Apparatus for current measurement by means of the faraday effect

Claim 1

IN A DEVICE FOR THE MEASUREMENT OF AN ELECTRICAL CURRENT FLOWING IN AN AERIAL HIGH-VOLTAGE CONDUCTOR OF THE TYPE COMPRISING A DEVICE FOR MODULATING THE INTENSITY OF A POLARIZED LIGHT BEAM, A FIRST FARADAY EFFECT DEVICE DISPOSED IN THE VICINITY OF SAID CONDUCTOR AND INCLUDING A FIRST MAGNETO-OPTICALLY ACTIVE BODY DISPOSED TO BE TRAVERSED BY SAID POLARIZED LIGHT BEAM, FIRST ELECTRICALLY CONDUCTING MEANS EXCITED BY SAID CURRENT AND CREATING A MAGNETIC FIELD IN SAID FIRST BODY TO PRODUCE A ROTATION OF THE PLANE OF POLARIZATION OF SAID LIGHT BEAM, A SECOND FARADAY EFFECT DEVICE LOCATED IN THE VICINITY OF THE GROUND AND COMPRISING A SECOND MAGNETO-OPTICALLY ACTIVE BODY DISPOSED TO BE TRAVERSED BY THE LIGHT BEAM EMERGING FROM SAID FIRST BODY, SECOND ELECTRICALLY CONDUCTING MEANS EXCITED BY A COMPENSATING CURRENT ANT CREATING A MAGNETIC FIELD IN SAID SECOND BODY TO PRODUCE A COMPENSATING ROTATION OF THE PLANE OF POLARIZATION OF SAID LIGHT BEAM IN OPPOSITE DIRECTION TO THE DIRECTION OF ROTATION PRODUCED IN SAID FIRST BODY, MEANS INCLUDING AN ELECTRONIC AMPLIFIER TO PRODUCE SAID COMPENSATING CURRENT, OPTICAL DIVIDING MEANS TO DIVIDE THE POLARIZED LIGHT BEAM EMERGING FROM SAID SECOND BODY INTO TWO ELEMENTARY LIGHT BEAMS, A FIRST PHOTOELECTRIC DEVICE COLLECTING THE LIGHT FLUX OF THE ELEMENTARY LIGHT BEAM BEING TRANSMITTED BY SAID DIVIDING MEANS, A SECOND PHOTO-ELECTRIC DEVICE COLLECTING THE LIGHT FLUX OF THE ELEMENTARY LIGHT BEAM BEING REFLECTED BY SAID DIVIDING MEANS, AN ELECTRONIC BALANCING DEVICE, SAID FIRST AND SECOND PHOTO-ELECTRIC DEVICES BEING ELECTRICALLY CONNECTED IN OPPOSITION AND TO SAID BALANCING DEVICE, THE OUTPUT OF SAID BALANCING DEVICE BEING CONNECTED TO SAID AMPLIFIER.