Power plant chemical water system and sequence control strategy optimization method based on programming language

Abstract

The present application relates to a kind of power plant chemical water system and sequential control strategy optimization method based on programming language, the technical field of power plant chemical water treatment control, the method includes: in DCS controller deployment CALC function block, reconstruct traditional sequential control logic by structured programming language;Three-layer architecture including basic layer, state judgment layer and program-controlled execution layer is constructed;System operating parameters and equipment status are collectively processed using conditional judgment expression, replacing the dispersed logic module in traditional ladder diagram, state transition, multi-condition decision, safety interlocking and adaptive step control are realized.The problems of existing chemical water treatment control logic, high controller load, poor maintenance and expansion are effectively solved, centralized management and simplification of control logic are realized, the controller load rate is significantly reduced, the system response speed and operation reliability are improved, and it is suitable for optimization and modification of various power plant chemical water treatment systems.

Description

Technical Field

[0001] This invention relates to the field of power plant chemical water treatment control technology, specifically to a power plant chemical water system and a sequential control strategy optimization method based on a programming language. Background Technology

[0002] The chemical water treatment system in a power plant is a critical auxiliary system ensuring the safe and stable operation of generator units. The reliability of its control system directly impacts the overall plant's production safety and efficiency. Currently, the sequential control logic of most power plant chemical water treatment systems still relies on traditional modular programming languages ​​(such as ladder diagrams (LD) and function block diagrams (FBD)). While these methods are intuitive and easy to understand, they have significant drawbacks when dealing with control systems with complex processes and numerous interlocking conditions, such as ultrafiltration and reverse osmosis. 1. Bulky and Complex Logic: Complex sequential control relies on a large number of AND, OR, and NOT logic modules, timers, and intermediate variables. This results in a large number of control logic diagrams, long signal transmission links, high system complexity, and an increase in potential points of failure.

[0003] Second, high controller load: Distributed and complex logic operations consume a large amount of the DCS controller's memory and CPU resources. During the logic scan cycle, the controller operates under high load for extended periods, which can easily cause system response delays and even affect the overall stability of the system.

[0004] Third, poor maintainability and scalability: Traditional logic configurations are often scattered across multiple sub-modules or pages, lacking a unified state management entry point. When the process flow is adjusted or equipment is updated, technicians need to modify a large number of logic connections across pages, resulting in a large workload for configuration modifications, a long debugging cycle, and an easy introduction of human error. Summary of the Invention

[0005] This invention addresses the shortcomings of existing technologies by providing a programming language-based optimization method for power plant chemical water systems and sequential control strategies. It effectively solves the problems of bloated control logic, high controller load, and poor maintenance and scalability in existing chemical water treatment systems. It achieves centralized management and simplification of control logic, significantly reduces controller load, and improves system response speed and operational reliability. It is applicable to the optimization and transformation of various power plant chemical water treatment systems.

[0006] The above-mentioned technical problems of the present invention are mainly solved by the following technical solutions: A method for optimizing the control strategy of a power plant chemical water treatment system based on a programming language is characterized by the following steps: deploying CALC function blocks to the DCS controller, and reconstructing the traditional sequential control logic using a structured programming language, specifically including the following: Basic layer configuration: Retain the manual operation block and timing block, and provide a manual operation interface and basic timing function for the device.

[0007] Status Judgment Layer: The CALC function block centrally collects system operating parameters and equipment status signals, and outputs unified control sequence instructions through logical operations.

[0008] Programmable execution layer: Receives the control sequence instructions through the CALC function block, maps them into equipment-level operation instructions through internal programming logic, and controls the start-up, shutdown, and adjustment of valves, water pumps, and dosing equipment.

[0009] The system operating parameters include one or more of the following: inlet water pressure, product water flow rate, turbidity, SDI value, and number of product water cycles.

[0010] Preferably, the logical operations of the state judgment layer are implemented using conditional judgment expressions, including: State transition logic: if(A=1&B,2,A), where A is the current step number and B is the timing signal. When the water production condition is met and the timing is satisfied, the backwash waiting step is output; otherwise, the original state is maintained.

[0011] Multi-condition decision logic: if(A=2&B&C&(D<50orE),3,Y1), where A is the current step sequence number, B is the timeout signal, C is the non-backwash state signal, D is the number of water productions, and E is the preset trigger condition. When the backwash waiting state, timeout, non-backwash and water production count is less than 50, or condition E is met, the normal backwash step sequence is output.

[0012] As a preferred option, it also includes safety interlock logic: if(A=2&B&D>49&(notE)&F<2,4,Y2), where A is the current step number, B is the timer signal, D is the number of water production cycles, E is the shutdown flushing signal, and F is the chemical dosing backwashing flag. When the number of water production cycles is greater than 49 and the non-shutdown flushing and chemical dosing backwashing flags are less than 2, the HCl pre-addition backwashing step is triggered.

[0013] As a preferred option, it also includes adaptive stepping logic: if((A>3)&(A<15)&B&C,A+1,Y5), where A is the current step number, and B and C are preset working condition allow signals; when the backwashing stage is in step 3 to 15 and the working condition is allowed, it automatically steps to the next step.

[0014] Preferably, the method is applied to an ultrafiltration system, and the equipment-level operation commands include one or more of the following: inlet valve on / off control, product water valve adjustment, backwash pump start / stop, and dosing metering pump start / stop.

[0015] A control device for a power plant chemical water treatment system based on a programming language, characterized in that it comprises: The parameter acquisition module is used to collect operating parameters and equipment status feedback signals of the power plant's chemical water treatment system.

[0016] The DCS controller has a built-in CALC function block, which is configured to execute the control strategy optimization method for the power plant chemical water treatment system.

[0017] The device execution module, connected to the DCS controller, is used to receive device-level operation commands output by the CALC function block and control the operation of valves, pumps and dosing equipment in the chemical water treatment system.

[0018] Preferably, when the inlet water pressure exceeds the limit or the turbidity of the product water exceeds the standard, a safety shutdown command is automatically triggered, and an alarm signal is sent to the operation and maintenance terminal through the DCS controller.

[0019] Preferably, the computer program, when executed by the processor, implements a method for optimizing the control strategy of a power plant chemical water treatment system.

[0020] The present invention can achieve the following effects: This invention provides a method for optimizing the sequential control strategy of a power plant chemical water system based on a programming language, which has the following significant advantages compared with existing technologies: I. Logic Simplification and Clarity: By using CALC function blocks and a structured programming language, the originally scattered hardware logic modules are integrated into a centralized software logic expression, eliminating more than 80% of the intermediate variables and connections in traditional ladder diagrams. The control logic changes from a "hard-wired" module stacking to a "soft logic" conditional judgment, improving the clarity of the control flow by more than 60% and greatly reducing the difficulty of logic troubleshooting.

[0021] II. Significantly Improved System Performance: The optimized logical architecture significantly reduces the computational burden on the controller. Actual test data shows that the controller load rate decreased from 28.5% to 20.4% (a reduction of approximately 28.4%), the network load rate decreased from 15.4% to 14.2% (a reduction of approximately 7.8%), and the average system response time was shortened from 417ms to 391ms (a reduction of approximately 6.3%), effectively improving the system's real-time performance and operational efficiency.

[0022] III. Enhanced Safety and Reliability: Supports complex multi-condition judgments and safety interlock logic (such as water production cycle determination, chemical dosing backwash interlock, etc.), enabling more stringent fault protection strategies through programming. When parameter limits are exceeded or equipment malfunctions are detected, the system can quickly trigger a safety shutdown command, significantly improving automatic fault detection and alarm response speed.

[0023] V. Convenient maintenance and strong scalability: The core control logic is concentrated within the CALC function block, forming a unified "status judgment layer" and "programmable execution layer". When process parameters are adjusted or control strategies are changed, only the expression parameters within the function block need to be modified, without large-scale reconstruction of hardware configuration and wiring logic, which shortens the debugging cycle by more than 70% and significantly reduces operation and maintenance costs. Attached Figure Description

[0024] Figure 1 This is a schematic diagram of the chemical water treatment system of the present invention.

[0025] Figure 2 This is a flowchart of the conventional control logic framework of the present invention.

[0026] Figure 3 This is a flowchart of the optimized control logic framework of the present invention.

[0027] Figure 4 This is the ultrafiltration A-sequential control programming language annotation table of the present invention.

[0028] Figure 5 This is a bar chart comparing the performance of the present invention before and after optimization. Detailed Implementation

[0029] The technical solution of the invention will be further described in detail below through embodiments and in conjunction with the accompanying drawings.

[0030] Example 1: As Figure 1-4 As shown, a method for optimizing the control strategy of a power plant chemical water system based on a programming language is proposed. This method involves deploying CALC (Computer Algorithm) function blocks in the DCS controller and reconstructing the traditional ladder logic using a structured programming language. The specific implementation steps are as follows: I. Logical architecture restructuring. For example... Figure 3 As shown, the previously distributed control logic is integrated into the CALC function block to construct a three-layer control architecture: Basic layer configuration: Retain the original manual control block (for on-site manual operation interface) and timing block (providing basic timing function). This layer serves as the underlying support, ensuring that operators can still control field equipment through the DCS manual operation interface when automatic logic fails or equipment is under maintenance.

[0031] Status Judgment Layer: This layer centrally collects system operating parameters (such as inlet water pressure, product water flow rate, turbidity, SDI value, and product water frequency) and equipment status signals (such as valve feedback and pump operation feedback) through CALC function blocks. It uses structured text language to write logical expressions, replacing numerous intermediate relays and comparison blocks in traditional ladder diagrams, and outputs unified control sequence instructions after calculation.

[0032] Programmable Execution Layer: The CALC function block receives the step sequence instructions output from the status judgment layer and directly maps them into device-level operation instructions through internal programming logic. For example, when the "routine backwash" step sequence instruction is output, the CALC block directly drives the corresponding valve to open and the water pump to start, replacing the complex subroutine calls and output coil mapping in traditional logic.

[0033] II. Core Logic Programming Implementation. The control logic in the CALC function block is written using structured expressions similar to C language, specifically including: The state transition logic is implemented using the expression `if(A=1&B,2,A)`. Here, variable A is the current step number, and variable B is the timing signal. This logic means that when the system is in the water production step (A=1) and the water production timing has ended (B=1), the system outputs the step instruction "2" (backwash waiting step); otherwise, the system remains in its original state A.

[0034] Multi-condition decision logic: Implemented using the expression if(A=2&B&C&(D<50orE),3,Y1). Where A is the current step number, B is the timeout signal, C is the non-backwash state signal, D is the number of water production cycles, and E is the preset trigger condition (such as water quality deterioration signal). This logic means that when the system is in a backwash waiting state (A=2), timeout (B=1), or non-backwash state (C=1), and the number of water production cycles is less than 50 or the preset trigger condition E is met, the system outputs the step sequence instruction "3" (normal backwash step sequence); otherwise, it outputs Y1 to maintain the current state.

[0035] Safety interlock logic: Implemented using the expression if(A=2&B&D>49&(notE)&F<2,4,Y2). Here, E is the shutdown flushing signal, and F is the chemical dosing backwash flag. This logic means that when the number of permeate flows (D) is greater than 49, and the safety conditions of non-shutdown flushing and chemical dosing backwash flag being less than 2 are met, the system skips the regular backwash and directly triggers step "4" (the backwash step before adding HCl) to achieve targeted chemical cleaning and prevent membrane fouling.

[0036] Adaptive stepping logic: Implemented using the expression if((A>3)&(A<15)&B&C,A+1,Y5). This logic is used for automatic process control during the backwashing phase. When the current step A is in the backwashing phase (steps 3 to 15), and both the operating condition signals B and C are satisfied, the system automatically steps to the next step (A+1) without manual intervention, thus achieving automated flow of the backwashing process.

[0037] Example 2: A control device for implementing the above method, such as... Figure 1 As shown, the device includes: Parameter acquisition module: Composed of instruments such as pressure transmitters, flow meters, and turbidity meters installed on-site. This module is responsible for real-time acquisition of analog signals such as inlet water pressure, product water flow rate, turbidity, and SDI value, as well as digital signals such as valve open / close status and pump operating status, and transmitting them to the DCS controller.

[0038] DCS Controller: The NARI-MAXDNA distributed control system controller is selected, which internally deploys a CALC function block. This controller is configured to execute the control strategy optimization method described in Example 1. The CALC function block receives data uploaded by the parameter acquisition module, performs logical operations, and outputs control commands.

[0039] Equipment execution module: This module includes actuators such as inlet valve, product water valve, backwash pump, and dosing metering pump. It connects to the DCS controller output, receives equipment-level operation commands from the CALC function block, and executes corresponding valve opening / closing or pump start / stop actions.

[0040] In addition, the CALC function block is also configured with anomaly handling capabilities. When an inlet water pressure exceeding the limit (e.g., >0.3MPa) or a product water turbidity exceeding the standard is detected, the internal logic of the CALC block immediately triggers a safety shutdown command (e.g., forcibly closing the inlet water valve or stopping the high-pressure pump), and sends an audible and visual alarm signal to the operation and maintenance terminal through the DCS alarm system to ensure system safety.

[0041] Example 3: Figure 5 As shown, the application effect is verified.

[0042] Implementation Plan: The existing ladder logic-based PLC control logic is migrated to the maxDNA DCS system. The previously dispersed state judgment, timing control, and interlocking protection functions are encapsulated into three CALC function blocks: CALA01, CALA02, and CALA03. The original logic contained 12 AND / OR logic modules and 8 timers; after reconstruction, the same functionality can be achieved with just a few lines of IF-ELSE expressions.

[0043] Testing process: The system ran continuously for 76 hours, covering all operating conditions including water production, routine backwashing, enhanced chemical backwashing, and shutdown flushing. Simultaneously, safety interlock tests were conducted, simulating scenarios of exceeding the water production limit (D=51) and exceeding the inlet pressure limit (>0.3MPa).

[0044] Test Results: Functional Verification: All step sequence jumps were normal, and the equipment actions were accurate and error-free. When the simulated water production count D=51, the system automatically triggered the backwashing step before adding HCl; when the simulated inlet water pressure exceeded the limit, the system performed a safe shutdown within 0.5 seconds, meeting the design requirements.

[0045] Performance metrics comparison: The optimized system shows a significant improvement in all performance metrics.

[0046] In summary, this optimization method for power plant chemical water systems and sequential control strategies based on programming languages ​​effectively reduces the controller's computational load and network communication pressure by reconstructing the logic using structured programming languages, thereby improving the system's response speed and operational reliability, and achieving the expected optimization results.

[0047] The above description is only a specific embodiment of the present invention, but the structural features of the present invention are not limited thereto. Any changes or modifications made by those skilled in the art within the scope of the present invention are covered by the patent scope of the present invention.

Claims

1. A method for optimizing the control strategy of a power plant chemical water system based on a programming language, characterized in that, Includes the following steps: Deploy CALC function blocks to the DCS controller and reconstruct the traditional sequential control logic using a structured programming language, specifically including the following: Basic layer configuration: Retain the manual operation block and timing block, and provide a manual operation interface and basic timing function for the device; Status Judgment Layer: Collects system operating parameters and equipment status signals centrally through CALC function blocks, and outputs unified control sequence instructions after logical operations; Programmable execution layer: Receives the control sequence instructions through the CALC function block, maps them into device-level operation instructions through internal programming logic, and controls the start-up, shutdown, and adjustment of valves, water pumps, and dosing equipment; The system operating parameters include one or more of the following: inlet water pressure, product water flow rate, turbidity, SDI value, and number of product water cycles.

2. The method for optimizing the control strategy of a power plant chemical water system based on a programming language according to claim 1, characterized in that, The logical operations of the state judgment layer are implemented using conditional judgment expressions, including: State transition logic: if(A=1&B,2,A), where A is the current step number and B is the timing signal. When the water production condition is met and the timing is satisfied, output the backwash waiting step sequence; otherwise, maintain the original state. Multi-condition decision logic: if(A=2&B&C&(D<50orE),3,Y1), where A is the current step sequence number, B is the timeout signal, C is the non-backwash state signal, D is the number of water productions, and E is the preset trigger condition. When the backwash waiting state, timeout, non-backwash and water production count is less than 50, or condition E is met, the normal backwash step sequence is output.

3. The method for optimizing the control strategy of a power plant chemical water system based on a programming language according to claim 1, characterized in that, It also includes safety interlock logic: if(A=2&B&D>49&(notE)&F<2,4,Y2), where A is the current step number, B is the timer signal, D is the number of water production cycles, E is the shutdown flushing signal, and F is the chemical dosing backwashing flag. When the number of water production cycles is greater than 49 and the non-shutdown flushing and chemical dosing backwashing flags are less than 2, the HCl pre-addition backwashing step is triggered.

4. The method for optimizing the control strategy of a power plant chemical water system based on a programming language according to claim 1, characterized in that, It also includes adaptive stepping logic: if((A>3)&(A<15)&B&C,A+1,Y5), where A is the current step number, and B and C are preset working condition enable signals; when the backwashing stage is in step 3 to 15 and the working condition is enabled, it automatically steps to the next step.

5. The method for optimizing the control strategy of a power plant chemical water system based on a programming language according to claim 1, characterized in that, The method is applied to an ultrafiltration system, and the equipment-level operation commands include one or more of the following: inlet valve on / off control, product water valve adjustment, backwash pump start / stop, and dosing metering pump start / stop.

6. A control device for a power plant chemical water system based on a programming language, characterized in that, include: The parameter acquisition module is used to collect operating parameters and equipment status feedback signals of the power plant's chemical water treatment system. The DCS controller has a built-in CALC function block, which is configured to execute the power plant chemical water treatment system control strategy optimization method according to any one of claims 1 to 5. The device execution module, connected to the DCS controller, is used to receive device-level operation commands output by the CALC function block and control the operation of valves, pumps and dosing equipment in the chemical water treatment system.

7. The power plant chemical water system control device according to claim 6, characterized in that, The CALC function block is also configured to automatically trigger a safety shutdown command when the inlet water pressure exceeds the limit or the turbidity of the product water exceeds the standard, and send an alarm signal to the operation and maintenance terminal through the DCS controller.

8. A computer-readable storage medium having a computer program stored thereon, characterized in that, When the computer program is executed by the processor, it implements the power plant chemical water treatment system control strategy optimization method according to any one of claims 1 to 5.

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