The paper presents a method for replacing two cylindrical surfaces having a common axis, situated at the same potential, with a distribution of punctual charges placed on the common axis. This allows the computation of the capacitance of the two conductors, with applications in determining the resistance of the cylindrical earth electrode. The model is used in verifying the precision of a practical formula for these electrodes.

Keywords: Field synthesis, Electrical images, Capacitance, Earth electrodes