Method and a generator system for operating a generator

1. A method for operating a generator, the method comprising:

exciting a field winding of a rotor of the generator by a first exciter device;

driving a motor-driven second exciter device while operating the generator with the first exciter device; and

switching from the first exciter device to the second exciter device to excite the generator in a case where the first exciter device feeds to the generator insufficient energy for operating the generator during a malfunction of the first exciter device.

2. The method according to claim 1 , wherein the second exciter device operated next to the first exciter device comprises a motor-driven unipolar generator.

3. The method according to claim 2 , wherein the motor-driven unipolar generator has a voltage of approximately 0.8 kV and a current of approximately 6 kA to excite the generator.

4. A generator system comprising:

a first exciter device for exciting a field winding of a rotor of a generator;

a motor-driven second exciter device for continuous operation while operating the generator; and

at least a switch for switching from the first exciter device to the second exciter device to the field winding of the generator in case of a malfunction of the generator.

5. The generator system according to claim 4 , further comprising an excitation transformer operating the at least one switch, and an excitation unit, wherein via the excitation unit, the first exciter device or the second exciter device excite the generator.

6. The generator system according to claim 5 , wherein the excitation unit comprises a main excitation unit and a ceiling excitation unit, the excitation transformer switching from the main excitation unit to the ceiling excitation unit during a malfunction of the first exciter device, wherein via the ceiling excitation unit, the second exciter device excites the generator.

7. The generator system according to claim 5 , wherein the excitation unit comprises a main excitation unit and a ceiling excitation unit, with the excitation unit, the main excitation unit and the ceiling excitation unit each comprising at least one thyristor bridge with each thyristor of the at least one thyristor bridge of each the excitation unit, the main excitation unit and the ceiling excitation unit, connected in a parallel configuration.

8. The generator system according to claim 5 , wherein the second exciter device comprises a motor-driven unipolar generator with a voltage of approximately 0.8 kV and a current of approximately 6 kA to excite the generator.

9. The generator system according to claim 4 , wherein the second exciter device comprises a motor-driven flywheel for storing mechanical energy and for releasing the stored mechanical energy as electrical energy in case of a malfunction of the generator.

10. The generator system according to claim 4 , wherein the second exciter device comprises a pump for storing mechanical energy and for releasing the mechanical energy converted into electrical energy in case of a malfunction of the generator.

11. A method of using the generator system according to claim 4 , comprising:

exciting the field winding of the rotor of the generator using the first exciter device;

operating the motor-driven second exciter device continuously while operating the generator; and

switching via the switch from the first exciter device to the second exciter device to the field winding of the generator in a case of a malfunction of the generator.