Continuous p-v-Characteristic Parameterization for Multi-Terminal HVDC Systems

Abstract

Existing local dc node voltage control characteristics for HVDC grids are dedicated to special control modes of converters with a limited variability/flexibility. Thus, also an adaptation of those characteristics according to special grid requirements is highly restricted. This paper proposes a new characteristic which is an explicit and thus continuous function covering the entire allowed operation area of a converter. This new formulation allows us to emulate all existing characteristics but also to continuously adapt the control characteristics shape towards (changing) grid requirements. A method to parameterize this characteristic according to the degree of availability of dc balancing power from the ac grid by close by units is described as well as parameterization rules to emulate existing characteristics.