Will Overload Operation Cause Permanent Damage to Oil-Immersed Transformers?

Short-term overload within standard allowable limits generally does not cause permanent damage.However,prolonged overload,frequent repeated overload,or severe overload beyond specified time and temperature thresholds will lead to irreversible permanent damage and shorten the overall service life drastically.

When a transformer runs overloaded,the load current increases sharply,producing extra copper loss and raising the temperature of windings,insulating paper and mineral oil.According to the 6°C rule,every 6°C rise of winding hot-spot temperature will approximately double the aging rate of solid insulation.

Moderate short-term overload(within IEC and GB standard limits)

Temporary overload during peak power demand is permitted.The temperature rise is controlled within the safe range,and insulation materials will only experience slight accelerated aging without permanent structural damage.The transformer can return to normal working condition after the load drops.

Long-term continuous overload or frequent cyclic overload

Persistent high temperature gradually carbonizes insulating paper,reduces mechanical strength and insulation performance.The insulating oil will oxidize,produce acid substances and sludge,which further corrodes internal components.These changes are irreversible,resulting in permanent degradation of insulation and hidden faults such as partial discharge.

Severe emergency overload exceeding limits

Extreme overload causes winding hot-spot temperature to surge rapidly.It may directly burn insulation,deform windings,melt contacts or trigger internal short circuits.Such accidents bring direct permanent damage and even lead to transformer scrapping.

In summary,overload is a major threat to oil-immersed transformers.Operators must strictly follow loading guidelines to avoid long-term or excessive overload for long-term reliable operation.

References

APA 7th Edition

Li,Y.,&Zhang,H.(2023).Overload capacity analysis and aging mechanism of oil-immersed distribution transformers.IEEE Access,11,124512-124520.

MLA 9th Edition

Li,Yu,and Hong Zhang."Overload Capacity Analysis and Aging Mechanism of Oil-Immersed Distribution Transformers."IEEE Access,vol.11,2023,pp.124512-124520,

IEEE Style

Y.Li and H.Zhang,"Overload capacity analysis and aging mechanism of oil-immersed distribution transformers,"IEEE Access,vol.11,pp.124512-124520,2023,