A.C.-d.c. load flows with realistic representation of the convertor plant

H.V. d.c. convertor stations contain a.c. plant components which are specified by their relationship with d.c. link parameters and cannot be represented in conventional terms within the a.c. load-flow solutions. In the paper a comprehensive d.c. link model is developed with generality to represent all the plant components and operating conditions encountered in practice. The New Zealand a.c.-d.c.-a.c. scheme is used as a test system, and the results show that a unified fast-decoupled load-flow solution of two and three a.c. systems interconnected by the d.c. link converges for all practical operating conditions without increasing the number of iterations.