CN104345196A - Active weak power frequency current induction coil - Google Patents
Active weak power frequency current induction coil Download PDFInfo
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- CN104345196A CN104345196A CN201410597519.2A CN201410597519A CN104345196A CN 104345196 A CN104345196 A CN 104345196A CN 201410597519 A CN201410597519 A CN 201410597519A CN 104345196 A CN104345196 A CN 104345196A
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Abstract
The invention discloses an active weak power frequency current induction coil which comprises a flexible induction coil, a sampling and integrating circuit, an active differential amplification circuit and a voltage tracker, wherein the flexible induction coil is used for converting a coupled magnetic field into an alternating current signal and outputting to the sampling and integrating circuit; the sampling and integrating circuit is used for sampling the received alternating current signal, acquiring a power frequency voltage signal and outputting to the active differential amplification circuit; the active differential amplification circuit is used for amplifying the received power frequency voltage signal and then outputting to the voltage tracker; the voltage tracker is used for isolating and buffering the amplified power frequency voltage signal and outputting a voltage signal. A non-contact method is adopted by the invention, the power frequency leakage current of a surge protective device is conveniently detected and the active weak power frequency current induction coil is widely applied to a detection project for the power frequency leakage current of the surge protective device of a lightning protection device.
Description
Technical field
The present invention relates to thunder and lightning science and technology field, particularly a kind of active faint power current inductive coil.
Background technology
Lightning current is a kind of typical transient current pulse, thunderbolt occur in transmission line of electricity often causes transmission line of electricity open circuit, short circuit and insulating property the phenomenon such as change.According to the designing requirement of Code for design of lightning protection of buildings GB50057-2010, surge protector is installed in transmission line of electricity for discharging and suppress the energy of lightning wave.Surge protector is in release with while suppressing lightning wave energy, and certain energy conversion of lightning wave is become heat energy by self, makes the performance generation deterioration phenomenon of himself.The appearance of deterioration usually shows as the open circuit of device, the power frequency leakage current of short circuit and device becomes large.First two phenomenon ratio is easier to detect, and phenomenon is obvious.But the power frequency leakage current of device becomes large phenomenon and is not easy to detect, and is all that it but can affect to transmission line of electricity, because leakage current causes greatly power transmission line protective device of leakage current to trip, makes transmission line of electricity cisco unity malfunction.Leakage current becomes also can cause device heating greatly, causes the accidents such as fire.
Therefore, according to building lightning protection device testing requirement, the surge protection device that reply is arranged on transmission line of electricity carries out periodic detection.At present, in the project detected, the power frequency leakage current test of surge protection device is commonly used conventional method and is connected in surge protection device circuit by alternating current ammeter and measures.But this detection method inconvenient operation, detects also dangerous.
How to overcome the deficiencies in the prior art and become an existing thunder and lightning science and technology field emphasis difficult problem urgently to be resolved hurrily.
Summary of the invention
Technical matters to be solved by this invention overcomes the deficiencies in the prior art and provides a kind of active faint power current inductive coil; the present invention is arranged on the leakage current of surge protection device in transmission line of electricity for detecting, realize the regular Performance Detection to surge protector in lightning protection device.
The present invention is for solving the problems of the technologies described above by the following technical solutions:
According to the active faint power current inductive coil of one that the present invention proposes, comprise flexible inductive coil, sampling and integrating circuit, active differential amplifying circuit and voltage follower; Wherein,
Flexible inductive coil, for being converted to ac current signal by the magnetic field of being coupled to and exporting sampling and integrating circuit to;
Sampling and integrating circuit, for sampling the ac current signal received, and obtain power-frequency voltage signal and export active differential amplifying circuit to;
Active differential amplifying circuit, exports voltage follower to after being amplified by the power-frequency voltage signal of reception;
Voltage follower, the power-frequency voltage signal for isolating, after Hyblid Buffer Amplifier, output voltage signal.
As the further prioritization scheme of the active faint power current inductive coil of one of the present invention, described flexible inductive coil comprises flexible back bone, intert copper post in flexible back bone and close around two-layer wire on flexible back bone; Flexible inductive coil has two output terminals: the first output terminal and the second output terminal.
As the further prioritization scheme of the active faint power current inductive coil of one of the present invention, described flexible back bone is electrically insulating silicone rubber pipe, and described wire is soft high temperature wire.
As the further prioritization scheme of the active faint power current inductive coil of one of the present invention, described sampling and integrating circuit comprise the first resistance, the second resistance and electric capacity; Wherein,
One end of first resistance is connected respectively with one end of the second resistance, the first output terminal, and the other end of the second resistance is connected with one end of electric capacity, and the other end of the first resistance is connected respectively with the other end of the second output terminal, electric capacity.
As the further prioritization scheme of the active faint power current inductive coil of one of the present invention, described active differential amplifying circuit comprises the three to ten resistance, and voltage follower comprises the first voltage follower, the second voltage follower and tertiary voltage follower; Wherein,
One end of 3rd resistance is connected with one end of electric capacity, the other end of the 3rd resistance is connected respectively with one end of the 5th resistance, the negative input end of the first voltage follower, the positive input terminal ground connection of the first voltage follower, the output terminal of the first voltage follower is connected with one end of the 7th resistance, the other end of the 7th resistance is connected respectively with one end of the 9th resistance, the negative input end of tertiary voltage follower, and the other end of the 9th resistance is connected with the output terminal of tertiary voltage follower; One end of 4th resistance is connected with the other end of electric capacity, the other end of the 4th resistance is connected with one end of the 6th resistance, the negative input end of the second voltage follower, the positive input terminal ground connection of the second voltage follower, the other end of the 6th resistance is connected respectively with one end of the output terminal of the second voltage follower, the 8th resistance, the other end of the 8th resistance is connected respectively with one end of the positive input terminal of tertiary voltage follower, the tenth resistance, the other end ground connection of the tenth resistance.
The present invention adopts above technical scheme compared with prior art, has following technique effect:
(1) measurement range of active faint power current inductive coil of the present invention is large, measures power current from 1 μ A ~ 10mA, meets the testing requirement of surge protector power frequency leakage current;
(2) this inductive coil adopts active amplifying circuit, and detection sensitivity is high, and the impact of display load on measuring accuracy is little;
(3) skeleton of this induction adopts flexible silicone rubber material, has moisture proof, waterproof, good insulation preformance, use safety;
(4) when this inductive coil is measured, and be non-contacting, easy to operate, safe and reliable between electrified body;
(5) this inductive coil measuring accuracy is high, and error range is little, and measuring average error is ± 1.03%;
(6) this inductive coil has wide range of applications; be equally applicable to the detection responding to insulated terminal power frequency leakage current; detect the power frequency leakage current of surge protection device easily, be widely used in the test item of the power frequency leakage current of lightning protection device surge protector.
Accompanying drawing explanation
Fig. 1 is functional-block diagram of the present invention.
Fig. 2 is flexible induction coil configuration figure in the present invention.
Fig. 3 is sampling and integrating circuit figure in the present invention.
Fig. 4 is active differential amplifying circuit and voltage follower circuit figure in the present invention.
Embodiment
Below in conjunction with accompanying drawing, technical scheme of the present invention is described in further detail:
Be functional-block diagram of the present invention as shown in Figure 1, according to the active faint power current inductive coil of one that the present invention proposes, comprise flexible inductive coil, sampling and integrating circuit, active differential amplifying circuit and voltage follower; Wherein,
Flexible inductive coil, for being converted to ac current signal by the magnetic field of being coupled to and exporting sampling and integrating circuit to;
Sampling and integrating circuit, for sampling the ac current signal received, obtaining power-frequency voltage signal and exporting active differential amplifying circuit to;
Active differential amplifying circuit, exports voltage follower to after being amplified by the power-frequency voltage signal of reception, improves the sensitivity of inductive coil;
Voltage follower, the power-frequency voltage signal for isolating, after Hyblid Buffer Amplifier, output voltage signal, ensures output voltage signal intensity.
Fig. 2 is flexible induction coil configuration figure in the present invention, and described flexible inductive coil comprises flexible back bone, intert copper post in flexible back bone and close around two-layer wire on flexible back bone; Flexible inductive coil has two output terminals: the first output terminal and the second output terminal.Described flexible back bone is electrically insulating silicone rubber pipe, and described wire is soft high temperature wire.
The principle of flexible inductive coil is the principle in the magnetic field utilizing the electric current that conductor changes to change.When on magnetic Field Coupling to coil, coil will induce electric signal.The skeleton of flexible inductive coil is internal diameter is 4mm, external diameter is 8mm, length is the electrically insulating silicone rubber pipe of 4cm, play a supportive role, and this skeleton has flexibility, insert a long 2cm in its one end, diameter is the copper post of 4mm and the other end inserting rubber tube can make rubber tube encompass a closed loop.On skeleton, the coiling of inductive coil should be closeer with the induction coefficient improving coil.First according to the intensive winding in some directions during winding, be wound to skeleton end continues toward being wound around in the other direction later, and reserved two terminals (the first output terminal and the second output terminal) are connected, for providing induced signal for rear sampling and integrating circuit for sampling and integrating circuit.Wire used during winding should adopt suitably soft high temperature wire.The winding material of inductive coil and the mode of winding are a crucial factors, the induction coefficient of the closeer then coil of coiling is larger, self-induction of loop and stray capacitance larger, its upper limiting frequency can reduce, and this winding method does not have larger impact to the measurement of power current.According to the coiling characteristic of flexible coil, choosing internal diameter is 0.5mm, and external diameter is the 5 core high temperature wires of 1mm, inside conductor has excellent corrosion resistance, acid resistance, alkali resistance, insulation course has excellent electrical insulation capability, can be high pressure resistant, high temperature resistant, has less high-frequency loss.According to the parameter request of flexible coil, rule of thumb formulae discovery:
l＝2n(b-a+h+d)
S
1＝πd
2/4
r＝ρl/S
1；
S
c＝(h+d)(b-a+d)
In formula, a is the internal diameter of silicone rubber tube, and b is the external diameter of silicone rubber tube, and h is that the circle of coiling is high, and d is the diameter of coiling wire, S
1wire cross-section area, S
cbe the sectional area of coil, ρ is the resistivity of copper product, the conductor length used needed for l, and r is resistance; ρ=17.5n Ω m, a=4mm, b=8mm, h=4.4mm.The number of turn of coiling gets 460 circles as calculated.Winding method is close around two-layer, every layer of 230 circle.After coil winding completes, adopt same silicone rubber tube to be encapsulated in the periphery of coil, the internal diameter of silicone rubber tube is 10mm, and external diameter is 14mm, and length is 25cm.First output terminal 1 and second output terminal 2 of coil are that signal output port is for connecting with the first resistance R1.
Fig. 3 is sampling and integrating circuit figure in the present invention, and described sampling and integrating circuit comprise the first resistance R1, the second resistance R2 and electric capacity C; Wherein, one end of the first resistance R1 is connected respectively with one end of the second resistance R2, the first output terminal, and the other end of the second resistance R2 is connected with one end of electric capacity C, and the other end of the first resistance R1 is connected respectively with the other end of the second output terminal, electric capacity C.First resistance R1, the second resistance R2 and this three of electric capacity C arrange with π type.The device parameters of sampling and integrating circuit is chosen and should be calculated according to the parameter of flexible coil: the first resistance R1=275 Ω, wherein R2=100 Ω, C=8 μ F.Port 3 is connected with the 1 and 2 port of flexible coil port respectively with port 4, for sampling and integrating circuit provide signal to input, port 5 and port 6, as the signal input port of next stage active differential amplifying circuit and voltage follower circuit, are connected with port 8 with the port 7 of active differential amplifying circuit and voltage follower circuit.Sampling and integrating circuit, for carrying out sampling obtain power-frequency voltage signal to the ac current signal received, be namely converted into voltage signal the flexible coil current signal obtained that is coupled by the first resistance R1.R1 inside sample resistance formula sample circuit, the voltage signal utilizing integrating circuit to realize exporting to active differential amplifying circuit is directly proportional to the voltage signal on the first resistance R1.
Fig. 4 is active differential amplifying circuit and voltage follower circuit figure in the present invention, described active differential amplifying circuit comprises the three to ten resistance R3, R4, R5, R6, R7, R8, R9, R10, and voltage follower comprises the first voltage follower IC1, the second voltage follower IC2 and tertiary voltage follower IC3; Wherein,
One end of 3rd resistance R3 is connected with one end of electric capacity C, the other end of the 3rd resistance R3 is connected respectively with the negative input end of one end of the 5th resistance R5, the first voltage follower IC1, the positive input terminal ground connection of the first voltage follower IC1, the output terminal of the first voltage follower IC1 is connected with one end of the 7th resistance R7, the other end of the 7th resistance R7 is connected respectively with the negative input end of one end of the 9th resistance R9, tertiary voltage follower IC3, and the other end of the 9th resistance R9 is connected with the output terminal of tertiary voltage follower IC3; One end of 4th resistance R4 is connected with the other end of electric capacity C, the other end of the 4th resistance R4 is connected with the negative input end of one end of the 6th resistance R6, the second voltage follower IC2, the positive input terminal ground connection of the second voltage follower IC2, the other end of the 6th resistance R6 is connected respectively with one end of the output terminal of the second voltage follower IC2, the 8th resistance R8, the other end of the 8th resistance R8 is connected respectively with one end of the positive input terminal of tertiary voltage follower IC3, the tenth resistance R10, the other end ground connection of the tenth resistance R10.
The amplifying circuit gain that first voltage follower IC1, the second voltage follower IC2 are formed is 100 times.The amplifying circuit that tertiary voltage follower IC3 is formed is gain is 1 times, first voltage follower IC1, second voltage follower IC2 is made up of the two-way operational amplifier of LM358, tertiary voltage follower IC3 is made up of single operational amplifier OP27, input signal is connected to the two ends of the electric capacity C of integrating circuit, the power supply of operational amplifier is by ± 12V DC power supply, its course of work is: from the voltage signal of integrating circuit through the first voltage follower IC1, second voltage follower IC2 receives the input amplifier that tertiary voltage follower IC3 is formed after amplifying, exported by output port 9, the device parameters of circuit is: R3=R4=1k Ω, R5=R6=100k Ω, R7=R8=R9=R10=10k Ω.
Voltage follower is that amplifying signal is carried out Buffer output, and rear termination display load, reduces display load device to the impact of active differential amplifying circuit to improve the stability exported.
Complete operation of the present invention is around on wire by the flexible line of induction, voltage signal is induced by the first resistance R1 at flexible inductive coil two ends when there being electric current to flow through in wire, R1 in integrating circuit recovers the current signal in wire, in integrating circuit, the voltage waveform at electric current two ends is consistent with the current waveform in wire, the amplitude of voltage and electric current have certain corresponding relation, after active differential amplifying circuit amplifies, the signal exported is added to voltage follower circuit and exports, the value exported can directly be taked by voltage table or oscillograph, the current value in wire is drawn by certain conversion relation.
Obviously, the above embodiment of the present invention is only for example of the present invention is clearly described, and is not the restriction to embodiments of the present invention.For those of ordinary skill in the field, can also make other changes in different forms on the basis of the above description.Here exhaustive without the need to also giving all embodiments.And these belong to connotation of the present invention the apparent change of extending out or variation still belong to protection scope of the present invention.
Claims (5)
1. an active faint power current inductive coil, is characterized in that, comprises flexible inductive coil, sampling and integrating circuit, active differential amplifying circuit and voltage follower; Wherein,
Flexible inductive coil, for being converted to ac current signal by the magnetic field of being coupled to and exporting sampling and integrating circuit to;
Sampling and integrating circuit, for sampling the ac current signal received, obtaining power-frequency voltage signal and exporting active differential amplifying circuit to;
Active differential amplifying circuit, exports voltage follower to after being amplified by the power-frequency voltage signal of reception;
Voltage follower, the power-frequency voltage signal for isolating, after Hyblid Buffer Amplifier, output voltage signal.
2. the active faint power current inductive coil of one according to claim 1, is characterized in that, described flexible inductive coil comprises flexible back bone, intert copper post in flexible back bone and close around two-layer wire on flexible back bone; Flexible inductive coil has two output terminals: the first output terminal and the second output terminal.
3. the active faint power current inductive coil of one according to claim 2, it is characterized in that, described flexible back bone is electrically insulating silicone rubber pipe, and described wire is soft high temperature wire.
4. the active faint power current inductive coil of one according to claim 2, it is characterized in that, described sampling and integrating circuit comprise the first resistance, the second resistance and electric capacity; Wherein,
One end of first resistance is connected respectively with one end of the second resistance, the first output terminal, and the other end of the second resistance is connected with one end of electric capacity, and the other end of the first resistance is connected respectively with the other end of the second output terminal, electric capacity.
5. the active faint power current inductive coil of one according to claim 4, it is characterized in that, described active differential amplifying circuit comprises the three to ten resistance, and voltage follower comprises the first voltage follower, the second voltage follower and tertiary voltage follower; Wherein,
One end of 3rd resistance is connected with one end of electric capacity, the other end of the 3rd resistance is connected respectively with one end of the 5th resistance, the negative input end of the first voltage follower, the positive input terminal ground connection of the first voltage follower, the output terminal of the first voltage follower is connected with one end of the 7th resistance, the other end of the 7th resistance is connected respectively with one end of the 9th resistance, the negative input end of tertiary voltage follower, and the other end of the 9th resistance is connected with the output terminal of tertiary voltage follower; One end of 4th resistance is connected with the other end of electric capacity, the other end of the 4th resistance is connected with one end of the 6th resistance, the negative input end of the second voltage follower, the positive input terminal ground connection of the second voltage follower, the other end of the 6th resistance is connected respectively with one end of the output terminal of the second voltage follower, the 8th resistance, the other end of the 8th resistance is connected respectively with one end of the positive input terminal of tertiary voltage follower, the tenth resistance, the other end ground connection of the tenth resistance.
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Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
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| CN110865230A (en) * | 2019-10-18 | 2020-03-06 | 南京信息工程大学滨江学院 | Non-contact test pencil and measurement algorithm and calibration method thereof |
| CN113075442A (en) * | 2021-03-30 | 2021-07-06 | 国网宁夏电力有限公司电力科学研究院 | Current mutual inductance circuit and current transformer |
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| CN113075442A (en) * | 2021-03-30 | 2021-07-06 | 国网宁夏电力有限公司电力科学研究院 | Current mutual inductance circuit and current transformer |
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