ADVANTAGES AND APPLICATION

The advantage of assembling the three conductors around a supporting messenger are as follows :

• When assembled conductors are used there is no need to use any connecting device, inasmuch as the phases are supported by the messenger.
• When cabling the conductors around the messenger is not practical, due to the large diameter of the conductors, they are strung to the supporting messenger by means of clamps.
• The entire assembly is significantly lighter and no filling compounds are used. In the event of mechanical damage it is usually to one phase only, without affecting the other two conductors as would be the case in a three conductor cable assembly.
• In wooded areas there are advantages when compared with bare cable installations. Since the conductors are insulated there is no risk of having accidental contacts to ground through the branches of the trees. With this type of construction less aerial space is required, and therefore less tree pruning is necessery.
• In areas where icy conditions prevail, the weight of a possible overload is not in proportion to the diameter of the cable, therefore in a line consisting of three bare cables the overload due to the ice is three times that of a line having a three insulated conductor assembly.
• When using bare conductors in areas of high industrial pollution or subject to salt conditions by the sea high maintenance is incurred due to insulator damage..
• In rocky areas where trench digging would be too costly. In the feeding of substations of small villages, in which use of bare lines is too risky and the laying of buried cables is too costly.

CONSTRUCTION

The overhead network cables consist of three single core cables, type XLPE/PVC, assembled around a massanger.

The single core cable consist of aluminium compacted stranded conductor insulated with cross-linked polyethylene ( XLPE ), extruded semiconducting layers of XLPE under and over isolation, metallic screen of copper wires and helix copper tape and outer sunlight resistant polyvinyl chloride ( PVC ) or polyethylene ( PE ) sheath in black colour.

TESTS

The overhead networks cables produced by FKS are tested according to IEC 502/94.