带同杆双回线的T型线路故障分支判定算法

针对T型线路中出现同杆双回线的线路结构,提出了判定故障分支的新方法.该方法以六序分量法为基础,当某支路发生故障时,首先求取各支路保护安装处的突变电气量,然后通过正序网络图,计算2个必要的参数用于判别故障支路,区分非同杆双回线故障、同杆双回线的跨线故障,以及同杆双回线的单回线故障.该方法的特点是考虑了同杆双回线的跨线故障,能够确定同杆双回线中的单回线的故障回路以及跨线故障,并且物理意义明确.序电流可以用来区分同杆双回线的同名相跨线故障.同时,进行了大量的EMTP仿真,结果表明支路判断的准确度不受系统运行方式、故障点过渡电阻等因素的影响,并且也能很好地适用于不对称同杆双回线路.

Faulted Line Selecting Method of T Circuit of Parallel Transmission Lines

Based on the analysis of fault feature of teed circuit of parallel transmission lines, a new fault line selecting method is proposed. When fault occurs, the positive sequence fault components at the bus where the protection relay is installed are used to calculate the mutation voltage and mutation current in order to obtain the related voltages at T node. The ratio of the related differential voltage can be used to identify the faulted line. This method can be used to specify the cross-phase fault and single line fault of the parallel line as well as cross-pole fault. The faulted line can be identified correctly by using the new method. The result of EMTP simulation indicates that this method is not affected by fault resistance and system operating mode. It can also be applied in asymmetrical parallel transmission lines.