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.

Date of Patent:
May. 24, 2016

Filed:

Sep. 27, 2012
Applicant:

Sma Solar Technology Ag, Niestetal, DE;

Inventors:

Gerd Bettenwort, Kassel, DE;

Sebastian Bieniek, Niestetal, DE;

Lutz Eidenmueller, Brombachtal, DE;

Olaf Proeve, Hann. Muenden, DE;

Assignee:

SMA SOLAR TECHNOLOGY AG, Niestetal, DE;

Attorney:
Primary Examiner:
Assistant Examiner:
Int. Cl.
CPC ...
G01R 31/14 (2006.01); H02H 3/33 (2006.01); H02H 3/16 (2006.01);
U.S. Cl.
CPC ...
H02H 3/337 (2013.01); H02H 3/16 (2013.01);
Abstract

For the purpose of determining a fault current component of a differential current which is measured as a current sum over a plurality of lines carrying a current of an AC current generator, an electric signal which depends on generator voltages present at the AC current generator with respect to earth potential and which is in phase with a leakage current component of the differential current is generated. The electric signal is scaled by multiplying it by a scaling factor; and the scaled electric signal is subtracted from the differential current to obtain a remainder. The scaling factor is repeatedly updated such that the effective value of the remainder reaches a minimum at the present value of the scaling factor.


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