Electric circuit arrangement for standard insulation monitoring with emergency shut-down for an ungrounded power supply system upon detection of a ground fault

Patent metadata

Field	Value
Publication number	US-2022390907-A1
Application number	US-202217829942-A
Country	US
Kind code	A1
Filing date	Jun 1, 2022
Priority date	Jun 2, 2021
Publication date	Dec 8, 2022
Grant date	—

Abstract

The invention relates to an electric circuit arrangement (2) for standard insulation monitoring with emergency shut-down for an ungrounded power supply system (4) upon detection of a ground fault, having a standard insulation monitoring device (10) which is coupled to an active conductor (L1, L2, L3) of the power supply system (4) on the network side via a coupling branch (12) each or to a neutral point (S) of the power supply system (4) via a coupling branch (12) and is connected to ground (PE) on the ground side via a ground connection branch (14). The electric circuit arrangement (2) comprises an AC/DC sensitive measuring current transformer (20) which detects a fault current on the network side at the active conductors (L1, L2, L3) in the coupling branches (12) or at the neutral point (S) in the coupling branch (12) or on the ground side in the ground connection branch (14) of the insulation monitoring device (10); an evaluator (30) for evaluating the fault current with regard to a fault current threshold being exceeded; and a trip device (40) for shutting down the power supply system (4).

First claim

1 . An electric circuit arrangement ( 2 ) for standard insulation monitoring with emergency shut-down for an ungrounded power supply system ( 4 ) upon detection of a ground fault,
having a standard insulation monitoring device ( 10 ) which is coupled to an active conductor (L 1 , L 2 , L 3 ) of the power supply system ( 4 ) on the network side via a coupling branch ( 12 ) each or to a neutral point (S) of the power supply system ( 4 ) via a coupling branch ( 12 ) and is connected to ground (PE) on the ground side via a ground connection branch ( 14 ), characterized by an AC/DC sensitive measuring current transformer ( 20 ) which detects a fault current on the network side at the active conductors (L 1 , L 2 , L 3 ) in the coupling branches ( 12 ) or at the neutral point (S) in the coupling branch ( 12 ) or on the ground side in the ground connection branch ( 14 ) of the insulation monitoring device ( 10 ); an evaluator ( 30 ) for evaluating the fault current with regard to a fault current threshold being exceeded; and a trip device ( 40 ) for shutting down the power supply system ( 4 ).

2 . The electric circuit arrangement ( 2 ) according to claim 1 , characterized in that
the measuring current transformer ( 20 ) detects the fault current in the ground connection branch ( 14 ) of the insulation monitoring device ( 10 ) or in a connecting line ( 16 ) when using a coupling device ( 18 ) which is coupled to the active conductors (L 1 , L 2 , L 3 ) in the coupling branches ( 12 ) or to the neutral point (S) in the coupling branch ( 12 ) and is connected to the insulation monitoring devices ( 10 ) via the connecting line ( 16 ).

3 . The electric circuit arrangement ( 2 ) according to claim 2 , characterized in that
when using a coupling device ( 18 ) having a coupling-device ground connection ( 19 ), the measuring current transformer ( 20 ) additionally detects a coupling-device fault current flowing through the coupling-device ground connection ( 19 ) when detecting the fault current in the ground connection branch ( 14 ) of the insulation monitoring device ( 10 ).

Assignees

• Bender Gmbh & Co Kg

Inventors

• Hackl Dieter

Classifications

• G01R31/088

  Aspects of digital computing · CPC title

• G05B9/02 Primary

  electric · CPC title

• G01R31/083

  in cables, e.g. underground · CPC title

• G01R31/52

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

• G01R27/18 Primary

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