Performance of Parametric Methods for Online Grid-Impedance Estimation Applied to PV Systems

This work presents an analysis of the performance of parametric methods applied for the online estimation of the grid impedance, to whose photovoltaic (PV) system is connected. The method for estimating the grid impedance consists of carrying out short-term variations of the power injected into the grid and then using numerical methods to estimate the grid impedance. In this work, the numerical methods of Newton-Raphson and Finite Differences are used. The estimated grid impedance is used to guarantee system stability. To validate the proposed methods, realtime simulations were performed. The results obtained indicate the most efficient numerical method to be incorporated into the control system.