Moisture-proof electrical insulators for power transmission and distribution

Abstract

[Solution] A composite insulator is provided for use in power distribution and transmission, the composite insulator comprising: a rod including a core rod and a housing covering the core rod; and a plurality of sheds, at least one shed having a smaller diameter and at least one shed having a larger diameter and positioned above the shed with the smaller diameter, the shed with the larger diameter including a downwardly extending peripheral lip.

Description

[Technical Field]

[0001] The technology relates to a robust insulator suitable for use in coastal and shoreline areas. More specifically, the technology is a composite insulator that includes at least one lipped shed that blocks and expels moisture, thereby reducing the buildup of pollutants and algae. [Background technology]

[0002] Electrical distribution and transmission line insulators, post insulators, suspension insulators, bushings, and fuse cutouts all must withstand exposure to harsh environmental conditions, including extreme temperatures, icing, snow accumulation, high humidity, road salt spray, and rain. Coastal and shoreline areas and polluted regions provide some of the more severe environments, as one or more of humidity, sea spray, lake spray, and rain promote algae growth due to moisture penetration into polymeric and composite insulators. This growth, in turn, rapidly degrades the polymeric surfaces of these electrical insulators.

[0003] U.S. Patent Application Publication No. 20180106850 discloses a composite insulator (1) for overhead power lines, comprising a rigid core extending axially between two fixtures (6) and a shell having sheds (5, 5') made of an electrically insulating synthetic material disposed thereon. The insulator includes a detector device for detecting surface leakage currents, the detector device including a conductive metal annular ring (7) surrounding the shell between an end shed (5') adjacent to one of the two fixtures (6) and another shed (5) adjacent to the end shed (5') and extending radially above the ring (7). The rings (7) are connected by a conductive wire (8) that passes through the end shed (5') and is connected to an electronic unit (9) of the detector device. This prior art document does not address the issue of water and water damage.

[0004] U.S. Patent Application Publication No. 20180106846 discloses an overhead power line insulator including a dielectric element (4) having an outer surface forming a skirt (5) with a head extended by a metallic fixture (7) for mounting the insulator, and a device for detecting surface leakage current flowing on the dielectric (4), the device including a conductive ring (8) surrounding the fixture (7) and in contact with the outer surface of the dielectric (4). An electrically insulating protective element (10) is provided in the form of a collared bushing surrounding the fixture (7), interposed between the ring (8) and the fixture (7), and extending radially over the ring (8) to protect the ring (8) from environmental contamination. This prior art document does not address the issue of water and water damage.

[0005] U.S. Patent Application Publication No. 20060081394 discloses methods for applying lotus effect materials as (superhydrophobic) protective coatings for external electrical insulation systems, as well as methods for fabricating / manufacturing lotus effect coatings. Selected inorganic or polymeric materials can be applied to the surface of the insulating material to produce a stable superhydrophobic coating. Various UV stabilizers and UV absorbers can be incorporated into the coating system to enhance the UV stability of the coating. This prior art document, more specifically for power lines, promotes water evacuation from the surface while removing dirt and debris along with the water.

[0006] U.S. Patent Application Publication No. 20050034892 discloses a composite insulator including a means for providing early warning of impending failure due to stress corrosion cracking, flash-under, or rod fracture due to discharge activity conditions. The composite insulator, which includes a fiberglass rod enclosed in a polymer housing and attached to metal end fittings on both ends of the rod, is doped with a dye-based chemical dopant. The dopant is disposed near the outer surface of the fiberglass rod. The dopant has migration and diffusion properties that correlate with those of water, is inert in a dry state, and is formulated to be compatible with the components of the insulator. Because the dopant is disposed within the insulator, when moisture penetrates from the housing to the rod through a permeation path on the insulator's outer surface, the dopant becomes activated and leaches out through the same permeation path. The activated dopant then forms a deposit or stain on the outer surface of the insulator housing. The dopant is sensitive to one or more specific wavelengths of radiation or contains a visually identifiable dye. The activated dopant deposits on the outer surface of the insulator can be detected by imaging the outer surface of the insulator with an appropriate imaging device or with the naked eye. Although this prior art document warns of the presence of moisture within the insulator, it does not address reducing or eliminating the moisture within the insulator.

[0007] U.S. Patent No. 5,847,325 discloses a composite insulator suitable for high voltage outdoor use, comprising an inner structural rod of electrically insulating material; and an outer coating formed from a thermoplastic material having a plurality of radially extending sheds integrally formed therewith, the outer coating terminating adjacent an end of the inner rod, the outer coating having at least two radially extending abutment surfaces configured to abut mating abutment surfaces formed on an end fitting. The insulator offers excellent mechanical properties while being lightweight and meeting all electrical requirements.

[0008] U.S. Patent No. 5,877,453 discloses a composite insulator having a silicone rubber sheath covering an insulator rod between metal fittings. Adjacent to the line fittings, at least one series of weather sheds are attached to the rod and secured to the sheath with their hubs in abutting relationship and one hub in abutment against the line fitting. Another series of sheds are spaced apart from each other and from the previous series of weather sheds with their hubs in abutting relationship. One objective of this prior art document is to reduce water droplet corona discharge and associated aging and corrosion, but this prior art document does not alleviate the problem.

[0009] Fengcheng Lu, Leilei Niu, Shenghui Wang, Tingyue Jiang, Wei Li, Jiayi Guo, and Hao Li (first published February 19, 2021, https: / / doi.org / 10.1049 / iet-smt.2019.0558) show that water droplets on grading rings reduce corona discharge but do not completely eliminate it. Furthermore, grading rings do not prevent water droplets from forming on the insulator.

[0010] European Patent No. 0278606 discloses a high-performance high-voltage electrical insulator for use above 15 kV in wet and contaminated conditions, designed to minimize surface area while keeping leakage current low by specifying the ratio of shed diameter to shed pitch, the ratio of leakage distance between support connectors to linear distance between support connectors, and the ratio of shed diameter to support rod diameter. Insulators that meet the design specifications by using specified silicone elastomer compositions, or by using silicone compositions that meet specified electrical properties, have been shown to be useful high-voltage insulators.

[0011] What is needed are composite insulators, bushings, or fuse cutouts suitable for areas with high rainfall and / or high humidity. It would be preferable if they were also suitable for highly polluted areas. It would be preferable if they reduced algae buildup and the resulting deterioration of surface materials. It would be preferable if they were easy to manufacture. Summary of the Invention

[0012] The technology is a composite insulator, bushing, or fuse cutout suitable for areas with high rainfall and / or high humidity. The technology is also suitable for areas with high levels of pollution. It is particularly useful in coastal environments where fouling of the insulator by biological organisms is particularly problematic. The technology is easy to manufacture by injection molding. The insulators of the technology are used to reduce or eliminate algae growth, reduce or eliminate contaminant retention, and expel moisture.

[0013] In another embodiment, an insulator for use in electrical power transmission and distribution is provided, the insulator comprising: a rod including an inner surface defining a bore; a core rod housed within the bore; a plurality of sheds contiguous with and extending outwardly from the rod; at least one shed having a smaller diameter and at least one shed having a larger diameter and positioned above the smaller diameter sheds, the larger diameter sheds having a downwardly extending peripheral lip.

[0014] The insulator is provided with a series of sheds, which may alternate between larger diameter sheds and smaller diameter sheds.

[0015] The insulator may further include a housing that encases the core rod.

[0016] In the present insulator, the housing and shed may comprise silicone.

[0017] In the insulator, the core rod may include a glass fiber reinforced polymer.

[0018] The insulator may be a suspension insulator.

[0019] The insulation may be a line insulation.

[0020] The insulator may be a post insulator.

[0021] The insulator may be configured for use in a fuse cutout.

[0022] In the insulator, the core rod may be a conductive rod.

[0023] The insulator may further comprise an insulating layer in the bore between the core rod and the inner surface of the rod.

[0024] The insulator may be a bushing.

[0025] In the insulator, the rods and sheds may comprise a composite material.

[0026] In the present insulator, the rods and sheds may be injection molded.

[0027] In one embodiment, a composite insulator is provided for use in distribution lines (below 69 kV) and transmission lines (above 69 kV), the composite insulator comprising: a rod including a core rod and a housing covering the core rod; and a plurality of sheds, at least one shed having a smaller diameter and at least one shed having a larger diameter and positioned above the smaller diameter sheds, the larger diameter sheds comprising a peripheral lip.

[0028] The composite insulator may be provided with a series of sheds, the series of sheds alternating between larger diameter sheds and smaller diameter sheds.

[0029] In the composite insulator, the housing and the shed may comprise silicone.

[0030] The composite insulator may be a suspension insulator, a line insulator, or a post insulator.

[0031] In another embodiment, a method for manufacturing a monolithic article for use in an insulator is provided, the monolithic article comprising a rod and a series of sheds, at least one shed having a downwardly extending peripheral drip bead, the method including the steps of providing a mold; injecting a composite material into the mold; and removing the rod and the series of sheds from the mold.

[0032] In another embodiment, a method for reducing algae growth on a composite insulator is provided, the method including the steps of selecting a composite insulator comprising: a rod including a core rod and a housing covering the core rod; and a plurality of sheds, at least one shed having a smaller diameter and at least one shed having a larger diameter and positioned over the smaller diameter sheds, the larger diameter shed including a peripheral lip; and attaching the composite insulator to both the transmission line and the transmission line support or to both the distribution line and the distribution line support.

[0033] In this manner, the composite insulator may be positioned substantially vertically. [Brief explanation of the drawings]

[0034] [Figure 1] 1 is a longitudinal cross-sectional view of a composite distribution and transmission line, post or suspension insulator of the present technology; FIG.

[0035] [Figure 2] FIG. 2 is a partial longitudinal cross-sectional view of the composite insulator of FIG. 1.

[0036] [Figure 3] FIG. 10 is a close-up view of the lip showing various angles and radii.

[0037] [Figure 4] FIG. 2 is a partial longitudinal cross-sectional view of a fuse cutout.

[0038] [Figure 5] FIG. 2 is a longitudinal cross-sectional view of the bushing. DETAILED DESCRIPTION OF THE INVENTION

[0039] Unless expressly stated otherwise, the following rules of interpretation apply to this specification (description of the invention and claims): (a) all words used herein shall be construed according to their gender or number (singular or plural) as the context requires; (b) the singular terms "a," "an," and "the," as used in the specification and the appended claims, include plural references unless the context clearly dictates otherwise; (c) the antecedent term "about," applied to a stated range or numerical value, indicates an approximation within the deviation of that range or numerical value known or expected in the art from the method of measurement; (d) "herein," "hereby," "of," "toward," "earlier," "hereafter," and words of similar import, unless otherwise specified, refer to this specification as a whole and not to any particular paragraph, claim, or other division; (e) descriptive headings are for convenience only and do not control or affect the meaning or construction of any portion of this specification. and (f) "or" and "any" are not exclusive, and "include" and "including" are not limiting. Further, the terms "comprising," "having," "including," and "containing" are to be construed as open-ended terms (i.e., meaning "including, but not limited to") unless otherwise expressly stated.

[0040] The recitation of ranges of values ​​herein is intended only as a shorthand method for individually referring to each individual value within that range, and each individual value is incorporated herein as if it were individually set forth herein, unless otherwise specified herein.When a specific range of values ​​is provided, unless the context clearly dictates otherwise, it is understood that the upper and lower limits of that range, and any other stated or intervening values ​​within that stated range, are included in that range to the nearest tenth of the lower limit.All smaller subranges are also included.The upper and lower limits of these smaller ranges are also included in that range, subject to any specifically excluded limits within that stated range.

[0041] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art. Although methods and materials similar or equivalent to those described herein can also be used, acceptable methods and materials are now described. definition

[0042] Bushing - In the context of the present technology, a bushing is an insulator with a conductive core rod.

[0043] Fuse cutout - In the context of the present technology, a fuse cutout is a fuse holder that includes at least one insulator.

[0044] Insulators - In the context of the present technology, insulators include bushings, fuse cutout insulators, distribution and transmission line insulators, post insulators, and suspension insulators.

[0045] Drip Bead - In the context of the present technology, a drip bead is present around the periphery of the shed and is shaped to cause moisture to form droplets that are released from the drip bead, thus reducing or eliminating the problem of moisture and contamination of the insulation. The drip bead also acts as a rain screen.

[0046] Downward - In the context of the present technology, "downward" is defined with respect to the top and bottom surfaces of the shed, which extend outward towards the periphery. The top surface has a downward slope from the rod, as can be seen in Figure 1.

[0047] As shown in FIG. 1, a composite distribution and transmission line, post, or suspension insulator, generally designated 6, has a rod 8 with a bore 10 therethrough. Extending outward from the rod 8 are a series of sheds, collectively designated 14. The sheds 14 are continuous with the rod 8; in other words, the two are of one piece, and may be injection molded. There is a smaller diameter shed 16 and a larger diameter shed 18. The larger diameter shed 18 extends outward beyond the perimeter 20 of the smaller diameter shed 16. The larger diameter shed 18 terminates in a peripheral lip 22 that extends downward from the underside of the shed 18 (the upper surface of the shed slopes downward from the rod 8). The peripheral lip 22 functions as a rain screen or drip bead, allowing water and contaminants to drain away. This minimizes the hydrophobic effects of the surface material. This also reduces or eliminates the attachment of proteins and droplet-borne algae that can promote algae growth on surfaces.

[0048] 2, rod 8 comprises a core rod 30, preferably fiberglass or fiberglass reinforced polymer, and a housing 32, preferably silicone rubber, that encases core rod 30. Shed 14 is preferably silicone rubber. Each end has a fitting 34.

[0049] The peripheral lip 22 is shown in detail in FIG.

[0050] In one embodiment, in use, the composite insulator 6 is attached at one end to a distribution or transmission line (power line) support and at the other end to the power line, with its orientation being essentially vertical for power line and post insulators and essentially horizontal for suspension insulators. The power line support may be a metal tower, a wooden pole, or a composite pole. The substantially vertical orientation allows larger diameter sheds to direct one or more of rain, sea spray, lake spray, road deicer brine, pollutants, nutrients, and algae away from smaller diameter sheds and also reduces the flow of water under larger diameter sheds with a peripheral lip.

[0051] In another embodiment, in use, the composite insulator 6 is attached at one end to a distribution line support and at the other end to the distribution line, with the orientation being essentially vertical. The distribution line support may be a metal, composite, or wooden pole. The substantially vertical orientation allows the larger diameter shed to direct one or more of rain, sea spray, lake spray, road deicer brine, pollutants, nutrients, and algae away from the smaller diameter shed, and also reduces the flow of water under the larger diameter shed with a peripheral lip. The composite insulator is preferably a suspension insulator.

[0052] Another embodiment shown in FIG. 4 is a fuse cutout generally designated 100. The fuse cutout 100 includes at least one insulator 6. The insulator 6 includes a rod 8 with a bore 10 therethrough. The fuse cutout 100 further includes a fuse holder 102 containing a replaceable fuse 104 and a base 106. Extending outward from the rod 8 are a series of sheds 14, one or more of which include a perimeter lip 22. There are smaller diameter sheds 16 and larger diameter sheds 18. The larger diameter sheds 18 extend outward beyond the perimeter 20 of the smaller diameter sheds 16. The larger diameter sheds 18 terminate at the perimeter lip 22, which is shown in more detail in FIG. 3. The perimeter lip 22 functions as a rain screen or drip bead to allow water and contaminants to drain away. This allows the hydrophobic effect of the surface material to be minimized, which also reduces or eliminates the adhesion of proteins and droplet-borne algae that can promote algal growth on the surface.

[0053] 2, rod 8 includes a core rod 30, preferably fiberglass or fiberglass reinforced polymer, and a housing 32, preferably silicone rubber, that encases core rod 30. Shed 14 is preferably silicone rubber.

[0054] Another embodiment shown in FIG. 5 is a bushing generally designated 200. The bushing 200 includes a rod 8 with a bore 12 extending therethrough and a core rod 30, which is an electrical conductor. An insulating layer 202 is located within the bore 12 between the inner surface 204 of the rod 8 and the inner core rod 30. The insulating layer may be mineral oil or a hardening epoxy resin. The bushing 200 further includes a gasket 206 at the transformer end and a terminal 208 at the end opposite the transformer end. Extending outward from the rod 8 are a series of sheds 14, one or more of which include a peripheral lip 22. The larger diameter sheds 18 extend outward beyond the outer periphery 20 of the smaller diameter sheds 16. The larger diameter sheds 18 terminate at the peripheral lip 22, which is shown in detail in FIG. 3. The peripheral lip 22 functions as a rain screen or drip bead to allow water and contaminants to drain away. This allows the hydrophobic effect of the surface material to be minimized, which also reduces or eliminates the adhesion of proteins and droplet-borne algae that can promote algal growth on the surface.

[0055] In yet another embodiment, the rain guard or drip bead is formed as a downwardly extending perimeter wedge.

[0056] In yet another embodiment, each smaller diameter shed 16 also has a rain guard or drip bead as a lip or wedge.

[0057] In yet another embodiment, the sheds are all the same diameter.

[0058] In yet another embodiment, all sheds have a rain screen or drip bead.

[0059] To manufacture a rod and a series of sheds, at least one of which has a downwardly extending peripheral drip bead, a mold for the rod and the series of sheds is provided, a composite material is injected into the mold, and the combined rod and series of sheds is then removed from the mold.

[0060] While exemplary embodiments have been described in terms of what are presently considered to be the most practical and / or suitable embodiments, it should be understood that the description is not limited to the disclosed embodiments, but rather is intended to cover various modifications and equivalent arrangements included within the spirit and scope of the exemplary embodiments. Those skilled in the art will recognize, or be able to ascertain using no more than routine experimentation, numerous equivalents to the specific exemplary embodiments specifically described herein. Such equivalents are intended to be encompassed by the claims, whether appended hereto or subsequently filed.

Claims

1. 1. An insulator for use in electrical power transmission and distribution, the insulator comprising: a rod including an interior surface defining a bore; a core rod received within the bore; and a plurality of sheds contiguous with and extending outwardly from the rod, at least one shed including a downwardly extending circumferential drip bead. An insulator comprising:

2. 2. The insulator of claim 1, wherein at least one shed has a smaller diameter and at least one shed has a larger diameter, and the at least one shed having the larger diameter includes the downwardly extending circumferential drip bead.

3. 3. The insulator of claim 2, wherein there is a series of sheds, said series of sheds alternating between said sheds having said larger diameter and said sheds having said smaller diameter.

4. 4. The insulator of claim 3, wherein both the shed having the larger diameter and the shed having the smaller diameter include a downwardly extending circumferential drip bead.

5. The insulator of any one of claims 2 to 4, wherein the downwardly extending circumferential drip bead is a lip.

6. The insulator of any one of claims 2 to 4, wherein the downwardly extending circumferential drip bead is a wedge.

7. The insulator according to any one of claims 1 to 6, further comprising a housing that covers the core rod.

8. The insulator of claim 7 wherein the housing and the shed comprise silicone.

9. 9. The insulator of claim 7 or 8, wherein the core rod comprises a glass fiber reinforced polymer.

10. The insulator of any one of claims 1 to 9, wherein the insulator is a suspension insulator.

11. The insulation of any one of claims 1 to 9, wherein the insulation is a line insulation.

12. The insulator of any one of claims 1 to 9, wherein the insulator is a post insulator.

13. The insulator of any preceding claim, wherein the insulator is configured for use in a fuse cutout.

14. The insulator according to any one of claims 1 to 4, wherein the core rod is a conductive rod.

15. The insulator of claim 13 further comprising an insulating layer within the bore between the core rod and the inner surface of the rod.

16. 16. The insulator of claim 14 or 15, wherein the insulator is a bushing.

17. The insulator of any preceding claim, wherein the rods and sheds comprise a composite material.

18. 20. The insulator of claim 17, wherein the rod and the shed are injection molded.

19. A method for manufacturing a one-piece article for use in an insulator, the one-piece article comprising a rod and a series of sheds, at least one of the sheds including a downwardly extending peripheral drip bead, the method comprising the steps of: providing a mold; injecting a composite material into the mold; and removing the rod and the series of sheds as a one-piece article from the mold.

20. 1. A method for reducing algae growth on composite insulators, the method comprising: selecting a composite insulator comprising: a rod including a core rod and a housing covering the core rod; and a plurality of sheds, at least one shed having a smaller diameter and at least one shed having a larger diameter and positioned over the shed with the smaller diameter, the shed with the larger diameter including a peripheral lip; and attaching the composite insulator to both an electric power transmission line and a transmission line support, or to both an electric power distribution line and a distribution line support.

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