| 摘要 |
<p>The invention is about an arrangement for measuring a current, with a current transducer of the Rogowski type (9) and a transducer electronics (13), wherein the current transducer (9)has a primary conductor winding (14) having a first number of loops (N1) for carrying the rated current (i R (t)) to be measured, a secondary conductor winding (16) having a pair of second terminals (17,18) and a helical shape and a second number of loops (N2), said secondary conductor winding (16) encircling the primary conductor (14) in a toroidal manner, characterised by a third conductor winding (10) having a pair of third terminals (11, 12) with a third number of loops (N3), wherein the third conductor winding is adapted to receive a calibration current signal (i cal (t)), wherein the secondary conductor winding (16) is adapted to induce between its pair of second terminals (17,18) a voltage signal V S ', said voltage signal V S ' containing the coil sensitivity S and being a superposition of a rated current voltage signal (V S ), in response to the derivative of the rated current (di R (t)/dt), and an additional calibration signal (V cal ) in response to the derivative of the calibration current signal (i cal (t)), and the transducer electronics (13) being adapted to amplify both the current voltage signal (V S ) and the calibration signal (V cal ) in the same amplifier and to divide the amplified current voltage signal by that part of the amplified calibration signal that contains the coil sensitivity and the gain</p> |
