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:
Oct. 15, 2002

Filed:

Dec. 29, 2000
Applicant:
Inventors:

Yi Hu, Cary, NC (US);

David Lubkeman, Raleigh, NC (US);

Reto Buettner, Erlenbach, CH;

David Hart, Raleigh, NC (US);

Assignee:
Attorney:
Primary Examiner:
Int. Cl.
CPC ...
G01R 3/108 ;
U.S. Cl.
CPC ...
G01R 3/108 ;
Abstract

A fault is located in a transmission line with a sending end, a receiving end, and a tapped load connected to the transmission line at a tap node. The tap node divides the transmission line into a sending side and a receiving side. The sending end and the receiving end each include a measuring device. The fault location is determined by obtaining measured circuit parameters including measured pre-fault and faulted current and voltage values at the sending end and at the receiving end of the transmission line. The phase angle difference due to unsynchronized measurement using the measured pre-fault current and the measured pre-fault voltage values may be calculated. The load impedance of the tapped load is calculated. A first fault location is calculated assuming that the fault is located on the sending side of the tap node. A second fault location is calculated assuming that the fault is located on the receiving side of the tap node. The fault location is selected from one of the first fault location and the second fault location, by selecting the fault location having a value within a predetermined range representing a full distance between two nodes.


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