CN204666709U - Half magnetic core current sensor - Google Patents
Half magnetic core current sensor Download PDFInfo
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- CN204666709U CN204666709U CN201520367735.8U CN201520367735U CN204666709U CN 204666709 U CN204666709 U CN 204666709U CN 201520367735 U CN201520367735 U CN 201520367735U CN 204666709 U CN204666709 U CN 204666709U
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- magnetic core
- releasing
- branch road
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- half magnetic
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- RYGMFSIKBFXOCR-UHFFFAOYSA-N Copper Chemical compound [Cu] RYGMFSIKBFXOCR-UHFFFAOYSA-N 0.000 claims abstract description 20
- 229910052802 copper Inorganic materials 0.000 claims abstract description 20
- 239000010949 copper Substances 0.000 claims abstract description 20
- 230000010354 integration Effects 0.000 claims abstract description 14
- 239000003990 capacitor Substances 0.000 claims description 3
- 238000005259 measurement Methods 0.000 abstract description 9
- 230000005389 magnetism Effects 0.000 abstract description 5
- XEEYBQQBJWHFJM-UHFFFAOYSA-N Iron Chemical group [Fe] XEEYBQQBJWHFJM-UHFFFAOYSA-N 0.000 description 9
- 238000005070 sampling Methods 0.000 description 5
- 230000035699 permeability Effects 0.000 description 4
- 230000001052 transient effect Effects 0.000 description 4
- 239000004020 conductor Substances 0.000 description 3
- 238000013461 design Methods 0.000 description 3
- 238000013508 migration Methods 0.000 description 3
- 230000005012 migration Effects 0.000 description 3
- 230000001681 protective effect Effects 0.000 description 3
- 239000000126 substance Substances 0.000 description 3
- 238000006243 chemical reaction Methods 0.000 description 2
- 238000005516 engineering process Methods 0.000 description 2
- 238000004519 manufacturing process Methods 0.000 description 2
- 229920006395 saturated elastomer Polymers 0.000 description 2
- 238000013341 scale-up Methods 0.000 description 2
- 229910000976 Electrical steel Inorganic materials 0.000 description 1
- 230000005355 Hall effect Effects 0.000 description 1
- 206010019133 Hangover Diseases 0.000 description 1
- XUIMIQQOPSSXEZ-UHFFFAOYSA-N Silicon Chemical compound [Si] XUIMIQQOPSSXEZ-UHFFFAOYSA-N 0.000 description 1
- 238000013016 damping Methods 0.000 description 1
- 230000007812 deficiency Effects 0.000 description 1
- 238000011161 development Methods 0.000 description 1
- 238000010586 diagram Methods 0.000 description 1
- 230000007613 environmental effect Effects 0.000 description 1
- 230000005284 excitation Effects 0.000 description 1
- 239000011152 fibreglass Substances 0.000 description 1
- 230000006698 induction Effects 0.000 description 1
- 239000000696 magnetic material Substances 0.000 description 1
- 239000000463 material Substances 0.000 description 1
- 239000011159 matrix material Substances 0.000 description 1
- 238000000034 method Methods 0.000 description 1
- 230000003287 optical effect Effects 0.000 description 1
- 229920000728 polyester Polymers 0.000 description 1
- 229910052710 silicon Inorganic materials 0.000 description 1
- 239000010703 silicon Substances 0.000 description 1
- 229910001220 stainless steel Inorganic materials 0.000 description 1
- 239000010935 stainless steel Substances 0.000 description 1
- 238000012795 verification Methods 0.000 description 1
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Abstract
The utility model belongs to High-Voltage Electrical Appliances field, be specifically related to a kind of half magnetic core current sensor being applied to electronic current mutual inductor, it is characterized in that comprising annular half magnetic core framework, copper coil, integrating resistor, integrating condenser, bleeder resistance and inductance of releasing, magnetic skeleton segment and non magnetic skeleton segment are alternately connected and are tightened to annular half magnetic core framework, annular half magnetic core framework is wound with copper coil, integrating resistor and integrating condenser are connected into integration branch road, two termination integration branch road two ends of copper coil, bleeder resistance is connected into inductance of releasing branch road of releasing, to release two termination integrating condenser two ends of branch road, voltage on integrating condenser is output signal.The utility model does not have the remanent magnetism problem of iron-core coil current transformer, does not have magnetic saturation problem; Compared with hollow coil angular quadrature scheme, size reduces, save copper, improve induced potential to improve small current measurement ability, does not substantially export tailing problem simultaneously.
Description
Technical field
The utility model belongs to High-Voltage Electrical Appliances field, is specifically related to a kind of half magnetic core current sensor being applied to electronic current mutual inductor.
Background technology
Along with the progress of electronic technology, electronic current mutual inductor development in recent years rapidly.Electronic current mutual inductor needs primary current sensor, such as air core coil, iron-core coil, Hall effect element and/or optical devices.
The Appendix D of country proposed standard GB/T 20840.8-2007 " mutual inductor the 8th part: electronic current mutual inductor " discloses two schemes of primary current sensor, one is iron core line ring type low power current transformer (LPCT) scheme, and another is air core coil (Rogowski coil) scheme.
Iron core line ring type low power current transformer (LPCT) scheme is a kind of evolution of traditional electrical magnetic induction principle current transformer, be exactly export termination sampling resistor at the secondary of electromagnetic principle current transformer (CT), voltage on sampling resistor is directly proportional to primary current, is output signal.CT originally will be with sizable load, is on the one hand that the old-fashioned actuating of relay needs certain power to drive, in addition mainly secondary cable very long (from tens meters to upper km), therefore high pressure CT load tens volt-amperes easily, volt-ampere even up to a hundred.In electric mutual inductor, sampling section directly moves on near the secondary coil of CT, and secondary cable becomes very short (several meters even within one meter), therefore significantly can reduce secondary load; Meanwhile, because the output current of CT directly supplies sampling resistor, be the signal of device interior, need not design according to the standard value of original 5A or 1A, a milliampere rank can be designed to, so just more can significantly reduce CT secondary load.The maximum difference of the LPCT after such evolution and traditional CT is that coil output power drops to milliwatt magnitude by tens watts (even going up hectowatt), therefore, under identical core section amasss situation, the measurement range of LPCT electronic current mutual inductor has obvious lifting than traditional CT.LPCT scheme adopts iron core CT to make sensor, and therefore accuracy is high, little by such environmental effects such as temperature, and present electronic current mutual inductor often adopts LPCT scheme to make Verification of Measuring Current Transformer.
Hollow coil scheme utilizes Rogowski coil principle to make primary current sensor.So-called Luo-coil principle is exactly that the voltage of air core coil exports and is directly proportional to the derivative of primary current, therefore the signal that just can obtain being directly proportional to primary current after the output voltage integration of air core coil.Because air core coil does not have magnetic saturation problem, also do not have remanent magnetism problem, dynamic range is wide, and therefore present electronic current mutual inductor often adopts air core coil scheme to make protective current transformer.
Can find out, iron-core coil LPCT scheme and air core coil angular quadrature scheme are diverse two schemes.LPCT scheme adopts transformer principle, can be known by the "T"-shaped equivalent circuit of transformer, primary current (value after amounting to) almost all flows into secondary circuit, and the difference of primary current and secondary current is exactly exciting current, namely the error current of LPCT.Due to the existence of iron core, exciting current proportion is very little, and namely LPCT error is very little, and secondary current is more close to primary current, and error is less.Air core coil angular quadrature scheme is then different, and the output of air core coil is voltage, and namely induced potential deducts internal resistance pressure drop, so the electric current of secondary circuit is less, namely larger with the difference of primary current (after amounting to), error is less.Also can understand from another angle: primary current is almost all for the excitation of air core coil, air core coil two ends are made to produce sufficiently high induced potential, this induced potential drives follow-up integration branch road, with the output voltage of obtain being directly proportional to primary current (instead of being directly proportional to primary current derivative), more big current is less in the impedance of integration branch road, internal resistance pressure drop then in hollow coil is less, and the signal errors finally obtained is less.In view of this reason, point out in national proposed standard GB/T 20840.8-2007, the integral part in air core coil angular quadrature scheme does not generally carry out in coil body, but after move on to relay part.And in reality, normally after A/D conversion, carry out digital integration, be conducive to the load current reducing hollow coil like this, thus reduce hollow coil internal resistance pressure drop, finally reduce measuring error.
In above-mentioned two technical schemes; LPCT scheme making measurement preferably electronic current mutual inductor; air core coil angular quadrature scheme making protection preferably electronic current mutual inductor, also useful LPCT scheme makes the open source information of protection electronic current mutual inductor.Above-mentioned two schemes are all feasible, are currently also all widely used.
But, also exist significantly not enough in technique scheme, mainly:
1, when LPCT scheme is for the protection of mutual inductor, still there is remanent magnetism, saturation problem, although get well a lot than traditional mutual inductor; but for full migration short-circuit current; still easily saturated when C-O-C-O circulation reclosing, cause current measurement errors, cause protective relaying device misoperation.
2, PRACTICE OF DESIGN shows, even if iron-core coil is increased air gap, LPCT scheme is also difficult to meet two conflicting aspects and requires: air gap too little (being less than 0.3%), and saturation problem cannot thoroughly solve; Air gap too large (being greater than 1%), exciting current is too large, and error exceeds standard.
3, air core coil scheme has superiority for Super-Current Measurement, such as the short-circuit current of tens kilo-amperes; But very low for the accuracy of rated current following small current measurement, reason is that the inductance value of hollow coil is less, and induced potential is low.Increase inductance value and will increase the number of turn of copper coil or the sectional area of skeleton, increase cost on the one hand, also greatly increase equipment volume on the other hand, lose a main advantage of electronic mutual inductor.
4, one of air core coil scheme very large shortcoming is the smear that integral element causes, namely after tested electric current disconnects (being zero), the output voltage of mutual inductor can not make zero in time, no matter hardware integration or digital integration, and smear problem is all unresolved at present.Serious smear may cause protective relaying device miscount, causes misoperation.
Utility model content
The purpose of this utility model to overcome the deficiencies in the prior art, a kind of half magnetic core current sensor of utility model, its primary current sensing for electronic current mutual inductor and/or conversion, do not have the remanent magnetism problem of iron-core coil current transformer, do not have magnetic saturation problem; Compared with hollow coil angular quadrature scheme, size reduces, save copper, improve induced potential to improve small current measurement ability, does not substantially export tailing problem simultaneously.
The utility model is achieved by the following technical solution:
I.e. a kind of half magnetic core current sensor, it is characterized in that comprising annular half magnetic core framework, copper coil, integrating resistor, integrating condenser, bleeder resistance and inductance of releasing, magnetic skeleton segment and non magnetic skeleton segment are alternately connected and are tightened to annular half magnetic core framework, annular half magnetic core framework is wound with copper coil, integrating resistor and integrating condenser are connected into integration branch road, two termination integration branch road two ends of copper coil, bleeder resistance is connected into inductance of releasing branch road of releasing, release two termination integrating condenser two ends of branch road, the voltage on integrating condenser is output signal.
As a preferred version of the present utility model: the non-magnetic rate of annular half magnetic core framework is 1% to 70%.
As a preferred version of the present utility model: the resistance of bleeder resistance is not more than the critical resistance value of integrating condenser by branch road electric discharge of releasing.
As a preferred version of the present utility model: integrating resistor value is greater than 10 times of branch impedance value of releasing, branch impedance value of releasing is greater than 10 times of integrating condenser capacitor value.
As a preferred version of the present utility model: inductance of releasing is non-linear core inductance.
First the high relative permeability of magnetic material and the unsaturated characteristic of nonmagnetic substance combine by the utility model, manufacture an equivalent relative permeability μ
ρhigher, not easily magnetically saturated ring skeleton again, the utility model is referred to as half core toroidal skeleton.In this instructions, the ratio that nonmagnetic substance in half core toroidal skeleton accounts for whole ring skeleton girth is called the non-magnetic rate of half magnetic core framework.From traditional CT to have air gap in air gap annular core only to account for about 0.1% ratio different, the non-magnetic rate of half magnetic core framework of the present utility model wants high a lot, is 1% to 70%.In band air-gap iron core CT, if iron core air gap is excessive, measuring error is difficult to meet standard-required; In contrast, if the non-magnetic rate of half magnetic core framework is too small in the utility model, measuring error easily exceeds standard on the contrary, and this causes because the technical solution of the utility model is different from the principle of iron core line ring type mutual inductor scheme.The principle of iron-core coil mutual inductor scheme is: the voltage on sampling resistor is directly proportional to primary current; Principle of the present utility model is: the voltage on integrating condenser is directly proportional to primary current.
After making half core toroidal skeleton, be wound around copper coil thereon, two termination integrating resistor and integrating condensers of copper coil, integrating resistor and integrating condenser are connected into integration branch road, and the voltage on integrating condenser is output signal.In order to solve tailing problem, to release branch road in integrating condenser two termination, a route bleeder resistance of releasing is in series with inductance of releasing.
The utility model has the following advantages compared with existing technical scheme:
1, the remanence coefficient of half core toroidal skeleton is less than 1%, can think substantially without remanent magnetism in engineering reality;
2, with in existing iron core line ring type current transformer same size situation, can ensure that in 250kA full migration transient short circuit current C-O-C-O circulation, half magnetic core framework is unsaturated, this scope covers all possible short-circuit current of current electric system;
3, the nonmagnetic substance of half magnetic core framework does not affect measuring error;
4, several times to tens times is improved than the output voltage of the hollow coil of same size, the same number of turn;
5, copper material (being the part even 1/tens of hollow coil copper consumption) is saved than the hollow coil of same output voltage, same volume;
6, reduce size than the hollow coil of same output voltage, the same number of turn, thus reduce mutual inductor overall dimensions, reduce manufacturing cost.
Accompanying drawing explanation
Fig. 1 is half magnetic core current sensor schematic diagram;
Fig. 2 contrasts with or without the output voltage of branch road of releasing.
As shown in FIG.: 1-magnetic skeleton, 2-non magnetic skeleton, 3-copper coil, R
i-integrating resistor, C-integrating condenser, R
d-bleeder resistance, L-inductance of releasing.
Embodiment
As shown in Figure 1: magnetic skeleton segment 1 is alternately connected with non magnetic skeleton segment 2 and is tightened to annular half magnetic core framework, annular half magnetic core framework is wound with copper coil 3, integrating resistor R
iintegration branch road is connected into, two termination integration branch road two ends of copper coil 3, bleeder resistance R with integrating condenser C
dinductance L is connected into branch road of releasing with releasing, two termination integrating condenser C two ends of branch road of releasing, the voltage u on integrating condenser C
ct () is output signal.Be loaded with tested primary current i
1the conductor of (t) from annular half magnetic core framework through (can single turn conductor, also can multiturn conductor).
In annular half magnetic core framework, the length sum of each section of non magnetic skeleton 2 accounts for the ratio (i.e. non-magnetic rate) of annular half magnetic core framework girth can not be too high or too low, should between 1% to 70%.The equivalent relative permeability μ of annular half magnetic core framework
ρbe roughly the inverse of this ratio, according to the design parameter requirement of mutual inductor, the non-magnetic rate of ring skeleton can be adjusted in above-mentioned scope.
Bleeder resistance R
dresistance should be not more than integrating condenser C by the branch road R that releases
dthe critical resistance value of-L electric discharge:
I.e. R
d-L-C loop should be critical damping or underdamping state.
In addition, also should meet:
R
i>>Z
d>>(ωC)
-1(2)
Here " >> " represents more than at least ten times, Z
dr
dwith the resulting impedance of ω L.Namely: integrating resistor value R
ibe greater than the branch impedance value Z that releases
d10 times, release branch impedance value Z
dbe greater than integrating condenser capacitor value (ω C)
-110 times.Under meeting this condition, owing to increasing the output voltage u that branch road of releasing causes
c(t) and tested current i
1t the phase differential of () is little, can correct or Row sum-equal matrix again after A/D changes in Subsequent electronic circuit.U
cthe amplitude of (t) and tested current i
1t the scale-up factor of the amplitude of () needs to demarcate with standard current transformer, therefore, owing to increasing the output voltage u that branch road of releasing causes
ct the amplitude change of () can be considered, unification is included in the final scale-up factor demarcated.
According to formula (1) and formula (2) selectors parameter, core inductance should be adopted to reduce the size of inductance element when inductance l values of releasing is larger, and the non-linear magnetic core that magnetic permeability should be adopted larger.
Fig. 2 contrasts with or without the output voltage of branch road of releasing.Can find out, suitable bleeder resistance R
dresidual voltage on integrating condenser C can be released by inductance L very soon with releasing, and substantially solves tailing problem.
Embodiment of the present utility model is further illustrated below in conjunction with instantiation.
Half magnetic core ring-like skeleton size Φ 170/ Φ 230-40 (Φ 170 is internal diameter, and Φ 230 is external diameter, and 40 is thickness), magnetic skeleton part adopts cold-reduced silicon sheet, and non magnetic skeleton part adopts fiberglass, non-magnetic rate 10%; Magnetic skeleton segment circularizes with non magnetic skeleton segment is alternately bonding, and fastens with non-magnetic stainless steel band banding.With Φ 0.55 polyester copper wire coiling copper coil 2500 circle on half core toroidal skeleton; All the other component parameters are: R
i=1M Ω, C=1 μ F; R
d=15k Ω, L=120H.The magnetic core of inductance element is silicon steel sheet annular iron core.Rated primary current 1000A, specified accuracy rating is 5TPE, specified symmetrical short-circuit electric current multiple Kssc=30, primary circuit time constant 0.1s, working cycle C (0.11s)-O (0.5s)-C (0.1s)-O, short circuit initial phase angle is 0 (that is: short-circuit current full migration); Rated output voltage 0.0575V.Fig. 2 contrasts with or without the output voltage of branch road of releasing, during t=0.11s, primary current disconnects, if do not release branch road, output voltage is by peak value slow-decay, hangover is serious, to predetermined 0.5s during reclosing (in Fig. 2 0.61s moment), on integrating condenser C, residual voltage is about 1.9V, can not the transient short circuit current (will occur truncation distortion) of correct measurement reclosing; The bleeder resistance R that this concrete embodiment is selected
d=15k Ω, and the residual voltage on integrating condenser (after about 0.07s) can be released less than 1% when about 0.18s by the inductance L=120H that releases, and substantially solves tailing problem.To predetermined Reclosing Instant (i.e. 0.61s moment in Fig. 2), the voltage on integrating condenser C has been 0, can correct measurement short-circuit current.
In rated condition subscript tentering value, if angular difference does not correct, its value is 0.18 °=10.8 ', so during steady-state short-circuit, output voltage amplitude is 0.0575*30*1.414=2.439V, and calculating ratio is 0, and angular difference is 10.8 ', combination misalignment=0.314%, meets standard-required.Under transient state, calculate output voltage peak value 4.6V, peak-peak transient error is 6.2%, meets standard-required.
Claims (5)
1. one and half magnetic core current sensors, it is characterized in that comprising annular half magnetic core framework, copper coil, integrating resistor, integrating condenser, bleeder resistance and inductance of releasing, magnetic skeleton segment and non magnetic skeleton segment are alternately connected and are tightened to annular half magnetic core framework, annular half magnetic core framework is wound with copper coil, integrating resistor and integrating condenser are connected into integration branch road, two termination integration branch road two ends of copper coil, bleeder resistance is connected into inductance of releasing branch road of releasing, release two termination integrating condenser two ends of branch road, the voltage on integrating condenser is output signal.
2. half magnetic core current sensor according to claim 1, is characterized in that the non-magnetic rate of annular half magnetic core framework is 1% to 70%.
3. half magnetic core current sensor as claimed in claim 1, is characterized in that the resistance of bleeder resistance is not more than the critical resistance value of integrating condenser by branch road electric discharge of releasing.
4. half magnetic core current sensor as claimed in claim 1, it is characterized in that integrating resistor value is greater than 10 times of branch impedance value of releasing, branch impedance value of releasing is greater than 10 times of integrating condenser capacitor value.
5. half magnetic core current sensor as claimed in claim 1, the inductance that it is characterized in that releasing is non-linear core inductance.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201520367735.8U CN204666709U (en) | 2015-06-01 | 2015-06-01 | Half magnetic core current sensor |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201520367735.8U CN204666709U (en) | 2015-06-01 | 2015-06-01 | Half magnetic core current sensor |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CN204666709U true CN204666709U (en) | 2015-09-23 |
Family
ID=54137079
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN201520367735.8U Expired - Fee Related CN204666709U (en) | 2015-06-01 | 2015-06-01 | Half magnetic core current sensor |
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| Country | Link |
|---|---|
| CN (1) | CN204666709U (en) |
Cited By (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN104820128A (en) * | 2015-06-01 | 2015-08-05 | 山东辰祥电气设备有限公司 | Semi-magnetic-core current sensor |
| CN108008264A (en) * | 2017-12-04 | 2018-05-08 | 重庆臻远电气有限公司 | Sensor for high voltage electric equipment partial discharge monitoring |
| CN113985106A (en) * | 2021-10-28 | 2022-01-28 | 贵州鑫湄纳米科技有限公司 | Direct current mutual inductance sensor |
-
2015
- 2015-06-01 CN CN201520367735.8U patent/CN204666709U/en not_active Expired - Fee Related
Cited By (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN104820128A (en) * | 2015-06-01 | 2015-08-05 | 山东辰祥电气设备有限公司 | Semi-magnetic-core current sensor |
| CN108008264A (en) * | 2017-12-04 | 2018-05-08 | 重庆臻远电气有限公司 | Sensor for high voltage electric equipment partial discharge monitoring |
| CN113985106A (en) * | 2021-10-28 | 2022-01-28 | 贵州鑫湄纳米科技有限公司 | Direct current mutual inductance sensor |
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Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| C14 | Grant of patent or utility model | ||
| GR01 | Patent grant | ||
| 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: 20150923 |