CN105067962A - Low-current grounding line selection device - Google Patents

Low-current grounding line selection device Download PDF

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Publication number
CN105067962A
CN105067962A CN201510598288.1A CN201510598288A CN105067962A CN 105067962 A CN105067962 A CN 105067962A CN 201510598288 A CN201510598288 A CN 201510598288A CN 105067962 A CN105067962 A CN 105067962A
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CN
China
Prior art keywords
earthing
line selection
line
zero sequence
electric current
Prior art date
Application number
CN201510598288.1A
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Chinese (zh)
Inventor
李霞飞
张文兵
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合肥海畅电气技术有限公司
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Priority to CN201510598288.1A priority Critical patent/CN105067962A/en
Publication of CN105067962A publication Critical patent/CN105067962A/en

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Abstract

A low-current grounding line selection device is used in grounding fault line selection of a distribution network of which the neutral point is not grounded and which is grounded through a resistor or arc suppression coil. The low-current grounding line selection device comprises a zero sequence current transformer input terminal, a CPU, a CT terminal, and a zero sequence current transformer and a voltage transformer which are connected with a grounding line selection device. The grounding line selection device adopts a mode of working in which the principle of transient analysis and the wavelet technique are combined and a fundamental wave line selection method, a quintuple harmonic method, an active power method and other methods are used together. When the voltage transformer detects zero sequence voltage, a grounding loop is switched on under control, the CPU collects, analyzes and compares zero sequence currents of lines, and a grounding line is determined based on multiple criteria including current amplitude, phase and harmonic content. The accuracy of line selection is greatly improved, and especially, for the solution to the problem that line selection of an arc suppression coil system is inaccurate, test results and actual operation show that the accuracy of line selection of the low-current grounding line selection device is above 98%.

Description

A kind of Small Electric Current Earthing And Routing Device

Technical field

The present invention relates to a kind of Small Electric Current Earthing And Routing Device, particularly relate to technical field of electric power detection.

Background technology

China electrical network 35KV and following transformer station adopt isolated neutral mode or neutral by arc extinction coil grounding mode mostly, and these two kinds of earthing modes are after single-phase earthing appears in system, and the electric current flowing through earth point equals line distribution capacitance electric current, and numerical value is less.Therefore, these two kinds of earthing modes are claimed to be small current neutral grounding mode.After the advantage of small current neutral grounding system is that single-phase earthing occurs, system energy normal power supply, but due to fault signature not obvious, make rapidly, indicate ground loop to have certain difficulty exactly.

Summary of the invention

The present invention for the deficiency that prior art exists, provides a kind of Small Electric Current Earthing And Routing Device just.

For solving the problem, the technical solution used in the present invention is as follows:

A kind of Small Electric Current Earthing And Routing Device, for isolated neutral, through the earth fault line selection of the power distribution network of resistance or grounding through arc, comprise zero sequence current mutual inductor input terminal, CPU, CT holds, and the zero sequence current mutual inductor be connected with line-selected earthing device respectively and voltage transformer (VT), described line-selected earthing device adopts transient analysis principle to combine with wavelet technique, first-harmonic route selection method, quintuple harmonics method, the multiple methods such as active power method and working method, when voltage transformer (VT) detects residual voltage, control ground loop conducting, then according to CPU to circuit zero sequence current acquisition, analyze, relatively, according to the amplitude of electric current, phase place and harmonic content multicriterion differentiate ground link.

Further, the bus hop count of described line-selected earthing device is not more than three sections, and transmission line circuit sum is not more than 48 tunnels.

Further, described line-selected earthing device is provided with alarm device.

Further, described line-selected earthing device is provided with LCDs.

Further, the electric pressure of described line-selected earthing device is 380V ~ 66kV.

Compared with prior art, implementation result of the present invention is as follows in the present invention:

A kind of Small Electric Current Earthing And Routing Device of the present invention, for arc suppression coil earthing system, but is not limited to arc suppression coil system, and the route selection accuracy rate of two kinds of methods of operation all reaches domestically leading level.The frequency-selecting of quintuple harmonics arrowband, extract first-harmonic composition simultaneously, utilize its relativeness to sentence ground path and can get rid of the inconsistent misjudgement caused of zero sequence CT end characteristic, to eliminate in ground connection process system fluctuation to the impact sentencing line, substantially increase the sampling precision of 5 subharmonic, thus improve the accuracy of arc suppression coil earthing system route selection.Intrinsic signal in the middle of CPU acquisition system, amplitude is strong, and resolution is high, is widely used in 3 ~ 66kV system of the industries such as electric power, chemical industry, oil, metallurgy, coal, mine and petrochemical industry.

Accompanying drawing explanation

Fig. 1 is a kind of Small Electric Current Earthing And Routing Device structural representation of the present invention.

Embodiment

Below in conjunction with specific embodiments content of the present invention is described.

Small Electric Current Earthing And Routing Device principle of work:

(1), system zero sequence voltage raise, usual residual voltage is bordering on zero, will produce residual voltage after ground connection, this voltage numerically≤phase voltage.

(2), ungrounded circuit zero-sequence current is self capacity current value, nearly 90 degree of the advanced residual voltage of phase place.

(3), ground path zero-sequence current is maximum, is all ungrounded circuit zero-sequence current sums, nearly 90 degree of delayed phase residual voltage.

(4), without arc suppression coil for first-harmonic, 5 subharmonic, above 3 establishments; There is arc suppression coil system, 5 subharmonic are set up.

(5), above 4 not by the method for operation, load variations, stake resistance impact.

(6), have arc suppression coil system to be compensated due to first-harmonic, 5 subharmonic proportions are much larger than ungrounded circuit.

(7) the zero-sequence current real component, in ground loop is maximum.

According to above 7 points, this device starts by residual voltage, by each CPU to each circuit zero sequence current acquisition, carries out analyzing, comparing, and differentiates ground path according to the amplitude of each electric current, phase place and harmonic content multicriterion.

A kind of Small Electric Current Earthing And Routing Device structural representation of the present invention as shown in Figure 1, described Small Electric Current Earthing And Routing Device is used for isolated neutral, through the earth fault line selection of the power distribution network of resistance or grounding through arc, comprise body 1, described body 1 comprises zero sequence current mutual inductor input terminal 2, CPU3, CT end 4, and the zero sequence current mutual inductor 5 be connected with line-selected earthing device respectively and voltage transformer (VT) 5, described line-selected earthing device adopts transient analysis principle to combine with wavelet technique, first-harmonic route selection method, quintuple harmonics method, the multiple methods such as active power method and working method, when voltage transformer (VT) 6 detects residual voltage, control ground loop conducting, then according to CPU2 to circuit zero sequence current acquisition, analyze, relatively, according to the amplitude of electric current, phase place and harmonic content multicriterion differentiate ground link.

Described Small Electric Current Earthing And Routing Device, for arc suppression coil earthing system, but is not limited to arc suppression coil system, and the route selection accuracy rate of two kinds of methods of operation all reaches domestically leading level.The frequency-selecting of quintuple harmonics arrowband, extract first-harmonic composition simultaneously, utilize its relativeness to sentence ground path can get rid of zero sequence CT and hold the inconsistent misjudgement caused of 4 characteristics, to eliminate in ground connection process system fluctuation to the impact sentencing line, substantially increase the sampling precision of quintuple harmonics, thus improve the accuracy of arc suppression coil earthing system route selection.Intrinsic signal in the middle of CPU3 acquisition system, amplitude is strong, and resolution is high, is widely used in 3 ~ 66kV system of the industries such as electric power, chemical industry, oil, metallurgy, coal, mine and petrochemical industry.

The bus hop count of described line-selected earthing device is not more than three sections, and transmission line circuit sum is not more than 48 tunnels, can investigate out rapidly the fault loop in multiloop.

Described line-selected earthing device is provided with alarm device, is convenient to fault loop alarm sounds.

Described line-selected earthing device is provided with LCDs, and testing result is intuitively presented in LCDs, investigates loop of being out of order rapidly.

The foregoing is only preferred embodiment of the present invention, not in order to limit the present invention, all any amendments done within the spirit and principles in the present invention, equivalent replacement and improvement etc., all should be included within protection scope of the present invention.

Claims (5)

1. a Small Electric Current Earthing And Routing Device, for isolated neutral, through the earth fault line selection of the power distribution network of resistance or grounding through arc, it is characterized in that, comprise zero sequence current mutual inductor input terminal, CPU, CT holds, and the zero sequence current mutual inductor be connected with line-selected earthing device respectively and voltage transformer (VT), described line-selected earthing device adopts transient analysis principle to combine with wavelet technique, first-harmonic route selection method, quintuple harmonics method, the multiple methods such as active power method and working method, when voltage transformer (VT) detects residual voltage, control described ground loop conducting, then according to CPU to circuit zero sequence current acquisition, analyze, relatively, according to the amplitude of electric current, phase place and harmonic content multicriterion differentiate ground link.
2. a kind of Small Electric Current Earthing And Routing Device according to claim 1, is characterized in that, the bus hop count of described line-selected earthing device is not more than three sections, and transmission line circuit sum is not more than 48 tunnels.
3. a kind of Small Electric Current Earthing And Routing Device according to claim 1, is characterized in that, described line-selected earthing device is provided with alarm device.
4. a kind of Small Electric Current Earthing And Routing Device according to claim 1, is characterized in that, described line-selected earthing device is provided with LCDs.
5. a kind of Small Electric Current Earthing And Routing Device according to claim 1, is characterized in that, the electric pressure of described line-selected earthing device is 380V ~ 66kV.
CN201510598288.1A 2015-09-18 2015-09-18 Low-current grounding line selection device CN105067962A (en)

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Cited By (8)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN106872859A (en) * 2017-04-26 2017-06-20 山东钢铁集团日照有限公司 A kind of small current earthing wire-selecting method
CN107290627A (en) * 2017-07-01 2017-10-24 合肥东玖电气有限公司 A kind of Small Electric Current Earthing And Routing Device
CN107356840A (en) * 2017-07-01 2017-11-17 合肥东玖电气有限公司 One kind is used for earth fault Small Electric Current Earthing And Routing Device
CN107843809A (en) * 2017-10-30 2018-03-27 国网湖南省电力公司 The earthing wire-selecting method differentiated based on zero sequence
CN108196214A (en) * 2017-12-12 2018-06-22 神华集团有限责任公司 Feeder line zero sequence current mutual inductor CT polarity check methods and device
CN108732466A (en) * 2018-08-09 2018-11-02 安徽亚辉电气自动化有限公司 A kind of small current earthing wire-selecting comprehensive detection and analysis system
CN108872779A (en) * 2017-08-28 2018-11-23 武汉都市环保工程技术股份有限公司 A kind of single-phase earth fault line selection device and method
CN109917230A (en) * 2019-04-08 2019-06-21 重庆大学 The neutral point monitoring and protecting integral method of distribution net work earthing fault containing resistance eutral grounding

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CN201008095Y (en) * 2007-01-19 2008-01-16 保定博为科技有限公司 Small current grounding wire-selecting device of microcomputer
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CN101701998A (en) * 2009-11-19 2010-05-05 山东泰开自动化有限公司 Novel faulty line selection method in low current faulty grounding system
WO2011012015A1 (en) * 2009-07-29 2011-02-03 江苏省电力公司常州供电公司 Fault line selection method for small current grounding system of distribution network
CN103592571A (en) * 2013-11-08 2014-02-19 珠海威瀚科技发展有限公司 Method for achieving single-phase earth fault line selection of small current grounding system

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CN201008095Y (en) * 2007-01-19 2008-01-16 保定博为科技有限公司 Small current grounding wire-selecting device of microcomputer
CN101159376A (en) * 2007-09-26 2008-04-09 东北大学 Low current neutral grounding malfunction detection and positioning device and method
WO2011012015A1 (en) * 2009-07-29 2011-02-03 江苏省电力公司常州供电公司 Fault line selection method for small current grounding system of distribution network
CN101701998A (en) * 2009-11-19 2010-05-05 山东泰开自动化有限公司 Novel faulty line selection method in low current faulty grounding system
CN103592571A (en) * 2013-11-08 2014-02-19 珠海威瀚科技发展有限公司 Method for achieving single-phase earth fault line selection of small current grounding system

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Cited By (8)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN106872859A (en) * 2017-04-26 2017-06-20 山东钢铁集团日照有限公司 A kind of small current earthing wire-selecting method
CN107290627A (en) * 2017-07-01 2017-10-24 合肥东玖电气有限公司 A kind of Small Electric Current Earthing And Routing Device
CN107356840A (en) * 2017-07-01 2017-11-17 合肥东玖电气有限公司 One kind is used for earth fault Small Electric Current Earthing And Routing Device
CN108872779A (en) * 2017-08-28 2018-11-23 武汉都市环保工程技术股份有限公司 A kind of single-phase earth fault line selection device and method
CN107843809A (en) * 2017-10-30 2018-03-27 国网湖南省电力公司 The earthing wire-selecting method differentiated based on zero sequence
CN108196214A (en) * 2017-12-12 2018-06-22 神华集团有限责任公司 Feeder line zero sequence current mutual inductor CT polarity check methods and device
CN108732466A (en) * 2018-08-09 2018-11-02 安徽亚辉电气自动化有限公司 A kind of small current earthing wire-selecting comprehensive detection and analysis system
CN109917230A (en) * 2019-04-08 2019-06-21 重庆大学 The neutral point monitoring and protecting integral method of distribution net work earthing fault containing resistance eutral grounding

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