负荷模型对含UHVDC的多落点电网直流恢复特性的影响

负荷模型对电网暂态稳定性特别是对电压稳定性影响甚深,为了解负荷模型对含特高压直流的多直流落点电网直流动态恢复特性的影响,研究了扰动下ZIP静态负荷模型、感应电动机负荷模型(IM)的多回直流恢复特性,深入分析了送、受端网区ZIP静态负荷模型中不同比例的恒功率有功负荷、恒电流有功负荷、恒阻抗有功负荷、感应电动机模型负荷和IM欠压保护切除和恢复重接入特性等对多落点直流动态特性的影响并分析比较了南方电网典型IM模型和IEEE6型IM模型对直流恢复特性的影响,引入多馈入交互因子(MIIF)指标分析故障下直流换流站间动态交互影响作用。研究结果表明:送端和受端负荷模型对直流恢复特性的影响效果相反;大扰动下当电压跌落在一定范围内时,受端典型IM模型在改善功角稳定性方面占优,而无论送、受端,IEEE6型在弱化系统电压稳定性方面都占优。

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.