Finite element dynamic model of ocean grounding electrode characteristics based on circuit and electric–thermal field coupling

Considering the unique soil structure and the temperature rise effect of seawater’s electrical and thermal parameters, accurately simulating the grounding characteristics of marine DC grounding electrodes is the basis for ensuring the safe and stable operation of offshore wind power grid-connected DC projects. The paper proposes a dynamic finite element model of ocean grounding electrode characteristics based on the coupling of circuits and electrical–thermal fields. In the finite element model, soil parameters can be controlled by the time-varying temperature distribution, and the dynamic process of the coupling of soil electrical and thermal fields in the process of direct flow can be accurately simulated. A time-varying equivalent circuit model for controlling the electric–thermal field can be implemented to accurately simulate the dynamic process of the shunt coefficient for each conductor segment in a composite DC grounding electrode with multiple injection points. The effectiveness is verified by comparing with the experimental data. Finally, the dynamic flow process, temperature rise process and their mutual influence are quantitatively analyzed.