故障电流多点入地接地网接地阻抗数值分析

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 %。

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

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.