CN219800651U - Current transformer - Google Patents
Current transformer Download PDFInfo
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- CN219800651U CN219800651U CN202321368900.2U CN202321368900U CN219800651U CN 219800651 U CN219800651 U CN 219800651U CN 202321368900 U CN202321368900 U CN 202321368900U CN 219800651 U CN219800651 U CN 219800651U
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- 238000004804 winding Methods 0.000 claims abstract description 16
- 230000005672 electromagnetic field Effects 0.000 claims abstract description 7
- 238000007789 sealing Methods 0.000 claims abstract description 5
- 239000000853 adhesive Substances 0.000 claims abstract description 4
- 230000001070 adhesive effect Effects 0.000 claims abstract description 4
- 239000010410 layer Substances 0.000 claims description 13
- RYGMFSIKBFXOCR-UHFFFAOYSA-N Copper Chemical compound [Cu] RYGMFSIKBFXOCR-UHFFFAOYSA-N 0.000 claims description 8
- 239000002356 single layer Substances 0.000 claims description 4
- 230000000149 penetrating effect Effects 0.000 claims description 3
- 230000005674 electromagnetic induction Effects 0.000 abstract description 6
- 238000005259 measurement Methods 0.000 description 18
- 230000005291 magnetic effect Effects 0.000 description 9
- XEEYBQQBJWHFJM-UHFFFAOYSA-N Iron Chemical group [Fe] XEEYBQQBJWHFJM-UHFFFAOYSA-N 0.000 description 8
- 239000004020 conductor Substances 0.000 description 3
- 238000010586 diagram Methods 0.000 description 3
- 238000005516 engineering process Methods 0.000 description 3
- 238000009413 insulation Methods 0.000 description 3
- 238000012423 maintenance Methods 0.000 description 3
- 230000000737 periodic effect Effects 0.000 description 3
- 238000009434 installation Methods 0.000 description 2
- 238000004519 manufacturing process Methods 0.000 description 2
- 229920006395 saturated elastomer Polymers 0.000 description 2
- 230000009286 beneficial effect Effects 0.000 description 1
- 230000015556 catabolic process Effects 0.000 description 1
- 238000006243 chemical reaction Methods 0.000 description 1
- 238000010276 construction Methods 0.000 description 1
- 230000008878 coupling Effects 0.000 description 1
- 238000010168 coupling process Methods 0.000 description 1
- 238000005859 coupling reaction Methods 0.000 description 1
- 230000007547 defect Effects 0.000 description 1
- 238000001514 detection method Methods 0.000 description 1
- 230000000694 effects Effects 0.000 description 1
- 238000004880 explosion Methods 0.000 description 1
- 239000002360 explosive Substances 0.000 description 1
- 238000000605 extraction Methods 0.000 description 1
- 230000005294 ferromagnetic effect Effects 0.000 description 1
- 230000005350 ferromagnetic resonance Effects 0.000 description 1
- 230000006698 induction Effects 0.000 description 1
- 238000000034 method Methods 0.000 description 1
- 230000010355 oscillation Effects 0.000 description 1
- 230000001052 transient effect Effects 0.000 description 1
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- Measuring Instrument Details And Bridges, And Automatic Balancing Devices (AREA)
- Transformers For Measuring Instruments (AREA)
Abstract
The utility model discloses a current transformer, which comprises a base, 2 or more than 2 sensing coils with even numbers, wherein the top end of the base is provided with an accommodating groove; each sensing coil is made into a frame structure by hollow winding of an insulating wire, all the sensing coils are symmetrically distributed around the hollow center respectively, and the sensing coils which are coaxially distributed are parallel after being connected in series or arranged in the same axis, are arranged in a containing groove of a base and are sealed by an insulating adhesive sealing cover; the configuration of all the sensing coils enables the superposition of induced electromotive forces caused by a common electromagnetic field in all the sensing coils to cancel each other out, and two ends are reserved as output signal ends; when the electromagnetic induction device is used, the end face of the current transformer accommodating groove sealing cover is only required to be attached to a tested power system, and after the measuring angle is adjusted, electromagnetic signals can be effectively measured no matter strong electromagnetic induction signals or weak electromagnetic induction signals can pass through the hollow inner cavity of the sensing coil, and the electromagnetic induction device has the characteristics of high precision, good linearity and strong electromagnetic interference resistance.
Description
[ field of technology ]
The utility model belongs to the current transformer technology, and particularly relates to a current transformer.
[ background Art ]
At present, the current transformer is mainly an electromagnetic current transformer, which is composed of an iron core and a primary winding and a secondary winding, and has the main defects that: 1. the insulation structure is complex, the size is large, and the manufacturing cost is high; 2. the measurement accuracy cannot be met, and as the primary coil and the high-voltage bus are equipotential, the secondary coil is connected with secondary low-voltage equipment at the low-voltage side, and the coils between the primary coil and the secondary low-voltage equipment are connected by virtue of the iron core; with the increase of the voltage level, the insulation distance between the high voltage and the low voltage is correspondingly increased; at this time, the connection of the primary coil and the secondary coil can be enhanced only by a method of increasing the magnetic circuit; since the measurement error is proportional to the average magnetic path length of the transformer, the measurement error increases while the magnetic path is being lengthened. The output power of the secondary side of the traditional electromagnetic current transformer is larger and generally reaches several watts, and the primary side is influenced by the secondary side due to direct electromagnetic connection of the primary side and the secondary side, and the factors can influence the measurement accuracy of the current transformer; the accuracy of the current transformers for measurement used in power systems is mostly limited to the 0.3 level; under the transient fault current condition, the measurement accuracy is also affected by the fact that the iron core is saturated by the non-periodic component current; 3. the equipment is inconvenient to install and overhaul, and the maintenance workload is large. Because the electromagnetic current transformer has huge volume and heavy weight, the transportation and the installation are very inconvenient, and the electromagnetic current transformer needs to be supported by an insulating bracket during normal operation, thereby correspondingly bringing inconvenience to maintenance; 4. the potential danger exists, and the energy transfer is realized between the first and second times of the electromagnetic current transformer by the electromagnetic conversion principle, so that the electromagnetic connection exists between the first and second times; if the secondary coil is open-circuited for some reason, the large current at the primary side becomes exciting current completely, high voltage is induced at the secondary coil side, and the safety of personnel and equipment is endangered; there are also unstable factors of the system such as a single-phase to ground short circuit caused by sudden explosion and insulation breakdown; 5. in addition, the conventional electromagnetic current transformer also has factors such as ferromagnetic resonance and hysteresis effect which are unfavorable for measurement. In particular, the iron core of the electromagnetic current transformer is a nonlinear element, and once the iron core is saturated, the secondary current is severely distorted, while in an ultra-high voltage power system, the primary system short-circuit current has a large value and contains a large number of periodic components, and particularly, the situation that the non-periodic component is the largest value is most serious.
The electronic current transformer based on the air-core coil has the advantages of small volume, light weight, low manufacturing cost, no iron core, large dynamic response range and wide frequency response, and does not have the problems of magnetic saturation and ferromagnetic oscillation. However, in the current sensor heads of the air coils of the current transformers, the primary straight conductor directly passes through the center of a non-magnetic annular skeleton around which the secondary coil is wound, or the secondary coil is manufactured on a Printed Circuit Board (PCB) with a hollow center, and the primary straight conductor passes through the center of the PCB. These two air-core coil current sensors have two main disadvantages: (1) The coupling between the primary conductor and the secondary coil is weaker, so that the mutual inductance coefficient is smaller, the mutual inductance coefficient is difficult to improve by increasing the number of turns and the area of the coil, otherwise, the resistance, the area and the volume of the coil are increased; (2) is susceptible to external interference magnetic fields; in addition, the annular framework is inconvenient for uniformly and tightly winding the sensing coil, so that the measurement precision and the electromagnetic interference resistance are also affected. Because of the above drawbacks, when the existing air-core coil current sensing technology is used for three-phase current measurement of a power system, the current measurement of one phase is interfered by electromagnetic fields generated by other two phases of currents, particularly when small currents (light loads of the power system) are measured, the induction signals are weak, and the current measurement is easily interfered by external magnetic fields, so that the measurement error is larger.
[ utility model ]
The embodiment of the utility model provides the current transformer which has high precision, good linearity, strong electromagnetic interference resistance and convenient detection, and can be used for measuring only by being attached to a tested power system and adjusting a measuring angle, thereby being simple and convenient.
The technical scheme adopted by at least one embodiment of the utility model is as follows:
a current transformer, comprising:
the top end of the base is provided with an accommodating groove;
the sensing coils are arranged in parallel after being connected in series or arranged in the same axis, are arranged in a containing groove of a base and are sealed by an insulating adhesive sealing cover;
all the sensing coils are configured so that the superposition of induced electromotive forces caused in all the sensing coils by a common electromagnetic field cancel each other out, and the two ends are reserved as output signal ends.
Preferably, the sensing coils are all made of the same insulated wire and uniformly and densely wound into a multi-turn single-layer or multi-layer frame winding structure in a hollow center, and the shape, the size, the number of layers of the coils and the number of turns of each layer of the sensing coils are the same.
Preferably, the sensing coil is hollow wound by adopting the same insulated copper wire to form a single-turn or multi-turn single-layer or multi-turn multi-layer frame winding structure.
Preferably, the sensing coil is a flat square winding structure or a flat elliptic winding structure.
Preferably, the number of turns of the sensing coil is 20-2000.
Preferably, the insulated wire in the sensing coil is an insulated copper wire, and the diameter of the insulated copper wire is 0.05-lmm.
Preferably, the base is a cylinder with an I-shaped structure, a circular accommodating groove with an open top surface is formed in the top end of the cylinder, and a signal leading-out channel which is convenient for leading out two output signal ends of all the sensing coils from the bottom end is formed in the axial center of the cylinder in a penetrating way.
The embodiment of the utility model has the beneficial effects that:
the current sensor aims at solving the problems that the existing current sensor is easy to saturate, slow in response, poor in linearity and low in electromagnetic interference resistance, and the current sensor needs to be symmetrically wound on a tested power system during measurement, so that measurement is inconvenient.
The utility model adopts the current sensor of the air-core coil, has no iron core, has the characteristics of wide frequency band and quick response, and can effectively measure no matter strong or weak electromagnetic induction signals; moreover, the current sensors adopting the air coils are connected in series in a limited mode, and the configuration of the current sensors enables the superposition of induced electromotive forces caused by a common electromagnetic field in all the sensing coils to be mutually offset, so that the interference of an external magnetic field is eliminated, an electromagnetic shielding layer is not required to be additionally added, and the electromagnetic interference resistance is greatly improved; the whole structure is simple, the weight is light, the cost is low, and the installation, the calibration, the debugging and the maintenance are convenient.
When the electromagnetic signal measuring device is used, the end face of the current transformer accommodating groove sealing cover only needs to be attached to a measured power system, and after the measuring angle is adjusted, the electromagnetic signal can be measured when passing through the hollow inner cavity of the sensing coil, and the electromagnetic signal measuring device has the characteristics of high precision, good linearity and strong electromagnetic interference resistance.
[ description of the drawings ]
FIG. 1 is a schematic illustration of a main portion of an explosive structure according to a first embodiment of the present utility model;
FIG. 2 is a schematic view of a main portion of a three-dimensional structure according to a first embodiment of the present utility model;
FIG. 3 is a schematic cross-sectional view of a first embodiment of the present utility model;
FIG. 4 is a schematic view of a longitudinal cross-sectional structure of a first embodiment of the present utility model;
fig. 5 is a schematic diagram of the connection of two air coils in the first embodiment of the present utility model;
FIG. 6 is a schematic diagram of connection of four air coils in the second embodiment of the present utility model;
FIG. 7 is a schematic diagram of connection of four air coils in the second embodiment of the present utility model;
reference numerals:
l, a base; 2. a sensing coil; 3. a circular receiving groove; 4. a signal extraction channel; 5. and outputting a signal end.
[ detailed description ] of the utility model
The following description of the embodiments of the present utility model will be made clearly and completely with reference to the accompanying drawings, in which it is apparent that the embodiments described are only some embodiments of the present utility model, but not all embodiments. All other embodiments, which can be made by those skilled in the art based on the embodiments of the utility model without making any inventive effort, are intended to be within the scope of the utility model.
Example 1
The current transformer comprises a base l and 2 sensing coils 2, wherein the base l is a cylinder with an I-shaped structure, a circular accommodating groove 3 with an open top surface is formed in the top end of the cylinder, and a signal leading-out channel 4 which is convenient for leading out two output signal ends 5 of all the sensing coils 2 from the bottom end is formed in the axial center of the cylinder in a penetrating manner; each sensing coil 2 is made into a frame structure by hollow winding of an insulating wire, all the sensing coils 2 are respectively and symmetrically distributed around the hollow center, and after the two sensing coils 2 are connected in series and arranged in the same axis, the sensing coils are arranged in a containing groove of a base l and are sealed by an insulating adhesive (not shown in the figure); the two sensor coils 2 are arranged such that the superposition of induced electromotive forces induced in the two sensor coils 2 by a common electromagnetic field cancel each other out, leaving the two ends as output signal ends 5.
In this example, the two sensing coils 2 are made of the same insulated copper wire and uniformly and densely wound in a hollow center to form a multi-turn multi-layer flat square frame winding structure, and the shape, the size, the number of layers of the coils and the number of turns of each layer of the two sensing coils 2 are the same. Wherein the number of turns of the sensing coil 2 is 20-2000, preferably 50; the number of layers of the sensing coil 2 is preferably four; the diameter of the insulated copper wire in the sensor coil 2 is 0.05-1 mm, preferably 0.5mm.
Example two
As shown in fig. 6, the difference between the embodiment and the first embodiment is that four even sensing coils 2 are adopted, after two sensing coils 2 which are adjacent to each other and coaxially distributed are connected in series, the sensing coils are adjacent to each other and are parallelly distributed, and two groups of output ends are respectively connected in parallel and then are output and connected to the outside, so that the intensity of the induced current is effectively improved.
Example III
As shown in fig. 7, the difference between the embodiment and the first embodiment is that four even sensing coils 2 are adopted, after two sensing coils 2 which are adjacent to each other and coaxially distributed are connected in series, the two sensing coils are arranged in the same axial direction in an adjacent manner, and two groups of output ends are respectively connected in parallel and then are output and connected to the outside, so that the intensity of the induced current is also effectively improved.
In the above embodiment, since the current sensor with the air coil is adopted, no iron core is provided, the frequency bandwidth is provided, and the measurement can be performed no matter whether the electromagnetic induction signal is strong or weak; the even number of air coils are connected in series in a limiting mode, so that the superposition of induced electromotive forces caused by a common electromagnetic field in all the sensing coils is mutually offset, the interference of an external magnetic field is eliminated, and the electromagnetic interference resistance is greatly improved; the problem that current transformer needs symmetrical winding on the power system that is surveyed, be inconvenient for the measurement when measuring, when this embodiment uses, only need measure the terminal surface attached in the power system that is surveyed, after the adjustment measurement angle for electromagnetic signal can measure when passing from sensing coil cavity inner chamber, and is simple and convenient, effectively simplify the measurement degree of difficulty.
The above embodiments are merely preferred embodiments of the present utility model, and are not intended to limit the scope of the present utility model, but all equivalent changes according to the shape, construction and principle of the present utility model are intended to be included in the scope of the present utility model.
Claims (7)
1. A current transformer, comprising:
the top end of the base is provided with an accommodating groove;
the sensing coils are arranged in parallel after being connected in series or arranged in the same axis, are arranged in a containing groove of a base and are sealed by an insulating adhesive sealing cover;
all the sensing coils are configured so that the superposition of induced electromotive forces caused in all the sensing coils by a common electromagnetic field cancel each other out, and the two ends are reserved as output signal ends.
2. A current transformer according to claim 1, wherein: the sensing coils are all made of the same insulated wire, hollow centers of the sensing coils are uniformly and densely wound into a multi-turn single-layer or multi-layer frame winding structure, and the shape, the size, the number of layers of the coils and the number of turns of each layer of the sensing coils are the same.
3. A current transformer according to claim 1, wherein: the sensing coil is made of the same insulating copper wire through hollow winding, and is of a single-turn or multi-turn single-layer or multi-turn multi-layer frame winding structure.
4. A current transformer according to any one of claims 1 to 3, wherein: the sensing coil is of a flat square winding structure or a flat elliptic winding structure.
5. A current transformer according to any one of claims 1 to 3, wherein: the number of turns of the sensing coil is 20-2000.
6. A current transformer according to any one of claims 1 to 3, wherein: the insulated wire in the sensing coil is an insulated copper wire, and the diameter of the insulated copper wire is 0.05-1 mm.
7. A current transformer according to claim 1, wherein: the base is a cylinder with an I-shaped structure, a circular accommodating groove with an open top surface is formed in the top end of the cylinder, and a signal leading-out channel which is convenient for leading out two output signal ends of all the sensing coils from the bottom end is formed in the axial center of the cylinder in a penetrating way.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202321368900.2U CN219800651U (en) | 2023-05-31 | 2023-05-31 | Current transformer |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202321368900.2U CN219800651U (en) | 2023-05-31 | 2023-05-31 | Current transformer |
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| Publication Number | Publication Date |
|---|---|
| CN219800651U true CN219800651U (en) | 2023-10-03 |
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| CN202321368900.2U Active CN219800651U (en) | 2023-05-31 | 2023-05-31 | Current transformer |
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Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN118091222A (en) * | 2024-02-27 | 2024-05-28 | 苏州纬讯光电科技有限公司 | Magnetism gathering module and non-contact current sensor based on same |
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2023
- 2023-05-31 CN CN202321368900.2U patent/CN219800651U/en active Active
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN118091222A (en) * | 2024-02-27 | 2024-05-28 | 苏州纬讯光电科技有限公司 | Magnetism gathering module and non-contact current sensor based on same |
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