## 1 Introduction  
With the rapid development of modern science and technology, the co-existence of sophisticated megawatt electric power converters, together with highly sensitive electronic equipment, has become increasingly widespread. The high-density and wide-spectrum electromagnetic emissions generated by the power electronics equipment operation fill the entire space, forming a complex electromagnetic environment. That intensive electromagnetic field inevitably affects the other electronic equipment and systems. The complex electromagnetic environment requires electronic equipment and power supplies to have robust and ultimate electromagnetic compatibility. For any electronic equipment working in an electromagnetically polluted environment, the suppression of electromagnetic interference has become nowadays, a necessary accompanying technology. The converter station is the most important part of the UHV DC project, in addition to the transmission line part. Through the converter station, the direct current and the alternating current sides of the power system, are bidirectionally converted to satisfy the power system's requirements for safety, stability and power quality. The main structure of the converter station includes a valve hall, a converter transformer, AC switchyard, smoothing reactor, filter, reactive power compensation equipment, etc. The high-voltage converter valve is subjected to high electrical stress, large energy transients, and high electromagnetic noise intensity. The stronger and weaker electronic devices are in close vicinity and the mutual coupling of the system is tight. Hence, the electromagnetic interference by coupling mechanisms inside the high-voltage power converter valve is complex. To ensure the quality of service and the safety of the electrical transmission, the inspection of the power lines and the work areas in its vicinity, has always been the core work of the power system management. In recent years, with the deepening integration of artificial intelligence into the power system industry, unmanned equipment (UAVs), unmanned vehicles, and inspection robots have been widely used in this application field, thereby reducing operating costs and improving operating efficiency. The equipment inspection robot system uses autonomous or remote-control devices, to inspect the outdoor high-voltage equipment outside of the unattended or less-attended converter stations. The robotic equipment can detect defects in the power equipment, inside and outside of the power station. It can detect undesirable objects hanging and other abnormal phenomena in time. The inspection robot will automatically alarm or troubleshoot the situation, according to the set rules. With their capacity of being independent of the terrain, UAVs have unparalleled advantages in the operation of power equipment in remotely inspected locations. Whether it is communication between UAVs or direct communication between UAVs and ground transmission stations, they all rely heavily on the mobile wireless network between them. Due to the influence of the multipath fading and Doppler frequency shift in the mobile communication system itself, the wireless channel is extremely variable, which will have a strong negative effect for any modulation technology [1]. In addition, the electromagnetic pulses from the power converter equipment will also affect harmfully the electronic components of the UAVs. When drones are used in converter station inspections, the strong electromagnetic fields generated by the transmission lines and equipment will strongly interfere with the communication and control systems of the drones that are flying close to the emission. In severe cases, they will cause the flight control to fail and the drone to crash, and even endanger the power lines.