CN106950441A - A kind of sensor for on-line checking transformer DC magnetic bias - Google Patents

A kind of sensor for on-line checking transformer DC magnetic bias Download PDF

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Publication number
CN106950441A
CN106950441A CN201710081811.2A CN201710081811A CN106950441A CN 106950441 A CN106950441 A CN 106950441A CN 201710081811 A CN201710081811 A CN 201710081811A CN 106950441 A CN106950441 A CN 106950441A
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CN
China
Prior art keywords
magnetic
excitation
transformer
sensor
coil
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CN201710081811.2A
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Chinese (zh)
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CN106950441B (en
Inventor
曹建安
刘懿莹
拉菲格·汗
虞珂
张维
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西安交通大学
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    • GPHYSICS
    • G01MEASURING; TESTING
    • G01RMEASURING ELECTRIC VARIABLES; MEASURING MAGNETIC VARIABLES
    • G01R31/00Arrangements for testing electric properties; Arrangements for locating electric faults; Arrangements for electrical testing characterised by what is being tested not provided for elsewhere

Abstract

The invention discloses a kind of sensor for on-line checking transformer DC magnetic bias, including U-shaped special-shaped magnetic core, excitation coil and detection coil are wound with respectively on U-shaped special-shaped magnetic core, and detection coil is wound in outside excitation coil, and excitation coil is connected with excitation current source.The sensor combines Fluxgate Technique and devises a special-shaped magnetic core.After inside transformer magnetic field imports sensor, D.C. magnetic field is detected using Fluxgate Technique, detection coil sensing obtains voltage, and isolated DC component then can obtain inside transformer direct current flux, judge whether transformer occurs magnetic biasing by the monitoring to direct current flux.

Description

A kind of sensor for on-line checking transformer DC magnetic bias
【Technical field】
The invention belongs to power transformer and sensor field, it is related to a kind of for on-line checking transformer DC magnetic bias Sensor.
【Background technology】
When power transformer works, iron core is in remagnetization state and non DC bias phenomenon.But in static reacance During power back-off and high voltage direct current converter, Transformer Winding compole is also easy to produce DC component, so as to cause transformer Magnetic core magnetization center of curve point shifts, i.e. DC magnetic bias phenomena.Now the waveform Severe distortion of exciting current, harmonic wave are a large amount of Produce, noise is significantly increased, transformer is overheated, and directly affects the normal work of transformer, or even cause transformer to burn.Cause This, the D.C. magnetic biasing of detection transformer core is to ensure the important measures of transformer health operation.
At present, D.C. magnetic biasing detection can use electrical measuring method, i.e.,:Electric current is used at transformer neutral point ground outlet Transformer sampled signal, directly determines whether D.C. magnetic biasing by detecting at neutral point DC current.But this method is not The magnetic bias of single-phase transformer can be detected, and when suppressing D.C. magnetic biasing using low resistance grounding method, nearby stations can be made Transformer neutral point direct current increases, and now electrical measuring method can not help operating personnel to make accurate judgement, therefore electrical measuring method is accurate Property is not high, and uses limitation.
In addition, D.C. magnetic biasing detection can also use vibration and noise sensor, extract noise during transformer work And vibration signal waveforms, contrast, determined whether with this with the transformer noise under non DC bias and vibration signal waveforms The generation of D.C. magnetic biasing.But the working condition of transformer is influenceed by factors such as power, environment temperature and service lives.When right When there is deviation than noise and rumble spectrum, it is difficult to judgment bias be as D.C. magnetic biasing cause or the factor such as temperature caused by.
【The content of the invention】
It is an object of the invention to overcome the shortcoming of above-mentioned prior art there is provided one kind to be used for on-line checking transformer dc Whether the sensor of magnetic bias, the sensor occurs D.C. magnetic biasing when can detect transformer work, by detecting the straight of transformer Flow magnetic flux to detect magnetic bias, with higher sensitivity, and on-line measurement can be realized.
To reach above-mentioned purpose, the present invention is achieved using following technical scheme:
On a kind of sensor for on-line checking transformer DC magnetic bias, including U-shaped special-shaped magnetic core, U-shaped special-shaped magnetic core Excitation coil and detection coil are wound with respectively, detection coil is wound in outside excitation coil, excitation coil and excitation current source It is connected.
The present invention is further improved:
U-shaped special-shaped magnetic core is formed by stacking by multilayer cobalt-based band, and is provided with the middle part of U-shaped magnetic core through hole, through hole or so two Side is coil-wound parts;Excitation current source is used to produce the cycle in the excitation coil that winding is connected in the magnetic core through hole left and right sides Property change, identical, the in opposite direction excitation field of size.
Excitation coil, which is connected, is wound in the magnetic core of the through hole left and right sides.
The winding direction of excitation coil ensures that when there is exciting current to flow through excitation coil through hole surrounding can form closure Toroidal magnetic field.
The coil turn that excitation coil is wound in through hole both sides magnetic core is equal.
Insulation processing is used between detection coil and excitation coil.
Compared with prior art, the invention has the advantages that:
The present invention proposes the on-line checking of transformer iron core magnetic bias will be realized, using Fluxgate Technique to judge transformer Whether magnetic bias state is operated in.Fluxgate Technique has the advantages that sensitivity is high, by its magnetic circuit phase with electrical transformer cores With reference to.The present invention applies to fluxgate sensor principle in transformer bias detection, by observing DC current in circuit Change to reflect the working condition of transformer.When transformer normal work occurs without magnetic biasing phenomenon, sensor is put into and measured, prison Slowdown monitoring circuit will show no current DC component.When magnetic biasing occurs for transformer, observation circuit will be observed that current dc component increases Plus phenomenon.The voltage device over-heat inside as caused by voltage device magnetic bias, noise can be effectively prevented to become big, energy transfer efficiency reduction The problems such as, improve transformer operating efficiency and security performance.
【Brief description of the drawings】
Fig. 1 is the operating diagram of magnetic core of transformer alternating current-direct current magnetic flux on-line checking novel sensor of the present invention.
Fig. 2 is the design drawing and pictorial diagram of magnetic core of transformer alternating current-direct current magnetic flux on-line checking novel sensor of the present invention.
Fig. 3 is exciting current in the excitation coil of magnetic core of transformer alternating current-direct current magnetic flux on-line checking novel sensor of the present invention Oscillogram.
Wherein:1-U types abnormal shape magnetic core;2- excitation coils;3- excitation current sources;4- detection coils.
【Embodiment】
The present invention is described in further detail below in conjunction with the accompanying drawings:
Referring to Fig. 1-3, the present invention combines fluxgate sensor relative theory, it is proposed that one kind is used for on-line checking transformer The sensor of D.C. magnetic biasing, and the engine request of on-line checking can be realized.The present invention includes U-shaped special-shaped magnetic core 1, U-shaped abnormal shape Excitation coil 2 and detection coil 4 are wound with magnetic core 1 respectively, detection coil 4 is wound in outside excitation coil 3, excitation coil 2 It is connected with excitation current source 3.In order to prevent from being vortexed the loss caused, U-shaped special-shaped magnetic core 1 is formed by stacking by multilayer cobalt-based band, And through hole is provided with the middle part of U-shaped magnetic core, the through hole left and right sides is coil-wound parts.It is left that the series connection of excitation coil 2 is wound in through hole The magnetic core of right both sides, winding direction need to ensure that, when there is exciting current to flow through excitation coil 2, through hole surrounding can form close ring Shape magnetic field, and it is equal to be wound in the coil turn of through hole both sides iron core.
Excitation current source 3 of the present invention is used to produce the cycle in the excitation coil 2 that winding is connected in the magnetic core through hole left and right sides Property change, identical, the in opposite direction excitation field of size.Exciting current is the certain pulse of frequency, when exciting current is reached During peak value, correspondence magnetic core internal magnetic field is up to maximum, and now sensor magnetic core reaches saturation state.
Detection coil 4 is wound in outside excitation coil 3, and needs insulation processing between excitation coil 3.Working sensor When, according to Faraday's electromagnetic induction law, the coil will induce electromotive force.Extracted using FFT or integral transformation in circuit Voltage DC component is detectable direct current flux.
The present invention is simple in construction, can monitor inside transformer working condition by examining direct current flux, improve transformer Operating efficiency and security performance.
As shown in figure 1, the present invention is made up of U-shaped special-shaped magnetic core 1, excitation coil 2, excitation current source 3 and measuring coil 4. The excitation coil series connection of two equal turn numbers is wound in the magnetic core of the through hole left and right sides, when there is exciting current to pass through, through hole four Week can form closed annular magnetic field.The magnetic field that the excitation field and transformer introduce sensor is overlapped mutually so that sensor Reach saturation state.
Inside transformer magnetic field to be measured is divided into D.C. magnetic field and AC magnetic field, when sensor is accessed into transformer to be measured, Because sensor magnetic permeability is far above transformer, magnetic field is by flow sensor in transformer, if the friendship of flow sensor Flow component and DC component be divided into and.
Fig. 2 is U-shaped special-shaped Magnetic Core Design figure and processing pictorial diagram, and silicon steel sheet uses cobalt-based material, is induction coil, and Respectively magnet exciting coil, and the two number of turn is identical.
As shown in figure 3, in the presence of exciting current, week is produced in the coil and coil of the series connection winding of the groove left and right sides Identical, the in opposite direction excitation field of the change of phase property, size.Exciting current is the certain pulse of frequency, when exciting current is reached When maximum, the magnetic field in correspondence magnetic core also reaches that maximum, i.e. sensor reach saturation state.The excitation field is enabled to The toroidal magnetic field of change is formed in sensor monolithic magnetic core.According to Faraday's electromagnetic induction law, now measuring coil will be felt Electromotive force should be gone out.In both comprising the voltage that is induced by AC magnetic field, and the DC voltage induced comprising D.C. magnetic field.
Fast Fourier Transform (FFT) is carried out to gained induced electromotive force or Integral Processing eliminates AC compounent, you can by direct current Component extraction goes out.When magnetic biasing occurs for transformer to be measured, substantially conversion will occur for DC component, you can by monitoring DC component To judge whether transformer occurs magnetic bias.
The technological thought of above content only to illustrate the invention, it is impossible to which protection scope of the present invention is limited with this, it is every to press According to technological thought proposed by the present invention, any change done on the basis of technical scheme each falls within claims of the present invention Protection domain within.

Claims (6)

1. a kind of sensor for on-line checking transformer DC magnetic bias, it is characterised in that including U-shaped special-shaped magnetic core (1), U Excitation coil (2) and detection coil (4) are wound with respectively on type abnormal shape magnetic core (1), and detection coil (4) is wound in excitation coil (3) outside, excitation coil (2) is connected with excitation current source (3).
2. the sensor according to claim 1 for on-line checking transformer DC magnetic bias, it is characterised in that U-shaped different Type magnetic core (1) is formed by stacking by multilayer cobalt-based band, and is provided with through hole in the middle part of U-shaped magnetic core, and the through hole left and right sides twines for coil Around part;Excitation current source (3) is used in the excitation coil (2) of magnetic core through hole left and right sides series connection winding produce periodically change Identical, the in opposite direction excitation field of change, size.
3. the sensor according to claim 2 for on-line checking transformer DC magnetic bias, it is characterised in that excitation line Circle (2) series connection is wound in the magnetic core of the through hole left and right sides.
4. the sensor according to claim 3 for on-line checking transformer DC magnetic bias, it is characterised in that excitation line The winding direction for enclosing (2) ensures that when there is exciting current to flow through excitation coil (2) through hole surrounding can form closed annular magnetic .
5. the sensor according to claim 4 for on-line checking transformer DC magnetic bias, it is characterised in that excitation line The coil turn that circle (2) is wound in through hole both sides magnetic core is equal.
6. the sensor according to claim 1 for on-line checking transformer DC magnetic bias, it is characterised in that detection line Enclose and insulation processing is used between (4) and excitation coil (3).
CN201710081811.2A 2017-02-15 2017-02-15 A kind of sensor for on-line checking transformer DC magnetic bias Active CN106950441B (en)

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Cited By (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN109358300A (en) * 2018-09-29 2019-02-19 河南理工大学 A kind of micro fluxgate sensor based on stereochemical structure iron core
CN110389250A (en) * 2019-07-29 2019-10-29 武汉新电电气股份有限公司 A kind of device and method of for transformer D.C. magnetic biasing event early warning

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SU971618A1 (en) * 1981-05-25 1982-11-07 Курский Политехнический Институт Device for sensing contact of tool with workpiece
CN1052302C (en) * 1993-12-29 2000-05-10 住友特殊金属株式会社 DC current sensor
CN201429587Y (en) * 2009-06-19 2010-03-24 长安大学 Novel sensor for steel rail detection
CN203204135U (en) * 2013-03-28 2013-09-18 中国船舶重工集团公司第七一〇研究所 U type single magnetic core magnetic flux gate probe
CN104614690A (en) * 2014-12-18 2015-05-13 哈尔滨理工大学 Micro-array type fluxgate sensor
CN105137370A (en) * 2015-08-27 2015-12-09 无锡伊佩克科技有限公司 Low power consumption miniature fluxgate sensor
CN105866239A (en) * 2016-04-25 2016-08-17 江南大学 Detection method for U-shaped pulse fusing sensor based on ferromagnetic test piece

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* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
SU971618A1 (en) * 1981-05-25 1982-11-07 Курский Политехнический Институт Device for sensing contact of tool with workpiece
CN1052302C (en) * 1993-12-29 2000-05-10 住友特殊金属株式会社 DC current sensor
CN201429587Y (en) * 2009-06-19 2010-03-24 长安大学 Novel sensor for steel rail detection
CN203204135U (en) * 2013-03-28 2013-09-18 中国船舶重工集团公司第七一〇研究所 U type single magnetic core magnetic flux gate probe
CN104614690A (en) * 2014-12-18 2015-05-13 哈尔滨理工大学 Micro-array type fluxgate sensor
CN105137370A (en) * 2015-08-27 2015-12-09 无锡伊佩克科技有限公司 Low power consumption miniature fluxgate sensor
CN105866239A (en) * 2016-04-25 2016-08-17 江南大学 Detection method for U-shaped pulse fusing sensor based on ferromagnetic test piece

Cited By (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN109358300A (en) * 2018-09-29 2019-02-19 河南理工大学 A kind of micro fluxgate sensor based on stereochemical structure iron core
CN109358300B (en) * 2018-09-29 2021-02-05 河南理工大学 Miniature fluxgate sensor based on spatial structure iron core
CN110389250A (en) * 2019-07-29 2019-10-29 武汉新电电气股份有限公司 A kind of device and method of for transformer D.C. magnetic biasing event early warning

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