Influence of load model on UHVDC Emergency DC Power Support strategy

The mechanism of UHVDC Emergency DC Power Support (EDCPS) to enhance transient stability of multi- machine system is analyzed briefly based on EEAC (Extended Equal Area Criteria), and the influence of load model characteristic including ZIP static load model and IM (Induction Motor) model on UHVDC EDCPS effect after heavy disturbance is further studied, and the corresponding UHVDC EDCPS Strategies should be modified with different load models to keep system stable. Studies reveal that the influence of sending-grid ZIP characteristic on post-fault EDCPS effect is completely opposite to that of receiving-grid. Under heavy disturbance IM load absorbs more active power than that of ZIP load and the influence of sending-grid IM load on post-fault EDCPS angel stability is completely opposite to that of receiving-grid. As for the influence on EDCPS effect between synthesis load and ZIP load, total load of both sending-grid and receiving-grid should be weighed first. If total load of sending-grid is smaller than that of receiving-grid, synthesis load model with IM will deteriorate post-fault EDCPS effect, and DP should be increaseed or T should be advanced appropriately.