考虑土壤电阻率的特高压直流输电线路过电压抑制措施

特高压直流输电(ultra high voltage direct current transmission, UHVDC)以输电容量大、线损少、输送距离远等显著优势成为解决中国能源与需求呈逆向分布问题的重要方案。然而，由于其输送距离远，跨越区域的地形和气候复杂，使线路沿线土壤电阻率分布不均匀。基于准东—皖南±1 100 kV特高压直流输电工程，分析了直流线路过电压机理，并采用电磁暂态计算软件PSCAD,针对直流线路不同平均土壤电阻率和四季实际土壤电阻率进行过电压仿真分析。结果表明，土壤电阻率会对换流站的反射产生影响，以及实际土壤电阻率会使最大过电压位置向送电侧偏移。通过优化线路避雷器的安装位置使过电压的抑制效果更优，为特高压直流输电工程的发展提供重要参考。

Study on the Influence of Soil Resistivity on Overvoltage of UHVDC Transmission Line and Its Suppression Measures

In order to solve the reverse distribution of energy and demand in China, Ultra high voltage direct current transmission (UHVDC), which has significant advantages such as large transmission capacity, low line loss and long transmission distance, has become an important scheme. However, due to its long transmission distance, complex terrain and climate across the region, the distribution of soil resistivity along the line is uneven. Based on a ± 1100 kV UHVDC transmission project, the overvoltage mechanism of DC line is analyzed in this paper. The electromagnetic transient calculation software PSCAD is used to simulate and analyze the overvoltage of DC line with different average soil resistivity and actual soil resistivity in four seasons. The results show that the soil resistivity will affect the reflection of the converter station, and the actual soil resistivity will make the maximum overvoltage position shift towards the transmitting side. It is concluded that the overvoltage suppression effect is better by optimizing the installation position of line arrester, which provides an important reference for the development of UHVDC transmission project.