A Low-order Simplified Model of Power-electronic-interfaced Loads

In recent years, an increasing number of power loads have shown the characteristics of power electronics, and large quantities of electric equipment are connected to the power network through power electronic devices, which profoundly changes the load characteristics of nodes. However, the existing load model cannot well describe its dynamic characteristics. Based on the analysis of load characteristics, a low-order simplified model of power-electronic-interfaced loads is proposed. The model describes the relationship between the active power, reactive power, and bus voltage in the form of transfer functions. It has the advantages of a simple structure and few parameters to be identified. Furthermore, a static load component is added to the model to characterize the power change characteristics during the voltage sag stage. The simulation results show that the simplified model has good universality, high fitting accuracy and adaptability to different voltage sags.