Experimental study on transient characteristics of grounding grid for substation

Previous work has proven that transient characteristics of a grounding grid was far more different than its performance at power frequency because of the inductance of the system and the soil ionization phenomena. In this paper, a test on a grounding grid of a 110 kV substation was conducted. Several parameters, such as waveform, peak value and injecting point of lightning, were altered to study their relationship with transient characteristics. Not only the impulse earthing resistance but also the voltage and current distribution of the conductors were analyzed. Characteristics of grounding grid between power frequency and higher frequency were compared.