Oil-immersed transformers play a critical role in ensuring stable power transmission in electrical systems. However, after long-term operation, these transformers may suffer from oil leakage, which not only wastes transformer oil but also reduces insulation performance, increases overheating risks, and can even trigger fires. This comprehensive guide will explain the common causes, fault symptoms, repair methods, and preventive measures for oil leakage in oil-immersed transformers.
Common Causes of Oil Leakage in Oil-Immersed Transformers
Aging seals: Seals such as rubber gaskets and sealants deteriorate over time due to prolonged exposure to heat and oil. Aging causes them to harden, lose elasticity, and fail, allowing transformer oil to seep through gaps.
Welding defects: Substandard welding during manufacturing can leave sand holes, pores, or weak joints. Over time, internal pressure expands these flaws, leading to oil leakage through the welds.
External mechanical damage: During transport, installation, or due to impacts in operation, cracks or deformations may form in the transformer tank and pipelines, causing oil leaks. Natural disasters like earthquakes and high winds can also induce such damage.
Frequent temperature fluctuations: Oil temperature rises and falls with the transformer load. Repeated expansion and contraction of seals under varying pressure accelerates aging and weakens tank joints, eventually leading to leaks.
Common Fault Symptoms of Transformer Oil Leakage
Oil stains on tank welds: Visible oil stains, often darkened by dust accumulation, appear at weld seams. Over time, these stains spread and may lead to oil drips.
Leakage at bushing roots: When seals at the base of the bushings deteriorate, oil stains form and oil may flow along the bushing, potentially compromising insulation and causing discharge failures.
Leaks at valve and flange joints: Damaged gaskets or loose bolts at valves and flanges result in noticeable oil stains. These areas often feel greasy to the touch.
Radiator oil seepage: Cracks or poorly sealed interfaces in the radiator cause oil stains and, in severe cases, oil drips. This reduces cooling efficiency and raises transformer temperatures.
Effective Repair Methods for Transformer Oil Leaks
Seal replacement: Replacing aged seals is a direct and effective fix. After draining transformer oil, disassemble relevant parts, clean sealing surfaces, and install new, high-quality seals with proper torque to ensure tight sealing.
Repair welding: For leaks due to welding defects, thoroughly clean and weld the affected area after draining oil. Small holes can be fixed with arc welding, while larger cracks require grinding and layered welding. Post-weld inspection is crucial to prevent recurrence.
Fixing external damage: Assess the extent of damage. Minor cracks can be repaired with metal repair agents, while severe damage requires component replacement. Always use materials that match original specifications for secure sealing.
Adjusting operational parameters: Reduce oil temperature fluctuations by managing transformer load carefully. Monitor oil temperature and optimize cooling system performance to minimize seal stress and potential leaks.
Preventive Measures to Avoid Transformer Oil Leakage
Routine maintenance and inspection: Conduct thorough inspections every six to twelve months. Check seal conditions, weld integrity, and the tightness of valve and flange joints. Address potential leak risks promptly.
Enhanced operational management: Operate transformers within recommended parameters. Avoid frequent startups and sudden load changes that stress equipment and increase the risk of oil leakage.
Selecting high-quality equipment and components: Invest in transformers and parts from reputable manufacturers. Superior materials and craftsmanship reduce fault occurrences and enhance long-term reliability.
Oil leakage in oil-immersed transformers is a serious issue that demands timely diagnosis and proper repair methods. By implementing preventive maintenance and using high-quality components, you can ensure the safe, efficient, and stable operation of your power system. For expert transformer maintenance services and quality components, contact us today to safeguard your equipment.
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