LT Aerial Bunched Cable LT Aerial Bunched Cable, LT Aerial Bunched Cable Manufacturers

LT Aerial bunched Cable 1100 Volts (3.5 Core). Reference Standard : IS : 14255/95

Sl. No. Description   3 x 25 + 1 x 16 + 1 x 35 3 x 25 + 1 x 16 + 1 x 35 3 x 50 + 1 x 25 + 1 x 35 3 x 70 + 1 x 35 + 1 x 55 3 x 95 + 1 x 50 + 1 x 55
1. Power/Neutral core:
1.1 Conductors :
  a) Nom. Cross Sectional Area
  i) Power cores (Sq. mm) 25 35 50 70 95
  ii) Neutral core (Sq. mm) 16 16 25 35 50
  b) Max. D.C. resistance of conductor
  i) Power cores (Ohm/Km) 1.200 0.868 0.641 0.443 0.320
  ii) Neutral core (Ohm/Km) 1.910 1.910 1.200 0.868 0.641
  c) Approx. diameter of conductor
  i) Power cores (mm) 6.200 7.300 8.350 10.100 12.000
  ii) Neutral core (mm) 5.100 5.100 6.200 7.300 8.350
1.2 Insulation :
  Minimum thickness :
  i) Power cores (mm) 0.980 0.980 1.25 1.25 1.25
  ii) Neutral core (mm) 0.980 0.980 0.980 1.25 1.25
2 Messenger Wire (Bare) :            
  i) Nom. Cross sectional area (Sq. mm) 35 35 35 55 55
  ii) Approx. breaking load (KN) 9.80 9.80 9.80 16.03 16.03
3 Current ratings.            
  Continuous current carrying capacity of
cable in Air at Ambient temp 40 C
(Amps) 99 122 149 190 235
4 Approx. weight (Kg/Km) 580 665 810 1165 1430
5 Number of cores :            
  i) Power cores (No.) : 3  
  ii) Neutral core (No.) : 1
  iii) Bare messenger (No.) : 1
6. Derating factor :
  Derating factors for variation in air temp.
  Air Temp. (C) 30 35 40 45 50 55
  Rating factor 1.12 1.06 1.00 0.94 0.88 0.83
7.1 Identification of Power cores :   By Providing ridges on the insulation.
7.2 Laying :   Three power cores and one neutral core shall be suitably twisted around Aluminium Alloy messenger.
8. Details of the Power/Neutral core :
8.1 Conductor :
  a) Material   Aluminium to IS : 8130/84
  b) Flexibility class as per IS:8130/84   Class-2
  c) Form of conductor   Compacted circular.
8.2 Insulation :
  a) Material   Cross linked Polyethylene to IS:7098(I)/88
  b) Colour of insulation   Black
9. Details of the Messenger wire (Bare)
  a) Material   Aluminium Alloy Wire to IS : 398(IV)
  b) Form of conductor   Stranded circular / Compacted Circular.

LT Aerial bunched Cable 1100 Volts (4 Core). Reference Standard : IS : 14255/95

Sl. No. Description   3 x 25+1 x 25+1 x 35 3 x 25+1 x 35+1 x 35 3 x 50+1 x 50+1 x 35 3 x 70+1 x 70+1 x 55 3 x 95+1 x 95+1 x 55
1. Power/Neutral core:
1.1 Conductors :
  a) Nom. Cross Sectional Area
  i) Power cores (Sq. mm) 25 35 50 70 95
  ii) Neutral core (Sq. mm) 25 35 50 70 95
b) Max. D.C. resistance of conductor at 20C
  i) Power cores (Ohm/Km) 1.200 0.868 0.641 0.443 0.320
  ii) Neutral core (Ohm/Km) 1.200 0.868 0.641 0.443 0.320
c) Approx. diameter of conductor
  i) Power cores (mm) 6.200 7.300 8.350 10.100 12.000
  ii) Neutral core (mm) 6.200 7.300 8.350 10.100 12.000
1.2 Insulation :
  Minimum thickness :
  i) Power cores (mm) 0.980 0.980 1.25 1.25 1.25
  ii) Neutral core (mm) 0.980 0.980 0.980 1.25 1.25
2 Messenger Wire (Bare) :            
  i) Nom. Cross sectional area (Sq. mm) 35 35 35 55 55
  ii) Approx. breaking load (KN) 9.8 9.8 9.8 16.03 16.03
3 Current ratings.
  Continuous current carrying capacity of
cable in Air at Ambient temp 40C
(Amps) 99 122 149 190 235
4 Approx. weight (Kg/Km) 610 725 880 1270 1570
5 Number of cores :
  i) Power cores (No.) : 3          
  ii) Neutral core (No.) : 1          
  iii) Bare messenger (No.) : 1          
6. Derating factor :
  Derating factors for variation in air temp.
  Air Temp. (C) 30 35 40 45 50 55
  Rating factor 1.12 1.06 1.00 0.94 0.88 0.83
7.1 Identification of Power cores : By Providing ridges on the insulation.
7.2 Laying : Three power cores and one neutral core shall be suitably twisted around Aluminium Alloy messenger.
8. Details of the Power/Neutral core :
8.1 Conductor :
  a) Material Aluminium to IS : 8130/84
  b) Flexibility class as per IS:8130/84 Class-2
  c) Form of conductor Compacted circular.
8.2 Insulation :
  a) Material Cross linked Polyethylene to IS:7098(I)/88
  b) Colour of insulation Black
9. Details of the Messenger wire (Bare)
  a) Material Aluminium Alloy Wire to IS : 398(IV)
  b) Form of conductor Stranded circular / Compacted Circular.

LT AERIAL BUNCHED CABLE

Aerial Bunched Cable (ABC) is a very novel concept for overhead Power distribution. ABC provides higher safety and reliability compared to bare conductor overhead distribution system. The other advanctages are lower power losses and system economy by reducing installation, maintenance and operation cost. This system is ideal for rural distribution and specially suitable in difficult terrains like hilly areas, forest and coastal areas etc.

ABC is also considered as a better choice for power distribution in densely populated areas where laying of underground cable is either difficult or extremely expensive. This is attributed by narrow lanes and by-lanes of congested urban areas. Needless to mention that ABC is a better choice due to the flexibility of re-routing demand, should there be any changes in urban development plan.

Bare overhead Transmission lines are more prone to system failures causing immense loss and inconvenience to the consumers.

Aerial Bunched Cables systems for both HT & LT have been introduced across the globe to arrest such problem. It is basically a compromise between Insulated Power Cable system and bare overhead conductor.

There are 3 or 4 Power carrying conductors suitably insulated and laid around a bare or insulated Neutral/Earth conductor. This earth/neutral conductor carries the entire weight of the cable when hanged on Transmission poles/towers suitably.

The chances of faults are reduced to a great extent because the conductors are insulated. However, it lacks the Safety and mechanical strength of Underground cables. The fact that ABC runs overhead and hence it is never subjected to the mechanical abuses that an underground cable undergoes.

ABC ensures good protection against ground and line faults ensuring system reliability, increased system efficiency compared to bare overhead lines. The problem of free clearance is also minimized. ABC system hinders tampering with power-line like hooking resulting in efficient Power utilization.

Advantages :

  • Easier Installation particularly in congested, forest or Hilly areas.
  • Saving in cost of Poles, Insulators, cross-arms etc.
  • Human Safety in case of accidental contacts.
  • Water proof system, no corrosion.
  • Syatem reliability hence customer satisfaction.
  • Reduced clearance.

Insulated Neutral :

In low voltage networks, in case of unbalanced load on the 3 phases, a current can flow in the neutral. This flow of current causes a voltage to be present in the neutral. This voltage can reach dangerous levels even in 'Earthed' conditions.

It is observed that the permissible voltage shift between neutral and earth can go up 100 volts! This surely establishes the need for an insulated neutral. Moreover, parallels can be drawn with the underground cables. A single insulation damage on the conductor will not necessarily trip the system, unless an adjacent conductor also suffers an insulation damage at the same point. Unlike in underground cables system there are lot of relative movements between the conductors leading to abrasion which more likely to damage the adjoining insulation if the netural is not insulated