On-site processing experience of dry-type transformer operating noise - News - Global IC Trade Starts Here Free Join

Transformer noise is a natural byproduct of operation, and national standards set strict limits on sound levels. However, as environmental awareness increases, more users are reporting excessive transformer noise at the site. In many cases, the noise level observed on-site is significantly higher than factory test data. Based on field experience, the electrician forum Ligong has analyzed several common causes that may contribute to this issue.

1. Voltage Issues

Cause: High voltage can cause over-excitation in the transformer, leading to increased and sharper noise. This directly affects the overall noise level.

Judgment: Check the low-voltage output voltage. A standard voltmeter may not be accurate enough; use a high-precision multimeter for measurement.

Solution: If the 10kV voltage in the city is too high, adjust the tap position on the high-voltage side to reduce the low-voltage output, which helps minimize over-excitation and noise.

2. Resonance from Fans or Enclosures

Cause: Vibration from fans or the outer casing can generate noise, often mistaken for transformer noise.

Judgment: Press the casing or fan with a wooden stick to see if the noise changes. If it does, resonance is likely occurring.

Solution: Tighten any loose components, add rubber pads between the fan and bracket, or fix deformed parts to reduce vibration.

3. Installation Problems

Cause: Poor installation can increase vibration and amplify noise.

Judgment: Check if the base is uneven or the bottom plate is too thin. Using channel steel frames might also increase noise.

Solution: Adjust the installation method, add shock-absorbing pads under the trolley, or ensure the base is stable and even.

4. Environmental Impact

Cause: The surrounding environment can influence noise levels, increasing them by up to 7dB.

Judgment: If the room is empty, the transformer is near a wall, or placed in a corner, echo and reflection may increase noise.

Solution: Add sound-absorbing materials to the room to reduce noise reflections.

5. Busbar Bridge Vibration

Cause: Large currents passing through busbars can cause vibration due to magnetic fields, greatly increasing noise.

Judgment: Noise changes with load or when pressing the busbar bridge with a stick. If it does, the bridge is likely vibrating.

Solution: Tighten screws, fix the busbar, and consider using soft connections for the low-voltage side.

6. Transformer Core Resonance

Cause: Magnetic flux leakage between silicon steel sheets can cause electromagnetic attraction and vibration.

Judgment: Unusual noise patterns or wavy sounds may indicate core resonance.

Solution: Tighten all screws, including clamp and spacer screws, and add shock-absorbing pads under the trolley.

7. Coil Resonance

Cause: Load current creates leakage fields that cause coil vibration.

Judgment: Excessive noise, especially at certain load levels, may indicate coil issues.

Solution: Increase axial pressure on the coils and adjust the position of the windings.

8. Load Characteristics

Cause: Non-linear loads like rectifiers or frequency converters can distort voltage waveforms and create noise.

Judgment: Noises like “giggle” or “cluck” may be present, along with sudden noise increases.

Solution: Consider adding harmonic filters to reduce noise caused by non-linear loads.

9. Phase Loss

Cause: Missing phase power can lead to improper excitation and noise.

Solution: Check for missing phases, blown fuses, or faulty connections in the high-voltage circuit.

10. Poor Contact Issues

Cause: Loose contacts or misaligned switches can cause intermittent noise.

Judgment: Intermittent abnormal noises may indicate contact problems.

Solution: Inspect and tighten all contacts, fuses, and high-voltage components.

11. Floating Potential Discharge

Cause: Painted metal parts may develop floating potentials due to poor contact and magnetic fields, causing small discharges.

Judgment: A faint “beep” or “bang” sound may be heard, often mistaken for high-voltage discharge.

Solution: During maintenance, scrape off paint in problematic areas to improve conductivity and reduce discharge.

12. Grounding or Short-Circuit Faults

Cause: A short-circuit or grounding on the low-voltage side can result in loud noises, especially if the fault is close to the transformer.

Solution: Immediately locate and repair the fault to prevent damage to the transformer.

13. Differences Between Transformers

Cause: Transformers from different manufacturers or with different designs may produce varying noise levels depending on their operating environment.

Solution: Understand that noise levels vary based on design and usage conditions, but do not necessarily affect performance.

14. Misunderstanding of Dry-Type Transformers

Cause: Some users who previously used oil-filled transformers may expect similar noise levels from dry-type models.

Solution: Oil-filled transformers are enclosed and insulated, reducing noise transmission. Dry-type transformers are exposed, so they tend to be noisier, but this is normal and does not affect quality.