Small-Signal Stability Analysis of the Interactions Between Voltage Source Converters and DC Current Flow Controllers

Small-signal stability analysis of the voltage source converter (VSC) based multi-terminal DC (MTDC) grids has been mainly focused on the dynamics of AC/DC converters while there is a lack of consideration of DC networks with DC power-flow controllers. In this paper, an integrated small-signal model is established to investigate the interactions between VSC and DC current flow controllers (CFC). The impacts of the control system of CFC on small-signal stability of the integrated system and the impacts of the control system of VSC on the DC networks with CFC are discussed via eigenvalue analysis. The above interactions are demonstrated through dynamic simulations against both small and large disturbances using real time digital simulator (RTDS).