以降低跨步电压为目标的直流多环接地极电流配比的优化

为有效降低高压直流接地极的跨步电压,减小其设计尺寸和建设成本,以直流双环接地极为例,提出了一种采用强制均流电阻降低多环接地极跨步电压最大值的方法。基于电磁场理论以及对水平多环结构接地极地表跨步电压分布特性的分析,研究了双环接地极电流配比与跨步电压峰值之间的变化关系,寻求各环电流的最优配比,使整体跨步电压最大值降到最低。最后,通过实验验证了该方法的应用效果。分析和实验结果表明,通过均流电阻调节电流配比,能够有效降低接地极的跨步电压,且对接地极本身性能的影响较小,具有工程实用价值。

Decreasing Step Voltage by Optimizing Current Distribution Proportion of Multi-ring DC Ground Electrode

By decreasing the step voltage,the size and cost of DC ground electrode could be significantly reduced.Focusing on double-ring DC ground electrode,we proposed a new method to decrease the maximum step voltage by employing grading resistances.Based on the electromagnetic field theory and the analysis of the step voltage distribution characteristics of multi-ring ground electrode,the relationship between the maximum step voltage and the current distribution proportion among ring electrodes is established,which could be used to optimize the value of grading resistance and to minimize the maximum step voltage.Meanwhile,the method is validated by experiment in laboratory.The results of both theoretical analysis and experiment show that adjusting current distribution proportion between two ring electrodes using grading resistances can decrease the step voltage effectively,and little affects the ground electrode.This method can be put into actual application.