CN216646608U - High-voltage switch cabinet non-contact current measuring device with magnetic shielding structure - Google Patents
High-voltage switch cabinet non-contact current measuring device with magnetic shielding structure Download PDFInfo
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- CN216646608U CN216646608U CN202122600602.9U CN202122600602U CN216646608U CN 216646608 U CN216646608 U CN 216646608U CN 202122600602 U CN202122600602 U CN 202122600602U CN 216646608 U CN216646608 U CN 216646608U
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Abstract
The utility model relates to a non-contact current measuring device with a magnetic shielding structure for a high-voltage switch cabinet, which comprises a phase busbar to be measured, a busbar lantern ring, a magnetic shielding body, a TMR current sensor chip, a magnetic shielding body lantern ring, a PCB board and a guide rod, wherein the phase busbar to be measured is arranged on the phase busbar; the female row of phase place of awaiting measuring pass the internal portion of magnetism shielding, the magnetism shielding body about both ends face trompil as shielding clearance, TMR current sensor chip install wait that phase place is female arrange between the upper portion of the magnetic shielding body, TMR current sensor chip arrange the PCB board in on, the female row of phase place of awaiting measuring fixed through female the arranging the lantern ring, the magnetic shielding body pass through the magnetism shielding body lantern ring fixed, the PCB board pass through the PCB board lantern ring fixed, female row lantern ring, magnetism shielding body lantern ring, PCB board lantern ring pass through the guide arm and connect. Compared with the prior art, the method has the advantages of improving the accuracy and stability of the high-current measurement of the high-voltage switch cabinet and the like.
Description
Technical Field
The utility model relates to a non-contact current measuring device for a high-voltage switch cabinet, in particular to a non-contact current measuring device with a magnetic shielding structure for the high-voltage switch cabinet.
Background
The high-voltage switch cabinet plays roles of on-off, control or protection and the like in power generation, power transmission, power distribution, electric energy conversion and consumption of an electric power system, the high-voltage switch cabinet runs under the working condition of high voltage and large current for a long time, and in recent years, due to the requirement of high load, the current-carrying capacity of the switch cabinet is gradually increased, and the current limit value needs to be increased from 3kA to 4 kA. The improvement of the current-carrying capacity provides a new challenge for the real-time monitoring of the operation condition of the high-voltage switch cabinet, and once the switch cabinet breaks down, huge economic loss is brought to a power system. The current is used as the most important operation parameter in the power system, and the current of the equipment can be monitored in real time to ensure the safe operation of the equipment. The traditional high-voltage switch cabinet adopts a current transformer, the size is large, the cost is high, the function is single, the electromagnetic transformer is easy to generate the magnetic saturation phenomenon, and the accurate measurement of large-current monitoring can not be met. The rogowski coil monitors the magnitude of the measured current by measuring magnetomotive force, the frequency band range of the current transformer is far larger than that of a current transformer, but the current transformer can only measure time-varying current, and the current transformer is inconvenient to install and needs to be wound on a primary conductor. The Hall current sensor mainly measures current indirectly according to Hall potential generated by a current-carrying semiconductor in a magnetic field, but the measurement precision of the Hall current sensor is influenced due to large temperature rise in the switch cabinet, and the requirements of the large-current measurement range and precision cannot be met.
With the discovery and research of the magnetoresistance effect, the magnetoresistance sensor based on the magnetoresistance effect has come into play. The development of the magneto-resistance sensing technology provides a brand new technical means for large-current monitoring of the power system. Magnetoresistive sensors have evolved through four generations, mainly including hall resistance sensors, Anisotropic Magnetoresistive (AMR) sensors, Giant Magnetoresistive (GMR) sensors, Tunneling Magnetoresistive (TMR) sensors. Compared with other magneto-resistance sensors, the TMR sensor has the advantages of better temperature stability, lower power consumption, higher sensitivity, better linearity and wider linear range, does not need an additional poly magnetic ring structure or a coil structure, and is convenient to mount.
Due to the sensitivity of the TMR sensor to the magnetic field, the complex electromagnetic environment of the actual power system can directly influence the measurement precision of the TMR sensor, and further the running condition of the high-voltage switch cabinet can not be accurately monitored in real time. Therefore, a device capable of shielding the interference magnetic field and the stray magnetic field when the TMR sensor measures the phase busbar to be measured is needed.
SUMMERY OF THE UTILITY MODEL
The utility model aims to overcome the defects of the prior art and provide a non-contact current measuring device with a magnetic shielding structure for a high-voltage switch cabinet.
The purpose of the utility model can be realized by the following technical scheme:
according to one aspect of the utility model, the non-contact current measuring device with the magnetic shielding structure for the high-voltage switch cabinet comprises a phase busbar to be measured, a busbar lantern ring, a magnetic shielding body, a TMR current sensor chip, a magnetic shielding body lantern ring, a PCB board and a guide rod;
the female row of phase place of awaiting measuring pass the internal portion of magnetism shielding, the magnetism shielding body about both ends face trompil as shielding clearance, TMR current sensor chip install wait that phase place is female arrange between the upper portion of the magnetic shielding body, TMR current sensor chip arrange the PCB board in on, the female row of phase place of awaiting measuring fixed through female the arranging the lantern ring, the magnetic shielding body pass through the magnetism shielding body lantern ring fixed, the PCB board pass through the PCB board lantern ring fixed, female row lantern ring, magnetism shielding body lantern ring, PCB board lantern ring pass through the guide arm and connect.
As a preferable technical scheme, the TMR current sensor chip is a TMR7204-C series current sensor.
As a preferred technical scheme, the magnetic shielding body is made of a nickel-iron permalloy.
As the preferred technical scheme, the busbar lantern ring, the magnetic shielding body lantern ring and the PCB board lantern ring all adopt epoxy resin lantern rings.
As a preferred technical scheme, the guide rod is made of epoxy resin.
As a preferred technical scheme, the magnetic shielding body is rectangular, and the inner surface of the magnetic shielding body is parallel to the phase busbar to be detected.
Preferably, the width of the shielding gap is 4mm, the length of the magnetic shielding body is 200mm, and the thickness is 2 mm.
Preferably, the shielding gap of the magnetic shield faces the interference phase current side.
As a preferable technical scheme, the sensitive axis direction of the TMR current sensor chip is parallel to the shielding gap.
As a preferable technical scheme, the TMR current sensor chip is positioned 50mm above the phase busbar to be measured.
Compared with the prior art, the magnetic shielding structure of the switch cabinet non-contact current measuring device provided by the utility model adopts the TMR sensor to replace the traditional electromagnetic current transformer, realizes the large current monitoring of the high-voltage switch cabinet and overcomes the magnetic saturation phenomenon of the traditional electromagnetic current transformer. Meanwhile, aiming at the problem that the TMR sensor is easily influenced by an interference magnetic field, a shield body with double shielding gaps is designed, the shielding gaps play a role in collecting an induced magnetic field of interference phase large current, and the influence of an external interference magnetic field on the TMR sensor is reduced, so that the magnetic shielding structure of the switch cabinet non-contact current measuring device provided by the utility model can improve the accuracy and stability of high-current measurement of a high-voltage switch cabinet.
Drawings
FIG. 1 is a schematic structural view of the present invention;
FIG. 2 is a longitudinal cross-sectional view of the present invention;
FIG. 3 is a graph of shield uncertainty impact of shield geometry size;
FIG. 4 is a graph of gap width versus shield uncertainty;
FIG. 5 is a graph of shield length versus shield uncertainty effect;
FIG. 6 is a graph of shield thickness versus shield uncertainty;
reference numerals in the drawings, 1: a phase busbar to be detected; 2: a busbar lantern ring; 3: a magnetic shield body; 4: a TMR current sensor chip; 5: a magnetic shield collar; 6: a PCB board lantern ring; 7: a PCB board; 8: a guide rod.
Detailed Description
The technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the drawings in the embodiments of the present invention, and it is obvious that the described embodiments are some, not all, embodiments of the present invention. All other embodiments, which can be obtained by a person skilled in the art without any inventive step based on the embodiments of the present invention, shall fall within the scope of protection of the present invention.
As shown in fig. 1 and 2, a high-voltage switch cabinet non-contact current measuring device with a magnetic shielding structure comprises a phase busbar 1 to be measured, a busbar lantern ring 2, a magnetic shielding body 3, a TMR current sensor chip 4, a magnetic shielding body lantern ring 5, a PCB board lantern ring 6, a PCB board 7 and a guide rod 8;
the phase busbar 1 to be tested penetrates through the center of the magnetic shielding body 3, the other two-phase interference current busbar 9 is respectively positioned at two sides of the magnetic shielding body 3, shielding gaps are respectively formed at two sides of the magnetic shielding body 3, and the shielding gaps face the other two-phase interference current busbar 9.
TMR current sensor chip 4 install and wait to await measuring the phase place and arrange between the upper portion of 1 and the magnetic shield body 3, TMR current sensor chip 4 arrange PCB board 7 in on, wait to await measuring the phase place and arrange 1 fixed through female the arranging lantern ring 2, the magnetic shield body 3 fixed through the magnetic shield body lantern ring 5, PCB board 7 fixed through PCB board lantern ring 6, female arranging lantern ring 2, the magnetic shield body lantern ring 5, PCB board lantern ring 6 of arranging connect through guide arm 8.
The TMR current sensor chip 4 is a TMR7204-C series current sensor. When the TMR current sensor chip is used, the magnetic shielding body 3 with the double shielding gaps plays a role of magnetic shielding, the induced magnetic field of large interference phase current is gathered at the shielding gaps, the influence of the external interference magnetic field on the TMR current sensor chip 4 can be reduced, and the measurement accuracy and the reliability of the TMR current sensor chip 4 are improved.
The magnetic shielding body 3 is made of a nickel-iron permalloy. The busbar lantern ring 2, the magnetic shielding body lantern ring 5 and the PCB lantern ring 6 are all epoxy resin lantern rings. The guide rod 8 is made of epoxy resin. The lantern ring and the guide rod are made of epoxy resin to ensure insulativity.
The magnetic shielding body 3 is rectangular, and the inner surface of the magnetic shielding body is parallel to the phase busbar 1 to be tested. The width of the shielding gap is 4mm, the length of the magnetic shielding body 3 is 200mm, and the thickness is 2 mm. The shielding gap of the magnetic shield 3 faces the interference phase current side. The sensing axis direction of the TMR current sensor chip 4 is parallel to the shielding gap. The sensitive axis of the MR current sensor chip 4 senses the electromagnetic component of the busbar to be measured in the direction, and the internal wheatstone bridge generates a bias voltage and outputs a current to be measured at the output end. And the TMR current sensor chip 4 is positioned 50mm above the phase busbar 1 to be detected.
Finite element analysis
In order to verify the effectiveness of the utility model, simulation analysis software based on a finite element analysis method is adopted to verify the effectiveness of the utility model, and a simulation model simplifies a fixed supporting structure and hardly influences the calculation result of the magnetic field.
The current value of stable operation is 3000A, firstly, the simulation results of the non-interference current and the non-magnetic shielding structure are compared, and the simulation results are the magnetic field and the magnetic flux density components measured in the sensitive axis direction of the sensor, as shown in Table 1:
TABLE 1
| Simulated working conditions | Magnetic field, x component (A/m) | Magnetic flux density, x component (G) |
| No magnetic shielding and no interference current | 7143.92 | 89.77 |
| Magnetic shielding and no interference of current | 6920.97 | 86.97 |
| No magnetic shielding and interference current | 7409.97 | 93.12 |
| With magnetic shielding and interference current | 7166.10 | 90.05 |
As can be seen from table 1, the magnetic field and the magnetic flux density component measured by the sensor are larger when there is interference current than when there is no interference current, because the magnetic field superposition effect, the magnetic field induced by other two-phase current affects the measurement value of the sensor, and finally affects the accuracy of current measurement; after the magnetic shielding structure is additionally arranged, the shielding structure can effectively shield an interference magnetic field generated by an interference phase, so that the magnetic field and the magnetic flux density component measured by the sensor are closer to the true value.
Subsequently, in order to further increase the magnetic shielding effectiveness of the magnetic shielding structure, the magnetic shielding device of the present invention was structurally improved by parametric studies.
Firstly, when the effectiveness of the structure is evaluated, the Shielding effectiveness is not adopted in the simulation, but the Shielding Uncertainty (SU) is adopted to describe the detection result of the TMR sensor when a non-interference magnetic field exists. The magnetic shield uncertainty is defined as follows:
wherein, BrIs the magnetic flux density detected by the TMR sensor after shielding in the presence of interference current, B0Is the magnetic flux density detected by the TMR sensor after shielding without interference current. A smaller SU indicates a more effective magnetic shielding structure.
The utility model designs the shielding body with double shielding gaps, the shielding gaps play a role of collecting an induced magnetic field of large current of an interference phase, and the influence of an external interference magnetic field on the TMR sensor can be reduced. Therefore, the influence of the size of the shielding gap on the magnetic shielding effectiveness is researched through simulation parameterization, and the influence of the width of the shielding gap and the thickness and the length of the shielding body on the uncertainty of the magnetic shielding is respectively analyzed, and the simulation results are shown in the following table 2 and fig. 3-6:
TABLE 2
As can be seen from table 2, the magnetic shield with double shielding gaps has lower shielding uncertainty and better shielding effect than the magnetic shield without shielding gaps in a reasonable structural size.
As can be seen from fig. 3-6, the magnetic shielding uncertainty decreases with increasing length of the shield and width of the shield gap, and decreases with increasing thickness of the shield.
Considering the influence of three structural dimensions comprehensively, as can be seen from fig. 3-6, the influence of the thickness of the shield on the shield uncertainty is the largest, and the influence of the length and the gap width is the smallest; considering the cost and the magnetic shielding effect comprehensively, when the length of the shielding body is 200mm, the thickness is 2mm, and the width of the shielding gap is 4mm, the shielding uncertainty is minimum and is 3.81%.
While the utility model has been described with reference to specific embodiments, the utility model is not limited thereto, and various equivalent modifications and substitutions can be easily made by those skilled in the art within the technical scope of the utility model. Therefore, the protection scope of the present invention shall be subject to the protection scope of the claims.
Claims (10)
1. A high-voltage switch cabinet non-contact current measuring device with a magnetic shielding structure is characterized by comprising a phase bus bar (1) to be measured, a bus bar lantern ring (2), a magnetic shielding body (3), a TMR current sensor chip (4), a magnetic shielding body lantern ring (5), a PCB board lantern ring (6), a PCB board (7) and a guide rod (8);
wait that phase place that awaits measuring female arranging (1) pass inside magnetic shield body (3), magnetic shield body (3) control both ends face trompil as shielding clearance, TMR current sensor chip (4) install and wait to wait that phase place is female arranges between the upper portion of (1) and magnetic shield body (3), TMR current sensor chip (4) arrange in on PCB board (7), wait that phase place is female arranges (1) and fixes through female the arranging lantern ring (2), magnetic shield body (3) fixed through magnetic shield body lantern ring (5), PCB board (7) fixed through PCB board lantern ring (6), female arranging lantern ring (2), magnetic shield body lantern ring (5), PCB board lantern ring (6) and connect through guide arm (8).
2. The non-contact current measuring device with the magnetic shielding structure for the high-voltage switch cabinet according to claim 1, characterized in that the TMR current sensor chip (4) is a TMR7204-C series current sensor.
3. The non-contact current measuring device with the magnetic shielding structure for the high-voltage switch cabinet is characterized in that the magnetic shielding body (3) is made of permalloy.
4. The high-voltage switch cabinet non-contact current measuring device with the magnetic shielding structure according to claim 1, wherein the busbar lantern ring (2), the magnetic shielding body lantern ring (5) and the PCB board lantern ring (6) are all epoxy resin lantern rings.
5. The non-contact current measuring device with the magnetic shielding structure for the high-voltage switch cabinet according to claim 1, wherein the guide rod (8) is made of epoxy resin.
6. The non-contact current measuring device with the magnetic shielding structure for the high-voltage switch cabinet according to claim 1, wherein the magnetic shielding body (3) is rectangular, and the inner surface of the magnetic shielding body is parallel to the phase busbar (1) to be measured.
7. The non-contact current measuring device with the magnetic shielding structure for the high-voltage switch cabinet is characterized in that the width of the shielding gap is 4mm, the length of the magnetic shielding body (3) is 200mm, and the thickness of the magnetic shielding body is 2 mm.
8. The non-contact current measuring device with the magnetic shielding structure for the high-voltage switch cabinet according to claim 1, characterized in that the shielding gap of the magnetic shielding body (3) faces the current side of the interference phase.
9. The non-contact current measuring device with the magnetic shielding structure for the high-voltage switch cabinet according to claim 1, characterized in that the sensitive axis direction of the TMR current sensor chip (4) is parallel to the shielding gap.
10. The non-contact current measuring device with the magnetic shielding structure for the high-voltage switch cabinet according to claim 1, wherein the TMR current sensor chip (4) is located 50mm above the phase busbar (1) to be measured.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202122600602.9U CN216646608U (en) | 2021-10-28 | 2021-10-28 | High-voltage switch cabinet non-contact current measuring device with magnetic shielding structure |
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| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202122600602.9U CN216646608U (en) | 2021-10-28 | 2021-10-28 | High-voltage switch cabinet non-contact current measuring device with magnetic shielding structure |
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| Publication Number | Publication Date |
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| CN216646608U true CN216646608U (en) | 2022-05-31 |
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| CN202122600602.9U Active CN216646608U (en) | 2021-10-28 | 2021-10-28 | High-voltage switch cabinet non-contact current measuring device with magnetic shielding structure |
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