Abstract:
An adjustable cover for outdoor electrical substations is disclosed. The traditional metal cover for these installations is capped with length adjustable fiberglass reinforced plastic cover pieces. The cover pieces slide over one another in an interlocking relationship to accommodate the top surfaces of a variety of existing electrical substations. Once in place the covers are maintained in the same interlocking plane to the top surface of the substation with their cooperating flanges insuring positive prevention of weather related water damage to sensitive electrical components. End caps further enhance the degree of water damage protection.

Description:
BACKGROUND 
     This invention relates to covers for electrical substations, and in particular to covers for existing electrical substations to prevent weather related damage to components of these substations. 
     Electrical power transmission comprises a variety of systems for transmitting power from one facility to another. Various functions include switching stations, step down transformers, and so on. Equipment contained in these substations includes circuit breakers, devices for switching equipment in and out of service, lightning arrestors, and sophisticated abnormality control systems. Frequently the most practical or only location for electrical substations is the outdoors. One of the most important factors in electrical reliability then becomes the elimination of water from penetrating into these outdoor facilities. 
     Many attempts have been made, of course, to overcome the effects of weather on sensitive electrical and electronic components to be located outdoors, For example, in U.S. Pat. No. 2,952,799, issued Sep. 13, 1960, an outdoor metal clad switchgear structure is disclosed. In this structure, a basic unit  10  (FIG. 1) encloses a circuit breaker cell  13 . An enclosed service isle  11  (FIG. 13) provides protection for maintenance personnel from the weather while servicing the equipment, and access to electrical components, such as a circuit breaker, is provided without exposure of the components to the outdoor weather. Again, in U.S. Pat. No. 3,723,824, issued Mar. 27, 1973, a telescoping outdoor switchgear assemblage is described. This patent teaches “the switch gear is so constructed that the aisle section and switchboard section may be telescoped over one another during shipment, thereby to reduce volume and shipping costs while simplifying erection in the field.”, col. 1, lines 33-38. U.S. Pat. No. 4,327,530, issued May 4, 1982, discloses an enclosure for weatherproofing electrical equipment such as outside plant telephone electronics. In this invention a mushroom shaped hood  11  (FIG. 1) is supported by a spring-driven lifting mechanism  12  which automatically raises the hood above the level of the enclosed electronic equipment when the lifting mechanism is unlatched. In U.S. Pat. No. 5,136,463, issued Aug. 4, 1992, a universal enclosure for housing outside plant equipment in order to protect the equipment from harmful weather effects is disclosed. An electrical panel mounted internally of the universal enclosure, but accessible from the exterior of the universal enclosure, facilitates servicing the equipment while maintaining craft separation. U.S. Pat. No. 5,435,641, issued Jul. 25, 1995, teaches a cabinet  1  (FIG. 1) having a unitary or monobloc body of pressed construction, such a glass fiber-reinforced polyester, to protect electrical equipment exposed to the weather. 
     While the above noted inventions provide useful devices and methods for protecting various electrical systems from weather related harmful effects, they do not envision the adjustable cover for pre-existing electrical substations of the present invention. 
     It is therefore a primary object of the present invention to provide a protective cover for outdoor electrical substations. 
     An additional object of the invention is to provide a linear adjustable, telescoping cover for protecting pre-existing outdoor bus ducts from weather related deleterious effects. 
     A further object of the invention is to provide a telescoping construction to eliminate any type of seam on the horizontal or vertical by the use of overlapping flanges at each end of the weather protective cover. 
     Still another object of the invention is to provide an adjustable, weather resistant fiber glass reinforced plastic cover for pre-existing electrical substations. 
     Yet another object of the invention is to provide a weather protective cover to accommodate virtually all designs of 13 kV bus ducts. 
     An additional object of the invention is to provide a weather protective cover to accommodate virtually all designs of 4 kV class “C” switchgear. 
     SUMMARY 
     These and other objects are obtained with the adjustable cover for electrical substations of the present invention. 
     Typically, when protecting outdoor positioned electrical equipment from weather related damage metal enclosures of various types are employed. Over time rain and snow deposited water will often find its destructive way into sensitive electrical substation components. Causes for these structural failures range from outright corrosion of the metal closure to pin hole leaks developing at welded junctures. These water leaks are a constant source of electrical failure problems, necessitating frequent maintenance and repair procedures. Attempts at repair, including re-welding leaking joints, or re-caulking these joints are often, at best, a temporary correction for the problem. 
     It occurred that placing a suitable adjustable cover structured to be free of potential areas for weather leakage over outdoor located electrical substations would significantly improve reliability of these electrical transmitting stations while lowering the necessity for frequent inspections. Instead of using corrosion prone metal as a cover, a fiberglass reinforced plastic, such as fiberglass reinforced polyester, was selected as the material of fabrication for the covers. To further aid longevity of the covers a UV resistant gel coat, such as ANSI-61, can be applied to their exterior surfaces. Electrical substations such as, for example, 13 kV bus ducts or 4 kV class “C” switchgear, often have similar shapes including extended length in relation to width, making possible a relatively small number of adjustable covers for a wide range of substations. A main cover piece can measure, for example, approximately 11½′ by approximately 14″ in height. The cover has a generally, slightly gabled cover top surface, and downwardly projecting left and right side walls, defining a C shaped opening at both ends of the cover. An approximate 2″ wide flange extends downwardly from the top surface, and inwardly from each side, at each end of the cover. A similar 2″ wide flange extends outwardly at the base of the left and right side walls. To further aid water run off, the cover top surface section gently slopes to the left and right along its center line running the length of the cover. A pair of support bars, each bar being placed a spaced distance from each end of the main cover, further aids the utility of the cover. The support bars for covers for existing substation designs measure approximately 5″ in height and are connected to each end of the bar at the sides of the cover. The purpose of the support bars is to provide structural support for the cover; and to permit clearance of protrusions extending above the top surface of the electrical substation being covered. These insure resistance to wind forces and provide easy positioning on the top surface of the substation irrespective of these protrusions. 
     The above described main cover piece can be used as an effective water shedding cover by itself. For example, this cover can be placed, either with or without cover end caps, on suitable bus ducts, and secured to the ducts utilizing straps, such as “POLYSTRAPS” or “POLY-CORDS” which are well known to the trade. However, the utility of this weather protecting method is further enhanced with the use of an extender cover piece. This extender piece is similarly constructed to the main cover piece, being, for example, approximately 7′ in length and 32″ in width, with C shaped ends designed to interlock with the C shaped ends of the main cover piece. The extender piece has an upraised flange-along the top and sides of at least one end so as to interlock with the downwardly and inwardly projecting flange on each end of the main cover piece. When interjoined, the cover system of the invention provides a length adjustable overlapping design which eliminates any sealing rings, caulking, welding, or bolted connections which are susceptible to water intrusion. 
     To use the covers of the present invention they are simply placed on the top of existing equipment, and strapped to the bottom of the equipment using the aforementioned “POLYSTRAPS” or “POLY-CORDS”. The installation does not require special tools or devices making set up extremely fast and easy. When two or more covers are employed the overlapping construction simply requires sliding units back and forth on each other for the design to fit. The system is designed to cover all hatches on the electrical substation roof sections and all joining assemblies when the substation is bolted together. All welded seams of the substation are covered, including along the top of the station where the sides meet the horizontal flat roof. 
     Thus it can be seen the electrical substation cover of the present invention provides a unique, new method for preventing water, snow, or ice from penetrating sensitive electrical equipment, resulting in the extension of the life of the original equipment, the prevention of costly failures and power outages, and the significant reduction in maintenance costs. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS 
     FIG. 1 is a partially broken away schematic, perspective representation of one version of the adjustable cover of the invention shown in place covering an electrical substation. 
     FIG. 2 is a perspective view of one version of the main cover piece of the invention with internal support bars shown in dotted lines. 
     FIG. 3 is a perspective view of a first version of the extender cover piece of the invention with internal support bars shown in dotted lines. 
     FIG. 4 is a perspective view of one version of the main cover piece of the invention shown with an end cap secured in place. 
     FIG. 5 is a schematic representation on one version of an end cap for the main cover piece of the invention. 
     FIG. 6 is a perspective view of a second version of the extender cover piece of the invention with internal support bars shown in dotted lines. 
    
    
     DETAILED DESCRIPTION 
     Turning now to the drawings wherein similar structures having the same function are denoted with the same numerals, in FIG. 1 a perspective view of one complete version of the invention  10  is shown. An electrical substation  16  such as, for example, a 13 kV bus duct or a 4 kV class “C” switchgear, is shown as having its top surface and parts of each side being covered by a main cover piece  12 , and an interlocked, first version extender cover piece  14 . The main cover piece  12  and the extender cover piece  14  are shown secured to an electrical substation  16  by means of straps  15  such as “POLYSTRAPS” or “POLY-CORDS”. Typical structural components of a substation which protrude above the normally level top surface of the substation, such as a metal box  18 , or a welded metal flange having a top section  19  and a side section  20  joining two sections of the substation together, are compensated for by support bars  22  (denoted in dotted lines) affixed within both the main cover piece  12  and the extender cover piece  14 . These support bars are connected to and positioned perpendicular to the sides of each cover piece, typically adjacent each end of each cover piece. When the extender cover is in position, the lower surface of the support bars is positioned on the top surface of the substation. In addition to strengthening the cover pieces for handling and for resisting torsional forces due to wind at a site, the respective height of these support bars is selected to insure that the cover pieces are maintained substantially parallel to the plane of the top surface of the substation so that higher structural obtrusions on the top surface of a substation e.g.,  18  or  19 , do not tilt one or more cover pieces in a manner that would permit the entrance of water within the cover pieces. 
     The structure and interlocking relationship of the adjustable covers of the invention are best seen in FIGS. 2 and 3. In FIG. 2 a main cover piece  12  is shown having a top surface  12 A, and left and right sides  12 B. Each end of the main cover is defined by a C shaped opening  25  bound by the top and two sides. The top surface  12 A of the main cover piece slopes gradually to the left and right from a center line  13  extending along the length of the top surface. At each end of the main cover piece there is an inwardly extending flange  24  positioned perpendicular to the top surface  12 A which is confluent with inwardly extending flanges  26  positioned perpendicular to the sides  12 B of the main cover piece. A side flange  28  extends outwardly from the base of each side  12 B of the main cover piece, extending the full length of the main cover  12 . This side flange has a slight pitch downward so as to facilitate water runoff away from the substation At least two support bars  22  are shown affixed to the sides  12 B of the main cover, positioned perpendicular thereto. 
     In FIG. 3 a first version of an extender cover piece  14  is shown having a generally C-shaped structure similar to that of the main cover piece. However, at least at a first end of the extender piece there is a flange  30  extending outwardly from and perpendicular to the top surface  14 A of the extender piece; and, an outwardly extending flange  32  perpendicular to the sides  14 B of the extender piece confluent with flange  30 . Again as in the case with the main cover piece at least a pair of support bars  22  are affixed to the sides, positioned perpendicular to the sides and adjacent typically near each end of the extender piece. The other end of the extender cover piece  14  is shown with a similar flange construction to facilitate joinder with an additional main cover such as  12 , if desired. 
     A side flange  33  extends outwardly, also with a slight pitch downward, from the base of each side  14 B and can extend the full length of the extender cover  14  except where a possible interference problem exists with the main cover side flanges,  26  (see the discussion below related to FIG.  6 ). 
     The dimensions of a main cover piece for installation, for example, on a 13 kV outdoor bus duct, can be approximately 11′8″ in length, 37′ in width, and 14″ in height. The dimensions for an extender cover piece for this same application can be approximately 6′9″ in length, 32″ in width, and 12″ in height. In both cases the covers would be molded in seamless fiberglass reinforced plastic, such as polyester, with an ultraviolet inhibitor such as ANSI-61 gel coat. 
     To use the adjustable covers of the invention a main cover piece  12  can be used by itself by simply having an operator place it on the top surface of the electrical substation, securing it in place by means of suitable straps. A pair of end caps (see FIG. 5) would be employed to seal each end. 
     Where additional length is required an extender cover piece  14  is interlocked beneath the main cover piece on the top surface of the substation. The inwardly directed flanges  24 ,  26  at the interlocking end of the cover piece overlap and cooperate with the outwardly directed flanges  30 ,  32  of the top surface  14 A and of the sides  14 B of the extender cover piece. The height of the support bars  22  in each of the cover pieces, is selected to insure respective protrusions are avoided and that the flanges on each cover piece do overlap. In this manner water from the elements is positively prevented from entering into the substation and thereby damaging sensitive components. 
     As shown in FIGS. 4 and 5 an end cap  34  is employed to further prevent any water from gaining entrance to the electrical substation at the free end of each cover piece not interlocked with the other. To prevent water damage at this point a fiberglass reinforced plastic end cap  34  is fabricated having a free end similar to that of the extender cover piece  14 , with an outwardly extending flange  34 A at a top surface of the cap, and a confluent outwardly extending flange  34 B at both sides of the generally C shaped opening of the cap. In use the cap would simply slip within the top and side flanges  24 ,  26  of the main cover. The end cap can have a support bar  22  similar to that of the extender piece  14 , but having a closed second end  35  in contrast to the open ended structure of the extender piece. 
     A second version of a possible end cap is shown in FIG.  3 . This cap  36  is designed to form a sealed enclosure with an extender piece  14 . In this case inwardly extending flanges  36 A extending perpendicularly from a generally C shaped first opening are confluent with flanges  36 B extending inwardly from the sides of the cap. Similar to end cap  34 , this end cap  36  can have a support bar  22  and a closed second end  37 . In use this second version cap  36  would slip over the top and side flanges  30 ,  32  of the extender piece  14 . Obviously a variety of other means can be utilized for closing off the free end of the main or extender cover piece, as, for example bolting a cover onto the flanges at the exposed end, extending the length of the flanges themselves to seal off the open area, and so on. 
     FIG. 6 illustrates a second version  14 C of the extender cover piece  14  depicted in FIG.  3 . When the configuration of the particular electrical substation to be covered is known in advance, and therefore its overall dimensions including length, so that large scale adjustments of cover piece length will not be required, the extender cover piece can include modified side flanges  33 B. The flanges  33 B begin a spaced distance  33 A away from the base of the extender piece outwardly extending side flange  32  at the C shaped openings, at both ends of the extender piece  14 C. This permits some lateral adjustment when the main cover piece  12  is placed over the modified second version extender cover piece  14 C. 
     Thus it can be seen that a significant new weather protecting cover system can be supplied for new or pre-existing electrical substations. The covers are installed quickly and reliably without utilizing special tools or techniques. The interlocking, adjustable method of the invention provides for installation of these length adjustable covers over a wide variety of existing electrical substations. Once in place, water is effectively eliminated from entering electrical substations providing significant performance enhancement while at the same time greatly reducing maintenance and inspection requirements. 
     While the particular design shown , in certain of its specifics, is directed to the assignee&#39;s 13 kV bus duct systems, different shapes and sizes will accommodate various similar equipment, e.g. assignee&#39;s 4 kV class “C” equipment, and others, and still be within the spirit and scope of the present invention as set forth in the following claims.