Transient Impedance of the Synchronous Generator Grounding Electrode due to Short Circuit Current

This paper presents a novel approach for the calculation of the transient impedance of the horizontal electrode used as a synchronous generator grounding. When a short circuit occurs in the network, corresponding short-circuit current acts as an excitation source of the horizontal grounding electrode. Both short-circuit current and horizontal electrode impulse response, are defined in the time domain in a closed form representation. Transient impedance calculation is based on the novel derivation of the closed form time domain solution for short-current excitation. Some illustrative numerical results are provided, taking into account various parameters of the grounding system.