Rotor blade for a wind turbine
A rotor blade for a wind turbine includes a blade skin forming a suction surface and a pressure surface. An electric heating arrangement has a heating strip with a width-thickness relation configured to reduce bonding between ice and the blade skin by electrically heating a respective surface of the blade skin and to conduct lightning-strike currents of at least 10 kA. An energy transfer arrangement supplies electrical energy to the heating arrangement. An integrated lightning arrangement includes a lightning receptor mounted to a tip section of the blade and electrically connected to the heating strip such that the lightning strike is conducted from the lightning receptor to the heating strip. A grounding device is connected to a grounding arrangement of the wind turbine such that electrical energy of the lightning strike is conducted from the heating strip through the grounding device and into the grounding arrangement.
1. A rotor blade for a wind turbine, comprising:
a root section having a blade root; a tip section having a blade tip;
a middle section between the root section and the tip section;
a blade skin forming a suction surface and a pressure surface of the rotor blade;
an electric heating arrangement comprising at least one heating strip having a width-thickness relation configured to reduce an adhesive bonding between ice and the blade skin by electrically heating a respective surface of the blade skin and to conduct lightning-caused currents of at least 10 kA;
an energy transfer arrangement electrically connected to the heating arrangement to supply electrical energy to the heating arrangement; and
an integrated lightning arrangement, comprising:
a lightning receptor mounted to the tip section and electrically connected to the heating strip such that a totality of electrical energy of a lightning strike is conducted from the lightning receptor to the heating strip; and
a grounding device mounted to or in the root section and electrically connected to a grounding arrangement of the wind turbine such that electrical energy of a lightning strike is conducted from the heating strip through the grounding device and into the grounding arrangement.
2. The rotor blade according to claim 1 , wherein the at least one heating strip has a width-thickness relation of at least 50:1.
3. The rotor blade according to claim 1 , wherein the at least one heating strip extends over 50% of a total length of the rotor blade in a longitudinal direction of the rotor blade.
4. The rotor blade according to claim 1 , wherein the heating arrangement comprises a heating loop having two of the heating strips connected to each other in the tip section, each of the heating strips having a root portion arranged in the root section, at least one of the root portions electrically connected to the energy transfer arrangement.
5. The rotor blade according to claim 1 , wherein the at least one heating strip is laminated within the blade skin.
6. The rotor blade according to claim 1 , wherein the heating arrangement is configured to introduce at least 10 kW of heat energy into the blade skin, wherein the heat energy exceeds 0.1 kW/m 2 and is not more than 20 kW/m 2 of the surface of the blade skin.
7. The rotor blade according to claim 1 , wherein the at least one heating strip is laminated within the blade skin comprises one of: a continuous solid material, a plurality of electrically connected sub-strips, a mesh ribbon, or a woven matt.
8. The rotor blade according to claim 1 , wherein the at least one heating strip is made from copper or a copper alloy having a purity of more than 80%.
9. The rotor blade according to claim 1 , wherein the heating arrangement ( 200 ) comprises an even number of the heating strips formed into respective loops of two of the heating strips per loop.
10. The rotor blade according to claim 1 , wherein the at least one heating strip comprises a plurality of parallel aligned single conductors not exceeding 50 of the single conductors.
11. A rotor of a wind turbine, comprising:
a rotatable hub;
at least one rotor blade according to the rotor blade of claim 1 rotatably mounted to the hub; and
the hub comprising a pitch assembly that rotates the rotor blade about a pitch axis.
12. The rotor according to claim 11 , wherein the energy transfer arrangement comprises a transformer device having a blade transformer portion mounted to the root section and electrically connected to the heating arrangement and a hub transformer portion mounted to the hub, wherein the transformer device provides contactless transmission of electrical energy from the hub transformer portion to the blade transformer portion.
13. A wind turbine, comprising:
a rotor, the rotor further comprising a rotatable hub;
at least one rotor blade according to the rotor blade of claim 1 rotatably mounted to the hub; and
the hub comprising a pitch assembly that rotates the rotor blade about a pitch axis.
14. A rotor blade for a wind turbine, comprising:
a root section having a blade root; a tip section having a blade tip;
a middle section between the root section and the tip section;
a blade skin forming a suction surface and a pressure surface of the rotor blade;
an electric heating arrangement comprising at least one heating strip having a width-thickness relation configured to reduce an adhesive bonding between ice and the blade skin by electrically heating a respective surface of the blade skin and to conduct lightning-caused currents of at least 10 kA;
an energy transfer arrangement electrically connected to the heating arrangement to supply electrical energy to the heating arrangement;
an integrated lightning arrangement, comprising:
a lightning receptor mounted to the tip section and electrically connected to the heating strip such that electrical energy of a lightning strike is conducted from the lightning receptor to the heating strip;
a grounding device mounted to or in the root section and electrically connected to a grounding arrangement of the wind turbine such that electrical energy of a lightning strike is conducted from the heating strip through the grounding device and into the grounding arrangement; and
wherein the heating arrangement has an overall resistance of at least 0.1 ohm and not more than 1 ohm.
15. A rotor blade for a wind turbine, comprising:
a root section having a blade root; a tip section having a blade tip;
a middle section between the root section and the tip section;
a blade skin forming a suction surface and a pressure surface of the rotor blade;
an electric heating arrangement comprising at least one heating strip having a width-thickness relation configured to reduce an adhesive bonding between ice and the blade skin by electrically heating a respective surface of the blade skin and to conduct lightning-caused currents of at least 10 kA;
an energy transfer arrangement electrically connected to the heating arrangement to supply electrical energy to the heating arrangement;
an integrated lightning arrangement, comprising:
a lightning receptor mounted to the tip section and electrically connected to the heating strip such that electrical energy of a lightning strike is conducted from the lightning receptor to the heating strip;
a grounding device mounted to or in the root section and electrically connected to a grounding arrangement of the wind turbine such that electrical energy of a lightning strike is conducted from the heating strip through the grounding device and into the grounding arrangement; and
wherein the energy transfer arrangement comprises a transformer device having a blade transformer portion mounted to the root section and electrically connected to the heating arrangement and a hub transformer portion mounted to a rotor hub of a rotor of the wind turbine, wherein the transformer device provides contactless transmission of electrical energy from the hub transformer portion to the blade transformer portion.