DESC:POWER DISTRIBUTION UNIT

CROSS-REFERENCE TO RELATED APPLICATIONS

[0001] This application claims the benefit of Indian Provisional Application No. 2517/MUM/2013, filed on January. 30, 2014. The entire disclosure of the above application is incorporated herein by reference.

FIELD OF THE INVENTION

[0002] The invention relates to a power distribution unit and more particularly to power distribution unit for installation in an underground electrical supply system.

BACKGROUND OF THE INVENTION

[0003] Generally, power distribution is done through feeder pillar systems. Feeder pillar systems comprise an enclosure that includes switches, links and fuses, for connecting a feeder cable of a power distribution system with multiple distribution cables.

[0004] The enclosure of a feeder pillar system includes a door for providing access. The enclosure is exposed to environmental conditions at all times and thus over a period of time gets corroded. Also these enclosures are not water-proof. Hence moisture and water make way into the enclosure resulting in flashovers and short circuiting, which is undesirable.

[0005] Further, the door of the enclosure provides easy access making the power distribution system vulnerable for power and component theft.
[0006] Another disadvantage includes requirement of space for installation of feeder pillar systems as the feeder pillar systems are typically located outdoors on pavements. This causes inconvenience to pedestrians using the pavement.

[0007] During a faulty condition in the feeder pillar system, faulty cables are removed to avoid short circuits and flashovers, which results in interruption of power supply to individual consumers.

[0008] In view of the above, there is a need for a power distribution unit addressing at-least the above mentioned problems and/or other problems related to power distribution.

SUMMARY OF THE INVENTION

[0009] In one embodiment, a power distribution unit is provided. The power distribution unit includes a housing assembly comprising a housing, at least one bus bar assembly provided in the housing, the bus bar assembly allowing a plurality of distribution cables to be connected to a plurality of feeder cables, the bus bar assembly having multiple sections wherein adjacent sections are coupled to the bus bar assembly via a bus bar link and wherein each section comprises a set of distribution cables connected to a single feeder cable and a plurality of connecting means for connecting the set of distribution cables to the feeder cable for power distribution, said connecting means being detachable allowing making and breaking of link between the feeder cable and distribution cables to enable uninterrupted power supply in a fault condition.

[0010] In another embodiment, a method of assembling a power distribution unit is provided. The method comprises steps of positioning a housing assembly that includes a bus bar assembly, the bus bar assembly allowing a plurality of distribution cables to be connected to a feeder cable, the bus bar assembly having multiple sections wherein adjacent sections are coupled to the bus bar assembly via a bus bar link and wherein each section comprises a set of distribution cables connected to single feeder cable, and a plurality of connecting means for connecting the set of distribution cables to the feeder cable for power distribution, said connecting means being detachable allowing making and breaking of link between the feeder cable and distribution cables to enable uninterrupted power supply in a fault condition; assembling at least one connector with the bus bar assembly so as to enable external connection of the feeder cable and the distribution cables to the bus bar assembly; connecting the feeder cable and the distribution cables to the bus bar assembly and positioning an enclosure assembly over the housing assembly.

[0011] Various other features and advantages of the invention will be made apparent from the following detailed description and the drawings.

BRIEF DESCRIPTION OF THE DRAWINGS

[0012] Reference will be made to embodiments of the invention, examples of which may be illustrated in the accompanying figures. These figures are intended to be illustrative, not limiting. Although the invention is generally described in the context of these embodiments, it should be understood that it is not intended to limit the scope of the invention to these particular embodiments.

[0013] FIG. 1 shows a schematic diagram of a power distribution unit as described in one embodiment of the invention; and

[0014] FIG. 2 shows an indicative diagram representing multiple sections of the power distribution unit described in FIG. 1.

[0015] Persons skilled in the art will appreciate that elements in the figures are illustrated for simplicity and clarity and may have not been drawn to scale. For example, the dimensions of some of the elements in the figure may be exaggerated relative to other elements to help to improve understanding of various exemplary embodiments of the present disclosure.

DETAILED DESCRIPTION OF THE INVENTION

[0016] Various embodiments of the invention provide a power distribution unit. The power distribution unit comprises multiple sections that are connected to a bus bar assembly via a bus bar link and wherein multiple distribution cables are coupled to a single feeder cable in each section using one or more detachable connecting means so as to facilitate uninterrupted power supply in a fault condition.

[0017] Referring to FIG. 1 a power distribution unit 100 is provided in accordance with an embodiment of the invention. As shown, the power distribution unit 100 includes a housing assembly 110, a bus bar assembly 120 and plurality of connecting means 30 such as a fuse or a connecting/disconnecting link or a switch.

[0018] In accordance with an embodiment of the invention, the housing assembly 110 is formed of a top cover 112, a bottom cover 114 and side covers 116, 118 respectively. The top cover 112 and the bottom cover 114 are configured to be mated one on top of the other. The bottom cover 114 is a flat surface capable of accommodating at least one bus bar assembly 120. In one embodiment, the power distribution unit 100 formed is a unitary chamber, wherein the housing assembly 110 is made of molded plastic.

[0019] As shown in FIG. 1, the top cover 112 has an opening for providing access to the bus bar assembly 120. The side covers 116, 118 are assembled on each side of the mated top and bottom covers 112, 114 respectively. Further, the side covers 116 and 118 comprise provision for allowing cables to be coupled to the bus bar assembly 120. Advantageously, the housing assembly 110 of the power distribution unit 100 can accommodate multiple bus bar assemblies (such as 120).

[0020] In accordance with an embodiment of the invention, each bus bar assembly 120 allows a plurality of distribution cables 20 to be connected to a feeder cable 10. With reference to FIG. 2, the power distribution unit 100 comprises multiple sections 102 and 103 and each section 102 has a bus bar link 122 connected to the bus bar assembly 120. Further, each section 102 comprises multiple distribution cables 20 connected to a single feeder cable 10 using a connecting means 30 such as fuse or a connecting/disconnecting link.

[0021] Therefore, plurality of connecting means 30 of the power distribution unit 100 are configured for connecting the feeder cable 10 to multiple distribution cables 20 in each section 102 thereby connecting multiple sections 102 and 103 to the bus bar assembly 120 for power distribution. Advantageously, the connecting means 30 is detachable allowing making and breaking of link between the feeder cable 10 and the distribution cables 20 to enable uninterrupted power supply in a fault condition.

[0022] Though, in FIG. 2 the power distribution unit 100 is shown as having two sections 102 and 103 on either side of the bus bar assembly 120, skilled artisans shall appreciate that the power distribution unit 100 may comprise many such sections 102 and 103 that are distributed on either side of the bus bar assembly 120.

[0023] Further in FIG. 2, the power distribution unit 100 is shown as accommodating total of eight cable entries i.e. two for feeder cables 10 and six for distribution cables 20. Three distribution cables 20 that are positioned on the opposite side as that of the feeder cable 10 are connected to each feeder cable 10. However, FIG. 1 shows the three distribution cables 20 to be connected on the same side as that of the feeder cable 10. Thus, it is to be understood that positioning of the distribution cables 20 with respect to the feeder cable 10 is flexible and varied based on need.

[0024] As can be understood, the number of feeder cables 10 is not restricted to two and number of distribution cables 20 is not restricted to six. Thus, the power distribution unit 100 can have multiple sections 102 and 103 and therefore requisite number of feeder cables 10 and distribution cables 20 based on the user requirement. In one embodiment, the feeder cable 10 is of the size of about 300 sq.mm and size of individual distribution cable 20 is in the range of about 35 sq. mm to about 150 sq.mm.

[0025] Further, the feeder cable 10 and the distribution cables 20 are connected to the bus bar assembly 120 through mechanical connectors such as clamps (not shown). Mechanical connectors allow the distribution cable 20 and the feeder cable 10 to be replaced on-site with a new cable. Further, clamps (not shown), fuses and links are formed with conductors such as copper and aluminum.

[0026] The feeder cable 10 may be drawn from one of a transformer and a substation and the distribution cables 20 may be directed to consumer lines. Alternatively, one of the distribution cables 20 may be configured to feed another power distribution system (not shown). Accordingly, the feeder cable 10 may also be drawn from yet another power distribution system (not shown).

[0027] In one embodiment, each of the feeder cable 10 and the distribution cable 20 are three phase cables and connecting means 30 are provided for each phase.

[0028] In an embodiment of the invention, the power distribution unit 100 provides uninterrupted power supply even in a fault condition where one feeder cable 10 is faulty, by allowing disconnection of the faulty feeder cable 10 only. The disconnection of the faulty feeder cable 10 can be achieved by disconnecting the connecting means 30 that connects the faulty feeder cable 10 to the respective set of distribution cables 20 and subsequently connecting the section 102 that houses faulty feeder cable 10 to the adjacent section 103 via the bus bar link 122.

[0029] The power distribution unit 100 further comprises a neutral bus 130, a phase separator 140 and an enclosure (not shown). The phase separator 140 is employed for separating each phase of the power supply. The enclosure (not shown) is configured for being assembled with the housing assembly 110 for enclosing the power distribution unit 100.

[0030] In one embodiment, the housing assembly 110 is pre-casted and connectors 50 are assembled to the bus bar assembly 120 at the site of installation. The connectors 50 extend from the interior of the housing assembly 110 into cable receiving spaces. This facilitates configuring the number of connections to be provided based on user requirement.

[0031] Further, the bus bar assembly 120 may be extended outside the housing assembly 110. Such extension of the bus bar assembly 120 and usage of the connectors 50 facilitates replacement of faulty feeder cable 10 or distribution cable 20, without replacing the power distribution unit 100.

[0032] Further, in one embodiment, unused connectors 50 can be filled with cold casting material that is based on hydrocarbon resins that allows installation at low temperature. The hydrocarbon resin can be re-opened following the need for making a connection. The usage of this re-openable type of resin facilitates easy alteration of the number of outgoing cables i.e., distribution cables 20.

[0033] In an embodiment of the invention, the power distribution unit 100 can be installed underground without the risk of water or moisture getting into the power distribution unit 100. Accordingly, the power distribution unit 100 comprises an enclosure assembly 150 adapted to the housing assembly 110. The enclosure assembly 150 comprises an enclosure 152, a plurality of side wall protection covers 154, a locking member 156, a metal plate 158 and outer slabs 160. The enclosure 152 is configured to be assembled with the opening of the top cover 112. Further, the side wall protection covers 154 are fitted on top of the enclosure 152. The locking member 156 is then fitted on top of the enclosure 152 such that the locking member 156 locks the enclosure 152. Further the metal plate 158, and outer slabs 160 are installed on top of the locking member 156 and the top-most side cover for enclosing the power distribution unit 100. The enclosure assembly 150 provides a rigid chamber preventing water and moisture from entering the power distribution unit 100.

[0034] In one embodiment, the enclosure assembly 150 is made of a molded plastic material such as, for example, Acrylonitrile Butadiene Styrene (ABS) plastic or high-density polyethylene plastic. This is advantageous as it is light weight, non-conductive and is resistant to oxidation.

[0035] Some of the advantages provided by the power distribution unit 100 described herein include:

[0036] The power distribution unit described herein provides uninterrupted power supply even in a fault condition, where one feeder or distribution cable is faulty, by allowing disconnection of the faulty cable only. The usage of power distribution unit within the distribution network increases the flexibility as different parts of the networks can be energized or de-energized as required thereby reducing service interruptions to consumers.

[0037] The housing assembly is pre-casted and connectors are assembled to the bus bar assembly at the site of installation. Further, the bus bar assembly may be extended outside the housing assembly. This facilitates configuring the number of connections to be provided based on user requirement.

[0038] The power distribution unit is configured for connecting multiple feeder cables each of which are coupled to a set of distribution cables for power distribution. The increase in the provision for feeder cable connection increases the number of outgoing supplies in the form of distribution cables. Therefore, a single power distribution unit can be employed for supplying power to increased number of consumers.

[0039] Single resin casting eliminates moisture ingress issues that are associated with multiple cast power distribution units.

[0040] Compact modular concept reduces weight and space required for positioning the power distribution unit making installation possible in congested areas while reducing excavation and reinstatement costs.

[0041] The cost of production of the power distribution unit is less, since it is in mold form and easy to install.

[0042] Further, the power distribution unit described herein is suitable for underground installations and hence eliminates the need for a platform that is required for mounting the power distribution unit.

[0043] Thus, it will be appreciated by those skilled in the art that the present invention can be embodied in other specific forms without departing from the spirit or essential characteristics thereof. The presently disclosed embodiments are therefore considered in all respects to be illustrative and not restricted. The scope of the invention is indicated by the appended claims rather than the foregoing description and all changes that come within the meaning and range and equivalence thereof are intended to be embraced therein.
,CLAIMS:CLAIMS

What is claimed is:

1. A power distribution unit (100) comprising:
at least one bus bar assembly (120) provided within a housing assembly (110), the bus bar assembly (120) allowing a plurality of distribution cables (20) to be connected to a feeder cable (10), the bus bar assembly (120) having multiple sections wherein adjacent sections are coupled to the bus bar assembly (120) via a bus bar link (122) and wherein each section comprises a set of distribution cables (20) connected to single feeder cable (10); and
a plurality of connecting means (30) for connecting the set of distribution cables (20) to the feeder cable (10) for power distribution, said connecting means (30) being detachable allowing making and breaking of link between the feeder cable (10) and distribution cables (20) to enable uninterrupted power supply in a fault condition;
wherein the housing assembly (110) comprises at least one cable connector (50) so as to enable external connection of the feeder cable (10) and the distribution cables (20).
2. The power distribution unit (100) of claim 1, wherein the connecting means (30) is a fuse or a connecting/disconnecting link.

3. The power distribution unit (100) of claim 1, further comprising at least one clamp for coupling the feeder cable (10) and the distribution cables (20) to the bus bar assembly (120).

4. The power distribution unit (100) of claim 1, further comprising a phase separator for separating each section.
5. The power distribution unit (100) of claim 1, further comprising a diving bell enclosure for enclosing the power distribution unit (100).

6. The power distribution unit (100) as claimed in any of the preceding claims is an underground power distribution unit.

7. A method of assembling a power distribution unit (100), the method comprising steps of:
positioning a housing assembly (110) including a bus bar assembly (120), the bus bar assembly (120) allowing a plurality of distribution cables (20) to be connected to a feeder cable (10), the bus bar assembly (120) having multiple sections wherein adjacent sections are coupled to the bus bar assembly (120) via a bus bar link (122) and wherein each section comprises a set of distribution cables (20) connected to single feeder cable (10), and a plurality of connecting means (30) for connecting the set of distribution cables (20) to the feeder cable (10) for power distribution, said connecting means (30) being detachable allowing making and breaking of link between the feeder cable (10) and distribution cables (20) to enable uninterrupted power supply in a fault condition;
assembling at least one connector (50) with the bus bar assembly (120) so as to enable external connection of the feeder cable (10) and the distribution cables (20) to the bus bar assembly (120);
connecting the feeder cable (10) and the distribution cables (20) to the bus bar assembly (120); and
positioning an enclosure assembly (150) over the housing assembly (110).

8. The method of claim 7, further comprising enclosing one or more unused cable outlets with a compound so as to enable desired cable connection.