Measurement and Analysis of Radiated Disturbance Characteristics of ±320 kV Modular Multilevel Converter System

The radiated electromagnetic disturbance was evaluated by measuring the electric field intensity in a bandwidth of 10 kHz-2.75 GHz near the valve hall, direct-current (DC) area, reactor room, and transformers in a ±320-kV modular multilevel converter-based high-voltage, direct-current (MMC-HVDC) converter station. In addition, the distribution of electric field intensity was analyzed in various regions in the converter station. According to the law of electric fields attenuation with distance, the radiated electric field intensities at the position 200 m away from the converter station was calculated by using the electric fields measured in the converter station. The results show that the levels of radiated disturbance inside and outside the converter station meet the standards' requirements. The amplitude spectra of the electric field intensity in a traditional HVDC system and MMC-HVDC system were compared. Finally, the mechanism for radiated electromagnetic interference of the MMC-HVDC converter system was analyzed from the aspects of disturbance source characteristics, wall shielding and radiated structure.