This comprehensive article delves into the critical issues surrounding oil-immersed transformers, focusing on oil leakage, overheating, and the overheating of external lead joints. It dissects the underlying causes and offers a suite of practical and innovative solutions, including regular maintenance, seal replacement, and advanced monitoring techniques, to ensure the transformers operate safely and efficiently.
Transformers are the backbone of power transmission systems, converting voltage levels to facilitate the efficient distribution of electricity. Oil-immersed transformers, in particular, are widely used due to their superior cooling and insulation properties. However, they are not immune to operational challenges that can compromise their performance and safety. This article aims to provide a detailed analysis of these issues and propose robust strategies for their mitigation.
Problem 1: Oil Leakage in Oil-Immersed Transformers
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Oil leakage is a common problem that can lead to a significant reduction in the transformer's cooling capacity and insulation properties. It is crucial to identify the source of the leak promptly, as it can vary from minor seepage at the valves to more extensive leaks along the casing. In China, where this analysis is focused, the construction and materials used may differ from those in foreign transformers, potentially influencing the leakage points and severity.
Upon discovering a leak, it is imperative to first assess the oil level. If the oil is found to be low, it must be replenished to maintain the transformer's cooling and insulation capabilities. The replenishment process should be conducted with care to avoid introducing contaminants that could further degrade the oil's performance.
Processing Direction
a. Engage professional inspectors to swiftly pinpoint the location of the oil leakage.
b. Investigate the root cause of the leakage, whether it be faulty seals, damaged casing, or manufacturing defects.
c. Replace seals with high-quality components that are compatible with the transformer's operational environment.
d. For more extensive damage, field patch welding may be necessary. This process should be carefully controlled to avoid overheating and potential combustion or explosion risks.
e. In cases where rapid sealing is required, the application of carbon nanopolymer materials can provide a quick and effective solution.
f. For persistent or recurrent leaks, consider replacing the affected parts with new components designed to enhance durability and resistance to leakage.
Problem 2: Overheating Indicated by Thermometers
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Overheating is a critical concern for oil-immersed transformers, as it can lead to a decrease in efficiency and, in severe cases, cause catastrophic failures. The thermometer's readings provide a preliminary indication of potential overheating issues. However, it is essential to verify these readings and rule out external factors such as faulty thermometers or high ambient temperatures.
The oil temperature measured by the transformer's thermometer reflects only the top layer's temperature. To gain a comprehensive understanding of the heat distribution within the transformer, point thermometers should be used to measure temperatures at various points. This approach helps determine whether the overheating is localized or affects the entire transformer.
Treatment Direction
a. Conduct a thorough inspection of the cooler's operational status, including checking for blockages, leaks, and mechanical failures.
b. If the transformer is consistently overloaded, consider reducing the load or upgrading the transformer to a higher capacity model to meet current and future demands.
c. Implement a regular maintenance schedule that includes testing and inspection of the transformer's insulation materials for signs of aging or damage.
d. Replace any damaged parts with new components that are identical or compatible with the original specifications and models to ensure the transformer's continued healthy operation.
Problem 3: Overheating of External Lead Joints in Oil-Immersed Transformers
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The external lead joints of oil-immersed transformers are susceptible to overheating, which can result in severe consequences such as fires, damage to conductive rods, and even explosions. The heat generated can also accelerate the aging of seals, leading to oil seepage and potential flashover discharges during humid conditions. It is crucial to monitor these joints closely and implement strategies to prevent overheating.
Avoidance Direction
a. Enhance regular transformer inspections by incorporating advanced diagnostic techniques such as DC resistance measurement during power outages and the use of far-infrared thermometers.
b. Install metal sheets at transformer lead joints and utilize heat color cameras for automatic detection and alarm triggering to improve monitoring and response times.
c. Adopt correct connection processes that minimize resistance and the potential for heat buildup. This may involve the use of specialized tools and techniques to ensure optimal contact between components.
d. Introduce new special wire clamps designed to increase the contact surface area, thereby reducing contact resistance and the likelihood of overheating.
e. Avoid or minimize overload operations to prevent excessive heat generation and ensure that the transformer operates within its designed parameters.
f. Create a conducive heat dissipation environment by maintaining adequate clearance around the transformer and using cooling systems when necessary.
Conclusion
In conclusion, the safe and efficient operation of oil-immersed transformers hinges on a proactive approach to maintenance and the implementation of advanced monitoring and mitigation strategies. By addressing oil leakage, overheating, and external lead joint issues with diligence and innovation, we can enhance the reliability and longevity of these critical components of our power infrastructure.
