Least squares exponential fitting of surface potential

The rated currents of the ground electrodes of the 800kV, 8000MW and 10000MW converter stations built in my country in recent years are 5000A and 6250A respectively. Due to the large ground current flowing into the DC ground pole, on the one hand, the ground potential (ESP for short) has a greater impact on the underground pipeline network; on the other hand, the ground potential (ESP for short) has a greater impact on the underground pipeline network. On the other hand., the distribution of DC near-earth potential is more complex due to the larger influence range and the differences in the electrical characteristics and structure of the earth. When the high-voltage DC ground electrode is operating., the ground surface potential increases., generating a DC bias voltage. DC bias can cause serious harm to the safe operation of power systems. The fundamental reason for the harm caused by DC bias lies in the uneven distribution of surface potential. To address this issue., this paper explores the mathematical method for finding multi-layer soil potentials and how different soil structure models use least squares exponential fitting to recover surface potentials.