A Novel Measurement-Based Dynamic Equivalent Model of Grid-Connected Microgrids

For transient stability studies of power systems with high penetration of microgrids, models of the connected microgrids must be used. In this paper, a novel dynamic equivalent model is proposed for grid-connected microgrids using measurement data of point of common coupling (PCC). The proposed equivalent model includes electrical components, such as synchronous generator (SG), voltage source converter (VSC), and active and reactive loads. The proposed equivalent model contains different controllers, such as excitation system, governor, and VSC's controllers. All SG-based distributed generation (DG) units of the microgrid are represented by one equivalent SG, while an equivalent VSC represents converters-based DGs. Similarly, a parallel active and reactive static load is considered in the equivalent model to represent the static loads of the microgrid. In order to make the equivalent model more efficient, accurate, and valid at different operating points, a series resistance and reactance are utilized to connect the equivalent generator to the PCC. The final goal is to identify the parameters of the equivalent components such that the equivalent model behaves as like as the detailed microgrid facing different disturbances. The identification procedure is carried out by means of a genetic algorithm using measurement data at the PCC. To show the effectiveness and accuracy of the proposed model, the identified equivalent model is studied at different operating points and the results are compared with the original detailed model.