Measurement and Analysis of Shielding Effectiveness of the Valve Hall of VSC-HVDC Converter Station

Converter valves of VSC-HVDC can produce up to tens of MHz of electromagnetic radiation during operation, which may disturb the normal operation of sensitive equipment, or exceed electromagnetic environment standard limit. Therefore, electromagnetic shielding measures are usually indispensable. Typically, shielding is implemented by covering the valve hall wall with metallic sheets or inserting metallic mesh into the wall. In this paper, we report the measured results for the shielding effectiveness of two converter stations with mesh shielding and sheet shielding, respectively. We selected 30 and 18 observation points for the mesh and sheet shielding, respectively. For each observation point, two kinds of antenna polarization mode, vertical and horizontal, are considered. The test results show that the shielding effectiveness of metal mesh is about 10-30 dB, whereas the metal sheet can reach about 30-70 dB.