Explanation of the Definition of Grounding Resistance
Definition of Grounding Resistance
For example: Grounding resistance is the sum of the resistance of the grounding electrode to the ground and the resistance of the grounding lead, numerically equal to the ratio of the voltage of the grounding device to the ground to the current flowing into the ground through the grounding electrode (Cihai dictionary);
Power frequency grounding resistance is the resistance between the grounding electrode and the distant earth when power frequency current flows through the grounding device, its value is equal to the ratio of the voltage of the grounding device relative to the distant earth to the current flowing into the ground through the grounding electrode (GB/T19663-2005); Ohm's law between the grounding electrode and the distant grounding electrode with zero potential; when a grounding current I flows through a grounding electrode, the potential of the grounding electrode rises to U compared to the potential before the grounding current flows in, and U/I is taken as the grounding resistance of the grounding electrode (Japan); conventional grounding impedance is the ratio of the peak grounding voltage to the peak grounding current, which usually do not occur simultaneously; grounding terminal voltage is the potential difference between the grounding device and the distant earth (1EC62305-3), etc. From a purely physics perspective, none of the above definitions are rigorous. The reason is that grounding resistance is not a purely physical concept; it is an engineering term.