Insulation monitoring device for simultaneously monitoring network sections of an ungrounded power supply system

Patent metadata

Field	Value
Publication number	US-9594110-B2
Application number	US-201514600104-A
Country	US
Kind code	B2
Filing date	Jan 20, 2015
Priority date	Jan 21, 2014
Publication date	Mar 14, 2017
Grant date	Mar 14, 2017

Abstract

The invention relates to an insulation monitoring device for simultaneously monitoring an ungrounded power supply system comprising network sections that can be interconnected via coupling switches, comprising a signal generator for generating a measuring signal and a coupling circuit for coupling the measuring signal to the power supply system. According to the invention, the insulation monitoring device comprises a coupling circuit for each interconnectable network section to be monitored, a switchable electrical connecting element being arranged for connecting adjacent coupling circuits.

First claim

The invention claimed is:

1. An insulation monitoring device ( 2 ) for monitoring an ungrounded power supply system ( 4 ) comprising network sections ( 4 a , 4 b , 4 c ) that are switchably interconnected via operable coupling switches ( 6 a , 6 b ) in order to constantly monitor an insulation resistance against ground of the network sections ( 4 a , 4 b , 4 c ) both in a separated and simultaneously in an interconnected state, comprising a signal generator ( 14 ) for constantly generating a measuring signal and a coupling circuit ( 12 a , 12 b , 12 c ) for coupling the measuring signal to the power supply system ( 4 ), characterized in that the coupling circuit ( 12 a , 12 b , 12 c ) is provided for each network section ( 4 a , 4 b , 4 c ) to be monitored and that a switchable electrical connecting element ( 22 a , 22 b ) is arranged for connecting adjacent coupling circuits ( 12 a , 12 b , 12 c ).

2. The insulation monitoring device ( 2 ) according to claim 1 , characterized in that the coupling circuit ( 12 a , 12 b , 12 c ) comprises a coupling resistance ( 16 a , 16 b , 16 c ) for connection to each active conductor of the network section ( 4 a , 4 b , 4 c ) and a measuring resistance ( 18 a , 18 b , 18 c ) connected in series with the coupling resistance ( 16 a , 16 b , 16 c ).

3. The insulation monitoring device ( 2 ) according to claim 2 , characterized in that the coupling circuit ( 12 a , 12 b , 12 c ) comprises a signal evaluation unit ( 20 a , 20 b , 20 c ) for evaluating the measured value of the measuring signal that is tapped via the measuring resistance ( 18 a , 18 b , 18 c ).

4. The insulation monitoring device ( 2 ) according to claim 2 , characterized in that connection points of the connecting element ( 22 a , 22 b ) are arranged between the coupling resistances ( 16 a , 16 b , 16 c ) and the measuring resistance ( 18 a , 18 b , 18 c ) of the respective coupling circuits ( 12 a , 12 b , 12 c ).

5. The insulation monitoring device ( 2 ) according to claim 2 , characterized in that the coupling circuit ( 12 a , 12 b , 12 c ) is configured for evaluating the measured value of the measuring signal that is tapped via the measuring resistance ( 18 a , 18 b , 18 c ).

Assignees

• Bender Gmbh & Co Kg

Inventors

• Lehr Mario
• Weiss Carsten
• Jaeger Hans-Juergen

Classifications

• G01R27/18

  Measuring resistance to earth {, i.e. line to ground} · CPC title

• H02H3/17

  by means of an auxiliary voltage injected into the installation to be protected {(using summation current transformers H02H3/33)} · CPC title

• G01R31/1272 Primary

  of cable, line or wire insulation, e.g. using partial discharge measurements (locating faults in cables G01R31/083) · CPC title

• G01R31/025

  Physics · mapped topic

• G01R31/52 Primary

  Testing for short-circuits, leakage current or ground faults · CPC title