Electromechanical filter and its performance in d.c. transmission systems

It is shown that a novel filter based on an electromechanical principle is superior to conventional static filters with respect to both suppression of harmonics and supply of reactive power to convertors. New forms of filter are proposed based on the same electromechanical principle, and the design philosophy is briefly discussed. A steady-state stability analysis of a d.c. link between weak a.c. systems reveals that the stable regime is wider with the new filter than with the conventional static filters.