CN201319315Y - Current transformer - Google Patents
Current transformer Download PDFInfo
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- CN201319315Y CN201319315Y CNU2008202042526U CN200820204252U CN201319315Y CN 201319315 Y CN201319315 Y CN 201319315Y CN U2008202042526 U CNU2008202042526 U CN U2008202042526U CN 200820204252 U CN200820204252 U CN 200820204252U CN 201319315 Y CN201319315 Y CN 201319315Y
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- secondary winding
- current transformer
- resistance
- current
- shielding box
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Abstract
The utility model relates to the field of electronic design and discloses a current transformer. The current transformer comprises an iron core, a secondary winding and a hollow coil, wherein the secondary winding is wound outside the iron core and has the same center as the hollow coil. A leading-in terminal and a leading-out terminal are arranged on the current transformer; the leading-in terminal is communicated with the leading-out terminal by a primary leading wire; and the primary leading wire passes through the centers of the secondary winding and the hollow coil. When external current is led in from the leading-in terminal, flows through the primary leading wire and flows out from the leading-out terminal, the secondary winding generates secondary current by inducing; and the hollow coil generates a voltage signal by inducing. A first shielding box and a second shielding box are respectively arranged outside the secondary winding and the hollow coil, and slots are arranged on the centers of a first electromagnetism shielding box and/or an electromagnetism shielding box. The current transformer has stronger anti-interference performance.
Description
Technical field
The utility model relates to field of electronic design, relates in particular to a kind of current transformer.
Background technology
In electric power system, conventional electromagnetic current transducer is mostly adopted in the measurement of electric current and relaying protection.
There is the insulation system complexity in conventional electromagnetic current transducer; volume is big, and frequency band is narrow, and secondary singal wave distortion when magnetic saturation takes place, measure error are big; protection multiple curve separate unit difference big (interchangeability is poor) causes shortcomings such as protective relaying device misoperation easily.
Simultaneously, along with the extensive use of new technology in electric power system based on microprocessor, make the secondary of conventional electromagnetic current transducer export the current signal that no longer needs 1A or 5A, but tens of mV are to the voltage signal of several V, and therefore conventional electromagnetic current transducer is difficult to satisfy the power system technology requirement.Therefore, the electric current of traditional current transformer output all must convert voltage signal to and just can be defeated by microprocessor, does corresponding intelligent the processing for microprocessor according to voltage signal.
So these shortcomings of traditional electromagnetic current transducer have seriously restricted electric power system to intellectuality, digitlization, networking, device miniaturization, multifunction direction develop.
In addition; for of the interference of less external electromagnetic interference to induction by current; prior art is provided with the electromagnetic shielding box in the coil outside that is used to produce measuring-signal and produce relay protection signal respectively; though this electromagnetic shielding box can shield outside electromagnetic interference; but the introducing of this electromagnetic shielding box can cause the generation of eddy current; produce vertical magnetic field and opposing magnetic field, introduce new disturbing factor, interference free performance is relatively poor
The utility model content
The utility model embodiment provides a kind of current transformer, and its anti-interference is stronger.
The current transformer that the utility model embodiment provides comprises: iron core, secondary winding, air core coil, described secondary winding are wound on outside the described iron core, and described secondary winding is concentric with air core coil;
Be respectively arranged with on described current transformer and insert terminal, pick out terminal, described access terminal, pick out terminal and be connected by a lead, a described lead runs through the center of described secondary winding, air core coil;
When foreign current inserts from inserting terminal, flow through by a described lead, when lead-out terminal flowed out, described secondary winding induction produced secondary current, described air core coil induction generation voltage signal;
Be respectively arranged with first shielding box, secondary shielding box in the outside of described secondary winding, air core coil, the center of described first electromagnetic shielding box and/or electromagnetic shielding box is provided with fluting.
Alternatively, at the two ends of described secondary winding and be connected to resistance.
Alternatively, described resistance is made of at least two resistance wires, and pair twist is together in twos for the resistance wire of described resistance.
Alternatively, described resistance is placed in the described first electromagnetic shielding box.
Alternatively, export by the double layer screen cable at the voltage signal at described resistance two ends.
Alternatively, described iron core adopts the iron-based nano microcrystalline alloy material of high initial magnetic permeability, low-loss, good linearity to make.
Alternatively, outside described iron core, also be provided with the protection box;
Described secondary winding is wound on outside the described iron core, specifically be,
Described secondary winding is wound on outside the described protection box.
Alternatively, described resistance also is electrically connected with merge cells, and the voltage signal at described resistance two ends inputs to digital merge cells, and described digital merge cells converts the voltage signal of described double layer screen cable input to digital signal output.
Alternatively, the output of described digital merge cells also is electrically connected with microprocessor protection equipment, and described microprocessor protection equipment is according to the described current transformer of Digital Signals that inserts.
Alternatively, described resistance adopts the alloy resistance material of high accuracy low-temperature coefficient to make.
Therefore, use the technical scheme of the utility model embodiment, by center fluting is set at the first electromagnetic shielding box or electromagnetic shielding box, can shield outside electromagnetic interference, can also avoid on the first electromagnetic shielding box or the second electromagnetic shielding box because electromagnetic induction forms eddy current, can avoid on the first electromagnetic shielding box or the second electromagnetic shielding box, producing the influence of vertical magnetic field and opposing magnetic field, help improving anti-interference.
Simultaneously on the first electromagnetic shielding box and the second electromagnetic shielding box fluting is set, can avoids producing the influence of vertical magnetic field and opposing magnetic field on the first electromagnetic shielding box and the second electromagnetic shielding box, anti-interference is stronger.
Description of drawings
Accompanying drawing described herein is used to provide further understanding of the present utility model, constitutes the application's a part, does not constitute to improper qualification of the present utility model, in the accompanying drawings:
A kind of current transformer that Fig. 1 provides for the utility model embodiment 1 face structural representation;
The right TV structure schematic diagram of the current transformer of Fig. 1 that Fig. 2 provides for the utility model embodiment 1;
The circuit theory schematic diagram of the current transformer that Fig. 3 provides for the utility model embodiment 1.
Embodiment
Describe the utility model in detail below in conjunction with accompanying drawing and specific embodiment, be used for explaining the utility model in this illustrative examples of the present utility model and explanation, but not as to qualification of the present utility model.
Embodiment 1:
Referring to Fig. 1,2,3, fill in this current transformer by megohmite insulant (such as: the epoxy insulation material), on current transformer, be respectively arranged with and insert terminal, pick out terminal, described access terminal, pick out terminal and be connected by a lead, foreign current (being commonly called as primary current) inserts from inserting terminal, flow through by a lead, when lead-out terminal flows out.
Also be provided with iron core, secondary winding and air core coil in this current transformer, wherein secondary winding is wound on outside the described iron core, the axis coinciding of described secondary winding and air core coil.A lead that is used to conduct foreign current runs through the center of secondary winding, air core coil.
When foreign current inserts from inserting terminal; flow through by a lead; when lead-out terminal flows out; the secondary winding induction produces secondary current (generally being used to measure the usefulness of electric energy); the air core coil induction produces voltage signal and (generally is used to input to relay protection device; electrical network is controlled according to the size (its size is directly proportional with primary current) of voltage for relay protection device, done the usefulness of relaying protection).
In the present embodiment, the coil that is used to produce the relaying protection voltage signal is an air core coil, when this current transformer opens circuit, can not be created in the relaying protection level that air core coil constitutes and produce ferro resonance, helps the stability of relaying protection.And the relaying protection level in traditional current transformer often uses silicon steel sheet to make permeability magnetic material, and the magnetization curve of this property led material has determined that its linearity is bad, the characteristics that the range of linearity is short.
In addition, because different product may use the material of different batches, different magnetization curves causes different saturation points, and interchangeability is bad naturally.
Preferably, air core coil in the present embodiment can also be produced on the printed panel of computer printing, its relevant parameter does not almost change, guarantee each air core coil basically identical of same batch, after the air core coil in some current transformers damages, interchangeability is good naturally, uses convenient.
In addition, the iron core in the present embodiment can adopt the iron-based nano microcrystalline alloy material of high initial magnetic permeability, low-loss, good linearity to make.Adopt this material can on the basis of equal in quality, reduce the volume of iron core, help improving the linearity and precision, it is saturated to be not easy to that electromagnetism takes place, with respect to the silicon steel sheet of the poor linearity of the magnetization curve in traditional current transformer as permeability magnetic material, adopt this material, can make that the output linearity of secondary winding is higher.Experimental results show that: (50A～5000A), the linearity are good to adopt the measuring range of current inductor of this material wide in the present embodiment, precision height (can reach the 0.2S class of accuracy), also unsaturated when heat-stable current, two or three specification current transformers just can cover whole current classes of electrical network, can be used as standard component production and use.
Further, because the iron core that adopts the iron-based nano microcrystalline alloy material of high initial magnetic permeability, low-loss, good linearity to make is comparatively expensive, and volume is little, for it is protected, avoid impaired or influence use owing to collide, one protection box can also be set outside iron core, and secondary winding is wound on outside the described protection box; Rather than directly secondary winding is wound on the iron core.
In the present embodiment; secondary winding (output is used for the signal of electric energy measurement) is arranged with air core coil (output is used for the voltage signal of relaying protection) branch; can satisfy electric power system metering and protection requirement respectively, and the relaying protection level do not have magnetic saturation, volume is little, in light weight.
In the present embodiment, in order to reduce external disturbance, improve the stability of this current transformer, also be respectively arranged with first shielding box, secondary shielding box, and be provided with fluting at the center of the first electromagnetic shielding box or electromagnetic shielding box in the outside of secondary winding, air core coil.
Therefore, use the technical scheme of the utility model embodiment, by center fluting is set at the first electromagnetic shielding box or electromagnetic shielding box, can shield outside electromagnetic interference, can also avoid on the first electromagnetic shielding box or the second electromagnetic shielding box because electromagnetic induction forms eddy current, can avoid on the first electromagnetic shielding box or the second electromagnetic shielding box, producing the influence of vertical magnetic field and opposing magnetic field, help improving anti-interference.
In addition, can also on the first electromagnetic shielding box and the second electromagnetic shielding box, fluting be set simultaneously, can avoid on the first electromagnetic shielding box and the second electromagnetic shielding box, producing the influence of vertical magnetic field and opposing magnetic field, so that the anti-interference of this current transformer is stronger.
In addition, because the electric both sides of output of the prior art are signal current signals (electric current of secondary winding output is directly exported as the electric energy measurement signal) often, when open a way in the output current signal two ends (impedance infinity), can form high pressure, personnel are on every side caused titanic peril, have great safe sequel.In the present embodiment, in order to solve the above problems, can and connect a resistance at the two ends of secondary winding, at the two ends of resistance output voltage signal, because the pressure drop at resistance two ends is directly proportional with the electric current of secondary winding, can reflect electric energy equally, is used for electric energy measurement, can not only realize electric energy measurement like this, and avoid safety problem of the prior art fully.
In addition, in order further to avoid outside electromagnetic interference, resistance also can also be placed in the described first electromagnetic shielding box.
In addition, the lead of the two ends extraction voltage signal of resistance can also be used the double layer screen cable, can further reduce the interference that in transmission course, is subjected to, guarantee the stability and the pure property of power test signal.
In order to prevent that electric current from forming induction by current on resistance, resistive arrangement can be become: resistance is made of at least two resistance wires, pair twist is together in twos for the resistance wire of described resistance, the inductance that makes each resistance wire produce like this offsets, reach inductionless effect, further improve the anti-interference of the power test signal of output.
Along with the extensive use of new technology in electric power system based on microprocessor, make the secondary of conventional electromagnetic current transducer export the current signal that no longer needs 1A or 5A, but tens of mV are to the voltage signal of several V, therefore conventional electromagnetic current transducer is difficult to satisfy the power system technology requirement, as seen these shortcomings of traditional electromagnetic current transducer have seriously restricted electric power system towards intellectuality, digitlization, networking, and device miniaturization, multifunction direction develop.And present embodiment not only can be avoided the be burdened with safety problem of high pressure of aforesaid open circuit at the voltage signal of secondary winding place output resistance as the power test signal; And, can also handle accordingly being used for the corresponding microprocessor of the direct input of power test signal, more can be fit to current technical development and application scenarios.Such as:
This voltage signal can be inputed to digital merge cells (preferably adopting the double layer screen cable), convert digital signal to, be used for the usefulness of digitlization current measurement and real-time microcomputer protective relay by digital merge cells voltage signal as transmission line.
More than technical scheme that the utility model embodiment is provided be described in detail, used specific case herein principle and the execution mode of the utility model embodiment are set forth, the explanation of above embodiment only is applicable to the principle that helps to understand the utility model embodiment; Simultaneously, for one of ordinary skill in the art, according to the utility model embodiment, the part that on embodiment and range of application, all can change, in sum, this description should not be construed as restriction of the present utility model.
Claims (10)
1, a kind of current transformer is characterized in that, comprising: iron core, secondary winding, air core coil, described secondary winding are wound on outside the described iron core, and described secondary winding is concentric with air core coil;
Be respectively arranged with on described current transformer and insert terminal, pick out terminal, described access terminal, pick out terminal and be connected by a lead, a described lead runs through the center of described secondary winding, air core coil;
When foreign current inserts from inserting terminal, flow through by a described lead, when lead-out terminal flowed out, described secondary winding induction produced secondary current, described air core coil induction generation voltage signal;
Be respectively arranged with first shielding box, secondary shielding box in the outside of described secondary winding, air core coil, the center of described first electromagnetic shielding box and/or electromagnetic shielding box is provided with fluting.
2, current transformer according to claim 1 is characterized in that, at the two ends of described secondary winding and be connected to resistance.
3, current transformer according to claim 2 is characterized in that, described resistance is made of at least two resistance wires, and pair twist is together in twos for the resistance wire of described resistance.
According to claim 2 or 3 described current transformers, it is characterized in that 4, described resistance is placed in the described first electromagnetic shielding box.
5, according to claim 2 or 3 described current transformers, it is characterized in that, export by the double layer screen cable at the voltage signal at described resistance two ends.
6, current transformer according to claim 1 and 2 is characterized in that, described iron core adopts the iron-based nano microcrystalline alloy material of high initial magnetic permeability, low-loss, good linearity to make.
7, current transformer according to claim 6 is characterized in that, also is provided with the protection box outside described iron core;
Described secondary winding is wound on outside the described iron core, specifically be,
Described secondary winding is wound on outside the described protection box.
8, current transformer according to claim 1 and 2, it is characterized in that, described resistance also is electrically connected with merge cells, the voltage signal at described resistance two ends inputs to digital merge cells, and described digital merge cells converts the voltage signal of described double layer screen cable input to digital signal output.
9, current transformer according to claim 8 is characterized in that, the output of described digital merge cells also is electrically connected with microprocessor protection equipment, and described microprocessor protection equipment is according to the described current transformer of Digital Signals that inserts.
According to claim 2 or 3 described current transformers, it is characterized in that 10, described resistance adopts the alloy resistance material of high accuracy low-temperature coefficient to make.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CNU2008202042526U CN201319315Y (en) | 2008-11-28 | 2008-11-28 | Current transformer |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CNU2008202042526U CN201319315Y (en) | 2008-11-28 | 2008-11-28 | Current transformer |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CN201319315Y true CN201319315Y (en) | 2009-09-30 |
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| Application Number | Title | Priority Date | Filing Date |
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| CNU2008202042526U Expired - Fee Related CN201319315Y (en) | 2008-11-28 | 2008-11-28 | Current transformer |
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Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN105759101A (en) * | 2016-04-14 | 2016-07-13 | 云南电网有限责任公司电力科学研究院 | Three-phase electronic combined mutual inductor |
-
2008
- 2008-11-28 CN CNU2008202042526U patent/CN201319315Y/en not_active Expired - Fee Related
Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN105759101A (en) * | 2016-04-14 | 2016-07-13 | 云南电网有限责任公司电力科学研究院 | Three-phase electronic combined mutual inductor |
| CN105759101B (en) * | 2016-04-14 | 2019-04-16 | 云南电网有限责任公司电力科学研究院 | A kind of three-phase electronic combination transformer |
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| C14 | Grant of patent or utility model | ||
| GR01 | Patent grant | ||
| C17 | Cessation of patent right | ||
| CF01 | Termination of patent right due to non-payment of annual fee |
Granted publication date: 20090930 Termination date: 20121128 |