Patent ID: 6559652
Filing Date: 2003-05-06
Classification: H02H

Abstract:
A method of correcting measurements from current transformers disposed at inputs and outputs of a current node defined by an area and by a phase of a set of busbars, intended to limit the risk of unnecessary tripping of a differential phase current protection system, said differential protection system calculating the vector sum of the currents to determine the differential current between the inputs and outputs of said area in the course of regular tests, which method is based on a statistical balancing method using measured current vectors each obtained from a measurement of the current and the relative phase of the real current vector supplied at the time of each test by a current transformer, and it uses at the time of at least one test an iterative convergence algorithm for determining from the erroneous differential current vector formed by the sum of the measured current vectors the correction vector to be applied to each measured current to obtain a corrected current vector substantially equal to the real current vector, in order to correct statistically said erroneous differential current vector.