66KV 110KV 127KV 132KV 145KV 220KV ultra-high voltage Copper conductor XLPE insulated metal armor Cable /ZMS Cable 2018

APPLICA:

 

APPLICATIONS:

The cables are designed for distribution of electrical power with nominal voltage Uo/U 19/33KV and frequency 50Hz. It is used to transmit and distribute power in power transmission and distribution system of 33kV or lower. It is generally applied to the fields including power, construction, mines, metallurgy, petrochemical industry and communication in complete replace of oil immersed paper insulated power cable and in partial replace of PVC insulated power cable.

STANDARD:

BS 6622

BS 7835 (LSZH Version)

CONSTRUCTION:

Conductor: Plain annealed copper or aluminium complying with IEC 60228/BS 6360. Copper

conductors shall be stranded and aluminium conductors shall be either solid or

stranded.

Conductor Screen: Extruded layer of semi-conducting cross-linkable compound is applied

over the conductor and shall cover the surface completely. The minimum thickness is 0.3mm

and the maximum resistivity shall not exceed 500 Ohm-m at 90°C.

Insulation: Insulation is of cross-linked polyethylene compound XLPE (GP8) conforming to

BS 7655-1.3 or EPR (GP7), conforming to BS 7655-1.2.

TABLE 1. INSULATION THICKNESS:

Insulaton Screen: Extruded layer of semi-conducting cross-linkable compound is applied

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.

Inner Covering; Fillers: For cables with a collective metallic layer or cables with a metallic

layer over each individual cores with additional collective metallic layers, semi-conducting

inner covering and fillers shall be applied over the laid up cores. The inner covering is made

of non hygroscopic material, except if the cable is to be made longitudinally watertight. The

inner covering shall be extruded or lapped.

The approximate thickness of extruded inner coverings is given in Table 2:

TABLE 2. APPROXIMATE THICKNESS OF EXTRUDED INNER COVERINGS

Metallic Layer: The metallic layer shall be applied over each core or applied as a collective

screen. The metallic screen shall consist of either copper tapes or a concentric layer of

copper wires or a combination of tapes and wires. The metallic layer provides an earth

fault current path, capable of withstanding fault current to earth of 1000A for one second at

maximum temperature 160°C. Copper wires are applied over the conducting water blocking

layer with a minimum diameter of 0.5mm. And over the copper wires, copper tape with

minimum thickness of 0.1mm can be applied helically with overlap.

Total cross section of copper wire screen is shown in table 3.

TABLE 3. MINIMUM TOTAL CROSS SECTION OF COPPER WIRE SCREEN; DC RESISTANCE OF THE SCREEN

Separation Sheath (for armoured cable): The separation sheath comprises a layer of extruded PVC, PE or LSZH. The nominal thickness is calculated by 0.02Du + 0.6mm where Du is the fictitious diameter under the sheath in mm. The nominal separation sheath thickness

shall not be less than 1.2mm.

Armour (for armoured cable): The armour consists of galvanized steel wire applied over the

inner covering with diameter specified as in Table 4.

TABLE 4. ARMOUR WIRE DIAMETER

Over Sheath: Overall sheath comprises a layer of extruded either PVC type 9 conforming

to BS 7665-4.2 or MDPE type TS2 conforming to BS 7655-10.1; LSZH can be offered as an

option. The over sheath is normally black in colour. When a DC voltage test is to be performed on the over sheath, a semi-conducting layer such as graphite coating shall be applied over the surface of the extruded over sheath. The nominal over sheath thickness is calculated by 0.035D+1 where D is the diameter immediately under the over sheath in mm. For cables with the over sheath not applied over the armour, the nominal over sheath thickness shall not be less than 1.4mm. And for cables with over sheath applied over the armour, the nominal over sheath thickness shall not be less than 1.8mm.

PHYSICAL PROPERTIES:

Operating Temperature: up to 90°C

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

Short Circuit Temperature: 250°C (short circuit duration up to 5 seconds)

Bending Radius: 12 x OD