Patent Application
20100281843
The subject matter disclosed herein relates to fault detection and protection of compressors.
Compressors are used in a variety of industries and systems to compress a gas, such as air. For example, gas turbine engines typically include a compressor to provide compressed air for combustion and cooling. As appreciated, the health of the compressor affects performance, efficiency, downtime, and overall availability of the machine. If compressor components (e.g., blades, seals, etc.) wear or break, then the compressor may not provide sufficient compression of the gas (e.g., air) to the target system (e.g., gas turbine engine). Furthermore, breakage of compressor components may cause damage to the target system (e.g., gas turbine engine), thereby leading to downtime and increased repair costs. This is particularly problematic for power plants, which rely on continuous operation of gas turbine engines. As a result, it is desirable to identify faults at an early stage to protect the compressor and downstream gas turbine engine components from damage. Unfortunately, existing systems are not particularly well suited for early detection of faults in compressors. This is particularly true with multi-stage compressors, such as those used in gas turbine engines in power plants. For example, existing systems do not monitor inter-stage regions of these multi-stage compressors.
Certain embodiments commensurate in scope with the originally claimed invention are summarized below. These embodiments are not intended to limit the scope of the claimed invention, but rather these embodiments are intended only to provide a brief summary of possible forms of the invention. Indeed, the invention may encompass a variety of forms that may be similar to or different from the embodiments set forth below.
In a first embodiment, a system includes an inter-stage sensor configured to sense a parameter at an inter-stage location between a plurality of stages of rotary blades of a rotary machine. The system also includes a controller configured to identify a fault in the rotary machine based at least in part on the sensed inter-stage parameter.
In a second embodiment, a system includes a controller configured to obtain an inter-stage pressure measurement between stages of a multi-stage compressor. The controller is also configured to identify actual damage in the multi-stage compressor based at least in part on the inter-stage pressure measurement.
In a third embodiment, a system includes a turbine engine. The turbine engine includes a compressor, a combustor, and a turbine expander. The compressor includes a plurality of compressor stages. The system also includes a plurality of inter-stage sensors configured to measure a plurality of parameters at inter-stage locations within the turbine engine. The system further includes a controller configured to identify a breakage in one of the compressor stages based at least in part on the plurality of parameters. The controller is also configured to output an alert indicative of the breakage, or automatically adjust an operating parameter of the turbine engine in response to the breakage, or automatically shut down the turbine engine in response to the breakage, or a combination thereof.
These and other features, aspects, and advantages of the present invention 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 present invention 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 present invention, 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. Any examples of operating parameters and/or environmental conditions are not exclusive of other parameters/conditions of the disclosed embodiments. Additionally, it should be understood that references to “one embodiment” or “an embodiment” of the present invention are not intended to be interpreted as excluding the existence of additional embodiments that also incorporate the recited features.
The disclosed embodiments include systems and methods for using inter-stage sensor measurements (e.g., pressure, temperature, acoustic, optical, and so forth) from a plurality of stages in a multi-stage rotary machine (e.g., compressors, turbines, and so forth) to identify faults within the multi-stage rotary machine. For simplicity, the multi-stage rotary machine disclosed herein will primarily be referred to as a multi-stage compressor. However, as appreciated, the systems and methods disclosed herein may also be utilized to identify faults in other types of rotary machines which include a plurality of stages.
During normal operation, each stage of the multi-stage compressor will generally increase the pressure and temperature of the working fluid by a certain amount. The amount of pressure and temperature increase at each stage of the multi-stage compressor may depend on particular operating conditions, such as speed, inlet boundary conditions (e.g., flow, pressure, temperature, composition, and so forth), outlet boundary conditions (e.g., flow resistance, and so forth), and stage efficiency. The overall pressure and temperature increase across the multi-stage compressor will generally be a summation of the pressure and temperature increases of the individual stages. Therefore, if one or more stages underperform, the state (e.g., pressure, temperature, and so forth) of the working fluid leaving the multi-stage compressor will be affected.
Ideally, the multi-stage compressor discharge measurements would be accurate enough to detect any deviation from expected or historical performance. However, since there may be hundreds or thousands of airfoils within the multi-stage compressor, a failure of one or a few of the individual airfoils may not change the overall performance of the multi-stage compressor significantly enough to rise above the level of measurement noise. Furthermore, the performance of the multi-stage compressor may vary considerably with operating conditions (e.g., guide vane position, inlet temperature and pressure, downstream resistance, and so forth) and may deteriorate over time (e.g., due to fouling, blade erosion, changes in clearance, and so forth), further complicating fault detection.
The disclosed embodiments address these difficulties by taking a different approach to multi-stage compressor fault detection. When a component is damaged or fails within the multi-stage compressor, the pressure and temperature distribution at each individual stage within the multi-stage compressor will also change. While the change in overall performance of the multi-stage compressor may not be readily detectable, the relative performance of each stage or group of stages may be more readily apparent and, thus, may provide a stronger indication of component damage or failure. The disclosed embodiments utilize sensor measurements (e.g., pressure, temperature, acoustic, optical, and so forth) at multiple locations within the multi-stage compressor (e.g., at least one inter-stage location in addition to the inlet and outlet of the multi-stage compressor). Deviations of these inter-stage sensor measurements from expected values may indicate that a fault has occurred in one of the stages. For simplicity, the inter-stage sensor measurements disclosed herein will primarily be referred to as pressure sensor measurements. However, as appreciated, the systems and methods disclosed herein may also include temperature sensor measurements, acoustic sensor measurements, optical sensor measurements, or any other type of sensor measurements which may indicate faults within multi-stage rotary machines, such as multi-stage compressors.
The increase in pressure between successive measurement locations may be compared to the overall increase in pressure across the multi-stage compressor, resulting in measured pressure increase ratios. These measured pressure increase ratios may be tracked as a function of any relevant set of operating conditions that would normally be expected to impact performance of the multi-stage compressor (e.g., shaft speed, guide vane position, inlet conditions, outlet conditions, and so forth). The measured pressure increase ratios may also be compared to expected pressure increase ratios as determined by modeling, measurement of other multi-stage compressors, or historical measurements of the same multi-stage compressor. If any of the measured pressure increase ratios deviate from the expected pressure increase ratios by more than a predetermined amount, an appropriate control response may be initiated, such as setting off an alarm, shutting down the multi-stage compressor, and so forth.
Alternatively, as described above, in certain embodiments, temperature measurements and temperature increase ratios may be used instead of or in conjunction with pressure measurements and pressure increase ratios. The choice between using pressure or temperature measurements may depend on measurement uncertainty and resultant fault detection sensitivity. In other words, if using pressure increase ratios for a particular multi-stage compressor leads to more reliable fault detection, the pressure increase ratios may be preferred over temperature increase ratios, and vice versa. In addition, in certain embodiments, comparison of both pressure and temperature increases for each multi-stage compressor section compared to other such sections may be beneficial instead of, or in addition to, comparison to the overall pressure and/or temperature increases across the multi-stage compressor.
In certain embodiments, the gas turbine engine 12 may mix compressed air with a liquid or gas fuel, such as natural gas and/or a hydrogen rich synthetic gas. As depicted, a plurality of fuel nozzles 24 intakes a fuel supply, mixes the fuel with air, and distributes the air-fuel mixture into a combustor 26. The air-fuel mixture combusts in a chamber within the combustor 26, thereby creating hot pressurized exhaust gases. The combustor 26 directs the exhaust gases through a turbine 20 toward an exhaust outlet 28. As the exhaust gases pass through the turbine 20, the gases force one or more turbine blades to rotate a shaft 30 along an axis 32 of the gas turbine engine 12. As illustrated, the shaft 30 is connected to various components of the gas turbine engine 12, including the multi-stage compressor 16. As described in greater detail below, the multi-stage compressor 16 may include multiple stages with multiple blades that may be coupled to the shaft 30. Thus, the multiple blades within the multi-stage compressor 16 rotate as the shaft 30 rotates, thereby compressing air from an air intake 34 through the multi-stage compressor 16 and into the fuel nozzles 24 and/or the combustor 26. The shaft 30 may also be connected to a load 36, which may be a vehicle or a stationary load, such as an electrical generator in a power plant or a propeller on an aircraft. The load 36 may include any suitable device configured to be powered by the rotational output of the gas turbine engine 12.
In certain embodiments, the fault detection and protection system 10 of
For example, as a comparison with the disclosed fault detection and protection system 10, fault monitoring would be particularly slow and space insensitive if sensors were located only at the compressor inlet 44 and the turbine outlet 56. Although these locations may be readily accessible for sensors, a significant amount of space would not be monitored without the sensors 42 and 50 between these inlet and outlet locations 44 and 56. In other words, if sensors were placed only at the inlet 44 and the outlet 56, then the changes would be averaged over the entire turbine engine 12, thereby making it difficult to identify a fault in either the compressor 16 or the turbine 20. A significant fault in one particular stage of the compressor 16 or the turbine 20 will cause a shift in temperature and/or pressure in that particular stage, yet the impact of this shift may be undetectable by sensors only at the inlet 44 and outlet 56. Likewise, if the compressor 16 is monitored only by sensors at the compressor inlet 44 and the compressor outlet 48, then the fault may not be readily detected due to a smaller perturbation of measurable exit conditions as compared to a more locally measurable impact. Furthermore, if the turbine 20 is monitored only by sensors at the turbine inlet 52 and the turbine outlet 56, then the fault may not be readily detected due to averaging over the multiple stages and/or compensatory control action as, for example, to maintain a selected output.
A common means of fault detection in rotating turbo-machinery is vibration monitoring at the bearings 58, 60. This means relies on the fact that a rotating blade has been damaged or has failed, causing a rotor imbalance. If the failed component is a stationary blade, there will generally be no detectable imbalance unless the liberated part damages downstream rotating blades enough to cause a detectable imbalance. Similarly, if the machine is large enough, and the failed rotating blade small enough, the problem may still be undetectable by this means. Consequently, a small problem will generally have to grow larger to be detectable via bearing vibration (e.g., due to collateral damage to downstream parts) before the control or operator becomes aware that protective action is needed. In addition, if and when a fault is detected by this means, the diagnostic information available from the vibration signature may only provide crude guidance regarding the location of the fault and its progression history. In general, the foregoing measurements at limited locations (i.e., not inter-stage) do not adequately detect faults at an early stage, thereby reducing the ability to take corrective measures before significant damage occurs.
Again, the disclosed embodiments of the fault detection and protection system 10 increase the sensitivity of fault detection in time and space by utilizing sensors at one or more inter-stage locations of the compressor 16, the turbine 20, or a combination thereof. In the following discussion, the fault detection and protection system 10 is discussed in context of the compressor 16, but it should be appreciated that the fault detection and protection system 10 is equally applicable to the turbine 20 and other multi-stage systems. At various inter-stage locations 46 and 54, the sensors 42 and 50 may monitor pressure, temperature, vibration, acoustics, or a combination thereof. These measured parameters may be compared with other stages (i.e., upstream and/or downstream), the inlets 44 and 52, the outlets 48 and 56, or a combination thereof. For example, the disclosed embodiments may compare baseline ratios with real-time ratios to identify abnormalities indicative of a fault. The ratios may include an inter-stage parameter versus an inlet parameter, an inter-stage parameter versus an outlet parameter, a first inter-stage parameter versus a second inter-stage parameter, or a combination thereof. Again, the parameters may include temperature, pressure, vibration, acoustics, or a combination thereof.
As described above, in certain embodiments, the inlet sensor 62, the outlet sensor 64, and the plurality of inter-stage sensors 66 may include pressure sensors, temperature sensors, vibrations sensors, acoustic sensors, optical sensors, flow rate sensors, and so forth. In the presence of a failure or other type of damage within a particular stage, both the pressure and temperature increase across the stage experiencing the damage may be drastically affected. Indeed, if the failure is severe enough, the pressure and temperature increases across the stage experiencing the failure may be reduced to zero or at least a negligible amount. For example, the pressure drop and temperature rise may change by at least greater than 10, 20, 30, 40, 50, 60, 70, 80, 90, or even 100% of an expected value. As such, monitoring inter-stage pressures and temperatures will enable detection of faults within the multi-stage compressor 16 more readily. In other words, while the change in overall performance of the multi-stage compressor 16 may not be readily detectable due to a failure in one or a few stages, the relative performance of each stage or group of stages will be more apparent and will provide a stronger indication of a component damage or failure.
Pressure and temperature measurements are not the only type of inter-stage measurements which may be used to detect faults within the multi-stage compressor 16. For example, in certain embodiments, acoustic sensors may be used for the inter-stage sensors 66. Faults may also be detected using sound signatures within each of the individual stages of the multi-stage compressor 16. In addition, in other embodiments, optical sensors may be used for the inter-stage sensors 66. Light variations detected by the optical sensors may indicate variations in the flow of the working fluid through the multi-stage compressor 16, which may be indicative of faults within the multi-stage compressor 16. Furthermore, any type of sensors (e.g., vibration sensors, flow rate sensors, and so forth) which may indicate faults within the multi-stage compressor 16 may be used.
As illustrated, in the scenario where there has been a failure within the third stage of the multi-stage compressor 16, the pressure increase across the third stage of the multi-stage compressor 16 may be drastically reduced. To a certain degree, the other four stages may compensate for the loss in pressure across the third stage. For instance, the pressure increase across the first and second stages is illustrated as increasing from the first pressure profile 68 (e.g., normal operation) to the second pressure profile 70 (failure within the third stage). In addition, the pressure increase across the fourth and fifth stages is also illustrated as increasing from the first pressure profile 68 (e.g., normal operation) to the second pressure profile 70 (failure within the third stage).
In certain embodiments, the pressure increase across each stage of the multi-stage compressor 16 may be compared to the overall pressure increase across the multi-stage compressor 16. For example, assume that under normal conditions of the multi-stage compressor 16 depicted in
In addition to comparing the pressure increase across each stage of the multi-stage compressor 16 to the overall pressure increase across the multi-stage compressor 16, the pressure increase across each stage of the multi-stage compressor 16 may be compared to the pressure increase across itself during normal operations or may be compared to the pressure increase of other stages of the multi-stage compressor 16. This approach may magnify a measured change, making a component failure or damage more readily detectable. For example, as illustrated in
In addition to measuring and monitoring pressure increases across individual stages of the multi-stage compressor 16, pressure increases across other sections of the multi-stage compressor 16 may also be measured and monitored. A section may include multiple individual stages of the multi-stage compressor 16. For example, in the example depicted in
As described above, the first pressure profile 68 depicted in
Once it has been determined that the pressure increase ratio for a particular stage or section of stages has deviated (e.g., increased or decreased) from the expected pressure increase ratio for the stage or section of stages by more than a predetermined amount, an appropriate control response may be initiated. For example, under certain circumstances, an appropriate control response may be to alert an operator of the multi-stage compressor 16 that a pressure increase ratio has deviated from the expected pressure increase ratio by the predetermined amount. For example, the operator may be alerted when the deviation from the expected pressure increase ratio is only by a small amount or has only occurred for a short period of time. The alert may include an audio alert (e.g., beeping noise), vibration, light (e.g., from a light emitting diode), display message (e.g., on a display screen), email message, text message, and so forth. However, once the deviation from the expected pressure increase ratio either reaches a larger value or continues to occur for a longer period of time, operating parameters of the multi-stage compressor 16 may be automatically adjusted. For example, under certain circumstances, the multi-stage compressor 16 may be shut down in response to deviation from the expected pressure increase ratio.
As the number of stages within the multi-stage compressor 16 increases, the sensitivity of the fault detection using comparisons of pressure increase ratios may decrease somewhat. For example, although illustrated in
For example,
Therefore, as depicted in
At step 78, a fault in the multi-stage compressor 16 may be identified based at least in part on the sensed inter-stage parameter. The identified fault may include several different types of issues within the multi-stage compressor 16. For example, the fault may include an actual failure (e.g., a breakage or other physical and/or structural fault) of one of the components within the multi-stage compressor 16. However, the fault may also include other types of damage (e.g., blade unbalance and erosion, unacceptable friction due to changes in clearance, and so forth). As discussed above, the identification of the fault may include comparison of the sensed inter-stage parameter against predicted values (e.g., generated by a predictive model), historical values (e.g., prior operating data of the same multi-stage compressor 16 or another comparable multi-stage compressor 16), or a combination thereof.
At step 80, once the fault has been identified, an alert indicative of the fault may optionally be output. For example, the alert may include an audio alert (e.g., beeping noise), vibration, light (e.g., from a light emitting diode), display message (e.g., on a display screen), email message, text message, and so forth. In addition, at step 82, once the fault has been identified, operating parameters of the multi-stage compressor 16 may be optionally adjusted in response to the fault. In certain situations, the adjustment of the operating parameters of the multi-stage compressor 16 may be performed automatically in response to the fault. However, in other situations, the adjustment of the operating parameters of the multi-stage compressor 16 may be performed manually by an operator of the multi-stage compressor 16.
The adjustment of the operating parameters of the multi-stage compressor 16 may also vary between minimal adjustment (e.g., reducing the operating speed or load of the multi-stage compressor 16) to more drastic adjustment (e.g., shutting down the multi-stage compressor 16). The amount of adjustment performed may, for instance, depend upon the degree of deviation of the inter-stage parameter from an expected value. For example, if the deviation of the sensed inter-stage parameter from the expected value is greater than a first, lower threshold value but less than a second, higher threshold value, the operating speed or load of the multi-stage compressor 16 may be reduced. However, if the deviation of the sensed inter-stage parameter from the expected value is greater than both the first, lower threshold value and the second, higher threshold value, the multi-stage compressor 16 may be completely shut down.
In addition, in certain embodiments, there may be a time delay between identifying the fault and either outputting alerts or adjusting operating parameters of the multi-stage compressor 16. For example, in certain embodiments, a time delay of 5, 10, 15, or 20 minutes may be used in order to confirm that the deviations in the sensed inter-stage parameter which identified the fault were not merely statistical aberrations. In other embodiments, no time delay may be used. Not using a time delay may prove beneficial for enabling an appropriate response in substantially real-time. In addition to time delays, in certain embodiments, multiple alerts may be outputted before operating parameters of the multi-stage compressor 16 are adjusted. Outputting multiple alerts may allow further analysis to be performed before operating parameters of the multi-stage compressor 16 are adjusted, either automatically or manually.
Technical effects of the disclosed embodiments include providing systems and methods for identifying faults within the multi-stage compressor 16 using pressure increase ratios, which may be determined from inter-stage parameters sensed between stages of the multi-stage compressor 16. In certain embodiments, the method 74 illustrated in
The embodiments disclosed herein provide for instrumentation of the individual stages of the multi-stage compressor 16 and an associated control strategy for detecting anomalous behavior in the multi-stage compressor 16 at or near the onset of a problem, such that the controller 14 may issue an alarm and/or adjust operating parameters of the multi-stage compressor 16 prior to excessive damage to the multi-stage compressor 16. The disclosed embodiments take advantage of the fact that when a stage of the multi-stage compressor 16 experiences damage, the performance of the stage decreases. The performance decrease may be manifested as a shift in the compression duty from the damaged stage to the other undamaged stages. This shift may be detected in the pressure distribution within the multi-stage compressor 16. Using pressure increase ratios for fault detection may facilitate more refined degradation assessment for the multi-stage compressor 16, thereby reducing the cost and downtime associated with unwanted damage to the multi-stage compressor 16. The systems and methods disclosed herein may be applied to new gas turbine engines 12 or may be retrofitable as enhancements to the instrumentation and control systems of existing gas turbine engines 12.
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.
