Error compensation for current transformer sensors
AssigneeMagnelab, Inc.
InventorsGeorge O. Langer, Christopher Scott Brown, Samad Seyfi
Life of this patent
Estimating the term…
Abstract
Phase angle error and ratio error correction is provided in a current transformer by a bucking voltage opposite in phase to the voltage drop across the burden resistor and inherent winding resistance.
Claims8
Current transformer apparatus comprising a secondary circuit with a secondary winding connected to a burden resistance and a bucking voltage generator circuit positioned between the secondary winding and the burden resistance, wherein the bucking voltage generator provides a bucking voltage in the secondary circuit that actively and effectively reduces or cancels total resistance in the secondary circuit resulting from inherent winding resistance and the burden resistance.
A method of increasing measuring accuracy of a current transformer that has a magnetic core in which an input alternating current to be measured produces a magnetic field and in which the magnetic field induces a secondary alternating current in a secondary winding on the magnetic core to flow in a secondary circuit through a burden resistance in the secondary circuit to produce a voltage drop that is indicative of the input alternating current, comprising applying a bucking voltage in the secondary circuit that actively and effectively reduces or cancels total resistance in the secondary circuit resulting from inherent winding resistance and the burden resistance.
Dependencies are inferred from the claim text.