Current transformer and switchgear comprising same

Abstract

The invention relates to a current transformer and switch equipment comprising the same, the current transformer comprises a current transformer main body (1) formed by casting, a current conversion assembly (2) embedded in the current transformer main body and a primary conductor (3), and the primary conductor (3) comprises a first end (31) and a second end (32). Wherein any one of the first end and the second end is used as a wire inlet terminal of the current transformer, the other one is used as a wire outlet terminal of the current transformer, and the first end is further constructed as a static contact of the current transformer. As the terminal of the current transformer is used as the static contact, an independent conductor and a static contact which are connected with the current transformer and the static contact in the prior art are omitted, the number of parts is reduced, and the cost is reduced. The current transformer is further integrated with a temperature measuring device, so that the temperature of the moving contact in contact with the static contact and the temperature of the electrical component where the moving contact is located can be measured more accurately, and the temperature of an external component such as a bus side cable or a copper bar can be monitored.

Description

Technical Field

[0001] This invention relates to the technical field of current transformers, and more particularly to a current transformer for use in switchgear (also known as switch cabinets). Background Technology

[0002] In power generation, transformation, transmission, distribution, and consumption lines, the current varies greatly, ranging from a few amperes to tens of thousands of amperes. To facilitate measurement, protection, and control, it is necessary to convert the current to a more uniform value. Furthermore, the voltage on these lines is generally quite high, making direct measurement extremely dangerous. Current transformers serve to transform current and provide electrical isolation. They are instruments that convert large primary currents into smaller secondary currents (e.g., standard small currents of 1A or 5A) based on the principle of electromagnetic induction. Current transformers also isolate high-voltage, high-current systems to ensure the safety of personnel and equipment.

[0003] Existing current transformers, such as in Figure 8 and Figures 9A-9C A current transformer is shown. The current transformer 100 shown is installed in a switching device, which is partially shown. The upper conductive terminal of the current transformer 100 is connected to a stationary contact 101a (see [reference needed]) via a first conductor 101 (which may be a copper busbar). Figure 9C The stationary contact 101a is electrically connected to the moving contact (not shown) of the circuit breaker in the operating position. The lower conductive terminal of the current transformer 100 is electrically connected to the second conductor 102, thereby achieving an electrical connection.

[0004] Such existing current transformers require connection to the moving contacts of, for example, circuit breakers via a first conductor 101 with a stationary contact 101a. This results in numerous components, a complex structure, and a large and heavy contact box 104 (see [link to relevant documentation]). Figure 9B This achieves insulation protection for the stationary contact. Furthermore, since the high-voltage first conductor 101 is exposed, a separate insulating isolator 103 is required for it (see...). Figure 9A ).

[0005] In high-current circuits, various connection points, i.e., the joints of electrical components, generate significant heat. If the temperature of these key heat-generating areas is not monitored, heat accumulation can easily lead to damage to electrical components and safety hazards. However, existing current transformers only focus on functions such as measurement, protection, current standardization, and / or safety isolation, and do not have temperature monitoring capabilities. Summary of the Invention

[0006] The purpose of this invention is to solve at least one of the above-mentioned problems and / or other problems existing in the prior art.

[0007] To achieve the above objectives, according to one aspect of the present invention, a current transformer is provided, the current transformer comprising a cast current transformer body, a current conversion assembly including a primary winding and a secondary winding embedded in the current transformer body, and a primary conductor supplying power to the primary winding, the primary conductor including a first end and a second end, wherein either the first end or the second end serves as an input terminal of the current transformer and the other serves as an output terminal of the current transformer, and the first end is further configured as a stationary contact of the current transformer.

[0008] In this solution, by directly constructing the first end of the primary conductor of the current transformer, which serves as either the input or output terminal, as the stationary contact of the current transformer, the additional conductor connecting the current transformer terminals and the stationary contact, as in existing technologies, is eliminated. This minimizes the number of components, reduces costs, and makes the switchgear structure more compact, occupying less space and facilitating miniaturization. Furthermore, since the absence of an exposed additional conductor connecting the current transformer terminals and the stationary contact enhances the safety performance of the switchgear. Moreover, the stationary contact is directly integrated with the primary conductor, eliminating the need for mounting or connecting parts, thus simplifying the current transformer structure and improving its electrical performance.

[0009] According to one embodiment of the invention, the current transformer further includes a temperature measuring device comprising a first temperature-sensing component that contacts the stationary contact. Since this first temperature-sensing component directly contacts the stationary contact, it can directly measure the temperature of the stationary contact and the moving contact it contacts (the temperature of the moving contact is directly conducted to the stationary contact), thus allowing for more accurate measurement of the temperature of the electrical component where the moving contact is located. This is particularly advantageous when the stationary contact is connected to the moving contact of a circuit breaker, enabling monitoring of the circuit breaker temperature.

[0010] According to one embodiment of the invention, the temperature measuring device further includes an electrical connection port exposed on the outer surface of the current transformer body, enabling the temperature measuring device to acquire the measured temperature of external components of the current transformer. Thus, the current transformer has two temperature monitoring points, which can monitor not only the temperature inside the current sensor and the connected circuit breaker in real time, but also the temperature of external components such as busbar-side components (e.g., cables or copper busbars).

[0011] According to one embodiment of the invention, the primary conductor includes a tubular portion, wherein the first end is the free end of the tubular portion, and the first temperature measuring component is disposed on the inner wall of the free end of the tubular portion. This facilitates the arrangement and positioning of the temperature measuring device and facilitates the casting process.

[0012] According to one embodiment of the invention, the primary conductor further includes an extension, one end of which is connected to the tubular portion, and the other end of which constitutes a second end of the primary conductor, wherein the second end is configured as a plate. This plate-shaped second end, serving as an input or output terminal, allows for a larger area and easier electrical connection to an external conductor.

[0013] According to one embodiment of the invention, the temperature measuring device further includes a wire connected to the electrical connection port, the wire extending along the tubular portion and the extension portion. This arrangement facilitates the positioning of the wire during the casting process of the current transformer body.

[0014] According to one embodiment of the invention, the current conversion assembly further includes an additional secondary winding that supplies power to the temperature measuring device. This configuration realizes an active temperature measuring device integrated into a current transformer.

[0015] According to one embodiment of the invention, the current transformer includes a cylindrical portion extending beyond the stationary contact and integrally formed with the current transformer body. This cylindrical portion is integrally cast with the current transformer body using an insulating material, surrounding the stationary contact and insulating it (which is also the connection point between the moving and stationary contacts). Therefore, a separate insulating isolator for the stationary contact is unnecessary, and the size of the contact box can be reduced, or even replaced entirely. This saves material and internal space of the switching device, facilitating miniaturization of the switching device and providing better insulation performance.

[0016] According to one embodiment of the invention, the stationary contact is configured to make contact with the moving contact of the circuit breaker of the switching equipment for electrical connection.

[0017] According to one embodiment of the invention, the current transformer further includes a power-taking component, one end of which is electrically connected to the primary conductor, and the other end of which is adapted to be electrically connected to an indicating device for indicating the energized or de-energized state of the current transformer. "Electrically connected" as used herein can refer to direct contact and electrical connection, or electrical connection via one or more intermediate conductive components. This approach integrates the power-taking component into the current transformer, avoiding the need for an additional power-taking component in the switching equipment. Furthermore, since the power-taking component is embedded within the insulating body of the current transformer, no additional insulating support is required for the power-taking component, thus reducing the overall number of electrical components and lowering the complexity of the switching equipment.

[0018] According to another aspect of the invention, a switching device is also provided, which includes a current transformer as described in the foregoing examples. According to one example, the electrical connection port of the temperature measuring device of the current transformer in the switching device is electrically connected to a second temperature measuring component disposed on a cable or copper busbar on the bus side of the switching device. Attached Figure Description

[0019] The features and advantages of the present invention will become clear from the following detailed description provided with reference to the accompanying drawings. It should be understood that the following drawings are merely schematic and not necessarily drawn to scale, and therefore should not be considered as limitations on the invention, wherein:

[0020] Figure 1 A perspective view of an exemplary current transformer according to the present invention is shown.

[0021] Figure 2 Show Figure 1 A three-dimensional schematic diagram of the current transformer from another angle.

[0022] Figure 3 Show Figure 1 The diagram shows a three-dimensional cross-sectional view of the current transformer along line AA.

[0023] Figure 4 A three-dimensional schematic diagram of some electrical components embedded in the body of a current transformer is shown, wherein the cast current transformer body is not shown.

[0024] Figure 5 Another perspective view shows some of the electrical components embedded in the body of the current transformer.

[0025] Figure 6 Show Figure 5 A cross-sectional view of the electrical component along line BB.

[0026] Figure 7 A schematic diagram of a switching device equipped with a current transformer according to an exemplary embodiment of the present invention is shown.

[0027] Figure 8 A schematic diagram of an existing current transformer installed in a switchgear is shown.

[0028] Figure 9A Show Figure 8 A three-dimensional schematic diagram of the insulating isolation component.

[0029] Figure 9B Show Figure 8 A three-dimensional schematic diagram of the contact box in the diagram.

[0030] Figure 9C Show Figure 8 A schematic diagram of the first conductor in the diagram. Detailed Implementation

[0031] Specific embodiments of the present invention are described below with reference to the accompanying drawings. In the following description, numerous specific details are set forth to enable those skilled in the art to more fully understand and implement the invention. However, it will be apparent to those skilled in the art that implementations of the invention may not include some of these specific details. Furthermore, it should be understood that the invention is not limited to the specific embodiments described. Rather, the invention can be conceived to be practiced with any combination of the features and elements described below, regardless of whether they relate to different embodiments.

[0032] Figure 7 A schematic diagram of a switchgear (also called a switch cabinet) with a current transformer 10 installed according to an exemplary embodiment of the present invention is shown, in which the current transformer 10 is schematically shown in a portion with cross-section (the circuit breaker is not shown in the figure for simplicity). Figure 1 and Figure 2 A perspective view of the current transformer 10 of this specific embodiment is shown. Figure 3 It shows along Figure 1 A three-dimensional cross-sectional view of the AA line. The main body 1 of the current transformer can be cast from an insulating material such as epoxy resin, and various electrical components, including the current conversion assembly 2, are embedded within it. The current conversion assembly 2 is... Figure 3 as well as Figure 4 The diagram is schematically shown as a block, specifically comprising a primary winding and a secondary winding for converting a large current on the primary side into a current on the secondary side (e.g., a current suitable for measuring instruments). The current conversion component 2, being prior art, will not be described in detail herein. Figure 3 As shown, the primary conductor 3 supplying power to the primary winding of the current conversion component 2 includes a first end 31 and a second end 32. In this embodiment of the invention, one of the first end 31 or the second end 32 serves as the input terminal of the current transformer, and correspondingly the other serves as the output terminal of the current transformer. The first end 31 is configured as the stationary contact of the current transformer. The converted secondary current flows through... Figure 2 The secondary output terminal 35 shown in the figure is led out.

[0033] In the present invention, by directly constructing the first end of the primary conductor 3, which serves as either an input or output terminal, as the stationary contact of the current transformer, the separate conductor connected to the current transformer and the stationary contact (e.g., the stationary contact) in the prior art are omitted. Figure 8 and Figure 9CThe first conductor 101 and the stationary contact 101a are integrated directly with the primary conductor, which reduces the number of parts to a minimum, lowers costs and simplifies assembly, and makes the switchgear structure more compact, occupies less space, and is easier to miniaturize.

[0034] like Figure 1-3 As shown, the current transformer includes a cylindrical portion 11 that extends beyond the stationary contact (i.e., the first end of the primary conductor 3) and is integrally formed with the current transformer body 1. This cylindrical portion 11 is integrally cast with the current transformer body 1 using insulating material, and surrounds the stationary contact to insulate it (which is also the connection point between the moving contact and the stationary contact). Therefore, a separate insulating isolator (e.g., an additional insulating layer) is not required. Figure 8 and attached Figure 9A The insulating isolator 103 in the middle can reduce the size of the contact box and can even replace the separate contact box (e.g., with an additional insulating isolator). Figure 8 and attached Figure 9B (Contact box 104 in the middle).

[0035] The current transformer in this embodiment saves costs, saves space, and facilitates the miniaturization of switching equipment by reducing the use of conductors and insulating components and reducing or eliminating the need for contact boxes.

[0036] In this embodiment, a temperature measuring device 4 is also provided for the current transformer. A significant feature of the temperature measuring device in this invention is that it includes a first temperature-sensing component that contacts the stationary contact. This temperature-sensing component, acting as a data collection and conversion unit, can acquire the temperature information of the measured component. In other words, the first temperature-sensing component of the temperature measuring device directly contacts the stationary contact, thus enabling direct measurement of the temperature of the stationary contact and the moving contact it contacts (the temperature of the moving contact is directly conducted to the stationary contact). Therefore, the temperature of the electrical component where the moving contact is located can be measured more accurately. This is particularly advantageous when the stationary contact is connected to the moving contact of the circuit breaker, enabling monitoring of the circuit breaker temperature.

[0037] Furthermore, such as Figure 2-4As shown, the temperature measuring device 4 in this embodiment also includes an electrical connection port 41 exposed on the outer surface of the current transformer body, enabling the temperature measuring device to acquire the measured temperature of external components of the current transformer. This electrical connection port 41 can be electrically connected to a second temperature measuring component (not shown), which can acquire the temperature at the junction of external components of the current transformer, such as the cable or copper busbar on the busbar side of a switchgear, where overheating is prone to occur. This electrical connection port 41 can be connected via a wire 42 to a data receiving and transmitting unit (e.g., a chip) of the temperature measuring device 4. This data receiving and transmitting unit can receive the temperature information acquired by the first and second temperature measuring components and can transmit the information (preferably wirelessly) to the outside.

[0038] In the current transformer of this embodiment, two temperature monitoring points are set up, and the temperature of the monitoring points can be acquired in real time. It can not only monitor the temperature inside the current sensor and the circuit breaker connected to it, but also monitor the temperature of external components such as busbar side components, and has a more accurate measurement effect on the components where the moving contact is located by contacting the stationary contact.

[0039] like Figure 3 and Figure 5-6 As shown, the primary conductor 3 may include a tubular portion 33 (e.g., a copper tube). At least its first temperature-measuring component in the temperature measuring device 4 is disposed on the inner wall of the free end, i.e., the first end 31, of the tubular portion. Preferably, the entire temperature measuring device 4 may be disposed within the inner wall of the free end of the tubular portion. This facilitates the arrangement and positioning of the temperature measuring device 4. The primary conductor 3 also includes an extension 34 (e.g., a copper busbar). One end of the extension 34 is connected to the tubular portion 33, and the other end forms the second end 32 of the primary conductor, wherein the second end is configured as a plate (in...). Figure 2 and 5 (This is clearly visible in the image). The second end of the plate, serving as an input or output terminal, allows for a larger connection area with external conductors. From... Figure 3 , 5 As can be seen from Figure 6, the conductor 42 extends along the tubular portion 33 and the extension portion 34 to the data receiving and transmitting unit of the temperature measuring device 4. This method is more conducive to the positioning of the conductor 42 during the casting process of the current transformer body 1.

[0040] In this embodiment, an additional secondary winding 6 is also provided, which serves as a power supply winding to power the temperature measuring device 4. Specifically, it draws power through electromagnetic induction and supplies the converted current to the data receiving and transmitting unit of the temperature measuring device 4. Figure 5 , 6 As shown, the additional secondary winding 6 can be disposed on the outer wall of the tubular portion 33 adjacent to the temperature measuring device 4.

[0041] In existing technology, a separate power-taking component is typically used to indicate the energized or de-energized state of the entire switching equipment. This component provides the capacitance value and is electrically connected to the indicator device on the dashboard. However, in the embodiments of this invention, the power-taking component 5 is integrated into the current transformer (which is attached to...). Figure 4 (As can be seen in the image). One end of the power-taking component 5 (e.g., a capacitor) is electrically connected to the primary conductor 3, and the other end is adapted to be electrically connected to an indicator device, such as an indicator light, that indicates the energized or de-energized state of the current transformer. Therefore, by integrating the power-taking component 5 into the current transformer, it is possible to avoid the need for additional power-taking components. Furthermore, since the power-taking component 5 is embedded within the insulating body of the current transformer, there is no need to provide additional insulating supports for the power-taking component, thus reducing the overall number of electrical components and lowering the complexity of the switching equipment. One or more shielding components may also be provided in the current transformer body 1 as needed, for example... Figure 3-6 The shielding component 7 is shown in the image.

[0042] The present invention also provides a switching device (not shown in the figure) including the current transformer. The primary conductor of the current transformer is connected to the circuit breaker of the switching device, for example, through a stationary contact at its first end, and the second end is connected, for example, to the copper busbar side or cable side of the feeder end. Due to the use of the current transformer, the switching device requires fewer electrical components, smaller internal space, and lower manufacturing costs. It can also monitor the temperature of the part of interest in real time and accurately, providing early warning in case of overheating, and eliminates the need for additional power-on status indicators.

[0043] Various modifications and variations can be made to the embodiments disclosed above without departing from the scope or spirit of the invention. Other embodiments of the invention will be apparent to those skilled in the art based on the practice of the invention disclosed in this specification. This specification and the examples disclosed herein should be considered illustrative only, and the true scope of the invention is defined by the appended claims and their equivalents.

Claims

1. A current transformer, characterized in that, The current transformer includes: The main body of the current transformer is formed by casting (1); A current conversion component (2) is embedded in the body (1) of a current transformer, the current conversion component including a primary winding and a secondary winding; A primary conductor (3) that supplies power to the primary winding includes a first end (31) and a second end (32), wherein either the first end (31) or the second end (32) is used as an input terminal of the current transformer and the other is used as an output terminal of the current transformer, and wherein the first end (31) is also configured as a stationary contact of the current transformer.

2. The current transformer according to claim 1, characterized in that, The current transformer also includes a temperature measuring device (4), which includes a first temperature measuring component that contacts the stationary contact.

3. The current transformer according to claim 2, characterized in that, The temperature measuring device (4) also includes an electrical connection port (41) exposed on the outer surface of the current transformer body, so that the temperature measuring device can obtain the temperature of the external components of the current transformer.

4. The current transformer according to claim 3, characterized in that, The primary conductor (3) includes a tubular portion (33), wherein the first end (31) is the free end of the tubular portion (33), and the first temperature measuring component is disposed on the inner wall of the free end of the tubular portion (33).

5. The current transformer according to claim 4, characterized in that, The primary conductor (3) further includes an extension (34), one end of which is connected to the tubular portion (33), and the other end of which forms the second end (32) of the primary conductor, wherein the second end is configured as a plate.

6. The current transformer according to claim 5, characterized in that, The temperature measuring device also includes a wire connected to the electrical connection port (41), the wire extending along the tubular portion (33) and the extension portion (34).

7. The current transformer according to any one of claims 2 to 6, characterized in that, The current conversion assembly also includes an additional secondary winding (6), wherein the additional secondary winding (6) supplies power to the temperature measuring device.

8. The current transformer according to any one of claims 1 to 6, characterized in that, The current transformer includes a cylindrical portion (11) that extends beyond the stationary contact and is integrally formed with the current transformer body (1).

9. The current transformer according to any one of claims 1 to 6, characterized in that, The stationary contact is configured to make contact with the moving contact of the circuit breaker of the switching equipment for electrical connection.

10. The current transformer according to any one of claims 1 to 6, characterized in that, The current transformer also includes a power taking component (5), one end of which is electrically connected to the primary conductor (3), and the other end is adapted to be electrically connected to an indicator device that indicates whether the current transformer is energized or de-energized.

11. A switching device, characterized in that, Includes the current transformer according to any one of claims 1-10.

12. The switching device according to claim 11, characterized in that, The electrical connection port (41) of the temperature measuring device of the current transformer is electrically connected to the second temperature measuring component, which is located on the cable or copper busbar on the bus side of the switchgear.

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