基于电压序量变化量的超高压混合线路故障测距方法

A Fault Location Method for Extra-High Voltage Mixed Lines Based on Variation of Sequence Voltage

超高压混合输电线路电缆区段及架空线区段线路参数不同,因此均匀线路测距方法无法使用。针对混合线路参数特征,提出了基于电压序量变化量的超高压混合线路故障测距方法。首先研究了混合线路沿线电压序量的快速计算方法。然后针对超高压架空线?电缆混合线路中的不对称故障,提出采用沿线负序电压幅值比较的故障位置定位方法;针对其对称故障,提出采用沿线正序电压变化量幅值比较的故障位置定位方法。EMTDC仿真表明所提算法计算速度快、测距精度高,不要求双端电气量同步,不受过渡电阻影响,且不存在伪根识别问题。

For mixed EHV lines, parameters of cable and overhead line segments are different, so fault location method for uniform line cannot be used. Based on characteristics of mixed lines parameters, a fault location method for mixed EHV lines based on variation of sequence voltage is proposed. First, precise fast calculation method of voltage along line is investigated. Then, for asymmetric fault, fault location method of comparing negative sequence voltage amplitudes along mixed lines is proposed. For three-phase symmetry fault, fault location method of comparing amplitude variations of positive sequence voltage is put forward. Finally, simulation is carried out using EMTDC. The proposed algorithm is computationally efficient with high precision. It does not require synchronism of two-terminal electric parameters, is not affected by transition resistance, and eliminates false identification problem.