CN107703346A - A kind of Weak current monitoring circuit being used under earthing or grounding means condition of spark - Google Patents
A kind of Weak current monitoring circuit being used under earthing or grounding means condition of spark Download PDFInfo
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- CN107703346A CN107703346A CN201711192494.8A CN201711192494A CN107703346A CN 107703346 A CN107703346 A CN 107703346A CN 201711192494 A CN201711192494 A CN 201711192494A CN 107703346 A CN107703346 A CN 107703346A
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- G—PHYSICS
- G01—MEASURING; TESTING
- G01R—MEASURING ELECTRIC VARIABLES; MEASURING MAGNETIC VARIABLES
- G01R19/00—Arrangements for measuring currents or voltages or for indicating presence or sign thereof
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Abstract
The present invention provides a kind of Weak current monitoring circuit being used under earthing or grounding means condition of spark, the I/V change-over circuits for the T-shaped negative feedback current photovoltaic conversion structure that the circuit is built using several accurate small resistors, relatively single accurate super large metalfilmresistor, T-shaped negative feedback current photovoltaic conversion phone can substantially reduce input impedance, shunting of the lower spark discharge electric current on earthing or grounding means and amplifier load can effectively be subtracted, and then reduce systematic error, coordinate quadravalence chebyshev low-pass filter to gas current shaping, move the advanced Anti-Jamming Technique of small-signal detection field simultaneously, make detection electric current more accurate, the change spark discharge current detection circuit is applicable not only to earthing or grounding means Weak current under condition of spark and detected, it is also applied for other electrical equipments, with high value of practical.
Description
Technical field
The present invention relates to anti-thunder technical field, is used for more particularly, to a kind of under earthing or grounding means condition of spark
Weak current monitoring circuit.
Background technology
In lightning Protection Design, ground connection is for lightning current is smoothly spewed out into underground, to reduce the overvoltage caused by it.Connect
Ground is part indispensable in lightning protection device.Lightning protection resistance mainly forms power frequency earthing resistance by two parts
And impulse earthed resistance.When defeated, distribution line is by being struck by lightning, dash current is scattered by earthing or grounding means to ground, in impact electricity
Under stream effect, when the current density of grounded body outflow exceedes the basic field strength of soil, one just occurs around grounding body
Spark discharge area, equivalent to the effective dimensions for changing grounding body, that is, the grounding resistance of earthing or grounding means can occur when being struck by lightning
Change.Existing research shows that impulse resistance influences notable on defeated, distribution line Lightning performance.Therefore, thunderbolt impact is carried out
The research of resistance is significant for defeated, distribution line lightning protection.
At present, carry out numerous studies for influence of the dash current to grounding resistance, but be related to spark discharge to ground connection
The research of the influence of resistance is few, and more based on emulation.Therefore, carry out and especially occur connecing during spark discharge under dash current
The experimental study of the grounding resistance change of ground device, and then the method for proposing new reduction grounding resistance, improve defeated, distribution line
It is significant for resistance to thunder level.
I/V, which changes more commonly used method, in being detected currently for discharge current two kinds, and one senses for Current Voltage
Device, this method is simple, and can guarantee that certain sensitivity, but the cost of Current Voltage sensor is general higher, warp
Ji property is not high, second, realizing that Current Voltage is changed using electric resistance partial pressure principle.For electric resistance partial pressure principle, typically there are two kinds
The amplifying circuit of the electric current input of structure realizes that I/V is changed, as shown in Figure 1.
Fig. 1-(a) is to be amplified again after input resistance converts electrical current into voltage；Fig. 1-(b) is reduced using negative-feedback
Input impedance, realize electric current input amplification.In Fig. 1-(a) circuits, electric current forms current potential on Rc, becomes followed by output end
Change, output terminal potential is output amplitude, and this current potential can change with the change of input current, and the electric current of change can be straight
Connect and be fed on pipe collector, so as to influence the sensitivity of spark discharge current detecting.In Fig. 1-(b), as long as in theory
Rc is sufficiently large, even if the electric current very little of input, can also export preferable voltage Vout, but in actual circuit, the input of amplifier
Impedance can not possibly be infinitely great.Consider bias current I simultaneouslybTo being tested spark discharge electric current I+Influence, reality output is：Vout
=-(I+-Ib)Rc, as bias current IbMore than tested spark discharge electric current I+, then being tested spark discharge electric current will flood and lead
Cause can not detect.
The content of the invention
The present invention provides a kind of Weak current monitoring circuit being used under earthing or grounding means condition of spark, and the circuit is effective
Having determined causes the problem for being not easy detection or distorted signals because spark discharge electric current is faint, improves earthing or grounding means resistance detection
The degree of accuracy.
In order to reach above-mentioned technique effect, technical scheme is as follows：
A kind of Weak current monitoring circuit being used under earthing or grounding means condition of spark, it is characterised in that including sequentially
The anti-jamming circuit of connection, T-shaped negative feedback current voltage conversion circuit and quadravalence Butterworth LPF；Earthing or grounding means fire
Flower discharge current is output to the current input terminal of T-shaped negative feedback current voltage conversion circuit, T-shaped negative-feedback after anti-jamming circuit
The voltage output end of current-to-voltage converting circuit is connected to quadravalence Butterworth LPF voltage input end.
Further, the anti-jamming circuit includes three coaxial sockets, the first low-impedance amplifier T1 and the second Low ESR
Amplifier T2, resistance R31, R32, R33, electric capacity C3；Resistance R31 one end is connected with resistance R32 one end, and resistance R31's is another
The coaxial socket of one end three is connected to the first low-impedance amplifier T1 negative input end, and the resistance R32 other end is connected to second
Low-impedance amplifier T2 negative input end, the second low-impedance amplifier T2 positive input terminal are connected to the first low-resistance through resistance R33
Anti- amplifier T1 positive input terminal.
Further, the T-shaped negative feedback current voltage conversion circuit include LF353 operational amplifiers, resistance R1, R2,
Rc；First low-impedance amplifier T1 output end is connected with the negative input end of LF353 operational amplifiers, LF353 operational amplifiers
One end also with resistance R1 of negative input end be connected, the resistance R1 other end is connected with resistance R2 one end, resistance R1 and resistance
One end of tie point and resistance Rc between R2 is grounded, resistance Rc other end ground connection, resistance the R2 other end and LF353 computings
The output end connection of amplifier, the positive input terminal ground connection of LF353 operational amplifiers.
Further, described quadravalence Butterworth LPF include resistance R11, R12, R13, R14, R21, R22,
R23, R24, the first LF353 amplifiers, the 2nd LF353 amplifiers, electric capacity C11, C12, C21, C22；LF353 operational amplifiers
Output end is connected with resistance R11 one end, and resistance R11 other end connection is connected with resistance R12 one end, and resistance R12's is another
One end is connected with the positive input terminal of the first LF353 amplifiers, resistance R13 one end and the negative input end of the first LF353 amplifiers
Connection, resistance R13 other end ground connection, resistance R14 one end are connected with the negative input end of the first LF353 amplifiers, resistance R14
The other end with；Between electric capacity C11 one end and resistance R11 and resistance R12 tie point connection, the electric capacity C11 other end with
The output end connection of first LF353 amplifiers, the positive input terminal connection of the electric capacity C12 LF353 amplifiers of one end the first, electric capacity
C12 other end ground connection；The output end of first LF353 amplifiers is also connected with resistance R21, the resistance R21 other end with electricity
R22 one end connection is hindered, the resistance R22 other end is connected with the positive input terminal of the 2nd LF353 amplifiers, resistance R23 one end
It is connected with the negative input end of the 2nd LF353 amplifiers, resistance R23 other end ground connection, resistance R24 one end and the 2nd LF353
Amplifier negative input end connection, the resistance R24 other end with；Between electric capacity C21 one end and resistance R21 and resistance R22
Tie point is connected, and the electric capacity C21 other end is connected with the output end of the 2nd LF353 amplifiers, electric capacity C22 one end second
The positive input terminal connection of LF353 amplifiers, electric capacity C22 other end ground connection.
Preferably, the first low-impedance amplifier T1 and the second low-impedance amplifier T2 is OPA348 type amplifiers.
Compared with prior art, the beneficial effect of technical solution of the present invention is：
The present invention has counted T-shaped negative feedback current voltage conversion circuit, quadravalence Butterworth LPF, has used small letter
Number advanced antijamming measure of detection field, the collection of Weak current under the ground device condition of spark that achieves a butt joint, effectively certainly
Cause because spark discharge electric current is faint the problem for being not easy detection or distorted signals, improve the standard of earthing or grounding means resistance detection
Exactness.
Brief description of the drawings
Fig. 1 is two kinds of structure charts of electric current input amplification in the prior art；
Fig. 2 is anti-jamming circuit schematic diagram；
Fig. 3 is T-shaped negative feedback current photovoltaic conversion circuit diagram；
Fig. 4 is quadravalence chebyshev low-pass filter schematic diagram.
Embodiment
Accompanying drawing being given for example only property explanation, it is impossible to be interpreted as the limitation to this patent；
In order to more preferably illustrate the present embodiment, some parts of accompanying drawing have omission, zoomed in or out, and do not represent actual product
Size；
To those skilled in the art, it is to be appreciated that some known features and its explanation, which may be omitted, in accompanying drawing
's.
Technical scheme is described further with reference to the accompanying drawings and examples.
Embodiment 1
A kind of Weak current monitoring circuit being used under earthing or grounding means condition of spark, it is characterised in that including sequentially
The anti-jamming circuit of connection, T-shaped negative feedback current voltage conversion circuit and quadravalence Butterworth LPF；Earthing or grounding means fire
Flower discharge current is output to the current input terminal of T-shaped negative feedback current voltage conversion circuit, T-shaped negative-feedback after anti-jamming circuit
The voltage output end of current-to-voltage converting circuit is connected to quadravalence Butterworth LPF voltage input end.
As shown in Fig. 2 anti-jamming circuit includes three coaxial sockets, the first low-impedance amplifier T1 and the amplification of the second Low ESR
Device T2, resistance R31, R32, R33, electric capacity C3；Resistance R31 one end is connected with resistance R32 one end, the resistance R31 other end
The first low-impedance amplifier T1 negative input end is connected to through three coaxial sockets, the resistance R32 other end is connected to the second low-resistance
Anti- amplifier T2 negative input end, the second low-impedance amplifier T2 positive input terminal are connected to the first Low ESR through resistance R33 and put
Big device T1 positive input terminal；First low-impedance amplifier T1 and the second low-impedance amplifier T2 is OPA348 type amplifiers.
As shown in figure 3, T-shaped negative feedback current voltage conversion circuit includes LF353 operational amplifiers, resistance R1, R2, Rc；
First low-impedance amplifier T1 output end is connected with the negative input end of LF353 operational amplifiers, and LF353 operational amplifiers are born
The one end of input also with resistance R1 is connected, and the resistance R1 other end is connected with resistance R2 one end, resistance R1 and resistance R2 it
Between tie point and resistance Rc one end be grounded, resistance Rc other end ground connection, resistance the R2 other end and LF353 operation amplifiers
The output end connection of device, the positive input terminal ground connection of LF353 operational amplifiers.
Output voltage V can be obtained according to schematic diagramoutExpression formula：
Because spark discharge electric current can shunt on earthing or grounding means and amplifier load, so spark discharge current detecting
Input impedance is smaller, caused by systematic error accordingly can also reduce.Using T-shaped negative feedback current photovoltaic conversion circuit, can incite somebody to action
Input impedance reduces several orders of magnitude, can set R1=Rc=1k Ω, R2=2k Ω so that output voltage range be 2mV~
2V, so that follow-up modulate circuit is to signal shaping.
As shown in figure 4, quadravalence Butterworth LPF include resistance R11, R12, R13, R14, R21, R22, R23,
R24, the first LF353 amplifiers, the 2nd LF353 amplifiers, electric capacity C11, C12, C21, C22；The output of LF353 operational amplifiers
End is connected with resistance R11 one end, and resistance R11 other end connection is connected with resistance R12 one end, the resistance R12 other end
It is connected with the positive input terminal of the first LF353 amplifiers, resistance R13 one end is connected with the negative input end of the first LF353 amplifiers,
Resistance R13 other end ground connection, resistance R14 one end are connected with the negative input end of the first LF353 amplifiers, and resistance R14's is another
One end with；Tie point connection between electric capacity C11 one end and resistance R11 and resistance R12, the electric capacity C11 other end and first
The output end connection of LF353 amplifiers, the positive input terminal connection of the electric capacity C12 LF353 amplifiers of one end the first, electric capacity C12's
The other end is grounded；The output end of first LF353 amplifiers is also connected with resistance R21, the resistance R21 other end with resistance R22
One end connection, the resistance R22 other end is connected with the positive input terminal of the 2nd LF353 amplifiers, resistance R23 one end and second
The negative input end connection of LF353 amplifiers, resistance R23 other end ground connection, resistance R24 one end and the 2nd LF353 amplifiers
Negative input end connection, the resistance R24 other end with；Tie point between electric capacity C21 one end and resistance R21 and resistance R22
Connection, the electric capacity C21 other end are connected with the output end of the 2nd LF353 amplifiers, the electric capacity C22 LF353 of one end the 2nd amplifications
The positive input terminal connection of device, electric capacity C22 other end ground connection.
In order to eliminate the interference of 150kHz and above high-frequency noise to spark discharge current detecting, by analyzing spark discharge
The frequecy characteristic of electric current, quadravalence Chebyshev low pass filter device, wherein n ranks Chebyshev low pass filtered are set in current output terminal
The amplitude and amplitude-frequency relation such as following formula of ripple device：
Using high impedance, the single-chip double operational device of Low-bias Current sets low pass filter.Ginseng in initialization circuit
Number is：C11=C12=C21=C22=100nF, R11=R12=R21=R22=10k Ω.Cut-off frequency is：
The I/V conversions for the T-shaped negative feedback current photovoltaic conversion structure that the present invention is built using several accurate small resistors
Circuit, relatively single accurate super large metalfilmresistor, T-shaped negative feedback current photovoltaic conversion phone can substantially reduce input impedance,
Shunting of the lower spark discharge electric current on earthing or grounding means and amplifier load can effectively be subtracted, and then reduce systematic error, coordinate four
Rank chebyshev low-pass filter moves the advanced Anti-Jamming Technique of small-signal detection field to gas current shaping, makes
Detection electric current is more accurate, and it is small that the change spark discharge current detection circuit is applicable not only to earthing or grounding means under condition of spark
Current detecting, other electrical equipments are also applied for, there is high value of practical.
Same or analogous label corresponds to same or analogous part；
Position relationship is used for being given for example only property explanation described in accompanying drawing, it is impossible to is interpreted as the limitation to this patent；
Obviously, the above embodiment of the present invention is only intended to clearly illustrate example of the present invention, and is not pair
The restriction of embodiments of the present invention.For those of ordinary skill in the field, may be used also on the basis of the above description
To make other changes in different forms.There is no necessity and possibility to exhaust all the enbodiments.It is all this
All any modification, equivalent and improvement made within the spirit and principle of invention etc., should be included in the claims in the present invention
Protection domain within.
Claims (5)
1. a kind of Weak current monitoring circuit being used under earthing or grounding means condition of spark, it is characterised in that including sequentially connecting
Anti-jamming circuit, T-shaped negative feedback current voltage conversion circuit and the quadravalence Butterworth LPF connect；Earthing or grounding means spark
Discharge current is output to the current input terminal of T-shaped negative feedback current voltage conversion circuit, T-shaped negative-feedback electricity after anti-jamming circuit
The voltage output end of stream voltage conversion circuit is connected to quadravalence Butterworth LPF voltage input end.
2. the Weak current monitoring circuit according to claim 1 being used under earthing or grounding means condition of spark, its feature
It is, the anti-jamming circuit includes three coaxial sockets, the first low-impedance amplifier T1 and the second low-impedance amplifier T2, resistance
R31, R32, R33, electric capacity C3；Resistance R31 one end is connected with resistance R32 one end, and the resistance R31 other end is coaxial slotting through three
Seat is connected to the first low-impedance amplifier T1 negative input end, and the resistance R32 other end is connected to the second low-impedance amplifier T2
Negative input end, the second low-impedance amplifier T2 positive input terminal is being connected to the first low-impedance amplifier T1 just through resistance R33
Input.
3. the Weak current monitoring circuit according to claim 2 being used under earthing or grounding means condition of spark, its feature
It is, the T-shaped negative feedback current voltage conversion circuit includes LF353 operational amplifiers, resistance R1, R2, Rc；First Low ESR
Amplifier T1 output end is connected with the negative input end of LF353 operational amplifiers, the negative input ends of LF353 operational amplifiers also with
Resistance R1 one end connection, the resistance R1 other end are connected with resistance R2 one end, the tie point between resistance R1 and resistance R2
It is grounded with resistance Rc one end, resistance Rc other end ground connection, the resistance R2 other end and the output end of LF353 operational amplifiers
Connection, the positive input terminal ground connection of LF353 operational amplifiers.
4. the Weak current monitoring circuit according to claim 3 being used under earthing or grounding means condition of spark, its feature
It is, described quadravalence Butterworth LPF includes resistance R11, R12, R13, R14, R21, R22, R23, R24, and first
LF353 amplifiers, the 2nd LF353 amplifiers, electric capacity C11, C12, C21, C22；The output end and resistance of LF353 operational amplifiers
R11 one end connection, resistance R11 other end connection are connected with resistance R12 one end, the resistance R12 other end and first
The positive input terminal connection of LF353 amplifiers, resistance R13 one end are connected with the negative input end of the first LF353 amplifiers, resistance
R13 other end ground connection, resistance R14 one end are connected with the negative input end of the first LF353 amplifiers, the resistance R14 other end
With；Tie point connection between electric capacity C11 one end and resistance R11 and resistance R12, the electric capacity C11 other end and the first LF353
The output end connection of amplifier, the positive input terminal connection of the electric capacity C12 LF353 amplifiers of one end the first, the electric capacity C12 other end
Ground connection；The output end of first LF353 amplifiers is also connected with resistance R21, the resistance R21 other end and one end with resistance R22
Connection, the resistance R22 other end are connected with the positive input terminal of the 2nd LF353 amplifiers, resistance R23 one end and the 2nd LF353
The negative input end connection of amplifier, resistance R23 other end ground connection, resistance R24 one end are negative defeated with the 2nd LF353 amplifiers
Enter end connection, the resistance R24 other end with；Tie point connection between electric capacity C21 one end and resistance R21 and resistance R22, electricity
Hold C21 the other end be connected with the output end of the 2nd LF353 amplifiers, the electric capacity C22 LF353 amplifiers of one end the 2nd it is just defeated
Enter end connection, electric capacity C22 other end ground connection.
5. the Weak current monitoring circuit according to claim 4 being used under earthing or grounding means condition of spark, its feature
It is, the first low-impedance amplifier T1 and the second low-impedance amplifier T2 are OPA348 type amplifiers.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201711192494.8A CN107703346A (en) | 2017-11-24 | 2017-11-24 | A kind of Weak current monitoring circuit being used under earthing or grounding means condition of spark |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201711192494.8A CN107703346A (en) | 2017-11-24 | 2017-11-24 | A kind of Weak current monitoring circuit being used under earthing or grounding means condition of spark |
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| Publication Number | Publication Date |
|---|---|
| CN107703346A true CN107703346A (en) | 2018-02-16 |
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| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN201711192494.8A Pending CN107703346A (en) | 2017-11-24 | 2017-11-24 | A kind of Weak current monitoring circuit being used under earthing or grounding means condition of spark |
Country Status (1)
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| CN (1) | CN107703346A (en) |
Citations (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN106199143A (en) * | 2016-09-07 | 2016-12-07 | 哈尔滨理工大学 | Micro-current detecting system in dielectric insulation diagnosis |
| CN106385238A (en) * | 2016-08-31 | 2017-02-08 | 兰州空间技术物理研究所 | Ion current amplifying circuit for collecting electrode of vacuum ionization gauge |
-
2017
- 2017-11-24 CN CN201711192494.8A patent/CN107703346A/en active Pending
Patent Citations (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN106385238A (en) * | 2016-08-31 | 2017-02-08 | 兰州空间技术物理研究所 | Ion current amplifying circuit for collecting electrode of vacuum ionization gauge |
| CN106199143A (en) * | 2016-09-07 | 2016-12-07 | 哈尔滨理工大学 | Micro-current detecting system in dielectric insulation diagnosis |
Non-Patent Citations (1)
| Title |
|---|
| 刘兴利: "《中国优秀硕士学位论文全文数据库》", 《基于非晶材料的地磁检测问题研究》 * |
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Application publication date: 20180216 |