Water level control method and device of steam generator, terminal equipment and storage medium

Abstract

The invention is suitable for the technical field of computers, and provides a water level control method and device for a steam generator, terminal equipment and a storage medium, and the method comprises the steps that in a low-load working condition mode, a first target parameter of the steam generator is obtained, and first water level control over the steam generator is achieved according to the first target parameter; in the high-load working condition mode, a second target parameter of the steam generator is obtained, and second water level control over the steam generator is achieved according to the second target parameter; in the random fault mode, a third target parameter of the steam generator is obtained, and third water level control over the steam generator is achieved according to the third target parameter; wherein the first target parameter, the second target parameter and the third target parameter are all parameters used for evaluating the water level state of the steam generator. According to the embodiment, the water level stability of the steam generator can be effectively improved, and then the operation safety and stability of a nuclear power unit are improved.

Description

Technical Field

[0001] The present application belongs to the field of computer technology, and in particular, relates to a water level control method, device, terminal equipment and storage medium for a steam generator. Background Art

[0002] As a key equipment for nuclear power units to carry out nuclear power operations, steam generators use the heat generated by nuclear reactors to generate steam, thereby driving steam turbine generators to generate electricity.

[0003] However, during the operation of the current steam generator, the water level in the steam generator is easily disturbed due to various factors, thus affecting the safe and stable operation of the nuclear power unit. Therefore, how to improve the water level stability of the steam generator has become an urgent problem to be solved by those skilled in the art. Summary of the invention

[0004] In view of this, embodiments of the present application provide a water level control method, device, terminal equipment, and storage medium for a steam generator to improve the water level stability of the steam generator.

[0005] A first aspect of an embodiment of the present application provides a water level control method for a steam generator, the water level control method comprising:

[0006] In a low-load operating mode, obtaining a first target parameter of the steam generator, and implementing a first water level control of the steam generator according to the first target parameter;

[0007] Under the high load working mode, obtaining a second target parameter of the steam generator, and implementing a second water level control of the steam generator according to the second target parameter;

[0008] In a random fault mode, obtaining a third target parameter of the steam generator, and implementing a third water level control of the steam generator according to the third target parameter;

[0009] The first target parameter, the second target parameter and the third target parameter are all parameters used to evaluate the water level state of the steam generator.

[0010] A second aspect of an embodiment of the present application provides a water level control device for a steam generator, the water level control device comprising:

[0011] a first control module, configured to obtain a first target parameter of the steam generator in a low-load operating mode, and implement a first water level control of the steam generator according to the first target parameter;

[0012] a second control module, configured to obtain a second target parameter of the steam generator under a high load operating mode, and implement a second water level control of the steam generator according to the second target parameter;

[0013] a third control module, configured to obtain a third target parameter of the steam generator in a random fault mode, and implement a third water level control of the steam generator according to the third target parameter;

[0014] The first target parameter, the second target parameter and the third target parameter are all parameters used to evaluate the water level state of the steam generator.

[0015] The third aspect of the embodiments of the present application provides a terminal device, including a memory, a processor, and a computer program stored in the memory and executable on the processor, wherein when the processor executes the computer program, the steps of the water level control method as described in the first aspect of the embodiments of the present application are implemented.

[0016] A fourth aspect of the embodiments of the present application provides a computer-readable storage medium, wherein the computer-readable storage medium stores a computer program, and when the computer program is executed by a processor, the steps of the water level control method as described in the first aspect of the embodiments of the present application are implemented.

[0017] The first aspect of the embodiment of the present application provides a water level control method, which obtains a first target parameter of the steam generator in a low load operating mode, and implements a first water level control of the steam generator according to the first target parameter; obtains a second target parameter of the steam generator in a high load operating mode, and implements a second water level control of the steam generator according to the second target parameter; obtains a third target parameter of the steam generator in a random fault mode, and implements a third water level control of the steam generator according to the third target parameter; wherein the first target parameter, the second target parameter and the third target parameter are all parameters for evaluating the water level state of the steam generator, so that the water level stability of the steam generator can be effectively improved, thereby improving the safety and stability of the operation of the nuclear power unit.

[0018] It can be understood that the beneficial effects of the second to fourth aspects mentioned above can be found in the relevant description of the first aspect mentioned above, and will not be repeated here. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] In order to more clearly illustrate the technical solutions in the embodiments of the present application, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present application. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying any creative work.

[0020] Figure 1 This is the first water level control logic schematic diagram provided by the embodiment of the present application;

[0021] Figure 2 is a schematic diagram of a water level control method for a steam generator provided in an embodiment of the present application;

[0022] Figure 3 This is a second water level control logic schematic diagram provided in an embodiment of the present application;

[0023] Figure 4 This is a schematic diagram of a main water supply valve control provided in an embodiment of the present application;

[0024] Figure 5 This is a third water level control logic schematic diagram provided in an embodiment of the present application;

[0025] Figure 6 is a structural schematic diagram of a water level control device for a steam generator provided in an embodiment of the present application;

[0026] Figure 7 It is a schematic diagram of the structure of the terminal device provided in an embodiment of the present application. DETAILED DESCRIPTION

[0027] In the following description, specific details such as specific system structures, technologies, etc. are provided for the purpose of illustration rather than limitation, so as to provide a thorough understanding of the embodiments of the present application. However, it should be clear to those skilled in the art that the present application may also be implemented in other embodiments without these specific details. In other cases, detailed descriptions of well-known systems, devices, circuits, and methods are omitted to prevent unnecessary details from obstructing the description of the present application.

[0028] It should also be understood that the term “and / or” used in the specification and appended claims refers to any and all possible combinations of one or more of the associated listed items, and includes these combinations.

[0029] In addition, in the description of the present application specification and the appended claims, the terms "first", "second", "third", etc. are only used to distinguish the descriptions and cannot be understood as indicating or implying relative importance.

[0030] References to "one embodiment" or "some embodiments" etc. described in the specification of this application mean that one or more embodiments of the present application include specific features, structures or characteristics described in conjunction with the embodiment. Therefore, the statements "in one embodiment", "in some embodiments", "in some other embodiments", "in some other embodiments", etc. that appear in different places in this specification do not necessarily refer to the same embodiment, but mean "one or more but not all embodiments", unless otherwise specifically emphasized in other ways. The terms "including", "comprising", "having" and their variations all mean "including but not limited to", unless otherwise specifically emphasized in other ways. "Multiple" means "two" or "more than two".

[0031] The steam generator is a vertical, natural circulation device that produces saturated steam. The reactor coolant flows in the heat transfer tubes, transferring heat to the secondary circuit water outside the tubes. The secondary circuit water circulates naturally in the steam generator, and part of the water becomes saturated steam when flowing outside the heat transfer tubes, which is supplied to the main steam turbine, thereby driving the turbine to generate electricity.

[0032] The water level control of the steam generator of a nuclear power unit mainly includes the speed control of the main feedwater pump and the opening control of the main feedwater valve. The main purpose of the speed control of the main feedwater pump is to adjust the pressure difference between the feedwater main pipe and the steam main pipe (referred to as the steam-water pressure difference) while maintaining the pressure drop of the regulating valve constant, so that it changes parabolically with the load change. The actuator is the main feedwater pump; the opening control of the main feedwater valve refers to setting up an independent water level regulating system for each steam generator, and changing the valve opening of the main feedwater valve to change the feedwater flow rate to achieve the purpose of controlling the water level. The actuators are the main feedwater valve (referred to as the main valve) and the bypass feedwater valve (referred to as the bypass valve).

[0033] The water level control logic of the steam generator is as follows Figure 1 As shown. Among them, ΔP SW Indicates the pressure difference between soda and water, Q ST Indicates steam flow rate, P ST Indicates steam pressure, Q FW Indicates water flow rate, L SG Indicates the current water level of the steam generator, P PW Indicates the secondary circuit image load (wide range), T FW Indicates the feed water temperature, P PN Indicates the secondary circuit image load (narrow range), V O1 Indicates the main valve opening signal, V O2Indicates the bypass valve opening signal. The main feedwater valve opening control is achieved by adjusting the feedwater flow entering the steam generator. The normal feedwater circuit of each steam generator is equipped with two parallel pipelines: the main feedwater valve on the main line is used for water level regulation in high-load operating mode, and the bypass valve on the bypass line is used in low-load operating mode and in the start-up and shutdown phases.

[0034] Therefore, in response to the possible disturbances in the water level of the steam generator under different operating modes, an embodiment of the present application provides a water level control method, by obtaining a first target parameter of the steam generator in a low-load operating mode, and implementing a first water level control of the steam generator according to the first target parameter; in a high-load operating mode, obtaining a second target parameter of the steam generator, and implementing a second water level control of the steam generator according to the second target parameter; in a random fault mode, obtaining a third target parameter of the steam generator, and implementing a third water level control of the steam generator according to the third target parameter; wherein the first target parameter, the second target parameter and the third target parameter are all parameters for evaluating the water level state of the steam generator, so that the water level stability of the steam generator can be effectively improved, thereby improving the safety and stability of the operation of the nuclear power unit.

[0035] It should be noted that, in the present application, the secondary circuit power 0-30% FP is defined as a low-load condition, and the secondary circuit power 30%-100% FP is defined as a high-load condition; in the random fault mode, occasional random faults may cause a large disturbance to the water level of the steam generator, and in severe cases may cause transient conditions such as load shedding or machine tripping of the nuclear power unit.

[0036] Embodiment 1

[0037] like Figure 2 As shown, the water level control method of the steam generator provided in the embodiment of the present application includes the following steps S1 to S3:

[0038] Step S1: Under a low-load operating mode, a first target parameter of the steam generator is obtained, and a first water level control of the steam generator is implemented according to the first target parameter.

[0039] In the application, the first target parameter is a parameter used to evaluate the water level status of the steam generator, including but not limited to steam flow, steam pressure, steam temperature, feed water flow, feed water temperature, feed water quality, feed water pressure, current water level height and other parameters.

[0040] In the application, in the low load mode, that is, when the secondary circuit power is 0-30% FP, the first target parameter of the steam generator is obtained, including obtaining the current water level of the steam generator. If the current water level of the steam generator is L SGDeviating from the steam generator water level threshold L SP A certain range, that is, |L SG -L SP |>λ1, λ1 is set according to actual needs, and the steam generator needs to be controlled at the first water level so that the current water level height of the steam generator is L SG and water level threshold L SP The deviation does not exceed λ1 to improve the stability of the water level.

[0041] In one embodiment, step S1 specifically includes:

[0042] In a preset flow range, obtaining the steam flow and feed water flow of the steam generator;

[0043] If the steam-water deviation between the steam flow rate and the feed water flow rate exceeds a first deviation threshold, optimizing the feed water flow rate and / or the steam flow rate so that the steam-water deviation does not exceed the first deviation threshold;

[0044] Obtain the secondary circuit mirror load and primary circuit thermal power deviation;

[0045] If the power deviation between the secondary-circuit mirror load and the primary-circuit thermal power deviation exceeds a second deviation threshold, the secondary-circuit mirror load is optimized so that the power deviation does not exceed the second deviation threshold.

[0046] In the application, the flow range can be set according to actual needs. For example, in the flow range of 0 to 300 t / h, the steam flow Q ST and water flow rate Q FW , if the steam flow rate Q ST and water flow rate Q FW The soda-water deviation between them exceeds the first deviation threshold, i.e., |Q ST -Q FW |>λ2, λ2 represents the first deviation threshold (λ2 is set according to actual needs), then the feed water flow and / or steam flow needs to be optimized so that the steam-water deviation does not exceed the first deviation threshold.

[0047] In the application, considering the measurement of steam flow Q ST and water flow rate Q FW When the differential pressure measurement principle is used, the error at zero point is relatively large. Therefore, the steam flow rate Q can be controlled ST Output signal at zero point and water flow rate Q FW The accuracy range of the output signal at zero point is to ensure the steam flow rate Q ST and water flow rate Q FW consistency, that is:

[0048] λ b -λ3≤Q ST(0) ≤λ b +λ3;

[0049] λ b -λ3≤Q FW(0) ≤λ b +λ3;

[0050] Among them, λ b Indicates steam flow rate Q ST , water flow rate Q FW The standard value output at zero point, λ3 represents the zero point accuracy control range.

[0051] In the application, during the period from the turbine start-up to the grid connection, the secondary circuit mirror load changes greatly and is unstable. The deviation between the calculated secondary circuit mirror load and the actual steam load is large, causing the bypass valve opening to deviate from the design value, which easily causes the water level fluctuation of the steam generator. Therefore, when the power deviation between the secondary circuit mirror load and the primary circuit thermal power deviation exceeds the second deviation threshold, the secondary circuit mirror load PP is reduced. N Thermal power deviation Q e The power deviation between the two circuits can improve the accuracy of the secondary circuit mirror load and effectively reduce the water level fluctuation of the steam generator during the grid connection period. PN The thermal power deviation of the primary circuit is Q e When the power deviation between them exceeds the second deviation threshold λ4, the secondary circuit mirror load P PN Correction is made to ensure that the secondary circuit mirror load P PN Satisfy |P PN -Q e |≤λ4, where λ4 is set according to actual needs.

[0052] In one embodiment, step S1 further includes:

[0053] Acquiring a current main / bypass valve switching threshold and a corresponding bypass regulating valve margin of the steam generator;

[0054] If the bypass regulating valve margin is less than the preset regulating margin, the current main / bypass valve switching threshold is corrected so that the bypass regulating valve margin is not less than the preset regulating margin.

[0055] In applications, during the operation of nuclear power units, the selection of the main / bypass valve switching threshold is crucial to ensure the water level stability of the steam generator. If the bypass valve's water supply capacity is insufficient when the main / bypass valve is switched, it will directly cause water level fluctuations, which can be manifested as: a decrease in feedwater flow at the same valve opening, and the bypass valve is close to full opening with no adjustment margin when the main bypass valve is switched.

[0056] Therefore, in view of the problem of insufficient water supply capacity of the bypass regulating valve in the low-load operating mode or the startup phase of the nuclear power unit, the present application optimizes the main / bypass valve switching threshold so that the bypass valve has good water supply regulation performance at the main / bypass valve switching point, thereby improving the water level stability of the steam generator in the low-load operating mode.

[0057] Specifically, the method includes: obtaining the current main / bypass valve switching threshold value of the steam generator and the corresponding bypass regulating valve margin; if the current main / bypass valve switching threshold value P PNS Under this condition, the bypass regulating valve margin of the steam generator is less than the preset regulating margin λ5 (i.e.: |100-V O2 |<λ5, where λ5 represents the bypass valve of the steam generator at the main / bypass valve switching threshold P PNS The adjustment margin threshold at the time of the main / bypass valve switching threshold P PNS Correction is made to ensure that the bypass regulating valve margin of the steam generator is not less than the preset regulating margin λ5.

[0058] Under low load operating mode, the water level stability of the steam generator can be effectively improved by analyzing and correcting the steam-water deviation of the steam generator, the secondary circuit mirror load, and the accuracy of the main / bypass valve switching threshold.

[0059] Step S2: Under a high load operating mode, a second target parameter of the steam generator is obtained, and a second water level control of the steam generator is implemented according to the second target parameter.

[0060] In the application, the second target parameter is a parameter used to evaluate the water level status of the steam generator, including but not limited to steam flow, steam pressure, steam temperature, feed water flow, feed water temperature, feed water quality, feed water pressure, current water level height and other parameters.

[0061] In the application, under the high load working mode, that is, when the secondary circuit power is 30% to 100% FP, the second target parameter of the steam generator is obtained, including the maximum and minimum water level heights of the steam generator, so as to determine the oscillation amplitude, oscillation frequency and oscillation period of the water level, and realize the second water level control of the steam generator by analyzing the causes of the oscillation and performing corresponding optimization and adjustment to improve the stability of the water level.

[0062] In one embodiment, step S2 includes:

[0063] In high load working mode, set a fixed sampling period;

[0064] Within n fixed sampling periods, obtaining minimum and maximum water level values ​​and corresponding water level deviations of n groups of steam generators;

[0065] According to the relationship between each group of the water level deviations and the third deviation threshold, it is determined whether the water level of the steam generator oscillates or fluctuates.

[0066] In applications, the fixed sampling period T can be adjusted according to the period T of the coupled oscillation. f The fixed sampling period T cannot be set too short, otherwise the maximum and minimum water level values ​​within an oscillation period cannot be collected; the fixed sampling period T cannot be set too long, otherwise the water level oscillation amplitude change of the steam generator cannot be accurately reflected. Therefore, the fixed sampling period T satisfies the formula T = (1.5 ~ 2)T f That's it.

[0067] In the application, after setting the fixed sampling period, the minimum and maximum water levels of the steam generator and the corresponding water level deviations within n fixed sampling periods are obtained, and then based on the relationship between each set of water level deviations and the third deviation threshold, it is determined whether the water level of the steam generator oscillates.

[0068] For example, in the sampling period T1, the minimum water level L of the steam generator is obtained. SG(min) and minimum water level L SG(max) ; If L SG(max 1) -L SG(min 1) >λ6, then m count is increased by 1; where λ6 is the intervention value of the water level fluctuation amplitude of the steam generator;

[0069] Similarly, in the sampling period T i The minimum water level L of the steam generator can be obtained. SG(min i) and the maximum water level L SG(max i ), if L SG(max i) -L SG(min i) >λ6, then the m count increases by 1;

[0070] In the sampling period T n The minimum water level L of the steam generator can be obtained. SG(min n) and the maximum water level L SG(max n) , if L SG(max n) -L SG(min n) >λ6, then the m count increases by 1;

[0071] In n sampling cycles, the final count m is obtained. If This indicates that the water level of the steam generator oscillates and fluctuates, and needs to be adjusted to improve the stability of the water level. λ7 represents the proportional threshold value of the water level fluctuation amplitude of the steam generator exceeding the intervention value.

[0072] In one embodiment, step S2 specifically includes:

[0073] Acquire a first frequency characteristic and a corresponding first phase difference of a main feedwater pump speed control system, and a second frequency characteristic and a corresponding second phase difference of a main feedwater valve opening control system;

[0074] Obtaining a first regulating parameter of the main feedwater pump speed control system and / or a second regulating parameter of the main feedwater valve opening control system according to the first frequency characteristic, the first phase difference, the second frequency characteristic and the second phase difference;

[0075] The first frequency characteristic and / or the second frequency characteristic are optimized by the first adjustment parameter and / or the second adjustment parameter, so that the water level of the steam generator remains in a stable state.

[0076] In applications, the first frequency characteristic, the first phase difference, the second frequency characteristic and the second phase difference can be obtained by experiments or simulations.

[0077] In applications, the frequency characteristic reflects the control system's ability to respond to signals of different frequencies, and the phase difference reflects the phase difference between the two control systems, that is, the relative time delay between the control signals. Since there is mutual influence and poor coupling between the main feedwater pump speed control system and the main feedwater valve opening control system, when the frequency characteristics and phase difference of the two control systems (main feedwater pump speed control system and main feedwater valve opening control system) are similar, the interaction between them may lead to oscillation amplification, resulting in regulation resonance.

[0078] In application, if it is determined according to the aforementioned embodiment that the water level of the steam generator oscillates and fluctuates, in order to reduce the impact caused by the coupling between the main feed water pump speed control system and the main feed water valve opening control system, the first frequency characteristic and the corresponding first phase difference of the main feed water pump speed control system, as well as the second frequency characteristic and the corresponding second phase difference of the main feed water valve opening control system can be obtained, and the first adjustment parameter of the main feed water pump speed control system can be obtained according to the first frequency characteristic, the first phase difference, the second frequency characteristic and the second phase difference, wherein the first adjustment parameter includes a proportional coefficient (used to improve the response speed and stability of the system) and a time integral constant (used to reduce steady-state errors and avoid oscillations caused by over-integration).

[0079] like Figure 3As shown, by optimizing the proportional coefficient K of the feedwater pump control system p1 The two parameters, T2 and time integral constant T2, can reduce the large amplitude oscillation of the actuators and the regulated quantities of the two regulating systems under stable conditions, thereby improving the stability of the water level control of the steam generator.

[0080] In one embodiment, step S2 specifically further includes:

[0081] If the water level of the steam generator oscillates, a response characteristic curve of the actuator is obtained;

[0082] generating a characteristic parameter adjustment strategy of the actuator according to the response characteristic curve;

[0083] The characteristic parameters of the actuator are adjusted according to the characteristic parameter adjustment strategy so that the water level of the steam generator remains in a stable state.

[0084] In the application, in the water level control system of the steam generator, the response speed of the actuator (such as the main water supply valve) is also an important reason for the fluctuation of the water level regulation. There are many factors that affect the response speed of the actuator. For example, the physical structure and mechanical inertia of the actuator may cause the actuator to respond slowly, or there may be a corresponding delay in the transmission process of the signal from the control system to the actuator. Therefore, judging whether there is hysteresis and poor followability in the water level control from the response characteristic curve of the actuator, so as to optimize and adjust the corresponding characteristic parameters of the actuator, is more conducive to maintaining the water level of the steam generator in a stable state.

[0085] Specifically, if it is determined according to the aforementioned embodiment that the water level of the steam generator oscillates and fluctuates, the response characteristic curve of the actuator is obtained, wherein the response characteristic curve includes but is not limited to a small signal response characteristic curve, a large signal response characteristic curve, and a full stroke time response characteristic curve. According to the response characteristic curve of the actuator, a corresponding characteristic parameter adjustment strategy is generated and the characteristic parameters of the actuator are adjusted, wherein the characteristic parameters include proportional gain, speed gain, and minimum loop gain, thereby achieving the response characteristics of the actuator in terms of good small signal followability, low large signal overshoot, and time response characteristics, which is beneficial to improving the stability of the water level control of the steam generator.

[0086] like Figure 4 The main feed water valve control schematic diagram of the steam generator is shown. In order to improve the working stability of the main feed water valve of the steam generator, the characteristic parameters of the main feed water regulating valve can be adjusted based on the response information and the reference index corresponding to the response information through small signal follow-up setting, large signal overshoot setting and full stroke time response characteristic setting to control the working condition of the main feed water valve.

[0087] The embodiments of the present application improve the stability of the steam generator water level control under the high-load operating mode from the perspective of the response characteristics of the actuator, so that the anti-disturbance capability of the steam generator water level control is effectively improved, and the safe and stable operation of the nuclear power unit is effectively guaranteed.

[0088] In the application, the feedwater flow and steam flow are used as feedforward quantities to control the main valve of the steam generator water level. To prevent abnormal regulation caused by signal fluctuations, the steam flow and steam generator water level process quantities are both equipped with filter modules, but the feedwater flow is not equipped with a filter module. During actual operation, the steam flow and steam generator water level process signals are stable, while the feedwater flow process signal fluctuates greatly, and the actual change characteristics of the process quantity are inconsistent with the logical settings.

[0089] Therefore, the influence of feedforward fluctuation on the regulation system can be reduced by adding a filter module to the main water flow. The specific water level control logic is as follows: Figure 5 As shown, the water flow rate Q FW , Steam flow Q ST , evaporator liquid level L SG (current water level of the steam generator) and the secondary circuit load wide range P PW Participate in main valve control, secondary circuit load wide range P PW Generate water level set value, water level set value and current water level value L SG After performing the difference calculation, a water level deviation signal is generated based on the difference, and the water level deviation signal is input to the water level regulator (PID regulator). The output signal of the water level regulator (PID regulator) is input to the flow regulator (PI regulator, ProportionIntegration, proportional integral regulator) after the difference calculation with the steam-water mismatch signal, and the opening of the main valve is controlled. Among them, the steam-water mismatch signal is based on the water flow rate Q FW , Steam flow Q ST The difference between the two circuit loads is determined. PN Participate in bypass valve control, the output signal of the water level regulator (PID regulator) and the narrow range P of the secondary circuit load PN After the adder operation, it is processed by the P regulator (Proportion) and controls the opening of the bypass valve.

[0090] Step S3: Under the random fault mode, a third target parameter of the steam generator is obtained, and a third water level control of the steam generator is implemented according to the third target parameter.

[0091] In the application, the third target parameter is a parameter used to evaluate the water level status of the steam generator, including but not limited to steam flow, steam pressure, steam temperature, feed water flow, feed water temperature, feed water quality, feed water pressure, current water level height and other parameters.

[0092] In application, under random fault mode, the occurrence of faults is accidental, but some faults will have a great impact on the water level regulation of the steam generator. Severe cases may also cause transient situations such as load shedding or machine tripping of nuclear power units. Therefore, the embodiments of the present application can also improve the water level stability of the steam generator through fault identification and processing.

[0093] In one embodiment, step S3 includes:

[0094] In a random fault mode, obtaining at least one of a steam flow rate, a feedwater flow rate, and a heat balance flow rate;

[0095] Based on the constructed cross-validation system, the differential pressure of the steam flow, the feed water flow and the heat balance flow is corrected with high accuracy;

[0096] Determine the water level state of the steam generator using the corrected steam flow, feed water flow and heat balance flow;

[0097] According to the water level state, a third water level control of the steam generator is implemented.

[0098] In application, through in-depth analysis of the probability distribution characteristics of random failures, when constructing a cross-validation system, it includes establishing two-level aging assessment criteria for degradation / failure, formulating assessment standards based on uncertainty propagation rate-failure probability distribution, and forming a cross-validation system including four forms of fusion redundant measurement comparison, test standard verification, working condition demand matching, and historical concurrent reference.

[0099] In the application, at least one of the steam flow, feed water flow and heat balance flow is obtained under a random fault mode, and then based on the constructed cross-validation system, the steam flow, feed water flow and heat balance flow are corrected with high accuracy for the corresponding differential pressure, and the water level state of the steam generator is determined using the corrected steam flow, feed water flow and heat balance flow data, thereby achieving water level control of the steam generator according to the water level state.

[0100] The embodiment of the present application establishes a steam generator water level reliability improvement strategy from the fault diagnosis dimension, realizes the timely monitoring of abnormal flow measurement deviation, and implements differential pressure high-accuracy correction technology for the deviation channel to improve the accuracy of flow measurement. It is beneficial to improve the stability of steam generator water level control under random fault mode.

[0101] In one embodiment, step S3 specifically further includes:

[0102] Setting a first default value of the transmitter and a second default value of the controller;

[0103] The first default value includes the minimum and maximum limits of the transmitter output signal, and the minimum and maximum limits of the transmitter output signal when a fault is detected; the second default value includes the minimum and maximum quality bit thresholds of the controller receiving signal, and the correction and replacement logic taken when the controller detects a received signal fault;

[0104] When a receiving signal failure is detected, the receiving signal is corrected and replaced using the correction replacement logic, and the corrected receiving signal is used for water level control.

[0105] In the application, in the water level control system of the steam generator, faults or signal abnormalities at the front end of the control system may cause disturbances or transients in the process system. For example, the process quantity abnormality is not linked to the quality level signal, the process quantity trigger quality level signal is set unreasonably, and the process quantity fault output does not match the logical action.

[0106] Therefore, the embodiment of the present application realizes the identification and judgment of process quantity signal faults by setting the default value of the process quantity, and corrects and replaces the fault value with the default value that adapts the process state, thereby improving the stability of the steam generator water level control under the random fault mode.

[0107] In the application, the first default value includes but is not limited to the minimum and maximum limits of the transmitter output signal, and the minimum and maximum limits of the transmitter output signal when a fault is detected (used to distinguish normal signals from abnormal signals); the second default value includes but is not limited to the minimum quality bit threshold and the maximum quality bit threshold of the controller received signal (used to identify whether the signal is valid), and the correction and replacement logic taken when the controller detects a fault in the received signal (used to correct or replace the fault value).

[0108] In one embodiment, step S3 specifically further includes:

[0109] Set standards for evaluating venturi tube erosion;

[0110] Conduct erosion assessment on the Venturi tube within a preset time period and obtain corresponding assessment results;

[0111] generating a maintenance strategy for the venturi tube according to the evaluation result;

[0112] Maintaining the venturi tube according to the maintenance strategy, and determining the water level state of the steam generator using the feed water flow rate obtained from the maintained venturi tube;

[0113] According to the water level state, a third water level control of the steam generator is implemented.

[0114] In application, the primary element of the main feedwater flow, the Venturi tube, may be corroded under the long-term action of high-temperature and high-pressure fluid, and may even be perforated. In order to improve the reliability of the Venturi tube and ensure the stability of the water level control of the steam generator, the embodiment of the present application performs a corresponding corrosion assessment on the Venturi tube and adopts an appropriate maintenance strategy to perform timely maintenance on the Venturi tube, thereby ensuring the reliability of the Venturi tube.

[0115] In the application, the preset time period can be set according to actual needs and is not limited here.

[0116] In application, when setting the erosion assessment standard of the Venturi tube, the corresponding erosion assessment standard can be set according to the type of flow meter, and is not limited here.

[0117] In application, when the erosion of the Venturi tube is evaluated within a preset time period, the actual differential pressure value of the Venturi tube can be compared with the preset differential pressure threshold to obtain the corresponding evaluation result and maintenance strategy, that is, when the actual differential pressure value is less than the preset differential pressure threshold, it is prompted that the Venturi tube needs to be replaced; when the actual differential pressure value is greater than or equal to the preset differential pressure threshold, it is prompted that the Venturi tube does not need to be replaced.

[0118] In the application, the preset differential pressure threshold can be calculated based on the relevant parameters of the Venturi tube. The specific calculation formula is:

[0119]

[0120] Where do = θd h , d h is the total thickness of the steel plate at the throat of the Venturi tube, θ is the thickness deviation coefficient, C is the outflow coefficient; ε is the expansion coefficient; D is the inner diameter of the pipe; d is the inner diameter of the throat of the Venturi tube; ρ is the fluid density, q m is the mass flow rate.

[0121] In application, if the Venturi tube does not need to be replaced, the current Venturi tube is used to obtain the water feed flow rate, thereby determining the water level state of the steam generator and realizing water level control of the steam generator.

[0122] The embodiment of the present application ensures the quality of the venturi tube, thereby ensuring the accuracy of the obtained water supply flow rate, and can more accurately obtain the current water level status, which is conducive to achieving more precise water level control and effectively improving the safety and stability of the operation of the nuclear power unit.

[0123] The main feed water flow Venturi tube differential pressure erosion assessment and replacement scheme proposed in the embodiment of the present application dynamically evaluates the degree of erosion of the Venturi tube through differential pressure changes under the conditions of single-cycle erosion and cumulative erosion, thereby improving the stability of steam generator water level control under random failure mode from the perspective of primary element measurement reliability.

[0124] In the low-load operating mode, the embodiment of the present application optimizes the accuracy of the steam-water deviation, the accuracy of the secondary circuit mirror load (narrow range), and the accuracy of the main / bypass valve switching threshold. In the high-load operating mode, the stability of the water level control of the steam generator is achieved by judging the response characteristics of the actuator, the coupling between the main feed water pump speed control system and the main feed water valve opening control system, and the fluctuation of the main feed water process quantity. In the random fault mode, the stability of the water level control of the steam generator is achieved through the precise correction of the steam-water flow rate based on multi-form cross-validation, the setting of the default value of the control system process quantity based on the fault isolation function, and the replacement of the differential pressure erosion of the main water flow Venturi tube, thereby effectively improving the safety and stability of the operation of the nuclear power unit.

[0125] It should be understood that the size of the serial numbers of the steps in the above embodiments does not mean the order of execution. The execution order of each process should be determined by its function and internal logic, and should not constitute any limitation on the implementation process of the embodiments of the present application.

[0126] Embodiment 2

[0127] The present application also provides a water level control device for a steam generator, which is used to execute the method steps in the water level control method embodiment. The device can be a virtual appliance in a terminal device, which is run by a processor of the terminal device, or it can be the terminal device itself.

[0128] like Figure 6 As shown, the water level control device 100 of the steam generator provided in the embodiment of the present application includes a first control module 101 , a second control module 102 , and a third control module 103 .

[0129] A first control module 101 is used to obtain a first target parameter of the steam generator in a low-load operating mode, and to implement a first water level control of the steam generator according to the first target parameter;

[0130] A second control module 102 is used to obtain a second target parameter of the steam generator under a high load operating mode, and implement a second water level control of the steam generator according to the second target parameter;

[0131] A third control module 103 is used to obtain a third target parameter of the steam generator in a random fault mode, and implement a third water level control of the steam generator according to the third target parameter;

[0132] The first target parameter, the second target parameter and the third target parameter are all parameters used to evaluate the water level state of the steam generator.

[0133] In one embodiment, the first control module 101 is further configured to:

[0134] In a preset flow range, obtaining the steam flow and feed water flow of the steam generator;

[0135] If the steam-water deviation between the steam flow rate and the feed water flow rate exceeds a first deviation threshold, optimizing the feed water flow rate and / or the steam flow rate so that the steam-water deviation does not exceed the first deviation threshold;

[0136] Obtain the secondary circuit mirror load and primary circuit thermal power deviation;

[0137] If the power deviation between the secondary-circuit mirror load and the primary-circuit thermal power deviation exceeds a second deviation threshold, the secondary-circuit mirror load is optimized so that the power deviation does not exceed the second deviation threshold.

[0138] In one embodiment, the water level control device 100 further includes a water level fluctuation determination module 104, which is used to:

[0139] In high load working mode, set a fixed sampling period;

[0140] Within n fixed sampling periods, obtaining minimum and maximum water level values ​​and corresponding water level deviations of n groups of steam generators;

[0141] According to the relationship between each group of the water level deviations and the third deviation threshold, it is determined whether the water level of the steam generator oscillates or fluctuates.

[0142] In one embodiment, the second control module 102 is further configured to:

[0143] Acquire a first frequency characteristic and a corresponding first phase difference of a main feedwater pump speed control system, and a second frequency characteristic and a corresponding second phase difference of a main feedwater valve opening control system;

[0144] Obtaining a first regulating parameter of the main feedwater pump speed control system and / or a second regulating parameter of the main feedwater valve opening control system according to the first frequency characteristic, the first phase difference, the second frequency characteristic and the second phase difference;

[0145] The first frequency characteristic and / or the second frequency characteristic are optimized by the first adjustment parameter and / or the second adjustment parameter, so that the water level of the steam generator remains in a stable state.

[0146] In one embodiment, the third control module 103 is further configured to:

[0147] In a random fault mode, obtaining at least one of a steam flow rate, a feedwater flow rate, and a heat balance flow rate;

[0148] Based on the constructed cross-validation system, the differential pressure of the steam flow, the feed water flow and the heat balance flow is corrected with high accuracy;

[0149] Determine the water level state of the steam generator using the corrected steam flow, feed water flow and heat balance flow;

[0150] According to the water level state, a third water level control of the steam generator is implemented.

[0151] In one embodiment, the third control module 103 is further configured to:

[0152] Setting a first default value of the transmitter and a second default value of the controller; the first default value includes a minimum limit value and a maximum limit value of the transmitter output signal, and a minimum limit value and a maximum limit value of the transmitter output signal when a fault is detected; the second default value includes a minimum quality bit threshold value and a maximum quality bit threshold value of the controller receiving signal, and a correction replacement logic taken when the controller detects a receiving signal fault;

[0153] When a receiving signal failure is detected, the receiving signal is corrected and replaced using the correction replacement logic, and the corrected receiving signal is used for water level control.

[0154] In one embodiment, the third control module 103 is further configured to:

[0155] Set standards for evaluating venturi tube erosion;

[0156] Conduct erosion assessment on the Venturi tube within a preset time period and obtain corresponding assessment results;

[0157] generating a maintenance strategy for the venturi tube according to the evaluation result;

[0158] Maintaining the venturi tube according to the maintenance strategy, and determining the water level state of the steam generator using the feed water flow rate obtained from the maintained venturi tube;

[0159] According to the water level state, a third water level control of the steam generator is implemented.

[0160] In application, each unit in the above device may be a software program module, or may be implemented by different logic circuits integrated in a processor or independent physical components connected to a processor, or may be implemented by multiple distributed processors.

[0161] Embodiment 3

[0162] like Figure 7 As shown, the embodiment of the present application further provides a terminal device 200, including: at least one processor 201 ( Figure 7 Only one processor is shown in the figure), memory 202, and a computer program 203 stored in the memory 202 and executable on at least one processor 201. When the processor 201 executes the computer program 203, the steps in the above-mentioned method embodiments are implemented.

[0163] In the application, the terminal device may include, but is not limited to, a processor, a memory, Figure 7 It is only an example of a terminal device and does not constitute a limitation on the terminal device. It may include more or fewer components than shown in the figure, or a combination of certain components, or different components, such as human-computer interaction devices, input and output devices, network access devices, etc. The network access device may include a communication module for the terminal device to communicate with the user terminal.

[0164] In applications, the processor may be a central processing unit (CPU), or other general-purpose processors, digital signal processors (DSP), application-specific integrated circuits (ASIC), field-programmable gate arrays (FPGA) or other programmable logic devices, discrete gate or transistor logic devices, discrete hardware components, etc. For example, the processor may be a timing controller (TCON). A general-purpose processor may be a microprocessor or the processor may be any conventional processor, etc.

[0165] In applications, the memory may be an internal storage unit of a terminal device in some embodiments, for example, a hard disk or memory of the terminal device. The memory may also be an external storage device of the terminal device in other embodiments, for example, a plug-in hard disk, a smart media card (SMC), a secure digital (SD) card, a flash card, etc., equipped on the terminal device. The memory may also include both an internal storage unit of the terminal device and an external storage device. The memory is used to store operating systems, applications, boot loaders, data, and other programs, such as program codes of computer programs. The memory may also be used to temporarily store data that has been output or is to be output.

[0166] In the application, the communication module can be set as any device that can directly or indirectly perform long-distance wired or wireless communication with the user terminal according to actual needs. For example, the communication module can provide communication solutions including wireless local area networks (WLAN) (such as Wi-Fi networks), Bluetooth, Zigbee, mobile communication networks, global navigation satellite systems (GNSS), frequency modulation (FM), near field communication technology (NFC), infrared technology (IR), etc., which are applied to network devices. The communication module may include an antenna, and the antenna may have only one array element or an antenna array including multiple array elements. The communication module can receive electromagnetic waves through the antenna, frequency modulate and filter the electromagnetic wave signals, and send the processed signals to the processor. The communication module can also receive the signal to be sent from the processor, frequency modulate and amplify it, and convert it into electromagnetic waves for radiation through the antenna.

[0167] It should be noted that the information interaction, execution process, etc. between the above-mentioned devices / modules are based on the same concept as the method embodiment of the present application. Their specific functions and technical effects can be found in the method embodiment part and will not be repeated here.

[0168] Those skilled in the art can clearly understand that, for the convenience and simplicity of description, only the division of the above-mentioned functional modules is used as an example for illustration. In actual applications, the above-mentioned function allocation can be completed by different functional modules as needed, that is, the internal structure of the device can be divided into different functional modules to complete all or part of the functions described above. The functional modules in the embodiment can be integrated into a processing module, or each module can exist physically separately, or two or more modules can be integrated into one module. The above-mentioned integrated modules can be implemented in the form of hardware or in the form of software functional modules. In addition, the specific names of the functional modules are only for the convenience of distinguishing each other, and are not used to limit the scope of protection of this application. The specific working process of the modules in the above-mentioned system can refer to the corresponding process in the aforementioned method embodiment, which will not be repeated here.

[0169] The embodiment of the present application further provides a computer-readable storage medium, in which a computer program is stored. When the computer program is executed by a processor, the steps in the above-mentioned method embodiments can be implemented.

[0170] An embodiment of the present application provides a computer program product. When the computer program product runs on a terminal device, the terminal device can implement the steps in the above-mentioned various method embodiments.

[0171] If the integrated module is implemented in the form of a software function module and sold or used as an independent product, it can be stored in a computer-readable storage medium. Based on this understanding, the present application implements all or part of the processes in the above-mentioned embodiment method, which can be completed by instructing the relevant hardware through a computer program, and the computer program can be stored in a computer-readable storage medium. When the computer program is executed by the processor, the steps of the above-mentioned various method embodiments can be implemented. Among them, the computer program includes computer program code, and the computer program code can be in source code form, object code form, executable file or some intermediate form. The computer-readable medium may include at least: any entity or device capable of carrying the computer program code to the terminal device, a recording medium, a computer memory, a read-only memory (ROM), a random access memory (RAM), an electric carrier signal, a telecommunication signal, and a software distribution medium. For example, a USB flash drive, a mobile hard disk, a disk or an optical disk.

[0172] In the above embodiments, the description of each embodiment has its own emphasis. For parts that are not described or recorded in detail in a certain embodiment, reference can be made to the relevant descriptions of other embodiments.

[0173] Those of ordinary skill in the art will appreciate that the modules and algorithm steps of each example described in conjunction with the embodiments disclosed herein can be implemented in electronic hardware, or a combination of computer software and electronic hardware. Whether these functions are performed in hardware or software depends on the specific application and design constraints of the technical solution. Professional and technical personnel can use different methods to implement the described functions for each specific application, but such implementation should not be considered to be beyond the scope of this application.

[0174] In the embodiments provided in the present application, it should be understood that the disclosed devices and methods can be implemented in other ways. For example, the device embodiments described above are only schematic. For example, the division of the modules is only a logical function division. There may be other division methods in actual implementation, such as multiple modules or components can be combined or integrated into another system, or some features can be ignored or not executed. Another point is that the mutual coupling or direct coupling or communication connection shown or discussed can be through some interfaces, indirect coupling or communication connection of devices or modules, which can be electrical, mechanical or other forms.

[0175] The modules described as separate components may or may not be physically separated, and the components shown as modules may or may not be physical modules, that is, they may be located in one place or distributed on multiple network modules. Some or all of the modules may be selected according to actual needs to achieve the purpose of the solution of this embodiment.

[0176] The embodiments described above are only used to illustrate the technical solutions of the present application, rather than to limit them. Although the present application has been described in detail with reference to the aforementioned embodiments, a person skilled in the art should understand that the technical solutions described in the aforementioned embodiments may still be modified, or some of the technical features may be replaced by equivalents. Such modifications or replacements do not deviate the essence of the corresponding technical solutions from the spirit and scope of the technical solutions of the embodiments of the present application, and should all be included in the protection scope of the present application.

Claims

1. A water level control method for a steam generator, characterized in that: The water level control method comprises: In a low-load operating mode, obtaining a first target parameter of the steam generator, and implementing a first water level control of the steam generator according to the first target parameter; Under the high load working mode, obtaining a second target parameter of the steam generator, and implementing a second water level control of the steam generator according to the second target parameter; In a random fault mode, obtaining a third target parameter of the steam generator, and implementing a third water level control of the steam generator according to the third target parameter; The first target parameter, the second target parameter and the third target parameter are all parameters used to evaluate the water level state of the steam generator.

2. The water level control method according to claim 1, characterized in that: The method of obtaining a first target parameter of the steam generator in the low load operating mode and implementing a first water level control of the steam generator according to the first target parameter includes: In a preset flow range, obtaining the steam flow and feed water flow of the steam generator; If the steam-water deviation between the steam flow rate and the feed water flow rate exceeds a first deviation threshold, optimizing the feed water flow rate and / or the steam flow rate so that the steam-water deviation does not exceed the first deviation threshold; Obtain the secondary circuit mirror load and primary circuit thermal power deviation; If the power deviation between the secondary-circuit mirror load and the primary-circuit thermal power deviation exceeds a second deviation threshold, the secondary-circuit mirror load is optimized so that the power deviation does not exceed the second deviation threshold.

3. The water level control method according to claim 1, characterized in that: Before obtaining the second target parameter of the steam generator under the high load working mode and implementing the second water level control of the steam generator according to the second target parameter, the method includes: In high load working mode, set a fixed sampling period; Within n fixed sampling periods, obtaining minimum and maximum water level values ​​and corresponding water level deviations of n groups of steam generators; According to the relationship between each group of the water level deviations and the third deviation threshold, it is determined whether the water level of the steam generator oscillates or fluctuates.

4. The water level control method according to claim 3, characterized in that: The method of obtaining a second target parameter of the steam generator under the high load working mode and implementing a second water level control of the steam generator according to the second target parameter includes: Acquire a first frequency characteristic and a corresponding first phase difference of a main feedwater pump speed control system, and a second frequency characteristic and a corresponding second phase difference of a main feedwater valve opening control system; Obtaining a first regulating parameter of the main feedwater pump speed control system and / or a second regulating parameter of the main feedwater valve opening control system according to the first frequency characteristic, the first phase difference, the second frequency characteristic and the second phase difference; The first frequency characteristic and / or the second frequency characteristic are optimized by the first adjustment parameter and / or the second adjustment parameter, so that the water level of the steam generator remains in a stable state.

5. The water level control method according to claim 1, characterized in that: The method of acquiring a third target parameter of the steam generator in the random fault mode and implementing a third water level control of the steam generator according to the third target parameter includes: In a random fault mode, obtaining at least one of a steam flow rate, a feedwater flow rate, and a heat balance flow rate; Based on the constructed cross-validation system, the differential pressure of the steam flow, the feed water flow and the heat balance flow is corrected with high accuracy; Determine the water level state of the steam generator using the corrected steam flow, feed water flow and heat balance flow; According to the water level state, a third water level control of the steam generator is implemented.

6. The water level control method according to claim 5, characterized in that: The step of obtaining a third target parameter of the steam generator in the random fault mode and implementing a third water level control of the steam generator according to the third target parameter further includes: Setting a first default value of the transmitter and a second default value of the controller; the first default value includes a minimum limit value and a maximum limit value of the transmitter output signal, and a minimum limit value and a maximum limit value of the transmitter output signal when a fault is detected; the second default value includes a minimum quality bit threshold value and a maximum quality bit threshold value of the controller receiving signal, and a correction replacement logic taken when the controller detects a receiving signal fault; When a receiving signal failure is detected, the receiving signal is corrected and replaced using the correction replacement logic, and the corrected receiving signal is used for water level control.

7. The water level control method according to claim 6, characterized in that: The step of obtaining a third target parameter of the steam generator in the random fault mode and implementing a third water level control of the steam generator according to the third target parameter further includes: Set standards for evaluating venturi tube erosion; Conduct erosion assessment on the Venturi tube within a preset time period and obtain corresponding assessment results; generating a maintenance strategy for the venturi tube according to the evaluation result; Maintaining the venturi tube according to the maintenance strategy, and determining the water level state of the steam generator using the feed water flow rate obtained from the maintained venturi tube; According to the water level state, a third water level control of the steam generator is implemented.

8. A water level control device for a steam generator, characterized in that: The water level control device comprises: a first control module, configured to obtain a first target parameter of the steam generator in a low-load operating mode, and implement a first water level control of the steam generator according to the first target parameter; a second control module, configured to obtain a second target parameter of the steam generator under a high load operating mode, and implement a second water level control of the steam generator according to the second target parameter; a third control module, configured to obtain a third target parameter of the steam generator in a random fault mode, and implement a third water level control of the steam generator according to the third target parameter; The first target parameter, the second target parameter and the third target parameter are all parameters used to evaluate the water level state of the steam generator.

9. A terminal device, comprising a memory, a processor, and a computer program stored in the memory and executable on the processor, characterized in that: When the processor executes the computer program, the steps of the water level control method according to any one of claims 1 to 7 are implemented.

10. A computer-readable storage medium storing a computer program, characterized in that: When the computer program is executed by a processor, the steps of the water level control method according to any one of claims 1 to 7 are implemented.

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