Patent Number: 6,311,307

Title: Digital current differential system

Abstract: A method of detecting faults on a power transmission line system includes simultaneously measuring phase current samples at each phase of each transmission terminal; calculating real and imaginary phaselets comprising partial sums of the phase current samples; for each phaselet, calculating a respective partial sum of squares of each phase current sample; calculating the sums of the real and imaginary phaselets over a variable size sliding sample window; calculating real and imaginary phasor components from the phaselets and a sum of the partial sums of the squares over the sample window; using the sums of the real and imaginary phaselets, the real and imaginary phasor components, and the sum of the partial sums of the squares to calculate a sum of squares of errors between the phase current samples and a fitted sine wave representative of the real and imaginary phasor components; using the sum of squares of errors to calculate a variance matrix defining an elliptical uncertainty region; determining whether a disturbance has occurred, and, if so, re-initializing the sample window; and determining whether a sum of current phasors from each terminal for a respective phase falls outside of the elliptical uncertainty region for the respective phase.

Inventors: Adamiak; Mark Gerard (Paoli, PA), Alexander; George Edmund (Wallingford, PA), Premerlani; William James (Scotia, NY), Saulnier; Emilie Thorbjorg (Rexford, NY), Yazici; Birsen (Clifton Park, NY)

Assignee: General Electric Company

International Classification: G01R 19/25 (20060101); H02H 3/26 (20060101); H02H 3/40 (20060101); H02H 3/28 (20060101); H02H 7/26 (20060101); H02H 7/04 (20060101); H02H 7/045 (20060101); H02H 3/05 (20060101); G06F 011/00 ()

Expiration Date: 10/30/2018