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:
Jul. 29, 2003
Filed:
Jan. 13, 2000
Philip J. Moore, Bath, GB;
Alstom UK Ltd., Warwickshire, GB;
Abstract
Faults on power lines are detected by measuring the voltage and current at one end of a power line and using these measurements, together with values of series and shunt parameters of the line, to calculate values of voltage and current at an intermediate point on the line—the so-called “reach point”. At least the calculated voltage is used to determine whether a fault lies within a particular zone on the line. The calculation utilizes a value of a derivative of the measured current with respect to time and is able to take into account the sectioning of a line into discrete lengths corresponding to, for example, overhead and cable sections. To increase accuracy, the line or each discrete section of the line is conceptually divided into subsections each having its own parameter values. In a second aspect, detection of whether a fault lies within a particular zone involves the measurement of the voltage and current at one end of the line both before and after the fault, the calculation of a complex impedance between an intermediate point of the line and a reference point, normally earth, the use of these measured values and values relating to line parameters and to a source impedance at the second end of the line, and the determination of the sign of the complex impedance.