An isolated automatic control system for supercritical power generation conditions

Abstract

The present application relates to supercritical power generation technical field, disclose a kind of isolated automatic control system for supercritical power generation working condition, comprising: isolated execution module, drive execution module, temperature sensing module and control module, temperature sensing module obtains the wall temperature parameter of valve inner wall and base area, control module calculates the transient transwall temperature gradient of inner and outer wall, and according to the comparison result of the gradient and deformation threshold in closing stroke, control drive execution module stops displacement or retreats to opening direction, waits for the gradient to fall back to safety range, system completes final sealing, the present application is based on thermodynamic evolution law initiative remodeling mechanical displacement, effectively eliminates the extrusion shear force generated by material expansion out of sync, eradicates the fatigue damage and sealing surface sticking and seizure problem of large-diameter valve under deep adjustment peak working condition.

Description

Technical Field

[0001] This invention belongs to the field of supercritical power generation technology, and particularly relates to an isolation automatic control system for supercritical power generation conditions. Background Technology

[0002] Currently, under the operating conditions of supercritical generator units undertaking deep peak shaving and frequent start-stop tasks in the power grid, the isolation electric valve in the main steam pipeline, which is an important component of the supercritical boiler steam power circulation system, is the core of safety assurance and needs to achieve reliable shut-off in a high temperature and high pressure environment above 550℃. Existing technologies usually use thick-walled valve bodies made of heat-resistant alloy steel and are equipped with worm gear reducers with a large transmission ratio. By setting fixed slow opening or uniform closing commands, they attempt to reduce the impact force generated at the moment of switching operating conditions.

[0003] However, due to the highly nonlinear thermodynamic process at the moment of supercritical steam initiation, there is a physical mismatch between the fixed stroke speed control logic and the thermodynamic conduction laws within the valve body metal. During the initial startup phase, high-energy steam at 550°C enters the cold valve body, causing intense convective heat transfer on the inner wall. Meanwhile, the thick-walled valve seat and external pressure-bearing boundary remain at a lower temperature due to the metal's thermal hysteresis constant. This uniform mechanical action, deviating from objective thermodynamic conduction laws, results in a steep transient temperature gradient along the valve body's thickness, generating significant non-uniform thermal expansion and deformation stress within the metal. Simply upgrading the material grade or extending the operating time cannot physically eliminate this mechanical extrusion and shear force caused by heat transfer hysteresis, leading to the failure of critical components during service. Irreversible damage accumulation occurs during the process; in addition to material reinforcement, the control logic and compensation mechanism limit the inherent safety of the equipment. For example, Chinese invention patent application with publication number CN115574110A discloses an isolation valve and a reactor system having it. By setting a bellows or elastic element between the valve seat and the core, the mechanical structure's physical elastic deformation absorbs the high-temperature expansion displacement. However, under supercritical deep peak shaving conditions, the steam parameters have strong transient nonlinear characteristics, and the internal heat conduction of the metal is hysteretic. Passive mechanical compensation is difficult to respond in real time to the evolution of steep temperature gradients inside the metal, and cannot offset the extrusion and shear forces generated by non-uniform thermal stress. This can easily lead to overload of the compensation stroke or response blind zone, and cannot eliminate fatigue damage and sealing surface adhesion caused by heat transfer hysteresis.

[0004] Therefore, how to use the feedback of the valve body metal wall temperature to dynamically adjust the mechanical action stroke and realize the physical coupling between the action path of the actuator and the transient thermodynamic laws in the operation of the supercritical boiler unit has become the technical problem to be solved by this invention. Summary of the Invention

[0005] This invention provides an isolated automatic control system for supercritical power generation conditions, comprising: The isolation execution module is connected to the supercritical main steam pipeline and is used for the physical isolation of the main steam. The drive execution module, connected to the isolated execution module, is used to provide the power for starting and stopping the isolated execution module; The temperature sensing module includes a first acquisition unit and a second acquisition unit; the first acquisition unit is disposed on the inner wall of the isolation execution module and is used to acquire the temperature parameter of the first wall; the second acquisition unit is disposed in the base area of ​​the isolation execution module and is used to acquire the temperature parameter of the second wall. The central control module is connected to the temperature sensing module and the drive execution module. The central control module includes: a data retrieval unit for acquiring the first and second wall temperature parameters; a gradient analysis unit for calculating the numerical difference between the first and second wall temperature parameters to determine the transient cross-wall temperature gradient of the isolation execution module; a joint control unit for comparing the transient cross-wall temperature gradient with the stored thermal deformation threshold in real time during the closing stroke of the isolation execution module; sending a stroke adjustment signal to the drive execution module when the transient cross-wall temperature gradient exceeds the stored thermal deformation threshold, so as to drive the execution module to stop the closing displacement or perform a compensation action of retreating a set distance in the opening direction; and outputting a final clamping signal to the drive execution module after the transient cross-wall temperature gradient falls back to the stored safe gradient range.

[0006] Preferably, the central control module also includes an enthalpy calculation unit, which is used to further refine the stroke adjustment signal through the following logic: acquiring real-time steam pressure data in the supercritical main steam pipeline; determining the transient steam enthalpy at the inlet of the isolation execution module based on the real-time steam pressure data and the first wall temperature parameter; and reducing the mechanical closing rate of the isolation execution module at the end of the closing stroke by means of the stroke adjustment signal when the decrease in transient steam enthalpy within a set time period exceeds the stored enthalpy drop threshold.

[0007] Preferably, the body material of the isolation execution module is WC9 heat-resistant alloy steel, in which the mass percentage of chromium is 2.00% to 2.75% and the mass percentage of molybdenum is 0.90% to 1.20%.

[0008] Preferably, it also includes a hydrophobic protection module, which includes low-level hydrophobic channels disposed at both ends of the isolation execution module and a hydrophobic control unit connected to the low-level hydrophobic channels.

[0009] Preferably, it also includes a displacement feedback module, which is connected to the drive execution module and is used to monitor the real-time displacement of the sealing component in the isolation execution module; the central control module is used to activate the gradient analysis unit when the real-time displacement reaches the stored shutdown warning threshold.

[0010] Preferably, the temperature sensing module has a dual-channel redundant architecture, with the first acquisition unit including a first main sensor and a first backup sensor, and the second acquisition unit including a second main sensor and a second backup sensor.

[0011] Preferably, the drive execution module includes a variable speed power unit and a torque feedback submodule. The torque feedback submodule is used to collect the real-time feedback torque value of the isolation execution module during the shutdown action. The central control module is used to send a power fuse signal to the variable speed power unit when the real-time feedback torque value exceeds the stored torque safety threshold.

[0012] Preferably, the central control module stores a variable threshold table for different generator set load conditions, wherein the stored enthalpy drop threshold is reduced as the generator set load decreases.

[0013] Preferably, it also includes a service assessment module for recording historical extreme values ​​of transient transwall temperature gradients and determining the remaining service life of the isolation execution module based on the historical extreme value data and the stored material fatigue damage model.

[0014] Compared with existing technologies, the isolation automatic control system of this invention for supercritical power generation has the following advantages: 1. In the isolated automatic control of supercritical power generation, the deep coupling of the turbine high torque drive device and the physical feedback logic of the transwall temperature difference enables the active countermeasurement of supercritical transient thermal stress. At the initial stage of unit startup, the system calculates the real-time transwall temperature gradient based on the collected first and second wall temperature parameters, and drives the actuator to perform discrete step throttling actions in the critical stroke range. This process uses a limited flow of steam cut in at a small opening to preheat the thick-walled valve body and base area, so that the heat conduction process inside the metal is physically synchronized with the mechanical action path. This mechanism smooths the transient temperature step between the inner and outer walls of the thick-walled metal from the underlying logic, so that the alternating thermal stress always converges within the physical safety boundary of the material, thereby avoiding fatigue cracking of the base and microscopic damage to the weld caused by lattice expansion dislocation.

[0015] 2. This system utilizes the synergistic effect of a wedge-shaped parallel double-gate structure and a micro-yield logic at the end of the stroke to solve the problem of adhesion and seizing at the isolation boundary under high-temperature conditions. At the end of the rapid shutdown process triggered by unit shutdown, the system monitors the cooling rate of the main steam pipeline and the corresponding metal contraction trend. When it detects that the difference in internal and external cold contraction exceeds the safety tolerance, it drives the turbine actuator to stop the downward pressing action and perform in-situ hovering or micro-upward yielding. After the cold contraction deformation of the base metal stabilizes, the system applies the final self-positioning clamping force. This mechanical compensation mechanism based on the thermodynamic phase change law effectively eliminates the strong shear interference at the interface caused by asynchronous material contraction, ensuring that the large-diameter isolation door always maintains smooth opening and closing and the geometric integrity of the sealing interface during frequent start-stop cycles.

[0016] 3. This system organically combines the heat resistance of WC9 material, the physical protection of low-level drainage pipes, and enthalpy drop stroke interlock control to construct a closed loop for the service stability of the boiler main steam output system under supercritical conditions. The 2.00 to 2.75% chromium and 0.90 to 1.20% molybdenum contained in WC9 material provide the necessary high-temperature creep strength, while the low-level drainage pipes remove accumulated water under cold conditions, eliminating the risk of stress abrupt changes caused by local uneven heating and cooling. With the enthalpy drop gradient control calculated based on real-time pressure and temperature parameters, the system transforms simple mechanical displacement into an active reshaping of the underlying heat transfer curve. This synergistic gain of the multi-dimensional mechanism means that the isolation system is no longer passively subjected to the thermal shock of supercritical steam up to 550℃, but rather the thermal balance process is completed before the mechanical compression process through physical intervention, enhancing the intrinsic safety level of the equipment under deep peak shaving conditions. Attached Figure Description

[0017] Figure 1 This is a diagram showing the module architecture and data interaction topology of the isolation and control system of this invention; Figure 2 This is a flowchart of the adaptive thermal stress control process under the start-up and shutdown conditions of the unit according to the present invention. Detailed Implementation

[0018] The technical solutions of the embodiments of this application will be clearly described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of this application, not all embodiments. All other embodiments obtained by those skilled in the art based on the embodiments of this application are within the scope of protection of this application.

[0019] It should be noted that all directional and positional terms used in this invention, such as: up, down, left, right, front, back, vertical, horizontal, inner, outer, top, bottom, transverse, longitudinal, center, etc., are only used to explain the relative positional relationship and connection between components in a specific state (as shown in the accompanying drawings). They are only for the convenience of describing this invention and do not require that this invention be constructed and operated in a specific orientation. Therefore, they should not be construed as limiting this invention. In addition, the descriptions of "first," "second," etc., in this invention are for descriptive purposes only and should not be construed as indicating or implying their relative importance or implicitly specifying the number of technical features indicated.

[0020] In the description of this invention, unless otherwise explicitly specified and limited, the terms installation, connection, and linking should be interpreted broadly. For example, they can refer to fixed connections, detachable connections, or integral connections; they can refer to mechanical connections; they can refer to direct connections or indirect connections through an intermediate medium; they can refer to the internal connection of two components. For those skilled in the art, the specific meaning of the above terms in this invention can be understood in conjunction with the specific circumstances.

[0021] In the description of this specification, references to the terms "an embodiment," "some embodiments," "illustrative embodiments," "examples," "specific examples," or "some examples," etc., indicate that a specific feature, structure, material, or characteristic described in connection with that embodiment or example is included in at least one embodiment or example of the present invention. In this specification, the illustrative expressions of the above terms do not necessarily refer to the same embodiment or example, and the specific features, structures, materials, or characteristics described may be combined in any suitable manner in one or more embodiments or examples.

[0022] An isolated automatic control system for supercritical power generation conditions includes: The isolation execution module is connected to the supercritical main steam pipeline and is used for the physical isolation of the main steam. The drive execution module, connected to the isolated execution module, is used to provide the power for starting and stopping the isolated execution module; The temperature sensing module includes a first acquisition unit and a second acquisition unit; the first acquisition unit is disposed on the inner wall of the isolation execution module and is used to acquire the temperature parameter of the first wall; the second acquisition unit is disposed in the base area of ​​the isolation execution module and is used to acquire the temperature parameter of the second wall. The central control module is connected to the temperature sensing module and the drive execution module, respectively. The central control module includes: a data retrieval unit for acquiring the first and second wall temperature parameters; a gradient analysis unit for calculating the numerical difference between the first and second wall temperature parameters to determine the transient cross-wall temperature gradient of the isolation execution module; a joint control unit for comparing the transient cross-wall temperature gradient with the stored thermal deformation threshold in real time during the closing stroke of the isolation execution module; sending a stroke adjustment signal to the drive execution module when the transient cross-wall temperature gradient exceeds the stored thermal deformation threshold, so as to drive the execution module to stop the closing displacement or perform a compensation action of retreating a set distance in the opening direction; and outputting a final clamping signal to the drive execution module after the transient cross-wall temperature gradient falls back to the stored safe gradient range.

[0023] Preferably, the central control module also includes an enthalpy calculation unit, which is used to further refine the stroke adjustment signal through the following logic: acquiring real-time steam pressure data in the supercritical main steam pipeline; determining the transient steam enthalpy at the inlet of the isolation execution module based on the real-time steam pressure data and the first wall temperature parameter; and reducing the mechanical closing rate of the isolation execution module at the end of the closing stroke by means of the stroke adjustment signal when the decrease in transient steam enthalpy within a set time period exceeds the stored enthalpy drop threshold.

[0024] Preferably, the body material of the isolation execution module is WC9 heat-resistant alloy steel, in which the mass percentage of chromium is 2.00% to 2.75% and the mass percentage of molybdenum is 0.90% to 1.20%.

[0025] Preferably, it also includes a hydrophobic protection module, which includes low-level hydrophobic channels disposed at both ends of the isolation execution module and a hydrophobic control unit connected to the low-level hydrophobic channels.

[0026] Preferably, it also includes a displacement feedback module, which is connected to the drive execution module and is used to monitor the real-time displacement of the sealing component in the isolation execution module; the central control module is used to activate the gradient analysis unit when the real-time displacement reaches the stored shutdown warning threshold.

[0027] Preferably, the temperature sensing module has a dual-channel redundant architecture, with the first acquisition unit including a first main sensor and a first backup sensor, and the second acquisition unit including a second main sensor and a second backup sensor.

[0028] Preferably, the drive execution module includes a variable speed power unit and a torque feedback submodule. The torque feedback submodule is used to collect the real-time feedback torque value of the isolation execution module during the shutdown action. The central control module is used to send a power fuse signal to the variable speed power unit when the real-time feedback torque value exceeds the stored torque safety threshold.

[0029] Preferably, the central control module stores a variable threshold table for different generator set load conditions, wherein the stored enthalpy drop threshold is reduced as the generator set load decreases.

[0030] Preferably, it also includes a service assessment module for recording historical extreme values ​​of transient transwall temperature gradients and determining the remaining service life of the isolation execution module based on the historical extreme value data and the stored material fatigue damage model.

[0031] Example 1: In a 600MW supercritical thermal power generating unit employing an isolation automatic control system for supercritical power generation conditions, an isolation execution module is connected to the supercritical main steam pipeline for physical isolation of the main steam. The isolation execution module uses a thick-walled valve body made of WC9 heat-resistant alloy steel, with a chromium mass percentage of 2.00% to 2.75% and a molybdenum mass percentage of 0.90% to 1.20% in the thick-walled valve body. When the unit is in the cold start-up phase and the supercritical steam temperature in the main steam pipeline reaches 550℃, a first acquisition unit located on the inner wall of the isolation execution module acquires the first wall temperature parameter. Meanwhile, a second acquisition unit located in the base area acquires the second wall temperature parameter. The central control module receives the above parameters and drives the gradient analysis unit to calculate the difference between the two to determine the transient transwall temperature gradient. ,in, , For transient transwall temperature gradient, For the first wall temperature parameter, This is the second wall temperature parameter.

[0032] Within the initial critical travel interval when the drive execution module activates the isolated execution module, the central control module will calculate the generated data in real time. Compare with the first physical security threshold of storage, and when it is determined When the opening exceeds the first physical safety threshold, the central control module sends a stroke dwell signal to the variable speed power unit in the drive execution module. The drive execution module then interrupts continuous opening displacement at the current 10% opening position and maintains mechanical locking. The confined supercritical steam cut into the gate gap generates heat transfer preheating for the downstream area of ​​the valve body and the base area. The heat is then physically conducted to the outside of the isolation execution module through the metal lattice. and The numerical difference decreases as the heat transfer process continues until the gradient analysis unit detects it. Once the temperature drops below the set second physical safety threshold, the central control module determines that the geometric thermal expansion of the underlying metal has been physically compensated. It then releases the dwell signal and drives the transmission power unit to continue the subsequent start-up stroke.

[0033] During the final stage of the rapid shutdown command triggered by unit shutdown, the displacement feedback module monitors the real-time displacement of the sealing components in the isolation execution module. When the real-time displacement reaches the stored shutdown warning threshold, the central control module activates the gradient analysis unit to monitor the cooling rate of the main steam pipeline and the corresponding metal contraction trend. If the central control module detects that the difference in cold contraction between the inner and outer walls of the isolation execution module exceeds the preset safety tolerance, it drives the execution module to stop its downward pressing action and retracts a set distance in the opening direction, causing the gate to slightly retract upward and hover. After the metal cold contraction deformation in the base area stabilizes, the central control module outputs the final clamping signal to the drive execution module, using self-positioning clamping force to generate a seal. This adjustment method causes the alternating thermal stress to converge to W. Within the physical safety boundary of C9 material, fatigue cracking of the base caused by lattice expansion misalignment is avoided, and the risk of strong shear interference at the interface and adhesion of the sealing surface caused by asynchronous material shrinkage is eliminated. This invention constructs an interlocking control logic based on the supercritical transient thermal flux boundary, so that the mechanical displacement of the isolation execution module and thermodynamic parameters such as steam enthalpy drop form a dynamic closed loop. By physically reshaping the underlying heat conduction curve, the system reduces the peak thermal stress caused by transient temperature difference by relying on dynamic mechanical residence and displacement yielding actions based on physical state settings. It blocks the damage of high-energy steam to the metal lattice structure from the physical evolution path, so that the isolation action is strictly converged within the material's safe physical boundary, ensuring the isolation reliability of the supercritical unit under peak shaving operation conditions.

[0034] Example 2: In a supercritical steam isolation physical test platform simulating a pressure of 25.4 MPa and a rated temperature of 566℃, the isolation actuator module is connected to the main steam pipeline. The isolation actuator module uses a DN300 thick-walled valve body made of heat-resistant alloy steel WC9, with a chromium mass percentage of 2.00% to 2.75% and a molybdenum mass percentage of 0.90% to 1.20%. The test platform is equipped with an armored thermocouple array with a sampling frequency of 100Hz and a temperature measurement accuracy of 0.1℃. The first acquisition unit is located on the inner wall of the valve body of the isolation actuator module, and the second acquisition unit is located in the base area. To simulate an industrial electromagnetic environment, Gaussian white noise with a signal-to-noise ratio of 20dB and power frequency harmonic interference at a frequency of 50Hz are superimposed during data acquisition. The sampling period is... The setting is 10ms. This setting is based on the balance between the accuracy of capturing transient heat flow changes and the data processing load of the computing unit. The test system includes the test group using the technical solution of this invention, the control group using the constant speed start-up method, the control group using WC9 material but with partial missing gradient analysis logic removed, and the out-of-range control group with the first physical safety threshold set at 150℃.

[0035] During the steam cut-in phase of the simulated cold start, the experimental group obtained the first wall temperature parameters. With the second wall temperature parameter The calculated transient transwall temperature gradient During the initial stage of steam induction, the temperature climbed from room temperature to 82.4℃, among which, For the first wall temperature parameter, For the second wall temperature parameter, For transient transwall temperature gradient, when When the first physical safety threshold of the storage is reached, the central control module sends a stroke dwell signal to the drive execution module, locking the opening of the isolation execution module at the 10% preheating position. At this time, the heat on the inner wall of the valve body is physically conducted to the base area. The temperature exhibited a monotonic decay trend and dropped back to 46.8℃. When this value fell below the stored second physical safety threshold, the central control module determined that the geometric thermal expansion of the bottom metal had been compensated and released the dwell signal, driving the transmission power unit to resume operation. Comparative data from each group showed that, under the same interference environment, the control group, lacking a stroke dwell mechanism, experienced a transient thermal stress peak of 312.5 MPa on its inner wall. After 150 simulated cycles, a microcrack with a depth of 0.8 mm was detected at the base root by ultrasonic detection. In contrast, the experimental group, under the adjustment of the gradient analysis unit, limited the stress peak to below 125.6 MPa. After 1200 cycles, no fatigue damage occurred on the sealing surface and base area. Actual measurements of the partially missing control group showed that, due to the lack of heat transfer preheating generated by the stroke dwell mechanism, its... The peak temperature reached 135.2℃, and the generated thermal stress was higher than that of the experimental group, which proves that the alloy material characteristics and the active gradient control logic produce a synergistic gain effect. In the out-of-range control group, when the threshold was set to 150℃, the system caused transient extrusion deformation in the base area due to the failure to trigger the dwell action, and the shut-off displacement deviation reached 1.2mm, accompanied by sealing surface adhesion. When the threshold was set to 15℃, the total opening time was extended from 15.2 minutes to 186.5 minutes. The test results show that the threshold range defined by the present invention achieves consistency between structural safety and response efficiency. This adjustment method based on physical parameter feedback eliminates the interface interference force caused by asynchronous material shrinkage, ensuring the operational stability of the isolation execution module under supercritical power generation conditions.

[0036] Example 3: In the deployment of the isolation automatic control system for supercritical power generation, to determine the first physical safety threshold and the corresponding compensation action step size stored in the central control module, the isolation execution module is connected to the test fixture. Its valve body material is WC9 heat-resistant alloy steel with a chromium mass percentage of 2.00% to 2.75% and a molybdenum mass percentage of 0.90% to 1.20%. Before the test, the effective conductive wall thickness from the inner wall of the valve body to the base area is measured using an ultrasonic thickness gauge. The central control module establishes a physical calibration procedure based on the material fatigue limit, and adjusts it according to the rated operating pressure of the isolated execution module. and effective conductive wall thickness The axial yield stress benchmark of the valve body under thermal equilibrium state was calculated. The linear expansion coefficient of WC9 material at 550℃ was introduced. With elastic modulus Through formula The first physical security threshold is calculated, where, The first physical security threshold, As the axial yield stress reference, The material's Poisson's ratio, For elastic modulus, The coefficient of linear expansion is used. Considering the harshness of supercritical power generation conditions, this invention introduces an engineering safety factor of 0.7 to 0.85 in practical applications to reduce the dimensionality of the theoretical limit value obtained from the above formula. The reduced value is set as the first physical safety threshold to ensure that when the gradient analysis unit triggers the dwell action, the thermal stress level inside the metal is still in the linear elastic region, far below the yield critical point that produces microcracks. Through this pre-set threshold, a physical buffer space is left for the action response of the actuator, preventing stress overload from an engineering practice perspective. This calibration procedure converts the lattice strength of the isolated actuator module into a transient trans-wall temperature gradient limit that can be determined by the gradient analysis unit. The enthalpy calculation unit internally stores a physical property data matrix based on the industry standard thermodynamic properties of water vapor, and the data retrieval unit obtains real-time steam pressure data. With the first wall temperature parameter Then, a two-dimensional spline interpolation algorithm is used to locate the temperature and pressure nodes in the physical property data matrix and output the transient vapor enthalpy values. The central control module internally solidifies WC9 heat-resistant alloy steel, using a comparison table of axial yield stress attenuation and elastic modulus attenuation across various temperature ranges, based on the obtained first wall temperature parameters. The transient yield stress and transient elastic modulus are extracted separately, substituted into the safety threshold calculation formula, and the equivalent trans-wall temperature gradient limit under the current specific wall temperature conditions is calculated and generated. This serves as a dynamic, real-time comparison benchmark for assessing the risk of thermal deformation.

[0037] During the logical operation of the central control module, the enthalpy calculation unit receives transient pressure parameters collected by the main steam pipeline pressure transmitter. Simultaneously retrieve the first wall temperature parameter obtained by the first acquisition unit. The calculation unit inputs the above parameters into the built-in thermodynamic state function to calculate the vapor specific enthalpy at the inlet side of the isolated execution module. Based on the current gate opening output by the displacement feedback module, the transient specific enthalpy on the outlet side is calculated. The central control module is based on the enthalpy drop difference. Correct the stroke adjustment signal of the drive execution module, wherein, The difference in enthalpy drop. The specific enthalpy of the vapor on the inlet side. For the transient specific enthalpy on the outlet side, when the transient enthalpy drop slope exceeds the preset impact energy limit, the system adjusts the output torque frequency of the variable speed power unit to achieve a physical balance between the mechanical energy dissipation generated by the gate displacement and the heat energy input generated by the high-energy steam. This prevents excessive accumulation of thermal stress in local areas of the sealing surface. Here, physical balance means that by adjusting the output pulse frequency of the variable speed power unit, the gate is controlled to move at a micron-level discrete stepping frequency, thereby establishing a dynamic time-scale match between macroscopic mechanical displacement and microscopic heat energy conduction. During the pause interval of the gate's stepping displacement, the limited flow of steam is used to implement thermal shock buffering on local micro-areas of the sealing surface, so that the rate of dissipation of the mechanical work's extrusion energy on the sealing interface is similar in magnitude to the heat flux density absorbed by thermal conduction inside the thick-walled metal. This balance essentially uses the dwell time of mechanical action to exchange for the thermal stress release time of the metal lattice, ensuring that the interface energy level fluctuation is always maintained within the elastic deformation work limit of the WC9 material.

[0038] To ensure the effectiveness of the system's detection under long-term peak-shaving conditions, the central control module executes an initial state definition procedure before each unit startup. The system monitors the static zero-point levels of the first and second acquisition units in an unheated state and compares them with the stored reference signal. If the level deviation exceeds the preset tolerance range, the system automatically calculates a compensation factor. The first wall temperature parameter is superimposed into the subsequent temperature gradient calculation logic. With the second wall temperature parameter After the physical synchronization benchmark is met, the system allows the drive execution module to enter the start command standby state. This closed-loop calibration method based on material constitutive relationship and thermodynamic state feedback eliminates the logic judgment error induced by sensor signal drift, ensures that the displacement of the isolation action is controlled by the thermal fatigue safety curve of the metal material, and enables the supercritical isolation device to maintain structural stability in the environment of frequent thermal cycling.

[0039] Example 4: In the factory calibration scenario of an isolated automatic control system for supercritical power generation, a thermal hysteresis characteristic model of a thick-walled valve body made of WC9 material is established through physical calibration to establish the stroke adjustment benchmark in the joint control unit. The isolated execution module, equipped with the first and second acquisition units, is placed in a simulated heating environment. A constant rate of heat input is applied to the inner wall of the isolated execution module using a heating device, and the first wall temperature parameter is simultaneously acquired when the inner wall temperature is in the 550℃ range. With the second wall temperature parameter The transient response sequence is used to calculate the corresponding effective conductive wall thickness. The thermal response delay coefficient is stored in the central control module as a physical compensation parameter for correcting the displacement step size of the variable speed power unit, thereby eliminating the interference of the heat transfer lag caused by the thick-walled structure of the large-diameter valve body on the gradient determination.

[0040] When the system faces the initial signal path synchronization debugging conditions during field deployment, the central control module eliminates the measurement residuals generated by the sensor transmission link through the zero-point compensation procedure. With the main steam pipeline in a cold state and the ambient temperature constant, the central control module acquires the original output levels of the first and second acquisition units. If the two levels deviate at the same physical temperature point, the system calculates the static offset and writes it into the hardware register of the gradient analysis unit. At this point, the static offset is used to perform in-situ differential correction on subsequently acquired measurements to ensure the transient transwall temperature gradient. The calculation results are anchored to the actual thermal expansion and contraction state of the metal lattice. After the system completes the level alignment logic, the mechanical stroke control quantity of the isolation execution module is linearly aligned with the real-time temperature difference physical gradient. The on-site calibration steps of the isolation automatic control system are implemented. The main steam pipeline is in a cold shutdown state with a constant external ambient temperature to block the input of supercritical steam source. The central control module reads the first initial static level output by the current ambient noise floor of the first acquisition unit and the second initial static level output by the second acquisition unit, respectively. It executes a subtraction instruction to calculate the difference between the two initial static levels, and the internal non-volatile register generates and writes the compensation factor. Compensation factors are extracted during the subsequent start-up and shutdown process of the generator unit under load. As a fixed bias parameter superimposed on the first wall temperature parameter With the second wall temperature parameter The differential operation link compensates for the static hardware residuals in the temperature sensing module's transmission channel.

[0041] Example 5: In the on-site commissioning scenario of an isolated automatic control system for supercritical power generation adapted to a heterogeneous thermal capacity unit, the enthalpy calculation unit drives discretized iterative logic based on thermodynamic state, retrieving initial transient pressure parameters from the main steam pipeline. With the first wall temperature parameter The system then retrieves the initial enthalpy nodes corresponding to the specified pressure and temperature from the stored supercritical steam property reference library and uses first-order difference operations to determine the specific enthalpy of the inlet-side steam. Based on this, the system calculates the velocity fluctuation at the outlet side according to the flow continuity equation and the current throttling area, and introduces the dynamic head loss caused by the velocity fluctuation as a correction operator into the specific enthalpy calculation model, outputting the transient specific enthalpy at the outlet side. The central control module utilizes the difference The drive isolation execution module generates displacement compensation, and by adjusting the output pulse frequency of the variable speed power unit, it reduces the localized cooling stress caused by the sudden drop in steam enthalpy. For transient pressure parameters, For the first wall temperature parameter, The specific enthalpy of the vapor on the inlet side. For the transient specific enthalpy on the export side, For the enthalpy drop difference, in the specific mapping path, the system converts the current displacement feedback value into a percentage of the gate opening and obtains the flow coefficient from the pre-stored flow characteristic curve. The calculation of dynamic head loss adopts a variant of the Darcy-Weisbach formula, multiplying the square term of the velocity fluctuation by the steam density under supercritical conditions, thereby quantifying it as the deviation in the conversion of kinetic energy to thermal energy. This deviation is corrected for the slope of the isenthalpic throttling curve in the form of a scalar factor, and finally the transient specific enthalpy on the outlet side is determined. The specific value; this process ensures that the deviation in enthalpy calculation caused by drastic changes in flow velocity under different load conditions can be compensated in real time through closed-loop.

[0042] When the system faces low-load operation conditions caused by deep peak shaving, the central control module initiates a response based on the thermal response delay coefficient. The system employs a dynamic correction process to offset the time-scale mismatch in heat conduction within thick-walled metals. The system acquires the real-time temperature rise rate of the metal wall surface through a first and second acquisition unit, and modifies the temperature rise rate with the thermal response delay coefficient. The product of these parameters is used as the time offset input to the gradient analysis unit, and the hysteresis compensation algorithm is used to process the first wall temperature parameter. Perform reverse convolution alignment in the time domain to calculate the resulting transient transwall temperature gradient. This reflects the synchronous heating status of the base area of ​​the isolated execution module. If five consecutive sampling cycles are detected... If the deviation rate exceeds the preset tolerance limit, the system determines that the sensor has drifted and initiates zero-point calibration logic, writing a compensation factor calculated in real time to the hardware register. To correct the temperature difference physical curve, where, The thermal response delay coefficient, For the first wall temperature parameter, For transient transwall temperature gradient, As a compensation factor, which is a dimensionless constant, the mechanical stroke control quantity of the isolated execution module is linearly aligned with the real-time temperature difference physical gradient. The gradient analysis unit executes a hysteresis compensation algorithm using a transfer function model that includes a pure time lag constant, according to a set sampling period. The first wall temperature parameter was obtained by continuously recording the data in the first acquisition unit. Construct a discrete-time series input with a phase lead compensation stage for the discrete state equation, and determine the effective transmission wall thickness in the time domain. Generate thermal response delay coefficient The system calculates a time-phase aligned synchronous inner wall temperature reference and then calculates the relationship between this reference and the second wall temperature parameter. The numerical difference is used to output the transient transwall temperature gradient of the current sampling period to the joint debugging control unit.

[0043] The embodiments of this application have been described above with reference to the accompanying drawings. Unless otherwise specified, the embodiments and features in the embodiments of this application can be combined with each other. This application is not limited to the specific embodiments described above. The specific embodiments described above are merely illustrative and not restrictive. Those skilled in the art can make many other forms under the guidance of this application without departing from the spirit of this application and the scope of protection of this invention, and all of these forms are within the protection scope of this application.

Claims

1. An isolated automatic control system for supercritical power generation, characterized in that, include: The isolation execution module is connected to the supercritical main steam pipeline and is used for the physical isolation of the main steam. The drive execution module, connected to the isolated execution module, is used to provide the power for starting and stopping the isolated execution module; The temperature sensing module includes a first acquisition unit and a second acquisition unit; the first acquisition unit is disposed on the inner wall of the isolation execution module and is used to acquire the temperature parameter of the first wall; the second acquisition unit is disposed in the base area of ​​the isolation execution module and is used to acquire the temperature parameter of the second wall. The central control module is connected to the temperature sensing module and the drive execution module respectively. The central control module includes a data retrieval unit, which is used to acquire the first wall temperature parameter and the second wall temperature parameter. The gradient analysis unit is used to calculate the numerical difference between the first wall temperature parameter and the second wall temperature parameter to determine the transient cross-wall temperature gradient of the isolation execution module; the joint debugging control unit is used to compare the transient cross-wall temperature gradient with the stored thermal deformation threshold in real time during the closing stroke of the isolation execution module; when the transient cross-wall temperature gradient exceeds the stored thermal deformation threshold, it sends a stroke adjustment signal to the drive execution module to drive the execution module to stop the closing displacement or perform a compensation action of retreating a set distance in the opening direction; after the transient cross-wall temperature gradient falls back to the stored safe gradient range, it outputs a final clamping signal to the drive execution module.

2. The isolation automatic control system for supercritical power generation as described in claim 1, characterized in that, The central control module also includes an enthalpy calculation unit, which further refines the stroke adjustment signal through the following logic: acquiring real-time steam pressure data in the supercritical main steam pipeline; determining the transient steam enthalpy at the inlet of the isolation execution module based on the real-time steam pressure data and the first wall temperature parameter; and reducing the mechanical shut-off rate of the isolation execution module at the end of the shut-off stroke by using the stroke adjustment signal when the decrease in transient steam enthalpy within a set time period exceeds the stored enthalpy drop threshold.

3. The isolation automatic control system for supercritical power generation as described in claim 1, characterized in that, The body material of the isolation execution module is WC9 heat-resistant alloy steel, in which the mass percentage of chromium is 2.00% to 2.75% and the mass percentage of molybdenum is 0.90% to 1.20%.

4. The isolation automatic control system for supercritical power generation as described in claim 1, characterized in that, It also includes a hydrophobic protection module, which includes low-level hydrophobic channels located at both ends of the isolation execution module, and a hydrophobic control unit connected to the low-level hydrophobic channels.

5. The isolation automatic control system for supercritical power generation as described in claim 1, characterized in that, It also includes a displacement feedback module, which is connected to the drive execution module and is used to monitor the real-time displacement of the sealing components in the isolation execution module; the central control module is used to activate the gradient analysis unit when the real-time displacement reaches the stored shutdown warning threshold.

6. The isolation automatic control system for supercritical power generation conditions according to claim 1, characterized in that, The temperature sensing module has a dual-channel redundant architecture. The first acquisition unit includes a first main sensor and a first backup sensor, and the second acquisition unit includes a second main sensor and a second backup sensor.

7. The isolation automatic control system for supercritical power generation as described in claim 1, characterized in that, The drive execution module includes a transmission power unit and a torque feedback submodule. The torque feedback submodule is used to collect the real-time feedback torque value of the isolation execution module during the shutdown action. The central control module is used to send a power fuse signal to the transmission power unit when the real-time feedback torque value exceeds the stored torque safety threshold.

8. The isolation automatic control system for supercritical power generation conditions according to claim 2, characterized in that, The central control module stores a variable threshold table for different generator load conditions. The stored enthalpy drop threshold is adjusted as the generator load decreases.

9. The isolation automatic control system for supercritical power generation as described in claim 1, characterized in that, It also includes a service assessment module, which records historical extreme data of transient transwall temperature gradients and determines the remaining service life of the isolation execution module based on the historical extreme data and the stored material fatigue damage model.

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