基于瞬时负序分量的小电流接地选线

Fault Line Selection for Small Current Based on Instantaneous Negative-sequence Component

针对配电网单相故障下负序电流分量受接地过渡电阻影响小且与中性点接地方式无关的特点,提出一种负序分量提取法,即瞬时分量法。相较于积分法和微分法,瞬时分量法可以在时域内提取系统负序电流的实时曲线。通过比较故障前后负序时域电流对应时间点的差值,可以降低不平衡电流的影响,且此差值的暂态分量及稳态分量可作为选线标准。仿真及动模实验均验证了该方法的有效性。

In allusion to characteristics of negative-sequence current component being affected lightly by grounding fault re- sistance and irrelevant to neutral point grounding mode in the condition of single-phase fault of power distribution network, this paper presents a kind of negative-sequence component extraction method called instantaneous component method. Com- pared with merits and demerits of integral method and differential method, instantaneous component method can extract re- al-time curve of negative-sequence current in time-domain. By comparing difference value of time points of negative-se- quence domein current before and after the fault, it is able to reduce influence of unbalance current and the transient compo- nent as well as steady-state component of this difference value can be taken as line selection standard. Dynamic simulation experiments verify effectiveness of this method.