CN1029494C - AC/DC current comparator - Google Patents
AC/DC current comparator Download PDFInfo
- Publication number
- CN1029494C CN1029494C CN 92103969 CN92103969A CN1029494C CN 1029494 C CN1029494 C CN 1029494C CN 92103969 CN92103969 CN 92103969 CN 92103969 A CN92103969 A CN 92103969A CN 1029494 C CN1029494 C CN 1029494C
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- winding
- current
- iron core
- measuring head
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- 238000004804 winding Methods 0.000 claims abstract description 23
- 239000003990 capacitor Substances 0.000 claims abstract description 4
- XEEYBQQBJWHFJM-UHFFFAOYSA-N Iron Chemical group [Fe] XEEYBQQBJWHFJM-UHFFFAOYSA-N 0.000 claims description 17
- 238000012216 screening Methods 0.000 claims description 4
- 238000012544 monitoring process Methods 0.000 claims description 3
- 239000003822 epoxy resin Substances 0.000 claims description 2
- 229920000647 polyepoxide Polymers 0.000 claims description 2
- 238000010125 resin casting Methods 0.000 claims description 2
- 238000012360 testing method Methods 0.000 abstract description 7
- 230000008878 coupling Effects 0.000 abstract 1
- 238000010168 coupling process Methods 0.000 abstract 1
- 238000005859 coupling reaction Methods 0.000 abstract 1
- 230000000694 effects Effects 0.000 description 4
- 238000010586 diagram Methods 0.000 description 3
- 239000000463 material Substances 0.000 description 3
- 230000005415 magnetization Effects 0.000 description 2
- 230000035699 permeability Effects 0.000 description 2
- 229910002070 thin film alloy Inorganic materials 0.000 description 2
- 229910000976 Electrical steel Inorganic materials 0.000 description 1
- 238000013459 approach Methods 0.000 description 1
- 238000001514 detection method Methods 0.000 description 1
- 230000005284 excitation Effects 0.000 description 1
- 238000001914 filtration Methods 0.000 description 1
- 230000008676 import Effects 0.000 description 1
- 238000004519 manufacturing process Methods 0.000 description 1
- 238000005259 measurement Methods 0.000 description 1
- 239000000203 mixture Substances 0.000 description 1
- 238000006386 neutralization reaction Methods 0.000 description 1
- 230000001737 promoting effect Effects 0.000 description 1
- 230000035939 shock Effects 0.000 description 1
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- Measuring Instrument Details And Bridges, And Automatic Balancing Devices (AREA)
- Measurement Of Current Or Voltage (AREA)
Abstract
The invention belongs to a current testing device, which is a comparator and consists of a measuring head and an electronic amplifier, wherein the measuring head is in an annular opening shape and consists of an upper half ring and a lower half ring, and a half surface A and a half surface B are arranged in the diameter direction. The mutual inductance direct coupling circuit of the secondary alternating current in the electronic amplifier is composed of a secondary winding, a load resistor, an electrolytic capacitor and a diode. The device can measure direct current and alternating current, and can also measure alternating current and direct current simultaneously, the assembly and disassembly are very convenient in field test, and the power failure, the assembly and the disassembly of the tested bus and the assembly and the disassembly of the tested mutual inductor are avoided.
Description
The invention belongs to current testing device, be particularly suitable for alternating current-direct current mixing use occasion.
Device and the circuit of " electronics engineers journal, electronics and power " (Electronics and Power The Journal of the Institution of Electrical Engineers Vol.32 No.1 January 1977.) published article " accurately measuring direct current and alternating current " (Accurate Measurement of d.c.and a.c.by Transformer) with mutual inductor.Though this comparator is very attractive, have following two shortcomings at least: the measuring head of (one) this comparator is a kind of closed loop structure, must be passed from the closed loop center by survey line, and test is very inconvenient to industry spot for this.The employed material of measuring head is the high permeability thin film alloys, costs an arm and a leg.Ability to bear to electromagnetism, physical shock is poor.(2) electronic amplifier circuit exists significant disadvantages to be: for big excess current, this power amplifier can not be sent the corresponding compensation electric current, in this case, because core sataration, magnetic potential balance is damaged, otherwise, require power amplifier to do very greatly, this is uneconomic.
According to the shortcoming that above-mentioned prior art exists, the invention provides a kind of AC/DC current comparator of open type.
For finishing above-mentioned purpose, the present invention takes following technical measures, and Fig. 1 is an open type AC/DC current comparator measuring head outside drawing, and Fig. 2 is a measuring head Hough face A cut-open view, and Fig. 3 is a comparator circuit diagram of the present invention.This AC/dc current comparison instrument is made of measuring head and electron-amplifier two parts, and described measuring head is the annular opening shape, is made of upper and lower two semi-rings, establishes Hough face A and B in diametric(al).Interchange main iron core T in the measuring head
2After being wound into ring-type shape iron core by siliconized plate, detect winding W around last interchange outside
D, again this winding outside around on monitor around level W
K, at W
kThe outside is around exchanging zeroing winding W
aTwo direct current main iron core T
3After being rolled into ring-type shape iron core by siliconized plate, respectively outside around last field winding W
aThen, with above-mentioned interchange, the assembly unit of direct current winding iron core, their outsides around on electrostatic screening E, and it is placed the magnetic shielding iron core T that is reeled and to be formed by siliconized plate
1In, at T
1The outside is around last alternating current-direct current Secondary Winding W
s, outermost puts electrostatic screening F, said structure after the epoxy resin casting, opens Hough face A and B in diametric(al).Secondary AC electric current I in the described electron-amplifier
SaThe mutual inductance direct-coupled circuit be Secondary Winding W
sIn the overwhelming majority (about 99%) alternating current (I
Sa-I
M) produce by the mutual inductance direct-coupled circuit, this mutual inductice coupled circuit is by Secondary Winding W
s, pull-up resistor B, electrochemical capacitor C
1, C
2, diode D
1, D
2Constitute, wherein D
1Anode and D
2Negative electrode link to each other, receive W
sNon-same polarity and the output terminal of amplidyne A, D
1Negative electrode and C
1Positive pole link D
2Anode and C
2Negative pole link to each other C
1Negative pole and C
2The positive pole back that links to each other be connected with the earth point of load B and amplifier, the other end of load B is received W
sEnd of the same name.Fig. 3 has provided the electrical schematic diagram of open type AC/dc current comparison instrument, as a tested winding W
pIn by the AC and DC electric current I
Pa+ I
PdThe time, to AC compounent I
Pa, based on exchanging magnetic potential equilibrium principle, Secondary Winding W
sIn can induce the secondary AC electric current I '
Sa, because this secondary current I
SaIn exist the magnetization current error of some, promptly at main iron core T
2Middle effect has the interchange ampere-turn difference I of some
PaW
p-I
SaW
s, this ampere-turn difference will exchange detection winding W
DMiddle induced signal, W
DThe signal of obtaining amplifies, feeds back by electron-amplifier, is compensated the magnetization current I of secondary AC electric current
M, make at main iron core T
2In ampere-turn difference I
PaW
p-I
SaW
sApproach zero, thereby obtain the high precision turn ratio relation between secondary current and the primary current, I
Pa=(Ws)/(We) I
Sa, flow through the very high secondary AC electric current I of accuracy among the external load B
Sa, pass through I
SaCan determine I
PaIn order to guarantee this system's high precision, to work highly reliably, be provided with and exchange zeroing winding W
aMonitor winding W with exchanging
kW
aBe in series with the parallel branch of secret potential source e and resistance R, capacitor C, the value of choose reasonable R, C can obtain the best adjusting zero effect that exchanges, thus effectively suppress since the straight-flow system ripple to the AC system influence at zero point.Exchange and monitor winding W
kElectronic section or other parts break down in case link to each other with monitoring arrangement K, and the accuracy of its secondary current just changes, main iron core T
2Neutralization exchanges magnetic potential just can not level off to zero, monitors that winding then has a bigger signal output this moment, thereby constitutes the self-diagnostic function of this open type AC current comparator.As shown in Figure 3, for a winding W
pIn DC component I
Pd, adopt the magnetic modulation principle to test.Evenly be wound on a pair of direct current main iron core T
3On a pair of excitation winding W
sButt joint back incoming transport Industrial Frequency Transformer T
4, through a pair of T of pairing
3The effect in industrial frequency AC magnetic field will be subjected to.In a winding, there is tested DC component I
PdThe time, at direct current main iron core T
3In effect is had corresponding D.C. magnetic field, this D.C. magnetic field will be subjected to the modulation of AC magnetic field.To export AC signal based on second harmonic, the corresponding tested direct current I of the amplitude of this signal by the center tap M of exciter transformer with phase place
PdSize and Orientation, filtering, demodulation, amplifying element A through electronic unit is formed give Secondary Winding W
sFeedback DC current I is provided
Sd, because system's open-loop gain is very high, when the closed-loop system balance, make direct current once and the ampere-turn difference between the secondary level off to zero, i.e. I
PdW
p-I
SdW
s=0, get I
Pd=(Ws)/(Wp) I
SdThereby, in load B, also can obtain the very high secondary DC current I of turn ratio accuracy
Sd
Fig. 1 open type AC current comparator measuring head outside drawing.
Fig. 2 measuring head Hough face A cut-open view.
Fig. 3 open type AC/dc current comparison instrument circuit diagram.
The present invention has following many-sided advantage: (one) gage outfit iron core all replaces cost to exceed thin film alloys high permeability material more than 10 times with common silicon steel material cheaply, not only the complete machine cost is low, easily manufactured, and can bear strong machinery, electromagnetic impact, be convenient to industrial promoting the use of. (2) gage outfit is the open type structure that upper and lower two semi-rings form, and the on-the-spot test mounting or dismounting are very convenient, avoid the mounting or dismounting of power failure, mounting or dismounting and the tested transformer of tested bus. (3) the present invention has broken through the interchange secondary current provides by amplifier, requires power amplifier enough big, poor reliability, high in cost of production series of problems thereby bring. (4) this device both can be measured DC current, also can measure alternating current, also can measure simultaneously ac and dc current. (5) this comparator is provided with the running status self-diagnostic function.
After tested, open type AC/DC comparator such as AC and DC rated current are 4000A, import simultaneously winding W at interchange, direct current one time with the number of ampere turns of various combinationpIn, survey its exchange error in 1% rated current (40A) in 100% rated current (4000A) wide region, it is 50PPm that its relative error (comprising in-phase component and quadrature component) all is no more than 0.005%(), test data is as shown in table 1 for exchanging error information table, the ppm of unit. (table 1 sees that literary composition is rear)
Table 1
The AC-AC electric current
Exchange error 40 ampere-turns 400 ampere-turns 1000 ampere-turns 2000 ampere-turns 3000 ampere-turns 4000 ampere-turns
Direct current
Ampere-turn inphase quadrature inphase quadrature inphase quadrature inphase quadrature inphase quadrature homophase
0 +18 +13 +16 +15 +13 +8 +7 +8 +6 +4 +5 +3
40 +18 +13 +16 +15 +13 +8 +7 +8 +6 +4 +5 +3
400 +20 +14 +15 +16 +13 +8 +7 +8 +5 +4 +5 +3
1000 +20 +13 +14 +17 +13 +8 +6 +9 +5 +4 -
2000 +12 +20 +12 +20 +12 +9 +5 +10 +4 +5 -
3000 +14 +20 +11 +20 +11 +9 +5 +11 - -
4000 +14 +20 +11 +21 - - - -
Claims (1)
1, a kind of AC/dc current comparison instrument is made of measuring head and electron-amplifier two parts, and it is characterized by described measuring head is the annular opening shape, is made of upper and lower two semi-rings, establishes Hough face A and B in diametric(al), and measuring head is made of following several parts:
A) exchange main iron core T
2After being wound into ring-type shape iron core by siliconized plate, detect winding W around last interchange outside
D, again in this winding outside around monitoring winding W
K, monitoring winding W
KThe outside is around exchanging zeroing winding W
a
B) two direct current main iron core T
3After being rolled into ring-type shape iron core by siliconized plate, respectively outside around last field winding W
a
C) with a), b) described winding assembly unit, their outsides around on electrostatic screening layer E and it is placed the magnetic shielding iron core T that is reeled and to be formed by siliconized plate
1In, at T
1The outside is around last alternating current-direct current Secondary Winding W
a, outermost puts electrostatic screening layer F;
D) said structure is opened Hough face A and B in diametric(al) after the epoxy resin casting,
Secondary AC electric current I in the described electron-amplifier
5aThe mutual inductance direct-coupled circuit by Secondary Winding W
a, pull-up resistor B, electrochemical capacitor C
1, C
2, diode D
1, D
2Constitute, wherein D
1Anode and D
2Negative electrode link to each other, receive W
aNon-same polarity and the output terminal of amplidyne A, D
1Negative electrode and C
1Positive pole link to each other D
2Anode and C
2Negative pole link to each other C
1Negative pole and C
2The positive pole back that links to each other be connected with the earth point of amplifier A with load B, the other end of load B is received W
aEnd of the same name.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN 92103969 CN1029494C (en) | 1992-05-21 | 1992-05-21 | AC/DC current comparator |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN 92103969 CN1029494C (en) | 1992-05-21 | 1992-05-21 | AC/DC current comparator |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| CN1079053A CN1079053A (en) | 1993-12-01 |
| CN1029494C true CN1029494C (en) | 1995-08-09 |
Family
ID=4940551
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN 92103969 Expired - Fee Related CN1029494C (en) | 1992-05-21 | 1992-05-21 | AC/DC current comparator |
Country Status (1)
| Country | Link |
|---|---|
| CN (1) | CN1029494C (en) |
Families Citing this family (6)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JP5222542B2 (en) * | 2007-12-07 | 2013-06-26 | 矢崎総業株式会社 | Current sensor |
| JP2013088349A (en) * | 2011-10-20 | 2013-05-13 | Alps Green Devices Co Ltd | Current sensor |
| CN108008173B (en) * | 2016-10-28 | 2020-02-18 | 致茂电子股份有限公司 | Alternating current-direct current superposition testing device |
| CN107817372B (en) * | 2017-12-14 | 2023-10-27 | 华中科技大学 | Direct current and alternating current heavy current sensing head and metering device |
| CN108519508B (en) * | 2018-03-16 | 2023-12-05 | 华中科技大学 | Comparator for measuring alternating current and direct current |
| CN108226610B (en) * | 2018-03-16 | 2023-12-26 | 华中科技大学 | Clamp type measuring device for alternating current and direct current small current |
-
1992
- 1992-05-21 CN CN 92103969 patent/CN1029494C/en not_active Expired - Fee Related
Also Published As
| Publication number | Publication date |
|---|---|
| CN1079053A (en) | 1993-12-01 |
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