132 kV Underground Cable Installation
Installation of 132 kV Underground Cables
The successful bidder shall carry out all activities connected with the laying arid installation of the XLPE power cables and completion of the work for which the project is intended and to the full satisfaction of the purchaser.
The bidder shall submit a CPM to complete the cable installation work.
This part covers routs survey proposed method of cable laying directly buried/cables in ducts/pipes at road crossings excavation of trenches and construction of joint bays as per requirement of the field conditions.
The scope also includes supply of all requisite labour tools and materials like sand bricks pipes joint marker and route markers and all other consumables required for the completion of work.
The successful contractor shall make a detailed survey of the cable route after the award of contract of decide the requirements of the following.
- Cable delivery length per drum
- Location of joint bay positions.
- Quality of joints required
- Design of cable trench / ducts for road crossing and drainage crossing etc.
Location of Joint bays
The location of joint bays should be carefully decided to avoid traffic hazards, collection of sub-soil water and any possibility of flooding due to storm water. The joint bays located should be easily accessible for inspection and test.
Installation of underground cables
Cable drum shall be unloaded handled and stored in the approved manner on hard and well drained surfaced so that they must not sink. In no case shall the drum be stored flat i.e. with flange horizontal rolling of drums shall be avoided. For unreeling of cables the drum shall be mounted on suitable jacks or on wheels. All possible care shall be taken during unreeling and laying to avoid damage due to twist kink or sharp bends. Cables shall be pulled on cable rollers of approved design. Cable laying procedure shall be submitted along with technical proposal. Bending radius for cables shall be as per manufacturer’s recommendations. Manufacturer’s instructions shall be strictly adhered to and necessary conducting medium shall be provided over the cable outer sheath for checking the healthiness of outer sheath applied.
Cable trenches shall be constructed for directly buried cables. Construction of trench for cable shall also include excavation preparation of sieved sand bedding riddled soil cover supply and installation of concrete protective covers, back filling and compacting supply band installation of route marker and joint marker.
Back filling shall be done by impacted viti sand the excavated soil shall have to be removed from the site by the contractor.
Cables shall be laid i trefoil formation as per enclosed drawing.
Installation of cables shall be done as per drawings enclosed. The cables shall be surrounded by well compacted sand of thickness shown in the drawing in all directions form cable surface for protection against damage. Concrete protective covers (RCC slabs), as per drawings; shall be installed over the compacted over the compacted sand over the cables surface.
Cable jointing and termination work shall be carried out by either manufacturer’s cable jointer of experienced directions from cable surface for protection against damage. Concrete protective covers (RCC slabs) as per drawings shall be installed over the compacted sand over the cable surface.
Cable jointing and termination work shall be carried out by either manufacturer’s cable jointer or experienced cable jointer certified by the manufacturer who shall have adequate skill and experience in jointing and termination of 132 kV or higher voltage grade XLPE cables. Details of cable jointer shall be furnished with the offer.
Bidder shall carry out the earthing of sheath/screen at both ends of termination using insulated sheath bonding (Earthing) cable of required size. The sheath / screen shall be bonded to the earth station through disconnecting type link boxes.