中文摘要：

为克服低电压暂态稳定分析过程中负荷模型无法描述掉负荷特性的缺点，在对实测数据和各种负荷的低电压特性进行研究的基础上对原有的动态负荷模型进行了改进。新模型通过增加临界电压、延迟时间和衰减系数使低电压发生时负荷按负指数形式衰减，这可以在保持负荷动态特性连续的基础上，最大限度地模拟暂态故障中因低电压掉负荷造成的负荷前后稳态不一致的现象。新模型不仅扩展了原来动态负荷模型的适用范围，而且大大提高了大扰动下暂态稳定分析的可信度。实测数据验证了模型的有效性。

英文摘要：

In order to overcome the shortage of load models used in transient stability analysis which cannot describe the load shedding characteristics under low voltage, some improvements on load models are proposed after studying the field measurement data and load characteristics under low voltage. New parameters are used in this new load model, including critical voltage delay time and attenuation coefficient. Both of these parameters can properly/describe the load shedding characteristics in negative exponent form under low voltage conditions. In this way, the steady load differences caused by low voltage disturbances can be clearly explained while keeping the load dynamic behavior successively. The improved load model not only has better properties in describing the load dynamic characteristics during the transient stability analysis but also enhances the reliability of the simulation. The field measurement data illustrate its efficiency.