MEASURING THE GROUND RESISTANCE OF A METALLIC STRUCTURE OR THE RESISTIVITY OF THE SOIL USING A BIG HEADED METALLIC STRUCTURE WHICH IS POSSIBLY UNDER CATHODIC PROTECTION

摘要

Method and device for measuring the ground resistance of a metal structure or the resistivity of the ground, using another large buried metallic structure, possibly under cathodic protection. The simplest measurement method according to the invention makes it possible in particular to determine the ground resistance of a metal post, using as a sole source of energy a cathode-like close channel possibly under cathodic protection, and, in the absence of currents vagrants, a voltmeter and an ammeter: - the pipeline and the coupon are electrically short-circuited with the ammeter, to measure I - the circuit is opened and the potential difference between the line and the coupon is measured (E -E ). The resistance R of the coupon towards the distant land is thus calculated as follows: The process is more precise by using two pipes, because one then gets rid of the ground resistances of the pipes. The electronic device according to the invention can implement said more precise method according to the invention, and has for this purpose at least two controllable switches and performs measurements and calculations automatically. The main industrial applications of the process according to the invention and of the device implementing it are, for example, and in a nonlimiting manner: measurement of the resistivity of the ground in the right of a metal control, making it possible to determine a cathodic polarization threshold maximum (Range: cathodic protection against corrosion) - measurement of the resistance of an electrical ground.