故障电流多点入地接地网接地阻抗数值分析

Numerical Analysis of Grounding Impedance for Grounding Grids with Multi-Points Short Circuit Current into the Ground

降低变电站接地网的接地阻抗是保证人身和设备安全的重要措施。基于矩量法和场路结合的思想 ,提出了一种新的接地网工频接地参数计算方法。该方法既考虑了接地导体的电阻和自感 ,又考虑了导体间的互感 ,并可计算故障电流多点入地的大型变电站接地网工频接地参数。计算结果表明 ,对于大型钢材接地网 ,电气设备采用 4条接地引线并接在地网不同位置时 ,接地阻抗降低量 >10 %。

It is an important measure to reduce the substation grounding impedance for the safety of people and facilities. Based on method of moment and field-circuit coupling theory, a numerical calculation method of substation grounding grids is presented. The resistance and self-inductance of conductors as well as mutual inductance between conductors are taken into account. The grounding parameters with multi-points short circuit current into the ground can be calculated in industry frequency condition. The results show that the grounding impedance can be reduced more than 10% by the facility connected in different locations of a large steel grounding grid with 4-leading wires.