POWER TRANSMISSION SHIELD
RELATED APPLICATIONS
This application claims priority to U.S. provisional application serial number 60/333,870, filed November 28, 2001, entitled "POWER TRANSMISSION SHIELD FOR BIRDS" and which is incorporated herein by reference.
BACKGROUND
In the enterprise of power transmission, there are numerous locations where a large potential difference in voltage is realized. For example, electrical transmission lines and power transformers are often positioned upon vertical support structures such as power transmission poles or towers. Birds, including birds of prey or raptors, often perch and land upon power transmission poles and attached cross members that support the transmission lines such that they have a vantage point from which to look for prey. Although insulators are provided where the transmission lines rest on the cross members, if these birds touch either the transmission lines, the transformer lines extending from the transmission lines to the transformer connectors, or the transformer connectors themselves when such birds are also touching the pole structure, such as when a bird spreads its wings to take off or jump from the pole to the line, the current on the line will electrocute the bird and cause a short circuit damaging the electrical transmission components. As a number of raptors are considered endangered species, there is an acute need to prevent such an occurrence from happening.
Current insulating solutions around power transmission structures do not provide a reliable, durable, weatherproof, lightweight, low cost, and highly insulative product that is easy to install on a wide range of structures having varying geometries and configurations, such as transmission lines and transformer connectors.
SUMMARY
The present invention provides a power transmission shield to prevent animals from electrocution around certain structures. The shield may include an insulative mesh structure formed of a plurality of fibrous strands and an attachment means to secure the insulative mesh structure to a current carrying device. In one aspect, the
insulative mesh is an elongate wrap that can be rolled around a current carrying object to provide at least one insulative layer on objects of varying geometries (e.g., cylindrical or irregular geometries). In another aspect, the insulative mesh structure may be either a woven or unwoven structure that is air and water permeable, and may be made of plastic. In yet another aspect, the insulative mesh structure should have a sufficiently thick material matrix to ensure that an animal contacting a surface of the mesh structure will not have transmission current conducted thereto by the current carrying device. In a further aspect, the power transmission shield can be used in conjunction with the rotatable objects, or spinners, and wheels to provide a structure to cover all the power transmission components near the power transmission support structures and substations.
BRIEF DESCRIPTION OF THE DRAWINGS
Fig. 1 shows a perspective view of one power transmission shield; Fig. 2 shows a close-up view of the power transmission shield of Fig. 1 showing an insulative mesh structure;
Fig. 3 shows a rotatable spinner, wheel and clamp;
Fig. 4A shows the rotatable spinner of Fig. 3 modified to fit onto a transformer connector to form another power transmission shield; Fig. 4B shows the insulative mesh structure of Fig. 1 positioned on the transformer connector to form another power transmission shield; Fig. 4C shows a collar formed of the insulative mesh structure of Fig. 1 positioned on the transformer connector to form another power transmission shield;
Fig. 5 shows a side elevational view of the transmission line and an insulator guard with a set of rotatable spinners and wheels mounted thereon to form another power transmission shield;
Fig. 6 shows a front elevational view of the power transmission shield of Fig. 5;
Fig. 7A shows a top plan view of another power transmission shield; Fig. 7B is a front elevational view of the power transmission shield of Fig. 7A; Fig. 8A shows a top plan view of another power transmission shield; Fig. 8B is a front elevational view of the power transmission shield of Fig. 8A.
DETAILED DESCRIPTION OF THE INVENTION
A power transmission shield 10 is shown generally in Fig. 1. The power transmission shield 10 includes an insulative mesh structure 12 formed of a plurality of fibrous strands 14, as best seen in Fig. 2, and an attachment means 16 to secure the insulative mesh structure 12 to a current carrying device, such as a transmission line 100.
The insulative mesh structure 12 is formed in such a way that the fibrous strands 14 overlap each other in three-dimensional space. Ideally, the fibrous strands 14 are woven together, but could be unwoven if the strands are strong enough and are sufficiently tangled together such that the friction between the strands provides good tensile strength to the insulative mesh structure 12, and the strands do not easily degrade with use. For example, the fibrous strands 14 may be made of a plastic or other polymer, such as plastics of the polymer resin or cellulose derivative types, or other type of plastic. However, the fibrous strands 14 may also be made of another synthetic material that provides physical properties similar to plastics. Also, for any section of the insulative mesh structure 12 desired to be used on a current carrying device, the mesh structure 12 may have a pair side edges 18, a lead edge 20 and a tail edge 22, which may be woven or otherwise formed to have a defined boundary.
Because free space is formed between the fibrous strands 14, as seen in Fig. 2, the insulative mesh structure 12 is highly air and water permeable (i.e., drainable) and therefore is substantially resistant mold or rot, and avoids freeze and thaw cycles that cause cracking in solid insulative bodies. Additionally, these physical properties of the insulative mesh structure 12 prevent it from leading to the decay of an underlying protected structure (e.g., transmission line 100) and allows heat to escape structures from current carrying devices such as lines, transformers, and other surfaces. The insulative mesh structure 12 is preferably provided as a "wrap", or an elongate sheet 24 that can be wound on a roll for storage and cut to any length in the field, but may also be pre-molded or stitched to fit any application, such as a collar 26 for a transformer 200 to cover a transformer connector 202, as shown in Fig. 4C. Ideally, the insulative mesh structure 12 has the following properties: ultraviolet light (UN) resistant, durable and wear resistant, heat resistant, highly insulative (high dielectric), chemically unreactive, light weight, insensitive to temperature fluctuations, low static
carrying, low wind resistant. These properties make the power transmission shield 10 low maintenance, such that utility workers do not have to frequent the location of the shield for maintenance thereof.
The thickness of the insulative mesh structure 12, and number of layers thereof to be applied to an underlying current carrying device, will depend on a number of factors, including the magnitude of the voltage of the current carrying device, the density of the fibrous strands 14 in the mesh structure, the weather conditions in the area of application, among other factors. Preferably, the insulative mesh structure 12 has a thickness sufficient to support the weight of a animal, specifically a bird, without folding or collapsing, while attenuating the risk of electrical shock to the animal. A thickness of about 1/8 of an inch or more for the insulative mesh structure 12 is preferred. The insulative mesh structure 12 should be strong enough to withstand the pressure applied thereto by the claws of a bird grasping at the current carrying device (e.g., transmission line 18) below the structure. Also, the insulative mesh structure 12 is designed to have some amount of elasticity, such that it can stretch and conform to cover current carrying devices of varying geometries.
Various attachment means 16 may be used to secure the insulative mesh structure 12 to a current carrying device. In Fig. 2, a tie strap 28 is extended around the circumference of the insulative mesh structure 12 and underlying transmission line 100 to secure the mesh structure to the line. However, other means, such as clips, brackets, set screws, clamps, adhesives, etc., may be used to secure the insulative mesh structure 12 to a current carrying device. For example, a plate with at least one hook (not shown) may be placed over the insulative mesh structure 12 and the hook inserted into at least two layers of the mesh structure near the lead edge 20 to secure the free end of the mesh structure to the underlying layers. An adhesive could also be applied to the lead edge 20 of the insulative mesh structure 12 once the mesh structure was wrapped around a current carrying device to secure the lead edge 20 to an underlying layer of the mesh structure. The attachment means 16 allows for placement of the insulative mesh structure onto horizontal or vertical structures, as well as structures of other configurations, as shown in Figs. 8A and 8B for the transmission lines 100.
Fig. 3 shows a set of objects that can be used in conjunction with the power transmission shield 10 to prevent animals from being electrocuted by current carrying devices, and incorporating the teachings of U.S. Patent Application Serial Number 10/196,021, filed July 16, 2002, which has the same inventors as the present application. A rotatable element, or roller 30, preferably has a hollow core 31 and a hole 32 formed at opposing longitudinal tapering ends 34 thereof, the holes 32 being configured to surround a generally cylindrically shaped line, such as transmission line 100, for rotation thereabout. The rotation of the roller 30 prevents an animal from resting thereon or attempting to travel along the length of the transmission line 100, putting the animal farther away from location whether they may ground while touching a current carrying device and be electrocuted. The roller 30 may be bifurcated longitudinally into two generally equal portions for placement around the transmission line 100. An end shield, or wheel 36, has a hub 38 defining a hole 40. The hole 40 may be sized for fitting onto one tapering end 34 of the roller 30, or for generally surrounding the transmission line 100 alone or surrounding the transmission line 100 with the insulative mesh structure 12 installed thereon. Radially extending spokes 42 extend from the hub 38 to support a series of concentric outer rings 44. A radial slot 46 extends along one of the spokes 42 so that the wheel 36 may be slipped over the transmission line 100 for installation. As shown in Figs. 5 and 6, the wheel 36 serves as another barrier to animals landing on, or traveling along, the transmission line 100, and may be secured to another wheel 36, as seen in detail in Fig. 5, to shield an insulator 300 and reduce the risk of animal electrocution. A clamp 48 may also be provided, and may be secured to a transmission line 100 by a tying means, such as tie strap 28, or any other means, such as a set screw. The clamp 48 ensures that a series of rollers 30 and/or wheels 36 remain properly positioned on the transmission line 100 and do not separate longitudinally along the transmission line, as shown in Fig. 5. Each of the roller 30, the wheel 36, and the clamp 48 may be made of UN resistant injection molded plastic, for example.
Figs. 4A and 4B show various usages of the rollers 30 and insulative mesh structure 12 in conjunction with one transformer 200. Each roller 30 may be sectioned transversely to expose the hollow core 31 so that the roller 30 may be placed over one of the transformer connector 202 and secured to a housing 204 of the
transformer 200. The insulative mesh structure 12 may also be wrapped around and over a top surface of one of the transformer connectors 202 in the same fashion as described herein for wrapping the mesh structure around a transmission line 100. Both the sectioned rollers 30 and insulative mesh structure 12 insulate the transformer from discharging a current to an animal that may land on, or travel across, the transformer connectors 202 and along connected transmission lines 100. Also, with the usage of the rollers 30 and insulative mesh structure 12 on the transformer connectors 202, a passageway or hole must be formed in the rollers 30 or insulative mesh structure 12 such that a transformer line 206 can extend from the respective transformer connector 202 to the transmission lines 100 atop a power pole 208 or tower, as seen in Figs. 7 and 8.
Figs. 7A and 7B show the rollers 30, wheels 36 and clamps 48 used to impede an animal from contacting a current carrying device while such animal may be grounded. Fig. 7A illustrates how the rollers 30, wheels 36 and clamp 48 may be positioned upon transmission lines 100. Fig. 7B illustrates one set of transformer lines 206 covered by the rollers 30; however, all exposed transformer lines 206 would ideally be covered by such rollers 30. For example, when a bird perches atop a cross member 210 of the power pole 208, its wings would substantially only touch the rollers 30 or the wheels 36, instead of the transmission lines 100 or insulators 300 of Fig. 7 A, or the transformer lines 206 or transformer connectors 202 of Fig. 7B. Figs. 8A and 8B show the insulative mesh structure 12 used in a manner similar to the rollers 30, wheels 36 and clamps 48 of Figs. 7A and 7B, to impede an animal from contacting a current carrying device while such animal may be grounded. Fig. 8A illustrates how the insulative mesh structure 12 may be positioned upon transmission lines 100. Fig. 8B illustrates the transformer lines 206 covered by the insulative mesh structure 12. By example, when a bird perches atop the cross member 210 of the power pole 208, its wings would substantially only touch the insulative mesh structure 12, instead of the transmission lines 100 or insulators 300 of Fig. 8A, or the transformer lines 206 or transformer connectors 202 of Fig. 8B. It is to be understood that the power transmission shield can be used to cover many different exposed current carrying devices or parts thereof that would create electrical shock, and not merely structures atop power transmission poles or towers.
For example, transformers and transmission lines at power substations can be equipped with the power transmission shield.
Since certain changes may be made in the above shield and methods of use without departing from the scope hereof, it is intended that all matter contained in the above description or shown in the accompanying drawing be interpreted as illustrative and not in a limiting sense. It is also to be understood that the following claims are to cover certain generic and specific features described herein.