Evaluation of Harmonic Voltage Emission Level Considering Harmonic Impedance of Photovoltaic Side

Abstract

Considering that when the photovoltaic inverters are connected to the grid through filters, the harmonic impedance at the photovoltaic side of the common connection points may not satisfy the condition that the harmonic impedance at the photovoltaic side is much larger than that at the background side(which is satisfied in the traditional grid), so that when estimating the harmonic voltage emission level, the influence of the harmonic impedance on the photovoltaic side can not be neglected. A method for evaluating the harmonic voltage emission level considering the harmonic impedance on the photovoltaic side is proposed. Firstly, the harmonic impedance of photovoltaic side is estimated according to the parameters of photovoltaic inverters, filters and lines. Then, the harmonic voltage emission level is evaluated based on the estimated harmonic impedance of photovoltaic side. Finally, the advanced and accuracy of the proposed method is verified by simulation and comparison with other methods.