负荷特性对特高压紧急直流功率支援的影响

采用互补群能量壁垒/扩展等面积准则分析多机系统中特高压直流紧急直流功率支援(EDCPS)提高暂态稳定性的机理,研究了大扰动下恒阻抗—恒电流—恒功率(ZIP)静态负荷模型、感应电动机(IM)负荷模型对特高压EDCPS效果的影响,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、恒阻抗有功负荷及其不同比例感应电动机动态负荷对特高压EDCPS策略的影响。研究表明,大扰动下IM比ZIP负荷吸收更多有功。送、受端IM负荷对大扰动后EDCPS下的功角稳定性影响是相反的,送端改善其支援效果而受端则恶化其效果;至于全网采用综合模型后相对于ZIP模型对功角的影响,要衡量送、受端网区负荷量的大小,若送端负荷小于受端负荷则恶化支援下的功角稳定性,需适当增大直流提升量或适时提前投入功率支援。

Impacts of Load Characteristics on the UHVDC Emergency DC Power Support Strategy

The mechanism of UHVDC emergency DC power support (EDCPS) to enhance transient stability is analyzed based on the CCEBC/EEAC method. The impacts of ZIP load, IM load, load composition, and load location on the EDCPS performance following large disturbances are studied. It is found that following a large disturbance, IM load absorbs more active power than ZIP load and the influence of the sending-end IM load on the post-fault EDCPS power-angel stability is completely opposite to that of receiving-end load. The sending-end loads are helpful to enhance the system stability. In the case that the sending-end load is smaller than the receiving-end load, synthesis load tends to deteriorate the post-fault EDCPS effect, and the active power support needs to be increased or provided in good advance.