基于光伏逆变器的电网谐波阻抗测量新技术OACSTPCD

In response to the demand for grid harmonic impedance measurement in the context of new power systems,a novel grid harmonic impedance measurement method based on photovoltaic inverter is proposed.The proposed method does not disturb the power grid,does not require the installation of additional measurement equipment,and can also control grid harmonics during the impedance measurement.The method controls the photovoltaic inverter to function as a normal power generator under fundamental waves and controls it to be equivalent to a virtual resistor under harmonics.By changing the equivalent virtual harmonic resistance value of the inverter,the amplitude of the harmonic voltage at the grid connection point is measured,and combined with the least squares method to estimate the harmonic impedance amplitude of the system.The impedance measurement experiment is conducted using the hardware-in-loop real-time simulation experimental platform,and the measurement results are consistent with the set values.The measurement accuracy of the 5 th harmonic impedance of the system reaches 99％,and the measurement accuracy of the 7th harmonic impedance reaches 97％,which verifies that the proposed method can not only measure the amplitude of the system's multiple harmonic impedance,but also ensure high measurement accuracy.