A Novel Calibration Method for Ampere’s Law-Based Current Measuring Instruments

In this paper, a new kind of calibration method for current measuring instruments based on Ampere´s law (current transformers, current clamps, Rogowsky probes, and so on) is proposed. The method focuses in the uncertainty associated to the geometric variability of the circuits where the current is to be measured and it does not require to perform any mechanical displacements of the instrument. It is based on the fact that the relevant magnetic effect of a circuit over a measuring instrument is the tangential component of the magnetic strength along the Ampere´s law integration path. This effect can be recreated by the sum of the magnetic effects of a set of predefined circuits, each one excited by a specific current (and different for each circuit to recreate). The method also offers a graphical representation of the instrument response variability when off center indefinite straight wires are applied. An experimental setup and finite-element method simulations have been used to check the results.