The patent badge is an abbreviated version of the USPTO patent document. The patent badge does contain a link to the full patent document.
The patent badge is an abbreviated version of the USPTO patent document. The patent badge covers the following: Patent number, Date patent was issued, Date patent was filed, Title of the patent, Applicant, Inventor, Assignee, Attorney firm, Primary examiner, Assistant examiner, CPCs, and Abstract. The patent badge does contain a link to the full patent document (in Adobe Acrobat format, aka pdf). To download or print any patent click here.
Patent No.:
Date of Patent:
Jan. 18, 2011
Filed:
Aug. 24, 2006
Zoran Gajic, Västerås, SE;
Zoran Gajic, Västerås, SE;
ABB Technology Ltd., Zürich, CH;
Abstract
A method and a device for fault detection in an n-winding, three-phase power transformer. For each of the windings (Wi) the three phase currents (I; I; I) are measured. For each of the windings (Wi) deciding if a zero sequence current (I) reduction is to be performed depending on at least one user setting (k) and if so, deducting the zero sequence current (I) from each of the three phase currents (I; I; I). For each of the windings (Wi) generating normalized currents by performing a magnitude compensation and a phase angle shift compensation on the results of the previous step. For each of the three phases (Lx) comparing the normalized current of a single winding with the normalized currents of all other windings. For each phase (Lx) generating a fault signal, if a difference between the single winding (W) and all other windings (W, . . . , Wn) exceeds a predefined level.