Medium voltage
Medium voltage cables normally refers to those carrying voltages from 3.3 KV to 33 KV. AEI Compounds started making sioplas medium voltage compounds in 1977 and as such our products have been in service for 30 years.
A medium voltage insulated conductor consists of a layer of insulation between layers of semi-conducting compound. The semi-conducting layers are there to even out electrical stresses and can be fully bondable or strippable. We provide all of the components necessary to produce medium voltage cables both for power cable and flexible applications such as festoon cable for cranes and mobile equipment.
The thickness of the insulation determines the operating voltage, for sioplas compounds this is 3.4mm for 10KV rising to 10mm for 30KV. All three layers can be extruded together through a three layer head and the cooling is carried out in a graduated water bath to avoid the formation of voids. Curing is carried out in hot water or a steam chamber.
Cable type
Insulation thickness (mm)
Cure time (days)
80oC
90oC
11 KV
3.4
2
1
22 KV
5
5
3
33 KV
8
10
5
The use of sioplas materials has several advantages over continuous vulcansiation (CV) peroxide curable routes. Sioplas is finding new popularity in this sector principally because it is a low cost route to get started or expand existing operations. Other advantages are:-
- lower capital investment
- extruder speed faster for 11 and 22 kV with less chance of scorch
- line speed quicker due to time required to x-link in CV tube
- more flexibility with production schedules etc
- less difficulty in starting and stopping
- energy costs lower
- lower scrap rates
Medium voltage and high voltage compounds are now being specified with HFFR sheaths and for this application a tough material is needed to ensure minimal damage during handling. In this case TP521 is an ideal choice, particularly with its good crack resistance, important when sheathing compounds are laid over armour wires.
Grades available
|
Density |
Tensile |
Elongation |
Volume |
Dielectric |
Power |
Permittivity |
Data |
| SX409:CM401 Silane crosslinkable polyethylene (XLPE) insulation for up to 36kV | |||||||
|
0.928 |
18 |
350 |
>1x1016 |
21 |
0.0004 |
2.5 |
|
|
SX409NT:CM401 Tree retardant silane crosslinkable polyethylene (XLPE) insulation for up to 36kV |
|||||||
|
0.928 |
18 |
350 |
>1x1016 |
21 |
0.0004 |
2.5 |
|
| SX505:CM493 Flexible silane crosslinkable EPR insualtion for up to 36kV | |||||||
|
0.90 |
9 |
350 |
1x1016 |
- |
0.0016 |
2.29 |
|
| SX505:CM493 Flexible silane crosslinkable EPR insualtion for up to 36kV | |||||||
|
0.90 |
9 |
350 |
1x1016 |
- |
0.0016 |
2.29 |
|
| SX554:CM493 Very flexible silane crosslinkable EPR insualtion for up to 20kV | |||||||
|
0.90 |
9 |
420 |
>1x1016 |
- |
0.0016 |
2.29 |
|
|
SX539 Semi-conducting silane crosslinkable (XLPE) fully bondable screen |
|||||||
|
1.160 |
13 |
150 |
<102 |
- |
- |
- |
|
| SX528 Semi-conducting silane crosslinkable (XLPE) strippable screen | |||||||
| 1.15 | 7 | 300 |
<103 |
- | - | - |
|
| TP521 Tough thermoplastic Halogen free flame retardant sheath | |||||||
|
1.50 |
13 |
160 |
- |
- |
- |
- |
|
Please note that all of the silane crosslinkable grades are shown as a system with a graft and a catalyst. These are normally used in the ratio of 95:5. The most common catalyst masterbatch is shown in the table but there are others available which helps us to more accurately match your property requirements and processing conditions.
