Method and error location in branched low voltage and medium voltage networks and evaluation circuit used thereof

Abstract

The invention relates to a method for error location in branched low voltage and medium voltage networks and to an evaluation network used therefor. The inventive method consists of the following steps: initially, the frequency of the low-frequency component of the impulse wave current or voltage is determined; the circuit inductance is calculated, using a Thomson resonant circuit formula, from the determined low-frequency transient frequency with the known capacitance of the impulse capacitor; the inductance of the impulse capacitor and the measuring line is deducted as a correction factor; finally the distance from the place of error in the cable is calculated from the inductance thus calculated on the basis of the inductance of the measured object, the advantage thereof being that it is possible to located voltage-dependent cable errors in a branched low-voltage or medium voltage network by means of length determination in a quick and error-free manner without signal reflections causing disturbances on branches or end points of the cable. The evaluation circuit is provided with a conditioning and protection component, an A/D converter and at least one memory unit, in addition to an evaluation computer for the signal.