以云广特高压直流系统1起双极三阀组相继闭锁事故为基础，分析了事故发生经过和原因，介绍了云广特高压直流系统测量系统，对云广特高压直流测量系统遭受干扰的原因进行了深入分析，并通过仿真与实验证明了干扰的存在。根据仿真和试验结果，以及穗东换流站二次设备抗干扰存在的问题，提出了相应的改进措施。

The successive blocks of bipolar three valves manifold occur in Yunnan-Guangdong UHVDC system.In this paper,the process of the accident are analyzed and the electromagnetic interference of measuring system analyzed.It is proved that the electromagnetic interference exists in the secondary devices of Suidong convertor station and the improvement measures are suggested by the simulation and experimental results.