Multi-Infeed HVDC Interaction Studies Using Small-Signal Stability Assessment

This paper presents an analysis of multi infeed high-voltage dc (HVDC) interactions using small-signal analysis techniques. The modeling details that are necessary to adequately represent the dynamics of the HVDC converters and the ac network are investigated, and the models are validated against an Electromagnetic Transient Simulation program. The paper shows that ac network dynamics must be modeled in order to obtain meaningful results from the small-signal stability study. A small test system with two HVDC infeeds is then used to demonstrate the presence of interactions in that system. The case studies presented in this paper indicate that it is possible to have interactions between the HVDC terminals in an ac system. This paper recommends that a small-signal interaction study, which is similar to what is presented in this paper, should be performed to identify these interactions.