JP2008052508A - Control system of water treatment plant - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a control system effectively suppressing occurrence of a water hammer or hunting by suitably controlling a flow rate control valve for controlling water supply, in a water treatment plant such as a water and sewer plant. <P>SOLUTION: The water and sewer plant is provided with the flow rate control valve 3 provided to a piping system 6 to control the flow rate of water supply and a controller 100 for controlling the open/close of the flow rate control valve 3 and controlling the opening/closing speed of the flow rate control valve 3 on the basis of the open/close pressure difference of the flow rate control valve 3. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to a control system for a water treatment plant such as a water and sewage plant.

  Conventionally, for example, in a water supply plant, a structure in which water is introduced from a reservoir serving as a water source to a distribution reservoir or the like through piping. The pipe is provided with a flow rate adjusting valve for opening and closing the valve according to the operation of the actuator and adjusting the flow rate of water flow.

  Here, for example, the reservoir is at a higher position in terms of civil engineering structure than the reservoir. As a result, the water is led from the reservoir to the reservoir by natural flow. At this time, a water hammer is generated in the flow control valve by the water pressure flowing through the pipe. Moreover, a state called so-called hunting is generated in which the opening and closing of the flow rate control valve is frequently repeated according to fluctuations in the water level of the reservoir.

Conventionally, a control method has been proposed in which a water hammer phenomenon generated in piping is suppressed by controlling an electric valve used in a water gun of a digestion facility (see, for example, Patent Document 1). Moreover, the control method which suppresses the hunting phenomenon which repeats the raise and fall of the water level of a reservoir is proposed (for example, refer patent document 2).
JP 2002-295705 A JP-A-9-138708

  In a water treatment plant such as a water and sewage plant, water flow is adjusted by opening and closing a flow control valve provided in a pipe. However, water hammer and hunting occur in the flow control valve due to fluctuations in water pressure and fluctuations in the water level in the reservoir. In order to suppress this water hammer and hunting, appropriate control of the flow control valve is required.

  An object of the present invention is to provide a control system capable of effectively suppressing the occurrence of water hammer and hunting by appropriately controlling a flow rate control valve for controlling water flow in a water treatment plant such as a water and sewage plant. It is in.

  A control system for a water treatment plant according to an aspect of the present invention is a water treatment plant that performs water treatment such as water purification on water from a water source, and distributes a reservoir for storing the water and pressurized water from the reservoir. A piping system for passing water to the water pond, a flow control valve provided in the piping system for adjusting the flow rate of the water flow, and opening / closing of the flow control valve to control the opening / closing pressure difference of the flow control valve. And a control means for controlling the opening / closing speed of the flow rate control valve.

  ADVANTAGE OF THE INVENTION According to this invention, generation | occurrence | production of a water hammer and a hunting can be effectively suppressed by controlling appropriately the flow control valve which controls water flow in water treatment plants, such as a water and sewage plant.

  Embodiments of the present invention will be described below with reference to the drawings.

[First Embodiment]
Hereinafter, a control system for a water treatment plant according to the first embodiment will be described with reference to FIGS. 1 to 6.

(Configuration of water treatment plant)
This embodiment demonstrates a waterworks plant as a water treatment plant. FIG. 1 is a diagram for explaining a water purification process of a waterworks plant.

  The water supply plant introduces raw water from, for example, the dam 1 or the river 30 as a water source (hereinafter sometimes referred to as a reservoir). The raw water from the reservoir 1 is led to the landing well 5 through the pipe 6. The pipe 6 is provided with a flow meter 2 and a flow control valve 3. The flow rate adjustment valve 3 is opened and closed by the operation of the actuator 4 to adjust the flow rate of water flow. In FIG. 1, “X” means various sensors such as a flow meter, and “M” means a driving unit such as an actuator or a motor.

  On the other hand, raw water from the river 30 is led to a sand basin 32 having an on-off valve 31. The sand basin 32 is provided with a screen 33, and the introduced raw water is filtered. Further, water is introduced from the pump well 34 to the landing well 5 by the water introduction pump 35. The pipe connecting the pump well 34 and the landing well 5 is provided with a flow control valve 36 and a flow meter 37.

  The water introduced to the landing well 5 is sent to the settling basin 11. A mixing basin 9 and a floc-forming basin 10 are arranged in the preceding stage of the settling basin 11. A flow meter 7 and a flow rate control valve 8 are provided in the pipe connecting the landing well 5 and the mixing basin 9.

  On the other hand, the return water from the settling basin 11 is introduced into the landing well 5. The return water from the settling basin 11 is sent to the sludge basin 39 after the flow rate is adjusted by the flow rate control valve 38. Further, the returned water is sent from the sludge basin 39 to the sewage basin 40 and returned from the sewage basin 40 to the receiving well 5 by the return pump 41. In the sludge pond 39, the sludge is dehydrated and disposed of. A flow rate adjusting valve 42 and a flow meter 43 are provided in the pipe connecting the landing well 5 and the sewage basin 40.

  Next, the water guided to the sedimentation basin 11 is filtered by the filtration basin 12 and then sent to the water purification basin 13. Flow pipes 50 and 52 and a flow meter 51 are provided on the pipe connecting the filtration basin 12 and the clean water basin 13. From the upper surface of the water introduced to the clean water basin 13, it is returned to the filtration basin 12 by the surface washing pump 46. Flow control valves 47 to 49 are provided in the piping connecting the surface washing pump 46 and the filtration basin 12.

  Further, in the water purification tank 13, a part of the water guided by the backflow pump 53 is returned to the filtration pond 12. A flow meter 54 and flow rate control valves 55 and 56 are provided on the pipe connecting the backflow pump 53 and the filtration basin 12. In the filtration basin 12, part of the introduced water is returned to the sewage basin 40 via the flow rate control valve 44. Further, a part of the water returned to the filter basin 12 by the backflow pump 53 is returned to the sewage basin 40 via the flow rate control valve 45.

  The water purified by the water purification tank 13 is sent to the distribution reservoir 16 via the pipe 23 by the water pump 20. The pipe 23 is provided with flow control valves 15 and 21 and a flow meter 22. The distribution reservoir 16 is provided with a water level meter 17 and a water quality sensor 18 for measuring the water level. The purified water from the distribution reservoir 16 is distributed by being controlled by the flow control valve 19. On the other hand, the water purified by the water purification tank 13 is distributed by the water distribution pump 24 via the pipe 27. The pipe 27 is provided with a flow control valve 25 and a flow meter 26.

  As such a water supply plant control system, a controller 100 having a computer as a main element is provided. The controller 100 inputs measurement signals from various sensor groups and detects the flow rate, water level, sludge amount, water quality, and the like, and controls the flow rate control valve and the pump.

(Control system)
FIG. 2 is a diagram showing a water introduction process in which raw water is introduced from the reservoir 1 serving as a water source to the landing well 5 in the above-described water supply plant. Taking this process as a specific example, the operation of the plant control system according to this embodiment will be described.

  As shown in FIG. 2, the water introduction process has a structure in which a pipe 6 is connected to the reservoir 1, and water from the reservoir 1 is introduced to the landing well 5 through the flow control valve 3. As shown in FIG. 1, the reservoir 1 has a higher civil engineering structure than the landing well 5. The water pressure from the reservoir 1 is larger than the water pressure of the landing well 5, and the water is introduced from the reservoir 1 to the landing well 5 by natural flow by opening the flow control valve 3.

  The flow control valve 3 is connected to an actuator 4 for changing the opening of the valve. The controller 100 outputs a command for controlling the operation of the actuator 4 and changes the opening degree of the flow control valve 3.

  FIG. 3 is a diagram showing the relationship between the valve opening degree of the flow rate control valve 3 and the time required for opening and closing. In FIG. 3, the characteristic indicated by reference numeral 300A indicates that the valve 3 is open in a shorter time than the characteristic indicated by reference numeral 300B. Here, the times until the valve 3 is fully opened are ta and tb, respectively. Further, the pressure applied to the valve 3 when the valve 3 is fully closed is Pc, and the pressure applied when the valve 3 is fully opened is Po.

  In the case of the characteristic of the reference numeral 300A, the pressure change Pa per hour generated in the flow rate control valve 3 is obtained from the relational expression “Pa = (Pc−Po) / ta”. Further, in the case of the characteristic of the reference numeral 300B, the pressure change Pb per time generated in the flow rate control valve 3 is obtained from the relational expression “Pb = (Pc−Po) / tb”.

  As apparent from the characteristics of FIG. 3, since the relationship of “ta <tb” is satisfied, the characteristic indicated by the reference numeral 300B, that is, when the flow rate adjusting valve 3 is opened and closed over a long time is generated in the valve 3. The pressure change per hour (Pb) is relatively small.

  By the way, the magnitude of the water hammer generated in the flow control valve 3 is proportional to the pressure change per time. Therefore, in order to reduce the water hammer, the flow rate control valve 3 may be controlled to reduce the opening / closing speed. In the characteristic example shown in FIG. 3, the water hammer is the smallest in the case of the change in the valve opening degree, which is the characteristic of the reference numeral 300C. In short, when the magnitude of the water hammer exceeds the allowable range of the flow control valve 3, the opening / closing speed of the valve 3 needs to be reduced.

  4 and 5 are diagrams for explaining a method of controlling the opening / closing speed of the flow rate control valve 3 by the controller 100. FIG.

  As shown in FIG. 2, the controller 100 controls the operation of the actuator 4 connected to the flow control valve 3 to control the opening / closing time (opening / closing speed) of the valve 3. Here, when the actuator 4 is an electric motor, the controller 100 controls the opening and closing of the flow rate adjusting valve 3 by the driving time of the electric motor.

  That is, when the controller 100 issues an ON operation command to the electric motor 4, the valve opening degree of the valve 3 increases, and when the operation command is turned OFF, the valve opening degree is maintained. Therefore, as shown in FIG. 4, the opening / closing speed of the valve 3 is determined according to the time ratio between the time T1 for driving the electric motor 4 and the time T2 for not driving.

  Here, the magnitude of the water hammer generated in the flow rate control valve 3 is the pressure difference between the pressure Pc applied to the valve 3 when the valve 3 is fully closed and the pressure Po applied when the valve 3 is fully opened (water introduction). It is proportional to the pressure difference of the system. This pressure difference changes from time to time according to the temporal change in the water level of the reservoir 1 and the landing well 5. For this reason, in order to make the magnitude | size of the water hammer which the flow control valve 3 can accept | permit, the setting of the opening-and-closing speed of the valve 3 according to a pressure difference is needed.

  Normally, the opening and closing speed of the valve 3 is set to a speed at which water hammer does not cause a problem. However, when the pressure difference in the water guide system becomes large, water hammer on the flow rate control valve 3 becomes a problem. Therefore, the upper limit value of the opening / closing speed of the valve 3 is calculated based on the size of the water hammer that the valve 3 can tolerate and the pressure difference of the water guide system. When the calculated value of the upper limit value is smaller than the preset opening / closing speed of the valve 3, the controller 100 changes the set value of the opening / closing speed of the valve 3. Thereby, it becomes possible to suppress the magnitude | size of the water hammer with respect to the flow regulating valve 3, and damage to the valve 3 can be suppressed by controlling the opening-and-closing speed below the allowable pressure of the valve 3.

  Also, the pipe 6 shown in FIG. 1 naturally has an allowable pressure fluctuation value, and the magnitude of the water hammer needs to be less than the allowable value. The controller 100 can also control the pressure fluctuation of the pipe 6 below the allowable value by the above-described control method. Moreover, since it has been confirmed that the occurrence of water hammer is a cause of red water in waterworks, it is possible to suppress the occurrence of red water by suppressing water hammer.

  FIG. 5 is a diagram for explaining a control method of the controller 100 when the actuator 4 is a hydraulic device, for example. In FIG. 5, in the case of a hydraulic device, the opening / closing speed of the valve 3 increases as the time interval T during which the hydraulic pressure is applied is shorter. Therefore, the controller 100 determines the time interval T of the actuator 4 so as to realize an appropriate opening / closing speed of the valve 3, thereby suppressing water hammer on the flow rate adjustment valve 3, so that proper control of the valve 3 can be performed. It becomes possible.

FIG. 6 is a diagram for explaining the relationship between the valve opening degree of the flow control valve 3 and the pressure applied to the valve 3. As shown in FIG. 6, normally, the relationship between the valve opening degree and the pressure of the flow rate control valve 3 shows a non-linear characteristic. Therefore, the pressure difference P1 when the change from the valve opening O ₁ of the flow control valve 3 in O _2, the pressure difference P2 at which changes from the valve opening degree O ₃ in O _4, a change in the valve opening Despite equal amounts, they vary greatly.

  Therefore, even when the opening / closing speed of the flow rate control valve 3 is the same, the magnitude of water hammer caused by the change in the valve opening degree is greatly different. For this reason, in order to suppress water hammer, it is necessary to slow down the opening / closing speed of the flow control valve 3 in the region where the valve opening is small, compared to the region where the valve opening is large.

  Since the flow rate adjusting valve 3 has various relationships between the valve opening and the pressure as shown in FIG. 6 depending on the shape and characteristics thereof, these characteristics are managed as a database. The controller 100 refers to the database and controls the opening and closing speed of the valve 3 so that the pressure change is constant according to the valve opening degree of the flow control valve 3, thereby suppressing the occurrence of water hammer. Is possible.

  In addition, the magnitude of pressure fluctuation that can be a cause of damage to the flow rate control valve 3, damage to the piping 6, and red water is registered in advance in the database as a threshold value. The controller 100 refers to the database, and the pressure fluctuation value estimated from the time ratio between the time T1 for driving the electric motor shown in FIG. 4 and the time T2 for not driving the electric motor or the time interval T shown in FIG. An alarm may be output when the value is exceeded. As a result, it is possible to prevent problems such as damage to the flow control valve 3, damage to the piping 6, and generation of red water.

[Second Embodiment]
FIG. 7 is a diagram illustrating a water conveyance process according to the second embodiment, and is a diagram illustrating a process in which water is guided to the distribution reservoir 16 via the pipe 23 in the water supply plant illustrated in FIG. 1. Taking this process as a specific example, the operation of the control system according to this embodiment will be described.

  As shown in FIG. 7, in the water introduction process, for example, a pipe 23 for introducing water from a reservoir is provided. The introduced water is stored in the reservoir 16 through the flow control valve 15. An actuator 14 such as an electric motor is connected to the flow rate control valve 15.

  The controller 100 outputs a command for controlling the operation of the actuator 14 and changes the opening degree of the flow control valve 15. By the operation of the flow rate control valve 15, the water level 161 of the distribution reservoir 16 changes. This water level 161 is measured by a water level meter 17 installed in the distribution reservoir 16. Reference numeral 160 denotes a water level that is a control target in the reservoir 16.

  FIG. 8 is a diagram showing a change in the water level of the reservoir 16 when the flow rate control valve 15 is opened and closed.

  That is, as shown in FIG. 8, when the flow control valve 15 is open (valve opening Tp), the water level 161 of the water distribution area 16 increases. Conversely, when the valve 15 is closed (valve closed Tc), the water level 161 of the water distribution area 16 decreases. When the water level 161 of the distribution reservoir 16 reaches the control target water level 160, the flow control valve 15 is closed and the water level 161 starts to decrease.

  However, when the water level 161 decreases and does not reach the control target water level 160, the flow control valve 15 is opened again, and the water level 161 rises. On the other hand, when the water level 161 reaches the control target water level 160, the flow control valve 15 is closed again, and the decrease in the water level 161 starts. In such a state, frequent opening and closing of the flow rate control valve 15 is called hunting (water level control abnormality).

  The occurrence of such a hunting phenomenon causes inconveniences such as damage to the flow control valve 15, overheating of the actuator 14, and a water hammer phenomenon of the pipe 23. Therefore, it is necessary to suppress hunting.

  Therefore, the controller 100 estimates that hunting has occurred when the number of times the valve 15 is opened and closed per unit time exceeds a predetermined threshold value. However, when the current water level 161 of the distribution reservoir 16 is not in the vicinity of the control target water level 160, it is highly likely that the valve 15 is opened and closed by normal control of the flow rate control valve 15. Therefore, the controller 100 recognizes that hunting is performed only when the current water level 161 is in the vicinity of the control target water level 160 and the opening / closing frequency of the valve 15 per unit time exceeds the threshold value.

  FIG. 9 is a diagram showing an example of a rainwater drainage plant that is a modification of the present embodiment and is a detection target of hunting.

  In this plant, a rainwater well (pump well) 90 changes its water level 92 due to the inflow of rainwater, and the change is measured by a water level meter 91. The controller controls the current water level 92 to be equal to or lower than the water level target value (control target water level) 93 so that rainwater does not overflow from the rainwater well 90. Specifically, the controller controls the water level of the rainwater well 90 by driving and controlling a drain pump 95 connected to the pipe 94.

  The controller operates the drainage pump 95 and stops the drainage pump 95 when the current water level 92 of the rainwater well 90 falls below the control target water level 93. On the other hand, when the current water level 92 of the rainwater well 90 rises, the drainage pump 95 is operated again to drain the current water level 92 of the rainwater well 90.

  Also in this modified example, when the current water level 27 of the rain well 90 approaches the control target water level 93, hunting (water level control abnormality) may occur. When the deviation between the water level target value 93 and the current water level 92 is small and the number of opening / closing commands of the drain pump 95 exceeds the set upper limit number of times within a preset unit time, the controller detects that the water level control abnormality has occurred. Recognize and report that it has occurred.

  As described above, according to the present embodiment, by estimating (recognizing) occurrence of hunting (water level control abnormality), damage to the flow control valve 15, overheating of the actuator 14, water hammer phenomenon of the pipe 23, and the like. Measures can be taken to suppress hunting before inconvenience occurs.

[Third Embodiment]
FIGS. 10 to 12 are diagrams for explaining a water supply plant control system according to the third embodiment.

  The control system of the waterworks plant controls the water supply pressure and the water supply flow rate by driving control of a water distribution pump or a water supply pump, and executes control in which the control target changes with time. As shown in FIG. 10, in the discharge pressure of the water distribution pump, when the control target 400 changes in a step shape, the actual discharge pressure changes with an overshoot as shown by the actual response 410 shown by a broken line, Some time (settling time Ts) is required until the control target 400 is settled.

  FIG. 11 shows the relationship between the settling time Ts and the control target change amount (target change amount 420). That is, as the target change amount increases, the settling time tends to increase. With regard to these functional relationships, when civil engineering parameters including a pump and control parameters such as PID control are determined, an approximate function can be created by using data obtained from actual plant operation. In FIG. 11, a solid line is a typical example of the approximate function with respect to the settling time upper limit value 510 and the settling time lower limit value 520 indicated by dotted lines, and shows a settling time estimated value 500.

  However, when plant secular change or water pressure fluctuation occurs, there is a discrepancy between the obtained approximate function and the measured data. Therefore, when the control target changes, the control system of this embodiment calculates an estimated settling time from the target change amount using an approximation function, and compares the settling time actually measured in the plant. Based on the results of the comparison, the control system will control abnormalities such as abnormal control parameters due to aging of the plant and abnormal pressure fluctuations in the piping system when the settling time deviates from the upper and lower limits. Outputs that occurred. Thereby, it is possible to suppress the occurrence of “non-water discharge”, “control instability” and the like in the water supply plant.

  FIG. 12 is a diagram illustrating an example of a two-dimensional table for the control system of the present embodiment to refer to an appropriate settling time according to a change in control target. This two-dimensional table has two values for a plant whose settling time varies depending on the current discharge pressure value and the changed discharge pressure target size when the discharge pump discharge pressure target changes. It contains information for referring to the proper settling time. By using the two-dimensional table, the control system of the present embodiment outputs that a control abnormality has occurred when the difference from the actually observed settling time exceeds a threshold value.

  In the control system of the present embodiment, the control of the flow rate of the water distribution pump is similarly performed by executing the control method described with reference to FIG. 10 to FIG. It is possible to detect and output.

  As described above, the control system of each embodiment uses the measurement value obtained from the sensor used for controlling the water supply plant and the signal in the control device to specify the diagnosis algorithm, and to set the abnormality judgment standard. By making it the same, it is possible to monitor and detect abnormality of waterworks plant equipment with high accuracy. As a result, it is possible to make the diagnosable target changed by the operator who performs diagnosis and monitoring of the plant and the diagnosis result uniform.

  In addition, although each embodiment demonstrated the waterworks plant as a specific example, it is not restricted to this, For example, it can apply to various water treatment plants, such as a sewerage plant.

  Note that the present invention is not limited to the above-described embodiment as it is, and can be embodied by modifying the constituent elements without departing from the scope of the invention in the implementation stage. In addition, various inventions can be formed by appropriately combining a plurality of components disclosed in the embodiment. For example, some components may be deleted from all the components shown in the embodiment. Furthermore, constituent elements over different embodiments may be appropriately combined.

The figure for demonstrating the structure of the waterworks plant regarding each embodiment of this invention. The figure which shows the water conveyance process regarding 1st Embodiment. The figure which shows the relationship between the opening degree of the flow control valve regarding this embodiment, and the time concerning opening and closing. The figure for demonstrating the method to control the opening-and-closing speed of the flow control valve concerning this embodiment. The figure for demonstrating the method to control the opening-and-closing speed of the flow control valve concerning this embodiment. The figure which shows the relationship between the valve opening degree and pressure of a flow control valve regarding this embodiment. The figure which shows the water conveyance process regarding 2nd Embodiment. The figure which shows the water level change of the distribution reservoir regarding 2nd Embodiment. The figure for demonstrating the modification regarding 2nd Embodiment. The figure which shows the control characteristic of the discharge pressure of the pump in control regarding 3rd Embodiment. The figure which shows the relationship between the settling time in the control regarding 3rd Embodiment, and target variation | change_quantity. The figure which shows the two-dimensional table of settling time in control regarding 3rd Embodiment.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 ... Reservoir (dam), 2 ... Flow meter, 3, 15 ... Flow control valve, 4, 14 ... Actuator 5 ... Irrigation well, 6, 23, 27 ... Piping, 9 ... Mixing pond, 10 ... Flock formation pond,
DESCRIPTION OF SYMBOLS 11 ... Sedimentation basin, 12 ... Filtration pond, 13 ... Purification pond, 16 ... Distribution pond, 17 ... Water level meter,
30 ... River, 32 ... Sedimentation basin, 34 ... Pump well, 39 ... Sludge pond, 40 ... Sewage pond,
100: Controller.

Claims (13)

Apply water treatment such as water purification to water from a water source, and apply to a water treatment plant having a reservoir for storing the water and a piping system for passing pressurized water from the reservoir to the treatment pond In the control system,
A flow control valve provided in the piping system for adjusting the flow rate of water flow;
Control means for controlling the opening and closing of the flow rate control valve, and for controlling the opening and closing speed of the flow rate control valve based on a pressure difference applied to the flow rate control valve according to the opening and closing of the flow rate control valve. Control system. The control means includes
When the magnitude of the water hammer generated when the change in the opening of the flow rate control valve per unit time is large exceeds the allowable range of the flow rate control valve or the piping system, the opening / closing speed of the flow rate control valve is reduced. The control system according to claim 1, wherein the control system is controlled to be relatively small. The control means includes
An upper limit value of the opening / closing speed of the flow rate control valve is calculated on the basis of the magnitude of the water hammer and the pressure difference that the flow rate control valve or the piping system can tolerate, and the upper limit value is calculated based on a preset reference opening / closing speed. The control system according to claim 1, wherein if the value is smaller, control is performed so as to change the set value of the reference opening / closing speed. The control means includes
In order to suppress the amount of change in the opening of the flow control valve per unit time, an upper limit of the operation duration of the flow control valve is set, and the flow control valve is controlled not to continuously operate beyond the set time. The control system according to claim 1. The control means includes
In order to suppress the amount of change in the opening of the flow control valve per unit time, an upper limit is set for the operation interval of the flow control valve, and control is performed so that the flow control valve does not operate at a shorter interval than the set time. The control system according to claim 1. The control means includes
When the flow control valve has a characteristic in which the pressure change according to the change in the same valve opening amount varies depending on the valve opening state, prepare a database in which the relationship between the valve opening degree and the pressure change is accumulated in advance. ,
Referring to the database, the amount of pressure change associated with the change in the valve opening is calculated, and the operation duration or operation of the flow control valve is set so that the amount of pressure change per unit time does not exceed the set upper limit value. The control system according to claim 1, wherein the interval is controlled. The control means includes
4. The system according to claim 3, wherein the set upper limit value is compared with the operation amount of the flow rate control valve, and an alarm is output when the operation amount exceeds the upper limit value. 6. The control system according to any one of items 5. In a control system applied to a water treatment plant having a reservoir for storing water and a piping system for passing pressurized water from the reservoir to a distribution reservoir,
A flow control valve provided in the piping system for adjusting the flow rate of water flow;
A water level meter for measuring the water level ring of the reservoir;
Controlling the opening and closing of the flow control valve, and when the number of opening and closing per unit time of the flow control valve exceeds the set upper limit, and the deviation between the current water level of the reservoir and the target water level by the water level gauge And a control means including a function of estimating that a water level control abnormality has occurred when the water level is small. In a control system applied to a water treatment plant having a pump well that temporarily stores water for drainage,
A drainage pump for draining the pump well;
A water level meter for measuring the water level of the pump well;
The drain pump is driven and controlled, the deviation between the current water level of the pump well by the water level gauge and the water level target value is small, and the upper limit set by the number of opening / closing commands of the drain pump within the preset unit time And a control means including a function of estimating that a water level control abnormality has occurred when the number of times is exceeded. In a control system applied to a water treatment plant having a water distribution pump,
When the control target of the water distribution pump has changed, the difference between the settling time of the control estimated from the absolute value of the target change amount and the actually observed settling time has exceeded a preset threshold value. A control system characterized by comprising control means for outputting that a control abnormality has sometimes occurred. The control means includes
When the pressure target or flow rate target of the water distribution pump changes as the control target, the difference between the control settling time estimated from the absolute value of the target change amount and the actually observed settling time is set in advance. 11. The control system according to claim 10, wherein a control abnormality is output when the measured threshold value is exceeded. The control means includes
When the discharge pressure target of the water distribution pump is changed as the control target, the settling time of control obtained from a two-dimensional table referred to by the two values of the current discharge pressure value and the changed discharge pressure target value 11. The control system according to claim 10, wherein a control abnormality is output when a difference between the actual settling time and the actually observed settling time exceeds a preset threshold value. The control means includes
When the flow rate control of water distribution is performed using the discharge volume target of the water distribution pump as the control target, and the discharge volume target changes, the current discharge volume value and the changed discharge volume magnitude Control abnormality occurs when the difference between the settling time of the control obtained from the two-dimensional table referenced by the two values and the actually observed settling time exceeds a preset threshold value The control system according to claim 10, wherein the information is output.

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