Load prediction system for power generation systems

Abstract

A system and method includes an AC motor and one or more gas turbine generators configured to supply power to the AC motor. The system further includes a controller configured to control operation of the one or more gas turbine generators by determining that the AC motor will be started using electric power. When determining that the AC motor will be started using electric power, the controller is configured to boost the electric power prior to starting the AC motor. The controller uses the boosted electric power to pre-compensate for a decrease in an electrical parameter of the electric power due to an increased demand for starting the AC motor.

Description

Technical Field

[0001] The subject matter disclosed herein relates to the use of a gas turbine engine in the supply of power to a load. Specifically, the gas turbine engine is used to generate energy that can be converted into electrical energy.

Background Art

[0002] Generally, a gas turbine engine burns a mixture of compressed air and fuel to generate combustion gases. The combustion gases can flow through one or more turbine stages to produce power for a load and / or a compressor. A gas turbine can be used to power a generator that supplies electrical energy to a load and / or a motor. However, some states of some loads (e.g., bump start) can impose a large (e.g., 30 - 80 MW) and almost instantaneous demand (e.g., 0.5 - 1.5 seconds) on a gas turbine power generation system, and there is a possibility that the gas turbine power generation system cannot supply power sufficiently at rated operating parameters due to a decrease in frequency and / or voltage, i.e., the possibility of a brownout.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

[0004] Several embodiments of the invention that are equivalent in scope to the invention as described in the original claims are summarized below. These embodiments are not intended to limit the scope of the invention as described in the claims, but rather are intended to provide a brief overview of possible forms of the invention. In fact, the invention can encompass a variety of forms that may be similar to or different from the embodiments described below. In the first embodiment, the system includes an AC motor and one or more gas turbine generators configured to supply power to the AC motor. The system further includes a controller configured to control the operation of one or more gas turbine generators by determining whether the AC motor is to be started using power. When it is determined that the AC motor is to be started using power, the controller is configured to boost the power prior to starting the AC motor. The controller uses the boosted power to preemptively compensate for any decrease in the electrical parameters of the power resulting from the increased demand for starting the AC motor.

[0005] In a second embodiment, the system includes a high-power load and a turbine generator configured to supply power to the high-power load. The system further includes a controller that, with respect to the high-power load, when it determines that a sharp increase in demand is scheduled, augments one or more modes of power to preemptively compensate for a reduction in one or more modes of power resulting from a sharp increase in scheduled power demand. Furthermore, the controller can determine a decrease in power demand for the high-power load and achieve a reduction in one or more modes of power.

[0006] In a third embodiment, a tangible, non-temporary computer-readable medium stores instructions that cause the processor to manage the operation of a gas turbine system for generating power when executed by the processor. Furthermore, the processor can execute the instructions to determine that the motor should be started according to a scheduled start. Furthermore, prior to starting the motor, the processor increases at least one parameter of the power to be generated in order to compensate in advance for a decrease in at least one parameter of the power to be generated, and starts the motor using the increased at least one parameter of the power to be generated.

[0007] These features, aspects, and advantages of the present invention, as well as other features, aspects, and advantages, will be better understood by considering the following detailed description with reference to the accompanying drawings. In the accompanying drawings, similar reference numerals represent similar parts throughout the drawings. [Brief explanation of the drawing]

[0008] [Figure 1] This is a block diagram of a gas turbine engine configured to supply power to a load according to one embodiment of the present disclosure. [Figure 2] This is a block diagram of a gas turbine engine configured to power one or more motors and a generator that supplies power to a load, according to one embodiment of the present disclosure. [Figure 3] This is a perspective view of two gas turbine engines configured to power one or more loads according to one embodiment of the present disclosure. [Figure 4] This is a graph of generator frequency versus generator output according to one embodiment of the present disclosure. [Figure 5] This is a flowchart for predicting an increase in power demand and compensating for that increase in power demand in advance during the operation of a gas turbine generator, according to one embodiment of the present disclosure. [Figure 6]This is a graph of various electrical parameters of circuit elements before, during, and after a gas turbine generator supplies power to a load using pre-compensation for the power load demand of the gas turbine generator according to one embodiment of the present disclosure. [Modes for carrying out the invention]

[0009] One or more specific embodiments of this disclosure are described below. In an effort to provide a concise description of these embodiments, not all features of the actual embodiments may be described herein. It should be understood that in developing any such actual embodiment, as in any engineering or design project, numerous embodiment-specific decisions must be made to achieve the developer's specific goals, which may differ from embodiment to embodiment, such as compliance with system-related and business-related constraints. It should also be understood that while such development efforts may be complex and time-consuming, they are still routine in design, fabrication, and manufacturing for those skilled in the art who benefit from this disclosure.

[0010] When describing elements of various embodiments of the present invention, the articles “a,” “an,” “the,” and “said” are intended to indicate that there is one or more of those elements. The terms “comprising,” “including,” and “having” are intended to be inclusive and to indicate that there may be further elements other than those listed. Furthermore, the term “or” is intended to be inclusive and A or B indicates that A only, B only, or both A and B.

[0011] This disclosure broadly relates to starting an AC motor using a generator operated by a gas turbine generator. When starting a high-power (e.g., 30 kilohorsepower (kHp)) AC motor (or other high-demand instantaneous loads), the gas turbine generator may experience demand spikes to such an extent that its output parameters (e.g., frequency or voltage) may decrease. In these high-demand loads, the demand rising over time may be difficult or impractical to achieve due to the increased cost or complexity of the system involving the high-demand load. Instead of letting the demand rise, the system can compensate for this drop in advance. During this advance compensation, the generator can be given a power boost before starting the high-power AC motor. This power boost also increases one or more of the parameters of the generator's operation that would otherwise suffer a decrease in output parameters. By giving the generator a power boost before starting the AC motor, the generator can prepare for the increase in power demand and respond to the increase in power demand in a stable manner, allowing the generator to quickly recover steady-state balanced operation (e.g., rated operating frequency and voltage) while starting the AC motor or other attached loads.

[0012] According to this embodiment, these processes and other processes can be performed or accelerated by a generator operated by a gas turbine system. Figure 1 is a block diagram of one embodiment of the gas turbine system 10. For example, the gas turbine system 10 may be part of a combined cycle system or may be combined with other gas turbine systems 10 to power one or more loads 12. Specifically, the gas turbine system 10 is generally configured to drive the loads 12 by burning a mixture of compressed air and fuel 15 (e.g., natural gas, light or heavy distilled oil, naphtha, crude oil, residue, or synthesis gas). Combustion is performed in a combustor 16 which may include one or more combustion chambers. Air 14 enters the intake of a compressor 20, is filtered, and then compressed in the compressor 20 by one or more compression stages.

[0013] To initiate the combustion process in the combustor 16, air 14 is injected into the combustor 16 by a compressed air stream 18. The compressed air stream 18 is mixed with fuel 15. The mixture of fuel 15 and air 14 can be used to produce ignition. Ignition generates high-temperature combustion gases 26 that power the gas turbine system 10. More specifically, the high-temperature combustion gases 26 flow through a turbine 28 having one or more compression stages that drive a load 12 via a shaft 30. For example, the combustion gases 26 can impart power to the turbine rotor blades in the turbine 28 (e.g., via convection, expansion, etc.) and rotate the shaft 30. In an exemplary process, the high-temperature combustion gases 26 can cause the turbine blades in the turbine 28 to rotate the shaft 30 along the axis of the gas turbine system 10. As shown in the figure, the drive shaft 30 can be connected to various components of the gas turbine system 10, including a compressor 20 or a load 12.

[0014] As already mentioned, the drive shaft 30 can connect the turbine 28 to the compressor 20 to form a rotor. The compressor 20 may include compressor blades coupled to the drive shaft 30. Thus, the rotation of the turbine blades in the turbine 28 causes the drive shaft 30 connecting the turbine 28 to the compressor 20 to rotate the compressor blades in the compressor 20. This rotation of the compressor blades in the compressor 20 causes the compressor 20 to compress the air 14 to produce a compressed air stream 18. The compressed air stream 18 is then supplied to the combustor 16 and mixed with other combustion components, as previously described. The shaft 30 can drive the compressor 20 in addition to, or instead of, a load 12. For example, the load 12 may be, among other things, a generator, a propeller, a transmission, or a drive system.

[0015] Once the turbine 28 extracts work from the high-temperature combustion gas 26, it can bring a stream of exhaust gas 32 to the exhaust section 34, where the exhaust gas 32 can be cooled or further processed. For example, the exhaust section 34 can be a carbon monoxide (CO) catalyst, NO x The catalyst section 36 may include a catalyst, an unburned hydrocarbon catalyst, or any similar metal-based catalyst (e.g., a platinum-based catalyst). For example, in the illustrated embodiment, the catalyst section 36 includes NO in the stream of exhaust gas 32. x NO configured to destroy gas x This may include a catalyst or a CO catalyst. The stream of exhaust gas 32 can then exit the exhaust section 34.

[0016] As shown in the figure, the gas turbine system 10 includes a controller 38. The controller 38 may include one or more processors 66 and memory 68 which may be used collectively to support an operating system, software application, and system, etc., useful in the implementation of the technology described herein. In particular, the controller 38 may include code or instructions stored in a non-temporary machine-readable medium (e.g., memory 68) and executed by one or more processors 66 which may be included in the controller 38, for example. The processor 66 can receive operating parameters from various components of the gas turbine system 10, including the rotational speed of the shaft, the frequency of the power generated by the gas turbine system in the generator driven by the shaft 30, the voltage of the power, the demand from one or more loads 12, or other appropriate parameters. In some embodiments, some parameters are measured directly, while others are determined indirectly from other measurements. For example, in certain embodiments, the controller 38 may utilize an algorithmic model or a lookup table (e.g., stored in memory) to derive various parameters, such as the operating speed of the shaft 30 or the connected generator, using electrical parameters such as the frequency or voltage of the power generated by the generator. Furthermore, the controller 38 can monitor the operation of various parts of the gas turbine system 10. The monitored parameters can be used to control (e.g., adjust) the operating parameters of one or more aspects of the gas turbine system 10.

[0017] As shown in the figure, the controller 38 may include a forecasting circuit 39 that predicts a significant increase in demand. The forecasting circuit 39 causes the controller 38 to preemptively increase the output of the gas turbine system 10 and the connected generator. As previously mentioned, this preemptive increase compensates in advance for the decrease in electrical parameters that the generator would suffer in response to a large demand. The forecasting circuit 39 may include a physical circuit or may be at least partially embodied using instructions stored in memory 68 and executed on the processor 66 of the controller 38.

[0018] Figure 2 is a schematic diagram 40 of a gas turbine 28 that drives a generator 42 that supplies power to a load 12 or a motor 44. The motor 44 may include an electric motor that operates on the current generated by the generator 42. Each gas turbine 28 and generator 42 can work together to form a gas turbine generator 48. A shaft 30 that rotates by the torque generated using the gas turbine 28 can be connected to each generator 42. The rotation of the gas turbine 28 can power each generator 42. More specifically, the gas turbine 28 is connected to a rod in the generator 42 (e.g., coupled to the shaft 30) that can be used to generate electricity by a magnetic induction mechanism in the generator 42. The generator generates electrical energy by converting the rotational energy received from the shaft 30 into electrical energy. In other words, the generator converts rotational energy into electrical energy using magnetic induction. Due to the principle of magnetic induction, electric charge can be induced by moving a conductor through a magnetic field. The generator 42 utilizes this principle by rotating the shaft 30 through a magnetic field, or by moving one or more magnets within the magnetic field in the generator 42. This movement can induce electricity that can be used to operate a load 12 or motor 44 attached to the generator 42. Furthermore, the generator 42 may be electrically connected to one or more motors 44 or loads 12. Through this electrical connection, the generator 42 can provide electrical energy to operate the motors 44. As can be understood, the AC electricity generated by the generator 42 may have a frequency determined by the rotation of the magnets, which may be rotated by the rod of the generator 42. This rotation provides a torque that rotates the magnets, which are displaced within the magnetic field at a speed that gives rise to the frequency of the AC electricity. As will be described below, when load demand increases rapidly (e.g., almost instantaneously), one or more parameters of the electrical output of the generator 42 (e.g., frequency and / or voltage) may decrease due to attempts to meet a large and almost instantaneous demand.The prediction circuit 39 at least partially compensates in advance for the deterioration / decrease of the electrical parameters in response to this large demand. Further, the prediction circuit 39 can be made active and operative at any time to prepare for a large current inrush to the motor 44 (e.g., an AC motor).

[0019] As described above, the technology of this specification may be applied to a system including two or more turbines. FIG. 3 is a perspective view of a gas turbine system 50 having two gas turbines operating in parallel with each other. During operation of the gas turbine system 50, a plurality of generators (those that convert energy from the gas turbine engines 52, 54) can be connected to the bus to supply power to the motor 44 or the load 12. Some loads may require excessive power from one generator and / or one gas turbine. The plurality of generators connected and operating in parallel on the bus can help meet a large power demand and can assist in the operation of the generators to withstand a sudden increase in power demand such as can occur when starting a high-power AC motor.

[0020] In the operation of the gas turbine system 50, the air inlets 76 and 78 take in air (e.g., ambient air). The first air compressor 80 (e.g., one or more compression stages) of the first gas turbine engine 52 and the second air compressor 82 (e.g., one or more compression stages) of the second gas turbine engine 54 compress the taken-in air to generate compressed air.

[0021] The combustion of fuel (such as fuel 15) in the first and second gas turbine engines 52 and 54 is carried out in the respective first and second combustors 88 and 90. Further, each of the combustors 88, 90 can include a plurality of combustion chambers. When combustion gases are generated in the first and second combustors 88 and 90, they are sent to the first gas turbine 92 of the first gas turbine engine 52 and the second gas turbine 94 of the second gas turbine engine 54 respectively, where work is extracted from the high-temperature combustion gases as described above with respect to FIG. 1. The work extracted by the first and second gas turbines 92 and 94 can cause rotation of one or more features such as a shaft connecting the gas turbines 92, 94 to their respective loads 96 and 98. Instead of this, or in addition, the gas turbines 92 and 94 can drive the respective compressors 80, 82 of the first and second gas turbine engines 52 and 54, and any other loads such as generators, propellers, etc. by extracting work from the combustion gases generated in the combustors 88 and 90.

[0022] The system 50 has been described as having two gas turbine engines (the first gas turbine engine 52, the second gas turbine engine 54), but it should be noted that the present method is also applicable to systems that use any number of gas turbine engines to operate one or more generators.

[0023] As mentioned above, each pair of gas turbines 28 and generators 42 may be located in a single unit (e.g., gas turbine generator 48) or may be separate machines connected to each other. Furthermore, the gas turbine generator 48 may include one or more controller mechanisms (e.g., controller 38) for adjusting various parameters of the generator 42 (e.g., voltage, frequency, etc.), the gas turbine 28, or both the generator 42 and the gas turbine 28. As mentioned above, the generator 42 can be electrically connected to the motor 44 to supply energy for operation. Furthermore, in order to obtain efficient power transfer to the motor 44 to be started, the generator 42 may be configured to match the reactance and impedance of the motor 44 and / or other motors and loads in the system 10. By configuring the circuit elements of the generator 42 so that the reactance and impedance values ​​match, efficient power transfer between the generator 42 and the motor 44 can be enabled.

[0024] As mentioned above, the gas turbine system 10 may include two or more gas turbines, each having two or more shafts. A multi-shaft configuration can enable a wider range of load-accepting shot capabilities due to a constant combustion flow at a given free turbine speed. However, multi-shaft freewheeling power turbines may still have limited load-accepting shot capabilities, particularly when operating with light power demands. When a gas turbine is operating under a light load and then suddenly faces an increase in power demand (e.g., starting the motor 44), the amount of power demand that the generator 42 can meet before facing current saturation or excessive torque in the process of trying to meet this new power demand and stabilize itself is limited. Saturation can occur when the coils in the generator 42 become saturated with current, resulting in no increase in the magnitude of the magnetic field even if more current is applied, and instead energy dissipation (e.g., heat) occurs. Excessive torque can be applied to the rotor of the generator when the gas turbine tries to meet the increased power demand by supplying more power by applying excessive torque to the generator 42. Excessive torque can lead to damage to the generator 42 or its eventual shutdown. For example, the frequency of the generator 42 may drop below a certain threshold frequency, as described below. Above the threshold frequency, the gas turbine generator 48 may be unable to stably operate the electrically connected motor 44, creating a risk of saturation and / or excessive torque.

[0025] To prepare for high power demands, the gas turbine generator 48 can increase the operating parameters or output characteristics of one or both of the gas turbine 28 and the generator 42. For example, the generator frequency and output voltage of the generator 42 can be increased before supplying power to the motor 44 that receives power from the gas turbine generator 48. In this way, the generator 42 can prepare for load demands, increase load shot capability, and increase transition speed.

[0026] Figure 4 shows an exemplary graph 120 plotting generator frequency versus generator output. The generator frequency is measured in Hertz (Hz), and the power output of the generator output is measured in megawatts (MW). Graph 120 shows the load acceptance response of a generator rated to a frequency of 60 Hz and a voltage of 13.8 kV, and which can be configured for multiple voltage and frequency selections. As previously stated in this description, when a generator is subjected to an increase in load, the load can destabilize several parameters of the generator (e.g., frequency, current, voltage, output, etc.) due to the increase in power demand faced by the generator, especially when starting from a low-load state. As shown in graph 120, when the load on generator 42 increases, the output of generator 42 increases as it attempts to meet the increased power demand. As shown by the negative slope of line 122 in graph 120, the frequency of generator 42 decreases as the output of generator 42 increases to meet the new power demand. The frequency of generator 42 may initially decrease due to energy surges carried by generator 42. The frequency of generator 42 can correspond to the electrical frequency of the alternating current in the generator. Furthermore, a minimum threshold frequency 124 may exist, and below this minimum threshold frequency 124, generator 42 may become irrecoverable. Below the minimum threshold frequency 124, generator 42 may saturate or face excessive torque from the gas turbine. For example, in Figure 4, the minimum threshold frequency 124 corresponds to 57 Hz. However, the minimum threshold frequency shown in Figure 4 is for illustrative purposes only and is by no means limited to a specific value such as 57 Hz. Other minimum threshold frequencies exist based on factors such as the generator's frequency rating and temperature.

[0027] In some embodiments, the starting of an AC motor (e.g., motor 44) may be initiated without the AC motor having initial angular momentum. Such a start (e.g., starting a motor without initial angular momentum) may utilize a large power surge to start motor 44 and then stabilize the generator 42 at the new demand level. To accommodate this larger surge, the generator 42 may use its enhanced loadshot acceptance capacity to start motor 44 with a large power surge.

[0028] The enhanced load-shot acceptance capacity can be provided by pre-compensating for changes in the power parameters supplied by the generator 42. Line 126 traces the frequency of the generator 42's output using pre-compensation by increasing the frequency or voltage of the generator 42. For example, if the generator 42 outputs power at a voltage level of 13.8 kV and a frequency level of 60 Hz, as shown in the figure, the generator 42 can operate at a voltage level of 14.1 kV and a frequency level of 62 Hz during the period before the motor 44 is started. By increasing the frequency and voltage of this generator to operate at more than 1 PU (per unit) (e.g., about 1.03 times PU (per unit)) over a certain threshold period (e.g., 10, 15, 20 seconds) before the motor 44 is started, the output of the generator 42 can be increased to enable a greater load-sucking capacity. In fact, the output of the generator 42 may even reach a level twice the initial output and may still be able to stabilize after satisfying the load demand surge. This increase in output in one or more aspects (e.g., frequency or voltage) may improve the load acceptance of the generator 42 and accelerate the recovery speed of the generator 42. Thus, as described above, in the starting of a motor 44 that has no initial angular momentum, or in other situations where the load may require a large power surge, the prediction circuit 39 can prepare the generator 42, gas turbine 28, or gas turbine generator 48 by increasing one or more of the operating parameters (e.g., frequency, voltage, etc.) before starting the motor 44. Increasing the value of the operating parameter of the generator 42 can provide additional energy to meet the load demands in the process of starting or transition events.

[0029] Figure 5 is a flowchart of the process 150 for starting a motor 44 using a prediction circuit 39 connected to a gas turbine system 10. In block 152, the controller 38 operates the gas turbine system 10 to generate power. In block 154, the prediction circuit 39 determines whether the motor 44 can be started. For example, the prediction circuit 39 or the controller 38 can gain access to the operating schedule of the motor 44. If the motor 44 cannot be started, power generation can continue at the current demand. In block 156, if the motor 44 is about to be started, at least one parameter of the power to be generated is increased. Parameters that can be increased include the frequency, voltage, or other parameters of the power to be generated. These parameters can be increased simultaneously or sequentially before the generator 42 faces an increase in demand. Furthermore, in some embodiments, only one parameter of the power to be generated is increased, while in other embodiments, two or more parameters are increased.

[0030] In block 158, the motor 44 is given power for starting after increasing at least one parameter of the power to be generated. The increased at least one parameter may be capable of providing the additional energy that the generator 42 needs to maintain the increased load demand to the generator 42 during the transition event. Furthermore, as previously mentioned, two or more generators 42 may be connected to a bus that transfers electricity to the motor 44 to be started.

[0031] In block 160, after the generator 42 has successfully met the power demand to start the motor 44, the controller 38 can determine whether a backup generator was used to start the motor 44. The backup generator may provide more power than is used to operate the motor 44 and load 12. For example, if a backup generator is used, it may be shut off before starting the motor 44 and may not provide any additional power.

[0032] In block 162, if no spare generators are present on the bus, at least one parameter of the generated power increased in block 156 can be deducted from generator 42. In block 164, if a spare generator was used in the motor 44 starting process, the spare generator can be taken offline (for example, turned off or disconnected from the bus and wires that carry electricity to the motor). More than one spare generator may be used in the motor 44 starting process.

[0033] As mentioned above, when the generator 42 begins supplying power to the motor 44, the generator 42 may be disturbed from its steady state or equilibrium state because it is attempting to meet the increased demand. Figure 6 shows a graph 190 with multiple lines representing the parameters of the gas turbine system 10, generator 42, and motor 44 before, during, or after the transition event of increased power demand to the generator.

[0034] Line 200 corresponds to the output of generator 42. Line 204 corresponds to the power demand to generator 42 from various circuit elements electrically connected to generator 42 (e.g., load 12 and motor 44). Graph 190 shows several periods, namely the pre-start period 194, the pre-emphasis period 198, the start period 202, and the post-start period 206. In the pre-start period 194, generator 42 is operating in a steady state. In the pre-start period 194, generator 42 can operate according to the rated frequency (e.g., 50 or 60 Hz) and the respective rated voltage (e.g., 11.5 kV or 13.8 kV) at the moment before the motor starts. Furthermore, generator 42 may already be connected to load 12 or motor 44 and can maintain power demand by remaining in a relatively steady state.

[0035] According to this embodiment, during the pre-emphasis period 198, the generator 42 can be controlled to increase one or more of its operating parameters in preparation for starting the motor 44. The duration of the pre-emphasis period 198 corresponds to the period before motor starting, used to increase one or more of the parameters of the generated power to a higher level in order to compensate in advance for a decrease in one or more of the parameters of the generated power from the generator 42. This pre-emphasis period 198 can have a sufficient duration to allow the generator 42 to reach the output pre-emphasis level. The output at the pre-emphasis level corresponds to the increased operating values ​​of one or more of the parameters of the generated power (e.g., lines 192 and 196 in the pre-emphasis period 198). During the pre-emphasis period 198, the generator 42 begins to increase its frequency (as shown in line 192) and voltage (as shown in line 196) so that the generator can operate at a level above the rated frequency in the time before it faces new power demand.

[0036] Furthermore, the power demand and output of the generator (lines 204 and 200) can be increased during the start-up period 202 as part of starting the motor 44. During the start-up period 202, to preemptively compensate for a decrease in one or more operating parameters in an attempt to meet the increased demand, the controller 38 can instruct the generator 42 to increase one or more of the operating parameters (e.g., frequency and voltage) before the start-up period 202. During the start-up period 202, the frequency of the generator 42, indicated by line 192, drops sharply in the transition event. The frequency may drop sharply, at least in part, due to the demand to supply a large transfer angular momentum to the motor 44, which is started without initial angular momentum. A large energy transfer may be used to start the motor 44, which has no initial angular momentum. Through a series of energy conversions, the motor 44 can obtain the energy to start. That is, the generator 42 supplies electrical energy to the motor 44. The electrical energy that the motor 44 receives from the generator 42 to be started can be converted into rotational kinetic energy that provides torque to the motor 44 to change (e.g., increase) the angular momentum of the motor 44. The voltage indicated by line 196 of the generator 42 also faces a sharp drop due to the demand indicated by line 204 and the resulting output indicated by line 200. The generator 42 can be characterized as being out of equilibrium, unstable, or out of steady state during the starting period 202. In the post-start period 206, the increased demand for power for starting decreases from the peak level used to compensate for the initial lack of angular momentum in the motor 44 when starting the motor 44. The increased demand (for starting) decreases in the post-start period 206, at least in part, due to the fact that it becomes easier to maintain the angular momentum of the motor 44 (e.g., less torque is needed) after the motor 44 has been started without angular momentum. Therefore, in order to increase the angular momentum of the motor 44 from an initial state of no angular momentum, the amount of torque applied to the motor 44 from the energy derived from the generator 42 may need to be greater than the amount of torque applied to the motor 44 in order to maintain the angular momentum of the motor 44 at a relatively constant finite value.

[0037] Using pre-emptive compensation, the generator 42 is better equipped to recover from event transitions during the start-up period 202 to meet the increased power demand. This is true because one or more parameters of the generated power are increased in preparation for the increase in power demand, so that the generator 42 remains within its operating limits. For example, pre-emptive compensation ensures that the generator frequency does not fall below a minimum threshold frequency 124 during the start-up of the motor 44, preventing saturation of the generator 42.

[0038] Typically, a motor may require a large initial energy output because starting it may require more power than maintaining its operation. As shown in Figure 6, the output increases significantly during the time between the pre-emphasis period 198 and the start-up period 202. However, after the motor has gained rotational kinetic energy and angular momentum, the output of the generator 42 may decrease, as shown in the post-start-up period 206, to track the decrease in power demand. As a result of the decrease in output, other parameters of the generator, such as frequency and voltage, may also decrease.

[0039] Although the above describes a gas turbine driving a generator, similar principles can be applied to any power generation system that uses a prime mover to drive the generator. Specifically, the technology disclosed herein may be useful for any power generation system that may suffer from large and nearly instantaneous demands that could degrade at least one parameter of the power output from the power generation system.

[0040] The specific embodiments described above are presented as examples, and it should be understood that there is room for various modifications and alternative forms of these embodiments. Furthermore, it should be understood that the claims are not intended to be limited to the specific forms disclosed, but rather to encompass all modifications, equivalents, and alternatives that fall within the spirit and scope of this disclosure.

[0041] The technologies presented and claimed herein relate to tangible objects and specific examples of a practical nature that clearly improve the art, and apply to such tangible objects and specific examples; they are not abstract, intangible, or merely theoretical. Furthermore, if any claim attached to the end of this specification contains one or more elements designated as “means for performing [a function]” or “steps for performing [a function],” such elements are intended to be construed under 112(f) of the U.S. Patent Act. However, with respect to any claim containing elements designated in any other way, such elements are not intended to be construed under 112(f) of the U.S. Patent Act. [Explanation of symbols]

[0042] 10 Gas Turbine Systems 12 loads 14 Air 15 Fuel 16 Combustor 18 Compressed air stream 20 Compressors 26 High-temperature combustion gases 28 Gas Turbine 30 Drive shaft 32 Exhaust gas 34 Exhaust Section 36 Catalyst section 38 Controllers 39 Prediction Circuit 42 Generators 44 motors 48 Gas turbine generator 50 Gas Turbine Systems 52 Gas turbine engine 54 Gas turbine engine 66 processors 68 memory 76 Air intake 78 Air intake 80 Air compressor 82 Air compressor 88 Combustor 90 Combustor 92 Gas Turbine 94 Gas Turbine 96 load 98 load 120 Graphs 124 Minimum threshold frequency 150 processes 190 Graphs 192 lines 194 Pre-start period 196 lines 198 Preemphasis period 200 lines 202 Start-up period 204 line 206 Post-start period

Claims

1. AC motor and, One or more gas turbine generators (48) configured to supply power to the AC motor, It is determined that the AC motor can be started using the aforementioned power. When it is determined that the AC motor can be started using the power, the power is increased prior to the starting of the AC motor, and The enhanced power is used to compensate in advance for the decrease in the electrical parameters of the power caused by the increased demand for starting the AC motor. The increased power is reduced after the AC motor has finished starting up. A controller (38) configured to control the operation of one or more gas turbine generators (48) and Equipped with, Increasing the power includes starting an additional generator (42), Reducing the increased power includes stopping the additional generator (42), system.

2. The system according to claim 1, wherein determining that the AC motor is to be started includes receiving a schedule for starting the AC motor.

3. The system according to claim 1, wherein the electrical parameters include the frequency of the power.

4. The system according to claim 3, wherein increasing the power includes increasing the frequency.

5. The system according to claim 1, wherein the electrical parameters include the voltage of the power.

6. The system according to claim 5, wherein increasing the power includes increasing the voltage.

7. The system according to claim 1, wherein the amount of torque applied to the AC motor from energy derived from a generator in order to increase the angular momentum of the AC motor from an initial state of no angular momentum is greater than the amount of torque applied to the AC motor in order to maintain the angular momentum of the AC motor at a constant finite value.

8. The system according to claim 1, wherein the controller (38) includes a prediction circuit configured to determine when the AC motor can be started and to increase the power.

9. An AC motor and A turbine generator (48) configured to supply power to the AC motor, Regarding the AC motor, the determination is made that a rapid increase in demand for power from the turbine generator (48) is scheduled, and that the scheduled rapid increase in demand includes the starting of the AC motor. With respect to the AC motor, when it is determined that the rapid increase is scheduled, one or more modes of power are increased in advance by bringing additional gas turbine generators online prior to the rapid increase in the scheduled demand. Using the enhanced one or more modes of the power, to preemptively compensate for a decrease in one or more modes of the power caused by a sudden increase in scheduled demand, To reduce one or more of the enhanced power after the AC motor has finished starting up, A controller (38) configured to perform the following: Equipped with, A system in which reducing one or more of the augmented modes of the power includes taking the further gas turbine generators offline.

10. The system according to claim 9, wherein the starting includes a bump start of the AC motor in a state where there is no initial inertial motion of the AC motor.

11. The system according to claim 9, wherein reducing one or more of the power comprises reducing the one or more of the power back to the level before enhancement.

12. The system according to claim 9, wherein one or more of the above embodiments include the frequency or voltage of the power.

13. The system according to claim 9, further comprising one or more additional loads (12) that receive the power from the turbine generator (48).

14. The system according to claim 9, wherein the amount of torque applied to the AC motor from energy derived from a generator in order to increase the angular momentum of the AC motor from an initial state of no angular momentum is greater than the amount of torque applied to the AC motor in order to maintain the angular momentum of the AC motor at a constant finite value.

15. A tangible, non-temporary computer-readable medium storing instructions, wherein the instructions, when executed by the processor (66), To manage the operation of a gas turbine generator and generate electricity. To determine that the motor will be started according to the scheduled start, Prior to starting the motor, increase at least one parameter of the power to be generated, and To compensate in advance for the decrease in the at least one parameter, the motor is started using the increased at least one parameter of the generated power. The increased power is reduced after the motor has finished starting up. It is configured to cause the processor (66) to execute the following: Increasing the power includes starting an additional generator (42), Reducing the increased power includes shutting down the additional generator (42) in a tangible, non-temporary, computer-readable medium.

16. When the aforementioned instruction is executed by the processor, The motor determines that it has reached its operating speed, and By taking the additional generator offline, the at least one parameter can be reduced. A tangible, non-temporary, computer-readable medium according to claim 15, configured to cause the processor to perform the following.

17. A tangible, non-temporary, computer-readable medium according to claim 15, wherein the amount of torque applied to the motor from energy derived from a gas turbine generator to increase the angular momentum of the motor from an initial state of no angular momentum is greater than the amount of torque applied to the motor to maintain the angular momentum of the motor at a constant finite value.

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