Characteristic vector of differential equation load model and its case study on statistics analysis

Load model plays important role in the dynamic simulation of power system. The time-varying property of load in short-time appears to be stochastic in long-term. Thus the approach in this paper to study the statistical regularity of load characteristic vector, based on probability distribution and statistics, gives references to the choice and application of load model and its parameters. This paper proposes the following approaches. First, the differential equation model is transformed into continuous state space model, and is solved for the time-domain response curve against step input. Second, the characteristic parameters of response curve, represented by [k_t, T_f, k_s], are distilled as the characteristic vector of load property. 69 sets of effective sampling data from Yuzhuang substation of Cangzhou region in China were studied for the character parameters of load model, from which useful conclusions of the load model variety regularity have been got.