Discharge device and power capacitor having it

Abstract

This utility model relates to a discharge device comprising at least one discharge resistor and a resistor protection plate for clamping the discharge resistor therein. The device includes: a hollow rectangular first protection plate; a hollow rectangular mounting plate; and a hollow rectangular second protection plate, wherein the first protection plate, mounting plate, and second protection plate are stacked sequentially to define a cavity within which the discharge resistor is housed, defined by the first, second, and third hollow portions. Thus, the discharge device can be disposed within a relatively confined space within the casing of a power capacitor, regardless of the orientation of the power capacitor itself. Simultaneously, since the discharge resistor is protected in all directions by the first and second protection plates, the reliability of the capacitor is significantly improved, preventing capacitor failure. The invention also relates to a power capacitor having the above-described discharge device.

Description

Technical Field

[0001] This utility model relates to the field of power equipment technology, and in particular to a novel discharge device and a power capacitor having such a discharge device, thereby preventing the power capacitor from failing due to the displacement or fall of the discharge resistor during transportation or resetting. Background Technology

[0002] It is known that power capacitors are used in power grids for power factor correction, improving voltage stability, and regulating the low power transmission efficiency caused by inductive components in circuit transmission. Due to power grid pollution, power capacitors are now widely used for filtering. When a power capacitor is disconnected from the power grid, the charge on the capacitor is not discharged, which can easily lead to electric shock. Therefore, when a power capacitor is disconnected from the power grid, a discharge device must be used to immediately discharge the remaining charge on the capacitor; this is a requirement for the safe use of power capacitors. Specifically, after unplugging the power cord, large-capacity power capacitors will have residual voltage. National safety standards "GB4706.1 Safety of Household and Similar Electrical Appliances" or "IEC60335-1" have mandatory requirements for such residual voltage, namely, after unplugging the power cord, the residual voltage of the power capacitor must be reduced to below 34V within 1 second.

[0003] To address this, Chinese invention patent application publication number CN106849043A discloses an active discharge circuit and discharge device, which consists of a discharge resistor, a capacitor, a bidirectional diode, and a bidirectional thyristor. This discharge device can discharge rapidly and has low power consumption in the power grid. However, the discharge resistor in this device is designed as a glass glaze resistor.

[0004] This leads to the following drawbacks: Due to the flat design and large size of the glass glaze resistor, it is difficult to reliably fix it in the limited space of the power capacitor. In practice, improper horizontal or vertical placement of the power capacitor often causes the glass glaze resistor to shift or even fall off, which can then short-circuit with the internal components or shell of the power capacitor, resulting in damage to the discharge resistor or the entire high-voltage capacitor. This makes the failure rate of this type of discharge device relatively high, and may even cause further accidents in the high-voltage power system, resulting in huge losses of personnel and property, and posing hazards and hidden dangers to the power supply system.

[0005] Therefore, there is a technical need in the art to provide a discharge device that can fix the discharge resistor in a more reliable manner, thereby allowing the discharge device to be fixed inside the housing of the power capacitor regardless of the installation direction of the power capacitor, with virtually no risk of short circuit between the resistor and the internal components or housing of the power capacitor. Utility Model Content

[0006] The present invention aims to provide a discharge device that can at least solve some of the above-mentioned problems, wherein the discharge device has a simple structure, is economical in cost and has high operational reliability.

[0007] According to one aspect of the present invention, a discharge device is provided, which is electrically connected to two output terminals of a power capacitor, characterized in that it includes at least one discharge resistor and a resistor protection plate for clamping the discharge resistor therein, wherein the resistor protection plate includes: a hollow rectangular first protection plate, which includes a centrally arranged interval portion within the hollow rectangle and two first hollow portions located on both sides of the interval portion; a hollow rectangular mounting plate, which includes a centrally arranged interval portion within the hollow rectangle and two third hollow portions located on both sides of the interval portion; and a hollow rectangular second protection plate, which includes a centrally arranged interval portion within the hollow rectangle and two second hollow portions located on both sides of the interval portion; wherein the first protection plate, the mounting plate, and the second protection plate are stacked sequentially to define a cavity for accommodating the discharge resistor therein by the first hollow portions, the second hollow portions, and the third hollow portions.

[0008] Therefore, compared with existing discharge devices, the discharge device according to this invention can be installed in a fairly confined space within the casing of the power capacitor, regardless of the capacitor's orientation. Even if the power capacitor is subjected to external disturbances, such as impacts or changes in orientation or shaking during transportation, the discharge resistor in this discharge device will not shift or even detach. Furthermore, since the discharge resistor is protected in all directions by the first and second protective plates, the reliability of the capacitor is significantly improved, preventing capacitor failure.

[0009] As a preferred aspect, the first protective plate, mounting plate, and second protective plate are designed to have the same dimensions, wherein the rectangle has a longitudinal length between 75 mm and 90 mm and a lateral width between 45 mm and 55 mm. This allows for manufacturing at a lower cost.

[0010] In a preferred aspect, the spacers in the first protective plate, the mounting plate, and the second protective plate have the same dimensions, and the spacers have a width between 5 mm and 8 mm.

[0011] As a preferred aspect, the first hollow portion, the second hollow portion, and the third hollow portion have the same dimensions, wherein the first hollow portion, the second hollow portion, and the third hollow portion have a length of 60 mm to 70 mm and a width of 12 mm to 16 mm.

[0012] As a preferred aspect, the mounting plate further includes a first wire guide groove and a second wire guide groove located at its opposite ends for accommodating the wiring at both ends of the discharge resistor.

[0013] As a preferred embodiment, the discharge resistor is designed as a ceramic carbon film resistor with an insulating sleeve, and the first protection plate, mounting plate, and second protection plate are integrally molded from electrically insulating engineering plastic. This allows for manufacturing at a lower cost.

[0014] As a preferred aspect, the discharge device further has a first terminal and a second terminal located on opposite sides thereon, wherein the discharge device is housed within the casing of the power capacitor via a first electrical connection located between the first terminal and one output terminal of the power capacitor and a second electrical connection located between the second terminal and the other output terminal of the power capacitor.

[0015] In a preferred embodiment, the discharge device is arranged to be parallel and spaced apart from the capacitor core of the power capacitor.

[0016] In another aspect of this utility model, a power capacitor is also disclosed, comprising a housing and a plurality of capacitor cores and a discharge device located within the housing, wherein the plurality of capacitor cores are connected in parallel to each other to form a parallel circuit, wherein the two ends of the parallel circuit are electrically connected to the output terminals of the power capacitor, characterized in that the discharge device is the aforementioned discharge device.

[0017] In a preferred embodiment, the capacitor core comprises eight capacitor elements, and each capacitor core is electrically connected to an equalizing resistor at both ends. Attached Figure Description

[0018] The following figures are intended only to illustrate and explain the present invention and do not limit the scope of the present invention.

[0019] Figure 1 This is a perspective view showing an embodiment of the discharge device according to the present invention, wherein the discharge resistor has been removed to better show the details;

[0020] Figure 2 It shows Figure 1 A plan view of the protection plate of the discharge device in the middle;

[0021] Figure 3 This is a front view of the discharge device according to the present invention, wherein part of the mounting plate has been removed to better show the details;

[0022] Figure 4 This shows a side view of the discharge device according to the present invention;

[0023] Figure 5 This is a front view showing a cross-section of a power capacitor according to the present invention, with a discharge device according to the present invention, wherein part of the mounting plate has been removed to better show the details.

[0024] Explanation of reference numerals in the attached figures:

[0025] 100. Discharge device; 101. First protection plate; 102. Mounting plate; 103. Second protection plate;

[0026] 104A. First wire guide groove; 104B. Second wire guide groove; 105A. First hollow section;

[0027] 105B. Second hollow section; 105C. Third hollow section; 106A. First terminal;

[0028] 106B. Second terminal; 107A. First electrical connection; 107B. Second electrical connection;

[0029] 200. Discharge resistor; 300. Power capacitor; L. Longitudinal length; W. Lateral width;

[0030] l. Length of the hollow section; H. Width of the hollow section; d. Width of the spacer; h. Spacing between the hollow sections. Detailed Implementation

[0031] The schematic scheme of the discharge device disclosed in this utility model will now be described in detail with reference to the accompanying drawings. Although the drawings are provided to illustrate some embodiments of this utility model, the drawings are not necessarily drawn to the dimensions of the specific embodiments, and certain features may be enlarged, removed, or partially cut to better illustrate and explain the disclosure of this utility model. Some components in the drawings may be repositioned according to actual needs without affecting the technical effect. The phrase "in the drawings" or similar terms appearing in the specification do not necessarily refer to all drawings or examples.

[0032] Certain directional terms used in the description of the accompanying drawings below, such as “inner,” “outer,” “above,” “below,” and other directional terms, will be understood to have their normal meaning and refer to those directions as normally viewed in the accompanying drawings. Unless otherwise specified, the directional terms used in this specification are generally in accordance with the conventional directions understood by those skilled in the art.

[0033] The terms “first,” “first,” “second,” “second,” and similar terms used in this utility model do not indicate any order, quantity, or importance, but are used to distinguish one component from other components.

[0034] The terms "joining", "connection" and similar terms used in this utility model include both indirect connection of two components with the aid of an intermediate layer such as an adhesive or welding agent or an intermediate component such as a connector or transition piece, and direct connection of two components without the aid of any intermediate layer such as an adhesive or welding agent or an intermediate component such as a connector or transition piece.

[0035] The power capacitor 300 according to this utility model includes a housing, multiple capacitor cores, and multiple discharge devices 100. For example... Figure 5 As shown, here for example, the capacitor cores are divided into two parallel capacitor cores from right to left (each capacitor core includes several parallel capacitor elements, the number of which can be set according to actual needs). Figure 5 The example in the text shows 8 capacitor elements; therefore, in this embodiment, each capacitor core includes 8 capacitor elements, and the two capacitor cores (including capacitor elements numbered 1 to 16 in sequence) and preferably two discharge devices 100 are all disposed within the housing of the power capacitor 300. The housing 1 can, for example, be welded from a sealed stainless steel plate, and the surface of the housing 1 is coated with flame-retardant paint. The number of capacitor cores can be determined according to the actual required rated voltage. In this embodiment, the power capacitor 300 includes 2 capacitor cores, each of which includes 8 capacitor elements. These two capacitor cores are, for example, connected in parallel to form a parallel circuit. The two ends of this parallel circuit are connected to the output terminals of the power capacitor 300 (in...). Figure 5 (not shown in the image) is an electrical connection.

[0036] To discharge the remaining charge in the capacitor core to a safe voltage, the first electrical connection 107A and the second electrical connection 107B, respectively led out from the first terminal 106A and the second terminal 106B on opposite sides of the discharge device 100, are also electrically connected to the output terminals. That is, the discharge device 100 is also connected between the two output terminals of the power capacitor. To ensure that the voltage of the two capacitor cores is equal, it is preferable to connect an equalizing resistor in parallel across both ends of each capacitor core; therefore, in this embodiment, the number of equalizing resistors is 16. During the operation of the power capacitor 300, the equalizing resistors also isolate faulty components and protect the power capacitor 300, preventing the entire power capacitor 300 from failing due to a fault in an individual capacitor core 2.

[0037] like Figure 5As shown, in this embodiment, the power capacitor 300 is placed vertically, and the capacitor cores corresponding to which the discharge device 100 is electrically connected are arranged in parallel intervals; that is, the discharge device 100 and the capacitor cores are also arranged in parallel intervals. Similarly, it is also possible to change the power capacitor 300, which is shown here in a vertically placed state, to a horizontal or lay-down state, depending on the arrangement space of the power capacitor 300 in the power system and other technical requirements. Those skilled in the art will understand that even when the power capacitor 300 is in a horizontal or lay-down state, the capacitor cores corresponding to which the discharge device 100 is electrically connected are still arranged in parallel intervals. That is, the orientation of the discharge device 100 itself is independent of the placement state of the power capacitor 300.

[0038] exist Figures 3 to 5 The diagram illustrates a discharge device 100 according to the present invention. As an example, the discharge device 100 exemplary includes two sets of two discharge resistors 200 connected in parallel. It should be noted that the number of discharge resistors 200 in the discharge device 100 can be set according to actual needs, and is not limited to the two in this embodiment; it can be three, four, or even more. Preferably, the discharge resistors 200 shown here are designed as small-volume, elongated cylindrical ceramic carbon film resistors for easy assembly and reliable connection. To avoid the risk of short-circuiting between the two parallel resistors, an insulating sleeve matching the resistance size is fitted over the outside of each discharge resistor (in...). Figure 3 (Shown as a cross-section). In this embodiment, an insulating sleeve is fitted over each discharge resistor 200. On one hand, the insulating sleeve protects the resistor. On the other hand, when the ceramic carbon film resistor is damaged, small fragments may fall out, and the insulating sleeve helps prevent these fragments from contaminating other components in the high-voltage capacitor. As a feasible option, the insulating sleeve is made of crepe paper.

[0039] like Figure 3 and 4 As shown in the diagram, the leads of the two parallel-connected discharge resistors 200 at their two opposite ends are connected together and then respectively via leads located at... Figure 3 The first terminal 106A above and located at Figure 3 The second terminal 106B below, then as follows Figure 5 As shown, the first terminal 106A is then electrically connected to the output terminal of the power capacitor 300 via a first electrical wire 107A connected in series therewith, and at the same time, the second terminal 106B is then electrically connected to the output terminal of the power capacitor 300 via a second electrical wire 107B connected in series therewith.

[0040] exist Figure 1and Figure 2 The image shows a resistor protection plate, which is part of the discharge device 100, wherein, as shown... Figure 1 As shown, the resistor protection board includes a first protection board 101, a mounting plate 102, and a second protection board 103 stacked sequentially. Preferably, the first protection board 101, the mounting plate 102, and the second protection board 103 have substantially the same external dimensions and structure, thereby allowing for manufacturing at a lower cost.

[0041] like Figure 2 As shown, the external dimensions and structure of the first protective plate 101 are described here as an example. The first protective plate 101 is generally a hollow rectangle, with a longitudinal length L (preferably 80 mm) of approximately 75 mm to 90 mm and a transverse width W (preferably 50 mm) of approximately 45 mm to 55 mm. Inside the hollow rectangle, there is a centrally located spacer of width d, designed to be approximately 5 to 8 mm wide, preferably 6 mm. As a result, two first hollow portions 105A of substantially the same size are defined on either side of the spacer of width d in the first protective plate 101. These first hollow portions 105A will subsequently be used to suspend and insulate the discharge resistor 200. Each first hollow portion 105A has a length l (preferably 65 mm) of approximately 60 mm to 70 mm and a width of approximately 12 to 16 mm (preferably 14 mm).

[0042] Meanwhile, to ensure that the first protective plate 101 has sufficient structural strength and electrical insulation performance, the distance h between the side edge of the first hollow portion 105A and the side edge of the first protective plate 101 is designed to be between 7 mm and 10 mm, preferably 8 mm. The first protective plate 101 can be integrally molded from electrically insulating engineering plastic by means of molding or injection molding.

[0043] Turn Figure 1 It can be seen that below the first protection plate 101, there are also, in sequence, a mounting plate 102 for actually accommodating the discharge resistor 200 and a second protection plate 103 for sandwiching the mounting plate 102 between the first protection plate 101 and the first protection plate 101. Figure 1 As shown, the mounting plate 102 and the second protective plate 103 are also provided with the same second hollow portion 105B and the third hollow portion 105C as the first protective plate 101 and are interconnected. Additionally, the mounting plate 102 also has a first wire groove 104A and a second wire groove 104B at the central position located at its two opposite ends for accommodating the wiring at both ends of the discharge resistor 200.

[0044] exist Figure 3 and 4The diagram shows the working state of the assembled resistor protection board with discharge resistors 200, at which point the discharge resistors 200 and the resistor protection board together form the discharge device 100 according to this utility model.

[0045] like Figure 3 As shown, the main body of the discharge resistor 200 is housed within the third hollow portion 105C of the mounting plate 102, and the wiring on both sides is housed within the first wire guide groove 104A and the second wire guide groove 104B of the mounting plate 102. Since the mounting plate 102 is made of electrically insulating material and the discharge resistor 200 is suspended within the third hollow portion 105C, and subsequently the mounting plate 102... Figure 4 As shown, it is covered on its opposite sides by a first protective plate 101 and a second protective plate 103 made of electrical insulating material, which makes the discharge resistor 200 located in the resistor protection plate fixedly held in the cavity defined by its first hollow portion 105A, second hollow portion 105B and third hollow portion 105C, and physically and electrically isolated from the components in the power capacitor 300 in any direction in the space.

[0046] As a result, the discharge device 100 according to this invention can be disposed in a fairly confined space within the housing of the power capacitor 300, regardless of the orientation of the power capacitor 300 itself. Even if the power capacitor 300 is subjected to external disturbances, such as impacts or changes in its orientation or shaking during transportation, the discharge resistor 200 in the discharge device 100 will not shift or even fall off. Simultaneously, since the discharge resistor 200 is protected in all directions by the first protection plate 101 and the second protection plate 103, the reliability of the capacitor is significantly improved, preventing capacitor failure.

[0047] The preferred embodiments of the present invention have been described above, and the features in these embodiments may be interchanged, substituted, or combined.

[0048] It should be understood that although this specification describes various embodiments, not every embodiment contains only one independent technical solution. This way of describing the specification is only for clarity. Those skilled in the art should regard the specification as a whole. The technical solutions in each embodiment can also be appropriately combined to form other implementation methods that can be understood by those skilled in the art.

[0049] The above description is merely an illustrative embodiment of this utility model and is not intended to limit the scope of this utility model. Any equivalent changes, modifications, and combinations made by those skilled in the art without departing from the concept and principles of this utility model should fall within the protection scope of this utility model.

Claims

1. A discharge device electrically connected to both outgoing terminals of a power capacitor, characterized in that It includes at least one discharge resistor and a resistor protection plate for clamping the discharge resistor therein, wherein the resistor protection plate includes: A first protective plate is a hollow rectangle, comprising a spacer centrally located within the hollow rectangle and two first hollow portions located on either side of the spacer. A hollow rectangular mounting plate includes a centrally located spacer within the hollow rectangle, and two third hollow portions located on either side of the spacer; and The second protective plate is a hollow rectangle, which includes a spacer centrally located within the hollow rectangle and two second hollow portions located on both sides of the spacer. The first protection plate, the mounting plate, and the second protection plate are stacked together in sequence, so that the first hollow part, the second hollow part, and the third hollow part together define a cavity in which the discharge resistor is housed.

2. The electrical discharge device of claim 1, wherein the dielectric material is a ceramic material. The first protective plate, the mounting plate, and the second protective plate are designed to have the same dimensions, wherein the rectangle has a longitudinal length between 75 mm and 90 mm and a lateral width between 45 mm and 55 mm.

3. The electrical discharge device of claim 2, wherein the dielectric material is a ceramic material. The spacers in the first protective plate, the mounting plate, and the second protective plate have the same dimensions, and the spacers have a width between 5 mm and 8 mm.

4. The electrical discharge device of claim 3, wherein the dielectric material is a ceramic material. The first hollow portion, the second hollow portion, and the third hollow portion have the same dimensions, wherein the first hollow portion, the second hollow portion, and the third hollow portion have a length of 60 mm to 70 mm and a width of 12 mm to 16 mm.

5. The electrical discharge device of claim 1, wherein the dielectric material is a ceramic material. The mounting plate also includes a first wire guide groove and a second wire guide groove located at its opposite ends for accommodating the wiring at both ends of the discharge resistor.

6. The electrical discharge device of claim 1, wherein the dielectric material is a ceramic material. The above The discharge resistor is designed as a ceramic carbon film resistor with an insulating sleeve, and the first protection plate, the mounting plate, and the second protection plate are integrally molded from electrically insulating engineering plastic.

7. The electrical discharge device of claim 1, wherein the dielectric material is a ceramic material. The discharge device also has a first terminal and a second terminal located on opposite sides thereon, wherein the discharge device is housed within the casing of the power capacitor via a first electrical connection located between the first terminal and one output terminal of the power capacitor and a second electrical connection located between the second terminal and the other output terminal of the power capacitor.

8. The discharge device as claimed in claim 7, characterized in that, The discharge device is arranged parallel to and spaced apart from the capacitor core of the power capacitor.

9. A power capacitor comprising a housing and a plurality of capacitor cores and a discharge device located within the housing, wherein the plurality of capacitor cores are connected in parallel to form a parallel circuit, wherein the two ends of the parallel circuit are electrically connected to the output terminals of the power capacitor, characterized in that, The discharge device described therein is the discharge device according to any one of claims 1 to 8.

10. The power capacitor as claimed in claim 9, characterized in that, The capacitor core comprises eight capacitor elements, and each capacitor core is electrically connected to a voltage equalization resistor at both ends.

Images