Verfahren zum Durchführen von Distanzmessungen an einer elektrischen Hochspannungsübertragungsleitung

摘要

The invention concerns a method for the measurement of distances along a high-tension power-transmission line, the method calling for measurements of the current and voltage in the power-transmission line to be digitalized and then processed in a digital filter unit consisting of two linear-phase, non-recursive FIR filters of a first type and at least one FIR filter of a second type. The individual weighting factors are predetermined independently, and an error correction carried out by applying a correction factor. From the processed output values from the filter unit, a computing unit determines parameters from which an impedance indicating the distance to the location of a fault can be deduced. In order to be able to obtain accurate distance measurements in the shortest possible time, the invention calls for the digitized measured values (u, x) in the filter unit (1) to be processed in two further FIR filters (8, 9) of a third type to determine, from the output signals from these FIR filters (8, 9), a reference impedance (Zv). The distance measurement is considered to be sufficiently accurate if the difference betweem the measured impedance (Zm) and the reference impedance (Zv) is less than a given value.