【摘要】 220kV及以上的架空地线，多采用分段绝缘方式运行，其地线绝缘子并联间隙在系统接地故障期间会击穿放电。间隙击穿放电后线路电磁耦合关系的骤变，会引起相应线路零序阻抗Z0的大幅变化。本文从定性和定量的两方面分析了这种变化，并将计算值、设计值和现场实测值交互对照，提出Z0的上述变化一定条件下会引起线路保护的误动或拒动。更多还原

【Abstract】 It is our usual practice in China for the O/H groundwires of 220kV & above transntission lines to be sectionalized yet insulated via special insulator to which a shunt protective gap is attached.This gap will spark over & disrupt when the lines subject to phase-to-earth faults.There leads up to the sudden decrease of zero -sequence impedance Z0.Due to the change ofelectrostatic & electro magnetic coupllngs between phase lines and groundwires.This paper analyses this phenomenon from both qualltative and quantitative sides,and presents the mutual Comparison among the calculated,the designed and field-tested values.Furthermore,the paper points out that relevant power relaying may be subject to mal-fonctioning under certain conditions in connection with the aforesaid sudden change ΔZ0.更多还原