CN203503452U - Zero-magnetic flux high-accuracy current transformer - Google Patents
Zero-magnetic flux high-accuracy current transformer Download PDFInfo
- Publication number
- CN203503452U CN203503452U CN201320462402.4U CN201320462402U CN203503452U CN 203503452 U CN203503452 U CN 203503452U CN 201320462402 U CN201320462402 U CN 201320462402U CN 203503452 U CN203503452 U CN 203503452U
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- Prior art keywords
- annular core
- winding
- ring
- iron core
- shaped iron
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- Measuring Instrument Details And Bridges, And Automatic Balancing Devices (AREA)
Abstract
The utility model discloses a zero-magnetic flux high-accuracy current transformer which comprises an enclosure, and a ring-shaped iron core T1, a ring-shaped iron core T2, a primary winding, a secondary winding, an additional winding and a compensating resistor Rf which are positioned in the enclosure. The primary winding is sequentially and respectively wound around the ring-shaped iron core T1 and the ring-shaped iron core T2 by turns of N1 or is simultaneously wound around the ring-shaped iron core T1 and the ring-shaped iron core T2 which are mutually overlapped by turns of N1 in total; the secondary winding is sequentially and respectively wound around the ring-shaped iron core T1 and the ring-shaped iron core T2 by coil turns of N2 and N2'; the additional winding is wound around the ring-shaped iron core T2 by turns of N3; the compensating resistor Rf is connected to both ends of the additional winding; the range of N2' is one third of N2 to N2; the range of N3 is one third of N2 to N2; the size of the compensating resistor Rf needs to meet the formula. The zero-magnetic flux high-accuracy current transformer has the advantages that by combining magnet shunt compensation and electric potential compensation, the error level is improved; the ring-shaped iron cores T1 and T2 are small in size and low in cost; a micro potentiometer is used as the compensating resistor Rf, and the accuracy requirement can be flexibly regulated.
Description
Technical field
The utility model relates to a kind of zero magnetic flux high precision current transformer, belongs to instrument transformer field.
Background technology
The ordinary electric current mutual-inductor of using in electrical measurement field, conventionally be all to use single magnetic core, the considerable enamelled wire of coiling thereon, to reach, required the requirement of electric current and precision, especially instrument micro-transformer of current, because its volume is very little, the full accuracy grade that single magnetic core can be accomplished is 0.05 grade at present.
On improve the precision of current transformer, Chinese scholars has proposed the compensation of a lot of bands and not with the kinds of schemes of compensation, some is application to some extent in practice, but current transformer application is very extensive, different occasions is different to its emphasis, but all spectra all can have special requirement to its precision, so improve the accuracy class of instrument transformer, be very important.
Generally have bipolar instrument transformer, the electronic type of application compensate instrument transformer etc. at present, but bipolar instrument transformer has special requirement to two magnetic cores, need two magnetic cores to match, the operating state of these two magnetic cores that just need to be perfectly clear, and the design parameter such as the magnetic permeability under operating state, magnetic flux density, to compensate exactly; And electronic type compensation instrument transformer needs the electronic processing circuit of rear continued access more complicated, very inconvenient concerning Client application side.
Summary of the invention
Technical problem to be solved in the utility model has been to provide the zero magnetic flux high precision current transformer that a kind of certainty of measurement is high, volume is little, cost is low.
The utility model solves the technical scheme that its technical problem adopts:
The utility model comprises casing, is positioned at the annular core T1 of casing, annular core T2, winding, secondary winding, additional winding and a compensating resistance R
f;
A described winding is worn successively around annular core T1, each N of annular core T2
1circle, or wear the N altogether around the annular core T1 being superimposed with each other, annular core T2 simultaneously
1circle; The coil turn that described secondary winding is worn successively around annular core T1, annular core T2 is respectively N
2and N
2'; Described additional winding is worn around annular core T2, and its number of turn is N
3; Described compensating resistance R
fbe connected on additional winding two ends; Described N
2: N
1ratio equal the primary current I by a winding
1with by the secondary current I of secondary winding
2ratio; Described N
2' scope be N
2/ 3 ~ N
2; The scope of described N3 is N
2/ 3 ~ N
2;
Described compensating resistance R
fsize need meet formula
(1),
Wherein, R
bfor being connected on the sampling resistor at the lead-in wire two ends of secondary winding; r
2for secondary winding is worn the internal resistance around annular core T1 part, r
2' wear the internal resistance around annular core T2 part, r for secondary winding
3for additional winding is worn the internal resistance around annular core T2 part.
Described compensating resistance R
ffor miniature potentiometer or fixed value resistance.
The good effect that the utility model produces is as follows: (1) the utility model adopts a kind of magnetic shunt electromotive force compensation way, belong to bipolar instrument transformer, the mode of utilizing electromotive force compensation, the magnetics parameter by various complexity, is converted into simple electromotive force, during to design and use, be very easily, by magnetic shunt compensation and electromotive force compensation, combine, can reach the error requirements of 0.02,0.01,0.005 grade, therefore less demanding to annular core T1, T2, annular core T1, T2 volume are little, and cost is low; (2) adopt miniature potentiometer resistance R by way of compensation
f, can flexible required precision.
Accompanying drawing explanation
Fig. 1 is structure principle chart of the present utility model.
Wherein, empty wire frame representation casing.
Embodiment
Below in conjunction with drawings and Examples, the utility model is further described:
As shown in Figure 1, embodiment 1:
Take specification as 1.5 (6) A/5mA, and error level is that the zero magnetic flux high precision current transformer of 0.01,10 Ω is example;
The present embodiment comprises casing, is positioned at the annular core T1 of casing, annular core T2, winding, secondary winding, additional winding and a compensating resistance R
f;
A described winding is worn the N altogether around annular core T1, annular core T2 simultaneously
1circle; The coil turn that described secondary winding is worn successively around annular core T1, annular core T2 is respectively N
2and N
2'; Described additional winding is worn around annular core T2, and its number of turn is N
3; Described compensating resistance R
fbe connected on additional winding leading-out wire two ends;
Because I
1: I
2=1.5A:5mA=300:1, therefore N
1: N
2=1:300;
N is set
1=4 o'clock, N
2=1200;
N
2' and N
3need to meet and be greater than N
2/ 3, be less than N
2therefore, N
2'=600, N
3=650;
Described compensating resistance R
fsize need meet formula
,
Wherein, R
bfor casing is connected on the sampling resistor at secondary winding lead-in wire two ends outward; r
2for secondary winding is worn the internal resistance around annular core T1 part, r
2' wear the internal resistance around annular core T2 part, r for secondary winding
3for additional winding is worn the internal resistance around annular core T2 part.
One time winding is worn the number of turn N around annular core T1 and annular core T2 simultaneously
1be 4 circles, consistent with each winding impedance on annular core T2 in order to accomplish annular core T1, all selecting specification is the annular core of 14/20 * 5,10mA>=0.15mV, and each winding wire diameter is consistent, is φ 0.15.
Described compensating resistance R
ffor miniature potentiometer.
Embodiment 2:
Take specification as 5 (10) A/5mA, and error level is that the zero magnetic flux high precision current transformer of 0.01,20 Ω is example;
The present embodiment comprises casing, is positioned at the annular core T1 of casing, annular core T2, winding, secondary winding, additional winding and a compensating resistance R
f;
A described winding is worn respectively successively around annular core T1, each N of annular core T2
1circle; The coil turn that described secondary winding is worn successively around annular core T1, annular core T2 is respectively N
2and N
2'; Described additional winding is worn around annular core T2, and its number of turn is N
3; Described compensating resistance R
fbe connected on additional winding leading-out wire two ends;
Because I
1: I
2=5A:5mA=1000:1, therefore N
1: N
2=1:1000;
N is set
1=3 o'clock, N
2=3000;
N
2' and N
3need to meet and be greater than N
2/ 3, be less than N
2therefore, N
2'=1500, N
3=1550;
Described compensating resistance R
fsize need meet formula
,
Wherein, R
bfor casing is connected on the sampling resistor at secondary winding lead-in wire two ends outward;
for secondary winding is worn the internal resistance around annular core T1 part,
for secondary winding is worn the internal resistance around annular core T2 part,
for additional winding is worn the internal resistance around annular core T2 part.
One time winding is worn respectively each 2 circles around annular core T1, annular core T2 successively, consistent with each winding impedance on annular core T2 in order to accomplish annular core T1, all selecting specification is the annular core of 13/17.8 * 5,10mA >=0.13mV, and each winding wire diameter is consistent, be φ 0.13.
Described compensating resistance R
ffor fixed value resistance.
Operation principle of the present utility model is as follows:
1) according to magnetic balance equation:
To annular core, T1 has:
,
exciting current for annular core T1;
To annular core, T2 has:
,
the exciting current of annular core T2;
During use,
,
all be approximately zero, by upper two formulas, we obtain:
N
2：N
1=I
1：I
2
Thereby we determine N by 1. formula
3winding is crossed much electric currents, can carry out coiling with how thick wire.
2) according to R
bthe electromotive force equilibrium equation in loop,
E
2+ E
2'=I
2*(R
b+ r
2+ r
2')-------------------2. formula
3) according to R
fthe electromotive force equilibrium equation in loop,
E
3=I
3* (R
f+ r
3)----------------------------3. formula
Again because N
3on annular core T2, form a miniature transformer with N2 ', have following relation:
------------------------------be formula 4.
Will be 3. formula, 4. 2. formula of formula substitution, can obtain,
Regulate R
f, make
-----------------be formula 5.
Now, E
2=0, i.e. the inner excitation-free current of annular core T1, reaches the object of zero magnetic flux.
1. relational expression above formula substitution, has
Wherein, R
bfor casing is connected on the sampling resistor at secondary winding lead-out wire two ends outward; r
2for secondary winding is worn the internal resistance around annular core T1 part, r
2' wear the internal resistance around annular core T2 part, r for secondary winding
3for additional winding is worn the internal resistance around annular core T2 part.
Work as N
2'=N
3=N
2, there is R at/2 o'clock
f=R
b+ r
2+ r
2'-r
3,
Certainly, N
2', N
3can not be less than N
2/ 3, otherwise annular core T2 is easily saturated; N
2', N
3can not be greater than N
2, otherwise from processing technology difficulty, operability is complicated and can reduce the compensation rate of annular core T1.
When each winding wire diameter is consistent, there is R
f=R
b+ r
2;
When actual production, due to the impact of many factors, each internal resistance tends to there is a little a difference, so compensating resistance R
fcan finely tune with a small-sized potentiometer, or be slightly less than R with one
b+ r
2fixed value resistance.
The high accuracy zero-flux current transformer of magnetic shunt electromotive force compensation, for ordinary electric current mutual-inductor, has following advantage:
(1) ordinary electric current mutual-inductor:
Precision: ordinary electric current mutual-inductor is to use single iron core, the enamelled wire that coiling is thereon very many, conventionally be greater than 1000 circles, a winding is worn around the more number of turn simultaneously, is generally 5 ~ 10 circles, instrument transformer such as 0.05 grade of 1.5 (6) A/5mA, iron core with 16/21 * 10, performance requirement 10mA >=0.45mV, secondary winding 2400 circles, winding 8 circles, just can reach JJG313-2010 to the requirement of 0.05 grade.This iron core is when producing, and very difficult, cost is very high;
Volume: because the current transformer of single iron core is very high to iron core requirement, and will make the iron core that performance is very high, just need to increase the size of iron core, therefore core volume used is larger, and client often wants cube little, and product trend is more and more less;
Volume production: because the desired performance of current transformer of single iron core is very high, qualification rate is very low, so large volume production is infeasible.
(2) current transformer of magnetic shunt electromotive force compensation:
The utility model is as long as adjust compensating resistance R
fmake additional winding N
3by annular core T2, be coupled to secondary winding N
2' part induced potential just in time can reach secondary winding N
2the needed electromotive force of part, current transformer error is approximately zero so, can reach 0.05 grade and above required precision.
Not high to ring-shaped core performance requirement, while reaching same precision, small volume, the iron core of two 14/20 * 5 using in the present embodiment, a little less than the iron core of 16/21 * 10, and around the enamelled wire number of turn to lack a lot, for original 1/2, or the number of turn still less also can reach.
So the zero-flux current transformer of the magnetic shunt electromotive force compensation of employing, compares ordinary electric current mutual-inductor, has incomparable advantage in high-end field.
In sum, be only the utility model preferred embodiment, with this, do not limit the scope that the utility model is implemented, the equivalence of in every case doing according to the content of the utility model claim changes and modifies, all should be as technology category of the present utility model.
Claims (2)
1. a zero magnetic flux high precision current transformer, comprises casing, characterized by further comprising and is positioned at annular core T1, the annular core T2 of casing, winding, secondary winding, additional winding and a compensating resistance R
f;
A described winding is worn successively around annular core T1, each N of annular core T2
1circle, or wear the N altogether around the annular core T1 being superimposed with each other, annular core T2 simultaneously
1circle; The coil turn that described secondary winding is worn successively around annular core T1, annular core T2 is respectively N
2and N
2'; Described additional winding is worn around annular core T2, and its number of turn is N
3; Described compensating resistance R
fbe connected on additional winding two ends; Described N
2: N
1ratio equal the primary current I by a winding
1with by the secondary current I of secondary winding
2ratio; Described N
2' scope be N
2/ 3 ~ N
2; Described N
3scope be N
2/ 3 ~ N
2;
Described compensating resistance R
fsize need meet formula
(1),
Wherein, R
bfor being connected on the sampling resistor at the lead-out wire two ends of secondary winding; r
2for secondary winding is worn the internal resistance around annular core T1 part, r
2' wear the internal resistance around annular core T2 part, r for secondary winding
3for additional winding is worn the internal resistance around annular core T2 part.
2. zero magnetic flux high precision current transformer according to claim 1, is characterized in that described compensating resistance R
ffor miniature potentiometer or fixed value resistance.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201320462402.4U CN203503452U (en) | 2013-07-31 | 2013-07-31 | Zero-magnetic flux high-accuracy current transformer |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201320462402.4U CN203503452U (en) | 2013-07-31 | 2013-07-31 | Zero-magnetic flux high-accuracy current transformer |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CN203503452U true CN203503452U (en) | 2014-03-26 |
Family
ID=50334411
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN201320462402.4U Expired - Fee Related CN203503452U (en) | 2013-07-31 | 2013-07-31 | Zero-magnetic flux high-accuracy current transformer |
Country Status (1)
| Country | Link |
|---|---|
| CN (1) | CN203503452U (en) |
Cited By (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN105304303A (en) * | 2015-09-30 | 2016-02-03 | 中国计量科学研究院 | Precise AC-DC large current transformer |
| CN107424815A (en) * | 2017-08-18 | 2017-12-01 | 陈宇斯 | A kind of two-stage current transformer compensated using circle is subtracted |
| CN112986654A (en) * | 2021-02-10 | 2021-06-18 | 南方电网科学研究院有限责任公司 | Current measuring device of broadband alternating current and direct current |
| CN114280350A (en) * | 2021-12-15 | 2022-04-05 | 浙江巨磁智能技术有限公司 | Large current measuring method based on high-precision current sensor and shunt |
-
2013
- 2013-07-31 CN CN201320462402.4U patent/CN203503452U/en not_active Expired - Fee Related
Cited By (7)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN105304303A (en) * | 2015-09-30 | 2016-02-03 | 中国计量科学研究院 | Precise AC-DC large current transformer |
| CN107424815A (en) * | 2017-08-18 | 2017-12-01 | 陈宇斯 | A kind of two-stage current transformer compensated using circle is subtracted |
| CN107424815B (en) * | 2017-08-18 | 2019-04-30 | 陈宇斯 | A kind of two-stage current transformer compensated using circle is subtracted |
| CN112986654A (en) * | 2021-02-10 | 2021-06-18 | 南方电网科学研究院有限责任公司 | Current measuring device of broadband alternating current and direct current |
| CN112986654B (en) * | 2021-02-10 | 2022-05-03 | 南方电网科学研究院有限责任公司 | Current measuring device of broadband alternating current and direct current |
| CN114280350A (en) * | 2021-12-15 | 2022-04-05 | 浙江巨磁智能技术有限公司 | Large current measuring method based on high-precision current sensor and shunt |
| CN114280350B (en) * | 2021-12-15 | 2024-04-16 | 浙江巨磁智能技术有限公司 | High-precision current sensor and shunt-based high-current measurement method |
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Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| GR01 | Patent grant | ||
| GR01 | Patent grant | ||
| PE01 | Entry into force of the registration of the contract for pledge of patent right |
Denomination of utility model: Zero-flux high-precision current transformer with electricity larceny prevention shielding layer Effective date of registration: 20160531 Granted publication date: 20140326 Pledgee: Bank of China, Limited by Share Ltd, Xinji branch Pledgor: Hebei Shenke Electronics Co., Ltd. Registration number: 2016130000007 |
|
| PLDC | Enforcement, change and cancellation of contracts on pledge of patent right or utility model | ||
| PC01 | Cancellation of the registration of the contract for pledge of patent right | ||
| PC01 | Cancellation of the registration of the contract for pledge of patent right |
Date of cancellation: 20200825 Granted publication date: 20140326 Pledgee: Bank of China, Limited by Share Ltd, Xinji branch Pledgor: HEBEI SHENKE ELECTRONICS Co.,Ltd. Registration number: 2016130000007 |
|
| CF01 | Termination of patent right due to non-payment of annual fee | ||
| CF01 | Termination of patent right due to non-payment of annual fee |
Granted publication date: 20140326 Termination date: 20200731 |