Conductors
Copper conductors are commonly used for home & light industrial applications
Aluminium conductors are optionally used by utilities for distribution & transmission
IEC 60228 Conductors of Insulated Cables
Class 1 : Solid Conductors
Class 2 : Stranded Conductors
Class 5 : Flexible Conductors
Class 6 : Flexible Conductors which are more flexible than class 5
Conductor Shapes
LV PVC/PVC Single Core Cable
1. Stranded circular non compacted conductor
2. PVC insulation
3. PVC sheath/jacket
LV XLPE Four Core Cable
1. Non hygroscopic filler
2. Stranded sectoral shaped compacted aluminium conductors
3. XLPE insulation
4. Binder tape
5. MDPE inner sheath
6. Copper tape
7. Separator tape
8. MDPE outer sheath
MV XLPE Single Core Cable
1. Stranded circular compacted copper or aluminium conductor
2. Extruded conductor screen
3. XLPE insulation
4. Insulation screen
5. Copper tape screen
6. MDPE Inner sheath
7. Separator tape
8. MDPE outer sheath
11kV XLPE Three Core Cable
1.Stranded circular compacted aluminium conductors
2. Conductor screen
3. XLPE insulation
4. Insulation screen
5. Phase identification coloured strip
6. Copper tape screen
7. Non hygroscopic polypropylene fillers
8. Binder tape
9. MDPE inner sheath
10. Separator tape
11. MDPE outer sheath
33kV XLPE Single Core Cable
1. Stranded circular compacted copper or aluminium conductor
2. Extruded conductor screen
3. XLPE insulation
4. Extruded insulation screen
5. Equipotential tape
6. Copper wire screen with equipotential copper tape
7. Semiconducting swellable tape
8. Laminated aluminium foil
9. MDPE outer sheath
PILC Cables
Electrical Test for cables
Non-Electrical Test for cables
Cable Testing for Maintenance
These on on-site tests are performed individually or in combination :
1. Before energizing a new equipment as a commissioning test;
2. after maintenance (or repair)
3. after network alteration.
Cable Maintenance Matrix
1. C COMMISSIONING : Newly installed cables prior to first energization
2. IS IN SERVICE : Condition based maintenance practice
3. AR AFTER REPAIR : After replacement of faulty section
Categorization of On site Tests
Destructive off line tests are “go / no go” tests;
Non destructive off line tests are diagnostic tests;
Non destructive on line tests are condition monitoring tests.
Field tests can be performed on cables during various stages of their existence.
IEEE 400 standard defines these tests as:
Installation Test
Acceptance Test
Maintenance Test
These cable field tests can be broadly divided in two main groups:
Tier 1 cable field tests are classified as follows:
Destructive off line “go / no go” tests Tier 1 Type 1: DC, Very Low Frequency and Power Frequency
Non destructive off line diagnostic tests Tier 1 Type 2: Insulation Resistance, PIDAR, Online PD Scanning
Tier 2 cable field tests are classified as follows:
Non destructive off line diagnostic tests Tier 2 Type 1: Offline PD Mapping, Tan Delta, Monitored Withstand Test
Non destructive on line tests Tier 2 Type 2: Short term or continuous PD monitoring
Insulation Resistance
Insulation Resistance Test Set-up
Insulation Resistance Testing Video
Surface Leakage Current
Insulation Resistance Testing (with Guard connection) Video
