Behaviour of h.v. d.c. links under balanced-a.c.-fault conditions

A dynamic model is described which contains the main elements influencing the behaviour of an a.c./d.c. link during the first few cycles after a disturbance. Particular importance is given to the representation of the a.c. system, convertor filters and automatic controls. A digital-computer program based on this model is used to investigate the behaviour of the convertors under 3-phase short-circuit fault conditions, with strong and weak a.c. systems. The program is also used to investigate the influence of conventional and equal-firing types of control on the convertor behaviour.