MV/LV Aerial Bundled Cable & Conductor Accessories are used in overhead distribution line system which can be categorized as either low voltage or medium voltage. Low voltage lines have an operating voltage up to 1kV. They may be either bare or covered. Covered lines may either be unscreened or fully insulated ABC System. In LV Aerial application,fully insulated ABC are increasingly used as almost the only alternative to bare overhead or underground system in different parts of the world because of their outstanding features.
The pictures on the left show MV/LV Aerial Bundled Cable & Conductor Accessories.
FEATURES OF LV ABC SYSTEM
The phase conductors are fully insulated. The messenger may be either bare or insulated depending on type of system being followed :-
- More than one conductor is part of the bundle. Commonly they are four comprising of three phases and one neutral messenger. Very often 5 conductor can be used for street lighting is also a part of the bundle.
- They are self-supporting and suspended between supports (generally existing poles)
- They can be installed through forest areas without cutting of aisles prescribed for overhead lines.
- ABC Bundle and accessories being fully insulated protect lineman actively as the design is touch proof.
- They are twisted together to form a bundle as there is no requirement of phase to phase clearance. Individual cores are separated only at dead ends, supports,joints and tap-off
- Prescribed clearance required for Bare Conductors under NEC/NESC/VDE/EDF codes not applicable here and the same may be reduced without limitation as long as insulation does not become vulnerable to mechanical damage.
- The conductors and joints are fully water proof. All joints and taps are required by most standards to be tested to withstand 6 kV RMS while being immersed in water of defined maximum restivity and prescribed minimum pressure.
- Lower voltage drop and higher current carrying capacity. For supply cases vulnerable to voltage problem the use of ABC system increases transmission capacity because of very low inductive resistance as compared to ohmic resistance.