A method for evaluating pressure of a through-flow part of a high-pressure cylinder of a steam turbine

Abstract

The application discloses a kind of steam turbine high-pressure cylinder through-flow part pressure evaluation method, the method is by primary, secondary correction, actual high-pressure cylinder through-flow part pressure is adjusted to same governing valve opening degree and rated main steam pressure and rated main steam temperature, and the high-pressure cylinder through-flow part pressure P tII After correction is obtained;The high-pressure cylinder through-flow part pressure P tII After correction is compared with high-pressure cylinder through-flow part pressure rated value.In operation, when, evaluate high-pressure cylinder through-flow part pressure anomaly.

Description

Technical Field

[0001] This invention relates to a method for assessing the pressure of the flow passage section of a steam turbine high-pressure cylinder, belonging to the field of thermal power generation technology. Background Technology

[0002] The pressure in the high-pressure cylinder flow path is a crucial indicator for monitoring the integrity of a steam turbine during operation. Field testing is currently the primary method for obtaining turbine operating parameters and characteristic information. However, the health status of equipment changes constantly, and performance aging is an objective law. Conventional test results can only represent the equipment and operating status at that specific time, resulting in short-term effectiveness and poor sustainability.

[0003] To facilitate operators' timely understanding of the turbine's condition and scientific assessment of whether the pressure in the high-pressure cylinder's flow path is abnormal, this invention proposes a method for assessing the pressure in the high-pressure cylinder's flow path of a steam turbine. Summary of the Invention

[0004] The purpose of this invention is to facilitate operators' timely understanding of the turbine's condition and to scientifically assess whether the pressure in the high-pressure cylinder's flow passage is abnormal. This invention proposes a method for assessing the pressure in the high-pressure cylinder's flow passage of a steam turbine.

[0005] The technical solution implemented by this invention is as follows: A method for evaluating the pressure of the high-pressure cylinder flow passage in a steam turbine, wherein the method adjusts the actual pressure of the high-pressure cylinder flow passage to the same valve opening and rated main steam pressure and rated main steam temperature through primary and secondary corrections, thereby obtaining the corrected pressure P of the high-pressure cylinder flow passage. tII The pressure P of the high-pressure cylinder flow passage after correction will be adjusted. tII Pressure rating of the flow passage section of the high-pressure cylinder Comparison. During operation, when When this occurs, assess the pressure anomaly in the flow passage.

[0006] The method incorporates the valve opening, main steam pressure P0, main steam temperature T0, and pressure P in the high-pressure cylinder flow section. t and temperature T t Parameters with a dead zone less than 0.1% are recorded, rounded to three decimal places, and added to the DCS historical database. Among these, the pressure P in the high-pressure cylinder flow path... t and temperature T t It includes the regulating stage pressure and temperature, the pressure and temperature after the first stage of the high-pressure cylinder, and the pressure and temperature after the second stage of the high-pressure cylinder.

[0007] The method continuously and synchronously collects data on valve opening, main steam pressure P0, main steam temperature T0, and pressure P in the high-pressure cylinder flow section during operation. t and temperature T t The sampling frequency of the test points was set to 1 time / second.

[0008] The method describes pressure ratios for each stage, including the regulating stage pressure ratio, the first stage pressure ratio of the high-pressure cylinder, and the second stage pressure ratio of the high-pressure cylinder. The pressure ratio for each stage at different valve openings is equal to the pressure of the corresponding high-pressure cylinder flow section divided by the main steam pressure.

[0009]

[0010] Where: ε t P is the stage pressure ratio; t P0 represents the pressure of the high-pressure cylinder flow path; P0 represents the main steam pressure.

[0011] The method calculates the pressure P of the high-pressure cylinder flow section after the first correction under different valve openings according to formula (2). tI :

[0012]

[0013] In the formula: P tI The pressure of the high-pressure cylinder flow path after the first calibration; P′ t This represents the actual pressure of the flow path. P'0 is the rated main steam pressure; P'0 is the actual main steam pressure. T'0 is the rated main steam temperature; T'0 is the actual main steam temperature. To achieve the rated main steam pressure and rated main steam temperature The rated high-pressure cylinder flow section temperature corresponding to the valve opening; T′ t This represents the actual temperature of the flow passage section of the high-pressure cylinder.

[0014] The method uses the pressure ratio of each stage at different valve openings and with rated main steam pressure and rated main steam temperature as the reference value; the reference value of the pressure ratio of each stage The actual measurement can be performed by gradually closing the regulating valve under rated main steam pressure and rated main steam temperature. Under the same regulating valve opening, the percentage deviation of the pressure ratio of each stage is calculated according to formula (3).

[0015]

[0016] In the formula: This represents the percentage deviation of the pressure ratio for each stage. This serves as the reference value for the pressure ratio of each stage; ε t The pressure ratio for each stage.

[0017] The method uses the pressure of the high-pressure cylinder flow passage after the first correction at different valve openings and rated main steam pressures and temperatures as the reference value; the reference value of the pressure of the high-pressure cylinder flow passage after the first correction. The actual measurement can be performed by gradually closing the regulating valve under rated main steam pressure and rated main steam temperature. Under the same regulating valve opening, the percentage deviation θ of the pressure in the high-pressure cylinder flow section after the first correction is calculated according to formula (4). t .

[0018]

[0019] In the formula: θ t This represents the percentage deviation of the pressure in the high-pressure cylinder flow passage after the first calibration. This is the reference value for the pressure in the high-pressure cylinder flow path after the first calibration; P tI This represents the pressure of the high-pressure cylinder flow passage after the first calibration.

[0020] The method, implemented in spreadsheet software, calculates the percentage deviation of pressure ratios at different valve openings for each stage. As the horizontal axis parameter, θ represents the percentage deviation of pressure after the first correction. t Using the ordinate parameter, a two-dimensional scatter plot is generated and linearly fitted to obtain the relationship between the two.

[0021] The method is described in equation (5) to calculate the pressure P of the high-pressure cylinder flow section after the second correction under different valve openings. tII :

[0022]

[0023] In the formula: P tII This is the pressure of the high-pressure cylinder flow passage after the second calibration.

[0024] The method describes the pressure of the high-pressure cylinder flow section under different valve openings, rated main steam pressures, and rated main steam temperatures. As rated values; the actual pressure of the high-pressure cylinder flow passage must be adjusted to the same valve opening and the rated parameters must be below for comparison. When When this occurs, assess the pressure anomaly in the flow passage.

[0025] The beneficial effect of this invention is that operators can understand the turbine status in a timely manner without relying on third-party tests, and scientifically assess whether the pressure of the high-pressure cylinder flow passage is abnormal, providing a basis for unit operation and maintenance. Attached Figure Description

[0026] To more clearly illustrate the technical solutions of the embodiments of the present invention, the drawings used in the following description of the embodiments will be briefly introduced. Obviously, the drawings described below are some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0027] Figure 1 This is a schematic diagram of the flow passage section of the high-pressure cylinder in an embodiment of the present invention. Detailed Implementation

[0028] Specific embodiments of the present invention are shown in the figures. The following will refer to the accompanying drawings in conjunction with the embodiments of the present invention. Figure 1 The technical solutions in the embodiments of the present invention will be clearly and completely described.

[0029] This invention provides a method for assessing the pressure of the flow path in a high-pressure cylinder of a steam turbine, comprising the following steps:

[0030] The method involves primary and secondary corrections to adjust the actual high-pressure cylinder flow passage pressure to the same valve opening and rated main steam pressure and temperature, thereby obtaining the corrected high-pressure cylinder flow passage pressure P. tII The pressure P of the high-pressure cylinder flow passage after correction will be adjusted. tII Pressure rating of the flow passage section of the high-pressure cylinder Comparison. During operation, when When this occurs, assess the pressure anomaly in the flow passage.

[0031] The method incorporates the valve opening, main steam pressure P0, main steam temperature T0, and pressure P in the high-pressure cylinder flow section. t and temperature T t Parameters with a dead zone less than 0.1% are recorded, rounded to three decimal places, and added to the DCS historical database. Among these, the pressure P in the high-pressure cylinder flow path... t and temperature T t It includes the regulating stage pressure and temperature, the pressure and temperature after the first stage of the high-pressure cylinder, and the pressure and temperature after the second stage of the high-pressure cylinder.

[0032] The method continuously and synchronously collects data on valve opening, main steam pressure P0, main steam temperature T0, and pressure P in the high-pressure cylinder flow section during operation. t and temperature T t The sampling frequency of the test points was set to 1 time / second.

[0033] The method describes pressure ratios for each stage, including the regulating stage pressure ratio, the first stage pressure ratio of the high-pressure cylinder, and the second stage pressure ratio of the high-pressure cylinder. The pressure ratio for each stage at different valve openings is equal to the pressure of the corresponding high-pressure cylinder flow section divided by the main steam pressure.

[0034]

[0035] Where: ε t P is the stage pressure ratio; t P0 represents the pressure of the high-pressure cylinder flow path; P0 represents the main steam pressure.

[0036] The method calculates the pressure P of the high-pressure cylinder flow section after the first correction under different valve openings according to formula (2). tI :

[0037]

[0038] In the formula: P tI The pressure of the high-pressure cylinder flow path after the first calibration; P′ t This represents the actual pressure of the flow path. P'0 is the rated main steam pressure; P'0 is the actual main steam pressure. T'0 is the rated main steam temperature; T'0 is the actual main steam temperature. To achieve the rated main steam pressure and rated main steam temperature The rated high-pressure cylinder flow section temperature corresponding to the valve opening; T′ t This represents the actual temperature of the flow passage section of the high-pressure cylinder.

[0039] The method uses the pressure ratio of each stage at different valve openings and with rated main steam pressure and rated main steam temperature as the reference value; the reference value of the pressure ratio of each stage The actual measurement can be performed by gradually closing the regulating valve under rated main steam pressure and rated main steam temperature. Under the same regulating valve opening, the percentage deviation of the pressure ratio of each stage is calculated according to formula (3).

[0040]

[0041] In the formula: This represents the percentage deviation of the pressure ratio for each stage. This serves as the reference value for the pressure ratio of each stage; ε t The pressure ratio for each stage.

[0042] The method uses the pressure of the high-pressure cylinder flow passage after the first correction at different valve openings and rated main steam pressures and temperatures as the reference value; the reference value of the pressure of the high-pressure cylinder flow passage after the first correction. The actual measurement can be performed by gradually closing the regulating valve under rated main steam pressure and rated main steam temperature. Under the same regulating valve opening, the percentage deviation θ of the pressure in the high-pressure cylinder flow section after the first correction is calculated according to formula (4). t .

[0043]

[0044] In the formula: θ t This represents the percentage deviation of the pressure in the high-pressure cylinder flow passage after the first calibration. This is the reference value for the pressure in the high-pressure cylinder flow path after the first calibration; P tI This represents the pressure of the high-pressure cylinder flow passage after the first calibration.

[0045] The method, implemented in spreadsheet software, calculates the percentage deviation of pressure ratios at different valve openings for each stage. As the horizontal axis parameter, θ represents the percentage deviation of pressure after the first correction. t Using the ordinate parameter, a two-dimensional scatter plot is generated and linearly fitted to obtain the relationship between the two.

[0046] The method is described in equation (5) to calculate the pressure P of the high-pressure cylinder flow section after the second correction under different valve openings. tII :

[0047]

[0048] In the formula: P tII This is the pressure of the high-pressure cylinder flow passage after the second calibration.

[0049] The method describes the pressure of the high-pressure cylinder flow section under different valve openings, rated main steam pressures, and rated main steam temperatures. As rated values; the actual pressure of the high-pressure cylinder flow passage must be adjusted to the same valve opening and the rated parameters must be below for comparison. When When this occurs, assess the pressure anomaly in the flow passage.

[0050] The above provides a detailed description of the pressure assessment method for the flow passage of a high-pressure cylinder in a steam turbine provided by this invention. Specific examples in this embodiment illustrate the principle and implementation of the invention. The description of the above embodiments is only for the purpose of helping to understand the method and core idea of ​​this invention. It should be noted that those skilled in the art can make several improvements and modifications to this invention without departing from the principle of this invention, and these improvements and modifications also fall within the protection scope of the claims of this invention.

Claims

1. A method of pressure assessment of a throughflow section of a high-pressure cylinder of a steam turbine, characterized in that The method adjusts the actual high-pressure cylinder through-flow part pressure to the corrected high-pressure cylinder through-flow part pressure by one-time and two-time corrections under the same governing valve opening degree, rated main steam pressure and rated main steam temperature ; comparing the corrected high-pressure cylinder through-flow section pressure with the high-pressure cylinder through-flow section pressure rating abnormal high-pressure cylinder through-flow section pressure is assessed when the high-pressure cylinder through-flow section pressure is greater than the high-pressure cylinder through-flow section pressure rating The method records the gate opening, main steam pressure , main steam temperature , high-pressure cylinder through-flow section pressure , and temperature in a dead zone of less than 0.1%, with three decimal places, and adds them into a DCS history database, wherein the high-pressure cylinder through-flow section pressure and temperature include the regulating stage pressure and temperature, the high-pressure cylinder first-stage group rear pressure and temperature, and the high-pressure cylinder second-stage group rear pressure and temperature. The stage pressure ratios include a regulating stage pressure ratio, a first stage pressure ratio of the high-pressure cylinder, and a second stage pressure ratio of the high-pressure cylinder. The stage pressure ratios at different governing valve opening degrees are equal to corresponding high-pressure cylinder through-flow section pressures divided by the main steam pressure, and the expression is: ， wherein is the stage pressure ratio, is the high pressure cylinder through-flow portion pressure, is the main steam pressure.

2. A method of pressure assessment of the flow path section of a high pressure cylinder of a steam turbine according to claim 1, characterized in that, The throttle opening, main steam pressure , main steam temperature , high pressure cylinder through-flow part pressure and temperature are continuously and synchronously collected during operation, and the sampling frequency of the test points is set to 1 time / s.

3. A method of pressure assessment of the flow path section of a high pressure cylinder of a steam turbine according to claim 1, characterized in that, The first correction of the high-pressure cylinder flow part pressure under different throttle opening degrees is calculated The expression is: ， In the formula, is the high-pressure cylinder through-flow section pressure after the first correction, is the actual through-flow section pressure, is the rated main steam pressure, is the actual main steam pressure, is the rated main steam temperature, is the actual main steam temperature, is the rated high-pressure cylinder through-flow section temperature corresponding to the opening of the control valve under the rated main steam pressure and the rated main steam temperature , and is the actual high-pressure cylinder through-flow section temperature.

4. A method of evaluating pressure in a throughflow section of a high-pressure cylinder of a steam turbine according to claim 1, characterized by, The stage pressure ratio at different throttle opening degrees and rated main steam pressure and rated main steam temperature is taken as a reference value The stage pressure ratio at different throttle opening degrees and rated main steam pressure and rated main steam temperature is taken as a reference value The deviation percentage of the pressure ratio of each stage is calculated under the same throttle opening The expression is: ， wherein is the percent deviation of the stage pressure ratio, is the reference value of the stage pressure ratio, is the stage pressure ratio.

5. A method of pressure assessment of the flow path portion of a high pressure cylinder of a steam turbine according to claim 1, characterized by, The first corrected high-pressure cylinder flow portion pressure under different throttle opening degrees and rated main steam pressure and rated main steam temperature is taken as a reference value The deviation percentage of the first corrected high-pressure cylinder flow portion pressure under the same throttle opening degree can be calculated by gradually closing the throttle under rated main steam pressure and rated main steam temperature , and the expression is: ， In the formula, is the deviation percentage of the high-pressure cylinder flow passage portion pressure after the first correction, is the reference value of the high-pressure cylinder flow passage portion pressure after the first correction, is the high-pressure cylinder flow passage portion pressure after the first correction.

6. A method of pressure assessment of the flow path portion of a high pressure cylinder of a steam turbine according to claim 1, characterized by, The deviation percentage of the stage pressure ratio under different throttle opening degrees As the abscissa parameter, the deviation percentage of the pressure after the first correction As the ordinate parameter, a two-dimensional scatter plot is generated and linear fitting is performed, and the relationship is , and are constants.

7. A method of evaluating pressure in a throughflow section of a high-pressure cylinder of a steam turbine according to claim 1, characterized by, The second correction high-pressure cylinder flow section pressure under different throttle opening degrees is calculated The expression is: wherein: P2 is the high pressure cylinder through flow section pressure after the second correction, P1 is the high pressure cylinder through flow section pressure after the first correction, P2 is the high pressure cylinder through flow section pressure after the second correction, and are constants.

8. A method of evaluating pressure in a throughflow section of a high-pressure cylinder of a steam turbine according to claim 1, characterized by, The high-pressure cylinder flow passage part pressure at different governing valve opening degrees and rated main steam pressure, rated main steam temperature As a rated value; the actual high-pressure cylinder flow passage part pressure must be adjusted to the same governing valve opening degree and rated parameter to be compared; When the high-pressure cylinder passage pressure abnormality is evaluated.

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