The rated current of ±800kV Ultra High Voltage Direct Current (UHVDC) Transmission system can be up to 6250A, so that the influence of the DC grounding current of electrode is enormous. It is of great significance to understand the distribution characteristics of DC earth potential near the grounding electrodes and the influence of the grounding current to propose prevention and controlling schemes. According to the needs of Shanghaimiao-to-Shandong UHVDC terminal grounding electrode DC bias treatment project, a three-dimensional (3D) earth resistance model of 310km depth is established by the data of shallow earth resistance measurement and deep magnetotelluric data of 1°×1°longitude and latitude measurement point. The distribution of earth surface potential in the total area of 204.3 thousand square kilometers under 6250A DC is calculated by the finite element method. The results show that the larger the current entering the grounding electrode, the larger the influence range. Additionally, the distribution of equipotential lines were relatively dense in the area 80 kilometers away from coastline under the influence of coast effect and sparse in the area with high earth resistance.

The IGBT device in the converter valve device will produce complex electromagnetic disturbance signals in the process of fast on and off, and the driving circuit is close to the device. In this paper, the wireless energy transmission system based on magnetic coupling resonance is used to replace the traditional driving power supply method, which makes the electromagnetic environment in the space where the driving circuit is located more complex. In this paper, firstly, the test is completed according to the relevant standards of the drive circuit, and then the electromagnetic simulation software is used to complete the modeling and simulation of the converter valve based on the wireless energy delivery system, which proves that the drive circuit can withstand the electromagnetic disturbance generated by the wireless energy delivery system and the converter valve, and there is no need to add additional shielding measures.