*Article* **A New Approach to Include Complex Grounding System in Lightning Transient Studies and EMI Evaluations †**

#### **Vegard Steinsland** *∗***, Lasse Hugo Sivertsen, Emil Cimpan and Shujun Zhang**

Department of Electrical Engineering, Western Norway University of Applied Sciences, 5063 Bergen, Norway


Received: 7 May 2019 ; Accepted: 12 August 2019; Published: 15 August 2019

**Abstract:** A new approach to lightning transient studies including complex grounding grids is presented in this paper. The grounding system is modeled in Matlab/Simulink based on the transmission line theory. Using a bottom-up approach and considering the properties of the fundamental elements, a detailed view of measurement values will be presented and analyzed. The Matlab/Simulink grounding system models are interfaced for co-simulation with EMTP-RV trough Functional Mock-up Interface (FMI) 2.0. This modeling approach allows the use of the full component library and network design by EMTP-RV to evaluate and analyze the effects of the grounding system and transmission network simultaneously in Matlab/Simulink. The results present a simplified transmission system where a surge is injected, Conseil International des Grands Réseaux Électriques (CIGRE) 1 kA 1.2/50, in far-end of a transmission line. When reaching a substation, the surge is injected into the grounding system through a surge arrester.

**Keywords:** grounding system; substation; lightning; transmission system; surge arrester performance
