CN112881780A - Array passive lightning current sensor - Google Patents
Array passive lightning current sensor Download PDFInfo
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- CN112881780A CN112881780A CN202110072456.9A CN202110072456A CN112881780A CN 112881780 A CN112881780 A CN 112881780A CN 202110072456 A CN202110072456 A CN 202110072456A CN 112881780 A CN112881780 A CN 112881780A
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- lightning current
- magnetoelectric
- current sensor
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- pipe
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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
- G01R19/0046—Arrangements for measuring currents or voltages or for indicating presence or sign thereof characterised by a specific application or detail not covered by any other subgroup of G01R19/00
- G01R19/0053—Noise discrimination; Analog sampling; Measuring transients
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- G—PHYSICS
- G01—MEASURING; TESTING
- G01R—MEASURING ELECTRIC VARIABLES; MEASURING MAGNETIC VARIABLES
- G01R1/00—Details of instruments or arrangements of the types included in groups G01R5/00 - G01R13/00 and G01R31/00
- G01R1/02—General constructional details
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- G—PHYSICS
- G01—MEASURING; TESTING
- G01R—MEASURING ELECTRIC VARIABLES; MEASURING MAGNETIC VARIABLES
- G01R15/00—Details of measuring arrangements of the types provided for in groups G01R17/00 - G01R29/00, G01R33/00 - G01R33/26 or G01R35/00
- G01R15/14—Adaptations providing voltage or current isolation, e.g. for high-voltage or high-current networks
- G01R15/20—Adaptations providing voltage or current isolation, e.g. for high-voltage or high-current networks using galvano-magnetic devices, e.g. Hall-effect devices, i.e. measuring a magnetic field via the interaction between a current and a magnetic field, e.g. magneto resistive or Hall effect devices
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- General Physics & Mathematics (AREA)
- Measuring Instrument Details And Bridges, And Automatic Balancing Devices (AREA)
Abstract
The invention discloses an array type passive lightning current sensor which comprises a U-shaped pipe, wherein the upper end of the U-shaped pipe is detachably connected with a sealing cover pipe, and the sealing cover pipe and the U-shaped pipe form a symmetrical annular structure; a plurality of abutting blocks are arranged on the adjacent side surfaces of the outer side wall of the U-shaped pipe and the sealing cover pipe; a plurality of magnetoelectric structures are uniformly distributed in the annular structure; the magnetoelectric structure comprises two mutually overlapped magnetostrictive sheets, and a piezoelectric sheet is arranged in the middle of each magnetostrictive sheet. The invention can solve the problems of insufficient accuracy and poor response speed of the device for measuring outdoor lightning current in the prior art, and can complete measurement without an external power supply; the problem that the existing detachable structure cannot be detached after installation is solved by using the opening-closing type detachable structure; the sensor performance is improved by using the array structure; simple structure, strong reliability and good accuracy.
Description
Technical Field
The invention relates to a current measuring device, in particular to an array type passive lightning current sensor.
Background
For an electrical facility fixedly arranged outdoors, lightning current is a main factor influencing the normal operation of a line, so that the measurement of the lightning current is particularly critical for reducing the influence of the lightning current. The lightning current belongs to microsecond-level pulse current, so that higher requirements on the measurement accuracy of the sensor are met.
The rogowski coil is a current sensor based on the electromagnetic induction principle, and is the most widely applied transient current sensor at present. The structure of the device mainly comprises a coil and an integral loop.
The method has the advantages that the accuracy of measuring lightning current by using the Rogowski coil is high, but the cost of the whole detection system is high, the amplitude of an induction signal is low, and the response speed is poor; the integrator requires a high precision on the resistors in order to maintain good stability. The rogowski coil requires an external power source to operate.
The rogowski coil with the magnetic core has higher sensitivity, but magnetic saturation is easy to achieve, and the magnetic core is usually very large for preventing the generation of saturation, so that the sensor has a large structure, heavy weight, difficult installation and maintenance and the like.
The coil without the magnetic core is small in size and light in weight, but low-frequency distortion is easily generated due to the fact that self-integration conditions of the coil are insufficient. And the Rogowski coil needs an external power supply to supply power when working, so that the Rogowski coil is not easy to install and maintain.
Disclosure of Invention
Aiming at the defects in the prior art, the invention provides the array type passive lightning current sensor which can solve the problems of insufficient accuracy and poor response speed of an outdoor lightning current measuring device in the prior art.
In order to solve the technical problems, the invention adopts the following technical scheme:
the array type passive lightning current sensor comprises a U-shaped pipe, wherein the upper end of the U-shaped pipe is detachably connected with a sealing cover pipe, and the sealing cover pipe and the U-shaped pipe form a symmetrical annular structure;
a plurality of abutting blocks are arranged on the adjacent side surfaces of the outer side wall of the U-shaped pipe and the sealing cover pipe;
a plurality of magnetoelectric structures are uniformly distributed in the annular structure;
the magnetoelectric structure comprises two mutually overlapped magnetostrictive sheets, and a piezoelectric sheet is arranged in the middle of each magnetostrictive sheet.
The array passive lightning current sensor provided by the invention has the main beneficial effects that:
according to the invention, by arranging the magnetoelectric structure, when lightning current passes through the lead, an annular magnetic field is formed around the lead, the magnetostrictive sheet on the magnetoelectric structure is deformed under the action of the magnetic field, the deformation is increased along with the increase of the magnetic field, and the deformation is transmitted to the piezoelectric sheet through interface coupling, the piezoelectric sheet generates polarization along the thickness direction due to the deformation, so that potential difference is generated on the upper end surface and the lower end surface of the piezoelectric sheet, and the measurement of the lightning current or the pulse current can be realized by outputting the potential difference and processing signals without an external power supply, so that the energy is saved, and the installation is convenient and flexible; and because the directly measured potential difference is far smaller than the instantaneous current peak value on the wire, the measuring equipment can be effectively prevented from being broken down by the current, and the effectiveness and the accuracy of the measurement are ensured.
A plurality of magnetoelectric structures are arranged in the U-shaped pipe and the sealing cover pipe to form an array layout and are positioned on a circle concentric with the conducting wire, and the distances between the magnetoelectric structures and the conducting wire are equal, so that the sensed magnetic field intensity is equal, and the electric potential generated by the electromechanical coupling of the magnet is equal in theory.
In actual measurement, the output voltage of each magnetoelectric structure is averaged after being processed, so that the measurement of pulse current can be completed, and the measurement accuracy of the sensor is improved by considering error factors of different positions, such as eccentric error and the like.
And because the cover sealing pipe and the U-shaped pipe are of a detachable structure, the device can be conveniently installed at any position of a wire to be measured, the best measuring effect is effectively ensured, and the limitation of insufficient accuracy and reliability caused by the limitation of the installation position is avoided. Simultaneously, through setting up the structure of convenient dismantlement, the later maintenance of still being convenient for.
Drawings
Fig. 1 is a schematic structural view of the present invention.
Fig. 2 is a cross-sectional view of the present invention.
Fig. 3 is a graph of magnetic flux density comparison of an array structure and a single magnetoelectric structure.
The device comprises a ring structure 1, an annular structure 11, a U-shaped pipe 12, a cover pipe 13, a buckle 14, a flange 15, an abutting block 16, a support 2, a magnetoelectric structure 21, a magnetostrictive sheet 22, a piezoelectric sheet 3 and a lead.
Detailed Description
The invention will be further described with reference to the accompanying drawings in which:
fig. 1 is a schematic structural diagram of an array-type passive lightning current sensor.
The array type passive lightning current sensor comprises a U-shaped pipe 11, wherein the upper end of the U-shaped pipe 11 is detachably connected with a sealing cover pipe 12, and the sealing cover pipe 12 and the U-shaped pipe 11 form a symmetrical annular structure 1. Through the combination of split into U-shaped pipe 11 and closing cap pipe 12 with the sensor to place wire 3 in the cavity between U-shaped pipe 11 and closing cap pipe 12, reduce the distance between wire 3 and the measurement structure, improve measurement accuracy.
Optionally, the ring structure 1 is a square structure with rounded corners to facilitate installation of the internal structure.
The outer side wall of the U-shaped pipe 11 and the adjacent side surface of the cover pipe 12 are provided with a plurality of abutting blocks 15, and the abutting blocks 15 are connected with the lead 3 in a matching mode.
As shown in fig. 2, a plurality of magnetoelectric structures 2 are uniformly distributed inside the ring-shaped structure 1. The magnetoelectric structure 2 includes two magnetostrictive sheets 21 that overlap each other, and a piezoelectric sheet 22 is disposed between the magnetostrictive sheets 21. The magnetostrictive sheet 21 is made of a magnetostrictive material, and the piezoelectric sheet 22 is made of a piezoelectric material.
Preferably, the magnetostrictive sheet 21 and piezoelectric sheet 22 are the same length to ensure the accuracy of the measurement.
Specifically, the magnetoelectric structures 2 are in the shape of bars. The number of the magnetoelectric structures 2 is four, three of the magnetoelectric structures are positioned in the U-shaped tube 11, and the other one is positioned in the cover tube 12; the adjacent magnetoelectric structures 2 are perpendicular to each other to ensure the accuracy of the measurement structure and reduce errors caused by position and angle factors.
The upper and lower end faces of the piezoelectric sheet 22 are connected to the outside through leads, respectively, to output a potential difference.
The magnetoelectric structures 2 are fixedly arranged on the side walls of the U-shaped tube 11 and the cover tube 12 which are positioned on the outer sides through the support 16, and the distances from each magnetoelectric structure 2 to the central axis of the annular structure 1 are equal. I.e. each magnetoelectric structure 2 is located on a concentric circle on which the central axis of one ring-shaped structure 1 is located, whereby the potential differences generated between each magnetoelectric structure 2 are theoretically the same value.
The magnetostrictive sheet 21 and the piezoelectric sheet 22 are bonded through a non-conductive colloid material, so that the correlation between the change of the piezoelectric sheet 22 and the instantaneous current of the lead 4 is avoided, and the measurement accuracy is ensured.
The abutting blocks 15 are four in total and correspond to the positions of the magnetoelectric structures 2. The abutting block 15 is of an annular structure made of rubber materials so as to adapt to the wires 3 with different sizes and ensure the stability of clamping.
The cover tube 12 is provided with a buckle 13, and the U-shaped tube 11 is provided with a flange 14 matched with the buckle 13, so that the cover tube 12 and the U-shaped tube 11 can be detachably connected.
The U-shaped pipe 1 is made of aluminum materials, so that an external electric field is shielded, a magnetic field can be normally distributed, and the influence on measurement is avoided.
The following is a description of the working principle of the present invention:
the magnetoelectric effect of the magnetoelectric structure 2 can be expressed as:
MEeffect＝(electric/mechanical)*(mechanical/magnetic)，
wherein ME is a magnetoelectric materialeffctFor its corresponding magnetoelectric effect, electric is the effect of the current, mechanical is the effect of the mechanical deformation and magnetic is the effect of the magnetism, whereby for a particular magnetoelectric material, in MEeffctIn the fixed case, the larger the instantaneous current, the stronger the magnetic field generated.
When lightning current or pulse current flows on the lead 4, an annular magnetic field is formed around the lead 4, the magnetostrictive sheet 21 on the magnetoelectric structure 2 deforms under the action of the magnetic field, the deformation is increased along with the increase of the magnetic field, and the deformation is transmitted to the piezoelectric sheet 21 through interface coupling, the piezoelectric sheet 21 changes in shape due to the difference in deformation of the upper side edge and the lower side edge, and then polarization along the thickness direction is generated, so that potential difference is generated on the upper end surface and the lower end surface of the piezoelectric sheet 21.
The lightning current belongs to transient pulse current, and the whole waveform is divided into a rising area and a falling area. When the lightning current is in a rising area, the magnetic field around the lead 4 is increased, and the output voltage of the sensor is increased; when the lightning current reaches a peak value, the output voltage of the sensor also reaches a maximum value; the lightning current is in a descending area, the magnetic field around the lead 4 is reduced, and the output voltage of the sensor is reduced accordingly. The output potential difference of the magnetoelectric structure 2 can change along with the current and change along with the lightning current waveform, so that the measurement of the lightning current or the pulse current can be realized by outputting the potential difference and processing signals.
The four magnetoelectric structures 2 are arranged around the current-carrying lead wire 3 in an array shape and are positioned on a circle concentric with the lead wire 3, and the distances between the four magnetoelectric structures 2 and the lead wire 3 are equal, so that the sensed magnetic field intensity is equal, and the electric potential generated by the electromechanical coupling of the magnetism is equal in theory.
In actual measurement, the output voltages of the four magnetoelectric structures 2 are processed and then averaged, so that the measurement of pulse current can be completed, and the measurement accuracy of the sensor is remarkably improved by considering error factors of different positions, such as eccentric errors and the like.
The principle of improving the measurement precision is as follows:
the magnetic flux phi is obtained by the magnetic path theorem phi of F/Rm, and the smaller the magnetic resistance Rm is, the larger the magnetic flux phi is when the magnetomotive force F is constant. Because in the same magnetic circuit, the magnetic conductivity of the magnetoelectric structure 2 is far greater than that of air, and the magnetic resistance and the magnetic conductivity are reciprocal, the magnetic resistance of the air is far greater than that of the magnetoelectric structure 2.
Therefore, the array arrangement of the plurality of magnetoelectric structures 2 can improve the magnetic flux thereon, and the magneto-electromechanical-coupling mechanism of the array arrangement has higher conversion efficiency.
The single magnetoelectric structure 2 and the four magnetoelectric structures 2 are arranged in an array manner and tested to obtain the result shown in fig. 3, so that the sensitivity of the sensor can be improved by the array type structure.
Further, because the directly measured potential difference is far smaller than the instantaneous current peak value on the wire 3, the measuring equipment can be effectively prevented from being broken down by the current, and the effectiveness and the accuracy of the measurement are ensured.
The above description of the embodiments of the present invention is provided to facilitate the understanding of the present invention by those skilled in the art, but it should be understood that the present invention is not limited to the scope of the embodiments, and it will be apparent to those skilled in the art that various changes may be made without departing from the spirit and scope of the invention as defined and defined in the appended claims, and all matters produced by the invention using the inventive concept are protected.
Claims (10)
1. An array type passive lightning current sensor is characterized by comprising a U-shaped pipe, wherein the upper end of the U-shaped pipe is detachably connected with a sealing cover pipe, and the sealing cover pipe and the U-shaped pipe form a symmetrical annular structure;
a plurality of abutting blocks are arranged on the adjacent side surfaces of the outer side wall of the U-shaped pipe and the sealing cover pipe;
a plurality of magnetoelectric structures are uniformly distributed in the annular structure;
the magnetoelectric structure comprises two mutually overlapped magnetostrictive sheets, and a piezoelectric sheet is arranged in the middle of each magnetostrictive sheet.
2. The array passive lightning current sensor of claim 1, wherein the magnetoelectric structure is in the form of a strip.
3. The array passive lightning current sensor of claim 2, wherein four of the magnetoelectric structures are located, three of the magnetoelectric structures are located in the U-shaped tube, and the other one of the magnetoelectric structures is located in the capping tube; the adjacent magnetoelectric structures are perpendicular to each other.
4. The array passive lightning current sensor of claim 1, wherein the upper and lower end surfaces of the piezoelectric plate are respectively connected to the outside through leads.
5. The array passive lightning current sensor of claim 4, wherein the magneto-electric structures are fixedly arranged on the outer side walls of the U-shaped tube and the cover tube through a bracket, and the distance from each magneto-electric structure to the central axis of the ring-shaped structure is equal.
6. The array passive lightning current sensor of claim 5, wherein the magnetostrictive sheet and piezoelectric sheet are bonded together by a non-conductive adhesive material.
7. The array passive lightning current sensor of claim 3, wherein the number of the abutting blocks is four and corresponds to the positions of the magnetoelectric structures.
8. The array passive lightning current sensor of claim 7, wherein the abutment block is a ring structure of rubber.
9. The array passive lightning current sensor of claim 1, wherein the cover tube is provided with a snap and the U-shaped tube is provided with a flange for engaging the snap.
10. The array passive lightning current sensor of claim 1, wherein the U-shaped tube is made of aluminum.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202110072456.9A CN112881780A (en) | 2021-01-20 | 2021-01-20 | Array passive lightning current sensor |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202110072456.9A CN112881780A (en) | 2021-01-20 | 2021-01-20 | Array passive lightning current sensor |
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| Publication Number | Publication Date |
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| CN112881780A true CN112881780A (en) | 2021-06-01 |
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| Application Number | Title | Priority Date | Filing Date |
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| CN202110072456.9A Pending CN112881780A (en) | 2021-01-20 | 2021-01-20 | Array passive lightning current sensor |
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Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN116500320A (en) * | 2023-06-28 | 2023-07-28 | 广东电网有限责任公司珠海供电局 | Injection current probe for cable fault detection |
Citations (5)
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| US20050134253A1 (en) * | 2003-04-10 | 2005-06-23 | Kovanko Thomas E. | Current sensor |
| US20050156587A1 (en) * | 2004-01-16 | 2005-07-21 | Fieldmetrics Inc. | Current sensor |
| CN101369484A (en) * | 2008-05-28 | 2009-02-18 | 中国科学院上海硅酸盐研究所 | Non-contact type current/voltage converter |
| CN106908634A (en) * | 2017-03-29 | 2017-06-30 | 清华大学 | A kind of AC current sensor based on magnetoelectricity laminate with c-type magnet ring |
| CN109425775A (en) * | 2017-08-25 | 2019-03-05 | 南京理工大学 | A kind of hand-held current sensor using magnetic electric compound material |
-
2021
- 2021-01-20 CN CN202110072456.9A patent/CN112881780A/en active Pending
Patent Citations (5)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US20050134253A1 (en) * | 2003-04-10 | 2005-06-23 | Kovanko Thomas E. | Current sensor |
| US20050156587A1 (en) * | 2004-01-16 | 2005-07-21 | Fieldmetrics Inc. | Current sensor |
| CN101369484A (en) * | 2008-05-28 | 2009-02-18 | 中国科学院上海硅酸盐研究所 | Non-contact type current/voltage converter |
| CN106908634A (en) * | 2017-03-29 | 2017-06-30 | 清华大学 | A kind of AC current sensor based on magnetoelectricity laminate with c-type magnet ring |
| CN109425775A (en) * | 2017-08-25 | 2019-03-05 | 南京理工大学 | A kind of hand-held current sensor using magnetic electric compound material |
Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN116500320A (en) * | 2023-06-28 | 2023-07-28 | 广东电网有限责任公司珠海供电局 | Injection current probe for cable fault detection |
| CN116500320B (en) * | 2023-06-28 | 2023-09-22 | 广东电网有限责任公司珠海供电局 | Injection current probe for cable fault detection |
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