Single-phase harmonic impedance measuring method based on square wave signals

The invention discloses a single-phase harmonic impedance measuring method based on square wave signals. The single-phase harmonic impedance measuring method based on square wave signals comprises the steps: simplifying a low voltage power grid system into a series circuit; determining an access point in the series circuit, and accessing the voltage of the access point for the open circuit of an accurate measurement device; accessing a harmonic current generator; and using the harmonic current generator to inject harmonic currents with the amplitude with a square wave change of 12.5Hz every time in order, so that the harmonic voltage of every time can be accurately measured and then the harmonic impedance of every time can be accurately calculated.