基于频域电网络模型接地体冲击散流分布的研究

Research of the Impulse Current Dispersal of Grounding Grid Based on Electrical Network Model in Frequency-Domain

研究接地体冲击散流特性是优化地网冲击特性、降低输电线路雷击跳闸率的重要措施。通过对接地导体分段建立频域电网络模型模拟接地体冲击泄流过程,采用迭代法考虑土壤动态电离对散流分布的影响,并利用CDEGS软件仿真及真型散流试验对频率电网络模型及其迭代求解结果进行了对比验证。本文研究了标准电流波形下水平伸长接地体在不同接地体尺寸、不同土壤电阻率及不同电流峰值下的散流规律,得出接地体冲击散流不均匀分布是由导体段之间对地互阻抗及电感效应引起的。

The research of impulse current dispersal regularity of grounding grid is an significance measure to optimize impulse characteristics of grounding network and reduce transmission line lightning-trip rate. The iterative method is used to analyze effect of soil ionization on leak current distribution by establishing a frequency-domain electrical network model based on grounding conductor segmented to simulate discharge process. The suggested model and the iteration results are compared and validated by CDEGS software simulation and full-scale current dispersal tests. The impulse current dispersal regularity of horizontal elongation grounding device under the standard current waveform in the conditions of different length of grounding electrodes, different soil resistivity and current amplitude. Finally, it is concluded that the uneven distribution of impulse current dispersal is caused by the mutual impedance of conductor segments and the inductance effect.