A Comparison of Typical Non-invasive Method for Utility Harmonic Impedance Estimation

The proliferation of power electronic equipment brings lots of problems to the power system, one of them is harmonic. Harmonic impedance is an essential parameter to evaluate the harmonic emission level and distinguish the harmonic responsibility when the harmonic level exceeds planning levels. At present, there are a lot of methods to estimate utility harmonic impedance, divided into invasive method and non-invasive method. In this paper, some typical non-invasive methods have been compared, and the simulation system is built in the MATLAB. The background harmonic fluctuation and the different values of utility and customer harmonic impedances are considered to evaluate the performance of the typical non-invasive methods. The simulation results proved that the complex ICA method is the most robust to the background harmonic fluctuation than other methods, but in some special cases, the method based on data selection has a better performance.