Electromagnetic Interference Prediction of ±800 kV UHVDC Converter Station

Electromagnetic interference (EMI) is mainly caused by the periodic valve switching in HVdc converter stations. This EMI can result in high-frequency conducted and radiative interference toward the adjacent communication, computer equipment, carrier system, and radio stations. Therefore, a wideband model of a converter system is necessary to predict the characteristics of the EMI source. Methods of modeling are proposed, and the equivalent circuits of the main equipment in ultra-HVdc (UHVDC), including valve section, converter transformer, smoothing reactor, filters, and so on, are developed in this paper. The whole wideband model is simulated by PSCAD/EMTDC. Based on this model, the characteristics of the conducted EMI under normal operation conditions are calculated. Ground-level electric field strength and magnetic field strength in and around a UHVDC converter station are calculated. For validity, a comparison between the simulated and the measured data is conducted.