针对某500 kV变电站5052电流互感器发生放电烧蚀故障的问题,从主要化学成分、断口形貌、显微组织、显微硬度、能谱分析等方面对其故障原因进行分析。结果表明:互感器爆破片拱面在运输或组装过程中受到碰压损伤,使得爆破片的爆破压力和稳定性明显降低;互感器在正常工况下运行3 a后,爆破片拱面发生失稳反转爆破,并沿减弱槽开裂,导致SF₆泄漏,降低了互感器的绝缘性,进而发生放电烧蚀故障。

Aiming at the discharge ablation fault of 5052 current transformer in a 500 kV substation, the causes of the fault were analyzed from the aspects of main chemical composition, fracture morphology, microstructure, microhardness and energy spectrum analysis. The results show that the arch surface of the transformer blasting piece was damaged by collision pressure during transportation or assembly, which made the blasting pressure and stability of the blasting piece significantly reduced. After the transformer operated under normal working conditions for three years, the arch surface of the blasting slice underwent instability reverse blasting, and cracking along the weakening groove, resulted in SF₆ leakage, reduced the insulation of the transformer, and then the discharge ablation fault occured.