某特高压变电站一台高端△接换流变压器的冷却器发生漏油。将冷却器解体检查后发现其内部3003铝合金导油管存在大量渗透点。运用体视显微镜、光学显微镜、光谱仪、SEM，EDS等技术对铝合金导油管漏油的原因进行了分析。结果表明：铝合金导油管的内表面存在数个腐蚀坑，腐蚀产物含有较高浓度的Cl、S等典型腐蚀元素。腐蚀过程使得铝合金管的壁厚不断减薄，最终在厚度方向上贯穿整根铝合金管，导致油品渗漏。

The cooler of a converter transfomer located in an extra-high voltage substation leaked oil. After inspecting the cooler, it was found that a large number of leakage points distributed in 3003 aluminum alloy oil pipes. Stereomicroscopy, optical microscopy, spectrography, SEM, EDS and other techniques were adopted to analyze the reasons causing leakage of the oil pipe. Results indicate that there were several corrosion pits on the inner surface of the aluminum alloy pipes, and the corrosion products contain high concentration of S element and Cl element. The corrosion process made the thickness of aluminum alloy pipes thin. Eventually, the aluminum alloy pipes were totally corroded in the direction of thickness, which resulted in the oil leakage.