CN106249068B - Low-frequency measurement method for no-load characteristic of ferromagnetic element - Google Patents
Low-frequency measurement method for no-load characteristic of ferromagnetic element Download PDFInfo
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Abstract
A low-frequency measurement method for no-load characteristics of a ferromagnetic element mainly comprises the following steps: the first step is as follows: establishing a high-voltage side open-circuit equivalent circuit according to the T-shaped equivalent circuit, applying 2 low-frequency sine waves with different frequencies on a low-voltage side, and calculating the core loss under each frequency; the second step is that: calculating unit hysteresis and eddy current loss W generated in unit periodeAnd WhAnd calculating the core loss P converted to power frequencyCoren(ii) a The third step: calculating the exciting current I converted to power frequency according to the eddy current compensation algorithmexnHarmonic content K(k)Excitation voltage Un(ii) a The fourth step: calculating the no-load loss Pn(ii) a The fifth step: drawing PCoren‑Un，Iexn‑UnRelation curve, and K(k)‑UnTable of harmonic content. The method adopts the low-frequency power supply to replace a power-frequency power supply to carry out the test, so that the capacity of the test power supply can be reduced by times, the volume and the weight of test equipment can be reduced, and the test cost is lower.
Description
Technical Field
The invention belongs to the technical field of ferromagnetic element no-load characteristic measurement, mainly comprises no-load loss, excitation characteristic and no-load current harmonic content measurement, and particularly relates to ferromagnetic elements such as a transformer, a mutual inductor, a reactor and the like.
Background
Ferromagnetic elements such as transformers, reactors and the like are used as the most important power transmission and transformation equipment in a power system, and the performance of the ferromagnetic elements directly influences the safe and economic operation of the power system. The no-load loss, excitation characteristics and no-load current harmonic content of the ferromagnetic element are important indexes for reflecting the performance of the iron core of the ferromagnetic element. GB1094.1-2013 power transformer first part: general guidelines, which require no-load loss and no-load current measurement as routine tests, can be used to inspect and find local defects and global defects in the magnetic circuit of the test article. The test guide of the JB/T501-2006 power transformer provides: when no-load test is carried out, rated voltage with rated frequency is supplied to a high-voltage side winding (generally a low-voltage winding) in each winding of a test sample, and the other windings are opened; the measurement of the no-load current harmonic of the transformer is a special test, and the saturation degree of the iron core is checked by detecting the composition and the value of the no-load current harmonic, so that the rationality of the design is verified. Section 1 of the experimental guide for the GB22071.1-2008 transformer: current transformers and GB22071.2-2008 mutual inductor test guide 2 part: voltage transformers "all specify the need for excitation characteristic testing of voltage (current) transformers. GB 1094.6-2011 power transformer part 6: the reactor "also stipulates that the reactor must perform no-load loss measurement. However, with the increase of the voltage level of the power grid, the voltage level and the capacity of ferromagnetic elements such as a transformer are gradually increased, and the capacity, the volume and the weight of test equipment required in the no-load test are often very large, so that the no-load test procedure is complex, and the personal safety of operators cannot be guaranteed.
Therefore, it is necessary to find a new testing method for the no-load characteristic of ferromagnetic components, which can simplify the testing process and reduce the weight and volume of the testing equipment.
Disclosure of Invention
Aiming at the defects of the existing ferromagnetic element no-load characteristic measuring method, the invention provides a ferromagnetic element no-load test by adopting a low-frequency power supply. As can be seen from E ═ 4.44fN Φ, the core saturation voltage of the ferromagnetic element is substantially proportional to the power supply frequency, and under the excitation of the low-frequency power supply, the power supply voltage can be greatly reduced, while the no-load current is substantially unchanged, so that the capacity of the test power supply can be reduced by times. And measuring the no-load loss, the no-load current and the harmonic characteristics thereof under the low frequency, and calculating the no-load loss, the no-load current and the harmonic contents thereof converted to the power frequency test condition according to a related algorithm, thereby achieving the purpose of replacing the power frequency test with the low frequency test. Tests prove that the method has better consistency with a power frequency test method directly adopted.
In order to achieve the purpose, the invention adopts the following technical scheme:
a low-frequency measurement method for no-load characteristics of a ferromagnetic element is characterized by comprising the following steps:
1. an equivalent circuit model of the open circuit on the high-voltage side of the ferromagnetic element is established, and is shown in figure 1. Wherein R isdcIs a direct current resistance on the winding, LσFor leakage inductance of the side winding, ReNonlinear inductor L with hysteresis loop for equivalent resistance of eddy current lossmFor exciting inductance, hysteresis loss PhIs contained in LmIn (1). i.e. iex(t) is an excitation current, im(t) is a flow through LmMagnetizing current of ie(t) is the eddy current loss equivalent current, u (t) is the excitation voltage applied to the winding;
2. the no-load loss of the ferromagnetic element is mainly core loss, and the core loss mainly comprises magnetic hysteresis loss and eddy current loss:
in the formula, PhAnd PeHysteresis loss and eddy current loss, respectively; ceDetermining the resistivity for the eddy current loss coefficient; chThe hysteresis loss coefficient and the material property are determined; b ismIs the peak value of the magnetic flux of the iron core; f is the frequency; v is the volume of the iron core; delta is the thickness of the silicon steel sheet; wh(W/Hz) and We(W/Hz2) Unit hysteresis and eddy current loss are generated for each magnetization period, respectively. Thus if B at different frequencies is guaranteedmIf they are consistent, W can be considerede、WhIs constant, and when the U/f under different frequencies is consistent in the test, B can be considered asmAre equal. W is determined by the core losses at two different frequencieshAnd WeA value of (d);
3. and (3) opening the high-voltage side of the winding, applying voltage to the low-voltage side, and recording voltage and current data when the U/f is equal under two different frequencies. Calculation formula of iron loss:
where u (t) is the voltage applied across the winding, iex(t) is the excitation current, IexIs its valid value;
4. calculating the corresponding iron loss under each frequency to obtain:
5. from equation (3), solving the equation can obtain WeAnd WhComprises the following steps:
6. thus, the iron loss at power frequency is translated:
wherein f isnA nominal frequency, typically 50Hz or 60 Hz;
7. iron loss current can be divided into hysteresis loss current and eddy current loss current:
in the formula IFe、Ih、IeFor effective value of corresponding current, from E to KvfNBmS, knowing that E is proportional to the frequency f, the eddy current loss current ieHysteresis loss current i proportional to the frequency first powerhIndependent of frequency. And because of B at different frequenciesmAre equal to each other, so that imAnd (3) equality, converting to the exciting current under the power frequency:
8. loss of current i due to eddy currentseProportional to the frequency first power, convert to the eddy current at power frequency:
Ien＝Ie·fn/f (7)
9. as shown in fig. 1, since the eddy current contains only the fundamental component, it is only necessary to compensate the eddy current to the fundamental component of the excitation current when calculating the excitation current, and the phasor diagram is as shown in fig. 2, and is converted to the fundamental component of the excitation current at power frequency:
10. converting to exciting current under power frequency:
wherein, Iex(k)The current effective value of the kth harmonic wave under low frequency is obtained;
11. percent of no-load current harmonics:
K(k)the kth harmonic current accounts for the effective value of the fundamental current, and even harmonic content is the same as that of the fundamental current due to symmetrical positive and negative semi-axes of the waveformThis is zero. Therefore k is 1,3,5,7 …, k>1 hour, the amplitude of the idle current higher harmonic under low frequency and power frequency excitation is equal, i.e. Iexn(k)＝Iex(k)；
12. Converting to no-load loss at rated frequency:
13. because the voltage drop on the leakage inductance is very small and can be ignored when the leakage inductance is in no load, the leakage inductance is converted into the excitation voltage under the rated frequency:
Un＝E·fn/f+Iexn·Rdc(12)。
thus, the excitation voltage U converted to power frequency can be obtainednThe corresponding relation between the power frequency excitation voltage effective value and the no-load loss, the excitation current and the no-load current harmonic content under the power frequency achieves the purpose of replacing the power frequency test by adopting a low frequency test.
Compared with the prior art, the invention has the following advantages:
1. the low-frequency sine wave power supply is adopted for testing, so that the capacity, volume and weight of the testing power supply can be reduced by times, the testing process is more convenient, and the cost is lower;
2. the testing voltage is reduced, the requirement on the insulation performance of the testing equipment is low, and the safety of testing personnel is guaranteed.
Drawings
In order to make the method and principle of the present invention for measuring the no-load characteristic of a ferromagnetic element clearer, the present invention will be further described in detail with reference to the accompanying drawings, wherein:
fig. 1 is an equivalent circuit diagram of an open circuit on a high-voltage side of a ferromagnetic element according to an embodiment of the present invention;
fig. 2 is a phasor diagram illustrating field current compensation for a ferromagnetic element according to an embodiment of the present invention;
fig. 3 is a schematic diagram of a preferred embodiment of a low-frequency measurement method for an unloaded characteristic of a ferromagnetic element according to an embodiment of the present invention;
fig. 4 is a schematic diagram of a method for measuring an unloaded characteristic of a ferromagnetic element according to an embodiment of the present invention;
fig. 5 is a comparison between the measurement by the method and the actual measurement at power frequency provided by the embodiment of the present invention, (a) is a comparison between no-load loss measurement, and (b) is a comparison between excitation characteristic measurement.
Detailed Description
In order to enable a person skilled in the art to better understand the technical solution of the present invention, the following will clearly and completely describe the technical solution in the embodiments of the present invention with reference to the accompanying drawings and the detailed description, and it is obvious that the described embodiments are only a part of the embodiments of the present invention, and not all embodiments. All other embodiments, which can be derived by a person skilled in the art from the embodiments given herein without making any creative effort, shall fall within the protection scope of the present invention.
The measurement process is as follows:
fig. 4 is a schematic view of the measurement method of the present invention.
Step 100: according to the T-type equivalent circuit model, an equivalent circuit with one side (high voltage side) of the ferromagnetic element open is established, as shown in FIG. 1, wherein RdcIs a direct current resistance on the winding, LσFor leakage inductance of the side winding, ReNonlinear inductor L with hysteresis loop for equivalent resistance of eddy current lossmFor exciting inductance, hysteresis loss PhIs contained in LmIn (1). i.e. iex(t) is an excitation current, im(t) is a flow through LmMagnetizing current of ie(t) is the eddy current loss equivalent current, u (t) is the excitation voltage applied to the winding;
step 200: a schematic diagram of a measurement process of a preferred embodiment provided by the invention is shown in fig. 2, a high-voltage side is open-circuited, a low-frequency sine wave with 2 frequencies is applied to a low-voltage side (U/f is ensured to be equal under different frequencies), a data acquisition device records corresponding voltage and current data, and the iron core loss under each frequency is calculated according to a formula (2);
step 300: the unit hysteresis loss W in each magnetization period is calculated from the expressions (3) to (4)hAnd eddy current loss We；
Step 400: calculating the core loss P converted to power frequency according to the formula (5)Coren；
Step 500: calculating the eddy current I converted to power frequency according to the formulas (6) to (8)eFundamental component of exciting current Iexn(1)；
Step 600: calculating the exciting current I converted to power frequency according to the formulas (9) to (10)exnAnd its harmonic content K(k)；
Step 700: calculating the no-load loss P converted to power frequency according to the formula (11)n；
Step 800: calculating the excitation voltage effective value U converted to power frequency according to the formula (12)n；
Step 900: drawing PCoren-Un，Iexn-UnRelation curve, and K(k)-UnTable of harmonic content.
The foregoing are merely exemplary embodiments of the present invention, which enable those skilled in the art to understand or practice the present invention. Various modifications to these embodiments will be readily apparent to those skilled in the art, and the generic principles defined herein may be applied to other embodiments without departing from the spirit or scope of the invention. Thus, the present invention is not intended to be limited to the embodiments shown herein but is to be accorded the widest scope consistent with the principles and novel features disclosed herein.
Claims (5)
1. A low-frequency measurement method for the no-load characteristic of a ferromagnetic element is characterized by comprising the following steps:
the method comprises the following steps: establishing a high-voltage side open circuit equivalent circuit according to the T-shaped equivalent circuit, wherein the high-voltage side open circuit equivalent circuit is an excitation inductorL mEquivalent resistance to eddy currentR eAfter parallel connection, the direct current resistance of the winding is connectedR dcAnd leakage inductance of windingL σSeries formation, hysteresis lossesP hIncluded in the exciting inductanceL mIn the low voltage side, 2 different frequencies are appliedThe core loss at each frequency is calculated, wherein:
according to
Calculating the iron core loss under each frequency;
in the formula (I), the compound is shown in the specification,u(t) Is the voltage applied across the winding,i ex(t) Is the current of the excitation current and is,I exis its valid value;
step two: calculating the core loss at different and equal frequencies by interpolation, and calculating the unit hysteresis and eddy current loss W generated in unit period under different voltageseAnd WhAnd calculating the core loss converted to the power frequencyP CorenWherein:
according to
Calculating unit magnetic hysteresis and eddy current loss W generated by unit period under different voltageseAnd Wh；
According to
Calculating the core loss converted to power frequencyP Coren；
Wherein the content of the first and second substances,f n at a nominal frequency, either 50Hz or 60Hz,Ein order to induce an electromotive force, a magnetic field is generated,fis the applied power frequency;
step three: calculating the exciting current converted to power frequency according to the algorithm of converting eddy current compensation to exciting current fundamental componentI exnHarmonic contentK(k) Excitation voltageU nWherein:
according to
，
Calculating the exciting current converted to power frequencyI exn；
According to
Calculating the exciting current converted to power frequencyK(k )；
According to
Calculating the exciting voltage converted to power frequencyU n；
Wherein the content of the first and second substances,
is the fundamental component of the exciting current under the power frequency,
is the effective value of the fundamental component of the exciting current at low frequency,
for converting the effective value of the eddy current under the power frequency,
is an effective value of eddy current loss current at low frequencies,
is the phase difference between the eddy current at low frequency and the fundamental component of the excitation current,
is the k-th harmonic effective value of the exciting current under power frequency,
the effective value of the kth harmonic current of the exciting current under low frequency;
step four: according to pairsCalculating no-load loss by converting iron loss and copper loss under power frequencyP nWherein according to
Calculating no-load lossP n；
Step five: drawingP Coren-U n，I exn-U nA relation curve, andK(k)-U ntable of harmonic content.
2. The method for low frequency measurement of unloaded characteristic of a ferromagnetic element as claimed in claim 1, wherein said core loss of step one is to ensure that U/f of the ferromagnetic element is equal at different frequencies to ensure that the magnetic flux B at different frequencies is equalmCore loss under equal conditions.
3. The method for measuring low frequency of no-load characteristic of ferromagnetic element according to claim 1, wherein We and Wh in said second step are obtained by solving a system of core loss equations of two frequencies.
4. A method for low frequency measurement of unloaded characteristic of a ferromagnetic element as set forth in claim 1, wherein said eddy current compensation algorithm of step three compensates the eddy current to the fundamental component of the excitation current only because the eddy current contains only the fundamental component.
5. A low frequency measurement method of no-load characteristics of a ferromagnetic element according to claim 1, wherein said copper loss of step four is calculated by substituting the excitation current converted to power frequency into ohm's law.
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| CN106908745B (en) * | 2017-01-10 | 2019-05-28 | 云南电力试验研究院(集团)有限公司 | A kind of test and calculation method of the ferromagnetic element excitation property based on low-frequency square-wave and no-load loss |
| CN107102229B (en) * | 2017-05-26 | 2020-09-11 | 国家电网公司 | Method for realizing transformer model for no-load switching transient calculation |
| CN108231389B (en) * | 2017-05-31 | 2019-12-27 | 上海申世电气有限公司 | Filter reactor iron core loss design method |
| RU2755053C1 (en) * | 2020-12-14 | 2021-09-13 | Федеральное государственное бюджетное образовательное учреждение высшего образования Иркутский государственный университет путей сообщения (ФГБОУ ВО ИрГУПС) | Method for determining magnetic losses in a transformer |
| RU2764780C1 (en) * | 2021-02-05 | 2022-01-21 | Федеральное государственное бюджетное образовательное учреждение высшего образования Иркутский государственный университет путей сообщения (ФГБОУ ВО ИрГУПС) | Method for determining the indicator of the degree of magnetic induction in hysteresis losses for steel of a transformer core |
Citations (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US5617024A (en) * | 1993-10-12 | 1997-04-01 | The United States Of America As Represented By The United States National Aeronautics And Space Administration | Flux focusing eddy current probe |
| CN101650398B (en) * | 2009-06-03 | 2011-06-15 | 云南电力试验研究院（集团）有限公司电力研究院 | Test method and compensation calculation method for measuring voltage-current characteristic of ferromagnetic element by low-frequency variable-frequency power source |
| CN105510742A (en) * | 2015-12-08 | 2016-04-20 | 云南电力试验研究院(集团)有限公司 | Experiment method and analysis calculation method for testing transformer volt-ampere characteristic by using low-frequency power supply |
-
2016
- 2016-07-08 CN CN201610536618.9A patent/CN106249068B/en active Active
Patent Citations (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US5617024A (en) * | 1993-10-12 | 1997-04-01 | The United States Of America As Represented By The United States National Aeronautics And Space Administration | Flux focusing eddy current probe |
| CN101650398B (en) * | 2009-06-03 | 2011-06-15 | 云南电力试验研究院（集团）有限公司电力研究院 | Test method and compensation calculation method for measuring voltage-current characteristic of ferromagnetic element by low-frequency variable-frequency power source |
| CN105510742A (en) * | 2015-12-08 | 2016-04-20 | 云南电力试验研究院(集团)有限公司 | Experiment method and analysis calculation method for testing transformer volt-ampere characteristic by using low-frequency power supply |
Non-Patent Citations (1)
| Title |
|---|
| 变压器空载损耗中的磁滞损耗和涡流损耗的区分;秦大为等;《变压器》;20070930;第44卷(第9期);第26-28页 * |
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