Method of manufacturing a polymer-insulated conductor

1. A method of manufacturing a polymer-insulated conductor, wherein the method comprises:

a) providing a conductor having a first cross-sectional shape,

b) passing the conductor through a conductor-shaping die to shape the conductor such that the conductor obtains a second cross-sectional shape, wherein frictional heat is developed in the conductor, thereby setting the conductor in a heated state,

c) applying molten polymer to the conductor when the conductor is in the heated state to obtain a polymer-coated conductor, and

d) shaping the polymer-coated conductor by passing the polymer-coated conductor through a polymer-shaping die to thereby obtain the polymer-insulated conductor.

2. The method as claimed in claim 1 , wherein the conductor-shaping die is adapted to shape the conductor to a rectangular cross section with rounded corners.

3. The method as claimed in claim 2 , wherein the polymer-shaping die is adapted to shape the polymer of the polymer-coated conductor to a rectangular cross section with rounded corners that have radii smaller than radii of the rounded corners of the conductor.

4. The method as claimed in claim 3 , wherein corners of the polymer-insulated conductor are essentially right angled.

5. The method as claimed in claim 3 , wherein a ratio of a radius of a corner of the conductor and a radius of a corner of the polymer-insulated conductor is in the range 1:0.9 to 1:0.1.

6. The method as claimed in claim 2 , wherein the polymer-shaping die is adapted to shape the polymer-coated conductor to a rectangular cross section with rounded corners.

7. The method as claimed in claim 1 , wherein the polymer-shaping die is adapted to shape the polymer-coated conductor to a rectangular cross section with rounded corners.

8. The method as claimed in claim 1 , wherein the polymer-shaping die is an extrusion die.

9. The method as claimed in claim 1 , wherein the molten polymer is one of a thermoplastic, a thermoplastic elastomer, a fluoroelastomer, and an epoxy thermoplastic blend.

10. The method as claimed in claim 1 , wherein the conductor-shaping die has a die opening with a first center and the polymer-shaping die has a die opening with a second center, wherein the first center is aligned with the second center.

11. The method as claimed in claim 10 , wherein a cross-sectional shape of the die opening of the conductor-shaping die differs from a cross-sectional shape of the die opening of the polymer-shaping die.

12. The method as claimed in claim 10 , wherein cross-sectional dimensions of the die opening of the conductor-shaping die are smaller than cross-sectional dimensions of the conductor.

13. The method as claimed in claim 1 , wherein the polymer-insulated conductor is a high voltage conductor.

14. The method as claimed in claim 1 , wherein the polymer-insulated conductor is a medium voltage conductor.

15. The method as claimed in claim 1 , further comprising cooling the conductor with a cooling unit after the conductor passes through the conductor-shaping die but before applying the molten polymer to the conductor.

16. The method as claimed in claim 15 , wherein the cooling unit cools the conductor without the conductor reaching a steady state temperature.

17. The method as claimed in claim 1 , using the frictional heat resulting from passing the conductor through the conductor-shaping die to melt polymer pellets or polymer powder into the molten polymer that is to be applied to the conductor.

18. The method as claimed in claim 17 , further comprising using a heat exchanging device to transport the frictional heat from the conductor to a polymer application device which melts the polymer pellets or the polymer powder and applies the molten polymer to the conductor.