Ligthning protection system

A wind turbine blade comprising:

• a root end;
• a tip end;
• a longitudinal axis;
• a pressure side;
• a suction side, wherein the pressure side and the suction side are outer faces of the wind turbine blade;
• a structural element extending along the longitudinal axis, where the structural element is a spar or beam made of carbon fiber reinforced polymer (CFRP) being electrically conductive;
• and
• a lightning protection system comprising:
• a first down conductor extending from the tip end to a tip connection block arranged at a predetermined distance from the tip end, the first down conductor being electrically connected with the tip connection block;
• a second down conductor extending from the tip connection block between and along the structural element and the pressure side towards a root connection block arranged at the root end;
• a third down conductor extending from the tip connection block between and along the structural element and the suction side towards the root connection block;
• the second down conductor comprises a first expanded foil or a first mesh and the third down conductor comprises a second expanded foil or a second mesh, the first expanded foil or the first mesh and the second expanded foil or the second mesh are made of a conductive material;
• and
• the first expanded foil or the first mesh and the second expanded foil or the second mesh comprise a plurality of conductive connection points, the plurality of conductive connection points are arranged in the vicinity of the tip connection block and the root connection block and are electrically connected with the tip connection-block and the root connection block, respectively.

A wind turbine comprising:

• a wind turbine blade comprising:
• a root end;
• a tip end;
• a longitudinal axis;
• a pressure side;
• a suction side, wherein the pressure side and the suction side are outer faces of the wind turbine blade;
• a structural element extending along the longitudinal axis, where the structural element is a spar or beam made of carbon fiber reinforced polymer (CFRP) being electrically conductive;
• and
• a lightning protection system comprising:
• a first down conductor extending from the tip end to a tip connection block arranged at a predetermined distance from the tip end, the first down conductor being electrically connected with the tip connection block;
• a second down conductor extending from the tip connection block between and along the structural element and the pressure side towards a root connection block arranged at the root end;
• a third down conductor extending from the tip connection block between and along the structural element and the suction side towards the root connection block;
• the second down conductor comprises a first expanded foil or a first mesh and the third down conductor comprises a second expanded foil or a second mesh, the first expanded foil or the first mesh and the second expanded foil or the second mesh are made of a conductive material;
• and
• the first expanded foil or the first mesh and the second expanded foil or the second mesh comprise a plurality of conductive connection points, the plurality of conductive connection points are arranged in the vicinity of the tip connection block and the root connection block and are electrically connected with the tip connection-block and the root connection block, respectively.

A method for providing a conductive connection point of a lightning protection system to an expanded foil or a mesh, wherein the lightning protection system comprises:

• a first down conductor extending from the tip end to a tip connection block arranged at a predetermined distance from the tip end, the first down conductor being electrically connected with the tip connection block;
• a second down conductor extending from the tip connection block between and along the structural element and the pressure side towards a root connection block arranged at the root end;
• a third down conductor extending from the tip connection block between and along the structural element and the suction side towards the root connection block;
• the second down conductor comprises a first expanded foil or a first mesh and the third down conductor comprises a second expanded foil or a second mesh, the first expanded foil or the first mesh and the second expanded foil or the second mesh are made of a conductive material;
• and
• the first expanded foil or the first mesh and the second expanded foil or the second mesh comprise a plurality of conductive connection points, the plurality of conductive connection points are arranged in the vicinity of the tip connection block and the root connection block and are electrically connected with the tip connection-block and the root connection block, respectively
• the method comprising
• melting a conductive material;
• applying the melted conductive material in a liquid state for surrounding the expanded foil or the mesh;
• allowing the melted conductive material to harden for providing a mechanical and electric conductive connection between the conductive connection point and the expanded foil or the mesh.

A method for providing a conductive connection point of a lightning protection system to an expanded foil or a mesh, wherein the lightning protection system comprises:

• a first down conductor extending from the tip end to a tip connection block arranged at a predetermined distance from the tip end, the first down conductor being electrically connected with the tip connection block;
• a second down conductor extending from the tip connection block between and along the structural element and the pressure side towards a root connection block arranged at the root end;
• a third down conductor extending from the tip connection block between and along the structural element and the suction side towards the root connection block;
• the second down conductor comprises a first expanded foil or a first mesh and the third down conductor comprises a second expanded foil or a second mesh, the first expanded foil or the first mesh and the second expanded foil or the second mesh are made of a conductive material;
• and
• the first expanded foil or the first mesh and the second expanded foil or the second mesh comprise a plurality of conductive connection points, the plurality of conductive connection points are arranged in the vicinity of the tip connection block and the root connection block and are electrically connected with the tip connection-block and the root connection block, respectively
• the method comprising:
• providing at least two discs being made of conductive material;
• arranging the at least two discs on opposite sides of the expanded foil or the mesh;
• fastening the at least two discs to each other with the expanded foil or the mesh between the at least two discs for providing an electric conductive connection between the at least two discs.