高压直流输电线路故障行波传播特性及其对行波保护的影响

摘要

The lossless transmission line model is widely used in research of propagation characteristic of fault traveling wave on HVDC line, but traveling wave dispersion is not considered in the model. And the influence of DC line terminal devices is not considered in research of traveling wave protection (TWP). The causation, the characteristic and the influencing factors of fault traveling wave dispersion are analyzed in detail. Influence of DC line terminal devices on the reflection of different frequency component of fault traveling wave is also analyzed. And then, influence of the forenamed two factors on TWP is studied. It is shown that dispersion mainly affects the earth mode component of fault traveling wave. Both the forenamed two factors also have effect on the amplitude of fault traveling wave, which affects the criterion of voltage change of TWP;the fault traveling wave gradient, which affects the criterion of voltage change rate of TWP, is affected limitedly by dispersion. And it can be confirmed by the aerial mode component of fault traveling wave.%高压直流输电线路故障行波传播特性研究多采用无损传输线模型作为研究对象而未考虑行波色散的影响；直流线路行波保护研究通常未考虑线路末端设备的影响。分析了故障行波沿直流线路传播产生色散的原因、特点以及影响因素；分析了直流线路末端设备对故障行波中不同频率分量的影响。在此基础上研究了行波色散及末端设备对行波保护的影响。研究表明：故障行波的色散主要体现在其地模分量上。故障行波波头幅值的变化影响行波保护的电压变化量判据，受前述两因素的共同作用；故障行波波头陡度的变化影响电压变化率判据，受行波色散影响有限，主要由故障行波的线模分量确定。