CN110783076B - High-precision current transformer - Google Patents
High-precision current transformer Download PDFInfo
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- CN110783076B CN110783076B CN201911043687.6A CN201911043687A CN110783076B CN 110783076 B CN110783076 B CN 110783076B CN 201911043687 A CN201911043687 A CN 201911043687A CN 110783076 B CN110783076 B CN 110783076B
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- 238000004804 winding Methods 0.000 claims abstract description 136
- XEEYBQQBJWHFJM-UHFFFAOYSA-N Iron Chemical group [Fe] XEEYBQQBJWHFJM-UHFFFAOYSA-N 0.000 claims description 25
- WABPQHHGFIMREM-UHFFFAOYSA-N lead(0) Chemical compound [Pb] WABPQHHGFIMREM-UHFFFAOYSA-N 0.000 claims description 6
- 238000005259 measurement Methods 0.000 abstract description 2
- 238000003780 insertion Methods 0.000 description 8
- 230000037431 insertion Effects 0.000 description 8
- 238000010586 diagram Methods 0.000 description 5
- 238000005457 optimization Methods 0.000 description 5
- 238000001514 detection method Methods 0.000 description 4
- 238000012986 modification Methods 0.000 description 2
- 230000004048 modification Effects 0.000 description 2
- 229920006395 saturated elastomer Polymers 0.000 description 2
- 230000006978 adaptation Effects 0.000 description 1
- 230000009286 beneficial effect Effects 0.000 description 1
- 239000012141 concentrate Substances 0.000 description 1
- 230000020169 heat generation Effects 0.000 description 1
- 238000013021 overheating Methods 0.000 description 1
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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
- H01F27/28—Coils; Windings; Conductive connections
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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
- H01F27/24—Magnetic cores
- H01F27/26—Fastening parts of the core together; Fastening or mounting the core on casing or support
- H01F27/263—Fastening parts of the core together
-
- 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
- H01F27/28—Coils; Windings; Conductive connections
- H01F27/2895—Windings disposed upon ring cores
-
- 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
-
- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01F—MAGNETS; INDUCTANCES; TRANSFORMERS; SELECTION OF MATERIALS FOR THEIR MAGNETIC PROPERTIES
- H01F38/00—Adaptations of transformers or inductances for specific applications or functions
- H01F38/20—Instruments transformers
- H01F38/22—Instruments transformers for single phase AC
- H01F38/28—Current transformers
- H01F38/30—Constructions
-
- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01F—MAGNETS; INDUCTANCES; TRANSFORMERS; SELECTION OF MATERIALS FOR THEIR MAGNETIC PROPERTIES
- H01F38/00—Adaptations of transformers or inductances for specific applications or functions
- H01F38/20—Instruments transformers
- H01F38/22—Instruments transformers for single phase AC
- H01F38/28—Current transformers
- H01F38/30—Constructions
- H01F2038/305—Constructions with toroidal magnetic core
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- Engineering & Computer Science (AREA)
- Power Engineering (AREA)
- Transformers For Measuring Instruments (AREA)
Abstract
The invention relates to a high-precision current transformer, which comprises a primary winding and a plurality of secondary windings, wherein the primary winding and the plurality of secondary windings form a plurality of winding units, each winding unit comprises a secondary winding, and the plurality of secondary windings are connected in series or disconnected through a circuit breaker; two ends of the primary winding are respectively connected with two bus incoming line ends; the invention is suitable for measurement with larger current range span, the series-connected secondary windings are gradually increased according to the increase of actual current, and the turn ratio is correspondingly improved, so that the secondary current is in a proper range, cannot be too small, cannot cause full load, and is worth popularizing.
Description
Technical Field
The invention belongs to the technical field of transformers, and particularly relates to a high-precision current transformer.
Background
The mutual inductor is also called instrument transformer, and is a general name of current mutual inductor and voltage mutual inductor. The high voltage can be changed into low voltage, and the large current can be changed into small current for measuring or protecting the system. Its function is mainly to convert high voltage or large current into standard low voltage (100V) or standard small current (5A or 1A, both referring to rated value) in proportion so as to realize standardization and miniaturization of measuring instrument, protection equipment and automatic control equipment. Meanwhile, the mutual inductor can be used for isolating a high-voltage system so as to ensure the safety of people and equipment.
Because the current variation range is large, the secondary winding and the primary winding are required to have a large turn ratio suitable for a current peak value, but the current value at a measuring end is small after the secondary current is reduced by a large multiplying factor when the current valley value is or is close to the valley value, so that the measuring accuracy is small, and if the turn ratio is small, although the measuring accuracy can be improved, the rated primary current cannot reach the current peak value, so that the problems of unsatisfied measuring range and full-load overheating are caused.
Disclosure of Invention
An object of the present invention is to solve the above problems and to provide a high-precision current transformer capable of accurately measuring a current in a wide range.
The invention realizes the purpose through the following technical scheme:
the high-precision current transformer comprises a primary winding and a plurality of secondary windings, wherein the primary winding and the plurality of secondary windings form a plurality of winding units, each winding unit comprises one secondary winding, and the plurality of secondary windings are connected in series or disconnected through a circuit breaker.
As a further optimized scheme of the invention, the plurality of secondary windings are respectively wound on the iron cores, the number of the iron cores is the same as that of the secondary windings, and the primary windings are wound on the plurality of iron cores; each secondary winding is provided with two wire outlet ends which are a first wire outlet end and a second wire outlet end respectively;
the first wire outlet end of one secondary winding and the second wire outlet end of the other secondary winding in two adjacent secondary windings are connected with the movable end of the circuit breaker together, and the immovable end of the short-circuit switch is connected with the concentrated lead;
the first wire outlet ends of the other secondary windings except the first secondary winding in the secondary windings are provided with short-circuit switches, the movable ends of the short-circuit switches are connected with the secondary windings, the other two immobile ends of the short-circuit switches are respectively connected with a short-circuit line and a switch connecting line, the other end of the short-circuit line is connected with the second wire outlet end, and the other end of the switch connecting line is connected with the movable end of the short-circuit switch;
the first wire outlet end of the first secondary winding in the secondary windings is connected with the first main wire outlet end, the second wire outlet end of the last secondary winding is connected with the concentrated lead wire, and the concentrated lead wire is connected with the second main wire outlet end. The first main outgoing line end and the second main outgoing line end are connected with a current detection module for detecting output current.
The line outlet ends of the secondary windings are connected end to form a series structure, the series connection is disconnected under the control of the circuit breaker, and the disconnected secondary windings are connected to a short circuit line through the short circuit switch to form a short circuit.
As a further optimization scheme of the invention, two ends of the primary winding are respectively connected with two bus incoming line ends.
As a further optimization of the present invention, the number of turns of the plurality of secondary windings is gradually increased from the first to the last.
As a further optimization scheme of the invention, the short-circuit switch is normally closed with the short-circuit line and is normally open with the switch connecting line.
As a further preferred embodiment of the invention, the circuit breaker is normally closed.
As a further optimization scheme of the invention, the short-circuit switch and the circuit breaker are both temperature switches, and the short-circuit switch and the circuit breaker connected with the secondary winding are attached to the iron core on the other side of the secondary winding. This is because the heat is concentrated in the portion of the core around which the primary winding is wrapped. The temperature switch is used as a switch element and can directly correspond to the temperature of the iron core, and the mechanical switch structure is high in stability and free from the influence of a magnetic field.
As a further optimized scheme of the invention, the iron core is annular and comprises six annular bodies with triangular cross sections, the annular bodies are spliced to form a structure with a circular cross section, the annular bodies are divided into two parts which are symmetrically arranged, the two parts of the annular bodies are spliced, the two parts of the annular bodies are respectively a first annular body and a second annular body, one ends of the first annular body and one end of the second annular body are provided with jacks, the other ends of the first annular body and the second annular body are provided with plugs matched with the jacks, when the first annular body and the second annular body are spliced, the plug of the first annular body is inserted into the jack of the second annular body, the plug of the second annular body is inserted into the jack of the first annular body, and the two annular bodies are sequentially connected end to form a closed annular structure.
As a further optimization scheme of the invention, a main end switch is arranged between the first outlet end of the first secondary winding of the plurality of secondary windings and the secondary windings, the movable end of the main end switch is connected with the secondary windings, the immovable end of the main end switch is connected with a short-circuit line, and the other end of the short-circuit line is connected with the second outlet end of the secondary windings. And the main end switch is used for short-circuiting the head-end secondary winding, so that the whole secondary winding is disconnected from the detection module. As a safety guarantee measure, the high-voltage hazard caused by complete open circuit of the secondary winding is avoided.
The invention has the beneficial effects that:
1) the invention is suitable for measurement with larger current range span, the secondary windings which are connected in series are gradually increased according to the increase of the actual current, and the turn ratio is correspondingly improved, so that the secondary current is in a proper range and cannot be too small or cause full load;
2) the invention adopts a combined iron core structure, and is convenient to assemble.
Drawings
FIG. 1 is a schematic structural diagram of the present invention in accordance with one embodiment;
FIG. 2 is a schematic diagram of the primary winding of the present invention according to one embodiment;
FIG. 3 is a schematic diagram of a secondary winding according to the present invention in one embodiment;
fig. 4 is a schematic structural diagram of a core according to the first embodiment of the present invention;
fig. 5 is a schematic cross-sectional view of a core according to the first embodiment of the present invention;
FIG. 6 is a schematic end view of a ring body according to one embodiment of the present invention;
fig. 7 is a schematic structural diagram of the present invention in the second embodiment.
In the figure: the transformer comprises a primary winding 1, a secondary winding 2, an iron core 3, a first wire outlet end S1, a second wire outlet end S2, a short-circuit switch K1, a circuit breaker K2, a main end switch K3, a ring body 10, a jack 11 and a plug 12.
Detailed Description
The present application will now be described in further detail with reference to the drawings, it should be noted that the following detailed description is given for illustrative purposes only and is not to be construed as limiting the scope of the present application, as those skilled in the art will be able to make numerous insubstantial modifications and adaptations to the present application based on the above disclosure.
Example one
As shown in fig. 1-6, the high-precision current transformer includes a primary winding 1 and a plurality of secondary windings 2, the primary winding 1 and the plurality of secondary windings 2 form a plurality of winding units, each winding unit includes a secondary winding 2, and the plurality of secondary windings 2 are connected in series or disconnected through a circuit breaker K2.
The secondary windings 2 are wound on the iron cores 3 respectively, the number of the iron cores 3 is the same as that of the secondary windings 2, and the primary windings 1 are wound on the iron cores 3.
Each secondary winding 2 is provided with two wire outlet ends, namely a first wire outlet end S1 and a second wire outlet end S2;
a first wire outlet end S1 of one secondary winding 2 in two adjacent secondary windings 2 and a second wire outlet end S2 of the other secondary winding 2 are connected with a movable end of a circuit breaker K2 together, and a fixed end of a short-circuit switch K1 is connected with a concentrated lead;
the first wire outlet ends S1 of the other secondary windings 2 except the first secondary winding 2 in the secondary windings 2 are respectively provided with a short-circuit switch K1, the movable end of the short-circuit switch K1 is connected with the secondary windings 2, the other two immobile ends are respectively connected with a short-circuit line and a switch connecting line, the other end of the short-circuit line is connected with the second wire outlet end S2, and the other end of the switch connecting line is connected with the movable end of the short-circuit switch K1;
the first outlet end S1 of the first secondary winding 2 of the plurality of secondary windings 2 is connected to the first main outlet end, the second outlet end S2 of the last secondary winding 2 is connected to the concentrated lead wire, and the concentrated lead wire is connected to the second main outlet end. The first main outgoing line end and the second main outgoing line end are connected with a current detection module for detecting output current.
The outlet ends of the secondary windings 2 are connected end to form a series structure, the disconnection of the series connection is controlled by a circuit breaker K2, and the disconnected secondary windings 2 are connected to a short circuit line by a short circuit switch K1 to form a short circuit.
Preferably, two ends of the primary winding 1 are respectively connected with two bus incoming terminals.
Preferably, the number of turns of the plurality of secondary windings 2 is gradually increased from the first to the last.
Preferably, the short-circuit switch K1 is normally closed to the short-circuit line and normally open to the switch line.
Preferably, the cut-off switch K2 is normally closed.
Preferably, the short-circuit switch K1 and the cut-off switch K2 are both temperature switches, and the short-circuit switch K1 and the cut-off switch K2 connected to the secondary winding 2 are attached to the iron core 3 on the other side of the secondary winding 2. This is because the heat generation is concentrated on the portion of the core 3 around which the primary winding 1 is wrapped. The temperature switch can directly correspond to the temperature of the iron core 3 as a switching element, and the mechanical switch structure has high stability and is not influenced by a magnetic field.
According to the working principle of the invention, under a normal state, a plurality of secondary windings 2 are disconnected and independent, the tail-end secondary winding 2 is connected with a measuring circuit, if the current is too large, the iron core is saturated and heated, the next secondary winding 2 is connected with the tail-end secondary winding 2 to form an integral winding, the number of turns of the integral winding is increased, and the multiplying power and the load are improved.
If the iron core 3 is saturated and still cannot be relieved, the secondary winding 2 is connected with the next secondary winding 2, the number of turns of the whole winding is increased again, the multiplying power and the load are improved until the secondary windings 2 are connected in series, and the whole winding with the number of turns equal to the sum of the secondary windings 2 is formed.
The iron core 3 is annular, including six ring bodies 10 that the cross section is the triangle-shaped, the ring body 10 concatenation constitutes the cross-section and is circular structure, this ring body 10 divides into the two parts that the symmetry set up, peg graft between the two parts ring body 10, two parts ring body 10 are first ring body and second ring body respectively, the one end of first ring body and second ring body is equipped with jack 11, the other end is equipped with plug 12 with jack 11 complex, plug 12 of first ring body inserts in the jack 11 of second ring body when first ring body splices with the second ring body, plug 12 of second ring body inserts in the jack 11 of first ring body, the two connects gradually end to end constitutes closed ring structure.
Preferably, three insertion holes 11 are formed in the end face of the first annular body, the three insertion holes 11 are distributed in a delta shape, the three insertion holes 11 are separated by T-shaped ribs, and a plug 12 matched with the three insertion holes 11 is arranged on the other end face of the first annular body. The connection strength can be effectively maintained.
Preferably, three insertion holes 11 are formed in the end face of the second annular body, the three insertion holes 11 are distributed in a delta shape, the three insertion holes 11 are separated by T-shaped ribs, and a plug 12 matched with the three insertion holes 11 is arranged on the other end face of the second annular body.
Preferably, an insulating layer is arranged between the annular bodies. The contact resistance is reduced.
Preferably, the joints of the first annular bodies and the second annular bodies of the iron core 3 are distributed in a staggered manner. Avoid the seam to concentrate, avoid the concentration of seam magnetic resistance, reduce the whole magnetic resistance of combination formula iron core.
For the combination of the combined iron core 3, the first annular bodies of a plurality of combination units are spliced to form an unclosed annular structure, the second annular bodies of a plurality of combination units are spliced to form an unclosed annular structure, and the primary winding 1 and the secondary winding 2 are wound after the unclosed annular structure is formed by the closed annular structures formed by splicing the first annular bodies and the second annular bodies.
And then splicing the closed annular structure formed by splicing the first annular body and the unclosed annular structure formed by the second annular body to form an annular structure.
Preferably, the iron cores 3 are supported and positioned by an insulating framework.
Example two
As shown in fig. 7, in the first embodiment, a main end switch K3 is provided between the first outlet end S1 of the first secondary winding 2 of the plurality of secondary windings 2 and the secondary winding 2, a moving end of the main end switch K3 is connected to the secondary winding 2, a stationary end is connected to a short-circuit line, and the other end of the short-circuit line is connected to the second outlet end S2 of the secondary winding 2. The main end switch K3 short-circuits the head end secondary winding 2, disconnecting the entire secondary winding 2 from the detection module. As a safety guarantee measure, the high-voltage hazard caused by the complete open circuit of the secondary winding 2 is avoided.
The above-mentioned embodiments only express several embodiments of the present invention, and the description thereof is more specific and detailed, but not construed as limiting the scope of the present invention. It should be noted that, for a person skilled in the art, several variations and modifications can be made without departing from the inventive concept, which falls within the scope of the present invention.
Claims (6)
1. High accuracy current transformer, its characterized in that: the transformer comprises a primary winding and a plurality of secondary windings, wherein the primary winding and the plurality of secondary windings form a plurality of winding units, each winding unit comprises one secondary winding, and the plurality of secondary windings are connected in series or disconnected through a circuit breaker;
the secondary windings are wound on the iron cores respectively, the number of the iron cores is the same as that of the secondary windings, and the primary windings are wound on the iron cores; each secondary winding is provided with two wire outlet ends which are a first wire outlet end and a second wire outlet end respectively;
the first wire outlet end of one secondary winding and the second wire outlet end of the other secondary winding in two adjacent secondary windings are connected with the movable end of the circuit breaker together, and the immovable end of the short-circuit switch is connected with the concentrated lead;
the first wire outlet ends of the other secondary windings except the first secondary winding in the secondary windings are provided with short-circuit switches, the movable ends of the short-circuit switches are connected with the secondary windings, the other two immobile ends of the short-circuit switches are respectively connected with a short-circuit line and a switch connecting line, the other end of the short-circuit line is connected with the second wire outlet end, and the other end of the switch connecting line is connected with the movable end of the short-circuit switch;
a first outgoing line end of a first secondary winding in the secondary windings is connected with a first main outgoing line end, a second outgoing line end of a last secondary winding is connected with a concentrated lead wire, and the concentrated lead wire is connected with a second main outgoing line end;
the iron core is annular and comprises six annular bodies with triangular cross sections, the annular bodies are spliced to form a structure with a circular cross section, each annular body is divided into two parts which are symmetrically arranged, the annular bodies of the two parts are spliced, the annular bodies of the two parts are respectively a first annular body and a second annular body, one ends of the first annular body and one end of the second annular body are provided with jacks, the other ends of the first annular body and the second annular body are provided with plugs matched with the jacks, when the first annular body and the second annular body are spliced, the plug of the first annular body is inserted into the jack of the second annular body, the plug of the second annular body is inserted into the jack of the first annular body, and the first annular body and the second annular body are sequentially connected end to form a closed annular structure;
the number of turns of the secondary windings is gradually increased from the first to the last.
2. The high precision current transformer of claim 1, wherein: and two ends of the primary winding are respectively connected with two bus incoming line ends.
3. The high precision current transformer of claim 1, wherein: the short-circuit switch is normally closed with the short-circuit line and normally open with the switch connecting line.
4. The high precision current transformer of claim 1, wherein: the circuit breaker is normally closed.
5. The high precision current transformer of claim 1, wherein: the short-circuit switch and the circuit breaking switch are both temperature switches, and the short-circuit switch and the circuit breaking switch connected with the secondary winding are attached to the iron core on the other side of the secondary winding.
6. The high precision current transformer of claim 1, wherein: a main end switch is arranged between a first wire outlet end of a first secondary winding of the secondary windings and the secondary windings, a movable end of the main end switch is connected with the secondary windings, a fixed end of the main end switch is connected with a short-circuit line, and the other end of the short-circuit line is connected with a second wire outlet end of the secondary windings.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201911043687.6A CN110783076B (en) | 2019-10-30 | 2019-10-30 | High-precision current transformer |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201911043687.6A CN110783076B (en) | 2019-10-30 | 2019-10-30 | High-precision current transformer |
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| Publication Number | Publication Date |
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| CN110783076A CN110783076A (en) | 2020-02-11 |
| CN110783076B true CN110783076B (en) | 2022-04-05 |
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| Application Number | Title | Priority Date | Filing Date |
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| CN201911043687.6A Active CN110783076B (en) | 2019-10-30 | 2019-10-30 | High-precision current transformer |
Country Status (1)
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Family Cites Families (11)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| FR1011150A (en) * | 1948-12-14 | 1952-06-19 | All voltage test transformer | |
| JPS5530875A (en) * | 1978-08-28 | 1980-03-04 | Fuji Electric Co Ltd | Multiple ratio current transformer |
| JP3286446B2 (en) * | 1993-12-29 | 2002-05-27 | 住友特殊金属株式会社 | DC current sensor |
| CN201540814U (en) * | 2009-09-30 | 2010-08-04 | 淄博元星电子有限公司 | Transient current transformer |
| CN101996763B (en) * | 2010-10-14 | 2011-12-28 | 北京四方继保自动化股份有限公司 | Current mutual inductor and current transformer for protecting frequency-adjusting electromotor |
| CN201887715U (en) * | 2010-11-15 | 2011-06-29 | 山东泰开互感器有限公司 | Voltage transformer error regulating device |
| CN106486260A (en) * | 2015-08-31 | 2017-03-08 | 江苏启源雷宇电气科技有限公司 | A kind of reduction series resonance reactor noise mechanism |
| CN205789476U (en) * | 2016-05-19 | 2016-12-07 | 中国电力科学研究院 | Current transformer |
| CN106298214B (en) * | 2016-09-23 | 2018-01-09 | 国网江西省电力公司电力科学研究院 | A kind of wide-range Zero flux current ratio converter |
| US10491130B2 (en) * | 2017-12-21 | 2019-11-26 | Hamilton Sundstrand Corporation | Multi-purpose power conversion module |
| CN108597827A (en) * | 2018-04-13 | 2018-09-28 | 华建电气有限公司 | V-type face Open Type Electric Current Mutual Inductor and its production technology |
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2019
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