Patent Application
20180253087
The present disclosure relates generally to power generation systems. In particular, the present disclosure relates to scheduling maintenance operations of a power generation system to reduce degradation of the power generation system.
Degradation of a power generation system (e.g., a gas turbine system) occurs when one or more operating parameters of the power generation system degrades over time. For example, the compressor of the power generation system may degrade (e.g., decrease) under the same or similar operating and ambient conditions over a period of time (e.g., months, years, and the like) of operating the power generation system. This may be because components of the power generation system may degrade or otherwise change from use and time. For example, the compressor may collect deposits, erode, break down, and the like.
Degradation may be reduced or recovered from by performing maintenance operations on the power generation system. For example, components may be cleaned, flushed, refurbished, replaced, and the like. However, performing a maintenance operation may involve shutting down the power generation system and ceasing production by the power generation system. As such, costs (e.g., from lost profits, lost opportunities, maintenance materials, labor costs, component replacement, restart fuel, and the like) that result from shutting down the power generation system may begin accruing and increasing while the power generation system is shutdown. At the same time, operating the power generation system when it is in a degraded condition accrues its own costs due to less efficient power production. In some cases, if a maintenance operation is not performed at an appropriate time, excessive costs resulting from reduced power production and/or conversion efficiency due to operation of an excessively degraded power generation system may be realized. Similarly, if the maintenance operation is performed too soon or before the costs of operating the power generation system at reduced power output and/or efficiency is greater than some threshold, excessive costs resulting from performing a largely superfluous maintenance operation on an insufficiently degraded power generation system may be realized as compared to performing the maintenance operation at a later time (e.g., when the power generation system is more degraded).
Certain embodiments commensurate in scope with the original claims are summarized below. These embodiments are not intended to limit the scope of the claimed embodiments, but rather these embodiments are intended only to provide a brief summary of possible forms of the systems and techniques disclosed herein. Indeed, the presently claimed embodiments may encompass a variety of forms that may be similar to or different from the embodiments set forth below.
In one embodiment, a system includes a power generation system. The system also includes controllers that control operations of the power generation system. The controllers include processors that receive multiple values associated with operating parameters of the power generation system from sensors disposed within the power generation system. The processors also determine a degradation cost function that quantifies a degradation cost of the power generation system over an operating time of the power generation system based on the values. The processors further receive an operation cost of the power generation system that includes a fixed financial cost of performing an operation on the power generation system. The processors also determine an operation cost function that quantifies the operation cost in relation to the operating time of the power generation system. The processors further determine a total cost function of the power generation system over the operating time of the power generation system based on the degradation cost function and the operation cost function. The processors also determine times to perform the operation on the power generation system based on the total cost function. The processors further send an alert to perform the operation of the power generation system at the times.
In another embodiment, a method includes receiving, via processors, multiple values associated with operating parameters of a power generation system from sensors disposed within the power generation system. The method also includes determining, via the processors, a degradation cost function that quantifies a degradation cost of the power generation system over an operating time of the power generation system based on the values. The method further includes receiving, via the processors, an operation cost of the power generation system that includes a fixed financial cost of performing an operation on the power generation system. The method also includes determining, via the processors, an operation cost function that quantifies the operation cost in relation to the operating time of the power generation system. The method further includes determining, via the processors, a total cost function of the power generation system over the operating time of the power generation system based on the degradation cost function and the operation cost function. The method also includes determining, via the processors, times to perform the operation on the power generation system based on the total cost function. The method further includes scheduling, via the processors, the operation of the power generation system at the times.
In yet another embodiment, a tangible, non-transitory, machine-readable-medium, includes machine-readable instructions to cause processors to receive multiple values associated with operating parameters associated with a power generation system from sensors disposed within the power generation system. The machine-readable instructions also cause the processors to determine a degradation cost function that quantifies a degradation cost of the power generation system over an operating time of the power generation system based on the values. The machine-readable instructions further cause the processors to receive an operation cost of the power generation system that includes a fixed financial cost of performing an operation on the power generation system. The machine-readable instructions also cause the processors to determine an operation cost function that quantifies the operation cost in relation to the operating time of the power generation system over the operating time of the power generation system. The machine-readable instructions further cause the processors to determine a total cost function of the power generation system over the operating time of the power generation system based on the degradation cost function and the operation cost function. The machine-readable instructions also cause the processors to determine times to perform the operation on the power generation system based on the total cost function. The machine-readable instructions further cause the processors to send an instruction to perform the operation of the power generation system at the times.
These and other features, aspects, and advantages of the presently disclosed techniques will become better understood when the following detailed description is read with reference to the accompanying drawings in which like characters represent like parts throughout the drawings, wherein:
One or more specific embodiments of the presently disclosed embodiments will be described below. In an effort to provide a concise description of these embodiments, all features of an actual implementation may not be described in the specification. It should be appreciated that in the development of any such actual implementation, as in any engineering or design project, numerous implementation-specific decisions must be made to achieve the developers' specific goals, such as compliance with system-related and business-related constraints, which may vary from one implementation to another. Moreover, it should be appreciated that such a development effort might be complex and time consuming, but would nevertheless be a routine undertaking of design, fabrication, and manufacture for those of ordinary skill having the benefit of this disclosure.
When introducing elements of various embodiments of the presently disclosed embodiments, the articles “a,” “an,” “the,” and “said” are intended to mean that there are one or more of the elements. The terms “comprising,” “including,” and “having” are intended to be inclusive and mean that there may be additional elements other than the listed elements.
Degradation of a power generation system (e.g., a gas turbine system) may be assessed and estimated via modeling. The estimated degradation of the power generation system may be combined with economical and operational (e.g., cost) data of the power generation system to determine times to schedule and perform maintenance of the power generation system. As such, costs from operating a degraded power generation system may be balanced with costs of performing a maintenance operation that reduces degradation of the power generation system, thereby reducing a total cost to an operator of the power generation system.
In one embodiment, controllers of a power generation system may determine a degradation cost function that quantifies a degradation cost of the power generation system over time. The controllers may also determine a maintenance operation cost function that quantifies the maintenance operation cost of the power generation system based on a total operating time of the power generation system over time. The controllers may then determine a total cost function of the power generation system over time based on the degradation cost function and the maintenance operation cost function. The controllers may then schedule a maintenance operation of the power generation system based on the total cost function. In this manner, costs from operating a degraded power generation system may be balanced with costs of performing the maintenance operation that reduces degradation of the power generation system, reducing a total cost to an operator of the power generation system.
While the present disclosure discusses embodiments associated with a gas turbine system, it should be understood that the systems and methods described in the present disclosure may apply to any suitable power generation system, such as a steam turbine system, wind turbine system, hydroturbine system, combustion engine, hydraulic engine, electric generator, and the like.
The operation of the gas turbine system 10 may be monitored by one or more sensors 28 that may detect various observable conditions of one or more components of the gas turbine system 10 (e.g., the generator 26, the intake 21, etc.) and/or the ambient environment. In some embodiments, multiple redundant sensors may measure the same measured condition. For example, multiple redundant temperature sensors 28 may monitor ambient temperature surrounding the gas turbine system 10, compressor discharge temperature, turbine exhaust gas temperature, and other temperature measurements of the gas stream through the gas turbine system 10. Similarly, multiple redundant pressure sensors 28 may monitor ambient pressure, and static and dynamic pressure levels at the intake duct 21, exhaust duct 24, and/or at other locations in the gas stream through the gas turbine system 10. Multiple redundant humidity sensors 28 (e.g., wet and/or dry bulb thermometers) may measure ambient humidity in the intake duct 21. The redundant sensors 28 may also include flow sensors, speed sensors, flame detector sensors, valve position sensors, guide vane angle sensors, or the like, that sense various parameters pertinent to the operation of gas turbine system 10.
As used herein, a “parameter” refers to a measurable and/or estimable quality that can be used to define an operating condition of the gas turbine system 10, such as temperature, pressure, gas flow, or the like, at defined locations in the gas turbine system 10. Some parameters are measured (i.e., sensed) and are directly known. Other parameters are estimated by a model and are indirectly known. The measured and estimated parameters may be used to represent a given turbine operating state.
The controller 18 may include one or more computer systems and/or platforms having one or more processors 19 (e.g., a microprocessor(s)) that may execute software programs to control the operation of the gas turbine system 10 using sensor inputs and instructions from human operators. Moreover, the processor(s) 19 may include multiple microprocessors, one or more “general-purpose” microprocessors, one or more special-purpose microprocessors, and/or one or more application specific integrated circuits (ASICS), or some combination thereof. For example, the processor(s) 19 may include one or more reduced instruction set (RISC) processors. The controller 18 may couple to one or more memory devices 20 that may store information such as control software, look up tables, configuration data, etc. In some embodiments, the processor(s) 19 and/or the memory device(s) 20 may be external to the controller 18. The memory device(s) 20 may include a tangible, non-transitory, machine-readable-medium, such as a volatile memory (e.g., a random access memory (RAM)) and/or a nonvolatile memory (e.g., a read-only memory (ROM), flash memory, a hard drive, or any other suitable optical, magnetic, or solid-state storage medium, or a combination thereof). The memory device(s) 20 may store a variety of information and may be used for various purposes. For example, the memory device(s) 20 may store machine-readable and/or processor-executable instructions (e.g., firmware or software) for the processor(s) 19 to execute, such as instructions for scheduling maintenance of the gas turbine system 10.
While the present disclosure refers to a single controller 18, it should be understood that the controller 18 may include multiple controllers, computer systems, and/or computer platforms. For example, a first controller may control the gas turbine 16 (e.g., performing control functions including collecting sensor information), while a second controller may be a separate computer platform from the first controller and perform data analysis associated with the gas turbine 16 (e.g., characterizing degradation, performing the economic analysis, gathering user inputs on costs, providing analysis results, and the like). In such an example, the second controller may communicate with the first controller to receive the sensor information. Both the first controller and the second controller may be collectively referred to as the single controller 18 in the present disclosure.
The controller 18 may receive (process block 42) values associated with one or more operating parameters of the gas turbine system 10 over time (e.g., over an operating time of the gas turbine system 10). The one or more operating parameters may include, but are not limited to, compressor inlet airflow, fuel flow, rotational speed, generator or power output, exhaust temperature (e.g., turbine exhaust temperature), compressor condition (e.g., compressor pressure ratio), and the like. The values may be provided by one or more sensors of the gas turbine system 10.
The controller 18 may then determine (process block 44) a degradation cost function that quantifies a degradation cost of the gas turbine system 10 over an operating time of the gas turbine system 10 based on the values. The degradation cost is a cost of decreased power production and/or efficiency of the gas turbine system 10 resulting from degrading operating parameters of the gas turbine system 10, including the one or more operating parameters referred to in process block 42.
That is, the controller 18 may generate or use a model of the gas turbine system 10 to model flow and/or efficiency of the compressor 12 (e.g., compressor flow and/or efficiency loss) of the gas turbine system 10. For example, the controller 18 may receive discharge pressure and/or temperature measurements of the compressor 12 using sensors 28. The controller 18 may also use the model to generate corresponding modeled discharge pressure and/or temperature of the compressor 12. The controller 18 may adjust the modeled compressor flow and/or efficiency (via multipliers applied to the modeled compressor flow and/or efficiency) such that modeled discharge pressure and/or temperature output by the model approximately match the measured discharge pressure and/or temperature.
Additionally, the controller 18 may track historical data or values of the compressor flow and/or efficiency loss over time, and generate a transfer function to correlate the compressor flow and/or efficiency loss to operational time (and potentially other operational and/or ambient factors). The transfer function may be a linear, quadratic, or other fit function, based on the historical data. Using the transfer function, the controller 18 may estimate, predict, forecast, or otherwise determine compressor flow and/or efficiency loss at any point in time. The controller 18 may also use the gas turbine model to predict power production and/or efficiency loss (e.g., the degradation cost function) of the gas turbine system 10 as the result of the compressor flow and/or efficiency loss. Factoring in market prices for electricity and fuel, the power and efficiency loss (e.g., the degradation) of the gas turbine system 10 may be computed into financial cost terms. For example, a net profit from operating the gas turbine system 10 may be a difference between a gross profit from operating the gas turbine system 10 and an operational cost of operating the gas turbine system 10. The gross profit may be a product of power production of the gas turbine system 10 and an electricity market price. The operational cost may be a product of a fuel consumption of the gas turbine system 10 and a fuel market price. Using these financial relationships, an economic impact of the power production and/or efficiency loss of the gas turbine system 10 is financially quantifiable. Integration of the degradation cost function over time may then be divided by a total operating time to determine an average degradation cost of a given time period.
For example, compressor may degrade (e.g., decrease) under the same or similar operating and ambient conditions over a period of time (e.g., months, years, and the like) due to normal wear. This may be because components of the gas turbine system 10 may degrade or otherwise change from use and time. For example, the compressor of the power generation system may change, collect deposits, erode, and the like.
The controller 18 may determine the degradation cost function by determining degradation of the one or more operating parameters over the operating time of the gas turbine system 10. For example, the controller 18 may generate a model of the gas turbine system 10. The model may simulate the one or more operating parameters of the gas turbine system 10. The model may also include one or more inputs corresponding to one or more inputs to the gas turbine system 10. The input(s) to the gas turbine system 10 may include, for example, and without limitation, fuel flow rate, ambient conditions, angle of the inlet guide vanes 22, amount of fuel flowing to the combustion system 14, rotational speed of the gas turbine system 10, and the like. By way of example,
The controller 18 may input values associated with the operating parameter(s) 72 and values associated with the modeled operating parameter(s) 74 to an error correction system or filter 76 (e.g., a Kalman filter gain matrix) that automatically and regularly adjusts or tunes the model 70 (e.g., by tuning the input(s) 80 to the model 70) to more accurately fit the values associated with the modeled operating parameter(s) 74 to the values associated with the operating parameter(s) 72. In some embodiments, the filter 76 may use partial derivative analysis and/or normalization to determine a matrix of tuning or gain values to be applied to the values associated with the modeled operating parameter(s) 74. For each set of values, the filter 76 may generate one or more adjustments 78 based on a difference between a respective value of the modeled operating parameter(s) 74 and a respective value of the operating parameter(s) 72. The one or more adjustments 78 may be applied to the model 70 such that the values associated with the modeled operating parameter(s) 74 approximately matches the values associated with the operating parameter(s) 72.
The resulting set of adjustments 78 may be used to determine an amount or quantify the degradation of the gas turbine system 10. For example, as the gas turbine system 10 degrades through use over time, adjustments 78 related to tuning values associated with a modeled compressor inlet airflow may increase to cause the values associated with the modeled compressor inlet airflow to match corresponding sensed or measured values associated with a compressor inlet airflow of the gas turbine system 10. The adjustments 78 may be used to generate a degradation function that may estimate degradation of the gas turbine system 10 at future times. For example, the controller 18, the model 70, and/or the filter 76 may determine the degradation function based on the adjustments 78. The controller 18 may then determine the degradation cost function by basing the degradation function on gas turbine operational time. For example, the degradation function may be divided by gas turbine operational time to realize the degradation cost function.
The following equation may express the degradation cost function (e.g., an amortized degradation cost function):
Amortized degradation cost=Average degradation cost rate×Time between maintenance operations (1)
where the amortized degradation cost is expressed in dollars, the average degradation cost rate is expressed in dollars per hour, and the time between washes is expressed in hours. The time between washes may include the operating time (in hours) of the gas turbine system 10.
The degradation cost rate may be derived from an empirical fit to historical degradation cost data. For example, the degradation rate (e.g., an instantaneous degradation rate) may be determined by analyzing power production (e.g., in megawatts) and/or heat rate (e.g., in British thermal units per kilowatt-hour) data (e.g., loss data) over time. The following equations may convert the degradation rate in terms of cost:
Instantaneous degradation cost rate=Instant profit ratetime=t−Instant profit ratetime=0 (2)
where the instantaneous degradation cost rate is expressed in dollars per hour, the instant profit rate at time t is expressed in dollars per hour, and the instant profit rate is expressed in dollars per hour. The following equation may determine the instant profit rate at time t:
Instant profit ratetime=t=Power productiontime=t×Electricity price−Power productiontime=t(3)×Heat Ratetime=t×Fuel price (3)
where the power production at time t is expressed in megawatts, the electricity price is expressed in dollars per megawatt-hour, the heat rate at time t is expressed in British thermal units per megawatt-hour, and the fuel price at dollars per British thermal unit. The degradation cost function (e.g., the amortized degradation cost) may be determined by integrating the instantaneous degradation cost rate from time=0 to time=t, and then dividing the result by time t.
An example of the degradation cost function is illustrated in
Returning to
The controller 18 may then determine (process block 48) a washing cost function that quantifies the washing cost of the gas turbine system 10 in relation to the operating time of the gas turbine system 10 over the operating time of the gas turbine system 10 between washes. In particular, the washing cost may be a fixed cost at a time the compressor water washing is performed. The fixed washing cost may then be amortized over a time between a previous compressor water washing and a current compressor water washing. While the washing cost is fixed when the compressor water washing is performed, the washing cost may vary over time. Because the washing cost, over time, may be a function of lost opportunity, and the lost opportunity may be a function of market electricity and fuel prices, both of which may vary over time, the washing cost may also vary over time.
For example, the longer the gas turbine system 10 operates between washes, the more production is realized by operating the gas turbine system 10, thus decreasing the relative washing cost. As such, the controller 18 may divide the washing cost by a total operating time of the gas turbine system between washes.
The following is an example of the washing cost function (e.g., an amortized wash cost):
Amortized wash cost=Washing cost/Time between washes (4)
where the amortized wash cost is expressed in dollars per hour, the washing cost is expressed in dollars, and the time between washes is expressed in hours.
Returning to
Returning to
As illustrated in
Returning to
Technical effects of the subject matter disclosed herein include, but are not limited to, scheduling maintenance operations of a gas turbine system 10 to reduce degradation of the gas turbine system 10. In particular, a controller 18 of the gas turbine system 10 may determine a degradation cost function that quantifies a degradation cost of the gas turbine system 10. The controller 18 may also determine a maintenance operation cost function that quantifies the maintenance operation cost of the gas turbine system 10 based on a total operating time of the gas turbine system 10 over time. The controller 18 may then determine a total cost function of the gas turbine system 10 over time based on the degradation cost function and the maintenance operation cost function. The controller 18 may then schedule a maintenance operation of the gas turbine system 10 based on the total cost function. In this manner, costs from operating a degraded gas turbine system 10 may be balanced with costs of performing the maintenance operation that reduces degradation of the gas turbine system 10, reducing a total cost to an operator of the gas turbine system 10.
This written description uses examples to describe the present embodiments, including the best mode, and also to enable any person skilled in the art to practice the presently disclosed embodiments, including making and using any devices or systems and performing any incorporated methods. The patentable scope of the presently disclosed embodiments 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.
