DESC:Background of the Invention

Field of the Invention

The present invention relates to the laying of cables in a Power plant in hilly and rocky terrain and more specifically to a solar power plant facilitated by systematically developed cable tray system of short height over the ground.

Description of the Related Art

Conventionally, in a solar power plant DC (direct current) is converted into AC (alternating current), which is transmitted to the grid and further to the end users through cables. The solar power plant consists of huge quantum of cables of different size, material and load, which carries current and runs across the plant area. Generally for 1MW block around 1~2 kilometers of cables are laid.

The conventional method of laying of cables in the solar power plant is buried under the ground. A trench of approximately 1.2~1.5m deep and 1.0~1.2m wide is excavated and sand is laid at the base to prevent the cables from bottom puncturing. After laying of cables, another layer of sand say 200mm is placed over the cables. The burnt bricks or precast slabs are then placed over the sand. The complete process is very lengthy and in sequential order. Few drawbacks involved in cable lying in buried form are:-

• The excavation in the rock requires blasting and special tools. Blasting over the entire length of cable laying is cumbersome and risky.
• Blasting may also affect adjacent civil foundations.
• The excavated earth (i.e. rock in hilly terrain) cannot be completely used for the backfilling. The same needs to be disposed outside the plant boundary.
• The time consumption to carry out the civil and electrical works is enormous.
• The cost involved is around 2000~2500 INR/meter, which is almost 100% extra as compared to the cost involved in the flat and normal soil conditions.
• To carry out the maintenance work of cables the complete process is to be executed again.
• The heat dissipation from the cable in rocky terrain is poor and may thus increase cable faults.

Another method of cable routing is by hanging the conductors through the elevated towers. The system consists of structural steel towers of 7~10m height. The conductors are hanged to the towers to carry the current. These towers designed required deep and wide foundations and additional space for cable / tower corridor. The following are the drawbacks of the system:-

• The installation of this system in the solar power plant develops shadow over the solar panels. This reduces the capacity utilization factor (CUF) of the solar power plant significantly.
• As an alternative, to avoid shadow a cable / tower is left all around. This also results into more land requirement.
• The civil works for tower foundations and super structure are costly.
• The maintenance of the cables is very difficult.

Thereby the concept of laying of cables over the ground on the cable trays of short height is invented. The cable trays are designed for a short height of 250~450mm above the ground and below the minimum height of solar panels to avoid the losses due to shading effect. The cable tray system comprises of columns, rafters, runners, rungs, connection angles, cap and accessories like fasteners i.e. nut-bolt. The system is designed for a maintenance free life span of more than 10 years to carry the dead loads from cables and wind load acting over the tray surface. Short pile with part of column acting as insert is the foundation system of the invented art.

Objects of the invention

Accordingly, it is a principal object of the present invention to provide a robust design system to withstand dead loads and wind pressure.

It is an another object of the present invention to minimize the cost of the system as compared to the conventional buried system and in which the maintenance of the cables is easy.

It is yet another object of the present invention to provide a system that is best suited for rocky and hilly terrain.

Additional advantages, objects and features of the invention will be set forth in part in the description which follows and in part will become apparent to those having ordinary skill in the art upon examination of the following or may be learned from practice of the invention may be realized and attained by the structure particularly pointed out in the written description as well as the accompanying drawings.

Brief Description of the Accompanying Drawings

The invention will be described in conjunction with the accompanying drawings, in which:

Fig. 1 illustrates the cable laying system, in accordance with an embodiment of the present invention.

Fig. 2 illustrates the overall three-dimensional view of the cable laying system, in accordance with an embodiment of the present invention;

Fig. 3 illustrates a closer view and with specially related to the fixing details, in accordance with an embodiment of the present invention.

Skilled artisans will appreciate that elements in the drawings are illustrated for simplicity and have not necessarily been drawn to scale. For example, the dimensions of some of the elements in the drawings may be exaggerated relative to other elements to help to improve understanding of embodiments of the present invention.
Detailed Description of the Invention

While the invention is susceptible to various modifications and alternative forms, specific embodiment thereof has been shown by way of example in the drawings and will be described in detail below. It should be understood, however that it is not intended to limit the invention to the particular forms disclosed, but on the contrary, the invention is to cover all modifications, equivalents, and alternative falling within the spirit and the scope of the invention as defined by the appended claims.

Before describing in detail the various embodiments of the present invention it may be observed that the novelty and inventive step are in accordance with the present invention resides in the construction of cable laying system. It is to be noted that persons skilled in the art can be motivated from the present invention and modify the various constructions of the cable system. However, such modifications should be construed within the scope and spirit of the invention.

Accordingly, the drawings are showing only those specific details that are pertinent to understanding the embodiments of the present invention so as not to obscure the disclosure with details that will be readily apparent to persons of ordinary skill in the art having benefit of the description herein.

The terms “comprises”, “comprising”, or any other variations thereof, are intended to cover a non-exclusive inclusion, such that a setup, device that comprises a list of components does not include only those components but may include other components not expressly listed or inherent to such setup or device. In other words, one or more elements in a system or apparatus proceeded by “comprises… a” does not, without more constraints, preclude the existence of other elements or additional elements in the apparatus. The following paragraphs explain present invention with respect to a cable laying system for a solar power plant in hilly and rocky terrain. The invention in respect of the same may be deduced accordingly.

Accordingly, the present invention relates to a cable laying system for a solar power plant in hilly and rocky terrain, said system comprising:
a column being the supporting part of system as well as the short pile foundation placed at a predetermined distance;
a rafter being placed over the said column with slotted holes in the horizontal direction for maintaining the alignment;
tray assembly comprising of runners, rungs and a cap being bolted over said rafter by the connection plate;
said tray assembly being put with the vertical slotted holes to adjust the terrain level difference and alignment.

In an embodiment of the present invention, rungs are welded to said runners at regular intervals to support the cables.

In another embodiment of the present invention, the rungs also have holes on the top surface to help in dissipation of heat from the cables.

In still another embodiment of the present invention, the cap is bolted at the site after laying the cables into the tray and protects the cables from direct environmental attacks like rain, sun etc.

In yet another embodiment of the present invention the width of the cable tray is developed based on the number of cables to be laid.

In a further embodiment of the present invention, the span of column support is developed based on the load, width of cable tray, height of tray and soil conditions.

In another embodiment of the present invention, the column is inserted inside the circular foundation hole made with suitable mechanical means and is leveled properly to maintain the longitudinal and vertical alignment of the tray system, and is then cast with concrete.

In still another embodiment of the present invention, the rafter is connected to said column which later supports the mounted cable tray assembly.

In yet another embodiment of the present invention the tray assembly is placed over said rafter and is connected by connection angles taking care of the longitudinal and vertical alignment.

The complete cable tray system according to the present invention comprises of only six components. The material used for the cable tray system is made up of Hot rolled steel sheets (of order 1.6 to 2mm thick) fabricated, galvanized, assembled and installed at site. The thickness of galvanization may be considered based on the environmental conditions affecting it.

The column (1) is used as the supporting part of system as well as the short pile foundation. The rafter (2) is placed over the column (1) with slotted holes in horizontal direction for maintaining the alignment. The tray assembly comprises of runners (5), rungs (4) and cap (6) is then bolted over the rafter (2) by the connection plate (3). The tray assembly is put with the vertical slotted holes to adjust the terrain level difference and alignment. The rungs (4) are welded to the runners (5) at the fabrication workshop at regular intervals for supporting the cables, also contains holes on the top surface to help in dissipation of heat from cables. The cap (6) is bolted at site after laying the cables into the tray and protects the cables from the direct environmental attacks like rain, sun, etc. The width of cable tray is developed based on the number of cables to be laid. The span of column support (1) is developed based on the load, width of cable tray, height of tray and soil conditions.

Short pile foundation system of around 500~1000mm depth may be designed as per geo-tech condition. The column (1) is inserted inside the circular foundation hole made with suitable mechanical means and is leveled properly to maintain the longitudinal and vertical alignment of the tray system, and is then cast with concrete. The rafter (2) is connected to column (1) which later supports the mounted cable tray assembly. The tray assembly is placed over the rafter (2) and connected by connection angles (3) taking care of the longitudinal and vertical alignment.
Advantages over the Prior art

The main advantages of the present invention are its user friendly robust design system to withstand dead loads and wind pressure. Another advantage of the present invention is that the execution is very fast and is designed as per BIS standards. Another advantage of the present invention is its cost effectiveness as compared to the conventional buried system. Another advantage of the present invention is that it fits into the erection sequence of the solar power plant. Yet another advantage in the present invention is that it requires less land.

It will be understood from the forgoing that the present invention provides an efficient solar power plant facilitated by systematically developed cable tray system. More important, this feature of the invention has been achieved in a relatively simple and in a cost effective manner.

As those skilled in the art will understand, there are many variations or alterations of the device that can be made using the principles and devices discovered by the inventor. Therefore, the above description is not intended to be limiting but, instead, illustrative. Accordingly, it is the intention of the inventor to embrace all such variations and alterations as fall within the spirit and broad scope of the invention.

,CLAIMS:1. A cable laying system for a solar power plant in hilly and rocky terrain, said system comprising:
a column (1) being the supporting part of system as well as the short pile foundation placed at a predetermined distance;
a rafter (2) being placed over the said column (1) with slotted holes in the horizontal direction for maintaining the alignment;
tray assembly comprising of runners (5), rungs (4) and a cap (6) being bolted over said rafter (2) by the connection plate (3);
said tray assembly being put with the vertical slotted holes to adjust the terrain level difference and alignment.

2. The system as claimed in claim 1, wherein said rungs (4) are welded to said runners at regular intervals to support the cables.

3. The system as claimed in claim 2, wherein said rungs (4) also has holes on the top surface to help in dissipation of heat from the cables.

4. The system as claimed in claim 1, wherein the cap (6) is bolted at the site after laying the cables into the tray and protects the cables from direct environmental attacks like rain, sun etc.

5. The system as claimed in claim 1, wherein the width of the cable tray is developed based on the number of cables to be laid.

6. The system as claimed in claim 1, wherein the span of column support (1) is developed based on the load, width of cable tray, height of tray and soil conditions.

7. The system as claimed in claim 1, wherein said column (1) is inserted inside the circular foundation hole made with suitable mechanical means and is leveled properly to maintain the longitudinal and vertical alignment of the tray system, and is then cast with concrete.

8. The system as claimed in claim 1, wherein said rafter (2) is connected to said column (1) which later supports the mounted cable tray assembly.

9. The system as claimed in claim 1, wherein said tray assembly is placed over said rafter (2) and is connected by connection angles (3) taking care of the longitudinal and vertical alignment.