A closed-loop control method for a water pump and valve interlocking water filling system

Abstract

This invention discloses a closed-loop control method applicable to a pump-valve integrated water filling system. It includes the following steps: setting initial parameters for the pump-valve integrated water filling system; obtaining basic parameters for the pump-valve integrated water filling system; setting initial boundary conditions for the pump-valve integrated water filling system; and calculating, based on the initial parameters, basic parameters, and initial boundary conditions, the flow control valve opening curve, the water level change curve of the water being filled, the flow rate change curve of the pump-valve integrated water filling system, and the motion trajectory of the pump's operating point during the water filling process for closed-loop control of the pump-valve integrated water filling system. This invention enables better matching of the pump and valves in the pump-valve integrated water filling system, allowing for safe, stable, efficient, and rapid water filling of the water being filled.

Description

Technical Field

[0001] This invention belongs to the field of water conservancy and hydropower engineering technology, specifically relating to a closed-loop control method suitable for a water pump valve joint control water filling system. Background Technology

[0002] When filling reservoirs or large water tanks, filling long-distance water transmission pipelines, or filling the main pumping pipe before the initial start-up of large pumping stations, water pumps are required for filling. As the water level of the water-filled object changes during the filling process, the flow rate and head of the water pump will change: (1) In the early stage of filling, the water level of the water-filled object is low, the water pump has a large water flow rate and a low head. On the one hand, the cavitation performance of the water pump deteriorates, generating vibration and noise, which threatens the safe operation of the filling system. On the other hand, the excessive water flow rate has an adverse effect on the water-filled object: it threatens the safety of the reservoir slope, causes long-distance water transmission pipelines and poor air venting, which induces pipe bursts, and affects the turbulent flow in the main pumping pipe of large pumping stations, generating vortices. (2) In the later stage of filling, the water level of the water-filled object is high, the water pump has a small water flow rate and a high head. On the one hand, the water pump may enter the hump area and be difficult to operate stably. On the other hand, the water flow rate of the water-filled object is too small, resulting in a long filling time, which is not conducive to operation scheduling and management.

[0003] To ensure safe, stable, efficient, and rapid water filling, the engineering community favors pump-valve integrated water filling systems, which involve installing a flow regulating valve at the pump outlet. While this approach can mitigate the aforementioned issues through combined valve and pump control during the filling process, the water filling system is a temporary measure with extremely low usage frequency and receives little attention. For a long time, there has been a lack of an effective, scientific, efficient, and guiding system control method. In practice, it is difficult to achieve proper matching between the pump and valve, often requiring extensive debugging and testing. This not only fails to fully resolve issues related to the stability, safety, and speed of the water filling system but also significantly increases the workload for on-site maintenance units, wastes substantial human resources, and severely limits the functionality of pump-valve integrated water filling systems. Summary of the Invention

[0004] The purpose of this invention is to overcome the shortcomings of the aforementioned background technology and provide a closed-loop control method suitable for a water pump valve linkage water filling system.

[0005] The technical solution adopted in this invention is: a closed-loop control method for a water pump valve joint control water filling system, wherein the water pump valve joint control water filling system includes an inlet pool, a water pump and a water filling object connected in sequence, and a flow regulating valve provided on the pipeline system between the water pump and the water filling object;

[0006] Water level measuring element, used to measure the water level of a water-filled object;

[0007] Flow measurement elements are used to measure the flow rate in a piping system;

[0008] Feedback elements are used to control the start and stop of the water pump or to adjust the opening of the flow regulating valve;

[0009] The closed-loop control method applicable to the water pump valve linkage water filling system includes the following steps:

[0010] S1: Set the initial parameters of the water pump valve linkage water filling system;

[0011] S2: Obtain the basic parameters of the water pump valve linkage control water filling system. The basic parameters include the water pump characteristic curve, the flow control valve flow resistance opening curve, the pipeline characteristic curve, the water level change law of the water filling object, the flow control requirements of the water filling object, and the water level control requirements of the water filling object.

[0012] S3: Set the initial boundary conditions for the water pump and valve interlocking water filling system;

[0013] S4: Based on the initial parameters, basic parameters, and initial boundary conditions of the water pump and valve joint control water filling system, calculate the flow regulating valve opening action curve, the water level change curve of the water filling object, the flow rate change curve of the water pump and valve joint control water filling system, and the motion trajectory of the water pump working point during the water filling process for the closed-loop control of the water pump and valve joint control water filling system.

[0014] In step S1 above, the initial parameters include:

[0015] Q—Flow rate of water pumps and pipelines;

[0016] H—Pump head;

[0017] ξ—Flow resistance coefficient of the flow control valve;

[0018] α—Opening degree of the flow control valve;

[0019] z—Water level of the object being filled;

[0020] Z0—Initial water level in the forebay;

[0021] S—Horizontal cross-sectional area of ​​the water-filled object;

[0022] h—hydraulic loss in the water transmission network;

[0023] λ—hydraulic loss coefficient of water transmission network;

[0024] Q * —The object being filled with water and the control flow rate of the water filling system;

[0025] V * —Control the flow rate of water filling the object;

[0026] Z* —Target water level for the object being filled;

[0027] i—time period number, i = 0, 1, 2, 3, 4...;

[0028] △τ—Calculation time step;

[0029] t — time;

[0030] T y —The time it takes for the flow control valve to fully open or fully close;

[0031] Q i —The flow rate of the water pump and pipeline at time i;

[0032] H i —The pump head at time i;

[0033] ξ i —The flow resistance coefficient of the flow control valve at time i;

[0034] α i —The opening degree of the flow control valve at time i;

[0035] z i —The water level of the object being filled at time i;

[0036] S i —The horizontal cross-sectional area of ​​the water-filled object at time i;

[0037] h i —Hydraulic losses in the water supply network at time i;

[0038] t i —The time at time i;

[0039] ε—The allowable deviation range of the control flow rate of the water filling object and the water filling system;

[0040] ε * —The control flow alarm deviation range for the water filling object and the water filling system.

[0041] In step S2 above,

[0042] The formula for calculating the pump characteristic curve is: H = f(Q);

[0043] The formula for calculating the flow resistance opening curve of a flow control valve is: ξ=ξ(α);

[0044] The formula for calculating the characteristic curve of a pipeline network is: h = λ·Q 2 +(z-Z0);

[0045] The formula for calculating the water level change pattern of a water-filled object is: S = S(z);

[0046] The formula for calculating the flow control requirements of a water-filled object is: Q≤Q * And Q * =S×V * ;

[0047] The formula for calculating the water level control requirements of the object being filled with water is: z≤Z * .

[0048] In step S3 above, the initial boundary conditions include:

[0049] Assume T y Similar to Δτ, the impact of the flow control valve's operation on the water filling system during each time period needs to be considered;

[0050] At the initial time (i = 0), t = 0s, z0 = Z0, S0 = S(z0), α0 = e -5 .

[0051] In step S4 above, the process of calculating the flow control valve opening action curve, the water level change curve of the water-filled object, the flow rate change curve of the water pump valve control water filling system, and the motion trajectory of the water pump operating point during the water filling process includes:

[0052] In any time interval i, the following equations are solved simultaneously:

[0053] Q * i =S i ×V * ,

[0054] ξ i =ξ(α) i ),

[0055] h i =λ·Q i 2 +(z i -Z0),

[0056] f(Q i ) = h i +ξ i Q i 2 ,

[0057] Q i =Q * i ,

[0058] t i =i△τ,

[0059] Solving for ξ, we get i Q i H i , zi S i h i , t i ;

[0060] Equation iteration and its criterion conditions:

[0061] At the end of any i-th time period, the water level of the water-filled object is z. i+1 =z i +Q i △τ / S i ;

[0062] If z i+1 ≥Z * If the result is not found, the calculation ends and the result is output.

[0063] If z i+1 <Z * The calculated Q i The control flow rate Q of the water filling object and the water filling system * Comparison:

[0064] If Q * (1-ε)≤Q i ≤Q * (1+ε), then in the next stage α i+1 =α i ;

[0065] If Q i <Q * (1-ε), then in the next stage α i+1 =α i +△τ / T y ;

[0066] If Q * (1+ε)<Q i <Q * (1+ε * ), then in the next stage α i+1 =α i -△τ / T y ;

[0067] If Q i ≥Q * (1+ε * If the calculation is completed, the result will be output, an alarm signal will be issued, and the water pump will stop running.

[0068] Moving on to the next time interval (i+1), t i+1 =t i +△τ.

[0069] In step S4 above, the calculation results include:

[0070] The opening action curve of the flow control valve: α=α(t);

[0071] Water level change curve of the object being filled with water: z = z(t);

[0072] Flow rate variation curve of water pump and valve interlocking water filling system: Q = Q(t);

[0073] The trajectory of the pump's operating point: f(Q,H,i).

[0074] The present invention provides an initial opening degree for the flow regulating valve. During the water filling process, as the water level of the water filling object continuously rises, the operating point of the water pump continuously changes. By monitoring the control parameters during the water filling process in real time and comparing them with the control values, the comparison results are fed back to the electric actuator of the flow regulating valve to adjust the opening degree of the flow regulating valve, ultimately achieving closed-loop control of the water pump and valve joint control water filling system.

[0075] This invention is applicable to filling reservoirs or large water tanks with water, filling long-distance water transmission pipelines with water, and filling the main water supply pipe of large pumping stations with water before the initial start-up of pumps. It can be widely used in the field of water conservancy and hydropower engineering technology.

[0076] The beneficial effects of this invention are:

[0077] (1) The present invention enables the water pump and valve of the water pump valve joint control water filling system to be well matched, and to fill the water object safely, stably, efficiently and quickly.

[0078] (2) This invention can be used to guide the water filling of the object at the construction site. It is highly operable and automated, which greatly reduces the difficulty of on-site debugging and testing, improves the work efficiency of the operation and maintenance unit, and saves human resources costs.

[0079] (3) This invention can simulate in advance the movement trajectory of various control parameters during the water filling process, such as the working point of the water pump, the valve opening, the water filling flow rate of the pipeline network, and the water level of the water filling object. It can comprehensively analyze and evaluate the effect of the water filling system and provide a reference for the selection and optimization design of the water pump, valve, and pipeline system of the water pump and valve joint control water filling system. Attached Figure Description

[0080] Figure 1 This is a schematic diagram of the water pump valve linkage control water filling system to which this invention applies;

[0081] Figure 2 This is a logic diagram of a closed-loop control method for a water pump and valve interlocking water filling system according to the present invention.

[0082] In the diagram, 1-inlet pool, 2-water pump, 3-filling object, 4-piping system, 5-flow regulating valve, 6-water level measuring element, 7-flow measuring element, and 8-feedback element. Detailed Implementation

[0083] The present invention will be further described in detail below with reference to the accompanying drawings and specific embodiments to facilitate a clear understanding of the present invention, but these descriptions do not constitute a limitation on the present invention.

[0084] See Figure 1 The closed-loop control method of the water pump valve joint control water filling system applicable to this invention includes a water inlet pool 1, a water pump 2 and a water filling object 3 connected in sequence, and a flow regulating valve 5 on the pipeline system 4 between the water pump 2 and the water filling object 3.

[0085] Also includes:

[0086] Water level measuring element 6 is used to measure the water level of the water-filled object 3;

[0087] Flow measuring element 7 is used to measure the flow rate on the pipeline system 4;

[0088] Feedback element 8 is used to control the start and stop of water pump 2 or to adjust the opening of flow regulating valve 5.

[0089] See Figure 2 The present invention provides a logic diagram for a closed-loop control method applicable to a water pump and valve interlocking water filling system. The specific implementation steps of the present invention are as follows:

[0090] (1) Initial parameter definition

[0091] Q—Flow rate of water pumps and pipelines;

[0092] H—Pump head;

[0093] ξ—Flow resistance coefficient of the flow control valve;

[0094] α—Opening degree of the flow control valve;

[0095] z—Water level of the object being filled;

[0096] Z0—Initial water level in the forebay;

[0097] S—Horizontal cross-sectional area of ​​the water-filled object;

[0098] h—hydraulic loss in the water transmission network;

[0099] λ—hydraulic loss coefficient of water transmission network;

[0100] Q * —The object being filled with water and the control flow rate of the water filling system;

[0101] V * —Control the flow rate of water filling the object;

[0102] Z * —Target water level for the object being filled;

[0103] i—time period number, i = 0, 1, 2, 3, 4...;

[0104] △τ—Calculation time step;

[0105] t — time;

[0106] T y —The time it takes for the flow control valve to fully open or fully close;

[0107] Q i —The flow rate of the water pump and pipeline at time i;

[0108] H i —The pump head at time i;

[0109] ξ i —The flow resistance coefficient of the flow control valve at time i;

[0110] α i —The opening degree of the flow control valve at time i;

[0111] z i —The water level of the object being filled at time i;

[0112] S i —The horizontal cross-sectional area of ​​the water-filled object at time i;

[0113] h i —Hydraulic losses in the water supply network at time i;

[0114] t i —The time at time i;

[0115] ε—The allowable deviation range of the control flow rate of the water filling object and the water filling system;

[0116] ε * —The control flow alarm deviation range for the water filling object and the water filling system.

[0117] (2) Collect and organize the basic parameters of the water pump valve linkage water filling system as follows:

[0118] ① Pump characteristic curve H=f(Q);

[0119] ②Flow resistance opening curve of the flow control valve ξ=ξ(α);

[0120] ③ Pipeline characteristic curve h=λ·Q 2 +(z-Z0);

[0121] ④ The water level change pattern of the water-filled object is S = S(z);

[0122] ⑤ The flow control requirement for the water-filled object is Q≤Q * And Q *=S×V * ;

[0123] ⑥ The water level control requirement for the water-filled object is z≤Z * .

[0124] (3) Initial boundary conditions

[0125] Assume T y Similar to Δτ, the impact of the flow control valve's operation on the water filling system during each time period needs to be considered;

[0126] At the initial time (i = 0), t = 0s, z0 = Z0, S0 = S(z0), α0 = e -5 .

[0127] (4) Solving the simultaneous equations of the basic equations

[0128] In any time interval i, the following equations are solved simultaneously:

[0129] Q * i =S i ×V * ,

[0130] ξ i =ξ(α) i ),

[0131] h i =λ·Q i 2 +(z i -Z0),

[0132] f(Q i ) = h i +ξ i Q i 2 ,

[0133] Q i =Q * i ,

[0134] t i =i△τ,

[0135] Solving for ξ, we get i Q i H i , z i S i h i , t i .

[0136] (5) Iterative Equations and Their Criterion Conditions

[0137] At the end of any i-th time period, the water level of the water-filled object is z. i+1 =z i +Q i △τ / S i ;

[0138] If z i+1 ≥Z * If the result is not found, the calculation ends and the result is output.

[0139] If z i+1 <Z * The calculated Q i The control flow rate Q of the water filling object and the water filling system * The comparison yields the following four scenarios:

[0140] ①If Q * (1-ε)≤Q i ≤Q * (1+ε), then in the next stage α i+1 =α i ;

[0141] ②If Q i <Q * (1-ε), then in the next stage α i+1 =α i +△τ / T y ;

[0142] ③If Q * (1+ε)<Q i <Q * (1+ε * ), then in the next stage α i+1 =α i -△τ / T y ;

[0143] ④If Q i ≥Q * (1+ε * If the calculation is completed, the result will be output, an alarm signal will be issued, and the water pump will stop running.

[0144] Moving on to the next time interval (i+1), t i+1 =t i +△τ.

[0145] (6) Output of Results

[0146] The following results can be obtained from the above calculations:

[0147] ① Flow control valve opening action curve: α=α(t);

[0148] ② Water level change curve of the object being filled with water: z = z(t);

[0149] ③ Flow rate change curve of the water pump and valve interlocking water filling system: Q = Q(t);

[0150] ④ The trajectory of the pump's working point: f(Q,H,i).

[0151] (7) Simulation and analysis of water filling process

[0152] Based on the parameters obtained from the above calculations, the water filling process of the pump-valve interlocking system can be simulated, and the technical and economic indicators of the changes in each parameter can be analyzed:

[0153] ①Based on the flow control valve opening action curve obtained from the calculation simulation, analyze whether the flow control valve opening is within a reasonable range, and whether adverse effects such as cavitation will occur during the valve action. Provide reasonable suggestions for the selection and design of the flow control valve in the water pump valve joint control system, and correct the full opening or full closing action time of the flow control valve.

[0154] ②Based on the water level change curve of the water-filled object obtained from the calculation and simulation, analyze whether the water level change is reasonable, adjust the allowable deviation range of the control flow of the water-filled object and the water-filling system, as well as the alarm deviation range, to provide guidance for the operation and management of the water-filled object;

[0155] ③Based on the flow change curve of the pump-valve interlocking water filling system obtained from the calculation simulation, analyze whether the flow change range of the pipeline network is reasonable, and provide reasonable suggestions for the pipeline network design of the pump-valve interlocking system;

[0156] ④ Based on the motion trajectory of the pump's operating point obtained from the calculation simulation, analyze whether the pump can operate safely and efficiently during the water filling process, and provide reasonable suggestions for the pump selection and design of the pump valve linkage system.

[0157] (8) Proposal of a closed-loop control method for a water pump and valve joint control system

[0158] Based on the calculations and analyses in steps (1) to (7) above, a closed-loop control method for the water pump valve linkage control system is proposed, including: the action time of the flow regulating valve being fully open or fully closed, the water filling object, the allowable deviation range of the control flow of the water filling system, the alarm deviation range, and relevant suggestions for the water pump valve linkage control water filling system.

[0159] The contents not described in detail in this specification are existing technologies known to those skilled in the art.

Claims

1. A closed-loop control method for a water pump valve-controlled water filling system, characterized in that: The water pump and valve control water filling system includes an inlet pool, a water pump and a water filling object connected in sequence, as well as a flow regulating valve on the pipeline system between the water pump and the water filling object; Water level measuring element, used to measure the water level of a water-filled object; Flow measurement elements are used to measure the flow rate in a piping system; Feedback elements are used to control the start and stop of the water pump or to adjust the opening of the flow regulating valve; The closed-loop control method applicable to the water pump valve linkage water filling system includes the following steps: S1: Set the initial parameters of the water pump valve linkage water filling system; S2: Obtain the basic parameters of the water pump valve linkage control water filling system. The basic parameters include the water pump characteristic curve, the flow control valve flow resistance opening curve, the pipeline characteristic curve, the water level change law of the water filling object, the flow control requirements of the water filling object, and the water level control requirements of the water filling object. S3: Set the initial boundary conditions for the water pump and valve interlocking water filling system; S4: Based on the initial parameters, basic parameters, and initial boundary conditions of the water pump valve joint control water filling system, calculate the flow regulating valve opening action curve, the water level change curve of the water filling object, the flow rate change curve of the water pump valve joint control water filling system, and the motion trajectory of the water pump working point during the water filling process for the closed-loop control of the water pump valve joint control water filling system. In step S2 above, The formula for calculating the pump characteristic curve is: H = f(Q); The formula for calculating the flow resistance opening curve of a flow control valve is: ξ=ξ(α); The calculation formula of the pipe network characteristic curve: h = λ • Q 2 + (z - Z0); The formula for calculating the water level change pattern of a water-filled object is: S=S(z); The formula for calculating the flow control requirements of the water-filled object is: Q≤Q*, and Q*=S×V*; The formula for calculating the water level control requirements of the object being filled with water is: z≤Z*; In step S4 above, the process of calculating the flow control valve opening action curve, the water level change curve of the water-filled object, the flow rate change curve of the water pump valve control water filling system, and the motion trajectory of the water pump operating point during the water filling process includes: In any time interval i, the following equations are solved simultaneously: Q * i =S i ×V * , ξ i =ξ(α i ), h i = λ • Q i 2 + (z i - Z0), f(Q i )= h i +ξ i Q i 2 , Q i =Q * i , t i =i△τ, Solving for ξ, we get i Q i H i , z i S i h i , t i ; Equation iteration and its criterion conditions: At the end of any i-th time period, the water level of the water-filled object is z. i+1 = z i + Q i △τ / S i ; If z i+1 ≥Z * If the result is not found, the calculation ends and the result is output. If z i+1 <Z * The calculated Q i The control flow rate Q of the water filling object and the water filling system * Comparison: If Q * (1-ε)≤Q i ≤Q * (1+ε), then in the next stage α i+1 =α i ; If Q i <Q * (1-ε), then in the next stage α i+1 =α i +△τ / T y ; If Q * (1+ε) < Q i <Q * (1+ε * ), then in the next stage α i+1 =α i -△τ / T y ; If Q i ≥Q * (1+ε * If the calculation is completed, the result will be output, an alarm signal will be issued, and the water pump will stop running. Moving on to the next time interval (i+1), t i+1 = t i +△τ; In step S4 above, the calculation results include: The opening action curve of the flow control valve is: α = α(t); Water level change curve of the filled object: z=z(t); Flow rate variation curve of water pump and valve interlocking water filling system: Q=Q(t); The trajectory of the pump's operating point: f(Q,H,i); in, Q—Flow rate of water pumps and pipelines; H—Pump head; ξ—Flow resistance coefficient of the flow control valve; α—Opening degree of the flow control valve; z—Water level of the object being filled; Z0—Initial water level in the forebay; S—Horizontal cross-sectional area of ​​the water-filled object; h—hydraulic loss in the water supply network; λ—hydraulic loss coefficient of water transmission network; Q * —The object being filled with water and the control flow rate of the water filling system; V * —Control the flow rate of water filling the object; Z * —Target water level for the object being filled; i—time period number, i=0,1,2,3,4……; △τ—Calculation time step; t — time; T y —The time it takes for the flow control valve to fully open or fully close; Q i —The flow rate of the water pump and pipeline at time i; H i —The pump head at time i; ξ i —The flow resistance coefficient of the flow control valve at time i; α i —The opening degree of the flow control valve at time i; z i —The water level of the object being filled at time i; S i —The horizontal cross-sectional area of ​​the water-filled object at time i; h i —Hydraulic losses in the water supply network at time i; t i —The time at time i; ε—The allowable deviation range of the control flow rate of the water filling object and the water filling system; ε * —The control flow alarm deviation range for the water filling object and the water filling system.

2. The closed-loop control method for a water pump valve interlocking water filling system according to claim 1, characterized in that: In step S3 above, the initial boundary conditions include: Assume T y Similar to Δτ, the impact of the flow control valve's operation on the water filling system during each time period needs to be considered; At the initial time i=0, t=0s, z0=Z0, S0=S(z0), α0=e -5 .

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