Patent Application
20120225750
The subject matter disclosed herein relates to turbines and, more particularly, to an apparatus configured to enable steady low-speed turbine operation.
Some power plant systems, for example certain nuclear, simple-cycle and combined-cycle power plant systems, employ turbines in their design and operation. As each turbine does not become self-sustaining until it achieves a relatively high percentage of its designed full shaft speed, between about 90% and about 100% of design full shaft speed, each turbine is operably connected to a driveshaft whereby it may receive a power input assisting it in reaching a self-sustaining speed. One or more drive-trains may be coupled to the driveshaft, the drive-trains being used in part for transient operation, to manage and power the turbines and turbine rotors during mapping, start-up and cool-down periods. In operation, these drive-trains accelerate a turbine through low shaft speeds to a speed at which the turbine is self-sustaining.
In order to meet the high shaft power demands of the turbine, large torque converters and motors are designed into the drive-trains. However, these high power components may have mechanical limitations which result in a system which is unable to operate the turbine at a steady low-speed between about 2% and about 30% of full shaft design speed. The limited operational range which results from these mechanical limitations leads to increased compressor rubs, inefficient cranking and cool-down operations and gaps in aerodynamic mapping and testing plans which are used to create a profile of flow characteristics and element performance within the compressor and turbine. Therefore, it is desirable to increase the operational range of turbines, enabling operation across a range of design speeds, including steady operation at low design speeds between about 2% and about 30% of full shaft design speed. Some power plant systems use a sub-scale system to simulate and calculate mapping values for the turbine, creating a smaller version of the system which is then operable across a full range of speeds. These systems are expensive and take a long time to create and test. They provide mapping values which are converted estimates of values for steady low-speed operation on a full size turbine and they do not have an impact on the quality or duration of cool-down and start-up operations.
Systems for increasing the operational range of a turbine are disclosed. In one embodiment, an apparatus includes: a turbine coupled to a driveshaft; a drive-train coupled to the driveshaft; a first torque convertor coupled to the drive-train, the first torque convertor being configured to deliver an operational torque to the drive-train; a second torque convertor coupled to the first torque convertor, the second torque convertor being configured to deliver a torque to the first torque convertor; a first motor coupled to the second torque convertor, the first motor being configured to deliver a power input to the second torque convertor; and a control system operably connected to at least one of the first torque convertor and the second torque convertor, the control system configured to monitor and adjust a speed of the drive-train by controlling at least one of the operational torque provided by the first torque converter and the torque provided by the second torque converter.
A first aspect of the invention provides an apparatus including: a turbine coupled to a driveshaft; a drive-train coupled to the driveshaft; a first torque convertor coupled to the drive-train, the first torque convertor being configured to deliver an operational torque to the drive-train; a second torque convertor coupled to the first torque convertor, the second torque convertor being configured to deliver a torque to the first torque convertor; a first motor coupled to the second torque convertor, the first motor being configured to deliver a power input to the second torque convertor; and a control system operably connected to at least one of the first torque convertor and the second torque convertor, the control system configured to monitor and adjust a speed of the drive-train by controlling at least one of the operational torque provided by the first torque converter and the torque provided by the second torque converter.
A second aspect of the invention provides a system including: a dynamoelectric machine; a turbine operably connected to the dynamoelectric machine, the turbine including a driveshaft; and an apparatus operably connected to the turbine, the apparatus comprising: a drive-train coupled to the driveshaft of the turbine; a first torque convertor coupled to the drive-train, the first torque convertor being configured to deliver an operational torque to the drive-train; a second torque convertor coupled to the first torque convertor, the second torque convertor being configured to deliver a torque to the first torque convertor; a first motor coupled to the second torque convertor, the first motor being configured to deliver a power input to the second torque convertor; and a control system operably connected to at least one of the first torque convertor and the second torque convertor, the control system configured to monitor and adjust a speed of the drive-train by controlling at least one of the operational torque provided by the first torque converter and the torque provided by the second torque converter.
A third aspect of the invention provides an apparatus including: a drive-train; a first torque convertor coupled to the drive-train, the first torque convertor being configured to deliver an operational torque to the drive-train; a second torque convertor coupled to the first torque convertor, the second torque convertor being configured to deliver a torque to the first torque convertor; a first motor coupled to the second torque convertor, the first motor being configured to deliver a power input to the second torque convertor; and a control system operably connected to at least one of the first torque converter and the second torque converter, the control system adapted to control and adjust a speed of the drive-train by performing actions comprising: regulating an input of the first motor to the second torque convertor; monitoring a speed of the drive-train; and controlling an amount of torque conversion in at least one of the first torque convertor and the second torque convertor.
These and other features of this invention will be more readily understood from the following detailed description of the various aspects of the invention taken in conjunction with the accompanying drawings that depict various embodiments of the invention, in which:
It is noted that the drawings of the disclosure may not be to scale. The drawings are intended to depict only typical aspects of the disclosure, and therefore should not be considered as limiting the scope of the disclosure. In the drawings, like numbering represents like elements between the drawings.
As indicated above, aspects of the invention provide for systems configured to increase the operational range of a turbine, enabling the turbine to be operated at low-speeds for extended periods of time by employing a motor and torque converters connected in series to power and manage the turbine. The motor is operably connected to a first and a second torque converter which are operably connected to one another and communicatively connected to a control system. The first torque converter obtains a power input from the motor and, at the direction of the control system, the first and second torque converter convert the input into an operational torque which the second torque converter delivers to the turbine driveshaft via a drive-train. These systems may allow for maintaining and adjusting low-speed turbine operation, providing for more efficient start-up and cool-down operations and a more comprehensive mapping profile for the turbine and turbine elements.
In the art of power generation systems (including, e.g., nuclear reactors, steam turbines, gas turbines, etc.), turbines are often employed as part of the system and may include a drive-train for assisting the turbine in achieving a high shaft speed, e.g. where the turbine is self-sufficient. Typically, the drive-train may also assist the turbine with cool-down, cranking and mapping procedures. However, the torque, power, size and speed requirements which are designed into the drive-train to operate the turbine through transient states and at high-load applications may limit the operational versatility of the drive-train. The mechanical limitations of the large devices which are used to meet such demands prevent the drive-train from operating the turbine at a steady state across a full range of speeds. The drive-train is powerful enough to accelerate and decelerate the large turbine through low speeds, but not precise enough to enable steady low-speed turbine operation. This lack of range in turbine performance increases the amount of time required in cranking and cool down operations, and results in an incomplete mapping profile of the turbine.
Turning to the FIGURES, embodiments of an apparatus configured to enable steady low-speed turbine operation are shown, where the apparatus may increase mapping capabilities and decrease cool-down and start-up times of the turbine, the rotor and the overall power generation system by powering and managing turbine operation with a motor and multiple torque converters. Each of the components in the FIGURES may be connected via hardwired, wireless, or other conventional means as is indicated in
In an embodiment of the present invention, motor 110 of apparatus 100 may power turbine 140 via at least one shaft 115 coupled to each of turbine 140, torque converter 120 and torque converter 130. In another embodiment of the present invention, motor 110 of apparatus 100 may power turbine 140 via a common shaft 115 coupled to each of turbine 140, torque converter 120 and torque converter 130. In another embodiment of the invention, first torque converter 120 and second torque converter 130 may be connected in series via a common shaft 115.
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The apparatus and method of the present disclosure is not limited to any one particular drive-train, turbine, generator, power generation system or other system, and may be used with other power generation systems and/or systems (e.g., combined cycle, simple cycle, nuclear reactor, etc.). Additionally, the apparatus of the present invention may be used with other systems not described herein that may benefit from the increased operational range, stability and aerodynamic mapping capabilities of the apparatus described herein.
The terminology used herein is for the purpose of describing particular embodiments only and is not intended to be limiting of the disclosure. As used herein, the singular forms “a”, “an” and “the” are intended to include the plural forms as well, unless the context clearly indicates otherwise. It will be further understood that the terms “comprises” and/or “comprising,” when used in this specification, specify the presence of stated features, integers, steps, operations, elements, and/or components, but do not preclude the presence or addition of one or more other features, integers, steps, operations, elements, components, and/or groups thereof.
This written description uses examples to disclose the invention, including the best mode, and also to enable any person skilled in the art to practice the invention, including making and using any devices or systems and performing any incorporated methods. The patentable scope of the invention is defined by the claims, and may include other examples that occur to those skilled in the art. Such other examples are intended to be within the scope of the claims if they have structural elements that do not differ from the literal language of the claims, or if they include equivalent structural elements with insubstantial differences from the literal languages of the claims.
