AB cable issues and solutions , estimation, fault finding
Posted: Mon Dec 31, 2018 12:47 pm
Here we want to discuss more on ABC. AS we know in the IPDS scheme we are drawing close to 2 laks kilometer of various AB cables. So lets have a discussion on its various sides.
Design and construction
Messanger
Conductor
a)Aluminum Alloy, Aluminum Conductor, Aluminum Conductor Steel Reinforced
b) Insulation: PVC
11KV ABC Cable:
a) Conductor: Hard Drawn Aluminum
b) Conductor Screen: Semi-Conductive Compound
c) Insulation: Cross-Linked Polyethylene
d) Insulation Screen: Sem-conductive Compound
e) Metallic Screen: Copper Tape
f) Outer Sheath: Black PVC + Ultra Violet Resistant
Semi conducting Layer
The material is a polymer base mixed with a conductivity imparting agents such as carbon black.
Semi-conducting compounds also have the effect of fillings in the interstices of the conductor giving a smooth surface for insulation.
semiconductor behaves as conductors when temperature rises so when the HT cables is on load , Its conductor temperature rises due to this the semicon layer which is on conductor behaves like conductor as a result overall cross-section area is increased
The second silicon layer which is over XLPE on temperature rise behaves a conductor and used for dissipating heat out of conductor as the cable heat due to load. The semi-conductive layer also serves to even out the stresses associated with partial discharge which would otherwise attack the insulation at specific points.
It acts a smooth transition between each layers
It protects XLPE insulation from moisture abosrption.
components of HV ABC
Stranded Aluminium round Phase conductor - IS: 398
• Conductor screen of semiconducting compound (0.5 mm thick)
• Polyethylene (XLPE) Insulation - IS:7098 (Pt-II) (3.14 Min/3.6 Nom
mm thickness)
• Insulation screen (0.6 mm thick)
• Conductors for insulated electric cables and flexible cords - IS:8130
and IS:398
• Copper tape (Min. 0.1 mm thick)( very important- at chimmony the size is .045mm)
• Outer PVC sheath Type ST-7(1.4 Min/2.0 Nom mm thick)-IS: 5831
• Process for both conductor screen and insulation screen which is
semi-conducting compound are extruded and are applied along with
XLPE insulation in a single operation by ‘triple extrusion’ process.
Method of curing is dry curing
More discussion can be downloaded.
Design and construction
Messanger
Conductor
a)Aluminum Alloy, Aluminum Conductor, Aluminum Conductor Steel Reinforced
b) Insulation: PVC
11KV ABC Cable:
a) Conductor: Hard Drawn Aluminum
b) Conductor Screen: Semi-Conductive Compound
c) Insulation: Cross-Linked Polyethylene
d) Insulation Screen: Sem-conductive Compound
e) Metallic Screen: Copper Tape
f) Outer Sheath: Black PVC + Ultra Violet Resistant
Semi conducting Layer
The material is a polymer base mixed with a conductivity imparting agents such as carbon black.
Semi-conducting compounds also have the effect of fillings in the interstices of the conductor giving a smooth surface for insulation.
semiconductor behaves as conductors when temperature rises so when the HT cables is on load , Its conductor temperature rises due to this the semicon layer which is on conductor behaves like conductor as a result overall cross-section area is increased
The second silicon layer which is over XLPE on temperature rise behaves a conductor and used for dissipating heat out of conductor as the cable heat due to load. The semi-conductive layer also serves to even out the stresses associated with partial discharge which would otherwise attack the insulation at specific points.
It acts a smooth transition between each layers
It protects XLPE insulation from moisture abosrption.
components of HV ABC
Stranded Aluminium round Phase conductor - IS: 398
• Conductor screen of semiconducting compound (0.5 mm thick)
• Polyethylene (XLPE) Insulation - IS:7098 (Pt-II) (3.14 Min/3.6 Nom
mm thickness)
• Insulation screen (0.6 mm thick)
• Conductors for insulated electric cables and flexible cords - IS:8130
and IS:398
• Copper tape (Min. 0.1 mm thick)( very important- at chimmony the size is .045mm)
• Outer PVC sheath Type ST-7(1.4 Min/2.0 Nom mm thick)-IS: 5831
• Process for both conductor screen and insulation screen which is
semi-conducting compound are extruded and are applied along with
XLPE insulation in a single operation by ‘triple extrusion’ process.
Method of curing is dry curing
More discussion can be downloaded.