A Quantitative Credibility Evaluation Method of Dynamic Equivalent Model Based on Power Sensitivity

In order to assess the validity of power system dynamic equivalent model accurately,a quantitative credibility evaluation method based on power sensitivity is proposed.The basic concept of power sensitivity of a power system is introduced and the power sensitivity matrix for a power system considering induction motors is derived.It is found that the dynamical responses of power system are essentially determined by the transmitting power sensitivities between dynamical components.The relationship between power sensitivity matrices of the original and equivalent systems is analyzed according to the characteristics of the equivalent system.Power sensitivity errors in the study system and the external system are given and the credibility of the equivalent model is defined.Finally,this credibility evaluation method is tested with the IEEE 10-machine 39-bus system.The credibility of different equivalent models is calculated respectively.Simulation results show that the depicted credibility index reflects validity of the equivalent models precisely and quantitatively.It can effectively distinguish different equivalent models.This method is suitable for equivalent model validations with very low computational costs.