An internal fuse and power capacitor

Abstract

The present application relates to a kind of inner fuses and power capacitor, power capacitor includes shell, multiple inner fuses and multiple elements;Shell is enclosed to accommodate cavity, the inner wall of accommodating cavity is provided with core, and the core is connected with the inner wall of accommodating cavity by insulating impregnant;Element and inner fuse are alternately arranged along the height direction of shell, and inner fuse is connected in series with two adjacent elements;Inner fuse includes body and isolation plate;Isolation plate is provided with through slot, and body is arranged in through slot, and body is fixedly connected with isolation plate by fixing part;On the one hand, by setting body, effectively improve the impact ability of short-circuit high current, suitable for the power capacitor of large capacity element;On the other hand, by setting isolation plate, the influence of impact force on element when body generates fuse action is reduced;At the same time, the impurity carbide generated when body generates fuse action is sealed in through slot, avoid spreading to insulating impregnant and polluting insulating impregnant.

Description

Technical Field

[0001] This invention relates to the field of power capacitor technology, and in particular to an internal fuse and a power capacitor. Background Technology

[0002] Currently, due to material or manufacturing defects, it is difficult to avoid the existence of weak points in individual components within power capacitors, leading to premature breakdown. To address this issue, internal fuses are widely used as the first line of internal fault protection in power capacitor designs both domestically and internationally. During operation, if an individual component breaks down, the internal fuse connected in series with the broken component blows, quickly isolating the broken component. Aside from a minor capacitance loss, the entire power capacitor and even the entire capacitor bank can continue to operate normally, significantly improving the efficiency and reliability of the capacitor.

[0003] In recent years, the development of power capacitors has been driven by the introduction of advanced production equipment and technological advancements. To improve production efficiency, power capacitor components are trending towards larger capacities. According to standard GB / T11024.2 "Parallel Capacitors for AC Power Systems with Nominal Voltage Above 1kV - Part 4: Internal Fuses," the internal fuse of power capacitors must meet the following test requirements: 2.5U N (U N It does not fuse during short-circuit discharge (the same applies to the rated voltage); When the component breaks down under the lower limit voltage, the internal fuse reliably operates and blows. When the component breaks down under the upper limit voltage, the internal fuse reliably blows and the residual voltage at the break point is not less than 70% of the test voltage. Conventional internal fuses are generally made of copper with a single diameter ranging from Φ0.2 to Φ0.5 mm and a length ranging from 100 to 200 mm. The capacity of conventional internal fuse protection components is generally between 5 and 15 kvar. If the component capacity is increased further, conventional internal fuses cannot withstand the energy released by a short-circuit discharge of 2.5 kvar and will blow, thus failing to meet the standard requirements for internal fuses.

[0004] However, the current design capacity of individual power capacitor components has reached 30kvar, making conventional internal fuses unsuitable for large-capacity components. Summary of the Invention

[0005] In view of the shortcomings of the existing technology, the purpose of this invention is to provide an internal fuse and a power capacitor, which has the advantages of improving the ability to withstand short-circuit high current impact and solving the technical problem that internal fuses are not suitable for large-capacity components.

[0006] The above-mentioned objective of the present invention is achieved through the following technical solution: On one hand, the present invention provides an internal fuse, including a body and an isolation plate; a through groove is provided on the isolation plate, the body passes through the through groove, the body is fixedly connected to the isolation plate by a fixing member, and the fixing member covers the through groove; the body is used for melting to isolate the breakdown element.

[0007] Preferably, the internal fuse provided by the present invention includes a first electrode, a second electrode, and a protection unit. The protection unit is located between the first electrode and the second electrode. A first end of the protection unit is connected to the first electrode, and a second end of the protection unit is connected to the second electrode. The ends of the first electrode and the second electrode away from the protection unit both extend to the outside of the through groove.

[0008] Preferably, the internal fuse provided by the present invention includes a protection unit comprising multiple molten parts and multiple non-molten parts, wherein the molten parts and the non-molten parts are alternately arranged, and each non-molten part is connected at both ends to two adjacent molten parts; the two molten parts located at the beginning and end are respectively connected to the first electrode and the second electrode.

[0009] Preferably, the internal fuse provided by the present invention uses cardboard as the insulating plate.

[0010] Preferably, the insulating plate of the internal fuse provided by the present invention is made of polytetrafluoroethylene.

[0011] Preferably, in the internal fuse provided by the present invention, the fixing element is a wet adhesive tape.

[0012] Preferably, the inner fuse provided by the present invention has a cylindrical body.

[0013] Preferably, in the internal fuse provided by the present invention, the diameter of the molten part is smaller than the diameter of the first electrode or the second electrode.

[0014] Preferably, in the internal fuse provided by the present invention, the diameter of the molten part is smaller than the diameter of the non-molten part.

[0015] On the other hand, the present invention provides a power capacitor, including a housing, a plurality of internal fuses as described above, and a plurality of elements; the housing is configured to form a cavity, and a core is disposed on the inner wall of the cavity, the core being connected to the inner wall of the cavity by an insulating impregnating agent; the plurality of elements and the plurality of internal fuses are all housed within the cavity, the elements and the internal fuses are alternately arranged along the height direction of the housing, and the internal fuses are connected in series with two adjacent elements.

[0016] In summary, the beneficial technical effects of the present invention are as follows: The internal fuse and power capacitor provided in this application include a housing, multiple internal fuses, and multiple components; the housing surrounds a cavity, and a core is disposed on the inner wall of the cavity, the core being connected to the inner wall of the cavity through an insulating impregnating agent; multiple components and multiple internal fuses are all housed within the cavity, and the components and internal fuses are alternately arranged along the height direction of the housing, with each internal fuse connected in series with two adjacent components; the internal fuse includes a body and an insulating plate; a through groove is formed on the insulating plate. The main body is installed inside the through groove and is fixedly connected to the insulating plate by a fastener, which covers the through groove. The main body is used for fusing to isolate the broken-down component. On the one hand, by setting the main body, the impact resistance to short-circuit high current is effectively improved, making it suitable for power capacitors with large capacity components. On the other hand, by setting the insulating plate, the impact force of the main body when it generates the fuse is reduced on the component. At the same time, the impurities such as carbides generated when the main body generates the fuse are sealed in the through groove, preventing them from diffusing into the insulating impregnating agent and contaminating it. Attached Figure Description

[0017] Figure 1 This is a schematic diagram of the overall structure of the power capacitor provided in an embodiment of the present invention.

[0018] Figure 2 This is a schematic diagram of the overall structure of the internal fuse provided in an embodiment of the present invention.

[0019] Figure 3 This is a front view of the insulating plate in the internal fuse provided in an embodiment of the present invention.

[0020] Figure 4 This is a top view of the insulating plate in the internal fuse provided in an embodiment of the present invention.

[0021] Figure 5 This is a schematic diagram of the structure of the body in the internal fuse provided in an embodiment of the present invention.

[0022] In the figure, 1 is the power capacitor; 10 is the housing; 20 is the internal fuse; 201 is the body; 2011 is the first electrode; 2012 is the second electrode; 2013 is the protection unit; 2014 is the molten part; 2015 is the non-molten part; 202 is the insulating plate; 2021 is the through groove; 203 is the fixing part; 30 is the component; 40 is the core; 50 is the insulating impregnating agent; 60 is the sleeve; and 70 is the connecting bracket. Detailed Implementation

[0023] The present invention will be further described in detail below with reference to the accompanying drawings.

[0024] Reference Figure 1The present invention discloses a power capacitor 1, which includes a housing 10. The housing 10 is arranged to form an accommodating cavity. The cross-sectional shape of the accommodating cavity can be rectangular, rhomboid or other polygonal. This embodiment does not limit this.

[0025] For ease of explanation, the following description will use a rectangular cross-sectional shape for the accommodating cavity as an example.

[0026] In this embodiment, a core 40 is disposed on the inner wall of the accommodating cavity, and the core 40 is connected to the inner wall of the accommodating cavity through an insulating impregnating agent 50; the insulating impregnating agent 50 is disposed between the core 40 and the inner wall of the accommodating cavity, wherein the insulating impregnating agent 50 has insulating properties.

[0027] For example, the housing 10 may be made of stainless steel; of course, the housing 10 may also be made of other metals. In the embodiment where the housing 10 is made of stainless steel, the corrosion resistance of the housing 10 is improved, and the service life of the housing 10 is extended.

[0028] The top of the housing 10 is provided with two sleeves 60, which are spaced apart along the length of the housing 10. The bottom ends of the two sleeves 60 are inserted into the accommodating cavity and connected to the core 40.

[0029] Furthermore, in this embodiment, a plurality of connecting brackets 70 may be provided on the outer side wall of the housing 10. The plurality of connecting brackets 70 are spaced apart along the height direction of the housing 10. The connecting brackets 70 are used to connect the power capacitor 1 to the external device.

[0030] For example, the connecting bracket 70 may be U-shaped, and during use, one side of the connecting bracket 70 is connected to the outer wall of the housing 10.

[0031] The power capacitor 1 provided in this embodiment also includes a plurality of internal fuses 20 and a plurality of elements 30; the plurality of elements 30 and the plurality of internal fuses 20 are all housed in the accommodating cavity, and the elements 30 and the internal fuses 20 are alternately arranged along the height direction of the housing 10, and the internal fuses 20 are connected in series with two adjacent elements 30.

[0032] Specifically, two adjacent elements 30 are connected by an internal fuse 20, that is, the elements 30 and the internal fuse 20 are connected in series.

[0033] In this embodiment, when one of the components 30 of the power capacitor 1 is broken down, the internal fuse 20 connected in series with the broken component 30 melts to isolate the broken component 30 and ensure the normal operation of the power capacitor 1.

[0034] Continue to refer to Figures 2 to 5This embodiment provides an internal fuse 20, including a body 201 and an insulating plate 202. A through groove 2021 is provided on the insulating plate 202, and the body 201 passes through the through groove 2021. The body 201 is fixedly connected to the insulating plate 202 by a fixing member 203, which covers the through groove 2021. The body 201 is used for melting to isolate the broken-down element. By providing the insulating plate 202, the impact of the body 201's impact on the element 30 in the power capacitor 1 during fuse operation is reduced. Simultaneously, impurities such as carbides generated by the body 201 during fuse operation are sealed within the through groove 2021, preventing the carbides from diffusing into the insulating impregnating agent 50 and contaminating it. By providing the body 201, during use, the body 201 uses fuse operation to isolate the broken-down element 30 in the power capacitor 1.

[0035] By covering the through groove 2021 with the fastener 203, the fastener 203 is used to seal the through groove 2021, thereby preventing the body 201 from sliding out of the through groove 2021; at the same time, it prevents impurities generated when the body 201 fuses and diffuses into the insulating impregnating agent 50.

[0036] Specifically, the insulating plate 202 has insulating properties; wherein, the insulating plate 202 may be rectangular, rhomboid or other polygonal, and this embodiment does not limit it.

[0037] For ease of explanation, the following description uses a rectangular partition plate 202 as an example.

[0038] For example, the through groove 2021 may be formed at the middle position of the partition plate 202 extending along its width direction. Of course, the through groove 2021 may also be formed at the end position of the partition plate 202 extending along its width direction. In the possible implementation where the through groove 2021 is formed at the middle position of the partition plate 202 extending along its width direction, the through groove 2021 extends along the length direction of the partition plate 202, the body 201 extends along the length direction of the partition plate, the body 201 passes through the through groove 2021, and both ends of the body 201 extend to the outside of the through groove 2021 along the length direction of the partition plate.

[0039] The working principle of the internal fuse 20 provided in this embodiment is as follows: when a component 30 in the power capacitor 1 is broken down, the body 201 of the internal fuse 20 connected in series with the broken component 30 melts to isolate the broken component 30 in the power capacitor 1, thus ensuring the normal operation of the power capacitor 1.

[0040] Continue to refer to Figure 2 and Figure 5In this embodiment, the body 201 includes a first electrode 2011, a second electrode 2012, and a protection unit 2013. The protection unit 2013 is located between the first electrode 2011 and the second electrode 2012. The first end of the protection unit 2013 is connected to the first electrode 2011, and the second end of the protection unit 2013 is connected to the second electrode 2012. The ends of the first electrode 2011 and the second electrode 2012 that are away from the protection unit 2013 both extend to the outside of the through groove 2021. By setting the first electrode 2011 and the second electrode 2012, the first electrode 2011 and the second electrode 2012 are respectively used to connect with two adjacent components 30 to realize the series connection between the inner fuse 20 and the two adjacent components 30.

[0041] Specifically, the protection unit 2013, the first electrode 2011, and the second electrode 2012 all extend along the length of the insulating plate 202. During use, if any component 30 in the power capacitor 1 is broken down, the protection unit 2013 will fuse to isolate the broken component 30, ensuring the normal operation of the power capacitor 1.

[0042] Among them, with Figure 5 Taking the orientation shown as an example, the first electrode 2011 is located at the upper end of the protection unit 2013, and the second electrode 2012 is located at the lower end of the protection unit 2013.

[0043] Furthermore, in this embodiment, the protection unit 2013 includes multiple fusible portions 2014 and multiple non-fusible portions 2015. The fusible portions 2014 and non-fusible portions 2015 are alternately arranged along the extension direction of the through groove 2021, and the two ends of each non-fusible portion 2015 are respectively connected to two adjacent fusible portions 2014. The two fusible portions 2014 located at the beginning and end are respectively connected to the first electrode 2011 and the second electrode 2012. By providing multiple fusible portions 2014, the resistance of the body 201 to short-circuit high current impact is improved, so that the internal fuse 20 is suitable for the power capacitor 1 of the large-capacity component 30, and the application range of the internal fuse 20 is improved.

[0044] Specifically, both the molten portion 2014 and the non-molten portion 2015 extend along the length of the insulating plate 202. During use, when any element 30 in the power capacitor 1 is broken down, the molten portion 2014 in the inner fuse 20 connected in series with the broken element 30 activates the fuse, thereby quickly isolating the broken element 30 and ensuring the normal operation of the power capacitor 1.

[0045] For example, the body 201 is cylindrical; of course, the body 201 can also be plate-shaped. In the embodiment where the body 201 is cylindrical, the molten part 2014, the non-molten part 2015, the first electrode 2011, and the second electrode 2012 are all cylindrical. The central axes of the molten part 2014, the non-molten part 2015, the first electrode 2011, and the second electrode 2012 are all parallel. In some embodiments, the central axes of the molten part 2014, the non-molten part 2015, the first electrode 2011, and the second electrode 2012 are all collinear.

[0046] Furthermore, in a possible embodiment where the body 201 is cylindrical, the diameter of the molten portion 2014 is smaller than the diameter of the first electrode 2011 or the second electrode 2012. The diameter of the molten portion 2014 is also smaller than the diameter of the non-molten portion 2015.

[0047] For example, the insulating board 202 can be made of cardboard. Of course, the insulating board 202 can also be made of polytetrafluoroethylene (PTFE) sheet.

[0048] For example, the fastener 203 can be wet adhesive tape; of course, the fastener 203 can also be other objects with adhesive properties, as long as they are insulating and can fix the body 201 to the insulating plate 202.

[0049] In the feasible method of using wet adhesive tape for fastener 203, fastener 203 is adhered to the partition plate 202 and covers the through groove 2021, thereby preventing the body 201 from sliding out of the through groove 2021 and improving the firmness between the body 201 and the partition plate 202; by using wet adhesive tape for fastener 203, the ease of installation of the internal fuse 20 is improved.

[0050] The working principle of the internal fuse 20 provided in this application is as follows: when any element 30 in the power capacitor 1 is broken down, the molten part 2014 in the internal fuse 20 connected in series with the broken element 30 generates a fuse action, so that the broken element 30 is quickly isolated, and the impurities generated during the fuse action are completely sealed in the through groove 2021.

[0051] The power capacitor 1 provided in this application includes a housing 10, a plurality of internal fuses 20, and a plurality of components 30. The housing 10 is configured to form a cavity, and a core 40 is disposed on the inner wall of the cavity. The core 40 is connected to the inner wall of the cavity through an insulating impregnating agent 50. The plurality of components 30 and the plurality of internal fuses 20 are all housed in the cavity. The components 30 and the internal fuses 20 are alternately arranged along the height direction of the housing 10. The internal fuse 20 is connected in series with two adjacent components 30. The internal fuse 20 includes a body 201 and an insulating plate 202. A through groove 2021 is formed on the insulating plate 202, and the body 201 passes through the through groove 2021. The main body 201 is fixedly connected to the insulating plate 202 via the fastener 203, which covers the through groove 2021. The main body 201 is used for fusing to isolate the broken-down component. On the one hand, by setting the main body 201, the impact resistance to short-circuit high current is effectively improved, making it suitable for the power capacitor 1 of the large-capacity component 30. On the other hand, by setting the insulating plate 202, the impact of the impact force on the component 30 when the main body 201 generates the fuse is reduced. At the same time, the impurities such as carbides generated when the main body 201 generates the fuse are sealed in the through groove 2021 to prevent them from diffusing into the insulating impregnating agent 50 and contaminating the insulating impregnating agent 50.

[0052] It should be noted that, in this document, relational terms such as "first" and "second" are used merely to distinguish one entity or operation from another, and do not necessarily require or imply any such actual relationship or order between these entities or operations. Furthermore, the terms "comprising," "including," or any other variations thereof are intended to cover non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements includes not only those elements but also other elements not expressly listed, or elements inherent to such a process, method, article, or apparatus. Without further limitation, an element defined by the phrase "comprising one..." does not exclude the presence of other identical elements in the process, method, article, or apparatus that includes said element.

[0053] Finally, it should be noted that the above embodiments are merely examples for clearly illustrating the present invention and are not intended to limit the implementation. Those skilled in the art will recognize that other variations or modifications can be made based on the above description. It is neither necessary nor possible to exhaustively list all possible implementations. However, obvious variations or modifications derived therefrom are still within the scope of protection of this invention.

Claims

1. An internal fuse, characterized in that: Including the main body and the insulation plate; The isolation plate has a through groove, the main body passes through the through groove, the main body is fixedly connected to the isolation plate by a fastener, and the fastener covers the through groove; The body is used for melting to isolate the breakdown element; The body includes a first electrode, a second electrode, and a protection unit. The protection unit is located between the first electrode and the second electrode. A first end of the protection unit is connected to the first electrode, and a second end of the protection unit is connected to the second electrode. The ends of both the first electrode and the second electrode that are away from the protection unit extend to the outside of the through slot; The protection unit includes multiple molten parts and multiple non-molten parts, which are alternately arranged along the extension direction of the through groove, and the two ends of each non-molten part are respectively connected to two adjacent molten parts. The two melt sections located at the beginning and end are respectively connected to the first electrode and the second electrode.

2. The internal fuse according to claim 1, characterized in that: The partition board is made of cardboard.

3. The internal fuse according to claim 1, characterized in that: The insulation board is made of polytetrafluoroethylene (PTFE).

4. The internal fuse according to claim 1, characterized in that: The fastener is made of wet adhesive tape.

5. The internal fuse according to claim 1, characterized in that: The body is cylindrical.

6. The internal fuse according to claim 5, characterized in that: The diameter of the melt portion is smaller than the diameter of the first electrode or the second electrode.

7. The internal fuse according to claim 5, characterized in that: The diameter of the molten part is smaller than the diameter of the non-molten part.

8. A power capacitor, characterized in that: It includes a housing, multiple internal fuses as described in any one of claims 1 to 7, and multiple components; The housing is configured to form a cavity, and a core is disposed on the inner wall of the cavity. The core is connected to the inner wall of the cavity by an insulating impregnating agent. Multiple elements and multiple internal fuses are housed within the accommodating cavity. The elements and internal fuses are alternately arranged along the height direction of the housing. The internal fuses are connected in series with two adjacent elements.

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