Bender Gmbh & Co Kg

Pascal Becker

Karl Schepp

Dieter Hackl

Oliver Schaefer

Oliver Schäfer

A method and an electric circuit arrangement for determining a branch insulation resistance and a branch leakage capacitance of a line branch to be monitored in a branched, ungrounded power supply system having active conductors and a measuring voltage fed centrally by a controllable measuring voltage source and a residual current caused by the measuring voltage being registered using a current sensor in the line branch to be monitored. The centrally supplied measuring voltage is formed over a generator period having a characteristic signal form defined via the frequency composition. By this (frequency) modulation of the measuring voltage, information is transmitted from the central feed location of the measuring voltage to the current sensor disposed in the line branch to be monitored. Based on this information, the current sensor can establish with which resistance value the coupling circuit feeds the measuring voltage in the corresponding generator period, without another communication channel being required.

Method and electric circuit arrangement for determining a branch insulation resistance and a branch leakage capacitance in an ungrounded power supply system

The invention relates to a method and a device for identifying and locating cyclic momentary insulation faults in an ungrounded power supply system, the method comprising the steps: detecting a fault current caused by the momentary insulation fault as a differential current in the branch circuit to be monitored and displaying the temporal progression of the differential current via a differential current signal by means of a differential current sensor; providing a processing signal which temporally describes a process sequence of a process taking place in the consumer; correlating the differential current signal with the processing signal in a computing unit in order to yield a correlation signal as a measure for a temporal match between the differential current signal and the processing signal; signaling the momentary insulation fault via the computing unit by means of a signaling signal if the correlation signal shows the temporal match. The device according to the invention has a differential current sensor and a computing unit so that it can implement the method according to the invention.

Method and device for identifying and locating cyclic momentary insulation faults in an underground power supply system

A grounded socket and a method for insulation fault location in an ungrounded power supply system including insulation monitoring by a standard insulation monitoring device superimposing a measuring voltage on the ungrounded power supply system for determining an insulation resistance of the ungrounded power supply system. The grounded socket includes a housing having electrical contacts, a signaling device for signaling an insulation state, and a current measuring device for detecting and evaluating a differential current, the current measuring device having a measuring current transformer and evaluating electronics, and the current measuring device being configured for high-resolution detection and evaluation of a measuring current driven by the measuring voltage as a differential measuring current.

Grounded socket and method for insulation fault location in an ungrounded power supply system including insulation monitoring

An electric circuit arrangement and a measuring method for a galvanically insulated, AC/DC sensitive differential current measurement having a high resolution having: a toroid current transformer having at least one secondary winding for detecting a differential current; a driver circuit for powering the secondary winding; a first oscillator circuit for controlling the driver circuit and for generating a time-modulated binary oscillator signal having dwell times in a state 1 and a state 2; a second oscillator circuit for determining the corresponding dwell time in the states 1 and 2 in high resolution by means of a clock signal having a clock rate independent of the oscillator signal; an evaluation device for evaluating the dwell time; and a data interface for outputting a differential-current measuring value; the driver circuit and the second oscillator circuit each being realized as structurally individual, integrated circuits.

Electric circuit arrangement and a method for a galvanically insulated, AC/DC sensitive differential-current measurement having high resolution

A method and device for determining a division of a total insulation resistance and of a total system leakage capacitance in an ungrounded power supply system. The basic idea is to determine how the total insulation resistance is divided into partial insulation resistances and how the total system leakage capacitance is divided into partial system leakage capacitances between the active conductors of the ungrounded power supply system from displacement voltages measured between each of the active conductors of the ungrounded power supply system based on values determined in advance for the total insulation resistance and for the total system leakage capacitance of the ungrounded power supply system. By evaluating the displacement voltages in terms of their changes in amplitude, their frequency and their phasing, conclusions can be drawn as to the division of the total insulation resistance and of the total system leakage capacitance between the individual active conductors.

Method and device for determining the division of a total insulation resistance and the division of a total system leakage capacitance in an ungrounded power supply system

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Gruenberg, Germany

Pascal Becker