IPC분류정보
국가/구분 |
United States(US) Patent
등록
|
국제특허분류(IPC7판) |
|
출원번호 |
US-0886868
(2010-09-21)
|
등록번호 |
US-8247919
(2012-08-21)
|
우선권정보 |
CH-0444/08 (2008-03-25) |
발명자
/ 주소 |
- Hoffmann, Jürgen
- Meindl, Thomas
|
출원인 / 주소 |
|
대리인 / 주소 |
|
인용정보 |
피인용 횟수 :
2 인용 특허 :
8 |
초록
▼
A combined-cycle power plant (10) has at least one power train (60) including a steam turbine (24) and a second generator (8) directly driven by the steam turbine (24) and generating alternating current, the output of which generator is connected to a power grid (21) having a given grid frequency (F
A combined-cycle power plant (10) has at least one power train (60) including a steam turbine (24) and a second generator (8) directly driven by the steam turbine (24) and generating alternating current, the output of which generator is connected to a power grid (21) having a given grid frequency (F), and at least one power train (11) of a gas turbine (12) and a first generator (18) driven directly by the gas turbine (12) and generating alternating current with an operating frequency, the output of which generator is connected to a power grid (21) having a predetermined grid frequency. An electronic decoupling device or a variable electronic gear unit (27) decouples the operating frequency from the grid frequency and is arranged between the first generator (18) and the power grid (21). Such a plant allows both flexible steady-state operation with high overall efficiency as well as flexible transient operation.
대표청구항
▼
1. A method of operating a power plant, the method comprising: providing at least one power train having at least one steam turbine and a second AC generator;providing at least one power train having at least one gas turbine and a first AC generator;providing a frequency converter between the first
1. A method of operating a power plant, the method comprising: providing at least one power train having at least one steam turbine and a second AC generator;providing at least one power train having at least one gas turbine and a first AC generator;providing a frequency converter between the first AC generator and a power grid having a given grid frequency, wherein the frequency converter comprises a variable electronic gear unit;connecting the outputs of the first AC generator and the second AC generator to the power grid;directly driving the first AC generator with the at least one gas turbine at an operating frequency;directly driving the second AC generator with the at least one steam turbine;forcing a speed with the variable electronic gear unit onto the at least one gas turbine with a transmission ratio between the mechanical speed of the at least one gas turbine and the grid frequency via the first AC generator; anddirectly frequency coupling the second AC generator to said power grid. 2. The method as claimed in claim 1, further comprising: providing a grid frequency pick-up, a speed measurement unit for the first generator, and a gas turbine controller; andcommunicating speed data from the measurement unit to the controller. 3. The method as claimed in claim 1, wherein forcing a speed comprises forcing with a transmission ratio which is not constant. 4. The method as claimed in claim 1, wherein forcing a speed comprises forcing with a transmission ratio which is constant. 5. The method as claimed in claim 1, wherein: the grid frequency is 60 Hz;directly driving the first AC generator comprises driving at an operating frequency of 50 Hz; anddirectly driving the second AC generator comprises driving at an operating frequency of 60 Hz. 6. The method as claimed in claim 1, wherein: the grid frequency is 50 Hz;directly driving the first AC generator comprises driving at an operating frequency of 60 Hz; anddirectly driving the second AC generator comprises driving at an operating frequency of 50 Hz. 7. The method as claimed in claim 1, wherein providing a frequency converter comprises providing a matrix converter. 8. The method as claimed in claim 7, wherein providing a matrix converter comprises providing a controller and a plurality of controllable bidirectional switches arranged in an (m×n) matrix, the switches being configured and arranged to selectively connect m inputs to n outputs, where m is greater than n; determining the signs of the currents in the inputs;determining the signs of the voltages between the inputs;communicating said voltage and current signs to the controller; andcontrolling the switches with the controller based on said voltage and current signs. 9. A power plant comprising: at least one power train having at least one steam turbine and a second AC generator directly driven by the at least one steam turbine, the output of the second AC generator to be connected to a power grid having a given grid frequency; andat least one power train having at least one gas turbine and a first AC generator with an operating frequency driven directly by the at least one gas turbine, the output of which first AC generator to be connected to said power grid;a frequency converter arranged between the first AC generator and the power grid;wherein the second AC generator is coupled directly with respect to frequency to said power grid;wherein the frequency converter comprises at least one matrix converter; andwherein said at least one matrix converter is configured and arranged to smooth current delivered to the power grid by superimposing current generated by the at least one first AC generator and delivered to the power grid on current generated by the second AC generator. 10. The power plant as claimed in claim 9, wherein the at least one gas turbine comprises a sequential combustion gas turbine. 11. The power plant as claimed in claim 9, wherein the at least one gas turbine has a design frequency of less than 50 Hz. 12. The power plant as claimed in claim 9, wherein the at least one gas turbine is configured and arranged for variations in the aerodynamic speed of less than plus/minus 10%. 13. The power plant as claimed in claim 9, wherein the at least one gas turbine comprises a compressor with a distance from the surge limit of less than 10% of the aerodynamic speed at design conditions. 14. The power plant as claimed in claim 9, further comprising: a water/steam cycle configured and arranged for full-load variations in an exhaust gas mass flow of the at least one gas turbine of less than plus/minus 5%. 15. A method for operating a power plant, the method comprising: providing a power plant comprising at least one power train having at least one steam turbine and a second AC generator directly driven by the at least one steam turbine, the output of the second AC generator to be connected to a power grid having a given grid frequency,at least one power train having at least one gas turbine and a first AC generator with an operating frequency driven directly by the at least one gas turbine, the output of which first AC generator to be connected to said power grid,a frequency converter arranged between the first AC generator and the power grid, andwherein the second AC generator is coupled directly with respect to frequency to said power grid;permanently coupling the speed of the at least one steam turbine to the grid frequency of the electrical power grid; andcontrolling the aerodynamic speed of the at least one gas turbine. 16. The method as claimed in claim 15, wherein: the first AC generator is separated from the grid frequency by an electronic decoupling device; andcontrolling comprises controlling the speed of the at least one gas turbine independent of the grid frequency. 17. The method as claimed in claim 15, wherein controlling comprises controlling the mechanical or aerodynamic speed of the at least one gas turbine as a function of at least one parameter of the power plant. 18. The method as claimed in claim 15, wherein controlling comprises controlling the mechanical or aerodynamic speed of the at least one gas turbine as a function of exhaust gas enthalpy, exhaust gas temperature, exhaust gas mass flow, or combinations thereof. 19. The method as claimed in claim 15, wherein the at least one gas turbine comprises a compressor configured and arranged to compress combustion air, and further comprising: measuring the discharge pressure of the compressor, the final temperature of the compressor, the feed-in conditions of cooling air branched off from the compressor, or combinations thereof; andcontrolling the mechanical or aerodynamic speed of the at least one gas turbine based on said measuring. 20. The method as claimed in claim 15, further comprising: predetermining a target power for the operation of the at least one gas turbine; andcontrolling the mechanical or aerodynamic speed of the at least one gas turbine as a function of the target power. 21. The method as claimed in claim 15, wherein controlling comprises controlling the mechanical speed to a constant value as soon as at least one limit value is reached. 22. The method as claimed in claim 15, wherein controlling comprises controlling to control targets optimized in dependence on the conditions of erection of the power plant. 23. The method as claimed in claim 15, wherein controlling comprises controlling the ratio of the mechanical or aerodynamic speed of the at least one gas turbine to the grid frequency to a constant value. 24. The method as claimed in claim 15, further comprising: transmitting a nominal speed formed by a controller of the water/steam cycle to a controller of the at least one gas turbine, to a controller of the variable electronic gear unit, or to both. 25. The method as claimed in claim 15, wherein controlling comprises controlling the mechanical or aerodynamic speed of the at least one gas turbine via a transmission ratio between the mechanical speed and the grid frequency. 26. The method as claimed in claim 25, further comprising: transmitting a nominal speed formed by a controller of the gas turbine to a controller of a variable electronic gear unit. 27. The method as claimed in claim 15, wherein the at least one steam turbine changes speed with the grid frequency, and wherein, with longer-lasting changes in the grid frequency, controlling comprises maintaining the mechanical or aerodynamic speed of the gas turbine constant and adapting the power of the at least one gas turbine without delay. 28. The method as claimed in claim 27, further comprising: preceding an anticipated under-frequency event, increasing the speed of the at least one gas turbine. 29. The method as claimed in claim 28, further comprising: maintaining the power output of the power plant constant during said increasing speed. 30. The method as claimed in claim 27, further comprising: preceding an anticipated over-frequency event, decreasing the speed of the at least one gas turbine. 31. The method as claimed in claim 30, further comprising: maintaining the power output of the power plant constant during said decreasing speed. 32. The method as claimed in claim 15, wherein, when short-term over-frequency or under-frequency events occur in the power grid, the at least one steam turbine speed changes with the grid frequency, and wherein controlling comprises changing the mechanical speed of the at least one gas turbine in a controlled manner. 33. The method as claimed in claim 32, wherein controlling comprises, upon an under-frequency of the power grid, decreasing the mechanical speed of the at least one gas turbine to a greater or lesser extent than the grid frequency. 34. The method as claimed in claim 32, wherein controlling comprises, upon an over-frequency of the power grid, increasing the mechanical speed of the at least one gas turbine to a greater or lesser extent than the grid frequency. 35. The method as claimed in claim 32, wherein controlling comprises controlling the speed gradient of the at least one gas turbine to take a predetermined kinetic power from a shaft assembly of the at least one gas turbine and feed it as electrical power into the power grid.
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