I. Loose Iron Core: The "Primary Suspect" of Abnormal Noise
Abnormal Characteristics: The buzzing sound is accompanied by irregular "clicking" or metallic collision sounds, and the vibration sensation increases.
Self-check Steps:
After powering off, check whether the iron core clamping bolts are loose (professional protective operation is required).
Observe whether there are rust or insulation paint peeling marks on the surface of the iron core.
Use an infrared thermometer to detect whether there is local overheating in the iron core (be vigilant if the temperature difference is > 15°C).
Response Suggestions: Immediately shut down the transformer and contact a professional to tighten or replace the insulating materials to avoid short circuits caused by multiple grounding points of the iron core.
II. Winding Fault: The Potential Crisis of High-frequency Abnormal Noise
Abnormal Characteristics: The sound changes to a high-frequency "hissing" or popping sound, and there may be a burnt smell.
Self-check Clues:
Check whether the load suddenly increases, leading to overcurrent in the windings.
Observe whether there are discharge marks on the bushings and terminal blocks.
Measure whether the three-phase currents are seriously unbalanced using a clamp meter.
Risk Warning: Inter-turn short circuits in the windings may cause a fire. If the abnormal noise persists, emergency power off and troubleshooting are required.
III. Overload Operation: The Dull "Overwork Alarm"
Abnormal Characteristics: The buzzing sound is dull and continuously increases, and the temperature rises sharply.
Quick Diagnosis:
Check the rated capacity on the transformer nameplate against the actual load (it is recommended that the load rate ≤ 80%).
Check the cooling system (oil level, whether the fans/heat sinks are blocked).
Record the peak load periods to determine whether it is a temporary overload or a long-term design deficiency.
Optimization Plan: Adjust the load distribution, install a temperature-controlled fan, or consider capacity expansion and renovation.
IV. Insulation Aging: The "Dangerous Signal" in Humid Weather
Abnormal Characteristics: The noise increases significantly in rainy and humid weather, accompanied by local discharge sounds.
Self-check Key Points:
Check the oil level and color of the oil-immersed transformer (if the oil is turbid or black, it needs to be tested).
For dry-type transformers, observe whether the epoxy resin surface is cracked or dusty.
Use an insulation resistance tester to detect the resistance value between the windings and the ground (be vigilant if it is less than 50% of the initial value).
Maintenance Suggestions: Regularly conduct chromatographic analysis of the insulating oil, and it is recommended to install a dehumidifier in a humid environment.
V. Interference from External Factors: The "Invisible Pusher" Easily Overlooked
Common Inducing Factors:
Resonance: Peripheral equipment (such as air conditioning units) coincides with the natural frequency of the transformer.
Intrusion of Foreign Objects: Bolts, bird nests, etc. cause mechanical vibrations.
Voltage Distortion: Non-linear loads (frequency converters, arc furnaces) lead to harmonic pollution.
Investigation Methods:
Test the no-load operation to determine whether the noise comes from the transformer itself.
Use a harmonic analyzer to detect the power grid quality (treatment is required if THDv > 5%).
Check whether the installation foundation is level and whether the shock-absorbing rubber pads are aged.
Safety Tips and Professional Services
⚠️ Self-check Precautions:
Be sure to cut off the power and test for electricity before operation, and wear insulating protective equipment.
Only basic appearance inspections are recommended, and internal faults need to be handled by a certified engineer.
If you still cannot determine the source of the fault through the above steps, or if you find emergency situations such as oil leakage or smoking, please contact a professional team immediately. XX Power Service provides:
✅ 24-hour emergency repair
✅ Accurate diagnosis using infrared thermography
✅ Laboratory testing of insulating oil
✅ Harmonic control and energy-saving renovation