CN102749595B - Method for measuring residual magnetic induction density of iron core of transformer - Google Patents
Method for measuring residual magnetic induction density of iron core of transformer Download PDFInfo
- Publication number
- CN102749595B CN102749595B CN201210235575.2A CN201210235575A CN102749595B CN 102749595 B CN102749595 B CN 102749595B CN 201210235575 A CN201210235575 A CN 201210235575A CN 102749595 B CN102749595 B CN 102749595B
- Authority
- CN
- China
- Prior art keywords
- transformer
- value
- current
- residual magnetic
- measuring
- 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.)
- Active
Links
Landscapes
- Measuring Magnetic Variables (AREA)
Abstract
The invention relates to a method for measuring the residual magnetic induction density of an iron core of a transformer. The method comprises the following steps of: step one, applying a current source at the high-voltage side of the transformer, increasing the current by one value, and measuring current and voltage waveforms of a point; step two, determining the number of points needing to record a voltage waveform and the increase amplitude of current; step three, according to the determined current increase amplitude, gradually increasing a value of current injected into the transformer, recording current and voltage values of the point to be needed so as to reduce the input current value to be zero, and switching off the current source; and step four, inputting the measured data by utilizing an optimization algorithm to identify the B-value formula of the transformer, and further inversely guiding out a B-value when the time that t is equal to 0. The method for measuring the residual magnetic induction density of the iron core of the transformer has the beneficial effects that the method can be widely applied to verification of the demagnetization effect after a demagnetization device is used for demagnetizing and has very important significance in a safe and stable operation of the transformer.
Description
Technical field
The present invention relates to a kind of measuring method of transformer core residual magnetic flux density, be applicable in electrical network after Repair of Transformer, the detection of its residual magnetic flux density amount before air-drop, belongs to the operation maintenance field of converting equipment.
Background technology
Along with the fast development of China's industrial economy, to electricity needs rapid growth, the requirement of the reliable supply of electric power also increases day by day.Power transformer is one of critical elements forming in electrical network, in the safe and reliable power supply of electrical network, has extremely important effect.Yet there are a lot of air-drop transformers and cause transformer tripping operation and chromatogram to occur abnormal case in recent domestic, affects the reliability of mains supply, causes huge economic loss and bad social benefit.
Hysteresis in ferrimagnet by extensively cognitive.When externally-applied magnetic field puts on ferromagnetic material, the dipole of its atom is arranged voluntarily according to impressed field.Even when impressed field is withdrawn, part is arranged and is still kept, if when now magnetic field linearity is reduced to 0 field intensity, now magnetic induction density B can not be down to 0, now B value becomes remanent magnetism.
The magnetization curve of the ferromagnetic material of transformer and magnetic hysteresis loop are the key properties of this material; the iron core residual magnetic flux density of transformer; transformer is had to many-sided impact; when transformer throwing people moves, iron core residual magnetic flux density makes transformer core saturated; in exciting current, produce a large amount of harmonic waves; this has not only increased the reactive power consumption of transformer, and may cause protective relaying device misoperation, and the case of transformer tripping at home and abroad all occurred repeatedly because of transformer remanent magnetism, to cause.In addition, the height of iron core is saturated increases leakage field, causes that hardware and fuel tank are overheated, and local overheating will make insulating paper aging and transformer oil is decomposed, and affect the life-span of transformer.In recent years, there are a lot of air-drop transformers both at home and abroad tripping operation and the abnormal situation of chromatographic data had occurred, former because iron core remanent magnetism causes.Therefore, transformer core remanent magnetism problem has caused attention both domestic and external.
Use the method for demagnetization have direct current and exchange two kinds of methods both at home and abroad, data shows, no matter adopt which kind of demagnetizing method, all can not guarantee the remanent magnetism of eliminating transformer iron core completely that just once demagnetizes, so in engineering application need various demagnetization effectivenesses to verify, but lacking at present effective means tests to transformer degaussing effect, to after transformer core demagnetization, cannot determine its iron core residual magnetic flux density amount, therefore find a kind of measuring method of transformer core residual magnetic flux density, reach examination erasure effect, and then the safe and stable operation that guarantees transformer seems and is necessary very much.
Summary of the invention
The present invention measures difficult problem for transformer core residual magnetic flux density, a kind of measuring method of iron core residual magnetic flux density has been proposed, the method can be overhauled front and back by measuring transformer, the residual magnetic flux density of its iron core, also after check utilizes demagnetizing apparatus to demagnetize to transformer simultaneously, whether its demagnetization effectiveness reaches demagnetization requirement, thereby while avoiding dropping transformer, the infringement that equipment is produced.
Juche idea of the present invention is on transformer, to pass into an ac current source, because core field intensity H and exciting current i
0linear, therefore by exciting current i
0can calculate magnetic field intensity H; In like manner, magnetic induction density B can be calculated and be obtained by induction electromotive force e, when passing into simple sinusoidal alternating current, induction electromotive force e be can be by multiple harmonic polynomial repressentation, therefore can be by spectrum analysis, and then the each harmonic content of definite induction electromotive force e, determine the polynomial expression of matching e, with this, determine the polynomial fitting of matching B; Therefore finally utilize the matching of optimized algorithm to transformer original state lower core residual magnetic flux density, can measure that finally to solve at electric current be at 0 o'clock, the size of iron core residual magnetic flux density amount B, determines the residual magnetic flux density amount of iron core with this.
Technical scheme, applies simple sinusoidal alternating current source in the high-pressure side of transformer, and application oscillograph gathers the electric current of high-pressure side injection and the voltage signal at two ends thereof; A winding is injected to the current value needing, do a pause, utilize electric current and the voltage waveform of this point of oscillograph recording, after having recorded at first, can utilize spectrum analysis technique to carry out spectrum analysis to gathered voltage waveform, the content of each harmonic in analytical voltage waveform, according to analysis result, determine the exponent number of the polynomial fitting of residual magnetic flux density B, according to the exponent number of polynomial fitting, determine the number of the unknown number in polynomial fitting, and determine the quantity of the voltage waveform that needs record with this; According to counting of required measuring voltage waveform, determine and inject the amplitude that once winding current increases, the current value that progressively increases a winding of injection transformer with fixed amplitude, when rising to the current value needing at every turn, record current voltage waveform, by that analogy, recorded after the electric current and magnitude of voltage of all needs points, can reduce input current value to 0, then turn-off current source; Finally, utilize optimized algorithm, according to the data of measurement point, the polynomial fitting of fixed B is carried out to matching, and then instead release when t=0 the value of iron core residual magnetic flux density amount B.
Implementation step of the present invention is as follows:
The first step, applies current source at high voltage side of transformer, and electric current is risen to a value, measures the current-voltage waveform of this point;
Second step, pass through spectrum analyzer, the harmonic content of analytical voltage waveform, according to analysis result, determine the polynomial fitting exponent number of residual magnetic flux density B, according to the polynomial fitting exponent number of B, determine the number of unknown number in polynomial fitting, with this, determine and need counting and the increasing degree of electric current of recording voltage waveform;
The 3rd step, according to definite electric current increasing degree, progressively increases the current value of injection transformer, has recorded after the electric current and magnitude of voltage of all needs points, can reduce input current value to 0, then turn-off current source;
The 4th step, utilizes optimized algorithm, brings the data of having measured into, and the B value formula of transformer is carried out to identification, and further anti-release is in t=0 B value constantly.
Second step of the present invention determines that the method for the polynomial fitting exponent number of B is:
Passing into exciting current i
0in the situation of sinusoidal quantity, alternating magnetic field intensity H can represent: H=H
msin ω t; Now B can be expressed as:
Again because
so can determine matching residual magnetic flux density B exponent number according to the spectrum analysis of test voltage wave, for carrying out the 3rd step and the 4th step is determined foundation.
The 4th step of the present invention determines that the method for calculating B value is:
Because
so can be according to the induction electromotive force e measuring, the value of B while obtaining different measuring point.According to the polynomial fitting of the determined B value of second step, utilize optimized algorithm to carry out identification to formula (1), pick out B
0, B
1, B
2, B
3... and
equivalence, this group parameter identification out after, can instead release t=0 constantly time, the value of magnetic induction density B, further derives the residual magnetic flux density amount of iron core.
The invention has the beneficial effects as follows, solved the immesurable problem of transformer core residual magnetic flux density, utilize optimized algorithm and the anti-method that pushes away of mathematics to measure iron core residual magnetic flux density, can be widely used in its degaussing validity check after the degaussing of degaussing equipment, transformer safe and stable operation tool is of great significance.
Accompanying drawing explanation
Fig. 1 is measuring principle figure of the present invention;
Fig. 2 is the process flow diagram of described method of the present invention.
Number in the figure is: 1. ac current source; 2. oscillograph; 3. current probe; 4. voltage probe; 5. transformer.
Embodiment
Implementation step of the present invention is as follows:
The first step, applies current source at high voltage side of transformer, and electric current is risen to a value, measures the current-voltage waveform of this point;
Second step, pass through spectrum analyzer, the harmonic content of analytical voltage waveform, according to analysis result, determine the polynomial fitting exponent number of residual magnetic flux density B, according to the polynomial fitting exponent number of B, determine the number of unknown number in polynomial fitting, with this, determine and need counting and the increasing degree of electric current of recording voltage waveform;
The 3rd step, according to definite electric current increasing degree, progressively increases the current value of injection transformer, has recorded after the electric current and magnitude of voltage of all needs points, can reduce input current value to 0, then turn-off current source
The 4th step, utilizes optimized algorithm, brings the data of having measured into, and the B value formula of transformer is carried out to identification, and further anti-release is in t=0 B value constantly.
Second step of the present invention determines that the method for the polynomial fitting exponent number of B is:
Passing into exciting current i
0in the situation of sinusoidal quantity, alternating magnetic field intensity H can represent: H=H
msin ω t; Now B can be expressed as:
Again because
so can determine matching residual magnetic flux density B exponent number according to the spectrum analysis of test voltage wave, for carrying out the 3rd step and the 4th step is determined foundation.
The 4th step of the present invention determines that the method for calculating B value is:
Because
so can be according to the induction electromotive force e measuring, the value of B while obtaining different measuring point.According to the polynomial fitting of the determined B value of second step, utilize optimized algorithm to carry out identification to formula (1), pick out B
0, B
1, B
2, B
3... and
equivalence, this group parameter identification out after, can instead release t=0 constantly time, the value of magnetic induction density B, further derives the residual magnetic flux density amount of iron core.
As shown in Figure 1 and Figure 2, a winding at transformer passes into an ac current source, and current probe is installed simultaneously in loop, at winding two ends, voltage probe is installed, by probe, current and voltage signals is accessed to oscillograph, with this, measure the current-voltage waveform in winding one time.
Its principle of work is under ac magnetization condition, and B and H are the very complicated periodic functions of time t, and it is different that power supply is output as the numerical value of sinusoidal B and sinusoidal H, and waveform is also completely different.
When passing into ac current source, exciting current i
0for sinusoidal quantity, because H and i
0linear, so alternating magnetic field intensity H can represent: H=H
msin ω t, and magnetic induction density B is the complicated function of time, but B (t) is still the periodic function of time t, can be according to Fu Shi functional expansion therefore:
In formula: B
1, B
2, B
3... represent respectively fundametal compoment, second harmonic component, third-harmonic component and other higher harmonic components.Because
i in formula
0: exciting current, l: the average length of magnetic path; E: induction electromotive force; S: the cross-sectional area of sample; N
1: magnetization umber of turn.So, can be by the current i of measuring circuit
0reflect respectively magnetic field intensity H and magnetic induction density B with induction electromotive force e.
The process flow diagram of the method as shown in Figure 2, first, according to the situation of tested transformer, applies current source at high voltage side of transformer, and electric current is risen to a value, measures the current-voltage waveform of this point; Pass through spectrum analyzer, the harmonic content of analytical voltage waveform, according to analysis result, determine the polynomial fitting exponent number of residual magnetic flux density B, according to the polynomial fitting exponent number of B, determine the number of unknown number in polynomial fitting, with this, determine and need counting and the increasing degree of electric current of recording voltage waveform; According to definite electric current increasing degree, progressively increase the current value of injection transformer, recorded after the electric current and magnitude of voltage of all needs points, can reduce input current value to 0, then turn-off current source; For the voltage e having surveyed, can calculate B (t) value, utilize optimized algorithm to carry out identification to formula (1), pick out B
0, B
1, B
2, B
3... and
equivalence, this group parameter identification out after, can instead release t=0 constantly time, the value of magnetic induction density B, further derives the residual magnetic flux density amount of iron core.
Claims (3)
1. a measuring method for transformer core residual magnetic flux density, is characterized in that, described measuring method comprises the steps:
The first step, applies current source at high voltage side of transformer, and electric current is risen to a value, measures the current-voltage waveform of this point;
Second step, by spectrum analyzer, the harmonic content of analytical voltage waveform, according to analysis result, determine the polynomial expression exponent number of magnetic induction density B, according to the polynomial expression exponent number of B, the number of unknown number in certain polynomial, determines and needs counting and the increasing degree of electric current of recording voltage waveform with this;
The 3rd step, according to definite electric current increasing degree, progressively increases the current value of injection transformer, has recorded after the electric current and magnitude of voltage of all needs points, can reduce input current value to 0, then turn-off current source;
The 4th step, utilizes optimized algorithm, brings the data of having measured into, and the B value formula of transformer is carried out to identification, and further anti-release is in t=0 B value constantly.
2. the measuring method of a kind of transformer core residual magnetic flux density as claimed in claim 1, is characterized in that, described second step determines that the method for the polynomial fitting exponent number of B is:
Passing into exciting current i
0in the situation of sinusoidal quantity, alternating magnetic field intensity H can represent: H=H
msin ω t; Now B can be expressed as:
Again because
so can determine matching magnetic induction density B exponent number according to the spectrum analysis of test voltage wave, for carrying out the 3rd step and the 4th step is determined foundation.
3. the measuring method of a kind of transformer core residual magnetic flux density as claimed in claim 1, is characterized in that, the 4th described step determines that the method for calculating B value is:
Because
so can be according to the induction electromotive force e measuring, the value of B while obtaining different measuring point.According to the polynomial fitting of the determined B value of second step, utilize optimized algorithm to carry out identification to formula (1), pick out B
0, B
1, B
2, B
3... and
equivalence, this group parameter identification out after, can instead release t=0 constantly time, the value of magnetic induction density B, further derives the residual magnetic flux density amount of iron core.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201210235575.2A CN102749595B (en) | 2012-07-09 | 2012-07-09 | Method for measuring residual magnetic induction density of iron core of transformer |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201210235575.2A CN102749595B (en) | 2012-07-09 | 2012-07-09 | Method for measuring residual magnetic induction density of iron core of transformer |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| CN102749595A CN102749595A (en) | 2012-10-24 |
| CN102749595B true CN102749595B (en) | 2014-11-26 |
Family
ID=47029944
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN201210235575.2A Active CN102749595B (en) | 2012-07-09 | 2012-07-09 | Method for measuring residual magnetic induction density of iron core of transformer |
Country Status (1)
| Country | Link |
|---|---|
| CN (1) | CN102749595B (en) |
Families Citing this family (6)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN103105594B (en) * | 2013-01-24 | 2014-07-16 | 江苏省电力公司电力科学研究院 | Current mutual inductor residual magnetism detection method based on small-signal gradient mapping |
| CN103675728B (en) * | 2013-11-22 | 2016-01-06 | 河北工业大学 | The measuring method of closed magnetic path magnetic core remanent magnetism |
| CN104749537A (en) * | 2015-04-20 | 2015-07-01 | 国家电网公司 | Hysteresis loop measuring method of current transformer |
| CN104833928B (en) * | 2015-04-30 | 2017-09-29 | 国网四川省电力公司电力科学研究院 | A kind of large-scale power transformer remanent magnetism detection method |
| CN105182261B (en) * | 2015-11-02 | 2018-06-22 | 乐晓蓉 | Coil inside core field intensity contactless measurement |
| CN114688962B (en) * | 2022-03-24 | 2023-01-06 | 湖南大学 | System and method for measuring magnetostrictive strain of rare earth giant magnetostrictive material |
Citations (5)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPH09251064A (en) * | 1996-03-15 | 1997-09-22 | Nippon Signal Co Ltd:The | Magnetic sensor and object detector, and object recognition device |
| JPH11162769A (en) * | 1997-12-01 | 1999-06-18 | Hitachi Ltd | Apparatus and method for evaluating dc polarization of transformer |
| CN1283797A (en) * | 2000-09-18 | 2001-02-14 | 东南大学 | Method and device for measuring magnetic hysteresis loop |
| JP2006284261A (en) * | 2005-03-31 | 2006-10-19 | Mitsubishi Electric Corp | Residual magnetic flux measuring instrument |
| CN101980306A (en) * | 2010-10-15 | 2011-02-23 | 南京中钞长城金融设备有限公司 | Method and tester for detecting magnetic characteristic of coin |
-
2012
- 2012-07-09 CN CN201210235575.2A patent/CN102749595B/en active Active
Patent Citations (5)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPH09251064A (en) * | 1996-03-15 | 1997-09-22 | Nippon Signal Co Ltd:The | Magnetic sensor and object detector, and object recognition device |
| JPH11162769A (en) * | 1997-12-01 | 1999-06-18 | Hitachi Ltd | Apparatus and method for evaluating dc polarization of transformer |
| CN1283797A (en) * | 2000-09-18 | 2001-02-14 | 东南大学 | Method and device for measuring magnetic hysteresis loop |
| JP2006284261A (en) * | 2005-03-31 | 2006-10-19 | Mitsubishi Electric Corp | Residual magnetic flux measuring instrument |
| CN101980306A (en) * | 2010-10-15 | 2011-02-23 | 南京中钞长城金融设备有限公司 | Method and tester for detecting magnetic characteristic of coin |
Non-Patent Citations (6)
| Title |
|---|
| 吴丽珠等.用示波器测量铁磁物质的磁滞回线.《韶关学院学报·自然学报》.2006,第27卷(第9期), * |
| 用示波器测量铁磁物质的磁滞回线;吴丽珠等;《韶关学院学报·自然学报》;20060930;第27卷(第9期);全文 * |
| 电力变压器铁心剩磁检测方法研究;陈文臣等;《陕西电力》;20091031(第10期);全文 * |
| 计及剩磁的变压器励磁涌流的仿真研究;黄金等;《变压器》;20091130;第46卷(第11期);全文 * |
| 陈文臣等.电力变压器铁心剩磁检测方法研究.《陕西电力》.2009,(第10期), * |
| 黄金等.计及剩磁的变压器励磁涌流的仿真研究.《变压器》.2009,第46卷(第11期), * |
Also Published As
| Publication number | Publication date |
|---|---|
| CN102749595A (en) | 2012-10-24 |
Similar Documents
| Publication | Publication Date | Title |
|---|---|---|
| CN102749595B (en) | Method for measuring residual magnetic induction density of iron core of transformer | |
| CN103913710A (en) | Method for measuring residual magnetic flux density of iron core of transformer | |
| CN103105594B (en) | Current mutual inductor residual magnetism detection method based on small-signal gradient mapping | |
| CN104833928B (en) | A kind of large-scale power transformer remanent magnetism detection method | |
| CN103207379B (en) | Method and device for measuring direct current magnetic bias error characteristics of current transformer | |
| CN102435903B (en) | Online monitoring device for turn-to-turn short circuit of voltage transformer | |
| CN106772152B (en) | A kind of measurement method of transformer core remanent magnetism | |
| CN105425175A (en) | Iron core remanent magnetism elimination and measurement method based on polarity-reversal DC voltage source | |
| CN103176148A (en) | Testing device and testing method for silicon steel core limit hysteresis loop | |
| Schöttke et al. | Transfer characteristic of a MV/LV transformer in the frequency range between 2 kHz and 150 kHz | |
| CN111965569B (en) | DC magnetic bias level measurement method, device and system for online operation transformer | |
| Fritsch et al. | Saturation of high-frequency current transformers: Challenges and solutions | |
| CN203287514U (en) | Current transformer DC magnetic bias error characteristic measuring device | |
| CN104833929A (en) | Transformer demagnetization analyzer | |
| CN203117408U (en) | Testing device of silicon steel iron core ultimate hysteresis loop | |
| Wang et al. | Research on characteristics of a high precision current sensor | |
| CN202383224U (en) | Online monitoring apparatus for turn-to-turn short circuit of voltage transformer | |
| Huo et al. | A Review of Research Progress on Residual Magnetism Detection Methods for Power Transformer Cores | |
| CN204556807U (en) | A kind of transformer demagnetization analyzer | |
| Hein et al. | Comparative core loss calculation methods for magnetic materials under harmonics effect | |
| Li et al. | Research and application of calibration and comparison system for partial discharge live detection equipment | |
| CN106226578A (en) | A kind of large direct current measuring method based on magnetic amplifier principle | |
| CN203672950U (en) | Detection device for current of secondary circuit caused by isolating switch operation | |
| CN110646754A (en) | Frequency response-based transformer residual magnetism detection method and system | |
| CN104931913A (en) | Method for detecting additional dynamic component of Rogowski coil electronic current transformer |
Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| C06 | Publication | ||
| PB01 | Publication | ||
| C10 | Entry into substantive examination | ||
| SE01 | Entry into force of request for substantive examination | ||
| C14 | Grant of patent or utility model | ||
| GR01 | Patent grant |