Application

The single core cables are designed for distribution of electrical power with nominal voltage Uo/U ranging from 1.8/3KV to 18/30KV and frequency 50Hz. They are suitable for installation mostly in power supply stations, indoors and in cable ducts, outdoors, underground and in water as well as for installation on cable trays for industries, switchboards and power stations.

Standards

IEC 60502 Part 1(1.8/3KV)

IEC 60502 Part 2(3.6/6KV to 18/30KV)

Construction

Conductor : Plain annealed copper or aluminium complying with IEC 60228 class 1 or 2.

Conductor Screen : The conductor screen consists of an extruded layer of non metallic, semi-conducting compound firmly bonded to the insulation to exclude all air voids. The conductor screen is not necessary for both PVC and EPR/HEPR insulated 1.8/3KV and 3.6/6KV cables.

Insulation : Insulation is of polyvinyl chloride (PVC) intended for 1.8/3KV and 3.6/6KV cables, cross-linked polyethylene compound (XLPE) or ethylene propylene rubber (EPR/HEPR).

Table 1. Insulation Thickness of XLPE or EPR/HEPR Insulation

*Insulation Thickness of PVC is 3.4mm (1- 1600mm sq) for 3.6/6KV cables.

Insulaton Screen : The insulation screen consists of an extruded layer of non metallic, semiconducting compound extruded over the insulation. The extruded semi-conducting layer shall consist of bonded or cold strippable semi-conducting compound capable of removal for jointing or terminating. As an option, a semi-conducting tape may be applied over the extruded semi-conducting layer as a bedding for the metallic layer. The minimum thickness is 0.3 mm and the maximum resistivity is 500 Ohm-m at 90°C. The screen is tightly fitted to the insulation to exclude all air voids and can be easily hand stripped on site. The insulation screen is not necessary for both PVC and EPR/HEPR insulated 1.8/3KV and 3.6/6KV cables. The screen may be covered by semi-conductive water blocking swellable tape to ensure longitudinal watertightness.

Metallic Layer : The concentric copper screen wire is applied over the insulation, or over the insulation screen or over an inner covering. As an alternative, copper tape(s) with minimum thickness of 0.1mm can be applied with overlap. Total cross section of copper wire screen and copper tape screen layer are shown in Table 2a and 2b.

Table 2a. Total Cross Section and Max. DC Resistance of Copper Wire Screen

Table 2b. Total Cross Section and Max. DC Resistance of Copper Tape Screen (0.1mm)

Separation Sheath (for armoured cable) : The separation sheath comprises a layer of extruded PVC, PE or LSZH, applied under the armour. The nominal thickness is calculated by 0.02Du + 0.6mm where Du is the fictitious diameter under the sheath in mm. For cables without a lead sheath, the nominal separation sheath thickness shall not be less than 1.2mm. For cables where the separation sheath is applied over the lead sheath, the nominal separation sheath thickness shall not be less than 1.0mm.

Lapped Bedding (for armoured lead sheathed cable) : The lapped bedding consists of either impregnated/synthetic compounded paper tapes or a combination of two layers of these paper tapes followed by a few layers of compounded fabulous materials. The thickness is around 1.5mm.

Armour (for armoured cable) : The armour consists of round aluminium wire armour applied helically over an extruded separation sheath.

Table 3. Round Armour Wire Diameter

Over Sheath : Overall sheath comprises a layer of extruded thermoplastic compound (PVC, PE or LSZH can be offered as an option.) or elastomeric compound (polychlorprene CSP or chlorosulfonated PE). The nominal oversheath thickness is calculated by 0.035D+1 where D is the fictitiuous diameter immediately under the oversheath in mm. For unarmoured cables and cables with the oversheath not applied over the armour, metallic screen or concentric conductor, the nominal oversheath thickness shall not be less than 1.4mm. And for cables with oversheath applied over the armour, metallic screen or concentric conductor, the nominal oversheath thickness shall not be less than 1.8mm.

Physical Properties

Operating Temperature : up to 70°C (PVC insulation); up to 90°C (XLPE or EPR insulation)

Temperature Range : -5°C ( PVC or LSZH sheath ); -20°C ( PE sheath )

Short Circuit Temperature( 5 seconds maximum duration ) : 140-160°C (PVC insulation); 250°C (XLPE or EPR insulation)

Bending Radius : 20 x OD

Table 4. Nominal /Operating /Testing Voltages

*21/35KV and 26/35KV power frequency voltage test can be made under the following conditions: 2.5Uo x 30mins or 3.0Uo x 15mins. Numbers in brackets refer to the test values for 3.0Uo x 1.5mins.

Single Core 1.8/3KV (Um=3.6KV)

Dimensional Data

Electrical Data

Single Core 3.6/6KV (Um=7.2KV)

Dimensional Data

Electrical Data

* For capacitance & charging current values, multiply values shown by 1.2 for EPR insulated cables.

Single Core 6/10KV (Um=12KV)

Dimensional Data

Electrical Data

* For capacitance & charging current values, multiply values shown by 1.2 for EPR insulated cables.

Single Core 8.7/15KV (Um=17.5KV)

Dimensional Data

Electrical Data

* For capacitance & charging current values, multiply values shown by 1.2 for EPR insulated cables.

Single Core 12/20 V (Um=24KV)

Dimensional Data

Electrical Data

For capacitance & charging current values, multiply values shown by 1.2 for EPR insulated cables.

Single Core 18/30 V (Um=36KV)

Dimensional Data

Electrical Data

* For capacitance & charging current values, multiply values shown by 1.2 for EPR insulated cables.

Current Rating for Single Core 3.6/6KV(Um=7.2KV ) to 18/30KV(Um=36KV) XLPE Insulation

Current Rating for Single Core 3.6/6KV(Um=7.2KV ) to 18/30KV(Um=36KV) EPR Insulation

Current Rating Conditions

Ground Temperature : 20°C

Ambient Temperature (air) : 30°C

Depth of Soil : 0.8m

Thermal Resistance of Soil : 1.5K•m/W