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:
Mar. 07, 2006
Filed:
Jun. 07, 2001
Per Larsson, Vastersas, SE;
Magnus Backman, Vasteras, SE;
Lars Jonsson, Vasteras, SE;
ABB Group Services Center AB, Vasteras, SE;
Abstract
An apparatus () for detecting a zero-crossing of an alternating current after occurrence of a fault in a current path () for determining a suitable time for opening an electric switching device () arranged in the current path for breaking the current in the current path comprises members () adapted to detect the current in the current path. An arrangement () is adapted to calculate the dc-level of the current and the decay of the dc-level with time on the basis of values of the alternating current detected and also predict the time for a future zero-crossing of the alternating current on the basis of at least current values obtained through said current detection, the dc-level calculated, the dc-decay calculated and information about the period time of the alternating current.