电力系统受扰轨迹的差异度及其在参数识别中的应用

Difference Degree of Power System Disturbed Trajectories and Its Applications in Parameter Identification

受扰轨迹完整地反映了模型及参数对系统动态行为的影响。基于稳定性机理,提出电力系统受扰轨迹的机理差异度。该指标值随动态行为差异的增大而增加;当且仅当该指标值为0时,2组受扰轨迹完全重合。据此,可量化不同动态行为的接近程度,用以校核模型,并通过灵敏度分析来识别参数。通过仿真,验证了该指标的有效性,揭示出多参数识别问题中普遍存在的本质多解现象,其解依赖于初值和迭代策略。强调必须以不同扰动作为激励,分别识别参数,并指出系统识别的困难大大超出现有的认识。

Disturbed trajectories fully reflect the effects on system dynamic behavior of both models and parameters.Based on the stability mechanism,a mechanism difference degree is proposed as an index of power system disturbed trajectories.The index increases as the difference of dynamic behaviors increases between two scenario trajectories.The two trajectories completely overlap if and only if the index is zero.Therefore,the proximity of the different dynamic behaviors can be quantified,which can be used to verify models and identify parameters through sensitivity analysis.The simulation studies show the efficiency of the index.An essential phenomenon of multi-solution in multi-parameter identification is revealed,so that the identification result depends on both the initial value and search strategy.Different excitation disturbances are required for parameter identification.This paper explores the complexity of system identification,which is far beyond existing knowledge.