某输油管道防腐蚀层的绝缘性能在投运多年后出现明显的劣化，原牺牲阳极阴极保护系统已经无法达到有效阴极保护。通过追加外加电流阴极保护系统对原阴极保护进行增强，对追加外加电流阴极保护前后的保护效果进行对比。结果表明：采用外加电流阴极保护系统对管道原有的牺牲阳极系统进行增强，可以恢复管道阴极保护的有效性。

The insulation performance of the anti-corrosion layer of an oil pipeline was significantly deteriorated after many years of operation, and the original sacrificial anode cathodic protection system could no longer achieve effective cathodic protection. The original cathodic protection was enhanced by adding an impressed current cathodic protection system, and the protection effects before and after the addition of impressed current cathodic protection were compared. The results showed that the use of an impressed current cathodic protection system to enhance the original sacrificial anode system of the pipeline could restore the effectiveness of the pipeline's cathodic protection.