noise changes with the load size.
Push the busbar bridge hard with a wooden stick. If the noise changes, it is considered that the busbar bridge is resonating.
If the busbar vibrates inside the bridge, pushing with a wooden stick will not work. It is necessary to open the cover plate of the busbar bridge to check if the busbar is fixed properly.
Solution
The main method is to destroy the resonance conditions of the busbar bridge by tightening or loosening the hanger screws.
Open the cover plate of the busbar bridge and fix the busbar properly.
Adopt flexible connection for low-voltage outgoing lines.
Invite the manufacturer of the busbar bridge to solve the problem.
05 Transformer Core Self-Resonance
Cause
There is electromagnetic attraction caused by leakage magnetic field at the joints and between the laminations of silicon steel sheets. This is a common internal fault source of dry type transformers, including 150 kva dry type transformer.
Judgment Method
The transformer noise is relatively large, with other noises mixed in the normal noise.
The transformer noise is wavy.
Solution
Tighten the screws on the transformer, including the screws at both ends of the clamp, through screws and pad pressing screws.
Adding anti-vibration rubber pads under the transformer trolley can solve part of the noise problem.
06 Transformer Coil Self-Resonance
Cause
When load current passes through the winding, the leakage magnetic field generated by the load current causes vibration of the winding. This fault is more likely to occur in 500 kva dry type transformer under high load conditions.
Judgment Method
The transformer noise is relatively large and low-pitched.
When the load of the transformer reaches a certain level, noise begins to appear, and sometimes it appears intermittently.
Solution
Tighten all the pad pressing screws to increase the axial pressing force of the coil.
Loosen all the pad pressing screws, loosen all the bolts on the outgoing copper bar and neutral copper bar, shake the low-voltage coil, translate the high-voltage coil by 3 ~ 5 mm, and then tighten all the bolts.
07 Problems with Load Nature
Cause
It distorts the voltage waveform of the transformer (such as resonance phenomenon) and generates noise. This problem is often caused by non-linear loads in the power grid.
Judgment Method
In addition to the transformer's own noise, there is also a "crackling" noise mixed in.
During operation, the transformer noise may suddenly increase sharply and then return to normal soon.
Check if the load includes rectifying equipment and frequency conversion equipment.
Solution
Users can consider installing devices to reduce harmonics.
About JINSHANMEN TECHNOLOGY CO., LTD
The company mainly produces oil immersed power transformers, dry-type power transformers, oil immersed three-dimensional coiled power transformers, dry-type three-dimensional coiled power transformers, mining explosion-proof dry-type transformers, mining explosion-proof mobile substations, amorphous alloy power transformers, on load capacity regulating power transformers, locomotive dry-type transformers, as well as prefabricated substations, modular substations, wind energy box type substations, high and low voltage switchgear and other transmission and distribution equipment. With rich experience in the transformer industry and advanced production technology, we are committed to providing high-quality, reliable transmission and distribution equipment and technical solutions for global customers. Whether you need 150 kva dry type transformer, 500 kva dry type transformer or other types of transformers, we can meet your personalized needs.