以±800 kV云广特高压直流输电工程穗东换流站干式平波电抗器树枝状放电故障为例，根据对现场设备的检查情况和三维电磁场软件计算结果，分析了这次故障发生的原因，指出特高压直流工程中平波电抗器设计存在的不足，并提出了相应的改进措施和运行维护建议。

Taking the tree discharge fault of dry-type smoothing reactors in Suidong converter station of ± 800 kV Yunnan-Guangdong UHVDC transmission project as example, the reason of the accident was analyzed, based on the equipment inspection and the calculation results of 3D electromagnetic field software. The results show that there are some deficiencies of the design of smoothing reactor in the UHVDC transmission project. So this paper put forward the improvement measures and some suggestions for operation and maintenance.