Method and device for predicting opening degree of main water feeding valve and control system

Abstract

The invention relates to a method and device for predicting the opening degree of a main water feeding valve and a control system. The method comprises the steps that under the condition that a fault main water supply valve is detected, the current state of the fault main water supply valve is determined according to the difference value between the water level of each evaporator and the water level fixed value of the evaporator and the water level change rate of a non-fault evaporator; under the condition that the current state of the fault main water supply valve is a steady state, the average value of the opening degrees of non-fault main water supply valves is obtained and serves as the predicted opening degree of the fault main water supply valve; and under the condition that the current state of the fault main feed water valve is not the steady state, the predicted opening degree of the fault main feed water valve is determined according to the function relation between the sectional area of the main feed water valve and the predicted opening degree of the main feed water valve and the sectional area of the main feed water valve of the fault main feed water valve. The method can determine the actual opening degree of the fault main water supply valve so as to guarantee safe and stable operation of a nuclear power unit.

Description

Technical Field

[0001] The present application relates to the technical field of evaporator water level control, and in particular to a method, device and control system for predicting the opening of a main water supply valve. Background Art

[0002] As one of the most critical and sensitive control systems in nuclear power plants, the stability of the evaporator water level control system is crucial for the safe and stable operation of nuclear power units. Statistics show that abnormal evaporator water level control is the leading cause of unit transients or automatic reactor shutdowns. In existing evaporator water level control systems, abnormal operation of the back-end actuators often leads to disturbances or transients in the control system.

[0003] The actuator at the back end of the evaporator water level control system is the main water supply valve. The most common failure mode is a stuck valve, where the main water supply valve becomes stuck at a specific opening, rendering both automatic and manual control functions unavailable. The second failure mode is when the valve is not controlled by the command signal and continuously opens or closes.

[0004] In the main feedwater valve failure mode, the actual valve opening is unknown. Therefore, the research on the method of judging the actual valve opening in the evaporator water level main feedwater valve failure mode of nuclear power plants has very important engineering significance, which is conducive to fault response and fault handling, and ensures the safe and stable operation of nuclear power units. Summary of the Invention

[0005] Based on this, it is necessary to provide a main feedwater valve opening prediction method, device and control system that can determine the actual opening of the faulty main feedwater valve to ensure the safe and stable operation of the nuclear power unit in response to the above technical problems.

[0006] In a first aspect, a method for predicting the opening of a main water supply valve is provided, which is applied to an evaporator water level control system. The method comprises:

[0007] In the event that a faulty main water supply valve is detected, the current state of the faulty main water supply valve is determined based on the difference between the water level of each evaporator and the evaporator water level set value and the water level change rate of the non-faulty evaporator;

[0008] When the current state of the faulty main water supply valve is steady, the average value of the opening of the non-faulty main water supply valve is obtained and used as the predicted opening of the faulty main water supply valve;

[0009] When the current state of the faulty main water supply valve is not steady state, the predicted opening of the faulty main water supply valve is determined based on the functional relationship between the main water supply valve cross-sectional area and the predicted opening of the main water supply valve and the main water supply valve cross-sectional area of ​​the faulty main water supply valve.

[0010] In one embodiment, the process of determining the cross-sectional area of ​​the main water supply valve includes:

[0011] Determine the main water supply flow rate based on the pressure difference before and after the main water supply valve; wherein the pressure difference before and after the main water supply valve refers to the difference between the water inlet pressure before the main water supply valve fails and the water inlet pressure after the failure, or the difference between the water outlet pressure before and after the main water supply valve fails;

[0012] The cross-sectional area of ​​the main water supply valve is determined according to the functional relationship among the main water supply flow rate and the main water supply flow velocity, the main water supply flow rate and the main water supply flow velocity.

[0013] In one embodiment, the process of determining the pressure difference before and after the main water supply valve includes:

[0014] Obtain the potential difference between the feedwater pump outlet and the steam generator feedwater inlet;

[0015] Obtain the pressure difference between the water main and the steam main;

[0016] Based on the mapping relationship between the secondary circuit load and the pressure difference, a first pressure drop on the secondary side of the steam generator and a second pressure drop in the steam pipeline and / or the feedwater pipeline are obtained by fitting;

[0017] The pressure difference before and after the main feedwater valve is determined based on the pressure difference between the feedwater main pipe and the steam main pipe, the potential difference between the feedwater pump outlet and the steam generator feedwater inlet, the first pressure drop and the second pressure drop.

[0018] In one embodiment, determining the main water supply flow rate according to the pressure difference before and after the main water supply valve includes:

[0019] Obtain the product value of the preset constant, the pressure difference before and after the main water supply valve, and the acceleration of gravity;

[0020] Obtaining the square root of the product value;

[0021] The product value between the flow coefficient and the square root value is obtained and used as the main feed water flow rate.

[0022] In one embodiment, the process of determining whether the current state of the faulty main water supply valve is a steady state includes:

[0023] When at least one of the following conditions is met, the current state of the faulty main water supply valve is determined to be steady state; the following conditions include that the water level change rate of the non-faulty evaporator is not greater than the standard value of the water level change rate of the non-faulty evaporator, and the absolute value of the difference between the water level of each evaporator and the evaporator water level set value is not greater than the standard value of the non-faulty evaporator water level deviation.

[0024] In one embodiment, the method further comprises:

[0025] Adjust the evaporator water level corresponding to the faulty main water supply valve according to the predicted opening determined when the current state of the faulty main water supply valve is steady state;

[0026] If the evaporator water level does not reach the preset water level within the preset time after adjustment, the evaporator water level corresponding to the faulty main water supply valve is adjusted according to the predicted opening determined when the current state of the faulty main water supply valve is not steady state.

[0027] In a second aspect, a main water supply valve opening prediction device is provided, which is applied to an evaporator water level control system, and the device includes:

[0028] a state determination module for determining the current state of the faulty main water supply valve based on the difference between the water level of each evaporator and the evaporator water level set value and the water level change rate of the non-faulty evaporator when a faulty main water supply valve is detected;

[0029] An opening prediction module is used to use the average opening of the main water supply valve of the non-faulty evaporator as the predicted opening of the faulty main water supply valve when the current state of the faulty main water supply valve is steady;

[0030] The opening prediction module is also used to determine the predicted opening of the faulty main water supply valve based on the functional relationship between the main water supply valve cross-sectional area and the predicted opening of the main water supply valve and the main water supply valve cross-sectional area of ​​the faulty main water supply valve when the current state of the faulty main water supply valve is not steady state.

[0031] In a third aspect, an evaporator water level control system is provided, comprising a memory and a processor, wherein the memory stores a computer program, and the processor implements the steps of the method described in the first aspect when executing the computer program.

[0032] According to a fourth aspect, a computer-readable storage medium is provided, on which a computer program is stored. When the computer program is executed by a processor, the steps of the method described in the first aspect are implemented.

[0033] According to a fourth aspect, a computer program product is provided, comprising a computer program, wherein when the computer program is executed by a processor, the steps of the method described in the first aspect are implemented.

[0034] In the above embodiment, in the main water supply valve fault mode, it is determined whether the main water supply valve is in a steady state. In the steady state, the opening of the faulty main water supply valve is predicted by the opening of the non-faulty main water supply valve, which is extremely simple. In the non-steady state, the predicted opening of the faulty main water supply valve is determined based on the functional relationship between the main water supply valve cross-sectional area and the predicted main water supply valve opening and the main water supply valve cross-sectional area of ​​the faulty main water supply valve, so that the actual valve opening in the main water supply valve fault mode can be timely determined. Understanding the actual valve opening in the main water supply valve fault mode is beneficial to fault response and fault handling.

[0035] Furthermore, the method provided in this embodiment can improve the reliability of the evaporator water level control system, significantly reducing evaporator water level disturbances caused by main feedwater valve anomalies, significantly reducing the risk of reactor automatic shutdowns due to main feedwater valve anomalies, and ensuring the safe and stable operation of nuclear power units. Furthermore, the method provided in this embodiment has significant prospects for promotion and application. The technology involved in this project has good versatility and can be promoted and applied to nuclear power units at multiple sites. BRIEF DESCRIPTION OF THE DRAWINGS

[0036] In order to more clearly illustrate the technical solutions in the embodiments of the present application or related technologies, the following briefly introduces the drawings required for use in the embodiments of the present application or related technical descriptions. Obviously, the drawings described below are only some embodiments of the present application. For ordinary technicians in this field, other related drawings can be obtained based on these drawings without paying any creative work.

[0037] Figure 1 Schematic diagram of a flow chart of a method for predicting the opening of a main water supply valve in one embodiment;

[0038] Figure 2 Another schematic flow chart of a method for predicting the opening of a main water supply valve in one embodiment;

[0039] Figure 3 2 is a flow chart of a method for predicting the opening of a main water supply valve in one embodiment;

[0040] Figure 4 Schematic diagram of the steam-water pressure difference in one embodiment;

[0041] Figure 5 A curve diagram showing a judgment of a steady-state value of the actual valve opening under a main water supply valve failure mode in one embodiment;

[0042] Figure 6 1 is a structural block diagram of a main water supply valve opening prediction device in one embodiment. DETAILED DESCRIPTION

[0043] In order to make the purpose, technical solutions and advantages of this application more clear, the following further describes this application in detail with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are only used to explain this application and are not intended to limit this application.

[0044] The steam generator is a vertical, natural circulation device that produces saturated steam. Reactor coolant flows within the heat transfer tubes, transferring heat to the secondary water circuit outside the tubes. This secondary water circulates naturally within the steam generator, and as it flows through the heat transfer tubes, a portion of it becomes saturated steam, which is then supplied to the main steam turbine and auxiliary facilities. The steam generator water level control system maintains the water level on the secondary side of the steam generator at the required set value. Evaporator water level control primarily involves controlling the speed of the main feedwater pump and the opening of the main feedwater valve. The control system primarily consists of the evaporator, main feedwater pump, main feedwater valve, and associated piping.

[0045] The evaporator water level control system is one of the most critical and sensitive control systems in a nuclear power plant. Its control stability is crucial for the safe and stable operation of nuclear power units. Statistics show that abnormal evaporator water level control is the leading cause of unit transients or automatic reactor shutdowns. Existing evaporator water level control systems feature redundant front-end sensors and intermediate controllers, significantly improving the reliability of both front-end and intermediate links. However, the non-redundant back-end actuators remain a weak link. Abnormal operation of these back-end actuators often leads to disturbances or transients in the control system.

[0046] The actuator at the back end of the evaporator water level control system is the main feedwater valve, which is essentially a pneumatic control valve. The most common failure mode is a stuck valve, where the main feedwater valve becomes stuck at a specific opening, rendering both automatic and manual control functions unavailable. The second failure mode is when the valve is not controlled by the command signal and continues to open or close. Nuclear power plants at home and abroad have repeatedly experienced evaporator water level control anomalies due to failures in the main feedwater valve, the actuator at the back end of the control system, which has seriously triggered automatic reactor shutdowns. The response time allowed for operators after a main feedwater valve failure is very limited; in most cases, the time span from failure occurrence to automatic reactor shutdown is ≤10 minutes.

[0047] After selecting typical fault data for analysis, it can be concluded that when the main water supply valve fails, the actual opening of the main water supply valve is smaller than the required opening. Small, and the pressure difference between steam and water Basically remain unchanged, resulting in water flow The evaporator water level drops Continue to decline, evaporator water level Evaporator water level setting The deviation gradually expands. Main water supply valve opening demand signal Under the action of the integral of the regulating system, it continues to open and reaches the maximum opening of 100%. Since the actual opening of the main feedwater valve has not actually changed, if certain intervention measures are not taken, the evaporator water level reactor protection logic will be directly triggered. Among them, nuclear power unit B triggered the reactor automatic shutdown signal. When the main feedwater valve fails, the actual opening of the main feedwater valve is larger than the required opening. There may be a situation where it is too small, and there may also be a situation where it is too large. Therefore, the main water supply valve opening demand signal Under the integral action of the regulating system, the water level in the evaporator is continuously opened or closed. The choice of opening or closing direction is correlated with the instantaneous steam-water deviation of the valve. There are also significant differences in the rate of change.

[0048] Since the actual valve opening is unknown when the main feedwater valve is in failure mode, the research on the method for determining the actual valve opening under the failure mode of the main feedwater valve of the evaporator water level in a nuclear power plant has very important engineering significance, which is beneficial to fault response and fault handling, and ensures the safe and stable operation of the nuclear power unit.

[0049] Based on this, the present application provides a main water supply valve opening prediction method, device and control system.

[0050] The following non-faulty evaporator refers to the evaporator corresponding to the non-faulty feedwater valve, and the following faulty evaporator refers to the evaporator corresponding to the faulty feedwater valve. Similarly, the following non-faulty main feedwater valve refers to the main feedwater valve corresponding to the non-faulty evaporator, and the following faulty main feedwater valve refers to the main feedwater valve corresponding to the faulty evaporator.

[0051] In an exemplary embodiment, Figure 1 As shown, a method for predicting the opening of a main water supply valve is provided, which is described by taking the method applied to the above-mentioned evaporator water level control system as an example, and includes the following steps 102 to 106. Among them:

[0052] Step 102 : When a faulty main water supply valve is detected, the current state of the faulty main water supply valve is determined based on the difference between the water level of each evaporator and the evaporator water level set value and the water level change rate of the non-faulty evaporator.

[0053] The current state includes a steady state and an unsteady state. This step is used to determine whether the faulty main water supply valve is in a steady state.

[0054] When a main water supply valve fault signal is detected, the faulty main water supply valve corresponding to the main water supply valve fault signal and the faulty evaporator corresponding to the faulty main water supply valve can be determined.

[0055] Among them, the evaporator water level set value can be set according to actual needs.

[0056] In some embodiments, the main water supply valve is determined to be in a steady state if the water level change rate of the non-faulty evaporator is less than a preset change rate, and the difference between the water level of each evaporator and the evaporator water level set value is less than a preset difference. In some embodiments, the main water supply valve is determined to be in an unsteady state if the water level change rate of the non-faulty evaporator is greater than or equal to a preset change rate, and / or the difference between the water level of any evaporator and the evaporator water level set value is greater than or equal to a preset difference.

[0057] Step 104 : When the current state of the faulty main water supply valve is steady, obtain the average value of the opening of the non-faulty main water supply valve and use it as the predicted opening of the faulty main water supply valve.

[0058] For example, if there are three main water supply valves in total, one of which is a faulty main water supply valve and two are not faulty main water supply valves, the average opening of the two non-faulty main water supply valves is used as the predicted opening of the faulty main water supply valve. , where It is the opening signal of the non-fault main water supply valve corresponding to the non-faulty No. 1 evaporator. It is the opening signal of the main water supply valve corresponding to the non-faulty No. 2 evaporator. The predicted opening of the faulty main water supply valve.

[0059] Step 106, when the current state of the faulty main water supply valve is not steady state, determine the predicted opening of the faulty main water supply valve according to the functional relationship between the main water supply valve cross-sectional area and the predicted opening of the main water supply valve and the main water supply valve cross-sectional area of ​​the faulty main water supply valve.

[0060] Among them, the cross-sectional area of ​​the main water supply valve refers to the area of ​​the internal flow channel of the valve at a certain specific cross-section.

[0061] The cross-sectional area of ​​the main water supply valve of the faulty main water supply valve can be obtained by actual measurement or simulation, for example, by calculating the cross-sectional area of ​​the main water supply valve based on the main water supply flow rate and flow velocity.

[0062] The functional relationship between the main water supply valve cross-sectional area and the main water supply valve predicted opening can be obtained by fitting based on historical data. Predicted opening of main water supply valve The corresponding functional relationship is as follows: .in, The opening characteristics of the main water supply valve, that is, the main water supply valve opening instruction signal (in this embodiment, it can be understood as the predicted opening) and the main water supply valve cross-sectional area The corresponding function relationship can be obtained by fitting a high-order function to ensure accuracy. .

[0063] The predicted opening of the faulty main water supply valve determined in step 106 can be understood as the initial value of the actual valve opening under the main water supply valve fault mode. This initial value determination of the actual valve opening under the main water supply valve fault mode is primarily used to promptly determine the actual valve opening under the main water supply valve fault mode in the early stages of a main water supply valve fault.

[0064] The predicted opening of the faulty main water supply valve determined in step 104 can be understood as the actual valve opening value under the main water supply valve fault mode accurately determined after the evaporator water level control is stabilized.

[0065] In the above embodiment, in the main water supply valve fault mode, it is determined whether the main water supply valve is in a steady state. In the steady state, the opening of the faulty main water supply valve is predicted by the opening of the non-faulty main water supply valve, which is extremely simple. In the non-steady state, the predicted opening of the faulty main water supply valve is determined based on the functional relationship between the main water supply valve cross-sectional area and the predicted main water supply valve opening and the main water supply valve cross-sectional area of ​​the faulty main water supply valve, so that the actual valve opening in the main water supply valve fault mode can be timely determined. Understanding the actual valve opening in the main water supply valve fault mode is beneficial to fault response and fault handling.

[0066] Furthermore, the method provided in this embodiment can improve the reliability of the evaporator water level control system, significantly reducing evaporator water level disturbances caused by main feedwater valve anomalies, significantly reducing the risk of reactor automatic shutdowns due to main feedwater valve anomalies, and ensuring the safe and stable operation of nuclear power units. Furthermore, the method provided in this embodiment has significant prospects for promotion and application. The technology involved in this project has good versatility and can be promoted and applied to nuclear power units at multiple sites.

[0067] For some examples, see Figure 2 , the process of determining the cross-sectional area of ​​the main water supply valve includes:

[0068] Step 202, determine the main water supply flow rate based on the pressure difference before and after the main water supply valve; wherein, the pressure difference before and after the main water supply valve refers to the difference between the water inlet pressure before the main water supply valve fails and the water inlet pressure after the failure, or the difference between the water outlet pressure before and after the main water supply valve fails.

[0069] In one embodiment, the functional relationship between the pressure difference before and after the main water supply valve and the main water supply flow rate can be obtained by fitting historical data, and then the main water supply flow rate can be determined based on the functional relationship between the pressure difference before and after the main water supply valve and the main water supply flow rate and the calculated pressure difference before and after the main water supply valve.

[0070] In one embodiment, the product of the preset constant, the pressure difference before and after the main water supply valve and the acceleration of gravity is obtained; the square root of the product is obtained; the product of the flow coefficient and the square root is obtained and used as the main water supply flow rate. For example, the main water supply flow rate Pressure difference before and after the main water supply valve The corresponding functional relationship is as follows: .in, is the flow coefficient of the fluid, Represents the acceleration due to gravity.

[0071] Step 204 : determining the main water supply valve cross-sectional area according to the functional relationship among the main water supply valve cross-sectional area, the main water supply flow rate and the main water supply flow rate, the main water supply flow rate and the main water supply flow rate.

[0072] According to the principles of fluid mechanics, the main water flow rate is established Cross-sectional area of ​​main water supply valve and main feed water flow rate The functional relationship is: Based on this functional relationship, the main water supply flow rate calculated in step 202 and the measured main water supply flow rate, the main water supply valve cross-sectional area can be determined. . Determine the cross-sectional area of ​​the main water supply valve Used in step 106 to determine the predicted opening of the faulty main water supply valve.

[0073] The above embodiment determines the cross-sectional area of ​​the main water supply valve based on the functional relationship among the cross-sectional area of ​​the main water supply valve, the main water supply flow rate and the main water supply flow rate, and the main water supply flow rate. The method is simple and efficient, and the cross-sectional area of ​​the main water supply valve can be easily and quickly calculated.

[0074] For some examples, see Figure 3 , the process of determining the pressure difference before and after the main water supply valve includes:

[0075] Step 302: Obtain the potential difference between the feedwater pump outlet and the steam generator feedwater inlet.

[0076] Step 304: Obtain the pressure difference between the water main pipe and the steam main pipe.

[0077] Step 306: Based on the mapping relationship between the secondary circuit load and the pressure difference, obtain a first pressure drop on the secondary side of the steam generator and a second pressure drop in the steam pipeline and / or the feedwater pipeline by fitting.

[0078] Step 308: Determine the pressure difference before and after the main feedwater valve according to the pressure difference between the feedwater main pipe and the steam main pipe, the potential difference between the feedwater pump outlet and the steam generator feedwater inlet, the first pressure drop, and the second pressure drop.

[0079] The initial value of the actual valve opening is determined in the main feedwater valve failure mode. The variables involved in the calculation are the steam-water pressure difference. and main feed water flow , the actual valve opening in the main water supply valve fault mode is obtained by pressure difference opening calculation.

[0080] See Figure 4 The steam-water pressure difference shown (i.e. the pressure difference between the water main pipe and the steam main pipe) composition diagram, steam-water pressure difference It consists of four parts ( 、 、 and )composition. It is the potential difference between the feedwater pump outlet and the steam generator feedwater inlet, which is a constant value. It is the pressure difference before and after the main water supply valve. is the pressure drop on the secondary side of the steam generator (i.e., the first pressure drop), which changes with the load, that is, it conforms to the mapping relationship , Represents the secondary circuit load. The first pressure drop remains constant at a stable load platform. is the pressure drop in the steam pipeline and the water supply pipeline (i.e., the second pressure drop), which changes with the load, that is, it conforms to the mapping relationship .

[0081] In order to ensure higher accuracy, 、 All of them are obtained by fitting high-order functions.

[0082] The pressure difference before and after the main water supply valve can be obtained through the above composition : .

[0083] The above embodiment obtains the functional relationship between the pressure difference before and after the main water supply valve and the main water supply flow rate through simulation, and the steam-water pressure difference The functional relationship between the other components in the main feedwater valve (i.e., the pressure difference between the water supply main pipe and the steam main pipe) and the pressure difference before and after the main feedwater valve is used to quickly obtain the main feedwater flow rate based on the measured data and the functional relationship.

[0084] In some embodiments, the process of determining whether the current state of the faulty main water supply valve is a steady state includes:

[0085] When at least one of the following conditions is met, the current state of the faulty main water supply valve is determined to be steady state; the following conditions include that the water level change rate of the non-faulty evaporator is not greater than the standard value of the water level change rate of the non-faulty evaporator, and the absolute value of the difference between the water level of each evaporator and the evaporator water level set value is not greater than the standard value of the non-faulty evaporator water level deviation.

[0086] That is to say, if the following three conditions are met at the same time, it is judged that the evaporator water level has entered a steady-state value and the current state of the faulty main water supply valve is steady-state.

[0087] The three conditions include: ; ; .

[0088] in, is the standard value of the water level change rate of a non-faulty evaporator, which is obtained by multiplying the maximum change rate of the evaporator water level during full-power steady-state operation by the uncertainty coefficient. is the standard value of the non-fault evaporator water level deviation, which is obtained by multiplying the maximum deviation of the evaporator water level during full-power steady-state operation by the uncertainty coefficient.

[0089] See Figure 5 The actual valve opening steady-state value judgment curve diagram under the main water supply valve fault mode is shown. If the non-fault evaporator water level does not change significantly, that is, there is no obvious upward or downward trend, and the fault evaporator and non-fault evaporator water levels are the same as the evaporator water level set value If the values ​​match, it is determined that the evaporator water level has entered a steady-state value.

[0090] In the above embodiment, whether the evaporator water level is stably controlled is determined to determine whether the main water supply valve enters a steady state under the fault mode. This method is stable and reliable and is conducive to accurately determining the state of the faulty main water supply valve.

[0091] In some embodiments, the main water supply valve opening prediction method further includes:

[0092] Step 1: Adjust the evaporator water level corresponding to the faulty main water supply valve according to the predicted opening determined when the current state of the faulty main water supply valve is steady state.

[0093] From the above description, it can be seen that the predicted opening determined when the faulty main water supply valve is currently in a steady state is more accurate. Therefore, the evaporator water level is preferably adjusted based on the predicted opening determined when the faulty main water supply valve is currently in a steady state.

[0094] Step 2: If the evaporator water level does not reach the preset water level within the preset time after adjustment, the evaporator water level corresponding to the faulty main water supply valve is adjusted according to the predicted opening determined when the current state of the faulty main water supply valve is not steady state.

[0095] The preset water level may be understood as a preset water level range.

[0096] If the evaporator water level has not reached the preset water level after adjustment based on the predicted opening corresponding to the steady state, the evaporator water level is adjusted using the predicted opening determined when the state is not steady.

[0097] In the above embodiment, the knowledge of the actual valve opening in the main water supply valve fault mode is helpful for timely adjustment of the evaporator water level and faster fault response and handling.

[0098] It should be understood that, although the various steps in the flowcharts involved in the various embodiments as above are shown in sequence according to the instructions of the arrows, these steps are not necessarily performed in sequence in the order indicated by the arrows. Unless otherwise specified herein, there is no strict order restriction on the execution of these steps, and these steps can be performed in other orders. Moreover, at least a portion of the steps in the flowcharts involved in the various embodiments as above can include multiple steps or multiple stages, and these steps or stages are not necessarily performed at the same time, but can be performed at different times, and the execution order of these steps or stages is not necessarily performed in sequence, but can be performed in turn or alternately with other steps or at least a portion of the steps or stages in other steps.

[0099] See Figure 6 Based on the same inventive concept, the present application also provides a main water supply valve opening prediction device 60 for implementing the main water supply valve opening prediction method mentioned above. The solution provided by this device is similar to the solution described in the above method. Therefore, the specific limitations of one or more embodiments of the main water supply valve opening prediction device 60 provided below can be found in the above-mentioned limitations of the main water supply valve opening prediction method and will not be repeated here.

[0100] The main water supply valve opening prediction device 60 is applied to the evaporator water level control system. The device 60 includes:

[0101] The state determination module 61 is used to determine the current state of the faulty main water supply valve according to the difference between the water level of each evaporator and the evaporator water level set value and the water level change rate of the non-faulty evaporator when a faulty main water supply valve is detected.

[0102] The opening prediction module 62 is configured to use the average opening of the main water supply valves of the non-faulty evaporators as the predicted opening of the faulty main water supply valve when the current state of the faulty main water supply valve is steady.

[0103] The opening prediction module 62 is also used to determine the predicted opening of the faulty main water supply valve based on the functional relationship between the main water supply valve cross-sectional area and the predicted opening of the main water supply valve and the main water supply valve cross-sectional area of ​​the faulty main water supply valve when the current state of the faulty main water supply valve is not steady state.

[0104] In one embodiment, the process of determining the cross-sectional area of ​​the main water supply valve includes:

[0105] Determine the main water supply flow rate based on the pressure difference before and after the main water supply valve; wherein the pressure difference before and after the main water supply valve refers to the difference between the water inlet pressure before the main water supply valve fails and the water inlet pressure after the failure, or the difference between the water outlet pressure before and after the main water supply valve fails;

[0106] The cross-sectional area of ​​the main water supply valve is determined according to the functional relationship among the main water supply flow rate and the main water supply flow velocity, the main water supply flow rate and the main water supply flow velocity.

[0107] In one embodiment, the process of determining the pressure difference before and after the main water supply valve includes:

[0108] Obtain the potential difference between the feedwater pump outlet and the steam generator feedwater inlet;

[0109] Obtain the pressure difference between the water main and the steam main;

[0110] Based on the mapping relationship between the secondary circuit load and the pressure difference, a first pressure drop on the secondary side of the steam generator and a second pressure drop in the steam pipeline and / or the feedwater pipeline are obtained by fitting;

[0111] The pressure difference before and after the main feedwater valve is determined based on the pressure difference between the feedwater main pipe and the steam main pipe, the potential difference between the feedwater pump outlet and the steam generator feedwater inlet, the first pressure drop and the second pressure drop.

[0112] In one embodiment, determining the main water supply flow rate according to the pressure difference before and after the main water supply valve includes:

[0113] Obtain the product value of the preset constant, the pressure difference before and after the main water supply valve, and the acceleration of gravity;

[0114] Get the square root of the product value;

[0115] The product value between the flow coefficient and the square root value is obtained and used as the main water supply flow rate.

[0116] In one embodiment, the process of determining whether the current state of the faulty main water supply valve is a steady state includes:

[0117] When at least one of the following conditions is met, the current state of the faulty main water supply valve is determined to be steady state; the following conditions include that the water level change rate of the non-faulty evaporator is not greater than the standard value of the water level change rate of the non-faulty evaporator, and the absolute value of the difference between the water level of each evaporator and the evaporator water level set value is not greater than the standard value of the non-faulty evaporator water level deviation.

[0118] In one embodiment, the main water supply valve opening prediction device 60 further includes an adjustment module 63. The adjustment module 63 is configured to adjust the evaporator water level corresponding to the faulty main water supply valve based on the predicted opening determined when the faulty main water supply valve is currently in a steady state; if the evaporator water level does not reach the preset water level within a preset time after adjustment, the evaporator water level corresponding to the faulty main water supply valve is adjusted based on the predicted opening determined when the faulty main water supply valve is currently not in a steady state.

[0119] Each module in the main water supply valve opening prediction device 60 can be implemented in whole or in part through software, hardware, or a combination thereof. Each module can be embedded in or independent of a processor in a computer device in the form of hardware, or can be stored in a memory in the computer device in the form of software, so that the processor can call and execute the corresponding operations of each module.

[0120] In an exemplary embodiment, an evaporator water level control system is provided, comprising a memory and a processor, wherein the memory stores a computer program, and when the processor executes the computer program, the method for predicting the opening of the main water supply valve provided in any of the above embodiments is implemented.

[0121] In one embodiment, a computer-readable storage medium is provided, on which a computer program is stored. When the computer program is executed by a processor, the method for predicting the opening of the main water supply valve provided in any of the above embodiments is implemented.

[0122] In one embodiment, a computer program product is provided, comprising a computer program, which, when executed by a processor, implements the main water supply valve opening prediction method provided in any of the above embodiments.

[0123] It should be noted that the user information (including but not limited to user device information, user personal information, etc.) and data (including but not limited to data used for analysis, stored data, displayed data, etc.) involved in this application are all information and data authorized by the user or fully authorized by all parties, and the collection, use and processing of relevant data must comply with relevant regulations.

[0124] Those skilled in the art will appreciate that all or part of the processes in the above-mentioned embodiments can be implemented by instructing the relevant hardware through a computer program. The computer program can be stored in a non-volatile computer-readable storage medium. When the computer program is executed, it can include the processes of the above-mentioned embodiments. In particular, any reference to a memory, database, or other medium used in the embodiments provided in this application can include at least one of a non-volatile memory and a volatile memory. Non-volatile memory can include read-only memory (ROM), magnetic tape, floppy disk, flash memory, optical memory, high-density embedded non-volatile memory, resistive random access memory (ReRAM), magnetic random access memory (MRAM), ferroelectric random access memory (FRAM), phase change memory (PCM), graphene memory, etc. Volatile memory can include random access memory (RAM) or external cache memory, etc. By way of illustration and not limitation, RAM can take various forms, such as static random access memory (SRAM) or dynamic random access memory (DRAM). The databases involved in the various embodiments provided herein may include at least one of a relational database and a non-relational database. Non-relational databases may include, but are not limited to, blockchain-based distributed databases. The processors involved in the various embodiments provided herein may be, but are not limited to, general-purpose processors, central processing units (CPUs), graphics processing units (GPUs), digital signal processors (DSPs), programmable logic devices (PLDs), quantum computing-based data processing logic devices, artificial intelligence (AI) processors, and the like.

[0125] The technical features of the above embodiments can be combined arbitrarily. In order to make the description concise, not all possible combinations of the technical features in the above embodiments are described. However, as long as there is no contradiction in the combination of these technical features, they should be considered to be within the scope of this application.

[0126] The above embodiments merely illustrate several implementation methods of the present application. While the descriptions are relatively specific and detailed, they should not be construed as limiting the scope of the present application. It should be noted that a person skilled in the art may make various modifications and improvements without departing from the spirit of the present application, all of which fall within the scope of protection of the present application. Therefore, the scope of protection of the present application shall be determined by the appended claims.

Claims

1. A method for predicting the opening of a main water supply valve, characterized in that: Applied to an evaporator water level control system, the method includes: In the event that a faulty main water supply valve is detected, the current state of the faulty main water supply valve is determined based on the difference between the water level of each evaporator and the evaporator water level set value and the water level change rate of the non-faulty evaporator; When the current state of the faulty main water supply valve is steady, the average value of the opening of the non-faulty main water supply valve is obtained and used as the predicted opening of the faulty main water supply valve; When the current state of the faulty main water supply valve is not steady state, the predicted opening of the faulty main water supply valve is determined based on the functional relationship between the main water supply valve cross-sectional area and the predicted opening of the main water supply valve and the main water supply valve cross-sectional area of ​​the faulty main water supply valve.

2. The method according to claim 1, characterized in that The process of determining the cross-sectional area of ​​the main water supply valve includes: Determine the main water supply flow rate based on the pressure difference before and after the main water supply valve; wherein the pressure difference before and after the main water supply valve refers to the difference between the water inlet pressure before the main water supply valve fails and the water inlet pressure after the failure, or the difference between the water outlet pressure before and after the main water supply valve fails; The cross-sectional area of ​​the main water supply valve is determined according to the functional relationship among the main water supply flow rate and the main water supply flow velocity, the main water supply flow rate and the main water supply flow velocity.

3. The method according to claim 2, characterized in that The process of determining the pressure difference before and after the main water supply valve includes: Obtain the potential difference between the feedwater pump outlet and the steam generator feedwater inlet; Obtain the pressure difference between the water main and the steam main; Based on the mapping relationship between the secondary circuit load and the pressure difference, a first pressure drop on the secondary side of the steam generator and a second pressure drop in the steam pipeline and / or the feedwater pipeline are obtained by fitting; The pressure difference before and after the main feedwater valve is determined based on the pressure difference between the feedwater main pipe and the steam main pipe, the potential difference between the feedwater pump outlet and the steam generator feedwater inlet, the first pressure drop and the second pressure drop.

4. The method according to claim 2, characterized in that Determining the main water supply flow rate according to the pressure difference before and after the main water supply valve includes: Obtain the product value of the preset constant, the pressure difference before and after the main water supply valve, and the acceleration of gravity; Obtaining the square root of the product value; The product value between the flow coefficient and the square root value is obtained and used as the main feed water flow rate.

5. The method according to any one of claims 1 to 4, characterized in that The process of determining whether the current state of the faulty main water supply valve is stable includes: When at least one of the following conditions is met, the current state of the faulty main water supply valve is determined to be steady state; the following conditions include that the water level change rate of the non-faulty evaporator is not greater than the standard value of the water level change rate of the non-faulty evaporator, and the absolute value of the difference between the water level of each evaporator and the evaporator water level set value is not greater than the standard value of the non-faulty evaporator water level deviation.

6. The method according to any one of claims 1 to 4, characterized in that The method further comprises: Adjust the evaporator water level corresponding to the faulty main water supply valve according to the predicted opening determined when the current state of the faulty main water supply valve is steady state; If the evaporator water level does not reach the preset water level within the preset time after adjustment, the evaporator water level corresponding to the faulty main water supply valve is adjusted according to the predicted opening determined when the current state of the faulty main water supply valve is not steady state.

7. A main water supply valve opening prediction device, characterized in that: Applied to the evaporator water level control system, the device includes: a state determination module for determining the current state of the faulty main water supply valve based on the difference between the water level of each evaporator and the evaporator water level set value and the water level change rate of the non-faulty evaporator when a faulty main water supply valve is detected; An opening prediction module is used to use the average opening of the main water supply valve of the non-faulty evaporator as the predicted opening of the faulty main water supply valve when the current state of the faulty main water supply valve is steady; The opening prediction module is also used to determine the predicted opening of the faulty main water supply valve based on the functional relationship between the main water supply valve cross-sectional area and the predicted opening of the main water supply valve and the main water supply valve cross-sectional area of ​​the faulty main water supply valve when the current state of the faulty main water supply valve is not steady state.

8. An evaporator water level control system, comprising a memory and a processor, wherein the memory stores a computer program, characterized in that: When the processor executes the computer program, the steps of the method according to any one of claims 1 to 6 are implemented.

9. A computer-readable storage medium having a computer program stored thereon, characterized in that: When the computer program is executed by a processor, the steps of the method according to any one of claims 1 to 6 are implemented.

10. A computer program product comprising a computer program, characterized in that When the computer program is executed by a processor, the steps of the method according to any one of claims 1 to 6 are implemented.

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