CN106558406B - A kind of suppressing method of power transformer D.C. magnetic biasing - Google Patents
A kind of suppressing method of power transformer D.C. magnetic biasing Download PDFInfo
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- CN106558406B CN106558406B CN201610882024.3A CN201610882024A CN106558406B CN 106558406 B CN106558406 B CN 106558406B CN 201610882024 A CN201610882024 A CN 201610882024A CN 106558406 B CN106558406 B CN 106558406B
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- 238000000034 method Methods 0.000 title claims abstract description 21
- 238000004804 winding Methods 0.000 claims abstract description 70
- 230000007935 neutral effect Effects 0.000 claims abstract description 27
- XEEYBQQBJWHFJM-UHFFFAOYSA-N Iron Chemical group [Fe] XEEYBQQBJWHFJM-UHFFFAOYSA-N 0.000 claims description 4
- 238000004891 communication Methods 0.000 claims description 3
- 238000012544 monitoring process Methods 0.000 claims description 3
- 230000002401 inhibitory effect Effects 0.000 abstract description 4
- 230000005764 inhibitory process Effects 0.000 abstract description 2
- 230000001629 suppression Effects 0.000 description 6
- 238000009434 installation Methods 0.000 description 4
- 230000005540 biological transmission Effects 0.000 description 3
- 239000003990 capacitor Substances 0.000 description 2
- 238000004519 manufacturing process Methods 0.000 description 2
- 230000009286 beneficial effect Effects 0.000 description 1
- 230000000903 blocking effect Effects 0.000 description 1
- 238000011217 control strategy Methods 0.000 description 1
- 238000013461 design Methods 0.000 description 1
- 238000011161 development Methods 0.000 description 1
- 238000010586 diagram Methods 0.000 description 1
- 230000000694 effects Effects 0.000 description 1
- 238000005516 engineering process Methods 0.000 description 1
- 230000006698 induction Effects 0.000 description 1
- 238000002955 isolation Methods 0.000 description 1
- 230000005405 multipole Effects 0.000 description 1
- 238000013021 overheating Methods 0.000 description 1
- 238000006467 substitution reaction Methods 0.000 description 1
- 230000009466 transformation Effects 0.000 description 1
- 230000003313 weakening effect Effects 0.000 description 1
Classifications
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- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01F—MAGNETS; INDUCTANCES; TRANSFORMERS; SELECTION OF MATERIALS FOR THEIR MAGNETIC PROPERTIES
- H01F27/00—Details of transformers or inductances, in general
- H01F27/34—Special means for preventing or reducing unwanted electric or magnetic effects, e.g. no-load losses, reactive currents, harmonics, oscillations, leakage fields
- H01F27/38—Auxiliary core members; Auxiliary coils or windings
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- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01F—MAGNETS; INDUCTANCES; TRANSFORMERS; SELECTION OF MATERIALS FOR THEIR MAGNETIC PROPERTIES
- H01F27/00—Details of transformers or inductances, in general
- H01F27/34—Special means for preventing or reducing unwanted electric or magnetic effects, e.g. no-load losses, reactive currents, harmonics, oscillations, leakage fields
-
- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01F—MAGNETS; INDUCTANCES; TRANSFORMERS; SELECTION OF MATERIALS FOR THEIR MAGNETIC PROPERTIES
- H01F27/00—Details of transformers or inductances, in general
- H01F27/40—Structural association with built-in electric component, e.g. fuse
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- Engineering & Computer Science (AREA)
- Power Engineering (AREA)
- Control Of Electrical Variables (AREA)
Abstract
The invention discloses a kind of suppressing methods of power transformer D.C. magnetic biasing, the input and output of power transformer are three-phase, power transformer is made of three first windings and three secondary windings, the coiling tertiary winding is as DC compensation winding in the common core of power transformer, the DC current source of one current control of series connection access in the tertiary winding, and a DC current transformer is installed at the neutral point of the first winding, there are three the tertiary windings, adopts and is connected serially；The current polarity of DC current source output is opposite with the DC current polarity at transformer first winding neutral point.The present invention starts with from the internal structure of transformer body, carries out the inhibition of transformer DC magnetic bias, advantage of lower cost, and have good feasibility, dependable with function can be realized good D.C. magnetic biasing inhibitory effect.
Description
Technical Field
The invention relates to the technical field of high-voltage power transmission and transformation, in particular to a method for inhibiting direct-current magnetic bias of a power transformer.
Background
With the development of power systems, ultrahigh voltage and extra-high voltage direct current transmission technology is widely applied in China. However, in actual operation, when an extra-high voltage and ultra-high voltage direct current transmission system is in a monopolar ground loop operation mode or a bipolar unbalanced operation mode, a direct current magnetic bias phenomenon is easily caused to occur on a transformer of an alternating current substation around a converter station. In addition, the transformer generates a dc bias due to the geomagnetic induction current.
The transformer DC magnetic biasing shows that: 1) noise is increased; 2) aggravation of vibration; 3) local overheating; 4) causing distortion of the voltage waveform; 5) the transformer losses increase.
The existing methods for solving the problem of direct current magnetic biasing of the power transformer mainly comprise the following three methods:
1) connecting a resistor to a neutral point of the transformer;
2) a capacitor is connected to a neutral point of the transformer;
3) injecting reverse current into a neutral point of the transformer;
the method 1 has low cost and is easy to popularize. However, the direct current of the neutral point of other nearby transformers exceeds the standard, the direct current entering from the neutral point cannot be completely counteracted, the zero sequence reactance of an alternating current system is changed due to the access of the neutral point resistor, and the protection fixed value needs to be re-adjusted, so that the resistor parameter selection is complex.
The method 2 has a thorough blocking effect. However, in order to limit the overvoltage across the capacitor during a fault, a large-capacity voltage transformer needs to be added, a large installation space is required, and the cost is high.
The method 3 can flexibly control the reverse direct current injected into the neutral point according to the magnitude of the direct current, but the device implementation and control strategy is complex, the difficulty is high, and the manufacturing cost is high.
The methods are all provided with the suppression device on the neutral point of the transformer, which can cause the change of direct current flowing through the neutral points of the transformers at other positions, and meanwhile, the methods all take compensation, weakening and isolation of the direct current as starting points, belong to external treatment measures, and bring new power grid safety problems to different degrees.
Disclosure of Invention
The technical problem to be solved by the invention is to provide a method for inhibiting the direct current magnetic bias of a power transformer, which starts with the internal structure of a transformer body, inhibits the direct current magnetic bias of the transformer, has relatively low cost, good feasibility, reliability and practicability, and can realize good direct current magnetic bias inhibition effect.
In order to solve the technical problems, the technical scheme provided by the invention is as follows:
a method for suppressing DC magnetic bias of power transformer, the input and output of said power transformer are three-phase, the power transformer is composed of three primary windings and three secondary windings, the third winding is wound on the common iron core of the power transformer as DC compensation winding, a DC current source controlled by current is connected in series in the third winding, and a DC current transformer is installed at the neutral point of the primary winding,
the direct current transformer sends the measured direct current value to the direct current source, and the direct current source outputs direct current to the third winding according to the received direct current value;
three third windings are connected in series;
the polarity of the current output by the direct current source is opposite to that of the direct current at the neutral point of the primary winding of the transformer.
The value of the direct current output by the direct current source to the third winding is obtained by the following formula:
wherein,N 1 the number of turns of the primary winding is,N 3 is the number of turns of the third winding,I 1is the value of the direct current measured at the neutral point of the primary winding of the power transformer,I 3the value of the direct current output to the third winding by the direct current source.
The direct current source is provided with a communication interface and is used for sending information including a direct current value measured at a neutral point of the primary winding, a direct current value output by the direct current source and the working state of the direct current source to the monitoring background.
The power transformer is a three-phase transformer group consisting of a three-phase transformer or three single-phase transformers.
The three primary windings of the power transformer are connected according to a Y-type mode, and the three secondary windings are connected according to an △ -type mode.
The invention has the following beneficial effects:
1. starting from the internal structure of the transformer body, a direct current compensation winding is added, and the direct current measured by the neutral point of the transformer is taken as a control basis, so that the polarity of the direct current in each phase of compensation winding is opposite to and proportional to that of the direct current flowing through the neutral point of the transformer, and a good direct current magnetic bias suppression effect is achieved;
2. the addition of the direct current compensation winding does not change the current in the transformer, thereby not causing the obvious change of direct current in transformers at other positions;
3. the invention does not change the parameters of the power system and does not influence the prior configurations of external overvoltage protection, relay protection and the like, thereby greatly reducing the influence degree on the safety of the power grid.
Drawings
Fig. 1 is a schematic diagram of the operation of the present invention.
Detailed Description
The present invention is further described below in conjunction with the following figures and specific examples so that those skilled in the art may better understand the present invention and practice it, but the examples are not intended to limit the present invention.
As shown in fig. 1, the input and output of the power transformer used in the method for suppressing dc magnetic bias of a power transformer are all three phases, and a three-phase transformer group composed of three single-phase transformers or a three-phase transformer is used, and is composed of six windings wound on a common multi-pole iron core and placed in a single box.
Whether a three-phase transformer bank or a three-phase transformer, the three primary windings and the three secondary windings are respectively formed according to a specific connection mode, preferably, the three primary windings are connected according to a Y-shaped mode, and the three secondary windings are connected according to an △ -shaped mode.
Winding a third winding on a common iron core of the power transformer to serve as a direct current compensation winding, connecting a direct current source controlled by current in series in the third winding, and installing a direct current transformer at a neutral point of a primary winding, wherein three third windings are connected in series;
the direct current transformer sends the measured direct current value to the direct current source, and the direct current source outputs direct current to the third winding according to the received direct current value;
the polarity of the current output by the direct current source is opposite to that of the direct current at the neutral point of the primary winding of the transformer.
The DC current value output by the DC current source to the third windingI 3Obtained from the following equation:
wherein,N 1 the number of turns of the primary winding is,N 3 is the number of turns of the third winding,I 1is the value of the direct current measured at the neutral point of the primary winding of the power transformer,I 3the value of the direct current output to the third winding by the direct current source.
Further, the direct current source is provided with a communication interface for sending information such as a direct current value measured at a neutral point of the primary winding, a direct current value output by the direct current source, and a working state of the direct current source to the monitoring background.
The embodiment starts from the internal structure of the transformer body, adds a third winding as a direct current compensation winding, connects a direct current source controlled by current in series in the direct current compensation winding, and takes the direct current measured by the neutral point of the power transformer as the control basis, so that the direct current in each phase of compensation winding is opposite in polarity and proportional to the direct current flowing through the neutral point of the power transformer, and the compensation magnetomotive force of each phase of compensation winding is equal to the direct current magnetomotive force in each phase of winding on the primary side of the power transformer.
In the embodiment, the direct current magnetic bias suppression is performed by adding the direct current compensation winding, and the current in the power transformer is not changed, so that the direct current in the power transformer at other positions is not obviously changed.
The installation of the direct current magnetic bias suppression device adopting the method of the embodiment is carried out in the manufacturing process of the transformer, compared with other methods, the installation difficulty of the direct current magnetic bias suppression device is low, the precision and the reliability can be better ensured, meanwhile, the direct current magnetic bias suppression device can be integrated on the transformer body through the optimized design, and the installation space is saved.
The embodiment does not change the parameters of the power system, does not influence the existing configurations such as external overvoltage protection and relay protection, and reduces the influence degree on the safety of the power grid to the minimum.
The above-mentioned embodiments are merely preferred embodiments for fully illustrating the present invention, and the scope of the present invention is not limited thereto. The equivalent substitution or change made by the technical personnel in the technical field on the basis of the invention is all within the protection scope of the invention. The protection scope of the invention is subject to the claims.
Claims (5)
1. A method for suppressing the DC magnetic bias of power transformer features that three primary windings and three secondary windings are wound on the shared iron core of each primary and secondary windings, three third windings are serially connected to each other, a DC current source controlled by current is serially connected to the serial circuit formed by three third windings, and a DC current transformer is installed at the neutral point of primary winding,
the direct current transformer sends the measured direct current value to the direct current source, and the direct current source outputs direct current to the third winding according to the received direct current value;
the polarity of the current output by the direct current source is opposite to that of the direct current at the neutral point of the primary winding of the transformer.
2. The method for suppressing dc magnetic bias of a power transformer according to claim 1, wherein the value of the dc current outputted from said dc current source to said third winding is obtained by the following equation:
wherein N is1Number of primary winding turns, N3Is the number of turns of the third winding, I1For the value of the direct current measured at the neutral point of the primary winding of the power transformer, I3The value of the direct current output to the third winding by the direct current source.
3. The method for suppressing dc magnetic bias of a power transformer according to claim 1 or 2, wherein the dc current source is equipped with a communication interface for sending information including a dc current value measured at a neutral point of the primary winding, a dc current value outputted from the dc current source, and an operating state of the dc current source to the monitoring background.
4. The method as claimed in claim 1, wherein the power transformer is a three-phase transformer or a three-phase transformer bank consisting of three single-phase transformers.
5. A method as claimed in claim 1, wherein the three primary windings of the power transformer are connected in a Y-type configuration and the three secondary windings are connected in an △ type configuration.
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| CN201610882024.3A CN106558406B (en) | 2016-10-10 | 2016-10-10 | A kind of suppressing method of power transformer D.C. magnetic biasing |
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| CN201610882024.3A CN106558406B (en) | 2016-10-10 | 2016-10-10 | A kind of suppressing method of power transformer D.C. magnetic biasing |
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| CN106558406A CN106558406A (en) | 2017-04-05 |
| CN106558406B true CN106558406B (en) | 2019-07-09 |
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Families Citing this family (5)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN107507698A (en) * | 2017-08-30 | 2017-12-22 | 杭州钱江电气集团股份有限公司 | A kind of transformer for suppressing function with D.C. magnetic biasing |
| CN110197759A (en) * | 2018-02-26 | 2019-09-03 | 西门子公司 | Transformer, three-phase transformer and its mode of connection |
| CN108400005B (en) * | 2018-04-26 | 2020-12-25 | 湖南大学 | Transformer direct-current magnetic bias suppression system and suppression method |
| CN110632372B (en) * | 2019-08-26 | 2021-08-17 | 深圳供电局有限公司 | Monitoring method for direct current magnetic bias of power transformer |
| CN113391110A (en) * | 2021-06-21 | 2021-09-14 | 陈德才 | Active current transformer capable of resisting direct current component |
Citations (5)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US5499150A (en) * | 1992-05-11 | 1996-03-12 | Matsushita Electric Industrial Co., Ltd. | Magnetic head |
| CN101718852A (en) * | 2009-12-04 | 2010-06-02 | 中国电力科学研究院 | Online detection and calibration method for Hall current sensor |
| CN103824689A (en) * | 2014-03-06 | 2014-05-28 | 山东达驰电气有限公司 | Rectifier transformer adopting series winding |
| CN203720342U (en) * | 2014-03-12 | 2014-07-16 | 国家电网公司 | Direct current magnetic bias automatic compensation device of metering winding of current transformer |
| CN204794020U (en) * | 2015-05-29 | 2015-11-18 | 广西电网有限责任公司电力科学研究院 | Transformer system |
-
2016
- 2016-10-10 CN CN201610882024.3A patent/CN106558406B/en active Active
Patent Citations (5)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US5499150A (en) * | 1992-05-11 | 1996-03-12 | Matsushita Electric Industrial Co., Ltd. | Magnetic head |
| CN101718852A (en) * | 2009-12-04 | 2010-06-02 | 中国电力科学研究院 | Online detection and calibration method for Hall current sensor |
| CN103824689A (en) * | 2014-03-06 | 2014-05-28 | 山东达驰电气有限公司 | Rectifier transformer adopting series winding |
| CN203720342U (en) * | 2014-03-12 | 2014-07-16 | 国家电网公司 | Direct current magnetic bias automatic compensation device of metering winding of current transformer |
| CN204794020U (en) * | 2015-05-29 | 2015-11-18 | 广西电网有限责任公司电力科学研究院 | Transformer system |
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