CN110161435A - A kind of power transformer remanent magnetism magnitude estimation method based on winding deformation measurement - Google Patents
A kind of power transformer remanent magnetism magnitude estimation method based on winding deformation measurement Download PDFInfo
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- CN110161435A CN110161435A CN201910512316.1A CN201910512316A CN110161435A CN 110161435 A CN110161435 A CN 110161435A CN 201910512316 A CN201910512316 A CN 201910512316A CN 110161435 A CN110161435 A CN 110161435A
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- G01R—MEASURING ELECTRIC VARIABLES; MEASURING MAGNETIC VARIABLES
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Abstract
The present invention provides a kind of power transformer remanent magnetism magnitude estimation method based on winding deformation measurement, and different size of remanent magnetism B is preset in the minds of transformer fe to power transformer excitation using the continuously adjustable low-frequency sine power supply of voltage, frequencyr, winding frequency response curve of the measuring transformer under different remanent magnetism sizes, resonance dot frequency f of the reading winding frequency response curve in low-frequency range0, to obtain a series of discrete (Br, f0) value, establish BrWith f0Between relation curve graph model.After model foundation, the remanent magnetism size that winding frequency response curve estimates transformer core in the resonance dot frequency of low-frequency range can be read by the winding frequency response curve of measuring transformer.The present invention, which need to only measure a transformer winding frequency response curve, can effectively, quickly estimate the size of power transformer iron core remanent magnetism, easy to operate, high-efficient, be of great significance for analysis power transformer iron core remanent magnetism situation.
Description
Technical field
The present invention relates to power transformer remanent magnetism to estimate field, specifically a kind of power transformer based on winding deformation measurement
Device remanent magnetism magnitude estimation method.
Background technique
The device with closed iron magnetic material core construction this for transformer, in pilot projects such as D.C. resistance tests
During being run afterwards with excision, due to the closure of its core construction and the hysteresis characteristic of ferromagnetic material, it will be present in iron core
Remanent magnetism, the large-scale power transformer more for umber of turn, the lower remanent magnetism generated of dc magnetization effect are also more.If transformer
There are remanent magnetism, empty combined floodgate transformer will appear larger excitation surge current, have an important influence on to alternating current-direct current power grid.Therefore, compared with subject to
Really judge transformer remanent magnetism size, for reduce transformer put into operation when excitation surge current, ensure transformer safety stable operation have
It is significant.
However remanent magnetism does not simply fail to directly measure at present, and lacks the exact technical of transformer remanent magnetism measuring and calculating, causes
After live straight resistance test, it is a variety of after breaker open operation etc. under the conditions of remanent magnetism have no way of finding out about it.
Summary of the invention
In view of the above shortcomings of the prior art, the present invention provides a kind of power transformers based on winding deformation measurement
Device remanent magnetism magnitude estimation method, this method is easy to operate, high-efficient, can effectively, quickly estimate power transformer iron core remanent magnetism
Size, for inhibiting the excitation surge current of transformer, the remanent magnetism for reducing transformer influences, and is of great significance.
A kind of power transformer remanent magnetism magnitude estimation method based on winding deformation measurement, includes the following steps:
Step 1: determining excitation source frequency f, pressure side and corresponding transformer voltage rating UN, transformer rated frequency fN、
The rated flux density B of transformer core silicon steel sheetN, measuring transformer electrical steel piece is in a series of magnetic hysteresis that frequency is f
Loop line needs to be respectively labeled as S comprising K hysteresis loop altogether according to modeling1、S2、S3、…、SK；
Step 2: record hysteresis loop S1Corresponding remanent magnetism Br1With peakflux density B1；
Step 3: sufficiently being demagnetized using direct current demagnetization method or AC demagnetization method to transformer；
Step 4: using frequency is the low-frequency sine power supply of f to static exciter, and voltage isIn electricity
After stream lives through several cycles, external drive power supply is cut off in current zero-crossing point using power electronic devices control, thus
It is B that size is produced in the minds of transformer fer1Remanent magnetism；
Step 5: the winding frequency response curve of measuring transformer records the resonance dot frequency f of low-frequency range01；
Step 6: record hysteresis loop S2Corresponding remanent magnetism Br2With peakflux density B2；
Step 7: repeating step 3~5 and obtain f02；
Step 8: according to this, available a series of (Br, f0) value: (Br1, f01)、(Br2, f02)、…、(BrK, f0K)；
Step 9: B is fitted by discrete pointrWith f0Graph of relation；
Step 10: when estimation transformer core remanent magnetism, measuring transformer winding frequency response curve simultaneously reads low band resonance point
Frequency size, can be by BrWith f0Graph of relation estimate the remanent magnetism size of transformer core.
Further, the frequency f of driving source described in the step 1 is determined by the actual parameter of transformer.Wherein fmaxFor the maximum frequency of driving source, UmaxFor the maximum output voltage of driving source, UNFor transformation
The voltage rating of device pressurization winding, fNFor the rated frequency of transformer.
Further, in the step 1 hysteresis loop item number K by being finally fitted BrWith f0(B needed for graph of relationr, f0)
The quantity of discrete point determines.
Further, in the step 1 K hysteresis loop be since silicon steel sheet magnetic neutral state, then it is ascending, no
Under repeated action with the positive and negative maximum field of size, a series of obtained ascending normal hysteresis loops.
Further, it is to replace transformer complete machine by the hysteresis loop of monolithic silicon steel sheet that remanent magnetism is preset in the step 4
Hysteresis loop realize, in engineering for estimating that this processing mode is reasonable.
Further, the test method of transformer winding frequency response curve answers identical, transformer tap in the whole process
Switch should be placed in same gear, be typically disposed in 1 grade, for single-phase transformer, when winding frequency response curve measures signal from subject around
Group tail end injection, head end measurement, the tail end ground connection of non-subject winding, head end are hanging；For three-phase transformer, when measurement signal from
It is tested winding subject phase tail end injection, head end measurement, (winding is for non-subject winding neutral point (winding is star-like connection) or B phase
Triangle connection) it is grounded, other terminals are hanging.
Further, the measurement frequency band of winding frequency response curve described in the step 5 is 20Hz~1MHz, and winding frequency response is bent
The low-frequency range of line is 20Hz~1kHz.
Technical solution of the present invention have it is below the utility model has the advantages that
1, the present invention is suitable for estimating the remanent magnetism 110kV and above three-phase and single phase power transformer iron core
Size；
2, after the graph of relation model foundation of transformer core remanent magnetism and winding frequency response curve low band resonance dot frequency,
First winding frequency response curve only need to be measured i.e. and can determine whether that transformer core whether there is remanent magnetism, it is easy to operate, it is high-efficient；
3, in this technology scheme of the invention, driving source using low-frequency sine power supply as power transformer is greatly reduced
Requirement to electric power output voltage and capacity, simultaneously because supply frequency is low, power electronic devices is in current zero-crossing point time control
Switch cutoff power supply processed is also easy to accomplish；
4, in this technology scheme of the invention, the hysteresis loop of transformer complete machine is replaced using the hysteresis loop of monolithic silicon steel sheet,
The complexity of measurement work is greatly reduced, while the needs that remanent magnetism is estimated in engineering can also be met；
5, in this technology scheme of the invention, the mode of connection and the tap switch position of the test of transformer winding frequency response curve are specified
It sets, influences when avoiding test because of the difference of test connection and position of tapping switch to winding frequency response curve test result.
Detailed description of the invention
Fig. 1 is that the present invention is based on the power transformer remanent magnetism magnitude estimation processes of winding deformation measurement；
Fig. 2 is a series of normal hysteresis loops that the change of current becomes under electrical steel piece 0.1Hz in the embodiment of the present invention；
Fig. 3 is that the change of current becomes winding frequency response curve measurement result (20Hz~1kHz) in the embodiment of the present invention；
Fig. 4 is that the change of current becomes charge circuit schematic diagram in the embodiment of the present invention；
Fig. 5 is the relationship that the change of current becomes iron core remanent magnetism and winding frequency response curve low band resonance dot frequency in the embodiment of the present invention
Curve graph.
Specific embodiment
Below in conjunction with the attached drawing in the present invention, the technical solution in the present invention is clearly and completely described.
The presence of power transformer iron core remanent magnetism will lead to the reduction of static exciter inductance, therefore can be to transformer winding frequency
The low-frequency range for ringing curve has an impact.Theory and practice experience have shown that: transformer winding frequency response curve low-frequency range 20Hz~
1kHz has a resonance point, and the resonance dot frequency of transformer remanent magnetism and winding frequency response curve low-frequency range has dull corresponding relationship,
Transformer remanent magnetism is bigger, and the resonance dot frequency of winding frequency response curve low-frequency range is bigger.
Based on the above principles, the quasi- building transformer core remanent magnetism of the present invention and winding frequency response curve low band resonance dot frequency
Relation curve graph model, the estimation of iron core remanent magnetism size can be realized in the winding frequency response curve by measuring power transformer.
The present invention adopts the following technical scheme: using AC power source to power transformer excitation, in exciting current zero crossing
When by power electronic devices control remove excitation achieve the purpose that default remanent magnetism, at this time can be by the magnetic hysteresis of transformer core
Loop line obtains remanent magnetism size when excitation removes in transformer core.Power transformer is measured in different remanent magnetism size BrUnder around
Group frequency response curve, reads the resonance dot frequency f of winding frequency response curve low-frequency range0, available a series of discrete point (Br, f0),
To realize the relation curve graph model of building transformer core remanent magnetism and winding frequency response curve low band resonance dot frequency.
Referring to Figure 1, a kind of power transformer remanent magnetism magnitude estimation method based on winding deformation measurement of the present invention, wherein
Remanent magnetism of the one embodiment using the process estimation high-end Y/Y converter power transformer of one ± 800kV as shown in Figure 1, the transformer
Model ZZDFPZ-509300/500-800, combinations of voltages areIt is single-phase double
Winding transformer, the change of current become iron core rated flux density as 1.7T, and rated frequency 50Hz, net side position of tapping switch is placed in 1
Shelves.
The change of current becomes the silicon steel sheet model B27R090 that iron core uses, and using 0.1T as gradient, measures the change of current and becomes silicon steel
Piece peakflux density at 0.1Hz is a series of magnetization curves under 1T~1.8T, and measurement result is as shown in Figure 2.
The change of current is cashed when field carries out long after the measurement of partial discharge test of induced voltage band, and it is abundant that the change of current at this time becomes iron core experience
Demagnetization measures its winding frequency response curve it is considered that without remanent magnetism, and test equipment uses FRAX101, when test net side around
Group tail end 1.2 is grounded, and source side winding head end 1.1 is hanging, and signal is injected from valve side winding tail end 2.2, and head end 2.1 measures, scanning
Frequency is 20Hz~1MHz, intercepts the measurement result of wherein 20Hz~1kHz as shown in Fig. 3 Green curve, reads winding frequency response
Resonance dot frequency of the curve in low-frequency range, about 600Hz, therefore an available (Br, f0) discrete point (0,600).
Low-frequency sine power supply maximum output is 500V, in converter transformer valve side excitation, low-frequency sine power supply output frequency
ForExcitation source frequency is selected as 0.1Hz.
Choose peakflux density B1The change of current of=1T becomes electrical steel piece hysteresis loop, remanent magnetism Br1=0.42T.
After field shelf depreciation is cashed in the change of current, using low-frequency sine power supply to converter transformer valve side excitation, circuit theory signal
Figure as shown in figure 4, wherein DP be low-frequency power, K be power electronic devices control switch, 2.1,2.2 for converter transformer valve side around
Group terminal, 1.1,1.2 become source side winding terminal for the change of current, and the change of current becomes net side neutral point 1.2 and is grounded when test, and test voltage is aboutAfter undergoing several cycles, pass through power electronic devices control
System switch disconnects, and becomes iron core in the change of current at this time and produces Br1The remanent magnetism of=0.42T.
The winding frequency response curve of converter transformer valve side winding is measured, is intercepted in the wherein measurement result of 20Hz~1kHz such as Fig. 3
Shown in red curve, resonance dot frequency of the reading winding frequency response curve in low-frequency range, about 638Hz, therefore available one
(Br, f0) discrete point (0.42,638).
It is sufficiently demagnetized using AC demagnetization method or direct current demagnetization method exchange rheology.
Choose peakflux density B2The change of current of=1.1T becomes electrical steel piece hysteresis loop, remanent magnetism Br1=0.55T.
After field shelf depreciation is cashed in the change of current, using low-frequency sine power supply to converter transformer valve side excitation, test voltage is aboutAfter undergoing several cycles, pass through power electronic devices control
System switch disconnects, and becomes iron core in the change of current at this time and produces Br1The remanent magnetism of=0.55T.
The winding frequency response curve of converter transformer valve side winding is measured, is intercepted in the wherein measurement result of 20Hz~1kHz such as Fig. 3
Shown in blue curve, resonance dot frequency of the reading winding frequency response curve in low-frequency range, about 652Hz, therefore available one
(Br, f0) discrete point (0.55,652).
Likewise, a series of available (Br, f0) discrete point (0,600), (0.42,638), (0.55,652), (0.63,
664), (0.72,676), (0.82,690), (0.91,705), (1.02,735), (1.12,785), (1.22,852), (1.26,
880)。
It establishes the change of current and becomes iron core remanent magnetism BrWith winding frequency response curve low band resonance dot frequency f0Relation curve graph model,
As shown in Figure 5.
After model foundation, need to only measure first winding frequency response curve can estimate that the change of current becomes iron core remanent magnetism size, such as certain
Measuring converter transformer valve side winding frequency response curve low band resonance dot frequency is 750Hz, and the change of current becomes iron core remanent magnetism size as shown in Figure 5
About 1.05T.
The above description is merely a specific embodiment, but scope of protection of the present invention is not limited thereto, any
Belong to those skilled in the art in the technical scope disclosed by the present invention, any changes or substitutions that can be easily thought of, all answers
It is included within the scope of the present invention.
Claims (7)
1. a kind of power transformer remanent magnetism magnitude estimation method based on winding deformation measurement, it is characterised in that: including walking as follows
It is rapid:
Step 1: determining excitation source frequency f, pressure side and corresponding transformer voltage rating UN, transformer rated frequency fN, transformation
The rated flux density B of device electrical steel pieceN, measuring transformer electrical steel piece is a series of hysteresis loop of f in frequency,
It is needed to be respectively labeled as S comprising K magnetization curve altogether according to modeling1、S2、S3、…、SK；
Step 2: record hysteresis loop S1Corresponding remanent magnetism Br1With peakflux density B1；
Step 3: sufficiently being demagnetized using direct current demagnetization method or AC demagnetization method to transformer；
Step 4: using frequency is the low-frequency sine power supply of f to static exciter, and voltage isIt is passed through in electric current
After going through several cycles, external drive power supply is cut off in current zero-crossing point using power electronic devices control, is thus being become
It is B that size is produced in depressor iron corer1Remanent magnetism；
Step 5: the winding frequency response curve of measuring transformer records the resonance dot frequency f of low-frequency range01；
Step 6: record hysteresis loop S2Corresponding remanent magnetism Br2With peakflux density B2；
Step 7: repeating step 3~5 and obtain f02；
Step 8: according to this, available a series of (Br, f0) value: (Br1, f01)、(Br2, f02)、…、(BrK, f0K)；
Step 9: B is fitted by discrete pointrWith f0Graph of relation；
Step 10: when estimation transformer core remanent magnetism, measuring transformer winding frequency response curve simultaneously reads low band resonance dot frequency
Size, can be by BrWith f0Graph of relation estimate the remanent magnetism size of transformer core.
2. the power transformer remanent magnetism magnitude estimation method as described in claim 1 based on winding deformation measurement, feature exist
In: the frequency f of driving source described in the step 1 is determined by the actual parameter of transformer:Wherein
fmaxFor the maximum frequency of driving source, UmaxFor the maximum output voltage of driving source, UNFor transformer pressurize winding voltage rating,
fNFor the rated frequency of transformer.
3. the power transformer remanent magnetism magnitude estimation method as described in claim 1 based on winding deformation measurement, feature exist
In: hysteresis loop item number K is by being finally fitted B in the step 1rWith f0(B needed for graph of relationr, f0) discrete point quantity it is true
It is fixed.
4. the power transformer remanent magnetism magnitude estimation method as described in claim 1 based on winding deformation measurement, feature exist
In: in the step 1 K hysteresis loop be since silicon steel sheet magnetic neutral state, then it is ascending, it is different size of it is positive and negative most
Under the repeated action in big magnetic field, a series of obtained ascending normal hysteresis loops.
5. the power transformer remanent magnetism magnitude estimation method as described in claim 1 based on winding deformation measurement, feature exist
In: it is to replace the hysteresis loop of transformer complete machine come real by the hysteresis loop of monolithic silicon steel sheet that remanent magnetism is preset in the step 4
It is existing.
6. the power transformer remanent magnetism magnitude estimation method as described in claim 1 based on winding deformation measurement, feature exist
In: the test method of transformer winding frequency response curve is identical in the whole process, and sub-connecting switch of transformer is placed in same gear,
For single-phase transformer, signal is measured from subject winding tail end injection, head end when winding frequency response curve measures, non-subject winding
Tail end ground connection, head end are hanging；For three-phase transformer, signal is from subject winding subject phase tail end injection when measurement, head end measurement,
Non- subject winding neutral point or B phase are grounded, and other terminals are hanging.
7. the power transformer remanent magnetism magnitude estimation method as described in claim 1 based on winding deformation measurement, feature exist
In: the measurement frequency band of winding frequency response curve described in the step 5 is 20Hz~1MHz, and the low-frequency range of winding frequency response curve is
20Hz~1kHz.
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Cited By (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN110646754A (en) * | 2019-09-27 | 2020-01-03 | 国网四川省电力公司电力科学研究院 | Frequency response-based transformer residual magnetism detection method and system |
| CN111044945A (en) * | 2019-12-26 | 2020-04-21 | 武汉理工大学 | Transformer residual magnetism determination method based on small signal measurement excitation inductance |
| CN111556643A (en) * | 2020-05-09 | 2020-08-18 | 清华大学 | Magnetic field generation method and synchrotron |
| CN112068050A (en) * | 2020-09-10 | 2020-12-11 | 云南电网有限责任公司电力科学研究院 | Transformer residual magnetism quantitative evaluation and elimination method |
Citations (5)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| DE19641116A1 (en) * | 1996-10-05 | 1998-04-09 | Christoph Ploetner | Detection process for transformer core remanence flux |
| CN106093811A (en) * | 2016-06-01 | 2016-11-09 | 国网河北省电力公司电力科学研究院 | A kind of transformer core remanent magnetism detection method based on method of least square |
| CN107656221A (en) * | 2017-09-08 | 2018-02-02 | 国网江苏省电力公司电力科学研究院 | A kind of transformer core remanent magnetism evaluation method based on minor loop's slope |
| CN109254253A (en) * | 2018-10-19 | 2019-01-22 | 国网江苏省电力有限公司电力科学研究院 | The device and control method of a kind of assessment of power transformer remanent magnetism amount and demagnetization |
| CN109444776A (en) * | 2018-11-05 | 2019-03-08 | 国网江苏省电力有限公司电力科学研究院 | Three-phase full-bridge converter iron core remanent magnetism measuring method, system and storage medium |
-
2019
- 2019-06-13 CN CN201910512316.1A patent/CN110161435B/en active Active
Patent Citations (5)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| DE19641116A1 (en) * | 1996-10-05 | 1998-04-09 | Christoph Ploetner | Detection process for transformer core remanence flux |
| CN106093811A (en) * | 2016-06-01 | 2016-11-09 | 国网河北省电力公司电力科学研究院 | A kind of transformer core remanent magnetism detection method based on method of least square |
| CN107656221A (en) * | 2017-09-08 | 2018-02-02 | 国网江苏省电力公司电力科学研究院 | A kind of transformer core remanent magnetism evaluation method based on minor loop's slope |
| CN109254253A (en) * | 2018-10-19 | 2019-01-22 | 国网江苏省电力有限公司电力科学研究院 | The device and control method of a kind of assessment of power transformer remanent magnetism amount and demagnetization |
| CN109444776A (en) * | 2018-11-05 | 2019-03-08 | 国网江苏省电力有限公司电力科学研究院 | Three-phase full-bridge converter iron core remanent magnetism measuring method, system and storage medium |
Non-Patent Citations (3)
| Title |
|---|
| NILANGA ABEYWICKRAMA等: "Effect of Core Magnetization on Frequency Response Analysis (FRA) of Power Transformers", 《IEEE TRANSACTIONS ON POWER DELIVERY》 * |
| 李景丽等: "电力变压器铁心剩磁测量方法研究综述", 《高压电器》 * |
| 陶风波等: "基于局部磁滞回线斜率的变压器铁心剩磁估算", 《变压器》 * |
Cited By (6)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN110646754A (en) * | 2019-09-27 | 2020-01-03 | 国网四川省电力公司电力科学研究院 | Frequency response-based transformer residual magnetism detection method and system |
| CN111044945A (en) * | 2019-12-26 | 2020-04-21 | 武汉理工大学 | Transformer residual magnetism determination method based on small signal measurement excitation inductance |
| CN111556643A (en) * | 2020-05-09 | 2020-08-18 | 清华大学 | Magnetic field generation method and synchrotron |
| CN111556643B (en) * | 2020-05-09 | 2021-10-22 | 清华大学 | Magnetic field generation method and synchrotron |
| CN112068050A (en) * | 2020-09-10 | 2020-12-11 | 云南电网有限责任公司电力科学研究院 | Transformer residual magnetism quantitative evaluation and elimination method |
| CN112068050B (en) * | 2020-09-10 | 2023-10-13 | 云南电网有限责任公司电力科学研究院 | Transformer remanence quantitative evaluation and elimination method |
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