Analysis of Voltage and Power Interactions in Multi-Infeed HVDC Systems

In recent CIGRE literature, an index was proposed to assess the degree of voltage interaction among HVDC converters in a multi-infeed configuration. However, the index is derived from empirical information, its usage is somewhat arbitrary or "rule-of-thumb" basis. In this paper, a power-flow model is used as the mathematical framework to derive an analytic equivalent of the empirical index, to facilitate rigorous analysis of voltage/power interactions in multi-infeed HVDC systems. Moreover, with other allied new indices proposed here and in past works, it is shown that a taxanomy of indices can be established with their interrelationships derived analytically. Furthermore, it is shown that these analytic indices can give theoretical insight into the parametric dependence of the power/voltage interactions.