A method for automatically diagnosing temperature anomaly of internal chamber of steam turbine

Abstract

The application discloses a kind of steam turbine internal chamber temperature anomaly automatic diagnosis method, including the process of reference temperature setting, operating temperature monitoring and temperature anomaly early warning;Reference temperature setting is used as to target chamber set chamber upper half reference temperature and chamber lower half reference temperature;Operating temperature monitoring is used as the real-time wall temperature of chamber upper half and the real-time wall temperature of chamber lower half of target chamber are compared with corresponding reference temperature respectively, if the absolute value of corresponding comparison difference is greater than set threshold, then trigger temperature anomaly early warning process;Temperature anomaly early warning is used as the real-time average temperature of corresponding half of target chamber in each monitoring time period, compared with corresponding reference temperature respectively, if the absolute value of comparison difference of at least two groups of monitoring time periods is greater than set threshold, then output temperature anomaly alarm signal of the corresponding half.The judgment result output by the application can accurately, reliably and objectively reflect whether the temperature of the internal chamber of the steam turbine is abnormal, and reliable dynamic monitoring is realized.

Description

Technical Field

[0001] This invention relates to safety monitoring technology for steam turbine operation, specifically an automatic diagnostic method for abnormal temperature in the internal chambers of a steam turbine. Background Technology

[0002] During the operation of a steam turbine, its operating status needs to be monitored to ensure its safe operation. This includes monitoring the wall temperature of internal chambers such as the steam inlet chamber, steam outlet chamber, and jacket chamber to promptly detect any malfunctions that may affect operational safety and efficiency, such as steam leakage or steam seal failure.

[0003] Currently, there is no objective and standardized diagnostic technique for monitoring temperature anomalies in the internal chambers of steam turbines. Instead, monitoring personnel obtain real-time temperatures of the target chambers from the turbine's DCS system and make subjective judgments based on this data. This judgment is limited to the real-time temperature of the target chamber at that moment and cannot provide an objective and accurate trend analysis. The accuracy of the judgment depends heavily on the professional skills and experience of the monitoring personnel, resulting in significant uncertainty, low objectivity and accuracy, and a high risk of missed or incorrect diagnoses.

[0004] The applicant has searched publicly available domestic patent literature and relevant professional journals and found no technology that is the same as or similar to this application. Summary of the Invention

[0005] The technical objective of this invention is to provide an automatic diagnostic method that can accurately and reliably determine whether the internal chamber temperature of a steam turbine is abnormal, taking into account the special characteristics of monitoring during steam turbine operation and the shortcomings of existing technologies.

[0006] The technical objective of this invention is achieved through the following technical solution: an automatic diagnosis method for abnormal internal temperature of a steam turbine, wherein the automatic diagnosis method includes a reference temperature setting process, an operating temperature monitoring process, and a temperature abnormality early warning process.

[0007] The reference temperature setting process includes:

[0008] When the steam turbine starts up and triggers automatic diagnosis, the upper half reference temperature and lower half reference temperature of the target chamber are manually set within a set cycle.

[0009] Once the manually set reference temperature cycle has been completed, the upper half reference temperature and lower half reference temperature of the target chamber are updated sequentially according to the historical average temperature within the set traceability cycle.

[0010] The operating temperature monitoring process includes:

[0011] Obtain the upper half-real-time wall temperature and lower half-real-time wall temperature of the target chamber from the DCS system.

[0012] Compare the real-time wall temperature of the upper half of the target chamber with the reference temperature of the upper half of the chamber, and calculate the difference.

[0013] Compare the real-time wall temperature of the lower half of the target chamber with the reference temperature of the lower half of the chamber, and calculate the difference.

[0014] If the absolute value of the corresponding comparison difference is greater than the set threshold, the temperature anomaly warning process will be triggered.

[0015] The temperature anomaly early warning process includes:

[0016] Set at least three monitoring time periods according to continuous time;

[0017] Obtain the real-time average temperature of the corresponding half of the target chamber during each monitoring time period;

[0018] The real-time average temperature of the corresponding half of the target chamber during each monitoring time period is compared with the corresponding reference temperature, and the difference is calculated. If the absolute value of the difference between at least two monitoring time periods is greater than the set threshold, an alarm signal indicating that the temperature of the corresponding half is abnormal is output.

[0019] The process of triggering automatic diagnostics is as follows:

[0020] Obtain the current operating load of the steam turbine from the DCS system;

[0021] If the current operating load exceeds the set threshold of the rated power, automatic diagnostics will be activated.

[0022] Furthermore, the threshold for triggering automatic diagnostics is set at 20% of the rated power.

[0023] The reference temperature for the artificially set target chamber is:

[0024] The standard is based on the historical average temperature data of the target chamber of the steam turbine before this start-up; or, the standard is based on the target chamber temperature data allowed by the design when the new steam turbine is put into operation.

[0025] The operating cycle for manually setting the reference temperature of the target chamber is 80 to 100 days.

[0026] The rolling update uses the operating cycle of the manually set reference temperature as the traceability cycle, and updates the historical average temperature within the traceability cycle once a day as the upper half reference temperature or lower half reference temperature of the target chamber.

[0027] The reference temperature is determined as follows:

[0028] The design inlet steam temperature of the cylinder containing the target chamber is evenly divided into multiple inlet steam temperature levels, ranging from the minimum allowable value to the maximum allowable value, in a grading range of 10 to 20°C.

[0029] Obtain the real-time steam inlet temperature of the cylinder containing the target chamber from the DCS system;

[0030] The real-time inlet steam temperature is distributed to the corresponding inlet steam temperature cascade of the group.

[0031] The average value of the steam inlet temperature gradient is obtained within the reference temperature operating cycle, and this average value is used as the reference temperature of the corresponding half of the target chamber at that steam inlet temperature gradient.

[0032] The minimum set threshold during the temperature monitoring process is 10°C.

[0033] The minimum set threshold in the temperature anomaly warning process is 10°C.

[0034] The monitoring time period during the temperature anomaly warning process is set sequentially as three or four monitoring time periods of equal duration.

[0035] The duration of each monitoring period is 15 to 25 minutes;

[0036] During the temperature anomaly warning process, the real-time temperature of the corresponding half of the target chamber is collected once per minute.

[0037] The target chamber includes, but is not limited to, the steam inlet chamber, the steam outlet chamber, or the interlayer chamber inside the steam turbine.

[0038] The beneficial technical effects of this invention are as follows: The above-mentioned technical measures, in view of the special characteristics of monitoring during the operation of steam turbines, form an objective and standardized automatic diagnostic method for threshold alarms and trend change alarms. This automatic diagnostic method basically does not rely on personal subjective experience judgment, at least not during continuous operation after startup. The output judgment results can accurately and reliably reflect whether the internal chamber temperature of the steam turbine is abnormal. It achieves reliable dynamic monitoring of the temperature changes of the internal chamber of the steam turbine, without the monitoring risks of missed judgments and false judgments, which is conducive to improving the safety of steam turbine operation and ensuring power efficiency. Attached Figure Description

[0039] Figure 1 This is a logical relationship flowchart of the present invention. Detailed Implementation

[0040] This invention relates to safety monitoring technology for steam turbine operation, specifically an automatic method for diagnosing temperature anomalies in the internal chambers of a steam turbine. The following description refers to the accompanying drawings. Figure 1The technical solution of this invention will be clearly and thoroughly explained.

[0041] It should be noted that the accompanying drawings of this invention are schematic, and unnecessary details have been simplified to clarify the technical objectives of this invention, so as to avoid obscuring the technical solutions contributed by this invention to the prior art. Furthermore, the terms "approximately" or "basically" used below to refer to quantities or fit relationships mean that reasonable assembly and processing errors are allowed in the industry, and do not literally describe absolute quantities or fit relationships.

[0042] This invention relates to an automatic diagnosis method for abnormal temperature in the internal chambers of a steam turbine. Its triggering mechanism during turbine operation is as follows:

[0043] When the steam turbine starts up, the current operating load of the steam turbine is obtained from the DCS system;

[0044] If the current operating load exceeds the set threshold of the rated power, which is usually 20% of the rated power, this automatic diagnostic method will be triggered.

[0045] The internal chambers of the steam turbine targeted by this invention include, but are not limited to, the steam inlet chamber, the steam outlet chamber, or the sandwich chamber inside the steam turbine.

[0046] This automatic diagnostic method includes a reference temperature setting process, an operating temperature monitoring process, and a temperature anomaly early warning process.

[0047] Specifically, the reference temperature setting process includes two operating conditions. The first operating condition is when the steam turbine starts up. At this time, because the steam turbine has just started and has not yet formed historical temperature data for this operation, it is impossible to directly establish a reference temperature for temperature change trends. The second operating condition is after the steam turbine has completed startup and has been running normally for a period of time. At this time, because the steam turbine has been running continuously, it has formed historical temperature data for this operation, which can be used to establish a reference temperature for temperature change trends.

[0048] More specifically, the process of setting the reference temperature during turbine startup is as follows:

[0049] Using the historical average temperature data of the target chamber before this start-up of the steam turbine as the standard, the upper half reference temperature and lower half reference temperature of the target chamber are manually set within a set period of -80 to 100 days (usually 90 days).

[0050] If the current unit is a new unit that has not been put into operation before, the target chamber temperature data allowed by the design when the new turbine was put into operation should be used as the standard, and the upper half reference temperature and lower half reference temperature of the target chamber should be manually set within a set period of -80 to 100 days (usually 90 days).

[0051] This shows that manually setting the reference temperature relies more on experience and accumulated knowledge. Of course, the reference temperature can be set according to the following temperature gradient grouping: the reference temperature of the upper half / lower half of the chamber is not a constant single value, but rather multiple reference values ​​that vary with different inlet steam temperatures.

[0052] The process of setting the reference temperature after the steam turbine has completed startup and has been running normally for a period of time is as follows:

[0053] The reference temperature operating cycle, set manually, is used as the traceability cycle. The reference temperature is determined by summarizing according to the following rules:

[0054] The design inlet steam temperature of the cylinder containing the target chamber is obtained from the DCS system. The design inlet steam temperature is evenly divided into multiple inlet steam temperature levels in a graded range of approximately 15°C from the minimum allowable value to the maximum allowable value. The temperature value of the aforementioned graded range can be reasonably selected within the range of 10 to 20°C according to the power of the specific unit. For example, a unit with lower power can choose 10°C, a unit with higher power can choose 20°C, and usually 15°C can cover units of various power levels.

[0055] The real-time steam inlet temperature of the cylinder containing the target chamber is obtained from the DCS system. The real-time steam inlet temperature can be collected once per 1 minute (or once per 10 minutes, or once per 30 minutes; the higher the collection frequency, the more accurate the result).

[0056] Within a set reference temperature operating cycle—for example, 90 days—the real-time inlet steam temperature is distributed to the corresponding group of inlet steam temperature levels.

[0057] The average value of the steam inlet temperature gradient is obtained by averaging over the reference temperature operating cycle. This average value is used as the reference temperature of the corresponding half of the target chamber - that is, the upper half and lower half of the chamber at the steam inlet temperature gradient.

[0058] In this way, the reference temperatures of the target chamber corresponding half-body—that is, the upper half and lower half of the chamber—are obtained under each group of steam inlet temperature gradients;

[0059] Based on the baseline temperatures obtained within the aforementioned tracing period, the upper and lower half baseline temperatures of the target chamber will be updated daily after the current baseline temperature cycle has been completed. In other words, after the manually set baseline temperature cycle of -90 days has been completed, the baseline temperature on day 91 will be the historical average temperature of the previous 90 days, the baseline temperature on day 92 will be the historical average temperature of the previous 90 consecutive days backwards, and so on.

[0060] The operating temperature monitoring process includes:

[0061] Obtain the upper and lower real-time wall temperatures of the target chamber at the current inlet steam temperature gradient from the DCS system.

[0062] Compare the real-time upper half wall temperature of the target chamber at the current inlet steam temperature gradient with the reference temperature of the upper half of the chamber at the corresponding inlet steam temperature gradient, and calculate the difference.

[0063] Compare the real-time wall temperature of the lower half of the target chamber at the current inlet steam temperature gradient with the reference temperature of the lower half of the chamber at the corresponding inlet steam temperature gradient, and calculate the difference.

[0064] If the absolute value of the difference between the corresponding upper and lower halves is greater than the set threshold - minimum 10℃, usually 20℃, then the temperature anomaly warning process is triggered.

[0065] The temperature anomaly warning process includes:

[0066] Set at least three, usually four, monitoring time periods of equal duration in a continuous sequence. The duration of each monitoring time period ranges from 15 to 25 minutes, usually 20 minutes.

[0067] With a sampling frequency of once / 1min, the real-time average temperature of the corresponding half of the target chamber (i.e., the upper half / lower half) is obtained in each monitoring time period under the current steam inlet temperature gradient.

[0068] This allows for the acquisition of three or four sets of real-time average temperatures.

[0069] The real-time average temperature of the corresponding half of the target chamber during each monitoring time period is compared with the reference temperature under the corresponding steam inlet temperature gradient, and the difference is calculated.

[0070] If the absolute value of the difference between at least two monitoring time periods is greater than the set threshold - minimum 10℃, usually 20℃, then the temperature of the upper / lower half of the target chamber is determined to be abnormal, and an alarm signal for the corresponding half of the temperature is output.

[0071] The following example uses the temperature monitoring of the intermediate-pressure steam inlet chamber of a certain ultra-supercritical high-pressure combined cylinder unit as the target chamber, combined with... Figure 1 It provides detailed and specific examples illustrating the technical solution of the present invention.

[0072] When monitoring the temperature of the intermediate-pressure steam inlet chamber of this unit using the present invention, it is necessary to extract the data shown in the table below from the DCS system of this unit.

[0073]

[0074]

[0075] See Figure 1 As shown, when the unit starts up, the current operating load D1 of the steam turbine is obtained from the DCS system;

[0076] Determine whether the current operating load D1 of the unit is greater than 20% of the rated power. If D1 ≥ 20% of the rated load, then activate this automatic diagnostic method.

[0077] The design inlet steam temperature of the cylinder containing the target chamber is obtained from the DCS system as 500-605℃. The design inlet steam temperature, from the minimum allowable value of 500℃ to the maximum allowable value of 605℃, is evenly divided into seven groups of inlet steam temperature gradient levels in 15℃ increments:

[0078] (500~515℃) is the first level.

[0079] (515~530℃) is the second level.

[0080] (530~545℃) is the third level.

[0081] (545~560℃) is Level 4.

[0082] (560~575℃) is level five.

[0083] (575~590℃) is level six.

[0084] (590~605℃) is the seventh level.

[0085] During unit startup, the historical average temperature data of the target chamber prior to this startup is used as the standard to manually set the upper and lower reference temperatures of the target chamber for each temperature gradient level over the next 90 days. If the specific temperature gradient levels for each group cannot be obtained, they can only be set based on traditional manual experience.

[0086] Within the aforementioned manually set reference temperature operating cycle, the real-time steam inlet temperature T0 of the cylinder containing the target chamber is obtained from the DCS system. The real-time steam inlet temperature T0 is acquired once per 1 minute.

[0087] Within a 90-day operating cycle of the manually set reference temperature, the real-time steam inlet temperature T0 is delivered and allocated to the corresponding steam inlet temperature tiers of the above-mentioned groups. In other words, the manually set reference temperature operating cycle is used as the traceability cycle for subsequent rolling updates of the reference temperature.

[0088] The average value of the inlet steam temperature gradient for that group of temperature levels over a 90-day operating cycle at the reference temperature is obtained by averaging. This average value is used as the reference temperature for the corresponding half of the target chamber—that is, the upper half and lower half of the chamber—at that inlet steam temperature gradient. In this way, the rolling updated reference temperatures for the corresponding half of the target chamber under each group of inlet steam temperature gradients are obtained—that is, the upper half reference temperature TS′ and the lower half reference temperature TX′.

[0089] After the manually set reference temperature cycle has been running for 90 days, the upper half reference temperature TS′ and lower half reference temperature TX′ of the target chamber will be updated daily according to the corresponding upper half reference temperature TS′ and lower half reference temperature TX′ of the chamber obtained during the above-mentioned traceability cycle.

[0090] Under the aforementioned conditions of manually set or continuously updated reference temperatures, during the dynamic operation of the unit, the real-time upper half wall temperature TS and lower half wall temperature TX of the target chamber at the current inlet steam temperature level are obtained from the DCS system. The real-time upper half wall temperature TS of the target chamber at the current inlet steam temperature level is compared with the corresponding upper half reference temperature TS′ at the same inlet steam temperature level, and the difference ΔTS is calculated. Similarly, the real-time lower half wall temperature TX of the target chamber at the current inlet steam temperature level is compared with the corresponding lower half reference temperature TX′ at the same inlet steam temperature level, and the difference ΔTX is calculated. The specific rules are as follows:

[0091] When the real-time inlet steam temperature T0 is within the first to third inlet steam temperature gradient of the design inlet steam temperature, if the temperature of the upper half of the chamber is |TS-TS′|=△TS>20℃, or the temperature of the lower half of the chamber is |TX-TX′|=△TX>20℃, then the temperature abnormality warning process is triggered.

[0092] When the real-time inlet steam temperature T0 is within the fourth to seventh inlet steam temperature gradient of the design inlet steam temperature, if the temperature of the upper half of the chamber is |TS-TS′|=△TS>15℃, or the temperature of the lower half of the chamber is |TX-TX′|=△TX>15℃, then the temperature abnormality warning process is triggered.

[0093] After the abnormal temperature warning process is triggered, four monitoring time periods are formed in total, with each period lasting 20 minutes, over the next 80 minutes.

[0094] With a sampling frequency of once per minute, the real-time wall temperature of the target chamber corresponding half body that triggers the temperature anomaly warning process is obtained under the current steam inlet temperature gradient and within the current monitoring time period. The real-time average temperature within the monitoring time period is obtained by averaging.

[0095] Thus, the real-time average temperature of the target chamber corresponding half that triggers the temperature anomaly warning process is obtained in each monitoring time period. Specifically, for the upper half of the chamber, the average temperatures of the upper half of the chamber are obtained as follows: TS1 (real-time average temperature in the first monitoring time period), TS2 (real-time average temperature in the second monitoring time period), TS3 (real-time average temperature in the third monitoring time period), and TS4 (real-time average temperature in the fourth monitoring time period); for the lower half of the chamber, the average temperatures of the lower half of the chamber are obtained as follows: TX1 (real-time average temperature in the first monitoring time period), TX2 (real-time average temperature in the second monitoring time period), TX3 (real-time average temperature in the third monitoring time period), and TX4 (real-time average temperature in the fourth monitoring time period).

[0096] The real-time average temperature of the corresponding half of the target chamber during each monitoring time period is compared with the reference temperature under the corresponding steam inlet temperature gradient, and the difference is calculated, such as:

[0097] For the upper half of the chamber, calculate the difference between TS1, TS2, TS3, TS4 and TS′;

[0098] For the lower half of the chamber, calculate the difference between TX1, TX2, TX3, TX4 and TX′.

[0099] If the absolute value of the difference between at least two sets of monitoring time periods in the target chamber corresponding to the half-body that triggers the temperature abnormality warning process is greater than the set threshold of 20℃, then the temperature of the upper half / lower half of the target chamber is determined to be abnormal, and the temperature abnormality alarm signal of the corresponding half-body is output, such as the temperature abnormality of the upper half of the medium-pressure steam inlet chamber or the temperature abnormality of the lower half of the medium-pressure steam inlet chamber.

[0100] The above embodiments are only used to illustrate the present invention and are not intended to limit it.

[0101] Although the present invention has been described in detail with reference to the above embodiments, those skilled in the art should understand that modifications can still be made to the above embodiments, or equivalent substitutions can be made to some of the technical features; and these modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the spirit and scope of the present invention.

Claims

1. A method of automatically diagnosing a temperature anomaly in a chamber of a steam turbine, characterized by, The automatic diagnostic method includes a reference temperature setting process, an operating temperature monitoring process, and a temperature anomaly early warning process. The reference temperature setting process includes: When the steam turbine starts and triggers the automatic start-up diagnostics, the upper half reference temperature and lower half reference temperature of the target chamber are manually set within a set period. Once the manually set reference temperature cycle has been completed, the upper half reference temperature and lower half reference temperature of the target chamber are updated sequentially according to the historical average temperature within the set traceability cycle. The operating temperature monitoring process includes: Obtain the upper half-real-time wall temperature and lower half-real-time wall temperature of the target chamber from the DCS system. Compare the real-time wall temperature of the upper half of the target chamber with the reference temperature of the upper half of the chamber, and calculate the difference. Compare the real-time wall temperature of the lower half of the target chamber with the reference temperature of the lower half of the chamber, and calculate the difference. If the absolute value of the corresponding comparison difference is greater than the set threshold, the temperature anomaly warning process will be triggered. The temperature anomaly early warning process includes: Set at least three monitoring time periods according to continuous time; Obtain the real-time average temperature of the corresponding half of the target chamber during each monitoring time period; The real-time average temperature of the corresponding half of the target chamber during each monitoring time period is compared with the corresponding reference temperature, and the difference is calculated. If the absolute value of the difference between at least two monitoring time periods is greater than the set threshold, an alarm signal for abnormal temperature of the corresponding half is output. The process of triggering automatic diagnostics is as follows: Obtain the current operating load of the steam turbine from the DCS system; If the current operating load exceeds the set threshold of the rated power, automatic diagnostics will be initiated. The rolling update uses the operating cycle of the manually set reference temperature as the traceability cycle, and updates the historical average temperature within the traceability cycle once a day as the upper half reference temperature or lower half reference temperature of the target chamber. The reference temperature is determined as follows: The design inlet steam temperature of the cylinder containing the target chamber is evenly divided into multiple inlet steam temperature levels, ranging from the minimum allowable value to the maximum allowable value, in a grading range of 10 to 20°C. Obtain the real-time steam inlet temperature of the cylinder containing the target chamber from the DCS system; The real-time inlet steam temperature is distributed to the corresponding inlet steam temperature cascade of the group. The average value of the steam inlet temperature gradient is obtained within the reference temperature operating cycle, and this average value is used as the reference temperature of the corresponding half of the target chamber at that steam inlet temperature gradient.

2. The method of claim 1, wherein the temperature of the chamber is measured by a temperature sensor. The threshold for triggering automatic diagnostics is set at 20% of the rated power.

3. The method of claim 1, wherein the step of automatically diagnosing the abnormal temperature of the internal chamber of the steam turbine is characterized by, The reference temperature for the artificially set target chamber is: The standard is based on the historical average temperature data of the target chamber of the steam turbine before this start-up; or, the standard is based on the target chamber temperature data allowed by the design when the new steam turbine is put into operation. The operating cycle for manually setting the reference temperature of the target chamber is 80 to 100 days.

4. The method of claim 1, wherein the step of automatically diagnosing the abnormal temperature of the internal chamber of the steam turbine is characterized by, The minimum set threshold during the temperature monitoring process is 10°C.

5. The method of claim 1, wherein the step of automatically diagnosing the abnormal temperature of the internal chamber of the steam turbine is characterized by, The minimum set threshold in the temperature anomaly warning process is 10°C.

6. The method of claim 1 or 5, wherein The monitoring time period during the temperature anomaly warning process is set sequentially as three or four monitoring time periods of equal duration. The duration of each monitoring period is 15 to 25 minutes; During the temperature anomaly warning process, the real-time temperature of the corresponding half of the target chamber is collected once per minute.

7. The automatic diagnosis method for abnormal temperature in the internal chamber of a steam turbine according to claim 1, characterized in that, The target chamber includes, but is not limited to, the steam inlet chamber, the steam outlet chamber, or the interlayer chamber inside the steam turbine.

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