Influence of UHVDC System on the Security and Stability of AC/DC Interconnected Power Grid

With CSG as an example,the interaction mechanism between AC and DC systems in a AC/DC interconnected power grid is discussed with PSS/E software to open out the possibility of the grid being in instability.Analysis shows that receiving-end AC fault damages the HVDC system operation much more than the sending-end AC fault in a multi-infeed HVDC system,and its damage extent depends on the power recovering rate of the HVDC system,and for a HVDC system with slow power recovering rate,the receiving-end AC fault will possibly become a critical one to restrict transmission capacities.The larger is the capacity of the HVDC system,the higher is the transmission capacities of the parellel grid,but more expensive cost of system stability control.