Bender Gmbh & Co Kg

Carsten Hartmann

Dieter Hackl

Oliver Schaefer

Helmut Becker

Oliver Schäfer

Dipl-Ing Dieter Hackl

A method and monitoring device for selectively determining partial insulation resistance and partial system leakage capacitance of an outgoing line in a branched ungrounded power supply system monitored using an insulation monitoring device actively superposing a measuring alternating voltage on the ungrounded power supply system. Using an equivalent circuit diagram of the branched ungrounded power supply system as a basis, the partial insulation resistance having the current/voltage ratios applicable in linear systems are derived from the known measuring voltage and the inner resistance of the insulation monitoring device and from the total insulation resistance and the stationary partial current measured in the corresponding outgoing line and in the settled state. To calculate the partial system leakage capacitance, the temporal derivative of the measured non-stationary conductor-to-ground voltage is evaluated in conjunction with the non-stationary partial current and the previously determined partial insulation resistance.

Method and monitoring device for determining a partial insulation resistance and a partial system leakage capacitance in a branched ungrounded power supply system

The invention relates to insulation fault location systems and methods for insulation fault location for an ungrounded DC power supply system, which is redundantly fed from a first direct voltage supply source coupled to diodes and a second direct voltage supply source coupled to diodes and to which a consumer is redundantly coupled. Due to the diode coupling and the asymmetric current splitting of the load current associated therewith, non-compensational partial currents arise in the supply lines in such a power supply system and consequently differential current portions, which can be captured by measuring current transformers and which can interfere with a valid test current during an insulation fault location. In order to eliminate the interfering differential current portions, compensating measures on the primary side are proposed in the measuring current transformers and indirect compensating measures on the secondary side are proposed in an insulation fault location apparatus.

Insulation fault location systems and methods for insulation fault location for a redundant DC power supply system coupled to diodes

The invention relates to a method for insulation fault location as well as to an insulation fault location system for an ungrounded power supply system. The main idea of the present invention rests upon the idea that while preserving a predetermined maximally admissible test current amplitude, a test current pulse duration of a test current is adaptively set such that all interfering values are eliminated in a captured differential current, in particular the leakage currents arising in consequence of large supply leakage capacitances. Should a test of the value of the final value of the differential current reveal that a test current threshold value has been exceeded, this exceedance can be seen as an indicator that the respective conductor section is therefore in the fault circuit.

Method for insulation fault location and an insulation fault location system for an ungrounded power supply system

Insulation fault location systems and methods are for insulation fault location for an ungrounded DC power supply system, which is redundantly fed from a first direct voltage supply source coupled to diodes and a second direct voltage supply source coupled to diodes and to which a consumer is redundantly coupled. Due to the diode coupling and the asymmetric current splitting of the load current associated therewith, non-compensational partial currents arise in the supply lines in such a power supply system and consequently differential current portions, which can be captured by measuring current transformers and which can interfere with a valid test current during an insulation fault location. In order to eliminate the interfering differential current portions, compensating measures on the primary side are proposed in the measuring current transformers and indirect compensating measures on the secondary side are proposed in an insulation fault location apparatus.

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Schotten, Germany

Carsten Hartmann