Patent ID: 6140634
Filing Date: 2000-10-31
Classification: G01R

Abstract:
A sensor for measuring an electrical property selected from current strength and electrical voltage in an electrical conductor having electricity flowing therein, said sensor comprising a source producing a testing light having a physical parameter; an optical transparent medium being arranged to surround the electrical conductor and in an electrical magnetic field produced by electricity flowing through the electrical conductor, said medium having a Verdet constant which will change the physical parameter of the testing light with the constant depending on the temperature of the medium and on the particular field strength of the electromagnetic field, means for directing the testing light through the medium, first evaluation means for determining corresponding modifications in the physical parameter of the testing light that has passed through the medium, a fluorescing material being arranged close to the optical transparent medium to have essentially the same temperature as the temperature of the transparent medium, said fluorescing material emitting a fluorescent light when excited by irradiation of an exciting light, said fluorescent light having an intensity that decays after termination of irradiation of the exciting light with the decay time depending on the temperature of the fluorescing material, an exciting light source for production of the intensity modulated exciting light and directing it onto the fluorescing material and a fluorescent light evaluation means for determining a decay time of the fluorescent light excited by the intensity modulated exciting light and determining the temperature of the fluorescing material based on the determined decay time of the fluorescent light with the value of the Verdet constant being determined based on the determined temperature and the value of the Verdet constant being used to determine the value of the electrical property.