输电线路的潮流介数及其在关键线路识别中的应用

摘要

根据输电线路在电网发电负荷节点对间的功率传输中被利用的程度，同时考虑发电容量和负荷水平的影响，提出输电线路的潮流介数指标，并以此作为辨识关键输电线路的判据。该判据能够适应电网不同运行方式下潮流分布的特点，量化了输电线路在全网功率传输中的作用和贡献，其物理背景更加符合电力系统实际。甘肃电网的实际算例表明，电网中输电线路的潮流介数具有显著的异质性特点，少数的几条输电线路在电网的功率交换中起到关键作用；基于潮流介数的相继故障方式下的负荷损失明显高于已有电气介数指标和随机故障方式；以潮流介数指标识别出的关键输电线路以及电网不同运行方式对潮流介数的影响结果，非常符合甘肃电网的实际运行特点；从而证明了利用潮流介数辨识关键输电线路的有效性。%A new concept of flow betweenness of power transmission line is proposed as a criterion for critical line identification in a power system.This new concept is based on comprehensive consideration of the extent of a transmission line used by different generator-load pairs,and the influence of generating capacity and load level.The criterion can adapt to the variation of power flow distribution under different operation modes.It can also quantify the contribution and effects of transmission line on the whole grid power transfer with a more comprehensible physical background.Case studies based on Gansu power grid show that the flow betweenness distribution of transmission lines has typical heterogeneous characteristics,i.e.a small number of transmission lines play critical role in the power exchange,and the load loss under cascading failure based on flow betweenness is significantly higher than the existed electrical betweenness and random cascading failure manner.Moreover,the critical line identification results and the influence of different operation modes on flow betweenness are closely in line with the actual operation characteristics of Gansu power grid.The case study results clearly validated the effectiveness of flow betweenness.