A method and system for heating participation of an intermediate pressure control valve in a steam turbine

Abstract

This invention relates to the field of steam turbine technology, and discloses a method and system for regulating the heating parameters of a steam turbine intermediate-pressure regulating valve. The method involves acquiring the operating parameters and external heat load demand parameters of the intermediate-pressure regulating valve heating parameter regulation system; constructing a dynamic coupling model between the intermediate-pressure regulating valve opening and the amount of steam extracted for heating; generating an intermediate-pressure regulating valve opening adjustment strategy based on the dynamic coupling model, including the valve opening target value and the rate of change limit; outputting control commands to the intermediate-pressure regulating valve actuator according to the opening adjustment strategy to adjust the amount of steam extracted for heating; correcting the model coefficients of the dynamic coupling model based on the deviation between the adjusted actual heating parameters and the external heat load demand parameters; and achieving precise adjustment of the amount of steam extracted for heating and coordinated control of multiple regulating valves by constructing a dynamic coupling model between the intermediate-pressure regulating valve opening and the amount of steam extracted for heating, combined with safety margin assessment and adaptive coefficient correction, thereby improving the heating response speed, regulation accuracy, and operational safety of the cogeneration unit.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of steam turbines, in particular to a method and system for heat supply parameter regulation of a medium-pressure regulating valve of a steam turbine. BACKGROUND

[0002] The heat supply parameter regulation of a medium-pressure regulating valve of a steam turbine refers to a technology for controlling the heat supply extraction amount by adjusting the opening degree of the medium-pressure cylinder exhaust valve of a steam turbine to meet the external heat load demand, which is widely used in the heat supply regulation field of cogeneration units.

[0003] The existing heat supply parameter regulation method usually adopts a proportional integral control strategy based on fixed valve management logic, and adjusts the opening degree of the valve according to a preset flow characteristic curve and manually set regulation parameters. However, the fixed model in the prior art is difficult to adapt to real-time changes in the operating conditions of the unit, resulting in a mismatch in dynamic coupling characteristics during the regulation process. In addition, the throttling loss of the single valve control mode affects the economy, the flow characteristic of the sequence valve control mode is nonlinear, and the uneven distribution of flow among multiple valves can cause equipment wear differences. At the same time, the contradiction between the rapid regulation requirement and the mechanical safety constraint of the valve restricts the improvement of the heat supply response speed. SUMMARY

[0004] To solve the above technical problems, the purpose of the present application is to provide a method and system for heat supply parameter regulation of a medium-pressure regulating valve of a steam turbine, which realizes accurate regulation of the heat supply extraction amount and coordinated control of multiple valves by constructing a dynamic coupling model of the opening degree of the medium-pressure regulating valve and the heat supply extraction amount, combining safety margin evaluation and adaptive coefficient correction, and improving the heat supply response speed, regulation accuracy and operating safety of the cogeneration unit.

[0005] To achieve the above purpose, the present application provides a method for heat supply parameter regulation of a medium-pressure regulating valve of a steam turbine, comprising:

[0006] Obtaining operating condition parameters and external heat load demand parameters of a heat supply parameter regulation system of a medium-pressure regulating valve of a steam turbine; Based on the operating condition parameters and the external heat load demand parameters, a dynamic coupling model of the opening degree of the medium-pressure regulating valve and the heat supply extraction amount is constructed, which represents the nonlinear mapping relationship between the throttling characteristics of the medium-pressure regulating valve and the heat network backwater temperature and flow; According to the dynamic coupling model, a regulating strategy for the opening degree of the medium-pressure regulating valve is generated, which includes a target value and a change rate limit value of the opening degree; According to the regulating strategy for the opening degree, a control instruction is output to the actuator of the medium-pressure regulating valve to realize the regulation of the heat supply extraction amount, and the actual heat supply parameters after regulation are collected. According to the deviation between the actual heat supply parameters and the external heat load demand parameters, the model coefficients of the dynamic coupling model are corrected.

[0007] Furthermore, based on the operating condition parameters and the external heat load demand parameters, a dynamic coupling model of the medium-pressure regulating valve opening and the amount of steam extracted for heating is constructed, including: The operating parameters are subjected to time-series smoothing and outlier removal. Analyze the flow characteristic curve and valve management function of the medium-pressure regulating valve to determine the correspondence between the regulating valve opening and the steam flow capacity; Calculate the target steam extraction volume for heating by combining the target flow rate of the heating network circulating water and the target temperature difference between the supply and return water in the external heat load demand parameters; Based on the aforementioned correspondence and the target steam extraction rate for heating, a dynamic coupling model is established between the opening of the medium-pressure regulating valve and the steam extraction rate for heating.

[0008] Furthermore, the flow characteristic curve and valve management function of the medium-pressure regulating valve are analyzed, including: To obtain the differences in flow characteristics of medium-pressure control valves in single-valve control mode and sequential valve control mode; Select the valve control mode based on the current load rate and heat load demand trend of the steam turbine; In the sequential valve control mode, the overlap of the opening degree between each medium-pressure regulating valve is optimized to reduce throttling losses; The valve management function is updated based on the optimal valve control mode and the optimized opening overlap.

[0009] Furthermore, based on the aforementioned dynamic coupling model, a medium-pressure regulating valve opening adjustment strategy is generated, including: Obtain the current mechanical stress level and vibration intensity index of the medium-pressure regulating valve; The safety margin of the regulating valve operation is assessed based on the mechanical stress level and the vibration intensity index. When the safety margin meets the preset safety threshold, the initial opening adjustment amount is calculated according to the dynamic coupling model; Based on the requirements of the heating network load change rate and turbine operation stability, the initial opening adjustment amount is subject to rate and amplitude limits to obtain the target value of the valve opening and the change rate limit.

[0010] Furthermore, based on the mechanical stress level and the vibration intensity index, the safety margin of the regulating valve operation is evaluated, including: Obtain temperature field distribution data of medium-pressure regulating valve body material and calculate thermal stress concentration factor; Monitor the axial displacement fluctuation of the valve stem and the oil pressure fluctuation of the actuator in the medium-pressure regulating valve; The mechanical safety boundary of the regulating valve action is comprehensively evaluated based on the thermal stress concentration factor, the axial displacement fluctuation, and the oil pressure fluctuation. The safety margin is determined based on the ratio of the mechanical safety boundary to the theoretical maximum allowable amplitude of motion under the current operating conditions.

[0011] Further, the initial opening adjustment amount is calculated based on the dynamic coupling model, including: Based on the dynamic coupling model, calculate the basic opening value required to meet the target steam extraction capacity for heating. Obtain the flow distribution balance index among multiple medium-pressure regulating valves; Based on the flow distribution balance index, the basic opening value is corrected for deviation to obtain the independent target opening of each valve; The difference between the independent target opening of each control gate and the current actual opening is used as the initial opening adjustment amount.

[0012] Further, outputting control commands to the medium-pressure regulating valve actuator according to the opening adjustment strategy includes: The control command is decomposed into feedforward control components and feedback control components; The feedforward control component and the feedback control component are superimposed and limited to generate the final execution instruction. The final execution command is distributed to one or more medium-pressure regulating valves according to the preset valve management logic; Monitor the actual opening response of the medium-pressure regulating valve. When the tracking deviation between the actual opening and the target opening exceeds the allowable range, trigger command retransmission or alarm.

[0013] Furthermore, the control command is decomposed into feedforward control components and feedback control components, including: The feedforward control component is generated based on the predicted value of the changing trend of the external heat load demand parameters; Based on the real-time deviation between the actual heating parameters and the target value, the feedback control component is generated using a proportional-integral-derivative algorithm. The weighting coefficients of the feedforward control component and the feedback control component are set, and the weighting coefficients are dynamically adjusted according to the system response speed requirements and stability requirements; The rate and amplitude of the superimposed control quantity are limited to ensure that the final execution command meets the mechanical characteristic constraints of the medium-pressure regulating valve actuator.

[0014] Further, the actual heating parameters after adjustment are collected, and the model coefficients of the dynamic coupling model are corrected based on the deviation between the actual heating parameters and the external heat load demand parameters, including: The actual heating steam extraction rate, heating network supply water temperature, and return water temperature after adjustment are collected and used as the actual heating parameters. Calculate the steady-state deviation and dynamic response delay between the actual heating parameters and the external heat load demand parameters; Based on the steady-state deviation and the dynamic response delay, the degree of model mismatch of the dynamic coupling model is identified; Based on the degree of model mismatch, an adaptive algorithm is used to correct the gain coefficient and time constant of the dynamic coupling model.

[0015] To achieve the above objectives, the present invention also provides a steam turbine intermediate-pressure regulating valve heating parameter control system, comprising: The parameter acquisition module is used to acquire the operating condition parameters and external heat load demand parameters of the steam turbine intermediate pressure regulating valve heating parameter control system; The model building module is used to construct a dynamic coupling model of the opening degree of the medium-pressure regulating valve and the amount of steam extracted for heating based on the operating condition parameters and the external heat load demand parameters. The dynamic coupling model represents the nonlinear mapping relationship between the throttling characteristics of the medium-pressure regulating valve and the return water temperature and flow rate of the heating network. The strategy generation module is used to generate a medium-pressure regulating valve opening adjustment strategy based on the dynamic coupling model. The opening adjustment strategy includes a target value for the regulating valve opening and a limit value for the rate of change. The model correction module is used to output control commands to the medium-pressure regulating valve actuator according to the opening adjustment strategy to realize the adjustment of the heating steam extraction volume, collect the actual heating parameters after adjustment, and correct the model coefficients of the dynamic coupling model according to the deviation between the actual heating parameters and the external heat load demand parameters.

[0016] Compared with the prior art, the beneficial effects of the present invention are as follows: This invention discloses a method and system for regulating the heating parameters of a steam turbine intermediate-pressure regulating valve. The method involves acquiring the operating parameters and external heat load demand parameters of the system; constructing a dynamic coupling model between the intermediate-pressure regulating valve opening and the amount of steam extracted for heating; generating a regulating valve opening adjustment strategy based on the dynamic coupling model, including the valve opening target value and the rate of change limit; outputting control commands to the intermediate-pressure regulating valve actuator according to the opening adjustment strategy to adjust the amount of steam extracted for heating; correcting the model coefficients of the dynamic coupling model based on the deviation between the adjusted actual heating parameters and the external heat load demand parameters; and achieving precise adjustment of the amount of steam extracted for heating and coordinated control of multiple regulating valves by constructing a dynamic coupling model between the intermediate-pressure regulating valve opening and the amount of steam extracted for heating, combined with safety margin assessment and adaptive coefficient correction. This improves the heating response speed, regulation accuracy, and operational safety of the cogeneration unit. Attached Figure Description

[0017] Various other advantages and benefits will become apparent to those skilled in the art upon reading the following detailed description of preferred embodiments. The accompanying drawings are for illustrative purposes only and are not intended to limit the invention. Furthermore, the same reference numerals denote the same parts throughout the drawings. In the drawings: Figure 1 A schematic flowchart of a method for adjusting the heating parameters of a steam turbine intermediate pressure regulating valve is shown in an embodiment of the present invention. Figure 2 A schematic diagram of a steam turbine intermediate pressure regulating valve heating parameter regulation system is shown in an embodiment of the present invention. Detailed Implementation

[0018] The specific embodiments of the present invention will be described in further detail below with reference to the accompanying drawings and examples. The following examples are for illustrative purposes only and are not intended to limit the scope of the invention.

[0019] In the description of this application, it should be understood that the terms "center", "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are only for the convenience of describing this application and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on this application.

[0020] 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. Therefore, a feature defined as "first" or "second" may explicitly or implicitly include one or more of that feature. In the description of this application, unless otherwise stated, "a plurality of" means two or more.

[0021] In the description of this application, it should be noted that, unless otherwise expressly specified and limited, the terms "installation," "connection," and "linking" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; and they can refer to the internal connection between two components. Those skilled in the art can understand the specific meaning of the above terms in this application based on the specific circumstances.

[0022] The following is a description of preferred embodiments of the present invention in conjunction with the accompanying drawings.

[0023] like Figure 1 As shown, an embodiment of the present invention discloses a method for adjusting the heating parameters of a steam turbine intermediate-pressure regulating valve, comprising: S110: Obtain the operating condition parameters and external heat load demand parameters of the steam turbine intermediate pressure regulating valve heating parameter control system; S120: Based on the operating condition parameters and the external heat load demand parameters, a dynamic coupling model of the opening degree of the medium-pressure regulating valve and the amount of steam extracted for heating is constructed. The dynamic coupling model characterizes the nonlinear mapping relationship between the throttling characteristics of the medium-pressure regulating valve and the return water temperature and flow rate of the heating network. S130: Based on the dynamic coupling model, a medium-pressure regulating valve opening adjustment strategy is generated, the opening adjustment strategy including the valve opening target value and the change rate limit; S140: Output control commands to the medium-pressure regulating valve actuator according to the opening adjustment strategy to realize the adjustment of the heating steam extraction volume, collect the actual heating parameters after adjustment, and correct the model coefficients of the dynamic coupling model according to the deviation between the actual heating parameters and the external heat load demand parameters.

[0024] In this embodiment, the operating parameters include the turbine intermediate-pressure cylinder inlet steam pressure, inlet steam temperature, intermediate-pressure exhaust steam pressure, and real-time power generation load. External heat load demand parameters include the requested heat supply from the heating network, the heating network circulating water flow demand, and the target supply water temperature. Pressure and temperature sensors are installed on the intermediate-pressure regulating valve body to acquire the aforementioned operating parameters at a sampling frequency of once per second. External heat load demand parameters are received in real-time through a data communication interface established with the heating network dispatch center.

[0025] In some embodiments of this application, a dynamic coupling model of the opening degree of the medium-pressure regulating valve and the amount of steam extracted for heating is constructed based on the operating condition parameters and the external heat load demand parameters, including: The operating parameters are subjected to time-series smoothing and outlier removal. Analyze the flow characteristic curve and valve management function of the medium-pressure regulating valve to determine the correspondence between the regulating valve opening and the steam flow capacity; Calculate the target steam extraction volume for heating by combining the target flow rate of the heating network circulating water and the target temperature difference between the supply and return water in the external heat load demand parameters; Based on the aforementioned correspondence and the target steam extraction rate for heating, a dynamic coupling model is established between the opening of the medium-pressure regulating valve and the steam extraction rate for heating.

[0026] In this embodiment, the time-series smoothing process uses a moving average algorithm with a window length of 10 seconds to eliminate high-frequency noise interference during sensor acquisition. Outlier removal employs the three-sigma criterion, discarding data points exceeding the mean by ±3 standard deviations and replacing them with linear interpolation of preceding and following normal data. The flow characteristic curves are obtained through valve flow characteristic tests conducted during the turbine commissioning phase, recording the actual flow coefficients of the regulating valves at different opening degrees. The valve management function refers to the logical rules governing how the control system coordinates and allocates the opening degrees of multiple medium-pressure regulating valves, including single-valve control and sequential valve control modes. The calculation of the target heating steam extraction rate is based on the principle of heat network energy balance, i.e., the heat released by the heating steam extraction should be equal to the heat absorbed by the heat network water. Specifically, it is calculated by multiplying the target value of the heat network circulating water flow rate by the target value of the supply and return water temperature difference, and then multiplying it by the specific heat capacity coefficient of water.

[0027] In this embodiment, the medium-pressure regulating valve opening command, the heating network return water temperature, and the heating network circulating water flow rate are used as input variables, and the actual heating steam extraction volume is used as the output variable to construct a dual-channel model framework with feedforward and feedback channels. A static mapping layer is established based on the correspondence, dividing the interval of the medium-pressure regulating valve opening from 0 to 100% into 20 discrete nodes. Each node corresponds to a standard steam extraction volume benchmark value, and linear interpolation is used between adjacent nodes to determine the steam extraction volume corresponding to the intermediate opening. A dynamic inertial element is introduced, setting the steam volume time constant to 8 seconds. This time constant reflects the buffering effect of the steam volume between the medium-pressure cylinder exhaust pipe and the heating steam extraction port on pressure changes. The valve actuator time constant is set to... The 2-second time constant reflects the response delay of the servo hydraulic motor from receiving the command to completing the mechanical action. A heating network condition correction layer is established. Based on the empirical correction coefficient that corresponds to a 5% decrease in steam extraction capacity for every 10-degree Celsius increase in heating network return water temperature, and the flow coupling coefficient that corresponds to an 8% increase in steam extraction demand for every 100 tons per hour increase in heating network circulating water flow, the output of the static mapping layer is corrected in real time. The target heating steam extraction volume is used as the expected output value of the model. By comparing the difference between the expected output and the current model calculation, the recursive least squares algorithm is used to identify and update the node reference values, steam volume time constant, and heating network condition correction coefficient in the static mapping layer online, forming a dynamic coupling model that can adapt to changes in operating conditions.

[0028] The beneficial effects of the above technical solution are: by preprocessing the operating condition parameters, the data quality is improved, ensuring the accuracy of model construction; by analyzing the valve flow characteristics and valve management function, a precise correspondence between opening degree and flow capacity is established, providing reliable basic data support for the generation of subsequent regulation strategies.

[0029] In some embodiments of this application, the flow characteristic curve and valve management function of the medium-pressure regulating valve are analyzed, including: To obtain the differences in flow characteristics of medium-pressure control valves in single-valve control mode and sequential valve control mode; Select the valve control mode based on the current load rate and heat load demand trend of the steam turbine; In the sequential valve control mode, the overlap of the opening degree between each medium-pressure regulating valve is optimized to reduce throttling losses; The valve management function is updated based on the optimal valve control mode and the optimized opening overlap.

[0030] In this embodiment, the flow characteristic difference refers to the difference between the total flow characteristic when all valves operate synchronously in single-valve control mode and the total flow characteristic when valves operate sequentially in sequential valve control mode. Single-valve mode offers good flow characteristic linearity but suffers from large throttling losses, while sequential valve mode offers smaller throttling losses but may have a nonlinear flow characteristic region. The current load factor refers to the ratio of the turbine's real-time power generation load to its rated load. When the load factor is below 70% and the heat load demand is rapidly increasing, single-valve control mode is selected to achieve better regulation linearity; when the load factor is above 70% and the heat load demand is relatively stable, sequential valve control mode is selected to reduce throttling losses. The opening overlap refers to the degree of overlap in sequential valve control mode where the next valve begins to open before the previous valve is fully open. The optimization goal is to control the overlap between 5% and 10%, ensuring a smooth transition of flow characteristics while minimizing throttling losses.

[0031] The beneficial effects of the above technical solution are as follows: by dynamically selecting the valve control mode according to the unit load rate and heat load demand, an optimized balance between regulation performance and economy is achieved; by optimizing the opening overlap, the throttling loss in the sequential valve control mode is reduced, and the thermal economy of the unit is improved; by updating the valve management function, the control system can adapt to different operating conditions, ensuring the flexibility and efficiency of regulation.

[0032] In some embodiments of this application, a medium-pressure regulating valve opening adjustment strategy is generated based on the dynamic coupling model, including: Obtain the current mechanical stress level and vibration intensity index of the medium-pressure regulating valve; The safety margin of the regulating valve operation is assessed based on the mechanical stress level and the vibration intensity index. When the safety margin meets the preset safety threshold, the initial opening adjustment amount is calculated according to the dynamic coupling model; Based on the requirements of the heating network load change rate and turbine operation stability, the initial opening adjustment amount is subject to rate and amplitude limits to obtain the target value of the valve opening and the change rate limit.

[0033] In this embodiment, the mechanical stress level is measured by strain gauge sensors installed on the surface of the control valve body, and the vibration intensity index is obtained by collecting data from an acceleration sensor installed on the control valve actuator and performing spectral analysis. Vibration intensity is typically expressed as the effective value of vibration velocity. The safety margin is a dimensionless coefficient representing the proximity of the current mechanical stress level and vibration intensity to the maximum allowable value of the equipment. The preset safety threshold is set to 1.5, meaning that the control valve operation is considered safe when the safety margin is greater than 1.5. This threshold is determined based on the design specifications provided by the turbine manufacturer and long-term operating experience, ensuring sufficient safety margin to prevent equipment damage during control valve operation. Rate limitation refers to limiting the opening change rate to within 2% per second to prevent excessively rapid valve operation from causing severe pressure fluctuations in the turbine's intermediate-pressure cylinder. Amplitude limitation means that the opening change in a single adjustment does not exceed 10%, avoiding excessive adjustment amplitude from affecting the stable operation of the unit.

[0034] The beneficial effects of the above technical solution are: by monitoring the mechanical stress and vibration state of the regulating valve in real time and assessing the safety margin, the safety of the regulation process is ensured; by limiting the rate and amplitude of the initial opening adjustment, the problem of unstable unit operation caused by excessively fast or large adjustment is avoided, and the coordination and unity of heating regulation and safe unit operation are achieved.

[0035] In some embodiments of this application, the safety margin of the regulating valve operation is evaluated based on the mechanical stress level and the vibration intensity index, including: Obtain temperature field distribution data of medium-pressure regulating valve body material and calculate thermal stress concentration factor; Monitor the axial displacement fluctuation of the valve stem and the oil pressure fluctuation of the actuator in the medium-pressure regulating valve; The mechanical safety boundary of the regulating valve action is comprehensively evaluated based on the thermal stress concentration factor, the axial displacement fluctuation, and the oil pressure fluctuation. The safety margin is determined based on the ratio of the mechanical safety boundary to the theoretical maximum allowable amplitude of motion under the current operating conditions.

[0036] In this embodiment, temperature field distribution data is collected at 12 temperature measuring points arranged on the valve body surface. The internal temperature distribution of the valve body is reconstructed using the finite element method, and then the thermal stress concentration factor caused by temperature non-uniformity is calculated. The thermal stress concentration factor is defined as the ratio of the local maximum thermal stress to the average thermal stress. Axial displacement fluctuation is measured by a linear displacement sensor installed on the valve stem, reflecting the mechanical vibration of the valve stem during the opening and closing process. Oil pressure fluctuation is measured by a pressure sensor installed on the hydraulic oil circuit of the actuator, reflecting the stability of the hydraulic system. The mechanical safety boundary refers to the maximum permissible mechanical stress and vibration level that the control valve can safely operate under the current operating conditions, which is determined by the design limits provided by the equipment manufacturer and the current actual operating conditions.

[0037] The beneficial effects of the above technical solution are: by monitoring the thermal stress, mechanical displacement and hydraulic system status of the regulating gate in multiple dimensions, the mechanical safety boundary of the regulating gate action can be comprehensively assessed, providing a reliable basis for judging the safety of the regulating gate action; by calculating the safety margin, a balance between adjustment demand and equipment safety protection is achieved, preventing the risk of equipment damage caused by over-adjustment.

[0038] In some embodiments of this application, calculating the initial opening adjustment amount based on the dynamic coupling model includes: Based on the dynamic coupling model, calculate the basic opening value required to meet the target steam extraction capacity for heating. Obtain the flow distribution balance index among multiple medium-pressure regulating valves; Based on the flow distribution balance index, the basic opening value is corrected for deviation to obtain the independent target opening of each valve; The difference between the independent target opening of each control gate and the current actual opening is used as the initial opening adjustment amount.

[0039] In this embodiment, the basic opening value refers to the theoretical opening value calculated based on the dynamic coupling model under the assumption that a single valve controls the entire flow. This value reflects the total flow capacity required to meet heating demand. The flow distribution balance index is used to measure the uniformity of flow distribution among multiple medium-pressure valves. It is calculated as the ratio of the standard deviation of the actual flow of each valve to the average flow. The smaller the index, the more balanced the flow distribution. When the flow distribution balance index exceeds 0.15, the flow distribution of each valve is considered uneven, and the basic opening value needs to be corrected. The correction principle is to appropriately reduce the opening of valves with larger flow and correspondingly increase the opening of valves with smaller flow. The correction range is dynamically adjusted according to the degree of imbalance, with a maximum not exceeding 5% of the basic opening value. The independent target opening value refers to the actual target opening value of each valve after flow balance correction. The initial opening adjustment amount is the difference between the independent target opening value and the current actual opening value, representing the amount of opening change that needs to be adjusted.

[0040] The beneficial effects of the above technical solution are as follows: by introducing the flow distribution balance index, the flow of each valve in the multi-valve system is balanced, avoiding uneven equipment wear and reduced efficiency caused by overflow or underflow of some valves; by correcting the deviation of the basic opening value, the total heating demand is met, the balance of operation of each valve is ensured, and the service life of the equipment is extended.

[0041] In some embodiments of this application, outputting control commands to the medium-pressure regulating valve actuator according to the opening adjustment strategy includes: The control command is decomposed into feedforward control components and feedback control components; The feedforward control component and the feedback control component are superimposed and limited to generate the final execution instruction. The final execution command is distributed to one or more medium-pressure regulating valves according to the preset valve management logic; Monitor the actual opening response of the medium-pressure regulating valve. When the tracking deviation between the actual opening and the target opening exceeds the allowable range, trigger command retransmission or alarm.

[0042] In this embodiment, the feedforward control component provides control actions in advance based on the changing trend of external heat load demand parameters to improve the system's response speed; the feedback control component corrects for the deviation between the actual heating parameters and the target value to eliminate steady-state errors. Superposition processing adds the feedforward and feedback components, while limiting processing ensures that the superimposed control command does not exceed the maximum allowable stroke range of the actuator. The valve management logic includes two modes: a single-valve control mode is used when the unit load is below 70% of the rated load, meaning all medium-pressure valves receive the same opening command and operate synchronously; when the unit load is above 70% of the rated load, a sequential valve control mode is used, opening each valve in a preset order to improve throttling efficiency. The allowable range for tracking deviation is set to 2%. That is, when the difference between the actual opening and the target opening exceeds 2% and lasts for more than 5 seconds, the control system determines that the actuator response is abnormal, triggering a command retransmission mechanism to resend the control command. If the deviation is not eliminated after two retransmissions, an alarm signal is issued to prompt the operator to check.

[0043] The beneficial effects of the above technical solution are as follows: the control strategy combining feedforward and feedback control ensures both the rapid response of the system to changes in external load and the accuracy and stability of regulation; the valve management logic realizes coordinated control of multiple control valves and optimizes the valve throttling characteristics; and the opening tracking and monitoring mechanism promptly detects and handles actuator failures, thereby improving the reliability and safety of the system.

[0044] In some embodiments of this application, the control command is decomposed into feedforward control components and feedback control components, including: The feedforward control component is generated based on the predicted value of the changing trend of the external heat load demand parameters; Based on the real-time deviation between the actual heating parameters and the target value, the feedback control component is generated using a proportional-integral-derivative algorithm. The weighting coefficients of the feedforward control component and the feedback control component are set, and the weighting coefficients are dynamically adjusted according to the system response speed requirements and stability requirements; The rate and amplitude of the superimposed control quantity are limited to ensure that the final execution command meets the mechanical characteristic constraints of the medium-pressure regulating valve actuator.

[0045] In this embodiment, the predicted trend value is obtained by averaging the heat load demand of the heating network dispatch center over the next 10 minutes using a sliding window. The feedforward control component is calculated based on this predicted value and the dynamic coupling model, and is used to advance the valve action to compensate for the system's inertial delay. The proportional coefficient of the proportional-integral-derivative (PID) algorithm is set to 0.8, the integral time is set to 60 seconds, and the derivative time is set to 10 seconds. These parameters are determined by adjusting the system's dynamic characteristics. The feedback control component is calculated based on this algorithm and is used to eliminate the deviation between the actual heating parameters and the target value. The dynamic adjustment rule for the weighting coefficients is as follows: when the system response speed requirement is high and the heat load demand changes rapidly, the feedforward weighting coefficient is set to 0.7, and the feedback weighting coefficient is set to 0.3; when the system stability requirement is high and the operating conditions are stable, the feedforward weighting coefficient is set to 0.3, and the feedback weighting coefficient is set to 0.7. The specific values ​​of the rate limit and amplitude limit are determined based on the mechanical characteristics of the actuator to ensure that the control command does not exceed the actuator's response capability and mechanical strength limits.

[0046] The beneficial effects of the above technical solution are: it enables an early response to changes in heat load through feedforward control, eliminates steady-state deviation through feedback control, and the combination of the two improves the control quality of the system; by dynamically adjusting the weight coefficient, the control system can adapt to different operating conditions; and by limiting the rate and amplitude, the actuator is protected, ensuring the safety and reliability of the regulation process.

[0047] In some embodiments of this application, the adjusted actual heating parameters are collected, and the model coefficients of the dynamic coupling model are corrected based on the deviation between the actual heating parameters and the external heat load demand parameters, including: The actual heating steam extraction rate, heating network supply water temperature, and return water temperature after adjustment are collected and used as the actual heating parameters. Calculate the steady-state deviation and dynamic response delay between the actual heating parameters and the external heat load demand parameters; Based on the steady-state deviation and the dynamic response delay, the degree of model mismatch of the dynamic coupling model is identified; Based on the degree of model mismatch, an adaptive algorithm is used to correct the gain coefficient and time constant of the dynamic coupling model.

[0048] In this embodiment, the actual steam extraction rate for heating is measured using a flow orifice plate and a differential pressure transmitter installed on the steam extraction pipeline. The supply and return water temperatures of the heating network are measured using temperature sensors installed on the supply and return water headers of the heating network, respectively. Steady-state deviation refers to the difference between the actual heating parameters and the target values ​​after the system reaches a stable state, such as the difference between the actual supply water temperature and the target supply water temperature. Dynamic response delay refers to the time interval between the issuance of a control command and the start of a significant change in the actual heating parameters, typically measured in seconds. The degree of model mismatch is measured by a comprehensive index that considers both the magnitude of the steady-state deviation and the length of the dynamic response delay. When the steady-state deviation exceeds ±2 degrees Celsius or the dynamic response delay exceeds 30 seconds, the model mismatch is considered high. The adaptive algorithm uses recursive least squares to continuously update the gain coefficient and time constant in the dynamically coupled model based on real-time collected operating data. The gain coefficient reflects the degree of influence of the opening change on the steam extraction rate, and the time constant reflects the inertial characteristics of the system.

[0049] The beneficial effects of the above technical solution are: by collecting the actual heating parameters after adjustment in real time, calculating the steady-state deviation and dynamic response delay, accurately identifying the degree of model mismatch, and using an adaptive algorithm to correct the model coefficients online, the dynamic coupling model can adapt to changes in unit operating conditions and slow drift of equipment characteristics, thus ensuring the accuracy and reliability of the adjustment strategy in long-term operation.

[0050] To further illustrate the technical concept of this invention, the technical solution of this invention will now be described in conjunction with specific application scenarios.

[0051] Correspondingly, such as Figure 2 As shown, this application also provides a steam turbine intermediate-pressure regulating valve heating parameter control system, comprising: The parameter acquisition module is used to acquire the operating condition parameters and external heat load demand parameters of the steam turbine intermediate pressure regulating valve heating parameter control system; The model building module is used to construct a dynamic coupling model of the opening degree of the medium-pressure regulating valve and the amount of steam extracted for heating based on the operating condition parameters and the external heat load demand parameters. The dynamic coupling model represents the nonlinear mapping relationship between the throttling characteristics of the medium-pressure regulating valve and the return water temperature and flow rate of the heating network. The strategy generation module is used to generate a medium-pressure regulating valve opening adjustment strategy based on the dynamic coupling model. The opening adjustment strategy includes a target value for the regulating valve opening and a limit value for the rate of change. The model correction module is used to output control commands to the medium-pressure regulating valve actuator according to the opening adjustment strategy to realize the adjustment of the heating steam extraction volume, collect the actual heating parameters after adjustment, and correct the model coefficients of the dynamic coupling model according to the deviation between the actual heating parameters and the external heat load demand parameters.

[0052] In the description of the above embodiments, specific features, structures, materials, or characteristics may be combined in any suitable manner in one or more embodiments or examples.

[0053] Although the invention has been described above with reference to embodiments, various modifications can be made and components can be replaced with equivalents without departing from the scope of the invention. In particular, as long as there is no structural conflict, the features in the embodiments disclosed in this invention can be combined with each other in any way. The fact that not all of these combinations are described in this specification is merely for the sake of brevity and resource conservation.

[0054] It will be understood by those skilled in the art that the above are merely preferred embodiments of the present invention and are not intended to limit the present invention. Although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art can still modify the technical solutions described in the foregoing embodiments or make equivalent substitutions for some of the technical features. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the protection scope of the present invention.

Claims

1. A method for regulating heating parameters using a steam turbine intermediate-pressure regulating valve, characterized in that, include: Obtain the operating condition parameters and external heat load demand parameters of the steam turbine intermediate pressure regulating valve heating parameter control system; Based on the operating condition parameters and the external heat load demand parameters, a dynamic coupling model of the opening degree of the medium-pressure regulating valve and the amount of steam extracted for heating is constructed. The dynamic coupling model characterizes the nonlinear mapping relationship between the throttling characteristics of the medium-pressure regulating valve and the return water temperature and flow rate of the heating network. Based on the dynamic coupling model, a medium-pressure regulating valve opening adjustment strategy is generated, which includes a target value for the valve opening and a limit value for the rate of change. According to the opening adjustment strategy, control commands are output to the medium-pressure regulating valve actuator to adjust the steam extraction volume for heating. The actual heating parameters after adjustment are collected, and the model coefficients of the dynamic coupling model are corrected based on the deviation between the actual heating parameters and the external heat load demand parameters.

2. The method for adjusting the heating parameters of a steam turbine intermediate pressure regulating valve according to claim 1, characterized in that, Based on the operating condition parameters and the external heat load demand parameters, a dynamic coupling model of the medium-pressure regulating valve opening and the amount of steam extracted for heating is constructed, including: The operating parameters are subjected to time-series smoothing and outlier removal. Analyze the flow characteristic curve and valve management function of the medium-pressure regulating valve to determine the correspondence between the regulating valve opening and the steam flow capacity; Calculate the target steam extraction volume for heating by combining the target flow rate of the heating network circulating water and the target temperature difference between the supply and return water in the external heat load demand parameters; Based on the aforementioned correspondence and the target steam extraction rate for heating, a dynamic coupling model is established between the opening of the medium-pressure regulating valve and the steam extraction rate for heating.

3. The method for adjusting the heating parameters of a steam turbine intermediate pressure regulating valve according to claim 2, characterized in that, Analysis of the flow characteristic curve and valve management function of the medium-pressure regulating valve includes: To obtain the differences in flow characteristics of medium-pressure control valves in single-valve control mode and sequential valve control mode; Select the valve control mode based on the current load rate and heat load demand trend of the steam turbine; In the sequential valve control mode, the overlap of the opening degree between each medium-pressure regulating valve is optimized to reduce throttling losses; The valve management function is updated based on the optimal valve control mode and the optimized opening overlap.

4. The method for adjusting the heating parameters of a steam turbine intermediate pressure regulating valve according to claim 1, characterized in that, Based on the dynamic coupling model, a medium-pressure regulating valve opening adjustment strategy is generated, including: Obtain the current mechanical stress level and vibration intensity index of the medium-pressure regulating valve; The safety margin of the regulating valve operation is assessed based on the mechanical stress level and the vibration intensity index. When the safety margin meets the preset safety threshold, the initial opening adjustment amount is calculated according to the dynamic coupling model; Based on the requirements of the heating network load change rate and turbine operation stability, the initial opening adjustment amount is subject to rate and amplitude limits to obtain the target value of the valve opening and the change rate limit.

5. The method for adjusting the heating parameters of a steam turbine intermediate pressure regulating valve according to claim 4, characterized in that, Based on the mechanical stress level and the vibration intensity index, assess the safety margin of the regulating valve operation, including: Obtain temperature field distribution data of medium-pressure regulating valve body material and calculate thermal stress concentration factor; Monitor the axial displacement fluctuation of the valve stem and the oil pressure fluctuation of the actuator in the medium-pressure regulating valve; The mechanical safety boundary of the regulating valve action is comprehensively evaluated based on the thermal stress concentration factor, the axial displacement fluctuation, and the oil pressure fluctuation. The safety margin is determined based on the ratio of the mechanical safety boundary to the theoretical maximum allowable amplitude of motion under the current operating conditions.

6. The method for adjusting the heating parameters of a steam turbine intermediate pressure regulating valve according to claim 4, characterized in that, The initial opening adjustment amount is calculated based on the dynamic coupling model, including: Based on the dynamic coupling model, calculate the basic opening value required to meet the target steam extraction capacity for heating. Obtain the flow distribution balance index among multiple medium-pressure regulating valves; Based on the flow distribution balance index, the basic opening value is corrected for deviation to obtain the independent target opening of each valve; The difference between the independent target opening of each control gate and the current actual opening is used as the initial opening adjustment amount.

7. The method for adjusting the heating parameters of a steam turbine intermediate pressure regulating valve according to claim 1, characterized in that, According to the opening adjustment strategy, control commands are output to the medium-pressure regulating valve actuator, including: The control command is decomposed into feedforward control components and feedback control components; The feedforward control component and the feedback control component are superimposed and limited to generate the final execution instruction. The final execution command is distributed to one or more medium-pressure regulating valves according to the preset valve management logic; Monitor the actual opening response of the medium-pressure regulating valve. When the tracking deviation between the actual opening and the target opening exceeds the allowable range, trigger command retransmission or alarm.

8. The method for adjusting the heating parameters of a steam turbine intermediate pressure regulating valve according to claim 7, characterized in that, The control command is decomposed into feedforward control components and feedback control components, including: The feedforward control component is generated based on the predicted value of the changing trend of the external heat load demand parameters; Based on the real-time deviation between the actual heating parameters and the target value, the feedback control component is generated using a proportional-integral-derivative algorithm. The weighting coefficients of the feedforward control component and the feedback control component are set, and the weighting coefficients are dynamically adjusted according to the system response speed requirements and stability requirements; The rate and amplitude of the superimposed control quantity are limited to ensure that the final execution command meets the mechanical characteristic constraints of the medium-pressure regulating valve actuator.

9. The method for adjusting the heating parameters of a steam turbine intermediate pressure regulating valve according to claim 1, characterized in that, Collect the adjusted actual heating parameters, and based on the deviation between the actual heating parameters and the external heat load demand parameters, correct the model coefficients of the dynamic coupling model, including: The actual heating steam extraction rate, heating network supply water temperature, and return water temperature after adjustment are collected and used as the actual heating parameters. Calculate the steady-state deviation and dynamic response delay between the actual heating parameters and the external heat load demand parameters; Based on the steady-state deviation and the dynamic response delay, the degree of model mismatch of the dynamic coupling model is identified; Based on the degree of model mismatch, an adaptive algorithm is used to correct the gain coefficient and time constant of the dynamic coupling model.

10. A steam turbine intermediate-pressure regulating valve heating parameter adjustment system, applied to the steam turbine intermediate-pressure regulating valve heating parameter adjustment method as described in any one of claims 1-9, characterized in that, include: The parameter acquisition module is used to acquire the operating condition parameters and external heat load demand parameters of the steam turbine intermediate pressure regulating valve heating parameter control system; The model building module is used to construct a dynamic coupling model of the opening degree of the medium-pressure regulating valve and the amount of steam extracted for heating based on the operating condition parameters and the external heat load demand parameters. The dynamic coupling model represents the nonlinear mapping relationship between the throttling characteristics of the medium-pressure regulating valve and the return water temperature and flow rate of the heating network. The strategy generation module is used to generate a medium-pressure regulating valve opening adjustment strategy based on the dynamic coupling model. The opening adjustment strategy includes a target value for the regulating valve opening and a limit value for the rate of change. The model correction module is used to output control commands to the medium-pressure regulating valve actuator according to the opening adjustment strategy to realize the adjustment of the heating steam extraction volume, collect the actual heating parameters after adjustment, and correct the model coefficients of the dynamic coupling model according to the deviation between the actual heating parameters and the external heat load demand parameters.

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