Control method and device for low-pressure blades of steam turbine

Abstract

The invention relates to the technical field of low-pressure blade control, in particular to a steam turbine low-pressure blade control method and device.The method comprises the steps that an exhaust steam temperature field of a steam turbine low-pressure cylinder is obtained through optical fibers and guide vanes, and the temperature difference and / or the temperature gradient are / is extracted; judging whether the temperature difference is greater than a first temperature threshold and whether the temperature gradient is greater than a second temperature threshold; if the temperature difference is larger than the first temperature threshold value, abnormity is determined, and a first control action of the turbine low-pressure blade is generated to eliminate abnormity; if the temperature gradient is larger than the second temperature threshold value, it is judged that abnormity exists, and a second control action of the turbine low-pressure blade is generated to eliminate the abnormity. Therefore, the problems of low safety and low measurement precision are solved; in addition, the compensation wire is easy to age and break in a vibration / high-temperature environment, and the maintenance cost is high. The steam turbine operation monitoring is faced with multiple challenges such as environment, technology, cost, operation and maintenance and the like.

Description

Technical Field

[0001] This application relates to the field of low-pressure blade control technology, and in particular to a control method and device for low-pressure blades of steam turbines. Background Art

[0002] In related technologies, an invasive installation method can be adopted, in which a sheathed thermocouple is fixed to the measuring point by welding or thread sealing through a mechanical hole in the exhaust cylinder wall. Based on the Seebeck effect, the local temperature is converted into a millivolt-level electrical signal, which is transmitted to the control room via a compensating wire to achieve digital acquisition of single-point temperature. Alternatively, a wideband infrared detector can be fixed to the axial side of the last stage blade of the steam turbine through a support, and temperature data can be acquired by a computer.

[0003] However, among related technologies, invasive temperature measurement technology damages the cylinder structure, threatening equipment safety under high temperature and high pressure conditions; single-point measurement is difficult to characterize the temperature field distribution across the entire exhaust cylinder, and heat conduction loss leads to systematic errors, thus reducing measurement accuracy; in addition, compensation wires are prone to aging and breakage in vibration / high temperature environments, increasing maintenance costs; infrared technology faces multiple challenges in terms of environment, technology, cost, and operation and maintenance, and urgently needs improvement. Summary of the Invention

[0004] This application provides a control method and device for low-pressure blades of a steam turbine to address the following issues in related technologies: invasive temperature measurement technology has low safety and low measurement accuracy; in addition, compensating wires are prone to aging and breakage in vibration / high-temperature environments, increasing maintenance costs; and infrared technology faces multiple challenges in steam turbine operation monitoring, including environmental, technical, cost, and operation and maintenance aspects.

[0005] The first aspect of this application provides a low-pressure cylinder for a steam turbine, including an exhaust passage and a first guide ring and a second guide ring disposed within the exhaust passage, and further including: at least one guide vane, the guide vane being disposed between the first guide ring and the second guide ring, and the guide vane being provided with at least one optical fiber.

[0006] Through the above technical solution, a guide vane can be set between the first guide ring and the second guide ring, and an optical fiber can be set on the guide vane. Through the integrated structure of the guide vane and the upper and lower guide rings and the direct thermal coupling design between the optical fiber and the vane, the temperature conduction efficiency is improved, and the transient temperature fluctuation of the guide vane can be captured in real time.

[0007] Optionally, in one embodiment of this application, at least one optical fiber groove is formed on the guide vane, and the optical fiber is disposed in the optical fiber groove; at least a portion of the optical fiber groove extends along the exhaust direction.

[0008] The above technical solution allows optical fibers to be placed inside an optical fiber slot and extended along the exhaust direction, avoiding direct scouring by solid particles in the steam, reducing the wear rate of the optical fiber embedded in the slot, improving the stability of the optical fiber signal, and increasing the thermal contact area between the optical fiber and the main steam flow area by extending the optical fiber slot along the exhaust direction, thus shortening the response time, reducing temperature measurement error, and improving the reliability of the measurement.

[0009] Optionally, in one embodiment of this application, the fiber optic groove is constructed as a closed loop, and the fiber optic groove is arranged circumferentially around the guide vane.

[0010] The above technical solution can construct a micro-closed ring of fiber optic grooves and set them around the circumference of the guide vanes to realize the monitoring of the circumferential and axial temperature fields of the blade surface and surrounding flow field, and accurately locate the local overheating areas of the blade.

[0011] Optionally, in one embodiment of this application, the optical fiber slots are configured as a plurality of slots, which are arranged radially at intervals along the guide vanes, and the spacing between two adjacent optical fiber slots is 9%-15% of the height of the low-pressure cylinder of the steam turbine.

[0012] The above technical solution allows for the construction of multiple fiber optic slots, spaced radially along the guide vanes. The spacing between two adjacent slots is 9%-15% of the height of the low-pressure cylinder of the turbine. These radially spaced slots form a three-dimensional monitoring layer from the blade root to the middle and top, enabling precise real-time capture of the radial temperature gradient.

[0013] A second aspect of this application provides a control method for a low-pressure turbine blade, comprising the following steps: acquiring the exhaust temperature field of the low-pressure turbine cylinder using the optical fiber and the guide vanes, and extracting the temperature difference and / or temperature gradient in the exhaust temperature field; determining whether the temperature difference is greater than a first temperature threshold and whether the temperature gradient is greater than a second temperature threshold; if the temperature difference is greater than the first temperature threshold, determining that the low-pressure turbine blade is abnormal, and generating a first control action for the low-pressure turbine blade based on the difference between the temperature difference and the first temperature threshold to eliminate the abnormality according to the first control action; if the temperature gradient is greater than the second temperature threshold, determining that the low-pressure turbine blade is abnormal, and generating a second control action for the low-pressure turbine blade based on the difference between the temperature gradient and the second temperature threshold to eliminate the abnormality according to the second control action.

[0014] The above technical solution can extract the temperature difference and / or temperature gradient in the exhaust temperature field obtained by optical fiber and guide vanes, and determine whether the temperature difference is greater than a first temperature threshold and whether the temperature gradient is greater than a second temperature threshold. If the temperature difference is greater than the first temperature threshold, an anomaly is determined in the low-pressure turbine blade, and a first control action is generated to eliminate the anomaly. If the temperature gradient is greater than the second temperature threshold, an anomaly is determined in the low-pressure turbine blade, and a second control action is generated to eliminate the anomaly. This allows for real-time capture of transient temperature fluctuations in the blade, enabling full-domain circumferential and axial temperature field monitoring of the blade surface and surrounding flow field. It accurately locates local overheated areas of the blade, ensuring measurement stability and reliability, extending maintenance cycles, and providing direct, accurate, and long-lasting temperature monitoring assurance for the safe operation of the low-pressure blade.

[0015] Optionally, in one embodiment of this application, the step of obtaining the exhaust temperature field of the low-pressure cylinder of the steam turbine using the optical fiber and the guide vanes includes: converting the optical signal obtained from the optical fiber into a corresponding electrical signal; calculating temperature data at at least one measuring point in the optical fiber based on the Raman scattering principle and the electrical signal; and generating the exhaust temperature field based on the temperature data.

[0016] The above technical solution can convert the optical signal obtained from the optical fiber into a corresponding electrical signal, and then calculate the temperature data at different measuring points based on the Raman scattering principle, thereby generating the exhaust steam temperature field and realizing continuous distributed measurement. It can capture subtle gradient changes in the exhaust steam temperature field and achieve high-precision distributed temperature measurement. The optical fiber transmission is an optical signal, which is not affected by the strong electromagnetic field inside the steam turbine, thus improving the anti-electromagnetic interference capability of temperature measurement. The optical fiber is embedded inside or on the surface of the guide vane, which is simple to install, shortens the commissioning cycle, and reduces maintenance costs.

[0017] A third aspect of this application provides a control device for a low-pressure turbine blade, comprising: an extraction module for acquiring the exhaust temperature field of the low-pressure turbine cylinder using the optical fiber and the guide vanes, and extracting the temperature difference and / or temperature gradient in the exhaust temperature field; a judgment module for judging whether the temperature difference is greater than a first temperature threshold and whether the temperature gradient is greater than a second temperature threshold; a first generation module for determining that the low-pressure turbine blade is abnormal when the temperature difference is greater than the first temperature threshold, and generating a first control action for the low-pressure turbine blade based on the difference between the temperature difference and the first temperature threshold, so as to eliminate the abnormality according to the first control action; and a second generation module for determining that the low-pressure turbine blade is abnormal when the temperature gradient is greater than the second temperature threshold, and generating a second control action for the low-pressure turbine blade based on the difference between the temperature gradient and the second temperature threshold, so as to eliminate the abnormality according to the second control action.

[0018] The above technical solution can extract the temperature difference and / or temperature gradient in the exhaust temperature field obtained by optical fiber and guide vanes, and determine whether the temperature difference is greater than a first temperature threshold and whether the temperature gradient is greater than a second temperature threshold. If the temperature difference is greater than the first temperature threshold, an anomaly is determined in the low-pressure turbine blade, and a first control action is generated to eliminate the anomaly. If the temperature gradient is greater than the second temperature threshold, an anomaly is determined in the low-pressure turbine blade, and a second control action is generated to eliminate the anomaly. This allows for real-time capture of transient temperature fluctuations in the blade, enabling full-domain circumferential and axial temperature field monitoring of the blade surface and surrounding flow field. It accurately locates local overheated areas of the blade, ensuring measurement stability and reliability, extending maintenance cycles, and providing direct, accurate, and long-lasting temperature monitoring assurance for the safe operation of the low-pressure blade.

[0019] Optionally, in one embodiment of this application, the extraction module includes: a conversion unit for converting the optical signal obtained from the optical fiber into a corresponding electrical signal; a calculation unit for calculating temperature data at at least one measuring point in the optical fiber based on the Raman scattering principle and the electrical signal; and a generation unit for generating the exhaust temperature field based on the temperature data.

[0020] The above technical solution can convert the optical signal obtained from the optical fiber into a corresponding electrical signal, and then calculate the temperature data at different measuring points based on the Raman scattering principle, thereby generating the exhaust steam temperature field and realizing continuous distributed measurement. It can capture subtle gradient changes in the exhaust steam temperature field and achieve high-precision distributed temperature measurement. The optical fiber transmission is an optical signal, which is not affected by the strong electromagnetic field inside the steam turbine, thus improving the anti-electromagnetic interference capability of temperature measurement. The optical fiber is embedded inside or on the surface of the guide vane, which is simple to install, shortens the commissioning cycle, and reduces maintenance costs.

[0021] A third aspect of this application provides an electronic device, including: a memory, a processor, and a computer program stored in the memory and executable on the processor, wherein the processor executes the program to implement the control method for low-pressure turbine blades as described in the above embodiments.

[0022] A fourth aspect of this application provides a computer-readable storage medium storing a computer program that, when executed by a processor, implements the above-described method for controlling the low-pressure blades of a steam turbine.

[0023] A fifth aspect of this application provides a computer program product, including a computer program that, when executed, implements the control method for low-pressure turbine blades as described above.

[0024] This application embodiment can extract the temperature difference and / or temperature gradient in the exhaust temperature field obtained by optical fiber and guide vanes, and determine whether the temperature difference is greater than a first temperature threshold and whether the temperature gradient is greater than a second temperature threshold. Then, when the temperature difference is greater than the first temperature threshold, an anomaly is determined in the low-pressure blade of the steam turbine, and a first control action is generated to eliminate the anomaly; when the temperature gradient is greater than the second temperature threshold, an anomaly is determined in the low-pressure blade of the steam turbine, and a second control action is generated to eliminate the anomaly. It can capture transient temperature fluctuations of the blade in real time, realize the circumferential and axial full-domain temperature field monitoring of the blade surface and surrounding flow field, accurately locate the local overheated area of ​​the blade, ensure measurement stability and reliability, extend the maintenance cycle, and provide direct, accurate and lasting temperature monitoring guarantee for the safe operation of the low-pressure blade.

[0025] Additional aspects and advantages of this application will be set forth in part in the description which follows, and in part will be obvious from the description, or may be learned by practice of this application. Attached Figure Description

[0026] The above and / or additional aspects and advantages of this application will become apparent and readily understood from the following description of the embodiments taken in conjunction with the accompanying drawings, wherein:

[0027] Figure 1 This is a schematic diagram of the installation position of the guide vanes of a steam turbine low-pressure cylinder according to an embodiment of this application;

[0028] Figure 2 This is a block diagram of a fiber optic sensor array according to an embodiment of this application;

[0029] Figure 3 This is a block diagram illustrating the photoelectric conversion principle of optical fiber signals according to an embodiment of this application;

[0030] Figure 4 This is a flowchart of a control method for low-pressure turbine blades according to an embodiment of this application;

[0031] Figure 5 This is a flowchart illustrating the working principle of a control method for low-pressure turbine blades according to an embodiment of this application;

[0032] Figure 6 This is a block diagram of a control device for low-pressure turbine blades provided according to an embodiment of this application;

[0033] Figure 7 This is a schematic diagram of the structure of an electronic device provided according to an embodiment of this application.

[0034] Figure label:

[0035] Among them, 101-first guide ring, 102-second guide ring, 103-guide blade; 301-temperature sensing optical cable, 302-splitter, 303-sweep laser, 304-photoelectric conversion and data acquisition and analysis unit, 3041-frequency domain adjustment unit, 3042-time domain adjustment unit; 10-control device for low-pressure turbine blades, 100-extraction module, 200-judgment module, 300-first generation module, 400-second generation module; 701-memory, 702-processor, 703-communication interface. Detailed Implementation

[0036] The embodiments of this application are described in detail below. Examples of the embodiments are shown in the accompanying drawings, wherein the same or similar reference numerals denote the same or similar elements or elements having the same or similar functions throughout. The embodiments described below with reference to the accompanying drawings are exemplary and intended to explain this application, and should not be construed as limiting this application.

[0037] The control method and apparatus for low-pressure turbine blades according to embodiments of this application are described below with reference to the accompanying drawings. In view of the aforementioned background technologies, invasive temperature measurement technology suffers from low safety and measurement accuracy. Furthermore, compensating wires are prone to aging and breakage in vibration / high-temperature environments, increasing maintenance costs. Infrared technology faces multiple challenges in turbine operation monitoring, including environmental, technical, cost, and operational challenges. This application provides a control method for low-pressure turbine blades. In this method, the temperature difference and / or temperature gradient in the exhaust temperature field obtained from optical fibers and guide vanes can be extracted. It then determines whether the temperature difference exceeds a first temperature threshold and whether the temperature gradient exceeds a second temperature threshold. If the temperature difference exceeds the first temperature threshold, an anomaly is determined in the low-pressure turbine blade, and a first control action is generated to eliminate the anomaly. If the temperature gradient exceeds the second temperature threshold, an anomaly is determined in the low-pressure turbine blade, and a second control action is generated to eliminate the anomaly. This method can capture transient temperature fluctuations in the blade in real time, achieving full-domain circumferential and axial temperature field monitoring of the blade surface and surrounding flow field. It accurately locates local overheated areas of the blade, ensuring measurement stability and reliability, extending the maintenance cycle, and providing direct, accurate, and long-lasting temperature monitoring assurance for the safe operation of low-pressure blades. This solves the problems of low safety and low measurement accuracy of invasive temperature measurement technology; in addition, the compensating wires are prone to aging and breakage in vibration / high temperature environments, which increases maintenance costs; and the multiple challenges that infrared technology faces in turbine operation monitoring, including environmental, technical, cost and operation and maintenance issues.

[0038] Before introducing the control method for low-pressure turbine blades proposed in the embodiments of this application, the background technology of the embodiments of this application will be introduced.

[0039] Accurate measurement of the exhaust cylinder temperature field is crucial for optimizing unit efficiency and ensuring safe operation during steam turbine operation. Excessive temperature within the exhaust cylinder, coupled with continuous turbine operation, can lead to plastic deformation of the low-pressure blades. This not only significantly shortens blade lifespan but also poses a risk of rubbing due to changes in the clearance between moving and stationary components, thus threatening the safe operation of the steam turbine. Related temperature measurement technologies, such as thermocouples and resistance temperature detectors (RTDs), have significant limitations: single-point contact measurements can only obtain the temperature at discrete points on the exhaust cylinder wall, failing to cover the temperature distribution across the entire circumferential 360° and axial flow path. Actual measurement data shows that the exhaust cylinder temperature difference of a 300MW unit under variable load conditions can reach 25-35℃, and the probability of missing the local overheating in the eddy current region by single-point measurement exceeds 60%, which can easily lead to blade thermal stress concentration failure. The long heat conduction path results in a thermal response time of 5-10s. When a 600MW unit sheds load, the steam temperature changes rapidly at a rate of 12℃ / s. The lag measurement of relevant sensors will cause a control delay of about 8-15s, which directly affects the stability of the turbine speed control system. In the strong electromagnetic environment of the generator, the noise ratio of the electrical signal transmitted by the metal wire is >15dB. Related distributed temperature measurement solutions, such as infrared thermometry, are significantly constrained by the characteristics of the steam flow field: when the steam humidity inside the exhaust cylinder is >90%, the infrared signal with a wavelength of 8-14μm is attenuated by more than 85% due to scattering by water droplets, resulting in a measurement error of ±6-10℃ under 95% humidity conditions, and it is impossible to distinguish between cylinder wall and steam temperatures; its measurement relies on the emissivity of the object surface, but factors such as oxide layers and scale buildup on the exhaust cylinder wall cause dynamic changes in emissivity, requiring periodic shutdowns for calibration. Related technologies struggle to meet the high-precision temperature measurement requirements of ±1℃ under complex flow fields in the exhaust cylinder (such as vortex regions and throat contraction sections), leading to inaccurate judgment of stress changes in low-pressure blades and increasing the risk of blade thermal stress concentration failures.

[0040] Therefore, the embodiments of this application can infer the stress changes of the low-pressure blades through high-precision, real-time temperature monitoring, ensuring the safe operation of the blades. Six to twelve guide vanes are embedded on the upper and lower guide ring surfaces of the exhaust passage of the turbine's low-pressure cylinder, and optical fibers are grooved on the surface of the guide vanes. During operation, the optical fibers are fixed to the grooves on the blade surface using high-precision thermally conductive adhesive, forming a direct thermal coupling interface between the optical fibers, the guide vanes, and the surrounding steam flow field. The exhaust passage temperature is efficiently conducted to the optical fibers through the guide vanes, avoiding scattering interference from liquid droplets in the steam on the temperature measurement signal. This allows for high-precision, real-time measurement of the temperature field across the entire area of ​​the guide vane surface and surrounding region in complex flow fields, achieving high-precision, real-time measurement of the exhaust temperature field, thereby determining the stress changes of the low-pressure blades and ensuring their safe operation.

[0041] Specifically, Figure 1 This is a schematic diagram of the installation position of the guide vanes of a steam turbine low-pressure cylinder according to an embodiment of this application.

[0042] like Figure 1 As shown, the low-pressure cylinder of the steam turbine includes an exhaust passage and a first guide ring 101 and a second guide ring 102 disposed within the exhaust passage. It also includes at least one guide vane 103, which is disposed between the first guide ring 101 and the second guide ring 102, and has at least one optical fiber. At least one optical fiber groove is formed on the guide vane 103, and the optical fiber is disposed within the optical fiber groove. At least a portion of the optical fiber groove extends along the exhaust direction, and the optical fiber groove is constructed as a closed loop. The optical fiber groove is circumferentially arranged around the guide vane 103. Multiple optical fiber grooves are arranged radially spaced along the guide vane 103, with the spacing between two adjacent optical fiber grooves being 9%-15% of the height of the low-pressure cylinder of the steam turbine.

[0043] It is understood that the structural design of the guide vane 103 in this embodiment uses a high thermal conductivity alloy material of the same type as the exhaust cylinder. Its shape can be a fan-shaped structure, with 6-12 pieces embedded inside the first guide ring 101 (i.e., the upper guide ring) and the second guide ring 102 (i.e., the lower guide ring). The leading and trailing edge contours are optimized based on exhaust flow field simulation to minimize flow field disturbances when steam flows through, and to improve vortex conditions within the exhaust cylinder. An optical fiber groove adapted to the optical fiber size is formed on the surface of the guide vane 103. This groove can be a recess, and its upper and lower surfaces are tightly fitted to the first guide ring 101 or the second guide ring 102, fixed by welding, forming a carrier that combines heat conduction and flow field guidance functions. As a heat conduction medium, it rapidly and uniformly transfers the surface temperature of the guide vane 103 to the optical fiber. Simultaneously, the streamlined design optimizes steam flow and reduces vortex interference with temperature measurement.

[0044] It should be noted that in this embodiment, the optical fiber serves as both the sensing carrier (sensor body) for temperature signals and the transmission medium for optical signals; the two are integrated into a single design, eliminating the need for additional independent sensor components. This allows the optical fiber to directly form thermal coupling with the flow guide ring, efficiently transmitting temperature signals while avoiding interference from the steam flow field.

[0045] Furthermore, such as Figure 2As shown in the embodiment of this application, an embedded fiber optic sensor array is mounted on the guide vane 103. On the surface of each guide vane 103, 6-10 layers of annular array grooves are machined along the radial direction of the vane (from the root to the tip). The grooves encircle the vane to form a closed ring. The fiber optic sensor is embedded in this groove and fixed with high-temperature thermally conductive adhesive. The spacing between adjacent groove layers is set at 9%-15% of the exhaust cylinder height to ensure uniform distribution of each layer in the axial direction. This ultimately forms a multi-dimensional closed monitoring section within the entire exhaust channel, comprehensively covering areas prone to eddies (such as blade wakes and the throat of the exhaust channel), achieving full-domain capture of the temperature of the low-pressure blade surface and surrounding flow field. The fiber optic sensor uses distributed optical fiber with a temperature resistance of 600℃, based on the Raman scattering principle, with a spatial resolution of 0.1m, a temperature measurement accuracy of ±0.3℃, and a response time of <0.5s. It is preferentially arranged in the core eddy region. The optical fiber is fixed to the carrier by high-temperature brazing, and the surface is covered with a thick ceramic protective layer. The groove depth matches the outer diameter of the optical fiber to ensure a heat conduction efficiency of ≥90% while avoiding steam flow field disturbance.

[0046] Before introducing the control method for low-pressure turbine blades proposed in the embodiments of this application, the photoelectric conversion principle of optical fiber signals involved in the embodiments of this application will be explained first.

[0047] Specifically, Figure 3 This is a block diagram illustrating the photoelectric conversion principle of optical fiber signals according to an embodiment of this application.

[0048] like Figure 3 As shown, the conversion principle involves a temperature-sensing optical cable 301, a beam splitter 302, a frequency-sweeping laser 303, and a photoelectric conversion and data acquisition and analysis unit 304. The photoelectric conversion and data acquisition and analysis unit 304 includes a frequency domain adjustment unit 3041 and a time domain adjustment unit 3042.

[0049] Among them, the temperature-sensing optical cable 301 can directly sense the temperature change in the optical signal area when the temperature of the steam flow field in the exhaust cylinder is conducted to the optical fiber area through the guide ring.

[0050] Additionally, it should be noted that when laser light propagates in an optical fiber, it will produce Raman scattering in regions of temperature change, where the intensity ratio of anti-Stokes light to Stokes light changes linearly with temperature.

[0051] The beam splitter 302 is a key component of the optical link. It can distribute the picosecond-level swept laser pulses output by the swept laser 303 to the temperature-sensing optical cable 301 and separate the reverse-transmitted Raman scattered light. Then, the photoelectric conversion and data acquisition and analysis unit 304 can realize the bidirectional transmission and separation of optical signals.

[0052] The beam splitter 302 can be composed of two optical filters with different center wavelengths, which can filter out Stokes light and anti-Stokes light respectively.

[0053] The sweep laser 303 can generate picosecond-level sweep laser pulses.

[0054] The photoelectric conversion and data acquisition and analysis unit 304 uses a photodiode in conjunction with a narrowband filter to capture two optical signals in real time. After amplification, the optical signals are converted into an electrical pulse sequence through a high-speed sampling circuit. To suppress ambient light interference, the photoelectric conversion and data acquisition and analysis unit 304 is equipped with a gated integration circuit, which acquires signals only within a specific time window after the laser pulse emission. The acquired electrical pulse sequence is preprocessed by a digital signal processor. The preprocessing may include, but is not limited to, baseline correction and noise filtering, etc., which are not specifically limited in this application. The processed electrical signal is then transmitted to the temperature detection software. Through algorithm analysis and Raman scattering temperature measurement principles, the temperature can be calculated by detecting the intensity ratio. The calculation formula may be, but is not limited to, the following:

[0055]

[0056] Where T is temperature, I AS I S These are the intensities of anti-Stokes light and Stokes light, respectively, with K and C being calibration coefficients.

[0057] Furthermore, in this embodiment of the application, the spatial coordinates of the scattering point can be calculated by measuring the round-trip time of the laser pulse in the optical fiber, thereby determining the position of the point within the exhaust cylinder.

[0058] Furthermore, in this embodiment, the temperature of a given point can be calculated by measuring the ratio of the intensity of the anti-Stokes light to the intensity of the Stokes light at a specific spatial location, combined with a pre-calibrated "temperature-intensity ratio curve". The temperature measurement accuracy is ±0.5℃. This application does not impose any specific limitations.

[0059] Specifically, Figure 4 This is a flowchart of a control method for low-pressure blades of a steam turbine according to an embodiment of this application.

[0060] like Figure 4 As shown, the control method for the low-pressure blades of this steam turbine includes the following steps:

[0061] In step S401, the exhaust temperature field of the low-pressure cylinder of the steam turbine is obtained using optical fiber and guide vanes, and the temperature difference and / or temperature gradient in the exhaust temperature field are extracted.

[0062] It is understood that, in the embodiments of this application, accurate measurement of the exhaust temperature field is fundamental to assessing the stress changes of the low-pressure blades. Figure 1The optical fiber and guide vanes shown in this application embodiment can monitor the circumferential and axial temperature distribution of the exhaust cylinder in real time, and then extract the corresponding temperature difference and temperature gradient, quantify the non-uniformity of the temperature field, directly correlate with the assessment of the thermal stress risk of the low-pressure blade, thereby analyzing the thermal stress state of the low-pressure blade, and then issuing an early warning in time when the local temperature is too high or the temperature gradient is too large, so as to avoid the low-pressure blade from failing due to thermal stress concentration.

[0063] Among them, temperature difference can be understood as the temperature difference between different measuring points along the same axis or circumference (such as the difference between the highest and lowest temperatures of three measuring points, which is not specifically limited in this application), reflecting the temperature uniformity. The larger the difference, the more concentrated the thermal stress of the low-pressure blade.

[0064] Temperature gradient refers to the rate of temperature change (ΔT / Δheight, unit ℃ / m) between adjacent axial layers, reflecting the severity of axial temperature change. The larger the gradient, the more significant the difference in thermal expansion of the low-pressure blades along the height direction, which can easily induce axial stress.

[0065] Optionally, in one embodiment of this application, the exhaust temperature field of the low-pressure cylinder of the steam turbine is obtained using optical fiber and guide vanes, including: converting the optical signal obtained from the optical fiber into a corresponding electrical signal; calculating the temperature data at at least one measuring point in the optical fiber based on the Raman scattering principle and the electrical signal; and generating the exhaust temperature field based on the temperature data.

[0066] In some embodiments, the present application can be combined with Figure 3 As shown, when generating the exhaust temperature field using optical fiber and guide vanes, the optical signal obtained from the optical fiber is first converted into an electrical signal, and then the temperature data of the optical fiber at different measuring points is calculated based on the Raman scattering principle, thereby generating the exhaust temperature field.

[0067] In step S402, it is determined whether the temperature difference is greater than the first temperature threshold and whether the temperature gradient is greater than the second temperature threshold.

[0068] It is understood that in the embodiments of this application, the temperature difference reflects the temperature uniformity. The larger the difference, the more concentrated the thermal stress of the low-pressure blades. The temperature gradient reflects the severity of the axial temperature change. The larger the gradient, the more significant the difference in thermal expansion of the low-pressure blades along the height direction, which easily leads to axial stress.

[0069] Furthermore, this embodiment of the application sets certain thresholds and early warning mechanisms to ensure that alarms are issued in a timely manner when the low-pressure blade stress is abnormal, providing decision support for operators and ensuring the safe operation of the steam turbine.

[0070] In some embodiments, the present application can determine whether the temperature difference is greater than a first temperature threshold and whether the temperature gradient is greater than a second temperature threshold. The first and second temperature thresholds can be set by those skilled in the art according to actual conditions, and the present application does not impose specific limitations.

[0071] In step S403, if the temperature difference is greater than the first temperature threshold, it is determined that there is an abnormality in the low-pressure blade of the steam turbine, and a first control action of the low-pressure blade of the steam turbine is generated based on the difference between the temperature difference and the first temperature threshold, so as to eliminate the abnormality according to the first control action.

[0072] It is understood that in the embodiments of this application, the first control action may be to increase the water flow rate, reduce the load, or perform an emergency shutdown, etc. The specific settings can be made by those skilled in the art according to the actual situation, and this application does not impose any specific limitations.

[0073] In some embodiments, the present application can determine that there is an abnormality in the low-pressure blades of the steam turbine when the temperature difference is greater than a first temperature threshold, and then generate a first control action for the low-pressure blades based on different differences until the abnormality is eliminated.

[0074] In addition, in the embodiments of this application, the first temperature threshold can be set by comprehensively considering material properties, safety factor, historical fault data, and simulation model, and this application does not impose specific limitations.

[0075] For example, in this application embodiment, the first threshold can be set to 115℃. Then, when the temperature difference is greater than 115℃, the low-pressure blade is determined to be abnormal. The difference between the temperature difference and the first threshold is calculated. If the difference is between 0-10℃, the first control action is determined to be to increase the water spray flow rate, and the priority is low priority. If the temperature difference is between 10-20℃, the first control action is determined to be to reduce the load, and the priority is medium priority. If the temperature difference is greater than 20℃, the first control action is determined to be to shut down the machine, and the priority is high priority.

[0076] In step S404, if the temperature gradient is greater than the second temperature threshold, it is determined that there is an anomaly in the low-pressure blade of the steam turbine, and a second control action of the low-pressure blade of the steam turbine is generated based on the difference between the temperature gradient and the second temperature threshold, so as to eliminate the anomaly according to the second control action.

[0077] In some embodiments, the present application can determine that the low-pressure blade is abnormal when the temperature gradient is greater than a second temperature threshold, and then generate a second control action for the low-pressure blade based on the difference between the temperature gradient and the second temperature threshold, thereby eliminating the abnormality.

[0078] For example, in the embodiments of this application, if the temperature difference is greater than 0°C, the low-pressure blade is determined to be abnormal. Then, if the temperature difference is 0-3°C, the second control action is determined to be adjusting the spray valve opening; if the temperature difference is 3-6°C, the second control action is determined to be adjusting the load; and if the temperature difference is 6°C or above, the second control action is determined to be emergency shutdown.

[0079] Additionally, it should be noted that, in the absence of eliminating the anomaly, the embodiments of this application may employ a tiered warning mechanism. Specifically, in the case of low priority, a prompting strategy, such as voice or SMS prompts, may be implemented, and this application does not impose any specific restrictions. In the case of medium priority, a load reduction strategy may be implemented, along with voice or SMS prompts. In the case of high priority, a shutdown strategy may be implemented, along with voice or SMS prompts.

[0080] The working principle of the turbine low-pressure blade control method proposed in this application will be introduced below with reference to a specific embodiment.

[0081] in, Figure 5 This is a flowchart illustrating the working principle of a control method for low-pressure turbine blades according to an embodiment of this application.

[0082] Step S501: Optical signal acquisition instrument.

[0083] In this embodiment of the application, an optical signal acquisition instrument can be used to receive the Raman scattered light signal transmitted back from the optical fiber.

[0084] Step S502: Photoelectric signal conversion.

[0085] In this embodiment, an optical signal can be converted into an electrical pulse sequence.

[0086] Step S503: Generate exhaust steam temperature field.

[0087] In this embodiment, temperature detection software can be used to calculate temperature based on the Raman scattering principle, and the exhaust temperature field can be generated by combining spatial positioning.

[0088] Step S504: Exhaust steam temperature field analysis.

[0089] In this embodiment, a three-dimensional temperature field reconstruction can be performed to extract the temperature difference and / or temperature gradient in the exhaust steam temperature field.

[0090] Step S505: Perform low-pressure blade monitoring and control.

[0091] In this embodiment, the low-pressure blades can be determined to be abnormal by temperature difference and / or temperature gradient, and corresponding control actions can be generated when an abnormality occurs, thereby eliminating the abnormality.

[0092] The control method for low-pressure turbine blades proposed in this application can extract the temperature difference and / or temperature gradient in the exhaust temperature field obtained by optical fiber and guide vanes, and determine whether the temperature difference is greater than a first temperature threshold and whether the temperature gradient is greater than a second temperature threshold. If the temperature difference is greater than the first temperature threshold, an anomaly is determined in the low-pressure turbine blade, and a first control action is generated to eliminate the anomaly. If the temperature gradient is greater than the second temperature threshold, an anomaly is determined in the low-pressure turbine blade, and a second control action is generated to eliminate the anomaly. This method can capture transient temperature fluctuations in the blade in real time, achieving full-domain circumferential and axial temperature field monitoring of the blade surface and surrounding flow field, accurately locating local overheated areas of the blade, ensuring measurement stability and reliability, extending maintenance cycles, and providing direct, accurate, and long-lasting temperature monitoring assurance for the safe operation of low-pressure blades. This solves the problems in related technologies, such as the low safety and low measurement accuracy of invasive temperature measurement technology; the easy aging and breakage of compensation wires in vibration / high-temperature environments, increasing maintenance costs; and the multiple challenges faced by infrared technology in turbine operation monitoring, including environmental, technical, cost, and operational challenges.

[0093] Next, the control device for low-pressure turbine blades according to an embodiment of this application is described with reference to the accompanying drawings.

[0094] Figure 6 This is a block diagram of a control device for low-pressure turbine blades provided according to an embodiment of this application.

[0095] like Figure 6 As shown, the control device 10 for the low-pressure blades of the steam turbine includes: an extraction module 100, a judgment module 200, a first generation module 300, and a second generation module 400.

[0096] The extraction module 100 is used to acquire the exhaust temperature field of the low-pressure cylinder of the steam turbine using optical fiber and guide vanes, and to extract the temperature difference and / or temperature gradient in the exhaust temperature field.

[0097] The judgment module 200 is used to determine whether the temperature difference is greater than the first temperature threshold and whether the temperature gradient is greater than the second temperature threshold.

[0098] The first generation module 300 is used to determine that there is an abnormality in the low-pressure blade of the steam turbine when the temperature difference is greater than the first temperature threshold, and to generate a first control action for the low-pressure blade of the steam turbine based on the difference between the temperature difference and the first temperature threshold, so as to eliminate the abnormality according to the first control action.

[0099] The second generation module 400 is used to determine that there is an abnormality in the low-pressure blade of the steam turbine when the temperature gradient is greater than the second temperature threshold, and to generate a second control action for the low-pressure blade of the steam turbine based on the difference between the temperature gradient and the second temperature threshold, so as to eliminate the abnormality according to the second control action.

[0100] Optionally, in one embodiment of this application, the extraction module 100 includes: a conversion unit, a calculation unit, and a generation unit.

[0101] The conversion unit is used to convert the optical signal obtained from the optical fiber into the corresponding electrical signal.

[0102] The computing unit is used to calculate the temperature data at at least one measuring point in the optical fiber based on the principle of Raman scattering and electrical signals.

[0103] The generation unit is used to generate the exhaust steam temperature field based on the temperature data.

[0104] It should be noted that the explanation of the control method embodiment for the low-pressure blades of the steam turbine described above also applies to the control device for the low-pressure blades of the steam turbine in this embodiment, and will not be repeated here.

[0105] The control device for low-pressure turbine blades proposed in this application can extract the temperature difference and / or temperature gradient in the exhaust temperature field obtained by optical fiber and guide vanes, and determine whether the temperature difference is greater than a first temperature threshold and whether the temperature gradient is greater than a second temperature threshold. If the temperature difference is greater than the first temperature threshold, an anomaly is determined in the low-pressure turbine blade, and a first control action is generated to eliminate the anomaly. If the temperature gradient is greater than the second temperature threshold, an anomaly is determined in the low-pressure turbine blade, and a second control action is generated to eliminate the anomaly. This device can capture transient temperature fluctuations in the blade in real time, achieving full-domain circumferential and axial temperature field monitoring of the blade surface and surrounding flow field. It can accurately locate local overheated areas of the blade, ensuring measurement stability and reliability, extending the maintenance cycle, and providing direct, accurate, and long-lasting temperature monitoring assurance for the safe operation of low-pressure blades. This solves the problems in related technologies, such as the low safety and low measurement accuracy of invasive temperature measurement technology; the easy aging and breakage of compensation wires in vibration / high-temperature environments, increasing maintenance costs; and the multiple challenges faced by infrared technology in turbine operation monitoring, including environmental, technical, cost, and operational challenges.

[0106] Figure 7 This is a schematic diagram of the structure of an electronic device provided according to an embodiment of this application. The electronic device may include:

[0107] The memory 701, the processor 702, and the computer program stored on the memory 701 and executable on the processor 702.

[0108] When the processor 702 executes the program, it implements the control method for the low-pressure turbine blades provided in the above embodiments.

[0109] Furthermore, electronic devices also include:

[0110] Communication interface 703 is used for communication between memory 701 and processor 702.

[0111] The memory 701 is used to store computer programs that can run on the processor 702.

[0112] The memory 701 may include high-speed RAM memory, and may also include non-volatile memory, such as at least one disk storage device.

[0113] If the memory 701, processor 702, and communication interface 703 are implemented independently, then the communication interface 703, memory 701, and processor 702 can be interconnected via a bus to complete communication between them. The bus can be an Industry Standard Architecture (ISA) bus, a Peripheral Component Interconnect (PCI) bus, or an Extended Industry Standard Architecture (EISA) bus, etc. Buses can be categorized as address buses, data buses, control buses, etc. For ease of representation, Figure 7 The bus is represented by a single thick line, but this does not mean that there is only one bus or one type of bus.

[0114] Optionally, in a specific implementation, if the memory 701, processor 702, and communication interface 703 are integrated on a single chip, then the memory 701, processor 702, and communication interface 703 can communicate with each other through an internal interface.

[0115] The processor 702 may be a central processing unit (CPU), an application specific integrated circuit (ASIC), or one or more integrated circuits configured to implement the embodiments of this application.

[0116] This application also provides a computer-readable storage medium storing a computer program thereon, which, when executed by a processor, implements the above-described control method for low-pressure turbine blades.

[0117] This application also provides a computer program product, including a computer program that, when executed, implements the above-described method for controlling the low-pressure blades of a steam turbine.

[0118] In the description of this specification, the references to terms such as "one embodiment," "some embodiments," "example," "specific example," or "some examples," etc., indicate that a specific feature, structure, material, or characteristic described in connection with that embodiment or example is included in at least one embodiment or example of this application. In this specification, the illustrative expressions of the above terms do not necessarily refer to the same embodiment or example. Furthermore, the specific features, structures, materials, or characteristics described may be combined in any suitable manner in one or more embodiments or examples. Moreover, without contradiction, those skilled in the art can combine and integrate the different embodiments or examples described in this specification, as well as the features of different embodiments or examples.

[0119] Furthermore, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of technical features indicated. Thus, a feature defined as "first" or "second" may explicitly or implicitly include at least one of that feature. In the description of this application, "N" means at least two, such as two, three, etc., unless otherwise explicitly specified.

[0120] Any process or method described in the flowchart or otherwise herein can be understood as representing a module, segment, or portion of code comprising one or N executable instructions for implementing custom logic functions or processes, and the scope of the preferred embodiments of this application includes additional implementations in which functions may be performed not in the order shown or discussed, including substantially simultaneously or in reverse order depending on the functions involved, as should be understood by those skilled in the art to which embodiments of this application pertain.

[0121] The logic and / or steps represented in the flowchart or otherwise described herein, for example, can be considered as a sequenced list of executable instructions for implementing logical functions, and can be embodied in any computer-readable medium for use by, or in conjunction with, an instruction execution system, apparatus, or device (such as a computer-based system, a processor-included system, or other system that can fetch and execute instructions from, an instruction execution system, apparatus, or device). For the purposes of this specification, "computer-readable medium" can be any means that can contain, store, communicate, propagate, or transmit programs for use by, or in conjunction with, an instruction execution system, apparatus, or device. More specific examples (a non-exhaustive list) of computer-readable media include: an electrical connection having one or more wires (electronic device), a portable computer disk drive (magnetic device), random access memory (RAM), read-only memory (ROM), erasable and editable read-only memory (EPROM or flash memory), fiber optic devices, and portable optical disc read-only memory (CDROM). Alternatively, the computer-readable medium may be paper or other suitable media on which the program can be printed, since the program can be obtained electronically by optically scanning the paper or other medium, followed by editing, interpreting, or otherwise processing as necessary, and then stored in a computer memory.

[0122] It should be understood that the various parts of this application can be implemented using hardware, software, firmware, or a combination thereof. In the above embodiments, the N steps or methods can be implemented using software or firmware stored in memory and executed by a suitable instruction execution system. If implemented in hardware, as in another embodiment, it can be implemented using any one or more of the following techniques known in the art: discrete logic circuits having logic gates for implementing logical functions on data signals, application-specific integrated circuits (ASICs) having suitable combinational logic gates, programmable gate arrays (PGAs), field-programmable gate arrays (FPGAs), etc.

[0123] Those skilled in the art will understand that all or part of the steps of the methods described in the above embodiments can be implemented by a program instructing related hardware. The program can be stored in a computer-readable storage medium, and when executed, it includes one or a combination of the steps of the method embodiments.

[0124] Furthermore, the functional units in the various embodiments of this application can be integrated into a processing module, or each unit can exist physically separately, or two or more units can be integrated into a module. The integrated module can be implemented in hardware or as a software functional module. If the integrated module is implemented as a software functional module and sold or used as an independent product, it can also be stored in a computer-readable storage medium.

[0125] The storage medium mentioned above can be a read-only memory, a disk, or an optical disk, etc. Although embodiments of this application have been shown and described above, it is understood that the above embodiments are exemplary and should not be construed as limiting this application. Those skilled in the art can make changes, modifications, substitutions, and variations to the above embodiments within the scope of this application.

Claims

1. A low-pressure cylinder for a steam turbine, comprising an exhaust passage and a first guide ring and a second guide ring disposed within the exhaust passage, characterized in that, Also includes: At least one flow guide vane is disposed between the first flow guide ring and the second flow guide ring, and at least one optical fiber is disposed on the flow guide vane.

2. The low-pressure cylinder of the steam turbine according to claim 1, characterized in that, At least one optical fiber groove is formed on the guide vane, and the optical fiber is disposed in the optical fiber groove; at least a portion of the optical fiber groove extends along the exhaust direction.

3. The low-pressure cylinder of the steam turbine according to claim 2, characterized in that, The fiber optic groove is constructed in a closed loop shape and is arranged circumferentially around the guide vane.

4. The low-pressure cylinder of the steam turbine according to claim 3, characterized in that, The fiber optic slots are configured in multiple ways, and the multiple fiber optic slots are arranged at radial intervals along the guide vanes. The distance between two adjacent fiber optic slots is 9%-15% of the height of the low-pressure cylinder of the steam turbine.

5. A control method for low-pressure blades of a steam turbine, characterized in that, The method employs the low-pressure cylinder of a steam turbine as described in any one of claims 1-4, wherein the method comprises the following steps: The exhaust temperature field of the low-pressure cylinder of the steam turbine is obtained using the optical fiber and the guide vanes, and the temperature difference and / or temperature gradient in the exhaust temperature field are extracted. Determine whether the temperature difference is greater than a first temperature threshold and whether the temperature gradient is greater than a second temperature threshold; If the temperature difference is greater than the first temperature threshold, it is determined that there is an abnormality in the low-pressure blade of the steam turbine, and a first control action of the low-pressure blade of the steam turbine is generated based on the difference between the temperature difference and the first temperature threshold, so as to eliminate the abnormality according to the first control action. If the temperature gradient is greater than the second temperature threshold, it is determined that there is an anomaly in the low-pressure blade of the steam turbine, and a second control action for the low-pressure blade of the steam turbine is generated based on the difference between the temperature gradient and the second temperature threshold, so as to eliminate the anomaly according to the second control action.

6. The control method for low-pressure turbine blades according to claim 5, characterized in that, The method of obtaining the exhaust temperature field of the low-pressure cylinder of the steam turbine using the optical fiber and the guide vanes includes: The optical signal obtained from the optical fiber is converted into a corresponding electrical signal; Based on the Raman scattering principle and the electrical signal, calculate the temperature data at at least one measuring point in the optical fiber; The exhaust temperature field is generated based on the temperature data.

7. A control device for low-pressure blades of a steam turbine, characterized in that, The control method for low-pressure turbine blades as described in any one of claims 5-6, wherein the device comprises: An extraction module is used to obtain the exhaust temperature field of the low-pressure cylinder of the steam turbine using the optical fiber and the guide vanes, and to extract the temperature difference and / or temperature gradient in the exhaust temperature field. The judgment module is used to determine whether the temperature difference is greater than a first temperature threshold and whether the temperature gradient is greater than a second temperature threshold. The first generation module is used to determine that there is an abnormality in the low-pressure blade of the steam turbine when the temperature difference is greater than the first temperature threshold, and to generate a first control action for the low-pressure blade of the steam turbine based on the difference between the temperature difference and the first temperature threshold, so as to eliminate the abnormality according to the first control action. The second generation module is used to determine that there is an abnormality in the low-pressure blade of the steam turbine when the temperature gradient is greater than the second temperature threshold, and to generate a second control action for the low-pressure blade of the steam turbine based on the difference between the temperature gradient and the second temperature threshold, so as to eliminate the abnormality according to the second control action.

8. An electronic device, characterized in that, include: A memory, a processor, and a computer program stored in the memory and executable on the processor, the processor executing the program to implement the control method for low-pressure turbine blades as described in any one of claims 5-6.

9. A computer-readable storage medium having a computer program stored thereon, characterized in that, The program is executed by the processor to implement the control method for the low-pressure blades of a steam turbine as described in any one of claims 5-6.

10. A computer program product, characterized in that, Includes a computer program, which, when executed, is used to implement the control method for low-pressure turbine blades as described in any one of claims 5-6.

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