特高压直流同塔双回输电线路互感对电压突变量保护动作特性的影响

Influence of Mutual Inductance between HVDC Double- circuit Lines on Same Tower on Operating Characteristics of Voltage Fault Component Protection

针对宾金特高压直流2014年7月31日不对称运行时所出现的极1故障导致极2闭锁事件进行了细致的分析。分析结果表明,由于特高压直流线路采用同塔双回方式架设,线路间互感作用明显,在暂态过程中一极电流突变会在另一极中产生明显的感应电压,导致直流电流失控。对特高压直流同塔双回输电线路互感作用的机理进行了分析,并探讨了互感在暂态过程中对电压突变量保护的影响。最后根据试验结果对电压突变量保护的定制修改提出了建议。

During the asymmetric operation of HVDC transmission project from Yibin to Jinhua on 31 st July 2014, its first pole ran up against a fault condition, which resulted in the blocking of the second pole, so a detailed analysis is carried out. As the two circuits of HVDC transmission lines share the same tower, there exists an obvious mutual inductance between the lines. So the sudden change of the current in one pole under transient process will give rise to an evident induced voltage in the other pole, which will lead to the direct current out of control. The mutual inductance action mechanism of HVDC double - circuit lines on the same tower is analyzed and the influence of the mutual inductance on the voltage fault component protection is dis- cussed. Finally, the advices for modifying the setting values of the voltage fault component protection are given based on ex- perimental results.