Causes and Hazards of Transformer Overheating
Post Time: 2024-10-22 10:55:35
I. What Happens When a Transformer Overheats
Insulation Damage
Transformer overheating can degrade the insulation materials and reduce the insulation dielectric strength as well as mechanical integrity. According to IEC 354, at the hottest spot temperature of 140°C, gas bubbles form in oil, which may trigger either electrical discharges or transformer failure.
Impact on Lifespan
The transformer insulation is normally Class A, and the limit for winding insulation is generally 105°C. For rated load conditions, the hottest-spot temperature should remain below 98°C. According to the IEC, for every 6°C rise in temperature, insulation effective life in service is reduced by half.
Performance Decline
Overheating leads to inefficiency in transformers, which increases their failure rate and thus can affect the stability and safety of the whole supply system.
II. Causes of Transformer Overheating
Core Heating
Since the insulation damage of the core or overvoltage may occur, the eddy current loss and hysteresis loss will be overheated. Besides, heat generation is also related to the choice of core materials.
Poor Cooling
If cooling and ventilation have not been taken fully into consideration in the design and installation, failure in cooling the equipment will lead to overheating.
Short Circuits
During a short circuit, there is sometimes a very sharp increase in current, with heat being produced proportional to the square of this current. This can result in catastrophic increases in temperature, beyond the limit which the insulation structure can withstand.
Overloading
Exceeding rated values or using them for very long periods is a common factor in overheating.
Poor Connections
Loose connections, inadequate welding, or oxidation serve to enhance contact resistance. Copper-aluminum connections, because of their abnormal electric properties, tend to corrode with time and generate overheating.
III.How to Prevent Transformer Overheating
Proper Design and Material Selection
Design, manufacture, installation, use, and maintenance of transformer equipment correctly are the basic measures to prevent overheating. transformer manufacturers should be chosen with a good reputation;
Regular Maintenance and Inspection
Standard maintenance and checking, which includes checking the transformer’s operational status, insulation, cooling systems, and electrical connections, will handle the problems while they are still in their incipient stage.
Effective Cooling Systems
Cooling oil, fans, and other cooling equipment should be up and running, and auxiliaries may be installed if necessary.
Load Management
Avoid long continuous operation above rated capacities; provide adequate load distribution and install load-monitoring devices to obtain actual load conditions in real time.
Improved Ventilation Conditions
Provide good environmental ventilation around the transformer in order to reduce the adverse effect of high temperatures and humidity on the apparatus.
Connection Checks
Periodically check connections for looseness, oxidation, or corrosion that may increase the contact resistance.
Install Temperature Monitoring Devices
Installation of temperature sensors on the transformer to monitor the rise in temperature in real time and give an alarm when it exceeds the preset threshold limits.
Training of Operators
Train the operators to enhance their capacity to operate and maintain the transformer by responding correctly and promptly in case any thing goes wrong.
Ⅳ.Conclusion
The above-mentioned measures can reduce overheating of the transformer effectively and enable it to work safely and stably by their adoption. That not only prolongs the service life of the transformer but also raises the total reliability of the power system.