Sweep Frequency Impedance and Amplitude Frequency Response Test Technology of Substation Grounding Grid

At present, there are some inherent defects in the method of diagnosing the fault state of the substation grounding grid. It is challenging to improve because this paper starts with a new idea, based on a 35 kV substation grounding grid, and proposes a sweep frequency impedance and amplitude frequency response test method for the substation grounding grid. First, it analyzes the characteristics of sweep frequency impedance and amplitude-frequency response and how to use differences to detect faults. It proposes to use normal conditions to calculate correlation coefficients as the basis for evaluating fault status. Eight different types of defects are set under two specifications of 8 m×8 m (2 m equal interval) and 28 m×25 m (unequal interval). The test results show that when the conductor of the grounding grid is broken, the sweep frequency voltage waveform and amplitude frequency response curve are slightly different from those without defects. However, there are still problems with other defects. On the whole, this method can be used to consider the fault state of the substation grounding grid.