CN220933072U - Zero sequence current measurement circuit and three-phase integrated current transformer - Google Patents
Zero sequence current measurement circuit and three-phase integrated current transformer Download PDFInfo
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- CN220933072U CN220933072U CN202322212312.6U CN202322212312U CN220933072U CN 220933072 U CN220933072 U CN 220933072U CN 202322212312 U CN202322212312 U CN 202322212312U CN 220933072 U CN220933072 U CN 220933072U
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- 238000005259 measurement Methods 0.000 title claims abstract description 37
- 238000000819 phase cycle Methods 0.000 claims abstract description 102
- 238000004804 winding Methods 0.000 claims abstract description 72
- 238000001514 detection method Methods 0.000 claims abstract description 56
- XEEYBQQBJWHFJM-UHFFFAOYSA-N Iron Chemical group [Fe] XEEYBQQBJWHFJM-UHFFFAOYSA-N 0.000 claims description 27
- 230000009466 transformation Effects 0.000 description 6
- 230000035945 sensitivity Effects 0.000 description 3
- 230000009286 beneficial effect Effects 0.000 description 2
- 230000004907 flux Effects 0.000 description 2
- 238000009434 installation Methods 0.000 description 2
- 229910000976 Electrical steel Inorganic materials 0.000 description 1
- 206010063385 Intellectualisation Diseases 0.000 description 1
- 239000002131 composite material Substances 0.000 description 1
- 238000010276 construction Methods 0.000 description 1
- 238000010586 diagram Methods 0.000 description 1
- 230000005674 electromagnetic induction Effects 0.000 description 1
- 230000006698 induction Effects 0.000 description 1
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Abstract
The utility model relates to the technical field of current transformers, and discloses a zero sequence current measurement circuit and a three-phase integrated current transformer. The phase sequence detection unit comprises a phase sequence first coil and a phase sequence second coil; the current detection unit comprises an A-phase secondary current detection loop, a B-phase secondary current detection loop and a C-phase secondary current detection loop; the zero sequence detection unit comprises a zero sequence coil which is connected with the phase sequence detection unit in a matched mode, the zero sequence coil comprises a zero sequence first winding, and two ends of a phase sequence second winding b are respectively connected with two ends of the zero sequence first winding to form a zero sequence current secondary detection loop. The utility model can rapidly detect the working current of the clock battery power supply loop under the condition of not opening the shell of the intelligent electric energy meter, and effectively troubleshoot the power supply loop. The utility model can solve the problems of insufficient space for installing the current transformer of the miniaturized intelligent switch equipment and low zero sequence current measurement precision.
Description
Technical Field
The utility model relates to the technical field of current transformers, in particular to a zero sequence current measurement circuit and a three-phase integrated current transformer.
Background
In order to meet the requirements of smart grid construction, a switching device for a smart grid needs to be provided with three-phase integrated current transformers, and a large part of the three-phase integrated current transformers also need to be provided with zero sequence current transformers. The requirement of intellectualization and miniaturization of the switch device now, therefore, the requirement of realizing accurate measurement of current in a limited installation space becomes a starting point for solving the problem in the switch industry.
The main current solution is to integrate A, B, C three-phase current transformers and a zero sequence current transformer into a three-phase integrated current transformer with a zero sequence measurement function. The traditional zero sequence current transformer adopts a runway type iron core structure, three-phase current is synthesized into zero sequence current at the primary side, but because the distance between a A, B, C three-phase circuit and an iron core is unevenly distributed, the magnetic density of the runway type iron core is unevenly distributed, so that the induced zero sequence secondary current has large measurement error, poor sensitivity and the like, and the current transformer of the structure is restricted by factors such as low measurement precision, large volume, large weight, inconvenient installation and the like, and is easy to cause the problems of protection and movement rejection and the like, thereby affecting the reliability and stability of switch equipment and being difficult to meet the requirements of a power system.
Disclosure of utility model
This section is intended to outline some aspects of embodiments of the utility model and to briefly introduce some preferred embodiments. Some simplifications or omissions may be made in this section as well as in the description of the utility model and in the title of the utility model, which may not be used to limit the scope of the utility model.
The utility model is provided in view of the problem that the magnetic density of a runway type iron core is unevenly distributed due to uneven distance distribution between a three-phase circuit and the iron core of the traditional zero sequence current transformer, and the induced zero sequence secondary current has large measurement error.
In order to solve the technical problems, the utility model provides the following technical scheme: the zero sequence current measurement circuit comprises a phase sequence detection unit, wherein the phase sequence detection unit comprises a phase sequence first coil and a phase sequence second coil, and A/B/C three phases of the phase sequence first coil and the phase sequence second coil respectively correspond to A, B, C three-phase circuits to be measured;
The current detection unit comprises an A-phase secondary current detection loop, a B-phase secondary current detection loop and a C-phase secondary current detection loop, wherein the A/B/C three phases of the phase sequence first winding of the phase sequence first coil are respectively connected with the A-phase secondary current detection loop, the B-phase secondary current detection loop and the C-phase secondary current detection loop; the zero sequence detection unit comprises a zero sequence coil which is connected with the phase sequence detection unit in a matched mode, the zero sequence coil comprises a zero sequence first winding, two ends of the zero sequence first winding are respectively connected with two ends of a phase sequence second winding to form a zero sequence current secondary detection loop, and one end of the zero sequence first winding is grounded.
As a preferred embodiment of the zero sequence current measurement circuit according to the utility model, the zero sequence current measurement circuit comprises: the phase sequence first coil further comprises a phase sequence first iron core, and the A/B/C three phases of the phase sequence first iron core respectively correspond to A, B, C three-phase circuits to be tested.
As a preferred embodiment of the zero sequence current measurement circuit according to the utility model, the zero sequence current measurement circuit comprises: the phase sequence second coil further comprises a phase sequence second iron core, and the phase sequence first iron core and the phase sequence second iron core share a phase sequence first winding.
As a preferred embodiment of the zero sequence current measurement circuit according to the utility model, the zero sequence current measurement circuit comprises: the zero-sequence coil further comprises a zero-sequence iron core and a zero-sequence second winding, and the zero-sequence first winding and the zero-sequence second winding share the zero-sequence iron core.
As a preferred embodiment of the zero sequence current measurement circuit according to the utility model, the zero sequence current measurement circuit comprises: and the access polarity of the phase sequence second coil is consistent.
As a preferred embodiment of the zero sequence current measurement circuit according to the utility model, the zero sequence current measurement circuit comprises: the winding directions of the phase sequence first windings are identical, the winding directions of the phase sequence second windings are identical, and the winding numbers of the phase sequence second windings are identical.
The utility model has the beneficial effects that: the secondary current potential induced by the A/B/C three phases of the phase sequence second coil is synthesized into zero sequence current, and the phase sequence windings of the three-phase sequence coil are tightly wound, so that the problem of nonuniform magnetic field is solved, and the measurement requirements of high precision and high sensitivity of the phase sequence current and the zero sequence current are met.
The utility model further aims to provide a three-phase integrated current transformer, which aims to solve the problems that the internal layout of the existing current transformer is unreasonable and the occupied volume is overlarge.
As a preferable scheme of the three-phase integrated current transformer, the utility model comprises the following steps: the zero sequence current measuring circuit comprises the zero sequence current measuring circuit and further comprises a shell, wherein the shell comprises a first mounting hole, a second mounting hole and a third mounting hole, and the A/B/C three phases of the phase sequence first coil and the phase sequence second coil are respectively sleeved in the first mounting hole, the second mounting hole and the third mounting hole.
As a preferable scheme of the three-phase integrated current transformer, the utility model comprises the following steps: the zero sequence coil is arranged in the middle layer of the shell, and the zero sequence second winding is connected with a zero sequence current secondary detection loop through a terminal on the shell.
As a preferable scheme of the three-phase integrated current transformer, the utility model comprises the following steps: the A/B/C three-phase equal distance of the phase sequence first coil is arranged on one side of the middle layer of the shell, and the phase sequence first winding is respectively connected with the A-phase secondary current detection loop, the B-phase secondary current detection loop and the C-phase secondary current detection loop through connecting terminals on the shell.
As a preferable scheme of the three-phase integrated current transformer, the utility model comprises the following steps: the A/B/C three phases of the phase sequence second coil are equidistantly arranged on the other side of the middle layer of the shell.
The utility model has the beneficial effects that: the three-phase integrated current transformer with the zero sequence current measurement function can be installed in a small space of the miniaturized intelligent switch equipment, and the current transformer is high in precision and sensitivity.
Drawings
In order to more clearly illustrate the technical solutions of the embodiments of the present utility model, the drawings that are needed in the description of the embodiments will be briefly described below, it being obvious that the drawings in the following description are only some embodiments of the present utility model, and that other drawings may be obtained according to these drawings without inventive effort for a person skilled in the art. Wherein:
FIG. 1 is an electrical schematic diagram of a zero sequence current measurement circuit and a three-phase integrated current transformer of the present utility model;
FIG. 2 is a bottom cutaway view of the zero sequence current measurement circuit and three-phase integrated current transformer of the present utility model;
FIG. 3 is a cross-sectional view of an intermediate layer of the zero sequence current measurement circuit and three-phase integrated current transformer of the present utility model;
FIG. 4 is a cross-sectional view of the zero sequence current measurement circuit and three-phase integrated current transformer of the present utility model;
Fig. 5 is a half-sectional view of the zero sequence current measurement circuit and the three-phase integrated current transformer of the present utility model.
Detailed Description
In order that the above-recited objects, features and advantages of the present utility model will become more readily apparent, a more particular description of the utility model will be rendered by reference to specific embodiments thereof which are illustrated in the appended drawings.
In the following description, numerous specific details are set forth in order to provide a thorough understanding of the present utility model, but the present utility model may be practiced in other ways other than those described herein, and persons skilled in the art will readily appreciate that the present utility model is not limited to the specific embodiments disclosed below.
Further, reference herein to "one embodiment" or "an embodiment" means that a particular feature, structure, or characteristic can be included in at least one implementation of the utility model. The appearances of the phrase "in one embodiment" in various places in the specification are not necessarily all referring to the same embodiment, nor are separate or alternative embodiments mutually exclusive of other embodiments.
Example 1
Referring to fig. 1, a first embodiment of the present utility model provides a zero sequence current measurement circuit, which includes a phase sequence detection unit 100 including a phase sequence first coil 101 and a phase sequence second coil 102, wherein a/B/C three phases of the phase sequence first coil 101 and the phase sequence second coil 102 respectively correspond to A, B, C three-phase lines to be measured; the current detection unit 200 comprises an A-phase secondary current detection loop 201, a B-phase secondary current detection loop 202 and a C-phase secondary current detection loop 203, wherein the A/B/C three phases of the phase sequence first winding 101B of the phase sequence first coil 101 are respectively connected with the A-phase secondary current detection loop 201, the B-phase secondary current detection loop 202 and the C-phase secondary current detection loop 203; the zero sequence detection unit 300 comprises a zero sequence coil 301 which is cooperatively connected with the phase sequence detection unit 100, the zero sequence coil 301 comprises a zero sequence first winding 301b, two ends of a phase sequence second winding 102b are respectively connected with two ends of the zero sequence first winding 301b to form a zero sequence current secondary detection loop 304, and one end of the zero sequence first winding 301b is grounded.
The phase-sequence first coil 101 further comprises a phase-sequence first iron core 101a, and the A/B/C three phases of the phase-sequence first iron core 101a respectively correspond to A, B, C three-phase circuits to be tested.
The phase-sequence second coil 102 further includes a phase-sequence second core 102a, and the phase-sequence first core 101a and the phase-sequence second core 102a share the phase-sequence first winding 101b.
The zero sequence coil 301 further comprises a zero sequence core 301a and a zero sequence second winding 301c, the zero sequence first winding 301b and the zero sequence second winding 301c sharing the zero sequence core 301a.
The phase sequence second coil 102 is connected in polarity. The phase sequence first windings 101b are wound in the same direction, and the number of turns is the same, and the phase sequence second windings 102 are wound in the same direction.
The winding is wound in a double-strand lap winding or single-strand lap winding mode respectively, and the iron core is made of a single structure or a composite structure of high-permeability iron-based nanocrystalline and low-iron-loss silicon steel sheet materials.
According to the electromagnetic induction principle, the primary currents of A, B, C three-phase lines are respectively converted into corresponding secondary currents through the A/B/C three phases of the phase sequence second coil 102, the three-phase secondary currents are synthesized into zero-sequence currents in the zero-sequence first winding 301B of the zero-sequence coil 301, the zero-sequence currents are excited in the zero-sequence iron core 301a and are superposed to generate zero-sequence magnetic fluxes, and therefore the zero-sequence secondary currents are induced in the zero-sequence second winding 301C.
Further, by synthesizing the secondary current potential induced by the phase sequence second coil 102 into zero sequence current, the phase sequence windings of the three-phase sequence coil are tightly wound, so that the problem of nonuniform magnetic field is solved. When the zero-sequence current of A, B, C three-phase line is zero, the vector sum of the synthesized zero-sequence currents in the zero-sequence first winding 301b of the zero-sequence coil 301 is zero, so that the zero-sequence secondary current induced in the zero-sequence second winding 301c is zero. When the zero-sequence current of the A, B, C three-phase line is not zero, the zero-sequence current synthesized by the secondary currents induced by the A, B, C three-phase sequence second coil 102 is not zero, and magnetic flux is generated in the zero-sequence iron core 301a and is not zero, so that the zero-sequence secondary current in proportional relation with the zero-sequence current of the three-phase line is induced in the zero-sequence second winding 301 c.
Example 2
Referring to fig. 1, in a second embodiment of the present utility model, further, the phase sequence coil has a through-core structure, the number of turns of the phase sequence winding is determined to be N1 according to the transformation ratio of the current transformer, and it is ensured that the number of turns of the phase sequence first coil 101 and the number of turns of the phase sequence second coil 102 are the same, the winding directions are consistent, and at this time, the phase sequence windings of the a/B/C three phases of the phase sequence first coil 101 are respectively connected to A, B, C three-phase current secondary detection loops for outputting three-phase secondary induction currents.
The phase sequence windings of the a/B/C three phases of the phase sequence second coil 102 are respectively connected to the zero sequence first winding 301B of the zero sequence coil 301, and the induced zero sequence secondary current is connected to the zero sequence current secondary detection loop 304 through the zero sequence second winding 301C. Wherein the number of turns of the zero-sequence first winding of the zero-sequence coil is N2, and the number of turns of the zero-sequence second winding is N3. The total transformation ratio relationship of the zero sequence current is K/1=n1×n3/N2.
Example 3
Referring to fig. 2 to 5, a third embodiment of the present utility model is different from the first two embodiments in that: the motor further comprises a shell 400, wherein the shell comprises a first mounting hole 401, a second mounting hole 402 and a third mounting hole 403, and the A/B/C three phases of the phase sequence first coil 101 and the phase sequence second coil 102 are respectively sleeved in the first mounting hole 401, the second mounting hole 402 and the third mounting hole 403.
All coils are arranged in the shell, the shell is horizontally arranged, and the coils are sequentially distributed from bottom to top.
The zero sequence coil 301 is arranged in the middle layer of the shell 400, and the zero sequence second winding 301c is connected with the zero sequence current secondary detection loop 304 through a connecting terminal on the shell 400.
The a/B/C three phases of the phase sequence first coil 101 are arranged at one side of the middle layer of the shell 400 at equal distances, and the phase sequence first winding 101B is respectively connected with the a-phase secondary current detection circuit 201, the B-phase secondary current detection circuit 202 and the C-phase secondary current detection circuit 203 through connecting terminals on the shell 400.
The a/B/C three phases of the phase sequence second coil 102 are equidistantly disposed on the other side of the intermediate layer of the housing 400.
The transformation ratio requirement of the three-phase integrated current transformer is as follows: the transformation ratio of the phase sequence current transformer is 600A/1A; the transformation ratio of the zero sequence current transformer is 100A/1A.
The number of turns of each coil winding is designed according to the turn ratio relation of the current transformer, the number of turns N1 of the phase sequence winding is 600 turns, and the turn ratio N2/N3=1/6 of the zero sequence first winding 301b and the zero sequence second winding 301c of the zero sequence coil 301 is calculated according to the total transformation ratio relation K/1=N1×N3/N2=600×N3/N2=100/1 of the zero sequence current. And then the number of turns is respectively 20 turns and 120 turns according to the iron core size design of the zero sequence coil 301, the requirements of measurement precision, carrying capacity and the like.
It should be noted that the above embodiments are only for illustrating the technical solution of the present utility model and not for limiting the same, and although the present utility model has been described in detail with reference to the preferred embodiments, it should be understood by those skilled in the art that the technical solution of the present utility model may be modified or substituted without departing from the spirit and scope of the technical solution of the present utility model, which is intended to be covered in the scope of the claims of the present utility model.
Claims (10)
1. A zero sequence current measurement circuit, characterized in that: comprising the steps of (a) a step of,
The phase sequence detection unit (100) comprises a phase sequence first coil (101) and a phase sequence second coil (102), wherein the A/B/C three phases of the phase sequence first coil (101) and the phase sequence second coil (102) respectively correspond to A, B, C three-phase circuits to be detected;
the current detection unit (200) comprises an A-phase secondary current detection circuit (201), a B-phase secondary current detection circuit (202) and a C-phase secondary current detection circuit (203), wherein the A/B/C three phases of a phase sequence first winding (101B) of the phase sequence first coil (101) are respectively connected with the A-phase secondary current detection circuit (201), the B-phase secondary current detection circuit (202) and the C-phase secondary current detection circuit (203);
the zero sequence detection unit (300) comprises a zero sequence coil (301) which is connected with the phase sequence detection unit (100) in a matching way, the zero sequence coil (301) comprises a zero sequence first winding (301 b), two ends of the zero sequence first winding (301 b) are respectively connected with two ends of a phase sequence second winding (102 b) to form a zero sequence current secondary detection loop (304), and one end of the zero sequence first winding (301 b) is grounded.
2. The zero sequence current measurement circuit of claim 1, wherein: the phase sequence first coil (101) further comprises a phase sequence first iron core (101 a), and the A/B/C three phases of the phase sequence first iron core (101 a) respectively correspond to A, B, C three-phase circuits to be tested.
3. The zero sequence current measurement circuit of claim 2, wherein: the phase sequence second coil (102) further comprises a phase sequence second iron core (102 a), and the phase sequence first iron core (101 a) and the phase sequence second iron core (102 a) share a phase sequence first winding (101 b).
4. A zero sequence current measurement circuit according to claim 2 or 3, characterized in that: the zero sequence coil (301) further comprises a zero sequence iron core (301 a) and a zero sequence second winding (301 c), and the zero sequence first winding (301 b) and the zero sequence second winding (301 c) share the zero sequence iron core (301 a).
5. The zero sequence current measurement circuit of claim 4, wherein: the phase sequence second coil (102) is connected with the same polarity.
6. The zero sequence current measurement circuit of claim 5, wherein: the winding directions of the phase sequence first windings (101 b) are consistent, the winding numbers of the phase sequence second windings (102) are the same, and the winding directions of the phase sequence second windings are the same.
7. A three-phase integrated current transformer is characterized in that: comprising a zero sequence current measurement circuit according to any one of claims 2, 3, 5 to 6, further comprising,
The shell (400) comprises a first mounting hole (401), a second mounting hole (402) and a third mounting hole (403), wherein the A/B/C three phases of the phase sequence first coil (101) and the phase sequence second coil (102) are respectively sleeved in the first mounting hole (401), the second mounting hole (402) and the third mounting hole (403).
8. The three-phase integrated current transformer of claim 7, wherein: the zero sequence coil (301) is arranged in the middle layer of the shell (400), and the zero sequence second winding (301 c) is connected with the zero sequence current secondary detection loop (304) through a terminal on the shell (400).
9. The three-phase integrated current transformer of claim 8, wherein: the A/B/C three-phase equal distance of the phase sequence first coil (101) is arranged on one side of the middle layer of the shell (400), and the phase sequence first winding (101B) is respectively connected with the A-phase secondary current detection loop (201), the B-phase secondary current detection loop (202) and the C-phase secondary current detection loop (203) through connecting terminals on the shell (400).
10. The three-phase integrated current transformer according to claim 8 or 9, wherein: the A/B/C three phases of the phase sequence second coil (102) are equidistantly arranged on the other side of the middle layer of the shell (400).
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202322212312.6U CN220933072U (en) | 2023-08-17 | 2023-08-17 | Zero sequence current measurement circuit and three-phase integrated current transformer |
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| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202322212312.6U CN220933072U (en) | 2023-08-17 | 2023-08-17 | Zero sequence current measurement circuit and three-phase integrated current transformer |
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| CN220933072U true CN220933072U (en) | 2024-05-10 |
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| CN202322212312.6U Active CN220933072U (en) | 2023-08-17 | 2023-08-17 | Zero sequence current measurement circuit and three-phase integrated current transformer |
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| CN (1) | CN220933072U (en) |
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2023
- 2023-08-17 CN CN202322212312.6U patent/CN220933072U/en active Active
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