Development Of Compact Filters For Hvdc Converter Station

500 kV large-capacity HVDC transmission is expected in near future in Japan, for which development of reliable, compact and economical equipment is important. As a first step toward this objective, a prototype compact 154-kV 9-Mvar AC double-tuned filter and a prototype compact 125-kV DC filter were developed, which are first kind in the world and are currently under long-term life test. Each filter consists of a capacitor unit and a reactor unit, both dead tank design for ground-level installation. Film-paper mixed dielectric is used for capacitor elements, and polycyclic aromatic hydrocarbon oil as impregnant and for insulation.