Circuit arrangement having an active measuring voltage for determining an insulation resistance against ground potential in an ungrounded power supply system

Patent metadata

Field	Value
Publication number	US-11353486-B2
Application number	US-202017103292-A
Country	US
Kind code	B2
Filing date	Nov 24, 2020
Priority date	Nov 28, 2019
Publication date	Jun 7, 2022
Grant date	Jun 7, 2022

Abstract

A circuit arrangement (20) having an active measuring voltage (UG) for determining an insulation resistance (RF) or a complex-valued insulation impedance (ZF) of an ungrounded power supply system (12) against ground potential (PE), the circuit arrangement (20) having a measuring path (24) which runs between an active conductor (L1, L2) of the power supply system (12) and the ground potential (PE) and includes a measuring-voltage generator (VG) for generating the measuring voltage (UG), a measuring resistance (RM) for capturing a measured voltage (UM) and a coupling resistance (RA), the circuit arrangement (20) having a signal evaluation circuit (26) which includes a signal input for evaluating the measured voltage (UM) and a ground connection (GND). The ground connection (GND) is connected to a ground potential (PE).

First claim

The invention claimed is:

1. A circuit arrangement ( 20 , 40 ) having an active measuring voltage (U G ) for determining an insulation resistance (R F ) or a complex-valued insulation impedance (Z F ) of an ungrounded power supply system ( 12 ) against ground potential (PE), the circuit arrangement ( 20 , 40 ) having a measuring path ( 24 , 44 ) which runs between an active conductor (L 1 , L 2 ) of the power supply system ( 12 ) and the ground potential (PE) and comprises a measuring-voltage generator (V G ) for generating the measuring voltage (U G ), a measuring resistance (R M ) for capturing a measured voltage (U M ) and a coupling resistance (R A ), the circuit arrangement ( 20 , 40 ) comprising a signal evaluation circuit ( 26 , 46 ) which comprises a signal input for evaluating the measured voltage (U M ) and a ground connection (GND), wherein the ground connection (GND) is connected to a ground potential (PE).

2. The circuit arrangement according to claim 1 , wherein the ground potential (PE), the measuring-voltage generator (V G ), the measuring resistance (R M ) and the coupling resistance (R A ) make up a series connection in the measuring path ( 24 ) in a first order.

3. The circuit arrangement according to claim 2 , further including a multi-pole coupling in an ungrounded power supply system ( 12 ) having at least two active conductors (L 1 , L 2 ), at least two of the active conductors (L 1 , L 2 ) each being connected to the ground potential (PE) via a measuring path ( 24 ).

4. The circuit arrangement according to claim 3 , wherein the measuring paths ( 24 ) are realized individually.

5. The circuit arrangement according to claim 3 , wherein at least two measuring paths ( 24 ) comprise a shared measuring-voltage generator (V G ).

6. The circuit arrangement according to claim 1 , wherein the ground potential (PE), the measuring resistance (R M ), the measuring-voltage generator (V G ) and the coupling resistance (R A ) make up a series connection in the measuring path ( 44 ) in a second order.

7. The circuit arrangement according to claim 6 , further including a multi-pole coupling in an ungrounded power supply system ( 12 ) having at least two active conductors (L 1 , L 2 ), at least two of the active conductors (L 1 , L 2 ) each being individually connected to the ground potential (PE) via a measuring path ( 44 ).

8. A method of using the circuit arrangement ( 20 , 40 ) having a multi-pole coupling via individual measuring paths ( 24 , 44 ) according to claim 4 , comprising causing the corresponding measuring-voltage generators (V G ) to generate different measuring voltages (U G ) to test the functionality of the couplings.

9. A method of using the circuit arrangement ( 20 , 40 ) comprising a multi-pole coupling via individual measuring paths ( 24 , 44 ) according to claim 4 , comprising simultaneous active measuring of a corresponding insulation resistance (R F ) or a complex-valued insulation impedance (Z F ) against ground potential (PE) in several ungrounded power supply systems ( 12 ), active conductors (L 1 , L 2 ) of different power supply systems ( 12 ) being assigned to the measuring paths ( 24 , 44 ).

10. The method according to claim 9 , where different measuring voltages (U G ) are applied to the corresponding power supply systems ( 12 ) for identifying a low-impedance connection between the power supply systems ( 12 ).

Assignees

• Bender Gmbh & Co Kg

Inventors

• Schaefer Oliver
• Macht Burkhard

Classifications

• G01R27/08

  Measuring resistance by measuring both voltage and current · 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

• G01R27/025 Primary

  Measuring very high resistances, e.g. isolation resistances, i.e. megohm-meters · CPC title

• G01R31/00

  Arrangements for testing electric properties; Arrangements for locating electric faults; Arrangements for electrical testing characterised by what is being tested not provided for elsewhere ({measuring superconductive properties G01R33/1238;} testing line transmission systems H04B3/46; testing or measuring semiconductors or solid state devices during manufacture {H10P74/00}) · CPC title