CN103278737A - Direct-current self-injection type small-current grounding and route selecting system and method - Google Patents

Direct-current self-injection type small-current grounding and route selecting system and method Download PDF

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Publication number
CN103278737A
CN103278737A CN2013101468673A CN201310146867A CN103278737A CN 103278737 A CN103278737 A CN 103278737A CN 2013101468673 A CN2013101468673 A CN 2013101468673A CN 201310146867 A CN201310146867 A CN 201310146867A CN 103278737 A CN103278737 A CN 103278737A
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China
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direct
direct current
current
current signal
self
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CN2013101468673A
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Chinese (zh)
Inventor
张春雷
董智君
马洪
王振东
慈润宁
佟越波
李晓志
王化月
李卫
刘涛
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河北兆联电气设备科技有限公司
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Priority to CN2013101468673A priority Critical patent/CN103278737A/en
Publication of CN103278737A publication Critical patent/CN103278737A/en

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Abstract

The invention provides a commonly-known direct-current self-injection type small-current grounding and route selecting system and method, which are applicable to trouble shooting of single-phase earth faults of a non-effective grounding system of a radiation type middle-voltage power grid and a low-voltage power distribution IT (Information Technology) system. The system comprises a direct-current signal collection unit, a signal processing and displaying unit, a direct-current signal automatic injection unit and a power supply transformer neutral point processing unit. According to the commonly-known direct-current self-injection type small-current grounding and route selecting system and method disclosed by the invention, under the realization condition of applying an electromagnetic voltage transformer, an injection method of a direct-current signal is simplified; special direct-current power supply equipment does not need to be arranged and the direct-current signal is not injected into a power grid under a normal operation condition; and only if the single-phase earth faults happen, the direct-current signal is automatically injected into the power grid, and the injection is simple and reliable and is easy to realize. A self-injection manner after half-wave rectification of zero sequence voltage is ingeniously utilized.

Description

A kind of system and method for direct current self-filled type small current earthing wire-selecting
Technical field
The present invention relates to a kind of system and method for small current earthing wire-selecting, especially a kind of system and method for direct current self-filled type small current earthing wire-selecting.
Background technology
Medium voltage network system with non-effectively earthed neutral (comprise isolated neutral, through grounding through arc with through high resistance ground) and low-voltage distribution IT system, having the band of permission singlephase earth fault moves in short-term, the advantage of uninterrupted power supply, but the investigation of singlephase earth fault is difficulty relatively, the safe operation of puzzlement system.
The little electric current line selection apparatus that extensively adopts is used the principle that first-harmonic, triple harmonic current direction or amplitude relatively reach the two combination at present.Be 90 ° of the zero-sequence current hysteresis residual voltages of fault loop, its amplitude is non-fault loop capacitance current sum; 90 ° of the leading residual voltages of the zero-sequence current of non-fault loop, its amplitude is the amplitude of self-generated electricity capacitance current.Yet the single-phase earthing degree significantly influences phase relation between zero-sequence current and the residual voltage and the amplitude of zero-sequence current.So through the fault of transition resistance eutral grounding, often judge by accident because of the difference of transition resistance (ground connection degree).This is the inaccurate main cause of present little electric current route selection.
In recent years, the someone proposed injection direct current additional supply, cooperated the little electric current selection method of photoelectricity voltage mutual inductor, but photo-electricity mutual-inductor is the application element thereof on high pressure and extra high voltage system at present, in, do not use on the low-pressure system, therefore, qualified to exploit not.The low pressure IT system is injected the method for additional DC source detection of grid insulation resistance, though technology maturation can not be identified fault loop, can not be used for route selection.
Summary of the invention
Realize the system and method for a kind of direct current self-filled type small current earthing wire-selecting of the object of the invention, it is characterized in that its system comprises that direct current signal collecting unit, signal processing and display unit, direct current signal inject unit and power transformer neutral point processing unit automatically.
Be installed in the signals collecting (TA of every road outgoing in the direct current signal collecting unit D), be a cable penetration formula mutual inductor, the annular core that it has two identical band openings of size and the number of turn, the outside winding that direction of winding is identical, two windings also connect, in order to eliminate exchange flux; Make and only keep D.C. magnetic field in the annular core; The iron core opening part is installed Hall element, extracts direct current signal and output voltage signal by external circuit, handles the back by PC again and shows current value and outlet; The outlet threshold value can be set; Because direct current signal has only by singlephase earth fault point and could constitute the loop, so have only (the TA of fault loop D) output of direct current signal just can be arranged.
To through arc suppression coil earthing system, need to increase C 1Stopping direct current, C 1Capacity should cooperate with the inductance value of arc suppression coil, make the capacitive reactance X of electric capacity CLess than 1/10th arc suppression coil inductance induction reactance X LValue is by X LEliminate X CTo the influence of series circuit, for the ability that does not make arc suppression coil compensation ground connection capacitance current obviously reduces C 1Value should be tried one's best greatly, if the compensation ability of arc suppression coil has bigger surplus capacity, the C value can reduce as far as possible.
The present invention cooperates common electromagnetic potential transformer to use.When electrical network generation singlephase earth fault, residual voltage (displacement voltage) appears in the neutral point of a winding of voltage transformer (VT), injects self electrical network by half-wave rectification through fault ground point.Each goes out the top of line loop, and the mutual inductor of a cable penetration formula special construction is installed, and the filtering alternating component is extracted DC component automatically.Because pulsating direct current has only by the trouble spot and could constitute the loop, non-fault loop does not have (or very little) dc current signal.So this method can accurately detect the earth fault loop.
Description of drawings
Fig. 1 is the electrical block diagram of the system and method for a kind of direct current self-filled type small current earthing wire-selecting of the present invention.
Embodiment
As shown in Figure 1, the system and method for a kind of direct current self-filled type small current earthing wire-selecting of the present invention is characterized in that, its system comprises direct current signal collecting unit TA D, signal is handled injects cells D and power transformer neutral point processing unit C automatically with display unit PC, direct current signal 1
Be installed in direct current signal collecting unit TA DIn the signals collecting (TA of every road outgoing D), be a cable penetration formula mutual inductor, the annular core that it has two identical band openings of size and the number of turn, the outside winding that direction of winding is identical, two windings also connect, in order to eliminate exchange flux; Make and only keep D.C. magnetic field in the annular core; The iron core opening part is installed Hall element, extracts direct current signal and output voltage signal by external circuit, handles the back by PC again and shows current value and outlet; The outlet threshold value can be set; Because direct current signal has only by singlephase earth fault point and could constitute the loop, so have only the TA of fault loop DThe output of direct current signal just can be arranged.
To through arc suppression coil earthing system, need to increase C 1Stopping direct current, C 1Capacity should cooperate with the inductance value of arc suppression coil, make the capacitive reactance X of electric capacity CLess than 1/10th arc suppression coil inductance induction reactance X lValue is by X LEliminate X CTo the influence of series circuit, for the ability that does not make arc suppression coil compensation ground connection capacitance current obviously reduces C 1Value should be tried one's best greatly, if the compensation ability of arc suppression coil has bigger surplus capacity, the C value can reduce as far as possible.
The present invention cooperates common electromagnetic potential transformer to use.When electrical network generation singlephase earth fault, residual voltage (displacement voltage) appears in the neutral point of a winding of voltage transformer (VT), injects self electrical network by half-wave rectification through fault ground point.Each goes out the top of line loop, and the mutual inductor of a cable penetration formula special construction is installed, and the filtering alternating component is extracted DC component automatically.Because pulsating direct current has only by the trouble spot and could constitute the loop, non-fault loop does not have (or very little) dc current signal.So this method can accurately detect the earth fault loop.
Embodiment recited above is described preferred implementation of the present invention; be not that scope of the present invention is limited; design under the spiritual prerequisite not breaking away from the present invention; various distortion and improvement that the common engineering technical personnel in this area make technical solution of the present invention all should fall in the definite protection domain of claims of the present invention.

Claims (3)

1. the system and method for a direct current self-filled type small current earthing wire-selecting is characterized in that, its system comprises that direct current signal collecting unit, signal processing and display unit, direct current signal inject unit and power transformer neutral point processing unit automatically.
2. the system and method for a kind of direct current self-filled type small current earthing wire-selecting according to claim 1 is characterized in that, is installed in the signals collecting (TA of every road outgoing in the direct current signal collecting unit D), be a cable penetration formula mutual inductor, the annular core that it has two identical band openings of size and the number of turn, the outside winding that direction of winding is identical, two windings also connect, in order to eliminate exchange flux; Make and only keep D.C. magnetic field in the annular core; The iron core opening part is installed Hall element, extracts direct current signal and output voltage signal by external circuit, handles the back by PC again and shows current value and outlet; The outlet threshold value can be set; Because direct current signal has only by singlephase earth fault point and could constitute the loop, so have only (the TA of fault loop D) output of direct current signal just can be arranged.
3. the system and method for a kind of direct current self-filled type small current earthing wire-selecting according to claim 1 is characterized in that, to through arc suppression coil earthing system, needs to increase C 1Stopping direct current, C 1Capacity should cooperate with the inductance value of arc suppression coil, make the capacitive reactance X of electric capacity CLess than 1/10th arc suppression coil inductance induction reactance X LValue is by X LEliminate X CTo the influence of series circuit, for the ability that does not make arc suppression coil compensation ground connection capacitance current obviously reduces C 1Value should be tried one's best greatly, if the compensation ability of arc suppression coil has bigger surplus capacity, the C value can reduce as far as possible.
CN2013101468673A 2013-04-25 2013-04-25 Direct-current self-injection type small-current grounding and route selecting system and method CN103278737A (en)

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CN2013101468673A CN103278737A (en) 2013-04-25 2013-04-25 Direct-current self-injection type small-current grounding and route selecting system and method

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Cited By (8)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN104133152A (en) * 2014-08-07 2014-11-05 介国安 Direct-current detection device for small-current grounding system in single-phase grounding process
CN105044549A (en) * 2015-04-14 2015-11-11 广西电网有限责任公司电力科学研究院 Direct current grounding searching method with self compensation current
CN105445616A (en) * 2015-11-16 2016-03-30 西安交通大学 Low current grounding and line-selecting system and method based on controlled zero sequence current
CN106684850A (en) * 2016-12-13 2017-05-17 国家电网公司 Grounding system for neutral point in high-voltage transformer
CN106771887A (en) * 2017-03-13 2017-05-31 安徽天电气技术股份有限公司 A kind of instantaneous zero sequence voltage drives ground fault line selection device
CN107340416A (en) * 2017-08-28 2017-11-10 国网江西省电力公司电力科学研究院 A kind of distribution network failure indicator LC tunings are outer to apply signal source
CN108254658A (en) * 2018-04-10 2018-07-06 孟小晶 A kind of distribution earth fault searches instrument and lookup method
CN111398730A (en) * 2020-03-01 2020-07-10 华中科技大学 Power distribution network based on passive injection direct current signal and fault identification method thereof

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JPH08226951A (en) * 1995-01-30 1996-09-03 Nippon Kouatsu Electric Co Power source direction display unit for high-voltage power distribution line
CN101303387A (en) * 2008-04-09 2008-11-12 中国石油化工股份有限公司胜利油田分公司临盘采油厂 Direct current injection type route selecting positioning system and method thereof
LV13922A (en) * 2007-10-16 2009-04-20 Rīgas Tehniskā Universitāte Method for determination of distance to fault place by phase-to-earth fault in distribution networks
CN101435847A (en) * 2008-12-26 2009-05-20 曲娜 Low current grounding DC signal wire selecting method
CN101504436A (en) * 2009-03-03 2009-08-12 济南大学 Semi-wave DC detection method
CN201654160U (en) * 2010-04-07 2010-11-24 北京光耀电力自动化有限公司 Transformer core grounding AC-DC on-line monitoring device
CN202256455U (en) * 2011-10-12 2012-05-30 长沙南车电气设备有限公司 Magnetic balanced type Hall current sensor
CN102508118A (en) * 2011-12-09 2012-06-20 江苏镇安电力设备有限公司 Method for realizing grounding fault line selection of IT (information technology) power system and preparing neutral conductors

Patent Citations (8)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPH08226951A (en) * 1995-01-30 1996-09-03 Nippon Kouatsu Electric Co Power source direction display unit for high-voltage power distribution line
LV13922A (en) * 2007-10-16 2009-04-20 Rīgas Tehniskā Universitāte Method for determination of distance to fault place by phase-to-earth fault in distribution networks
CN101303387A (en) * 2008-04-09 2008-11-12 中国石油化工股份有限公司胜利油田分公司临盘采油厂 Direct current injection type route selecting positioning system and method thereof
CN101435847A (en) * 2008-12-26 2009-05-20 曲娜 Low current grounding DC signal wire selecting method
CN101504436A (en) * 2009-03-03 2009-08-12 济南大学 Semi-wave DC detection method
CN201654160U (en) * 2010-04-07 2010-11-24 北京光耀电力自动化有限公司 Transformer core grounding AC-DC on-line monitoring device
CN202256455U (en) * 2011-10-12 2012-05-30 长沙南车电气设备有限公司 Magnetic balanced type Hall current sensor
CN102508118A (en) * 2011-12-09 2012-06-20 江苏镇安电力设备有限公司 Method for realizing grounding fault line selection of IT (information technology) power system and preparing neutral conductors

Cited By (12)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN104133152A (en) * 2014-08-07 2014-11-05 介国安 Direct-current detection device for small-current grounding system in single-phase grounding process
CN104133152B (en) * 2014-08-07 2018-01-12 介国安 DC detecting device during single-phase earthing of small current earthing system
CN105044549A (en) * 2015-04-14 2015-11-11 广西电网有限责任公司电力科学研究院 Direct current grounding searching method with self compensation current
CN105044549B (en) * 2015-04-14 2018-04-20 广西电网有限责任公司电力科学研究院 A kind of direct current grounding trouble shooting method with self compensation electric current
CN105445616A (en) * 2015-11-16 2016-03-30 西安交通大学 Low current grounding and line-selecting system and method based on controlled zero sequence current
CN105445616B (en) * 2015-11-16 2018-08-07 西安交通大学 A kind of Little Current Ground Connection System and method based on controlled zero-sequence current
CN106684850B (en) * 2016-12-13 2019-08-13 国家电网公司 High-tension transformer earth neutral system
CN106684850A (en) * 2016-12-13 2017-05-17 国家电网公司 Grounding system for neutral point in high-voltage transformer
CN106771887A (en) * 2017-03-13 2017-05-31 安徽天电气技术股份有限公司 A kind of instantaneous zero sequence voltage drives ground fault line selection device
CN107340416A (en) * 2017-08-28 2017-11-10 国网江西省电力公司电力科学研究院 A kind of distribution network failure indicator LC tunings are outer to apply signal source
CN108254658A (en) * 2018-04-10 2018-07-06 孟小晶 A kind of distribution earth fault searches instrument and lookup method
CN111398730A (en) * 2020-03-01 2020-07-10 华中科技大学 Power distribution network based on passive injection direct current signal and fault identification method thereof

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Application publication date: 20130904