The transformer will continue to deliver power even when its internal temperatures are rising dangerously. High temperatures contribute to faster insulation aging and reduce equipment dependability, leading to possible equipment failure.
There are several factors that affect the temperature of the transformer during power distribution. These include electrical loading, ambient temperature, effectiveness of cooling, and state of the insulating materials. At Mahendra Transformers, we help you learn about these factors as transformer manufacturers.
Warning Signs of Transformer Overheating:
Transformer overheating does not always produce visible smoke or a burning smell. There are many cases where changes in operating conditions provide the earliest warning.
- Abnormal Temperature Indicators: An abnormal increase in temperature in the oil and windings above the manufacturer’s limit calls for an immediate inspection. This unusual situation, even before the alarm triggers, is worth investigating.
- Temperature alarm warnings: The continuous warning is indicative of overload, cooling system failure, or lack of adequate cooling.
- Noise or vibration: The change in the humming noise will indicate any electrical or mechanical problem requiring testing.
- Oil leakage or deterioration: For transformers that have oil as an insulating material, there could be oil leakage or deterioration.
- Local heating: Infrared imaging can be used to detect hot spots in the cable ends, bushings, and other components.
What Causes Transformer Overheating?
Understanding the underlying causes is essential for effective transformer maintenance.
1. Overheating due to Excessive Electrical Loading:
The transformer coils have resistance; therefore, they generate heat. With an increase in loading, the loss due to heating is proportional to the square of the load.
2. Increased Ambient Temperatures:
Transformers need to dissipate the heat generated inside the transformer to the surrounding environment. With high ambient temperatures, the temperature difference required for cooling is reduced.
3. Cooling system failure:
The oil-filled transformers use oil as an insulating medium for the purpose of conducting heat from the core and winding to radiators. Any blockage at the radiator surfaces, malfunctioning of cooling fans, pumps, or even poor airflow may lead to overheating of the transformers.
4. Insulation and oil deterioration:
Overheating is known to accelerate the aging process of the paper insulation that surrounds the windings of the transformers. When it comes to the case of oil-filled transformers, overheating causes oil oxidation.
Technical Checks That Help Detect Overheating Early:
| Maintenance check | What it helps identify |
| Oil and winding temperature monitoring | Abnormal heating trends and potential overload conditions |
| Infrared thermography | Localised hot spots at accessible connections and components |
| Insulating oil testing | Changes in oil quality, moisture, and dielectric strength |
| Dissolved gas analysis (DGA) | Certain developing internal faults indicated by gases generated in transformer oil |
| Load and phase-balance assessment | Excessive loading and uneven distribution of electrical demand |
Practical Transformer Maintenance Tips:
- Monitor temperatures and examine any abnormality rather than awaiting a shutdown.
- Maintain the cleanliness of radiators, cooling fans, and the ventilation areas.
- Check electrical connections and conduct thermographic examinations at appropriate times.
- Conduct tests on transformer oil based on the equipment condition and manufacturer’s recommendation.
Conclusion:
Overheating of the transformer can be detected even before any harm is done to the equipment. This is made possible through monitoring the temperature, testing the oil, evaluating the loads, and testing the cooling systems. Choose the Mahendra Transformers for best manufacturing and services.
