Utilizing neutral GRC modeling based on resistive network for detecting geo-electrical structures and analyzing its impact on HVDC power grids

Abstract

Ground return currents (GRCs) induced by monopole power grids provide insights into subsurface geoelectrical structures. However, accurately modeling GRCs is challenging due to ultralong-distance power lines with resistivity contrasts between conductors and the ground. To address this, we propose a novel calculation method using a node voltage (NV) resistance network (RN) approach, leveraging an expandable octree grid inspired by Kirchhoff’s RN (KRN). The NV method ensures conservation of current and voltage equations, preserving complete geoelectric information. By integrating a symmetric system and adaptive octree grid, the method achieves higher accuracy and computational efficiency. Numerical examples show accuracy improvement from 1 % to 0.1 %, a reduction of computation time by 80 %, and 78 % fewer elements. Validation through a bedrock investigation demonstrates inversion results consistent with independent surveys, confirming the method’s applicability.