Modeling microgrids with voltage and frequency dependent loads

By intensifying renewable energy sources integration to the power grid and forming the microgrids (MGs) concept, many studies have been done to investigate MGs operation, control, protection, and etc. The performance of loads can play a major role in the MG behavior. Different load models can be implemented in MGs. The voltage and frequency (VF) dependent load is a substantial load model which few papers have addressed its performance in MG, so far. In islanded-mode operation of MG, there is no main grid to dictate the voltage and frequency. Considering the susceptibility of MGs to voltage and frequency variations, the proper modeling of VF dependent loads will be highly substantial in MGs. In this paper, a new method has been proposed to model the VF dependent loads in MG. Time-step simulation has been exerted to the linearized state-space equations of MG in order to obtain the eigenvalues and transient response of the system. Several case studies have been carried out on a 50 Hz MG with VF dependent load to evaluate the proper performance of this modeling.