Scavenging concept for a hydrogen cooled generator

1. A hydrogen cooled generator assembly comprising:

a hydrogen cooled generator;

a fundament, wherein the generator is mounted on the fundament, and wherein the fundament includes at least one cavity underneath the generator, the at least one cavity being defined by a plurality of cavity walls;

at least one terminal box disposed in the cavity and adjacent to the generator and extending downward from the generator for collection of a plurality of electrical links from the generator;

at least one collection box disposed in the cavity and essentially beneath the at least one terminal box having a top terminal box wall and first and second side terminal box walls and configured to guide the plurality of electrical links from the at least one terminal box in a further downward direction, wherein the plurality of electrical links enters the at least one collection box through the top terminal box wall, and wherein cooling air is configured to flow into the at least one collection box and configured to leave through the top terminal box wall;

a lateral space defined by the first side terminal box wall, the second side terminal box wall, the plurality of cavity walls; and

a seal plate delimiting the lateral space at an upper end of the lateral space.

2. The hydrogen cooled generator assembly as recited in claim 1 , wherein an edge of the seal plate borders the at least one collection box and the seal plate is disposed at the same height as or not more than 50 cm below the top wall.

3. The hydrogen cooled generator assembly as recited in claim 1 , wherein the seal plate is disposed horizontally.

4. The hydrogen cooled generator assembly as recited in claim 1 , wherein the seal plate one of includes an electrically insulating.

5. The hydrogen cooled generator assembly as recited in claim 4 , wherein the electrically insulating material is a glass fibre reinforced polymer material selected from epoxy-based polymer materials.

6. The hydrogen cooled generator assembly as recited in claim 1 , wherein the seal plate does not completely seal the lateral space from a space above the seal plate so as to allow 5-15% of the cooling air to enter the lateral space.

7. The hydrogen cooled generator assembly as recited in claim 6 , wherein the seal plate includes openings configured to enable entry to the lateral space from above.

8. The hydrogen cooled generator assembly as recited in claim 1 , wherein the first terminal box side wall, the second terminal box side wall, are distanced from the plurality of cavity walls in an axial and in a lateral direction relative to a main axis of the generator by at least 50 cm, and wherein the seal plate covers a whole periphery of the lateral space surrounding the at least one collection box in the lateral direction.

9. The hydrogen cooled generator assembly as recited in claim 1 , wherein each one of the plurality of electrical links are guided in each one of a plurality of columnar structures from the at least one terminal box in a downward direction and through the at least one collection box, wherein the top wall includes a plurality of tubular structures extending from the top wall towards the at least one terminal box, each one of the plurality of tubular structures corresponding to each one of the plurality of electrical links and having an inner diameter larger than an outer diameter of a corresponding electrical link, and wherein each one of the plurality of tubular structures is open towards an interior of the at least one collection box and open towards a top edge of the tubular structure.

10. The hydrogen cooled generator assembly as recited in claim 9 , wherein the plurality of electrical links includes at least three electrical links.

11. The hydrogen cooled generator assembly as recited in claim 10 , wherein the top edge of the tubular structure is distanced from a bottom wall of the terminal box by at least 10 cm.

12. The hydrogen cooled generator assembly as recited in claim 9 , wherein an axis of each one of the plurality of tubular structures is collinear with an axis of the corresponding electrical link.

13. The hydrogen cooled generator assembly as recited in claim 9 , wherein the inner diameter of each of the plurality of tubular structures is at least a factor 2 larger than an outer diameter of the corresponding electrical link.

14. The hydrogen cooled generator assembly as recited in claim 9 , wherein the outer diameter of each one of the plurality of electrical links is in a range of 5 mm-20 mm, and wherein the inner diameter of each one of the plurality of tubular structures is in a range of 20 mm-100 mm.

15. The hydrogen cooled generator assembly as recited in claim 14 , wherein the outer diameter of each one of the plurality of electrical links is in a range of 5 mm-15 mm, and wherein the inner diameter of each one of the plurality of tubular structures is in a range of 30 mm-60 mm.

16. The hydrogen cooled generator assembly as recited in claim 9 , wherein at least one of the plurality of tubular structures includes at least one ring winding configured to measure the current in a corresponding electrical link.

17. The hydrogen cooled generator assembly as recited in claim 16 , wherein the cooling air is configured to travel through each one of the plurality of tubular structures from the at least collection box so as to cool the at least one ring winding.

18. The hydrogen cooled generator assembly as recited in claim 1 , wherein the at least one terminal box and the at least one collection box are disposed at each axial end of the generator, and wherein at least one ventilator is disposed in the fundament or outside of the fundament for the aspiration of outside air, and wherein cooling air propelled by the at least one ventilator is configured to be channelled through cooling air piping to a bottom part of the at least one collection box.

19. A method for scavenging the bottom part of a hydrogen cooled generator, wherein the hydrogen cooled generator is mounted on a fundament, and wherein the fundament includes at least one cavity underneath the generator, the at least one cavity including a first and a second vertical wall; at least one terminal box disposed adjacent to the generator and extending downward from the generator for collection of a plurality of electrical links from the generator; at least one collection box disposed beneath the at least one terminal box having a top wall and a first and a second side wall and configured to guide the plurality of electrical links from the at least one terminal box in a further downward direction, wherein the plurality of electrical links enters the at least one collection box through the top wall, and wherein cooling air is configured to flow into the at least one collection box and configured to leave through the top wall; a lateral space defined by the first side wall, the second side wall, the first vertical wall and the second vertical wall; and a seal plate covering the lateral space at an upper end of the lateral space, the method comprising:

forcing externally provided cooling air into the at least one collection box;

allowing the cooling air to leave the at least one collection box through the top wall; and

allowing the cooling air to travel through a space surrounding the generator and to leave the space towards a top part of the space.

20. The method as recited in claim 19 , wherein the air flow is in a range of 10,000-30,000 m 3 /h/terminal measured at standard temperature and pressure.