故障相的故障分量综合阻抗特点分析

Characteristics analysis of integrated impedance of fault components

使用三相模型,推导了故障分量综合阻抗与序分量综合阻抗之间的关系,指出故障相的故障分量综合阻抗在数值上与故障时的故障分量正序综合阻抗接近。同时它还具有小于两侧系统阻抗中比较大的、大于比较小的系统阻抗的特点,且在应用于弱馈系统时,故障分量综合阻抗小于线路阻抗与较小的系统阻抗的2倍之和。使用EMTP建立了500 kV,400 km线路模型对分析结论进行了验证。该结论可用于故障分量综合阻抗纵联保护原理的整定计算及定值灵敏度的分析。

A three-phase model was used in the paper,and the relationship between sequence integrated impedance and fault component integrated impedance of fault phases was discussed.The analysis results show that the fault component integrated impedance of faulty phases is very close to the positive sequence fault component integrated impedance of faulty phases.Otherwise,integrated impedance of fault components also have characteristics that they are less than the larger system impedance among impedance of two sides of the system and it is greater than the lower system impedance among impedance of two sides of the system.When applied in week feedback systems,the integrated impedance of fault components are less than the sum of line impedance and double system impedance of the lower one.A 500kV,400 km line model is established by EMTP in proving analysis results.The results can be used in setting calculations of pilot protections based on integrated impedance of fault components and the analysis of sensitivities.