Lightning protection system for wind turbine blades with conducting structural components

1. Lightning protection system of a wind turbine blade ( 10 ), whose structure comprises two structural shells ( 11 , 13 ) including two caps ( 19 , 21 ) formed by carbon fiber laminates and two spars ( 15 , 17 ), comprising:

a first subsystem comprising one or more lightning receptors ( 25 , 25 ′) connected to a first conductor cable ( 41 ) disposed inside of the wind turbine blade ( 10 ) for driving lightning to ground;

a second subsystem comprising connecting means between the caps ( 19 , 21 ) and the first conductor cable ( 41 ) allowing equipotentializing the lightning protection system in at least two cross sections ( 22 , 23 ) of the wind turbine blade ( 10 );

characterized in that:

the second subsystem also comprises in each of said cross sections ( 22 , 23 ) a first lateral lightning receptor ( 31 ) arranged on one edge of said cross sections ( 22 , 23 ) including first internal conducting blocks ( 36 , 37 ) in the structural shells ( 11 , 13 ) and first external connectors ( 56 , 57 ) configured so that they can interconnect electrically the first internal conducting blocks ( 36 , 37 );

the first internal conducting blocks ( 36 , 37 ) are connected to the caps ( 19 , 21 ) by first auxiliary cables ( 46 , 47 );

the first conductor cable ( 41 ) is connected to one of the first auxiliary cables ( 46 , 47 ) via a second auxiliary cable ( 53 ).

2. Lightning protection system according to claim 1 , wherein the terminals of the caps ( 19 , 21 ) to which said first auxiliary cables ( 46 , 47 ) are connected are metal plates.

3. Lightning protection system according to claim 1 , wherein the first lightning conductor cable ( 41 ) is attached to one of the spars ( 15 , 17 ) of the wind turbine blade ( 10 ).

4. Lightning protection system according to claim 1 , wherein one of the first external connectors ( 56 , 57 ) is dimensioned to contact with the first internal conducting blocks ( 36 , 37 ).

5. Lightning protection system according to claim 1 , wherein:

the first subsystem further comprises a second conductor cable ( 43 ) arranged inside of the wind turbine blade ( 10 ) for driving lightning to ground;

the second subsystem further comprises in each of said cross sections ( 22 , 23 ) a second lateral lightning receptor ( 30 ) arranged at the edge of said cross sections opposite to the edge of the first lateral lightning receptor ( 31 ) that includes second internal conducting blocks ( 34 , 35 ) in the structural shells ( 11 , 13 ) and second external connectors ( 54 ; 55 ) configured so that they allow to interconnect electrically the second internal conducting blocks ( 34 , 35 );

the second internal conducting blocks ( 34 , 35 ) are connected to the caps ( 19 , 21 ) by third auxiliary cables ( 44 , 45 );

the second conductor cable ( 43 ) is connected to one of said third auxiliary cables ( 44 , 45 ) by a fourth auxiliary cable ( 53 );

the second subsystem further comprises an equipotential bar ( 50 ) connected to the first and second conductor cables ( 41 , 43 ).

6. System according to claim 5 , wherein the terminals of caps ( 19 , 21 ) to which said third auxiliary cables ( 44 , 45 ) are connected are metal plates.

7. System according to claim 5 , wherein the second conductor cable ( 43 ) is attached to the one of the spars ( 15 , 17 ) of the wind turbine blade ( 10 ) to which is not attached the first lightning conductor cable ( 41 ).

8. Method of installing a lightning protection system according to claim 1 in a wind turbine blade ( 10 ) whose structure comprises two structural shells ( 11 , 13 ) including two caps ( 19 , 21 ) formed by carbon fiber laminates and two spars ( 15 , 17 );

the manufacturing process of the wind turbine blade ( 10 ) comprising a first stage of manufacturing said caps ( 19 , 21 ), a second stage of manufacturing the structural shells ( 11 , 13 ) with said caps ( 19 , 21 ) embedded therein; a third stage of joining the spars ( 15 , 17 ) to the lower structural shell ( 13 ) and a fourth stage of joining the two structural shells ( 11 , 13 );

characterized by comprising the following steps:

a) including conducting terminals in the caps ( 19 , 21 ) in the first stage;

b) mounting in each of said cross sections ( 22 , 23 ) the first internal conducting blocks ( 36 , 37 ) of the first lateral lightning receptor ( 31 ) during the second stage and after it connect them to the caps ( 19 , 21 ) by the first auxiliary cables ( 46 , 47 );

c) attaching the first conductor cable ( 41 ) to the spar ( 17 ) closest to the first lateral lightning receptor ( 31 ) and connect it to the first auxiliary cable ( 47 ) through the second auxiliary cable ( 51 ) in the third stage;

d) interconnect the first internal conducting blocks ( 36 , 37 ) by means of the first external connectors ( 56 , 57 ) in the fourth stage.

9. Method of installing a lightning protection system according to claim 5 in a wind turbine blade ( 10 ) whose structure comprises two structural shells ( 11 , 13 ) including two caps ( 19 , 21 ) formed by carbon fiber laminates and two spars ( 15 , 17 );

the manufacturing process of the wind turbine blade ( 10 ) comprising a first stage of manufacturing said caps ( 19 , 21 ), a second stage of manufacturing the structural shells ( 11 , 13 ) with said caps embedded therein, a third step of joining the spars ( 15 , 17 ) to the lower shell ( 13 ) and a fourth step of joining the two structural shells ( 11 , 13 );

characterized by comprising the following steps:

a) including conductive terminals in the caps ( 19 , 21 ) in the first stage;

b) mounting in each of said cross sections ( 22 , 23 ) the first and second internal conducting blocks ( 34 , 35 ; 36 , 37 ) of the first and second lateral lightning receptors ( 30 , 31 ) during the second stage and after it connecting them to the caps ( 19 , 21 ) through the first auxiliary cables ( 46 , 47 ) and the third auxiliary cables ( 44 , 45 );

c) attach the first and second conductor cables ( 41 , 43 ) to the spars ( 15 , 17 ), mounting the equipotential bar ( 20 ) between them and connect them, respectively, to the first and third auxiliary cable ( 47 , 45 ) by the second and fourth auxiliary cable ( 51 , 53 ) in the third stage;

d) interconnect the first and second internal conducting blocks ( 36 , 37 ; 34 , 35 ) through the first and second external connectors ( 56 , 57 ; 54 , 55 ) in the fourth stage.