The interference on geoelectric resistivity observation of seismic station from UHVDC power lines becomes increasingly prominent with growth of UHVDC transmission projects. According to the interference mechanism of DC transmission lines on geoelectric resistivity observation

the authors have established a 3-D combined-layer soil model to calculate the potential distribution of grounding current in soil. An equation for the potential distribution at any position is deduced by using the model and equivalent complex image method. Geoelectric resistivity observation experiments are conducted at both observatories and field observation points during the live debugging of ±800 kV Jinping-Sunan UHVDC power line. Further analysis indicates that the obtained results by using the proposed model and equations are in good accordance with the experimental results

and the error is less than 10.28%

while the distance between DC power line and geoelectric resistivity observation of seismic station is no more than 10 km.