INSTALLATION AND METHOD FOR GENERATING A THREE-PHASE AC VOLTAGE TO BE FED INTO A POWER SUPPLY SYSTEM

Abstract

An installation for generating a three-phase AC voltage to be fed into a power supply system, having a transformer connected to a three-phase generator on the output side to convert a first three-phase AC voltage into a second three-phase AC voltage having a second voltage level, which is lower than a first voltage level and a first frequency, and having a frequency converter connected to the transformer on the output side to supply a rotor winding with a third three-phase AC voltage to convert the second three-phase AC voltage into the third three-phase AC voltage having the second voltage level and a second frequency which is lower than the first frequency, wherein the frequency converter is designed such that the second frequency corresponds to a difference between a mains frequency of the power supply system and the first frequency.

Claims

1. An installation for generating a three-phase AC voltage to be fed into a power supply system, comprising: at least one turbine and at least one three-phase generator driven by the turbine, wherein a generator rotor of the three-phase generator is coupled to a turbine rotor of the turbine for conjoint rotation, at least one transformer which is electrically connected to the three-phase generator on the output side and by which a first three-phase AC voltage generated by the three-phase generator and having a first voltage level and a first frequency is able to be converted into a second three-phase AC voltage having a second voltage level, which is lower than the first voltage level, and the first frequency, at least one frequency converter which is electrically connected to the transformer on the output side and via which a rotor winding of the generator rotor is able to be supplied with a third three-phase AC voltage and by which the second three-phase AC voltage having the second voltage level and the first frequency is able to be converted into the third three-phase AC voltage having the second voltage level and a second frequency, which is lower than the first frequency, wherein the frequency converter is designed or controllable and/or regulatable in such a way that the second frequency corresponds to a difference between a power supply system frequency of the power supply system and the first frequency.

2. The installation as claimed in claim 1, further comprising: at least one three-phase capacitor bank connected in parallel with an output circuit of the frequency converter.

3. The installation as claimed in claim 1, further comprising: at least one electronic control and/or regulation unit which is connected to the frequency converter in terms of communication technology and which is configured to detect an instantaneous difference between the power supply system frequency of the power supply system and the first frequency and to drive the frequency converter depending on the instantaneous difference.

4. A method for generating a three-phase AC voltage to be fed into a power supply system using at least one turbine and at least one three-phase generator driven by the turbine, wherein a generator rotor of the three-phase generator is coupled to a turbine rotor of the turbine for conjoint rotation, the method comprising: generating a first three-phase AC voltage by the three-phase generator which has a first voltage level and a first frequency which is converted into a second three-phase AC voltage having a second voltage level, which is lower than the first voltage level, and the first frequency by a transformer which is electrically connected to the three-phase generator on the output side, supplying a rotor winding of the generator rotor with a third three-phase AC voltage by a frequency converter which is electrically connected to the transformer on the output side, converting the second three-phase AC voltage having the second voltage level and the first frequency into the third three-phase AC voltage having the second voltage level and a second frequency, which is lower than the first frequency, by the frequency converter, and generating the third three-phase AC voltage by the frequency converter in such a way that the second frequency corresponds to a difference between a power supply system frequency of the power supply system and a rotational frequency of the generator rotor.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

[0027] The invention is explained by way of example below on the basis of an embodiment with reference to the accompanying figure, wherein the features presented below, either in each case by themselves or in various combinations with one another, can constitute a developing or advantageous aspect of the invention. In the figure:

[0028] FIG. 1 shows a schematic illustration of one exemplary embodiment of an installation according to the invention.

DETAILED DESCRIPTION OF INVENTION

[0029] FIG. 1 shows a schematic illustration of one exemplary embodiment of an installation 1 according to the invention for generating a three-phase AC voltage to be fed into a power supply system 2.

[0030] The installation 1 comprises a turbine 3 in the form of a 50 Hz gas turbine, and a three-phase generator 4 driven by the turbine 3. The three-phase generator 4 comprises a three-phase stator 5 in the form of a 60 Hz three-phase stator and a generator rotor 6. The generator rotor 6 of the three-phase generator 4 is coupled to a turbine rotor (not shown) of the turbine 3 for conjoint rotation. The three-phase generator 4 is connected to the power supply system 2 via a disconnecting switch 7 and a machine transformer 8.

[0031] The installation 1 furthermore comprises a transformer 9 which is electrically connected to the three-phase generator 4 on the output side and by which a first three-phase AC voltage generated by the three-phase generator 4 and having a first voltage level and a first frequency is able to be converted into a second three-phase AC voltage having a second voltage level, which is lower than the first voltage level, and the first frequency.

[0032] Moreover, the installation 1 comprises a frequency converter 10 which is electrically connected to the transformer 9 on the output side and via which a rotor winding (not shown) of the generator rotor 6 is able to be supplied with a third three-phase AC voltage and by which the second three-phase AC voltage having the second voltage level and the first frequency is able to be converted into the third three-phase AC voltage having the second voltage level and a second frequency, which is lower than the first frequency. The frequency converter 10 is designed or controllable and/or regulatable in such a way that the second frequency corresponds to a difference between a power supply system frequency of the power supply system 2 and the first frequency.

[0033] The three phases of the rotor winding of the generator rotor 6 are electrically connected to sliprings (not shown) on a rotor shaft 13 of the generator rotor 6. A three-phase brush system (not shown) runs on the sliprings, said brush system being constructed from a plurality of carbon brushes (not shown) per phase and being mounted on a stationary brush apparatus 14. Via the brush system and via the stationary three-phase brush apparatus 14, the third three-phase voltage is transmitted from the frequency converter 10 to the rotor winding of the rotating generator rotor 6.

[0034] Furthermore, the installation 1 comprises a three-phase capacitor bank 11 connected in parallel with an output circuit (not shown) of the frequency converter 10.

[0035] Furthermore, the installation 1 comprises an electronic control and/or regulation unit 12 which is connected to the frequency converter 10 in terms of communication technology and which is configured to detect an instantaneous difference between the power supply system frequency of the power supply system 2 and the first frequency and to drive the frequency converter 10 depending on the instantaneous difference.

[0036] Although the invention has been more specifically illustrated and described in detail by means of the exemplary embodiment, nevertheless the invention is not restricted by the example disclosed and other variations can be derived therefrom by the person skilled in the art, without departing from the scope of protection of the invention.