EP2601535A2 - Method and device for parasitic current detection - Google Patents
Method and device for parasitic current detectionInfo
- Publication number
- EP2601535A2 EP2601535A2 EP11751840.7A EP11751840A EP2601535A2 EP 2601535 A2 EP2601535 A2 EP 2601535A2 EP 11751840 A EP11751840 A EP 11751840A EP 2601535 A2 EP2601535 A2 EP 2601535A2
- Authority
- EP
- European Patent Office
- Prior art keywords
- current
- potential
- power supply
- comparison
- power
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Withdrawn
Links
Classifications
-
- G—PHYSICS
- G01—MEASURING; TESTING
- G01R—MEASURING ELECTRIC VARIABLES; MEASURING MAGNETIC VARIABLES
- 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
- G01R31/40—Testing power supplies
-
- G—PHYSICS
- G01—MEASURING; TESTING
- G01R—MEASURING ELECTRIC VARIABLES; MEASURING MAGNETIC VARIABLES
- G01R15/00—Details of measuring arrangements of the types provided for in groups G01R17/00 - G01R29/00, G01R33/00 - G01R33/26 or G01R35/00
- G01R15/14—Adaptations providing voltage or current isolation, e.g. for high-voltage or high-current networks
- G01R15/146—Measuring arrangements for current not covered by other subgroups of G01R15/14, e.g. using current dividers, shunts, or measuring a voltage drop
- G01R15/148—Measuring arrangements for current not covered by other subgroups of G01R15/14, e.g. using current dividers, shunts, or measuring a voltage drop involving the measuring of a magnetic field or electric field
-
- G—PHYSICS
- G01—MEASURING; TESTING
- G01R—MEASURING ELECTRIC VARIABLES; MEASURING MAGNETIC VARIABLES
- 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
- G01R31/50—Testing of electric apparatus, lines, cables or components for short-circuits, continuity, leakage current or incorrect line connections
- G01R31/52—Testing for short-circuits, leakage current or ground faults
Definitions
- the invention relates to a method for Fremdstromdetekti ⁇ on in a power supply system, the at least one electrical device, a power grid with line paths for supplying the device and a central electrical
- Feed-in device for feeding electrical power into the power grid, wherein the feed device is connected to a first of the line paths to which a reference potential is applied and connected to at least a second of the line paths, to which a potential for generating an operating current through the device is ⁇ wherein the first conduction path by means of a DEFINE ⁇ th first grounding a feeder directly to the
- Feed device connected and otherwise
- the invention further relates to a Vorrich ⁇ processing for performing the method.
- power supply systems are used whose reference potential is once connected to ground.
- So z. B. 24 volt DC systems with positive potential for generating an operating current and grounded negative potential as a reference potential widely used.
- 230 volt AC systems are known in which the voltage applied to the neutral reference potential (neutral potential) is grounded at least ei ⁇ ner point (TN or TT systems).
- the grounded reference potential z. B.
- the aforementioned monitoring device detects this stream. As soon as a fixed threshold value is exceeded, signaling takes place.
- this detection method has the disadvantage that occurring in practice unavoidable superimposed alternating ⁇ currents caused z.
- EMC filters and by the natural intrinsic capacity of piping systems and directions, such as the electrical device and the feed device can lead to false signals.
- a ground fault of the operationally non-grounded potential for generating the operating current also leads in this case to a possible false signalization.
- the invention is therefore based on the object to provide a method for external current detection and an apparatus for carrying out this method, which can distinguish signals caused by superimposed alternating currents of Fremdströ ⁇ men (non-systemic streams).
- the external current (system-external current) is determined by comparing the operating current with a ground leakage current flowing through the earthing branch.
- the earth leakage current flowing through the grounding branch is determined, and the operating current in the second line path is determined by current measurement.
- This Be ⁇ mood and this determination be made dynamically, ie as a continuous or quasi-continuous Bestim ⁇ tion / investigation.
- the dynamics are preferably characterized by a frequency range from 0 Hz to about 1 kHz.
- the method enables a practical solution which "fades out” capacitively coupled or isolated (external) currents into the reference potential of the power supply system and, depending on the instantaneous value of the operating current of the supply system, a dynamic reference variable for comparison with the current flowing through the earthing feeder. short-circuit current, ie in the line between reference potential and earth.
- the determination of the operating current (load ⁇ current) of the power supply system by current measurement on at least one directly connected to the feed device and otherwise unbranched connection portion of the second line path.
- the output of a sensor for the determination of the Erdungsab ⁇ branch flowing through grounding circuit current is proportional to a current operating voltage value for Be ⁇ operating current actual value proportional voltage value and the output of a device for determining the operating current. Both voltage values are converted in particular by means of associated voltage divider into comparable sizes.
- the comparison means ei ⁇ ner comparator circuit is performed with a comparator.
- the comparator circuit preferably has thepolstei ⁇ ler.
- the outputs of the two voltage dividers are on guided the inputs of the comparator.
- the comparator be ⁇ true for external current detection, the difference of the corresponding sizes.
- the voltage value proportional to the operating current is a dynamic reference variable and the voltage value proportional to the grounding current is a value which is compared with this dynamic reference variable.
- a border a threshold comparison result triggers a signal output and / or a secure ⁇ standardized measure of the power system.
- several threshold values are provided. For example, at a first threshold where the deviation (difference) is small, a signal: "maintenance advised" is output. Reasons for such a deviation are z. B. excessively high leakage currents and / or creeping
- the power supply system is a DC voltage system in which the potential difference between the potential for generating the current flow and its reference potential is substantially constant.
- the phrase "substantially constant" allows load-related voltage fluctuations, which can always occur in such systems, in particular.
- the feed device is an inverter or has a converter.
- the power supply system is an AC system in which the reference potential of a a Neut ⁇ ralleiterpotential, in particular a grounded Neutrallei ⁇ terpotential (TN or TT-System), and the at least one potential for generating the current flow around the reference potential is periodically varying phase potential.
- the AC voltage system can be a single-phase AC voltage system or a multi-phase AC voltage system.
- a typical multiphase AC system is a three-phase system.
- the feed device is a transformer or a
- the device according to the invention for carrying out the above-mentioned method comprises: (a) an all-current-sensitive sensor for determining the earth leakage current flowing through the ground branch, (b) a device for measuring current at the at least one connection section of the second line path and for determining the operating current. current from it, and (c) a comparator circuit having a
- the current-actual value detection of the sensor and / or the device for measuring current is all-current-sensitive, ie sensitive to DC and AC components.
- the comparator circuit is before in Trains t ⁇ a microcontroller ( ⁇ ) realized which continue towards modules for signal processing and signal evaluation.
- the device has two voltage dividers whose outputs are connected to inputs of the signal ⁇ technically comparator.
- the comparator circuit thus has two comparators upstream voltage divider, which are preferably electronically programmable.
- these are connected by means of a potentiometer / (DIP) switch re ⁇ alelle.
- the device has an evaluation unit for evaluating the comparison variable by comparison with a predeterminable one
- the evaluation unit outputs a signal, for example to a signal output device, if the comparison variable exceeds the threshold value.
- the device is suitable for detection in a dynamic range from 0 Hz to at least 2 kHz, preferably from 0 Hz to at least 20 kHz. Due to the capacitive grounding, foreign currents typically occur in this frequency spectrum.
- the device is not only generally appro ⁇ net, but advantageously also concretely set up to carry out the above-mentioned method.
- Allstrom-sensitive sensor is rich ⁇ tet for the determination of the earthing branch flowing through Erdungs gleichtroms.
- the device for measuring current is set up for current measurement at the at least one further connection section of the second line path and for determining the operating current therefrom. The decor of the
- Comparator circuit is set up for determining the first variable proportional to the ground-fault current and the second variable proportional to the determined operating current, and the comparator of the comparator circuit is set up to compare the two variables.
- the invention also relates to a feed and external current detection device which has the feed device and the abovementioned device for carrying out the said method for detecting foreign current.
- Infeed device and device for external current detection are arranged in particular in a common housing of the feed and external current detection device.
- Fig. 1 shows a power supply system with an electrical
- Fig. 2 shows the power supply system of FIG. 1 with a multi-capacitive grounded reference potential and
- Fig. 3 shows the power supply system of FIG. 1 with a
- FIG. 1 shows a power supply system 10 with a central electrical feed device 12 for feeding electrical power into a power grid 14 of the power supply system 10.
- a plurality of electrical ⁇ cal devices 16 are interconnected by the power grid 14 in the power grid 14 .
- Feeding device 12 are supplied with power.
- the power grid 14 is designed as a DC power grid 14 and has two line paths 18, 20.
- the first conductive path 18 a as a negative potential ( "negative potential") from ⁇ formed reference potential cpl is present and is located at the second Lei ⁇ processing path 20 a with respect to the reference potential cpl hö ⁇ heres potential cp2 ( "positive potential") for generating an operating current through the power grid 14 at.
- the power grid 14 is thus a supplied from a constant voltage power grid.
- the reference path cpl having the first conduction path 18 is connected by means of a defined grounding 22 at a point 24 to ground potential.
- the ground tap 22 is part ei ⁇ nes otherwise unbranched terminal portion 26 of the first conduction path 18th
- FIG. 2 shows the power supply system 10 in a range from the feed device 12 to a first device.
- the first conducting path 18 with the reference potential ⁇ cpl is not only via the defined grounding branch 22, but also capacitively via a line capacitance 28 connected to ground potential at another location 24 ⁇ and a device capacity 30 with ground potential at a further Stel ⁇ le 24 ⁇ ⁇ .
- the different points of the ground potential 24, 24 24 ⁇ ⁇ are in turn electrically connected through (specific) earth resistances 32 each other so that three external power circuits 34, 36, 38, so-called ground loops ⁇ arise.
- Each of these external current circuits 34, 36, 38 passes through the earthing branch 22.
- FIG. 3 now shows the same section of the power supply system 10 as FIG. 2, wherein instead of the external current circuits 34, 36, 38, the device 40 for external current detection is shown.
- the device 40 at a wide ⁇ ren unbranched terminal portion 44 is a means for current measurement and determination of the operating current 46.
- the device 40 further comprises a comparator circuit 48 with a device 50 for determining a first size VI proportional to the earth leakage current and one for
- the sizes are in the example voltage ⁇ sizes.
- the device 50 has two voltage dividers 54, 56 for adapting the two variables.
- the external current is determined by a dynamic comparison of the operating current with a Erdungs gleichstrom flowing through the grounding branch 22.
- the proportion of the earth leakage current is nale first variable VI determined by means of the sensor 42 and the second operating variable proportional to the determined operating current V2 determined by means for measuring current 46, both sizes VI, V2 by means of the device 50 adapted to each other and compared by means of the comparator 52 by subtracting each other.
- the device 50 comprises two voltage dividers 54, 56 for adapting the variables VI, V2 formed as voltage variables.
- the comparison result is in turn compared to a threshold value S by means of an evaluation unit 58. This is connected to a signal output 60 and thus connected therewith, that these outputs a signal when the threshold value S on ⁇ border comparison result.
- This signal is z. For example, suppose that multiple earthing is to be assumed within the power supply system 10.
- the method according to the invention describes a practice-oriented solution for "masking out” capacitively coupled or decoupled currents in the line of the power supply system 10 with the reference potential cp2, for this purpose a function of the instantaneous value of the operating current (operating current actual value ) a dynamic Füh ⁇ proxy for the evaluation unit 58 of the current detection formed in the earthing branch. This command is compared in the evaluation unit 58 with individually predeterminable relati ⁇ ven threshold values. Upon reaching and / or exceeding these thresholds signaling is triggered by means of the signal edition 60.
- the maximum permissible size of the leakage currents caused by EMC filters in the high-current range is 1 mA per kW.
- EMC an occurring in total leakage current at 0.5 to 1% of the operating current than at present angenom ⁇ men. If the current operating current of a Strom fixturesssys ⁇ system 10 is taken as a base value and derived therefrom, a relative threshold, for. B. 1% or 2%, is selected, the operating current following dynamic adjustment of this threshold occurs.
- a relative threshold for. B. 1% or 2%
- non-preventive fire protection 300 mA
- protection against electrical shock 30 mA
- the risk of ner operationally unrecognized risk of effects of injected external currents in the frequency range from DC to the lower MHz range (destruction of hardware and signal corruption by superimposed voltages that can lead to misconduct).
- the procedure can be applied both to existing plants and to new plants.
- the device 40 is to bring into the system interconnection of the power supply system 10 ⁇
- the evaluation unit 54 may be separately angeord ⁇ net. The same applies for use in new plants.
- Feeding device 12 power grid 14
Landscapes
- Physics & Mathematics (AREA)
- General Physics & Mathematics (AREA)
- Emergency Protection Circuit Devices (AREA)
- Testing Of Short-Circuits, Discontinuities, Leakage, Or Incorrect Line Connections (AREA)
- Direct Current Feeding And Distribution (AREA)
Abstract
Description
Claims
Applications Claiming Priority (2)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
DE102010036847.4A DE102010036847B4 (en) | 2010-08-04 | 2010-08-04 | Method and device for external current detection |
PCT/EP2011/063381 WO2012017015A2 (en) | 2010-08-04 | 2011-08-03 | Method and device for parasitic current detection |
Publications (1)
Publication Number | Publication Date |
---|---|
EP2601535A2 true EP2601535A2 (en) | 2013-06-12 |
Family
ID=44545688
Family Applications (1)
Application Number | Title | Priority Date | Filing Date |
---|---|---|---|
EP11751840.7A Withdrawn EP2601535A2 (en) | 2010-08-04 | 2011-08-03 | Method and device for parasitic current detection |
Country Status (5)
Country | Link |
---|---|
US (1) | US20130141136A1 (en) |
EP (1) | EP2601535A2 (en) |
CN (1) | CN103069287B (en) |
DE (1) | DE102010036847B4 (en) |
WO (1) | WO2012017015A2 (en) |
Families Citing this family (6)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
DE102014205918A1 (en) * | 2014-03-31 | 2015-10-01 | Robert Bosch Gmbh | Method for testing an isolation device |
DE102014210290A1 (en) * | 2014-05-30 | 2015-12-03 | Bender Gmbh & Co. Kg | METHOD AND DEVICE FOR MONITORING A PROTECTIVE LADDER CONNECTION |
DE102014224639A1 (en) * | 2014-12-02 | 2016-06-02 | Robert Bosch Gmbh | Method and monitoring device for detecting a fault current for a control device for controlling a multiphase actuator |
DE102017202191A1 (en) * | 2017-02-13 | 2018-08-16 | Robert Bosch Gmbh | Circuit and method for detecting a creeping short circuit in bridge circuits |
CN108021943B (en) * | 2017-12-06 | 2020-06-16 | 北京上格云技术有限公司 | Method and device for detecting power supply of electromechanical device |
CN108333411B (en) * | 2018-01-12 | 2020-06-16 | 上海华虹宏力半导体制造有限公司 | Circuit and method for reducing analog voltage measurement error |
Family Cites Families (7)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
GB2318002A (en) * | 1996-10-02 | 1998-04-08 | Melvyn Webster | Earth leakage current sensor |
ES2196582T3 (en) * | 1997-06-17 | 2003-12-16 | Walther Bender Gmbh & Co Kg Di | PROCEDURE AND DEVICE FOR CONTROLLING INSULATION AND LACK CURRENT IN AN ALTERNATE CURRENT ELECTRICAL NETWORK. |
AU755700B2 (en) * | 1999-11-29 | 2002-12-19 | Canon Kabushiki Kaisha | Power generation system, and method for installing the same |
JP2003098215A (en) * | 2001-09-26 | 2003-04-03 | Canon Inc | Earth detection method and device in power conversion system |
TW538570B (en) * | 2001-12-06 | 2003-06-21 | Prolific Technology Inc | Power protection apparatus |
CN201159747Y (en) * | 2008-02-03 | 2008-12-03 | 深圳艾科创新微电子有限公司 | Inductor current sensing circuit for switch power source |
EP2157437B1 (en) * | 2008-08-19 | 2015-08-19 | SMA Solar Technology AG | Method for measuring a current, particularly through an earthing device |
-
2010
- 2010-08-04 DE DE102010036847.4A patent/DE102010036847B4/en not_active Expired - Fee Related
-
2011
- 2011-08-03 WO PCT/EP2011/063381 patent/WO2012017015A2/en active Application Filing
- 2011-08-03 EP EP11751840.7A patent/EP2601535A2/en not_active Withdrawn
- 2011-08-03 CN CN201180038314.5A patent/CN103069287B/en not_active Expired - Fee Related
-
2013
- 2013-02-04 US US13/758,161 patent/US20130141136A1/en not_active Abandoned
Non-Patent Citations (1)
Title |
---|
See references of WO2012017015A2 * |
Also Published As
Publication number | Publication date |
---|---|
DE102010036847B4 (en) | 2015-01-08 |
CN103069287A (en) | 2013-04-24 |
WO2012017015A3 (en) | 2012-04-05 |
US20130141136A1 (en) | 2013-06-06 |
WO2012017015A2 (en) | 2012-02-09 |
DE102010036847A1 (en) | 2012-02-09 |
CN103069287B (en) | 2016-03-02 |
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