Wind turbine electric filter comprising filter modules arranged at different platform heights inside a wind turbine tower

1. A wind turbine comprising:

a wind turbine rotor with a plurality of blades, the wind turbine rotor supported on a support structure that includes a wind turbine tower;

a generator operatively coupled to the wind turbine rotor;

a power electronic converter configured to convert electrical power generated by the generator to a converted AC power of predetermined frequency and voltage;

a main wind turbine transformer having a low voltage side and a high voltage side for transforming the converted AC power to a higher voltage; and

at least one electric filter connected to the high voltage side of the main transformer;

wherein the electric filter is arranged in the wind turbine tower;

wherein the electric filter comprises at least two filter modules, wherein a first module is arranged at a first platform within the wind turbine tower, and a second module is arranged at a second platform within the wind turbine tower;

wherein the first module comprises a reactor bank and a resistor bank connected in parallel, and the second module comprises a capacitor bank, the second module connected in series with the first module.

2. The wind turbine of claim 1 , wherein the electrical power generated by the generator has a plurality of electrical phases, and

the at least one electric filter comprises a plurality of electric filters;

wherein each of the electric filters is assigned to a respective one of the electrical phases.

3. The wind turbine of claim 1 , wherein each of the first and second platforms comprises a protective fence that defines a restricted area around a respective filter module of the first and second filter modules.

4. The wind turbine of claim 1 , wherein the first and second filter modules each further comprise a structural frame, and wherein each structural frame is attached to an inside wall of the wind turbine tower.

5. The wind turbine of claim 4 , wherein the inside wall of the wind turbine tower comprises a plurality of bosses and the structural frames are attached to the bosses.

6. The wind turbine of claim 1 , wherein the capacitor bank is connected to the high voltage side of the transformer.

7. The wind turbine of claim 1 , wherein the electric filter is connected to an electrical grid via a switchgear.

8. The wind turbine of claim 1 , wherein the wind turbine is an offshore wind turbine.

9. A wind farm comprising:

a substation with a common connection point;

two or more parallel wind farm strings connected to the common connection point, the wind farm strings each having a first end at or near the common connection point, a second end opposite the first end, and a plurality of wind turbines between the first end and the second end; and

wherein one or more of the wind farm strings comprise at least one wind turbine according to claim 1 .

10. The wind farm according to claim 9 , wherein each of the wind farm strings comprises at least one wind turbine according to claim 1 .

11. The wind farm according to claim 10 , wherein, for each of the wind farm strings, the at least one wind turbine according to claim 1 is arranged at or near the second end of the wind farm string.

12. The wind farm according to claim 9 , wherein the substation is configured to operate without a harmonic filter.