A Comprehensive Approach for Transient Performance of Grounding System in the Time Domain

It is important to identify the impulse performance of the grounding system for lightning protection. However, the performance is nonlinear and dynamic under impulse condition. The electrical parameters of the grounding system are not only frequency dependent, but are also time dependent. Moreover, the mutual couplings between the grounding conductors cannot be ignored. Based on the hybrid electromagnetic method and vector fitting, a time-domain approach for the transient performance of the grounding system is developed. All the aforementioned phenomena can be covered in this method. Meanwhile, the sudden change of the parameters resulting from the soil ionization is also successfully dealt with in this paper. Compared with previous study results and field tests, the method proves to be reliable and effective.

I. Introduction

The impulse performance of the grounding system plays an important role in lightning protection. The grounding system is required to have “sufficiently low impedance and current-carrying capacity to prevent the buildup of voltages that may result in undue hazard to connected equipment and to persons” [1]. For evaluating the protection effect of the grounding system, it is essential to analyze its characteristics.