Combined type three-in-one current transformer

Abstract

The utility model relates to a combined type three-in-one current transformer which is characterized in that the combined type three-in-one current transformer comprises a first annular iron core, a second annular iron core, a third annular iron core, an A-phase coil, a B-phase coil, a C-phase coil and a shell, and the A-phase coil, the B-phase coil and the C-phase coil are wound on the first annular iron core, the second annular iron core and the third annular iron core respectively. Three mutual inductor units are formed, high-voltage insulating materials are filled between the shell and the mutual inductor units and between different mutual inductor units, and three through holes are formed in the shell; a first pair of wiring terminals, a second pair of wiring terminals and a third pair of wiring terminals are arranged on the outer surface of the shell; an insulating sleeve is arranged at the end of each through hole in the outer surface of the shell, and the end of each through hole is located in the corresponding sleeve. The combined type three-in-one current transformer has the advantages of being simple in structure, good in insulation performance, good in mechanical performance, small in size and convenient to maintain.

Description

Technical Field

[0001] This utility model relates to the field of power detection technology. More specifically, this utility model relates to a combined three-in-one current transformer. Background Technology

[0002] In power systems, to ensure the safe and stable operation of the power grid, it is typically necessary to measure the current flowing through power supply lines in real time. This allows for understanding the operating status and load of the power supply lines, calculating various line parameters, and determining whether abnormal conditions such as overload or short circuits have occurred. Based on the line's operating status, load, or abnormal conditions, the operating status of the power system can be adjusted. Furthermore, by monitoring and analyzing three-phase currents, the load distribution and power flow of the power grid can be understood, thereby adjusting the grid's operating status and achieving optimized grid operation. This helps improve the grid's transmission capacity and power supply reliability. In existing technologies, measuring the three-phase current of the power grid usually involves simultaneously acquiring three-phase current signals using three high-voltage transformers and measuring the acquired three-phase current signals using ammeters. However, the large size of three high-voltage transformers makes existing three-phase current measurement devices inconvenient to use. Utility Model Content

[0003] To address the technical problem of existing three-phase current measuring devices being too large and inconvenient to use, this utility model provides solutions in the following aspects.

[0004] In a first aspect, this utility model provides a combined three-in-one current transformer, comprising: a first toroidal core, a second toroidal core, a third toroidal core, an A-phase coil, a B-phase coil, a C-phase coil, and a housing. The A-phase coil, B-phase coil, and C-phase coil are respectively wound on the first toroidal core, the second toroidal core, and the third toroidal core to form three transformer units. The transformer units are placed inside the housing. High-voltage insulating material is filled between the housing and the transformer units, as well as between different transformer units. The housing has three through holes, which pass through the hollow parts of the three toroidal cores. A first pair of terminals, a second pair of terminals, and a third pair of terminals are provided on the outer surface of the housing. The first pair of terminals is connected to both ends of the A-phase coil, the second pair of terminals is connected to both ends of the B-phase coil, and the third pair of terminals is connected to both ends of the C-phase coil. An insulating sleeve is provided at the end of each through hole on the outer surface of the housing, with the end of the through hole located inside the corresponding sleeve.

[0005] Preferably, the sleeve is a circular sleeve.

[0006] Preferably, an A-phase sampling resistor is connected in series between the first pair of terminals, a B-phase sampling resistor is connected in series between the second pair of terminals, and a C-phase sampling resistor is connected in series between the third pair of terminals.

[0007] Preferably, the three perforations are axially parallel and arranged side by side, and the distance between adjacent perforations is equal.

[0008] Preferably, the three perforations are all elliptical in shape.

[0009] Preferably, high-voltage conductor outlets for conductors to pass through are provided on the high-voltage insulation material surrounding the A-phase coil, the B-phase coil, and the C-phase coil. Each high-voltage conductor outlet is connected to an insulation tower group. The two ends of the A-phase coil, the two ends of the B-phase coil, and the two ends of the C-phase coil pass through the corresponding insulation tower group and are connected to the corresponding terminals.

[0010] Preferably, each insulating tower group is equipped with an insulating tube, and the two ends of the A-phase coil, the two ends of the B-phase coil, and the two ends of the C-phase coil pass through the corresponding insulating tube and are connected to the corresponding terminals.

[0011] Preferably, the high-voltage insulating material is epoxy resin.

[0012] Preferably, the annular core is made of a single silicon steel strip.

[0013] The technical advantages of this invention are as follows: Most existing power systems require the simultaneous acquisition of three-phase current signals using three high-voltage transformers. However, the large size of these three transformers makes them inconvenient to use. This invention's combined three-in-one current transformer, employing a through-hole structure and integrating three transformer units into a single housing, significantly reduces the size of the three-phase current acquisition device. Furthermore, by filling the space between the housing and the transformer units, as well as between different transformer units, with high-voltage insulating material, and by providing insulating sleeves at the ends of each perforation on the outer surface of the housing, the creepage distance between the three phases and between the phase and ground is greatly improved, resulting in higher measurement accuracy and stability. This combined three-in-one current transformer can be used for the measurement and protection of three-phase current and zero-sequence current, and has the advantages of simple structure, good insulation performance, good mechanical properties, small size, convenient maintenance, and easy installation.

[0014] Furthermore, by setting a sampling resistor, the secondary open circuit of the current transformer can be avoided, thereby preventing potential fault hazards to power system equipment and personal safety.

[0015] Furthermore, since three conductive rods need to be passed through three holes when measuring three-phase current, and there may be quality issues with poor machining accuracy between the conductive rods and the holes, by setting the shape of the three holes to elliptical, the corresponding conductive rods can have a certain adjustment margin in the lateral direction, which makes it easier for the conductive rods and holes to fit together and be installed.

[0016] Furthermore, by connecting an insulated tower group at the high-voltage conductor outlet, mutual interference between different coils can be avoided, further increasing the creepage distance between the three phases.

[0017] Furthermore, by using epoxy resin as a high-voltage insulation material, moisture can be prevented, making the current transformer performance more stable and maintenance-free.

[0018] Furthermore, by using silicon steel strip to make the toroidal core, iron loss can be effectively reduced, and the efficiency and stability of the current transformer can be improved. Attached Figure Description

[0019] The above and other objects, features, and advantages of the present invention will become readily understood by reading the following detailed description of exemplary embodiments with reference to the accompanying drawings. In the drawings, several embodiments of the present invention are shown by way of example and not limitation, and like or corresponding reference numerals denote like or corresponding parts, wherein:

[0020] Figure 1 This is a top view of a combined three-in-one current transformer according to an embodiment of this utility model;

[0021] Figure 2 This is a cross-sectional view of a combined three-in-one current transformer according to an embodiment of this utility model. Detailed Implementation

[0022] The technical solutions of the present utility model will be clearly and completely described below with reference to the accompanying drawings of the embodiments. Obviously, the described embodiments are only some embodiments of the present utility model, not all embodiments. Based on the embodiments of the present utility model, all other embodiments obtained by those skilled in the art without creative effort are within the protection scope of the present utility model.

[0023] The specific embodiments of this utility model will now be described in detail with reference to the accompanying drawings.

[0024] Example of a combined three-in-one current transformer:

[0025] like Figure 1 and Figure 2As shown, the combined three-in-one current transformer of this utility model includes a first toroidal core, a second toroidal core, a third toroidal core, an A-phase coil, a B-phase coil, a C-phase coil, and a housing 1. The A-phase coil, B-phase coil, and C-phase coil are respectively wound on the first toroidal core, the second toroidal core, and the third toroidal core, forming three transformer units. The transformer units are placed inside the housing. High-voltage insulating material is filled between the housing and the transformer units, as well as between different transformer units. The housing has three through holes 2, which pass through the hollow parts of the three toroidal cores. A first pair of terminals, a second pair of terminals, and a third pair of terminals are provided on the outer surface of the housing. The first pair of terminals is connected to the two ends of the A-phase coil, the second pair of terminals is connected to the two ends of the B-phase coil, and the third pair of terminals is connected to the two ends of the C-phase coil. An insulating sleeve 3 is provided at the end of each through hole on the outer surface of the housing, with the end of the through hole located inside the corresponding sleeve. Figure 5 shows the terminals of the combined three-in-one current transformer of this utility model.

[0026] Three through holes are provided on the outer casing to allow the primary conductor to pass through the toroidal core, forming the primary winding. The A-phase coil, B-phase coil, and C-phase coil wound on the three cores form the secondary windings. When measuring the three-phase current, the three conductors carrying the three-phase current are passed through the three through holes respectively. The magnitude of the current through the primary conductor can be obtained by measuring the current in the secondary windings and combining this with the turns ratio of the primary and secondary windings.

[0027] Most existing power systems require the simultaneous acquisition of three-phase current signals using three high-voltage transformers. However, the large size of three high-voltage transformers makes them inconvenient to use. This embodiment of a combined three-in-one current transformer utilizes a through-hole structure, integrating three transformer units into a single housing, thus significantly reducing the size of the three-phase current acquisition device. Furthermore, by filling the space between the housing and the transformer units, as well as between different transformer units, with high-voltage insulating material, and by providing insulating sleeves at the ends of each perforation on the outer surface of the housing, the creepage distances between the three phases and between the phase and ground are greatly improved, resulting in higher measurement accuracy and stability. This combined three-in-one current transformer can be used for the measurement and protection of three-phase current and zero-sequence current, and has the advantages of simple structure, good insulation and mechanical properties, small size, convenient maintenance, and easy installation.

[0028] In one embodiment, the sleeve is a circular sleeve.

[0029] In one embodiment, a phase A sampling resistor is connected in series between the first pair of terminals, a phase B sampling resistor is connected in series between the second pair of terminals, and a phase C sampling resistor is connected in series between the third pair of terminals.

[0030] By setting a sampling resistor, the secondary open circuit of the current transformer can be avoided, thereby preventing potential fault hazards to power system equipment and personal safety.

[0031] In one embodiment, the three perforations are axially parallel and arranged side by side, and the distance between adjacent perforations is equal.

[0032] In one embodiment, the three perforations are all elliptical in shape.

[0033] When measuring three-phase current, three conductive rods need to be passed through three holes respectively, and there may be quality problems such as poor processing accuracy of the conductive rods and holes. By setting the shape of the three holes to elliptical, the corresponding conductive rods can have a certain adjustment margin in the lateral direction, which makes it easier for the conductive rods and holes to fit together and be installed.

[0034] In one embodiment, high-voltage conductor outlets 4 for conductors to pass through are provided on the high-voltage insulation material surrounding the A-phase coil, the B-phase coil, and the C-phase coil. Each high-voltage conductor outlet is connected to an insulation tower group. The two ends of the A-phase coil, the two ends of the B-phase coil, and the two ends of the C-phase coil pass through the corresponding insulation tower groups and are connected to the corresponding terminals.

[0035] By connecting a group of insulating towers at the outlet of the high-voltage conductor, mutual interference between different coils can be avoided, and the creepage distance between the three phases can be further increased.

[0036] In one embodiment, each insulating tower group is equipped with an insulating tube, and the two ends of the A-phase coil, the two ends of the B-phase coil, and the two ends of the C-phase coil pass through the corresponding insulating tube and are connected to the corresponding terminals.

[0037] In one embodiment, the high-voltage insulating material is epoxy resin.

[0038] Epoxy resin is a high molecular weight polymer with the molecular formula (C11H12O3)n, referring to a class of polymers containing two or more epoxy groups in their molecules. It is a condensation product of epichlorohydrin and bisphenol A or polyols. Epoxy resin possesses excellent electrical properties and mechanical strength, maintaining good performance under high temperature and high pressure environments. The presence of epoxy groups in its molecules, through curing and cross-linking to form a network structure, gives it thermosetting properties, further enhancing its insulating performance. Compared to other insulating materials, epoxy resin exhibits superior electrical properties and mechanical strength under high temperature and high pressure environments. Many insulating materials are prone to decomposition at high temperatures, and their electrical properties decrease with increasing temperature, making them unsuitable for high temperature and high pressure environments. Epoxy resin, on the other hand, has good chemical resistance and water resistance, especially performing better in humid environments.

[0039] The use of epoxy resin provides moisture protection, making the current transformer more stable and maintenance-free.

[0040] In one embodiment, the annular core is made from a single silicon steel strip.

[0041] Silicon steel strip, as an important soft magnetic alloy material, possesses a series of unique physical and chemical properties. Specifically, silicon steel strip has the following characteristics:

[0042] Excellent magnetic properties: Silicon steel strip has high permeability and low magnetic reluctance, enabling it to efficiently transfer magnetic field energy to the load. At the same time, its hysteresis loss and eddy current loss are relatively low, which helps reduce energy loss and heat generation in the equipment.

[0043] Excellent processing properties: Silicon steel strip is easy to cold roll, stamp, and cut, and can be made into parts of various shapes and sizes. In addition, it has good weldability and plasticity, making it easy to combine with other materials.

[0044] Low resistivity: Silicon steel strip has low resistivity, which means that it can generate less resistive heat under the same current, thereby extending the service life of the equipment.

[0045] High strength and toughness: Although silicon steel strip is relatively thin, it still has high strength and toughness and can withstand certain mechanical stress and vibration.

[0046] Corrosion resistance: The surface of silicon steel strips is typically treated with special methods to enhance their corrosion resistance. This helps prevent equipment from being damaged in humid or corrosive environments.

[0047] Temperature stability: The magnetic properties of silicon steel strip remain relatively stable within a certain temperature range, which allows it to work normally in high or low temperature environments.

[0048] Low noise and vibration: The high permeability and low hysteresis loss of silicon steel strips help reduce noise and vibration in equipment, thereby improving operating efficiency and comfort.

[0049] By using silicon steel strip to make the toroidal core, iron loss can be effectively reduced, and the efficiency and stability of the current transformer can be improved.

[0050] In the foregoing description of this specification, unless otherwise expressly specified and limited, the terms "connected" or "linked" should be interpreted broadly. For example, the term "linked" can refer to a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection or an indirect connection through an intermediate medium; or it can refer to the internal communication of two components or the interaction between two components. Therefore, unless otherwise expressly limited in this specification, those skilled in the art can understand the specific meaning of the above terms in this utility model based on the specific circumstances.

[0051] Furthermore, the terms "first" or "second," etc., used in this specification to refer to numbers or ordinal numbers are for descriptive purposes only and should not be construed as indicating, explicitly or implicitly, relative importance or specifying the number of indicated technical features. Therefore, a feature defined as "first" or "second" may explicitly or implicitly include at least one of that feature. In the description of this specification, "a plurality of" means at least two, such as two, three, or more, unless otherwise explicitly specified.

[0052] While this specification has shown and described various embodiments of the present invention, it will be apparent to those skilled in the art that such embodiments are provided by way of example only. Many modifications, alterations, and alternatives will occur to those skilled in the art without departing from the spirit and essence of the present invention. It should be understood that various alternatives to the embodiments of the present invention described herein may be employed in the practice of the present invention.

Claims

1. A combined three-in-one current transformer, characterized in that, include: The system comprises a first toroidal core, a second toroidal core, a third toroidal core, an A-phase coil, a B-phase coil, a C-phase coil, and a housing. The A-phase coil, B-phase coil, and C-phase coil are wound around the first, second, and third toroidal cores, respectively, forming three current transformer units. Each current transformer unit is housed inside the housing. High-voltage insulating material is filled between the housing and the current transformer units, as well as between different current transformer units. The housing has three through-holes, each passing through the hollow portion of one of the three toroidal cores. A first pair of terminals, a second pair of terminals, and a third pair of terminals are provided on the outer surface of the housing. The first pair of terminals connects to both ends of the A-phase coil, and the second pair of terminals connects to… The first pair of terminals is connected to the two ends of the B-phase coil, and the third pair of terminals is connected to the two ends of the C-phase coil. Insulating sleeves are provided at the ends of each perforation on the outer surface of the housing, with the ends of the perforations located inside the corresponding sleeves. A sampling resistor for phase A is connected in series between the first pair of terminals, a sampling resistor for phase B is connected in series between the second pair of terminals, and a sampling resistor for phase C is connected in series between the third pair of terminals. High-voltage conductor outlets are provided on the high-voltage insulation material surrounding the A-phase coil, the B-phase coil, and the C-phase coil. Each high-voltage conductor outlet is connected to an insulating tower group. The two ends of the A-phase coil, the two ends of the B-phase coil, and the two ends of the C-phase coil pass through the corresponding insulating tower groups and connect to the corresponding terminals.

2. The combined three-in-one current transformer as described in claim 1, characterized in that, The sleeve is a circular sleeve.

3. The combined three-in-one current transformer as described in claim 1, characterized in that, The three perforations are axially parallel and arranged side by side, and the distance between adjacent perforations is equal.

4. The combined three-in-one current transformer as described in claim 1, characterized in that, The three perforations are all elliptical in shape.

5. The combined three-in-one current transformer as described in claim 1, characterized in that, Each insulation tower group is equipped with an insulation tube. The two ends of the A-phase coil, the two ends of the B-phase coil, and the two ends of the C-phase coil pass through the corresponding insulation tube and are connected to the corresponding terminals.

6. The combined three-in-one current transformer as described in any one of claims 1 to 5, characterized in that, The high-voltage insulation material is epoxy resin.

7. The combined three-in-one current transformer as described in any one of claims 1 to 5, characterized in that, The annular core is made from a single silicon steel strip.

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