CN107345994A - A kind of apparatus and method for improving small current earthing wire-selecting precision - Google Patents
A kind of apparatus and method for improving small current earthing wire-selecting precision Download PDFInfo
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- CN107345994A CN107345994A CN201610289830.XA CN201610289830A CN107345994A CN 107345994 A CN107345994 A CN 107345994A CN 201610289830 A CN201610289830 A CN 201610289830A CN 107345994 A CN107345994 A CN 107345994A
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- scaling circuit
- current
- integrator
- voltage signal
- earthing wire
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- 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
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- General Physics & Mathematics (AREA)
- Testing Of Short-Circuits, Discontinuities, Leakage, Or Incorrect Line Connections (AREA)
Abstract
The present invention provides a kind of apparatus and method for improving small current earthing wire-selecting precision, belongs to power measurement field.A kind of device for improving small current earthing wire-selecting precision includes：Three Rogowski coils, three integrators, scaling circuit and scaling circuit.A kind of method for accurately measuring zero-sequence current precision, is mainly included the following steps that：S1, three Rogowski coils measure the alternating current in A, B, C phase of supply line respectively, and induce voltage signal and export to integrator；S2, the voltage signal are reduced into the voltage signal consistent with AC current waveform and output by the integrator；S3, scaling circuit receive the voltage signal of the integrator reduction and calculate zero-sequence current and export to scaling circuit；The zero-sequence current is enlarged into electric signal by S4, the scaling circuit.The present invention realize safely, be accurately detected compared with small grounding current, so as to precisely judging earth fault line.
Description
Technical field
The present invention relates to power measurement field, more particularly to a kind of device for improving small current earthing wire-selecting precision
And method.
Background technology
When singlephase earth fault occurs for neutral point non-direct grounding system, earth point will be produced by ground path
Raw capacitive earth current.If this capacitance current is quite big, intermittent electric arc will be produced in earth point, drawn
Play overvoltage.In order to suppress electric arc, arc suppression coil is installed in neutral point, utilizes the inductance current of arc suppression coil
Capacity current during compensation of ground, reduces earth-fault current, so that automatic blow-out, ensures power supply safety.
Due to the compensation of arc suppression coil so that the electric current very little of ground connection, this causes existing zero sequence current mutual inductor very
Hardly possible accurately detects, and current zero sequence current mutual inductor can only detect power frequency component.
The content of the invention
It is an object of the invention to provide a kind of apparatus and method for improving small current earthing wire-selecting precision, so that
Solve foregoing problems present in prior art.
To achieve these goals, the technical solution adopted by the present invention is as follows：
A kind of device for improving small current earthing wire-selecting precision, including：Three Rogowski coils, three integrators,
Scaling circuit and scaling circuit；
Wherein, three Rogowski coils are respectively fitted in the A phases, B phases and C phases of supply line, described three
The output end of Rogowski coil connects the input of three integrators, the output of three integrators respectively
End connects the scaling circuit, and the scaling circuit connects the scaling circuit.
Preferably, the frequency of Rogowski coil measurement alternating current is from 0.1Hz to 1MHz, and measurement range is from several
MA to hundreds of kA, measurement accuracy is up to 0.1%.
Preferably, between the Rogowski coil and the integrator, the integrator and the scaling circuit
Between, between the scaling circuit and the scaling circuit connected by shielded cable.
Preferably, the scaling circuit connection Small Electric Current Earthing And Routing Device.
A kind of application improves the method that the device of small current earthing wire-selecting precision measures zero-sequence current precision, bag
Include following steps：
S1, three Rogowski coils measure the alternating current in A, B, C phase of supply line respectively, and induce
Voltage signal；
S2, the Rogowski coil are exported the voltage signal by shielded cable to three integrators respectively
Input；
S3, the voltage signal are reduced into the voltage consistent with the AC current waveform measured by the integrator
Signal, exported by the integrator output terminal；
S4, the voltage signal exported by the integrator output terminal are exported to scaling circuit, and by described
Scaling circuit calculates zero-sequence current；
S5, the zero-sequence current calculated by the scaling circuit are exported to scaling circuit, passing ratio
Amplifying circuit amplifies the electric signal for ease of teletransmission；
S6, the electric signal after being amplified by scaling circuit, teletransmission to Small Electric Current Earthing And Routing Device.
The beneficial effects of the invention are as follows：The present invention uses three Rogowski coils, measures the electricity of every circuit respectively
The signal of various different frequencies on circuit can be acquired by stream, Rogowski coil in real time, then pass through ratio
Example operational loop, calculates the zero-sequence current of circuit, then in passing ratio amplifying circuit, small-signal is put
Greatly, teletransmission is then carried out to low current wiring line selection apparatus, and ground connection event is accurately judged from the signal of amplification
Hinder circuit, realize safely, be accurately detected less earth current, so as to precisely judge ground connection therefore
Hinder circuit.
Brief description of the drawings
Fig. 1 is the device structural map that small current earthing wire-selecting measurement zero-sequence current precision is improved in the present invention.
Embodiment
In order to make the purpose , technical scheme and advantage of the present invention be clearer, below in conjunction with accompanying drawing, to this
Invention is further elaborated.It should be appreciated that embodiment described herein is only solving
The present invention is released, is not intended to limit the present invention.
1st, a kind of construction of device for improving small current earthing wire-selecting precision and its installation
(1) three Rogowski coils are respectively fitted in the A phases, B phases and C phases of supply line；
(2) output end of three Rogowski coils is coupled with three integrators；
(3) three integrators A, B and C output signal are connected on scaling circuit；
(4) output signal after scaling circuit is calculated is connected on scaling circuit；
(5) signal after amplification, teletransmission to Small Electric Current Earthing And Routing Device.
2nd, a kind of method for accurately measuring zero-sequence current precision
(1) three high-precision rogowski coils are utilized, coil is respectively fitted over to the electricity of A, B, C phase of supply line
On cable, coil can with measurement frequency less than 0.1Hz to up to 1MHz alternating current, measurement range is from several
MA to hundreds of kA, precision can reach 0.1%.Coil has splendid transient response ability.
(2) voltage signal for inducing three Rogowski coils, three products are coupled with by shielded cable
Divide the input of device.
(3) voltage signal induced is reduced into the voltage signal consistent with measurement current waveform by integrator,
Exported by integrator output terminal.
The voltage signal of (4) three integrator output, while scaling circuit is accessed, three road voltage signals
Passing ratio computing circuit calculates zero-sequence current.
(5) zero-sequence current calculated by scaling circuit, export to scaling circuit, passing ratio
Amplifying circuit amplifies the electric signal for ease of teletransmission.
By using above-mentioned technical proposal disclosed by the invention, following beneficial effect has been obtained：The present invention uses
Three Rogowski coils, measure the electric current of every circuit respectively, and Rogowski coil can be by the various differences on circuit
The signal of frequency is acquired in real time, then passing ratio operational loop, calculates the zero-sequence current of circuit,
Then in passing ratio amplifying circuit, by low level signal amplification, then carry out teletransmission to low current wiring route selection and fill
Put, accurately judge earth fault line from the signal of amplification, realize safely, be accurately detected compared with
Small earth current, so as to precisely judge earth fault line.
Described above is only the preferred embodiment of the present invention, it is noted that for the common skill of the art
For art personnel, under the premise without departing from the principles of the invention, some improvements and modifications can also be made, this
A little improvements and modifications should also regard protection scope of the present invention.
Claims (5)
- A kind of 1. device for improving small current earthing wire-selecting precision, it is characterised in that including：Three Roche lines Circle, three integrators, scaling circuit and scaling circuit；Wherein, three Rogowski coils point It is not enclosed in the A phases, B phases and C phases of supply line, the output ends of three Rogowski coils connects described respectively The input of three integrators, the output end of three integrators connects the scaling circuit, described Scaling circuit connects the scaling circuit.
- A kind of 2. device for improving small current earthing wire-selecting precision according to claim 1, it is characterised in that The frequency of Rogowski coil measurement alternating current from 0.1Hz to 1MHz, measurement range from several mA to hundreds of kA, Measurement accuracy is up to 0.1%.
- A kind of 3. device for improving small current earthing wire-selecting precision according to claim 1, it is characterised in that Between the Rogowski coil and the integrator, between the integrator and the scaling circuit, it is described Between scaling circuit and the scaling circuit connected by shielded cable.
- A kind of 4. device for improving small current earthing wire-selecting precision according to claim 1, it is characterised in that The scaling circuit connects Small Electric Current Earthing And Routing Device.
- 5. a kind of application improves the method that the device of small current earthing wire-selecting precision measures zero-sequence current precision, It is characterised in that it includes following steps：S1, three Rogowski coils measure the alternating current in A, B, C phase of supply line respectively, and induce Voltage signal；S2, the Rogowski coil are exported the voltage signal by shielded cable to three integrators respectively Input；S3, the voltage signal are reduced into the voltage consistent with the AC current waveform measured by the integrator Signal, exported by the integrator output terminal；S4, the voltage signal exported by the integrator output terminal are exported to scaling circuit, and by described Scaling circuit calculates zero-sequence current；S5, the zero-sequence current calculated by the scaling circuit are exported to scaling circuit, passing ratio Amplifying circuit amplifies the electric signal for ease of teletransmission；S6, the electric signal after being amplified by scaling circuit, teletransmission to Small Electric Current Earthing And Routing Device.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201610289830.XA CN107345994A (en) | 2016-05-05 | 2016-05-05 | A kind of apparatus and method for improving small current earthing wire-selecting precision |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201610289830.XA CN107345994A (en) | 2016-05-05 | 2016-05-05 | A kind of apparatus and method for improving small current earthing wire-selecting precision |
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| CN107345994A true CN107345994A (en) | 2017-11-14 |
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| CN201610289830.XA Pending CN107345994A (en) | 2016-05-05 | 2016-05-05 | A kind of apparatus and method for improving small current earthing wire-selecting precision |
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Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| WO2021163888A1 (en) * | 2020-02-18 | 2021-08-26 | 西门子股份公司 | Ground fault detection method, device, and system for electric power system |
| CN113702768A (en) * | 2021-08-31 | 2021-11-26 | 许昌智能继电器股份有限公司 | Line selection method and line selection controller suitable for low-current grounding |
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| CN101159376A (en) * | 2007-09-26 | 2008-04-09 | 东北大学 | Low current neutral grounding malfunction detection and positioning device and method |
| CN101404404A (en) * | 2008-11-19 | 2009-04-08 | 马云涌 | Demarcation breaker for vector-synthesis zero sequence current |
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| CN102590700A (en) * | 2011-12-23 | 2012-07-18 | 山东电力集团公司淄博供电公司 | Method and device for quickly locating faults of overhead line on basis of time synchronization |
| US8264215B1 (en) * | 2009-12-10 | 2012-09-11 | The Boeing Company | Onboard electrical current sensing system |
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| CN104101812A (en) * | 2013-04-09 | 2014-10-15 | 北京映翰通网络技术股份有限公司 | Single-phase grounding fault detection and positioning method and system for low-current grounding power distribution network |
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- 2016-05-05 CN CN201610289830.XA patent/CN107345994A/en active Pending
Patent Citations (8)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN101159376A (en) * | 2007-09-26 | 2008-04-09 | 东北大学 | Low current neutral grounding malfunction detection and positioning device and method |
| CN101404404A (en) * | 2008-11-19 | 2009-04-08 | 马云涌 | Demarcation breaker for vector-synthesis zero sequence current |
| CN101846717A (en) * | 2009-03-27 | 2010-09-29 | 北海银河科技继保电气有限公司 | Low-current ground fault line selection device |
| US8264215B1 (en) * | 2009-12-10 | 2012-09-11 | The Boeing Company | Onboard electrical current sensing system |
| CN102590700A (en) * | 2011-12-23 | 2012-07-18 | 山东电力集团公司淄博供电公司 | Method and device for quickly locating faults of overhead line on basis of time synchronization |
| CN104076243A (en) * | 2013-03-29 | 2014-10-01 | 北京映翰通网络技术股份有限公司 | Method for detection and indication of single-phase ground faults of small current grounding power distribution network and device |
| CN104101812A (en) * | 2013-04-09 | 2014-10-15 | 北京映翰通网络技术股份有限公司 | Single-phase grounding fault detection and positioning method and system for low-current grounding power distribution network |
| CN103389423A (en) * | 2013-07-23 | 2013-11-13 | 山西乐普节能技术有限公司 | Power quality analyzer |
Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| WO2021163888A1 (en) * | 2020-02-18 | 2021-08-26 | 西门子股份公司 | Ground fault detection method, device, and system for electric power system |
| CN113702768A (en) * | 2021-08-31 | 2021-11-26 | 许昌智能继电器股份有限公司 | Line selection method and line selection controller suitable for low-current grounding |
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Application publication date: 20171114 |