Research on Aggregation Motor Model Based on Statistical Synthesis Method

With the continuous development of power system, the accuracy of load modeling is required to be higher and higher. Aggregated modeling of motors is very important for integrated load modeling. Due to the deficiency in traditional aggregation method that static loads and induction motors are assumed to be connected to the same bus, an aggregation method of load considering distribution network is presented. In this method, according to nodal voltage equation of distribution network, connection nodes were removed, while load nodes were retained. Then, according to the principle that active and reactive power losses were equivalent before and after aggregation, equivalent distribution network impedance was calculated with the retained nodes voltages and admittances of the reduced distribution network. Moreover, voltage of the fictitious bus was obtained with the voltage and injecting current of the power supply point and the equivalent distribution network. Furthermore, static loads and induction motors were displaced to the fictitious bus. Finally, according to the electromagnetic model, induction motors displaced to the fictitious bus were aggregated into a single one, and static loads were aggregated to a composite one. Because the distribution net-work impedance is considered, the aggregation model well preserves the characteristic of composite load model of distribution network. The active and reactive fitting errors are small. A case is also taken to validate that the pro-posed method can improve the simulation precision.