We measure the ground resistance for photovoltaic systems with the auxiliary potential probe which does not be placed on the same line with the earth electrode and the auxiliary current probe. The auxiliary current probe needs to be placed out of the area of PV system when the frame of the system works as earth electrodes. The shape and resistance value of the current probe determine the suitable distance between the current probe and the potential one and the suitable distance between the current probe and earth electrodes. We also try applying the hyperbolic function to the measured resistance values near the PV system to estimate the earth resistance. These procedures also works for floating PV systems.
