基于EMTP的地网暂态计算模型

EMTP-based Model for Transient Calculation of the Grounding System

作为变电站电磁环境评估的重要内容 ,提出了考虑导体间互导纳及土壤电容效应的地网暂态计算不等电位模型和相应的基于EMTP的计算方法 ,使计算速度提高。不同地网仿真计算及与CDEGS比较的结果显示 ,对于工频短路或雷击变电站的情况 ,该模型满足工程要求。该方法应用于变电站地网模拟计算中 ,可快速准确地进行地网设计工作 。

The simulation of the transient characteristics of the grounding system in substation is an important task in EMC researches. In this paper, the author proposes a grounding transient model. In this model both circuit approach and field approach are used and it is finally converted into a no-coupling impedance network. The mutual admittance between conductors and the capacitance effect of the earth have been considered in this model, and a special computing method based on EMTP is established according to its characteristic to make computation faster. The author has done some simulations to different grounding systems and compared with MOM. IT shows that high degree of approximation. This proves that it satisfies required precision of engineering calculations under power frequency short circuit or lightning stroke. And for its fast computing speed, this method is suitable for engineering calculation of transient characteristic of general grounding systems.