Impact of Load Models to DC Recovery Performance in Multi-feed HVDC Grid Including UHVDC

Load models have a great impact on power system transient stability especially on voltage stability, it is extremely necessary to study the influence of load models on the post-fault HVDC dynamic recovery performance. The influences of both ZIP and IM model with different composition proportion on post-fault multi-HVDC recovery performance are studied, as well as the impact from IM protection characteristic of lower-voltage-cut-restart.The HVDC recovery performances between the recommended typical CSPG IM type and the IEEE6 IM type are compared.The multi-infeed interaction factor (MIIF) is introduced to analyze the interaction of dynamic recovery performance among the HVDC inverter stations under fault. Results reveal that influence of load model in sending-grid on DC recovery performance is completely opposite to the influence of load model in receiving-grid, and to a certain voltage drop extent, the recommended typical CSPG IM load in sending-grid is better at enhancing transient angle stability and the IEEE6 IM load is better at enhancing transient voltage stability, no matter in sending or receiving grid.