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:
Dec. 01, 1987
Filed:
Dec. 17, 1985
Leopold Blahous, Wettingen, CH;
Gerhard Linhofer, Baden, CH;
BBC Brown, Boveri & Company, Limited, Baden, CH;
Abstract
Absorption circuits (C.sub.f,L.sub.F) are used for filtering out unwanted harmonic currents in electric lines (R, S, T), particularly for rated power within the range of 1 MVar-1 GVar, for example in the case of high-voltage direct-current transmission systems. So that the absorption circuit holds the virtual capacitance of the filter capacitor circuit (C.sub.f) at its rated value at a tuned frequency even when one or more capacitors (C11, C21, C12, C22) fail, a compensating choke (L) is provided in the cross branch of an 'H' circuit of the capacitors. The capacitance of each capacitor (C11 . . . C22) is equal to the total capacitance C of the filter capacitor circuit (C.sub.f). The inductance L of the compensating choke (L) is equal to 1/.omega..sup.2 C, where .omega.=angular frequency of the harmonic. The compensating choke (L) can be designed for 5%-10% of the power of the filter choke (L.sub.F). Instead of in the cross branch, the compensating choke can also be connected between two series-connected capacitors (C12, C 22) in series with these capacitors.