Wind turbine rotor blade having an electrical heating device and a plurality of lightning conductors

1. A wind turbine rotor blade comprising:

a rotor blade root;

a rotor blade tip;

an electrical heating device;

a first lightning receptor disposed in the region of the rotor blade tip;

at least but not more than two lightning conductors leading from said first lightning receptor to said rotor blade root;

a second lightning receptor arranged at a distance to said rotor blade tip and connected to only one of said lightning conductors; and,

each one of said two lightning conductors being electrically conductively connected to said electrical heating device at a multiplicity of points between said rotor blade root and said rotor blade tip so as to cause equipotential bonding between said two lightning conductors via said electrical heating device in response to a lightning strike to said rotor blade.

2. The wind turbine rotor blade of claim 1 , wherein each of said two lightning conductors is in electrical contact to said electrical heating device along the entire length of said electrical heating device.

3. The wind turbine rotor blade of claim 1 , wherein said electrical heating device is configured to be supplied with heating current via said two lightning conductors.

4. The wind turbine rotor blade of claim 3 , wherein the rotor blade defines a longitudinal direction and said heating device is configured such that said heating current supplied to said heating device via said two lightning conductors flows transverse to said longitudinal direction.

5. The wind turbine rotor blade of claim 1 , wherein said heating device has a predetermined length; and, one of said lightning conductors includes a metallic conductor extending over the entirety of said predetermined length of said heating device.

6. The wind turbine rotor blade of claim 1 , wherein the heating device has a predetermined length, the wind turbine rotor blade further comprising:

an electrically conductive main spar cap extending over all of said predetermined length of said heating device; and,

at least one of said two lightning conductors is at least partially defined by said electrically conductive main spar cap.

7. The wind turbine rotor blade of claim 6 further comprising:

an electrically insulating layer;

the wind turbine rotor blade defining an aerodynamic surface and a longitudinal direction;

said main spar cap having an outer side facing said aerodynamic surface;

said outer side having a first section extending in the form of a strip in said longitudinal direction;

said first section being in electrical contact with said heating device; and,

said outer side further having a second section separated from said heating device by said electrically insulating layer.

8. The wind turbine rotor blade of claim 6 , wherein:

a first one of said two lightning conductors includes a metallic conductor arranged adjacent to said main spar cap; and,

said first one of said two lightning conductors is, in the region of the heating device, formed by said main spar cap and said metallic conductor.

9. The wind turbine rotor blade of claim 8 further comprising a metallic grid arranged between said main spar cap and said metallic conductor.

10. The wind turbine rotor blade of claim 1 , wherein said heating device includes carbon fiber material.

11. The wind turbine rotor blade of claim 1 further comprising a ground terminal in the region of said rotor blade root; a connection between one of said two lightning conductors and at least one of said first lightning receptor, said second lightning receptor and said ground terminal; and, said connection having at least one of a spark gap and a vacuum interrupter.

12. The wind turbine rotor blade of claim 1 , wherein:

the wind turbine rotor blade has a pressure side and a suction side; and,

one of said first and second lightning conductors is arranged on said pressure side and the other one of said first and second lightning conductors is arranged on said suction side of said wind turbine rotor blade.

13. The wind turbine rotor blade of claim 1 , wherein:

the wind turbine rotor blade has a pressure side and a suction side; and,

said wind turbine rotor blade comprises third and fourth lightning receptors mounted on said pressure and suction sides, respectively.

14. The wind turbine rotor blade of claim 13 , wherein:

the wind turbine rotor blade has a predetermined length; and,

said lightning receptors are arranged at a distance of at most 20% of said predetermined length away from said rotor blade tip.