不并列运行的同杆双回输电线路跨线故障计算

针对不并列运行的同杆双回输电线路的跨线故障,提出了基于正、负、零三序分量法结合故障边界条件及复合序网图进行分析的解析法。通过相序变换可知该型线路只有零序网络之间存在耦合,利用线路三序分量的特点结合疏松耦合变压器模型建立系统各序网络的等值电路;为简明直接地分析跨线故障,分析总结了典型简单故障形式的边界条件和复合序网图的连接方式,可以方便地组合成各种跨线故障的边界条件和复合序网图,避免对不同跨线故障的重复分析。该方法物理意义明确,计算简单,适用于两回线路参数不同的情况,也适用于非全程同杆双回输电线路的跨线故障。PSCAD/EMTDC仿真验证了该方法的正确性。

Inter-line Fault Calculation for Double-circuit Lines Under Non-parallel Operation

To analyze and calculate the inter-line fault on double-circuit lines under non-parallel operation, an analytical method based on three sequence component method combined with fault boundary conditions and the graph of compound sequence networks is proposed. According to phase-sequence transformation, it is known that coupling exists only between zero-sequence networks for this type of lines. Then an equivalent circuit of each sequence network is developed based on the three sequence component characteristics while referring to a loosely coupled transformer model. For concise analysis of the inter-line fault, the boundary conditions and the way the graph of compound sequence networks is connected for sample and typical failure modes are summarized, which can be combined into boundary conditions and interconnection of sequence networks for a variety of inter-line faults. Thus repeated analysis of different inter-line faults is avoided. The method has a definite physical meaning and is simple in calculation and can be used to analyze inter-line faults of different parameters of two lines and incomplete-journey double-circuit lines. It is proved by simulation of PSCAD/EMTDC.