CN103050265B - Residual current transformer - Google Patents
Residual current transformer Download PDFInfo
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- CN103050265B CN103050265B CN201210585606.7A CN201210585606A CN103050265B CN 103050265 B CN103050265 B CN 103050265B CN 201210585606 A CN201210585606 A CN 201210585606A CN 103050265 B CN103050265 B CN 103050265B
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Abstract
The present invention discloses a kind of residual current transformer, comprising: core assembly, coil block and shield assembly, and coil block is surrounded on the core assembly outer surface of rectangle; Described coil block comprises testing coil and measuring coil, this measuring coil to be positioned at outside testing coil and to be surrounded on core assembly outer surface, and measuring coil is made up of the left side sub-winding coil be wound around along first direction, the right side sub-winding coil be wound around along second direction, two the upside sub-winding coils be wound around along first direction and second direction respectively, two downside sub-winding coils be wound around along first direction and second direction respectively; The left side sub-winding coil be connected in parallel and right side sub-winding coil are between two the upside sub-winding coils be connected in parallel and two the downside sub-winding coils be connected in parallel.Residual current transformer of the present invention can inhibit the saturation of shield assembly, reduces measure error, improves the reliability of circuit breaker.
Description
Technical field
The present invention relates to field of circuit breakers, be specifically related to a kind of residual current transformer.
Background technology
Residual current transformer common at present uses the ring skeleton and coil with Uniform Electromagnetic Field mostly, and this type of residual current transformer is generally used for the relatively little breaker of plastic casing of current specification.And for frame circuit breaker, because inner space is limited, to consider that when running big current bus produces higher temperature rise, electric insulation and the factor such as easy for installation, frame circuit breaker residual current transformer is generally installed on circuit breaker external and profile is rectangle simultaneously.Traditional residual current transformer be measuring coil equably around on core assembly, as shown in Figure 1.Like this in real work, owing to producing false residual current, breaker controller is caused to sample the residual current of enough large vacation and cause the misoperation of circuit breaker.The factor producing false residual current has several as follows:
(1) one time the position of current－carrying conductor in core window is not placed in the middle or not identical to each back gauge, or secondary winding is skewness on iron core, these all may cause magnetic circuit asymmetric, cause magnetic circuit local saturated, generate false residual current in secondary winding;
(2) due to the restriction of bus installing space, bend more nearby at residual current transformer, the magnetic direction of electric current in bus is changed, when (being such as greater than six times of rated current) when particularly electric current is very large in bus, larger stray magnetic field can be produced near residual current transformer, destroy the symmetry in whole magnetic field, make the magnetic circuit of residual current transformer local saturated, in secondary winding, generate false residual current;
(3) high-current conductor or ferromagnetic material is had all can to produce false residual current near residual current transformer.Because the magnetic field that high-current conductor produces or the magnetic shunt that ferromagnetic material is formed, all can destroy the symmetry in whole magnetic field, thus produce false residual current.
Summary of the invention
The object of the invention is to provide a kind of residual current transformer, and this residual current transformer can suppress the interference shielding stray magnetic field, reduces false residual electricity flow valuve, improves the reliability of circuit breaker work.
For achieving the above object, the technical solution used in the present invention is: a kind of residual current transformer, comprise: core assembly, coil block and shield assembly, coil block is surrounded on the core assembly outer surface of rectangle, described shield assembly comprises balance winding coil and shading ring, core assembly and coil block are positioned at the shielding cavity of shading ring, and balance winding coil is surrounded on shading ring outer surface.
Described coil block comprises testing coil and measuring coil, this measuring coil to be positioned at outside testing coil and to be surrounded on core assembly outer surface, and measuring coil is made up of the left side sub-winding coil be wound around along first direction, the right side sub-winding coil be wound around along second direction, two the upside sub-winding coils be wound around along first direction and second direction respectively, two downside sub-winding coils be wound around along first direction and second direction respectively; The left side sub-winding coil be connected in parallel and right side sub-winding coil are between two the upside sub-winding coils be connected in parallel and two the downside sub-winding coils be connected in parallel; Contact between described two upside sub-winding coils is as output, and the contact between described two downside sub-winding coils is as output.
The technical scheme improved further in technique scheme is as follows:
1, in such scheme, described balance winding coil is by the left hand balance sub-winding coil be connected in parallel and right hand balance sub-winding coil, and this left hand balance sub-winding coil is wound around along second direction, and this right hand balance sub-winding coil is wound around along first direction.
2, in such scheme, described measuring coil each sub-winding loop length is substantially identical.
3, in such scheme, described core assembly protects box and upper cover to form by magnetic core, aluminium alloy, and magnetic core is positioned at the cavity protecting box and upper cover to form by aluminium alloy.
4, in such scheme, described first direction is clockwise direction, and described second direction is counterclockwise; Or described first direction is that counterclockwise described second direction is clockwise direction.
5, in such scheme, the shielding cavity of described shading ring is made up of external shield ring, inner shield ring, lower shading ring and upper shading ring.
Because technique scheme is used, the present invention compared with prior art has following advantages and effect:
Residual current transformer of the present invention reduces external disturbance, and then improves measure error.Measuring coil is divided into substantially identical six sections, as shown in Figure 2.Coil 15 and 16,17 and 18, the 21 and 22 respectively numbers of turn, coiling specification is identical but around on the contrary.Coil 15,17,21 is around to identical.Coil 16,18,22 is around to identical.
In real work, residual current transformer generally can be subject to the interference in contiguous big current magnetic field, as shown in Figure 4.The stray flux that adjacent currents Iw magnetic field produces enters through the A place of residual current transformer, and the outflow of B place, the stray flux Φ 2 in iron core, Φ 2 ' direction are contrary.The stray flux that adjacent currents Iw produces produces the equivalent schematic of induced current IO ' as shown in Figure 5 in measuring coil, three pairs of coils 15 and 16, 17 and 18, 21 and 22 respond to respectively and generate electric current I x and Ix ', Iy and Iy ', Iz and Iz ', due to three pairs of coils number of turn respectively, coiling specification is identical, but around on the contrary, so Ix and Ix ', Iy and Iy ', Iz and Iz ' difference size is substantially equal but direction is contrary, finally obtain IO '=Ix+Ix '=Iy+Iy '=Iz+Iz ' ≈ 0, that is the winding mode of above-mentioned measuring coil can shield the stray flux interference that adjacent currents Iw produces.
Meanwhile, the bus position in real work as shown in Figure 7.When the electric current I 1 in bus, I2 amplitude are very large, very large magnetic field can formed near residual current transformer place, due to the impact of installing space, bus through residual current transformer is bending more nearby apart from residual current transformer, the magnetic direction of electric current in bus is changed, destroy the symmetry in whole magnetic field near residual current transformer, create larger stray magnetic field, stray magnetic field can cause the local of residual current transformer magnetic circuit saturated, secondary coil is made to induce electromotive force, thus produce false residual current, make release misoperation.
In order to avoid above-mentioned situation, increase shading ring 13 outward at residual current transformer, shading ring 13 wraps upper and lower, the interior outside of measuring coil core assembly 10, as shown in Figure 8.When the current value in I1, I2 is very large, the stray magnetic field of generation, due to the shielding action of shading ring, can not cause the local of residual current transformer magnetic circuit saturated, and then produces false residual current.But, as the big current I1 that residual current transformer passes, when the training of I2 supreme Wan An is even higher, the stray magnetic field produced will be very large, on the one hand due to the restriction of residual current transformer installing space, on the other hand due to the consideration (the thicker shield effectiveness of shading ring is better in theory) of cost, therefore the big current I1 that the residual current transformer of limited thickness shading ring is passing is used, when the training of I2 supreme Wan An is even higher, the saturated stray magnetic field shielding that can not will produce completely of shading ring, cause the local of residual current transformer magnetic circuit saturated, and then the residual current producing vacation makes release misoperation.Therefore in order to delay shielding ring filling trend, two groups of balance winding coils 19 and 20 in the outer coiling of shading ring, as shown in Figure 9.The symmetrical coiling of balance winding coil 19 and 20, the number of turn, coiling specification are identical, around on the contrary, are connected in parallel, Compositional balance winding 11.Balance winding 11 and shading ring 13 form shield assembly 14.
Under the interference of stray magnetic field, although balance winding coil 19 is identical with 20 numbers of turn around on the contrary, the electromotive force numerical value equal direction responded in same magnetic field in theory is just in time offset on the contrary, but because stray magnetic field direction is straggly without chapter, the electromotive force causing balance winding coil 19 and 20 to be responded to can not be offset completely, in two groups of coils, induction generates certain electric current, according to Lenz's law, be in the wire meeting induced current in magnetic field, and faradic magnetic field is contrary with the direction in former magnetic field, balance a part of external magnetic potential, also effectively delayed shielding ring filling trend simultaneously, the stray magnetic field of generation masks by shading ring substantially, inner measurement winding is made to produce false residual current from the interference of outside stray magnetic field.In addition, because balance winding coil 19 is identical with 20 numbers of turn around on the contrary, when running into real residual current and I1+I2=Id, balancing, winding coil 19 is contrary with the electromotive force numerical value equal direction of 20 internal inductions offsets completely, therefore generation electric current can not be responded in coil, also would not offset the magnetic field that real residual current produces by induced field, and then the certainty of measurement of winding is measured in impact.
Accompanying drawing explanation
Fig. 1 is prior art measuring coil schematic diagram;
Fig. 2 is measuring coil schematic diagram of the present invention;
Fig. 3 is measuring coil winding equivalent schematic of the present invention;
Fig. 4 is interference schematic diagram;
Fig. 5 is interference equivalent schematic;
Fig. 6 is the residual current transformer schematic diagram of perfect condition;
Fig. 7 is that stray magnetic field produces schematic diagram;
The instrument transformer schematic diagram of Fig. 8 band shading ring
Fig. 9 is the instrument transformer schematic diagram of coiling on radome of the present invention
Figure 10 is the schematic cross-section of instrument transformer of the present invention;
Figure 11 is residual current transformer structural representation of the present invention.
In above accompanying drawing: 1, external shield ring; 2, lower shading ring; 3, inner shield ring; 4, aluminium alloy protection box; 5, magnetic core; 6, upper cover; 7, upper shading ring; 8, measuring coil; 9, testing coil; 10, core assembly; 11, winding coil is balanced; 12, coil block; 13, shading ring; 14, shield assembly; 15, upper left side sub-winding coil; 16, upper right side sub-winding coil; 17, sub-winding coil on the left of side; 18, sub-winding coil on the right side of side; 19, left hand balance sub-winding coil; 20, right hand balance sub-winding coil, 21, lower left side sub-winding coil; 22, lower right side sub-winding coil.
Embodiment
Below in conjunction with drawings and Examples, the invention will be further described:
Embodiment: a kind of residual current transformer, comprise: core assembly 10, coil block 12 and shield assembly 14, coil block 12 is surrounded on core assembly 10 outer surface of rectangle, described shield assembly 14 comprises balance winding coil 11 and shading ring 13, core assembly 10 and coil block 12 are positioned at the shielding cavity of shading ring 13, and balance winding coil 11 is surrounded on shading ring 13 outer surface;
Described coil block 12 comprises testing coil 9 and measuring coil 8, this measuring coil 8 to be positioned at outside testing coil 9 and to be surrounded on core assembly 10 outer surface, and the downside sub-winding coil 18 that the upside sub-winding coil 17, two that measuring coil 8 is wound around along first direction and second direction respectively by the left side sub-winding coil 15 be wound around along first direction, the right side sub-winding coil 16, two that is wound around along second direction is wound around along first direction and second direction respectively forms; The left side sub-winding coil 15 be connected in parallel and right side sub-winding coil 16 are between two the upside sub-winding coils 17 be connected in parallel and two the downside sub-winding coils 18 be connected in parallel; Contact between described two upside sub-winding coils 17 is as upside output, and the contact between described two downside sub-winding coils 18 is as lower side output terminal.
Above-mentioned balance winding coil 11 is made up of the left hand balance sub-winding coil 19 be connected in parallel and right hand balance sub-winding coil 20, and this left hand balance sub-winding coil 19 is wound around along second direction, and this right hand balance sub-winding coil 20 is wound around along first direction.
Above-mentioned first direction is clockwise direction, and described second direction is counterclockwise; Or described first direction is that counterclockwise described second direction is clockwise direction.
As shown in Figure 2.Measuring coil is divided into substantially identical six sections.Coil 15 and 16,17 and 18, the 21 and 22 respectively numbers of turn, coiling specification is identical but around on the contrary, Φ 1 be the magnetic flux of tested residual current Id generation, and L1, L2 are the output of measuring coil, connect sampling resistor.The equivalent schematic of measuring coil as shown in Figure 3.Electric current I O=Ia+Ia '=Ib+Ib '=Ic+Ic ' that tested residual current Id is generated in measuring coil induction by magnetic field induction.L1, L2 two termination sampling resistor during normal measurement, induced current IO flows through sampling resistor and produces voltage drop, for late-class circuit process.When residual current transformer is subject to the interference in contiguous big current Iw magnetic field, as shown in Figure 4, the stray flux that adjacent currents Iw magnetic field produces enters through the A place of residual current transformer, the outflow of B place, and the stray flux Φ 2 in iron core, Φ 2 ' direction are contrary.The stray flux that adjacent currents Iw produces produces the equivalent schematic of induced current IO ' as shown in Figure 5 in measuring coil, three pairs of coils 15 and 16, 17 and 18, 21 and 22 respond to respectively and generate electric current I x and Ix ', Iy and Iy ', Iz and Iz ', due to three pairs of coils number of turn respectively, coiling specification is identical, but around on the contrary, so Ix and Ix ', Iy and Iy ', Iz and Iz ' difference size is substantially equal but direction is contrary, finally obtain IO '=Ix+Ix '=Iy+Iy '=Iz+Iz ' ≈ 0, that is the winding mode of above-mentioned measuring coil can shield the stray flux interference that adjacent currents Iw produces.When actual coiling, because rectangle corner is maximum to the distance at central current Id place, so the magnetic field of corner is the most weak, we generally by the corner coil around closeer mode compensate.
Above-mentioned core assembly 10 protects box 4 and upper cover 6 to form by magnetic core 5, aluminium alloy, and magnetic core 5 is positioned at the cavity protecting box 4 and upper cover 6 to form by aluminium alloy.
The cross section of residual current transformer as Figure 10, shown in residual current transformer structure Figure 11.Magnetic core 5, by being loaded on after certain Technology for Heating Processing in aluminium alloy protection box 4, closes the lid close around, composition core assembly 10 with yellow cured band after 6.First around testing coil 9 on core assembly 10, on testing coil 9 after the yellow cured band of one deck, coiling measuring coil 8, the number of turn of every section and apart from identical, winding is shown in Fig. 2, and the yellow cured band of its external application is close around, composition coil block 12.External shield ring 1, inner shield ring 3, lower shading ring 2 forms shielding cavity, puts into the coil block 12 of band core assembly, then cover shading ring 7 in chamber, close around the cured band of Huang.Outer around balance winding 11 at shading ring, balance winding 11 number of turns is relevant to the measuring coil number of turns, balance winding with flat enamelled wire to meet normally work time winding on electric current≤4A/mm2, balance winding coil short circuit after certain number of turn.
When the current value in I1, I2 is very large, the stray magnetic field of generation, due to the shielding action of shading ring, can not cause the local of residual current transformer magnetic circuit saturated, and then produces false residual current.But, as the big current I1 that residual current transformer passes, when the training of I2 supreme Wan An is even higher, the stray magnetic field produced will be very large, on the one hand due to the restriction of residual current transformer installing space, on the other hand due to the consideration (the thicker shield effectiveness of shading ring is better in theory) of cost, therefore the big current I1 that the residual current transformer of limited thickness shading ring is passing is used, when the training of I2 supreme Wan An is even higher, the saturated stray magnetic field shielding that can not will produce completely of shading ring, cause the local of residual current transformer magnetic circuit saturated, and then the residual current producing vacation makes release misoperation.Therefore in order to delay shielding ring filling trend, two groups of balance winding coils 19 and 20 in the outer coiling of shading ring, as shown in Figure 9.Balance winding coil 19 and 20 symmetrical coiling, the number of turn, coiling specification are identical, around on the contrary, Compositional balance winding 11.Balance winding 11 and shading ring 13 form shield assembly 14.
Under the interference of stray magnetic field, although balance winding coil 19 is identical with 20 numbers of turn around on the contrary, the electromotive force numerical value equal direction responded in same magnetic field in theory is just in time offset on the contrary, but because stray magnetic field direction is straggly without chapter, the electromotive force causing balance winding coil 19 and 20 to be responded to can not be offset completely, in two groups of coils, induction generates certain electric current, according to Lenz's law, be in the wire meeting induced current in magnetic field, and faradic magnetic field is contrary with the direction in former magnetic field, balance a part of external magnetic potential, also effectively delayed shielding ring filling trend simultaneously, the stray magnetic field of generation masks by shading ring substantially, inner measurement winding is made to produce false residual current from the interference of outside stray magnetic field.In addition, because balance winding coil 19 is identical with 20 numbers of turn around on the contrary, when running into real residual current and I1+I2=Id, balancing, winding coil 19 is contrary with the electromotive force numerical value equal direction of 20 internal inductions offsets completely, therefore generation electric current can not be responded in coil, also would not offset the magnetic field that real residual current produces by induced field, and then the certainty of measurement of winding is measured in impact.
Above-described embodiment, only for technical conceive of the present invention and feature are described, its object is to person skilled in the art can be understood content of the present invention and implement according to this, can not limit the scope of the invention with this.All equivalences done according to Spirit Essence of the present invention change or modify, and all should be encompassed in protection scope of the present invention.
Claims (6)
1. a residual current transformer, it is characterized in that: comprising: core assembly (10), coil block (12) and shield assembly (14), coil block (12) is surrounded on core assembly (10) outer surface of rectangle, described shield assembly (14) comprises balance winding coil (11) and shading ring (13), core assembly (10) and coil block (12) are positioned at the shielding cavity of shading ring (13), and balance winding coil (11) is surrounded on shading ring (13) outer surface;
Described coil block (12) comprises measuring coil (8), this measuring coil (8) is surrounded on core assembly (10) outer surface, measuring coil (8) is made up of the left side sub-winding coil (15) be wound around along first direction, the right side sub-winding coil (16) be wound around along second direction, two the upside sub-winding coils (17) be wound around along first direction and second direction respectively, two downside sub-winding coils (18) be wound around along first direction and second direction respectively, and above-mentioned first direction is contrary with second direction; The left side sub-winding coil (15) be connected in parallel and right side sub-winding coil (16) be connected in be connected in parallel two upsides sub-winding coil (17) with two that are connected in parallel on the downside of between sub-winding coil (18); Contact between described two upsides sub-winding coil (17) is as upside output (L1), and the contact between described two downsides sub-winding coil (18) is as lower side output terminal (L2).
2. residual current transformer according to claim 1, it is characterized in that: described balance winding coil (11) is made up of the left hand balance sub-winding coil (19) be connected in parallel and right hand balance sub-winding coil (20), this left hand balance sub-winding coil (19) is wound around along second direction, and this right hand balance sub-winding coil (20) is wound around along first direction.
3. residual current transformer according to claim 1, is characterized in that: described first direction is clockwise direction, and described second direction is counterclockwise; Or described first direction is that counterclockwise described second direction is clockwise direction.
4. residual current transformer according to claim 1 and 2, is characterized in that: described measuring coil (8) each sub-winding loop length is identical.
5. residual current transformer according to claim 1 and 2; it is characterized in that: described core assembly (10) protects box (4) and upper cover (6) to form by magnetic core (5), aluminium alloy, and magnetic core (5) is positioned at the cavity protecting box (4) and upper cover (6) to form by aluminium alloy.
6. residual current transformer according to claim 1 and 2, is characterized in that: the shielding cavity of described shading ring (13) is made up of external shield ring (1), inner shield ring (3), lower shading ring (2) and upper shading ring (7).
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| CN201210585606.7A CN103050265B (en) | 2012-12-31 | 2012-12-31 | Residual current transformer |
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| US9496213B2 (en) | 2015-02-05 | 2016-11-15 | Qualcomm Incorporated | Integrated device package comprising a magnetic core inductor with protective ring embedded in a package substrate |
| CN105353180A (en) * | 2015-12-28 | 2016-02-24 | 武汉磐电科技有限公司 | Strong current generator with multiple uniformly distributed conductors |
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| US11896404B2 (en) | 2019-12-31 | 2024-02-13 | Shanghai United Imaging Healthcare Co., Ltd. | Systems and methods for medical imaging of a heart and analysis of ECG target channel |
| CN111856192A (en) * | 2020-07-31 | 2020-10-30 | 深圳市德恒科技有限公司 | No load check out test set |
| CN113466526B (en) * | 2021-07-27 | 2022-07-26 | 河北工业大学 | Residual current sensor circuit and circuit breaker |
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| JP2711308B2 (en) * | 1991-07-16 | 1998-02-10 | ミドリ安全株式会社 | Zero-phase current transformer |
| JPH05159952A (en) * | 1991-12-05 | 1993-06-25 | Toshiba Corp | Zero-phase current transformer and winding method therefor |
| CN201340797Y (en) * | 2009-02-13 | 2009-11-04 | 保定天威集团有限公司 | Large current transformer used for generator outlet |
| CN201877277U (en) * | 2010-12-06 | 2011-06-22 | 保定天威集团有限公司 | Secondary winding structure for local magnetic biasing prevention current transformer |
| CN202230862U (en) * | 2011-08-23 | 2012-05-23 | 常熟开关制造有限公司(原常熟开关厂） | After-current transformer |
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| CN203103107U (en) * | 2012-12-31 | 2013-07-31 | 常熟开关制造有限公司(原常熟开关厂） | After-current transformer |
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