JP3903653B2 - Water distribution facility control equipment - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a water distribution facility control apparatus for controlling a water distribution reservoir and controlling the amount of water supplied to the water distribution reservoir in a water distribution facility.
[0002]
[Prior art]
The distribution reservoir is described in “Water Supply Facility Design and Commentary” (supervised by the Ministry of Health and Welfare, 1990 edition) as follows. Reservoir is a reservoir that receives water from the water treatment plant and distributes water according to the amount of demand in the distribution area. Along with the function to adjust the time fluctuation of the water distribution, an accident occurs upstream of the reservoir. It is necessary to have a function capable of maintaining a predetermined amount of water and water pressure at times.
[0003]
On the other hand, since the water purification facility is based on the planned maximum daily water supply, a fixed amount of purified water is sent to the reservoir every hour. As control of the distribution reservoir, it is required to satisfy these two conditions in a well-balanced manner. Although it is difficult to say that the current technology completely satisfies the requirements of “design and explanation of water supply facilities”, typical control includes level control at constant water level and water level set at each time. It is done.
[0004]
FIG. 5 is a schematic configuration diagram of a distribution facility in which conventional distribution reservoir water level control is applied to control of the number of pumps. 1 is a water reservoir, and 2 is a water level meter that measures the water level of the distribution reservoir 1. Reference numeral 3 denotes a water pump composed of a plurality of units that feeds water from the water purification plant 7 to the distribution reservoir 1. These water pumps 3 are controlled by a pump start / stop command from the pump number control unit 4. The number-of-pumps control unit 4 determines the number of operating pumps based on a signal from the water level gauge 2. 5 is a pipe network of the water distribution area.
[0005]
In the distribution facility configured as described above, when the current water level of the distribution reservoir 1 is higher than the set maximum water level HWL (all pumps stopped), the pumps are all stopped, but the water levels are as follows: In this case, the number of operating pumps is controlled as follows.
[0006]
When the current water level becomes higher than the pump control water level 1 (LT1), one pump is operated from the following equation. LWL is a set minimum water level.
[0007]
LT1 = ((HWL−LWL) / 5) × 1−HWL
Next, when the current water level becomes higher than the pump control water level 2 (LT2), two pumps are operated from the following equation.
[0008]
LT2 = ((HWL−LWL) / 5) × 2−HWL
Hereinafter, when the current water level becomes higher than the pump control water level 3 (LT3), the pump is operated from the following formula,
LT3 = ((HWL−LWL) / 5) × 3-HWL
When the current water level becomes higher than the pump control water level 4 (LT4), four pumps are operated from the following equation.
[0009]
LT4 = ((HWL−LWL) / 5) × 4-HWL
If the current water level is lower than LT4, 5 pumps are operated.
[0010]
[Problems to be solved by the invention]
As described above, the distribution pond of the distribution facility is required to have a buffer function of “time fluctuation of the distribution amount”. The simplest control is the constant water level control, but the constant water level control has little buffer function. Although the control method for setting the target water level for each hour considering the time variation of the water distribution has achieved some results, the daily distribution pattern is not constant, so there are problems that frequently occur days that do not operate well There is.
[0011]
In addition, the distribution reservoir is required to have the capacity to distribute water when an accident occurs upstream from the distribution reservoir. In order to better satisfy this requirement (accident response), the effective water depth is always set high for the water level of the reservoir. However, the requirements for the "buffer function" and "accident response" are contradictory requirements, and it is necessary to perform control that satisfies these requirements, but such ideal control has not been achieved at present. .
[0012]
By the way, many reservoirs are actually operated and often receive water from water purification plants. In water treatment plants that supply water to multiple reservoirs, the amount of water supplied to each reservoir is often controlled. However, in practice, it is difficult to perform ideal control. This is a problem mainly caused by the complicated changes in water distribution.
[0013]
The water supply part of the water supply facility is operated by a wide-area water supply entity, and each water distribution facility is often operated by a local government. Usually, since there is no transmission / reception function of the distribution amount data between the facilities of the wide area water supply entity and the local government, the distribution amount cannot be directly measured and used in the process of determining the amount of water supply.
[0014]
The present invention has been made in view of the above circumstances, and provides a water distribution facility control apparatus that obtains the amount of water distribution from the water level of the water reservoir and the amount of water supplied to the water reservoir, and performs water distribution facility control using demand prediction. The task is to do.
[0015]
[Means for Solving the Problems]
To achieve the above object, the present invention provides a plurality of water pumps, a water reservoir that receives water from a water purification plant by these water pumps, and distributes water to the water distribution area, and is installed in the water reservoir. In a water distribution facility control apparatus comprising a water level meter that measures the water level of the water pump, and a pump number control unit that is controlled according to the water level data measured by the water level meter and that sends a start / stop command for the plurality of water pumps,
A flow control valve for controlling the amount of water delivered to the reservoir, a flow meter for measuring the amount of water delivered, a flow meter for measuring the amount of water delivered, and the measured amount of water delivered to the reservoir. Water level data is supplied, and the flow rate calculation device for calculating the target flow rate value from these, and the pump flow rate control unit is controlled by the target flow rate value calculated by the flow rate calculation device, and the target flow rate value and the flow meter A flow rate control device that controls the flow rate control valve so that the measured water supply amount is supplied and matches the target flow rate value ;
The flow rate calculation device includes a water flow rate calculation unit that calculates a water flow rate per hour based on a value measured by a flow meter and a water level data measured by a water level meter. A forecast unit that calculates the predicted water level from the forecasted water volume predicted by the demand forecasting unit and the current water level data by the water level meter, which forecasts demand using the amount of water distribution per hour and past data By configuring the water level calculation unit and the flow rate calculation unit that calculates the target flow rate value from the predicted water level obtained by the predicted water level calculation unit and the value measured by the flow meter, the function of the water distribution facility can be achieved only by water supply control. This makes it possible to use automatic control, to stabilize the amount of water supply, and to operate the pump stably.
[0017]
Further, the demand prediction unit stores the water distribution amount per hour calculated by the water distribution amount calculation unit in a time series as integrated data of unit time, and the past water distribution time series data is delayed by n dimensions and t time. By adopting the chaotic demand forecast embedded in the state space, it is possible to predict the reservoir water level in the future and automatically control the distribution facility.
[0018]
DETAILED DESCRIPTION OF THE INVENTION
Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 is a schematic configuration explanatory view of a water distribution facility control apparatus showing an embodiment of the present invention. In FIG. 1, water introduced from a river or the like is purified at a water purification plant 11 and temporarily stored in a water purification pond (not shown). The purified water stored in the water purification pond is sent to the distribution reservoirs 15a and 15b through the water supply pipes 26 by a plurality of water supply pumps 12. In the middle of the water supply pipeline 26, flow rate control valves 13a and 13b and flow meters 14a and 14b are provided. From the reservoirs 15a and 15b, purified water is distributed to the pipe networks of the respective distribution areas 16a and 16b according to the amount of demand water. The water pump 12 is controlled by a pump number control unit described later.
[0019]
The water reservoirs 15a and 15b are provided with water level meters 17a and 17b, and the water level signals obtained by the water level meters 17a and 17b are supplied to the integrated control device 18. The integrated control device 18 is composed of the flow rate calculation devices 19a and 19b and the pump number control unit 20, and the flow rate calculation devices 19a and 19b have the same configuration. Therefore, the flow rate calculation device 19a will be described below as an example.
[0020]
The flow rate calculation device 19a includes a water flow rate calculation unit 21 that calculates a water flow rate per hour from a value measured by the flow meter 14a and a value from the water level meter 17a, and a water flow rate calculation unit. Demand prediction unit 22 that performs demand prediction using the amount of water distribution per hour calculated in 21 and past data, and prediction from the predicted water distribution amount predicted by this demand prediction unit 22 and the current water level by water level meter 17a It is comprised from the predicted water level calculating part 23 which calculates a water level, and the flow volume calculating part 24 which calculates a target flow value from the predicted water level obtained by this predicted water level calculating part 23 and the value measured by the flowmeter 14a.
[0021]
The target flow rate value calculated by the flow rate calculation unit 24 is supplied to the flow rate control device 25a. A value measured by the flow meter 14a is also input to the flow control device 25a, and the flow control valve 13a is adjusted by an output from the flow control device 25a so that the measured value matches the target flow value. The target flow rate value calculated by the flow rate calculation unit 24 is also supplied to the pump number control unit 20 so that the number of pumps is controlled to match the target flow rate value.
[0022]
The above control is for the distribution reservoir 15a, but similarly for the distribution reservoir 15b, it is controlled by the outputs of the flow rate calculation device 19b and the flow rate control device 15b. The same control is performed when there are three or more reservoirs.
[0023]
Next, details of each calculation unit and prediction unit of the flow rate calculation device 19a will be described.
[0024]
(1) The water distribution amount of the water distribution amount calculation unit 21 is calculated by the following formula.
[0025]
Qout = ΣQin + (LL−L0) × S
Qout: Amount of water distribution (for 1 hour)
ΣQin: Amount of water supply (1 hour integration)
LL: Reservoir level (1 hour ago)
L0: Distribution reservoir water level (current value)
S: Reservoir bottom area (2) The demand forecasting unit 22 employs a demand forecasting method based on chaos theory. This prediction method was adopted because the results were the best among the demand prediction methods studied. This prediction method performs demand prediction using the water distribution amount calculated by the water distribution amount calculation unit 21 and predicts the water distribution amount per hour as 1 hour, 2 hours, 3 hours, and so on.
[0026]
The chaos demand forecasting method is described below. The demand prediction unit 22 stores the water distribution amount in a time series as unit time integrated data, and embeds the time series data of the past water distribution amount in an n-dimensional, t-time delayed state space.
[0027]
First, a vector (y (t), y (t-τ), y (t-2τ), ... y (t- (n-1) τ)) is created from the time series data y (t) of water distribution ( τ is the delay time). This vector represents one point in the n-dimensional reconstruction state space “R ⁿ ”. Accordingly, when the time t is changed, a trajectory can be drawn in this n-dimensional reconstructed state space. This is shown in FIG. As shown in FIG. 2, the data vector z (T) obtained by the latest observation is plotted in the n-dimensional reconstructed state space, the data vector in the vicinity thereof is x (i), and x (i) Let x (i + s) be the state after s steps. Then, a predicted value of the data vector z (T + s) of s steps ahead to be predicted (hereinafter, the predicted value is denoted by symbol ∧) is set as ∧z (T + s). This is shown in FIG. The change of the state x (i) to the state x (i + s) after the s step can be expressed by a linguistic expression using x (i) and x (i + s) as follows.
[0028]
IF x (T) is x (i) THEN x (T + s) is x (i + s) (1)
In this equation (1), x (T) is a set representing a data vector in the vicinity of z (T) in the n-dimensional reconstruction state space, and x (T + s) is a data vector after s steps of x (T). X (i) is a data vector in the vicinity of z (T), so the dynamics from state z (T) to state z (T + s) are changed from state x (i) to state x. It can be estimated from the dynamics of (i + s).
[0029]
The attractor embedded in the n-dimensional reconstruction state space is a smooth manifold, and the trajectory from z (T) to z (T + s) is affected by the Euclidean distance from z (T) to x (i). The by the way,
x (i) = (y (i), y (i-τ), y (i-2τ), ... y (i- (n-1) τ)) (2)
x (i + s) = (y (i + s), y (i + s-τ), y (i + s-2τ), ... y (i + s- (n-1) τ))
Therefore, when focusing on the j-axis in the n-dimensional reconstructed state space, Equation (2)
IF aj (T) is yj (i) THEN aj (T + s) is yj (i + s) (j = 1 to n) (3)
Here, aj (T) is the j-axis component in the n-dimensional reconstruction state space of the neighborhood value x (i) of z (T), and aj (T + s) is the n-dimensional reconstruction of x (i + s). The j-axis component in the configuration state space, n is the number of embedding dimensions.
[0030]
Also, the trajectory from z (T) to ∧z (T + s) is affected by the vector distance from z (T) to x (i), but the embedded attractor is a smooth manifold, This is subject to nonlinear effects. Therefore, in order to make the mapping from x (T) to x (T + s) non-linear, when the expression (3) is expressed by a fuzzy function, the following expression is obtained.
[0031]
IF aj (T) is (i) THEN aj (T + s) is (i + s) (j = 1〜n)… （4）
By the way, since z (T) = (y (T), y (T-τ), y (T-2τ), ... y (T- (n-1) τ)), n of z (T) The j-axis component in the dimensional reconstruction state space is yj (T). Therefore, the j-axis component of the predicted value ∧z (T + s) to the data vector z (T + s) after s steps of the data vector z (T) is expressed as yj (T) in the expression (4). By substituting T) and performing fuzzy inference, it can be obtained as aj (T + s).
[0032]
(3) The predicted water level calculation in the predicted water level calculation unit 23 is performed for each of the reservoirs 15a and 15b. First, each reservoir 15a. The predicted water level is calculated for 15b. The predicted water level until after the unit time adopted by the demand prediction unit 22 is calculated.
[0033]
The predicted water level (L1) after 1 hour is L1 = (Q0−Q1) / S + L0
The predicted water level (L2) after 2 hours is L2 = (Q0−Q2) / S + L1
Similarly, the predicted water level from 3 hours to 12 hours is calculated as follows.
[0034]
L3 = (Q0-Q3) / S + L2
L4 = (Q0-Q4) / S + L3
L5 = (Q0-Q5) / S + L4
・
・
・
L12 = (Q0−Q12) / S + L11
In addition, the meaning of each said code | symbol is shown below.
[0035]
S: Distribution reservoir bottom area L0: Current water level L1: Water level L2 after 1 hour: Water level L2 after 2 hours: Water level L3 after 3 hours L4: Water level after 4 hours L5: Water level after 5 hours L6: After 6 hours Water level L7: water level L7 after 7 hours: water level L9 after 8 hours: water level L10 after 9 hours: water level L10 after 10 hours: L11: water level after 11 hours L12: water level after 12 hours Q0: per hour Water supply amount of water pump (accumulation of current value)
Q1: Estimated water distribution after 1 hour (per unit time)
Q2: Estimated water distribution after 2 hours (per unit time)
Q3: Estimated water distribution after 3 hours (per unit time)
Q4: Estimated water distribution after 4 hours (per unit time)
Q5: Estimated water distribution after 5 hours (per unit time)
Q6: Expected water distribution after 6 hours (per unit time)
Q7: Expected water distribution after 7 hours (per unit time)
Q8: Estimated water distribution after 8 hours (per unit time)
Q9: Estimated water distribution after 9 hours (per unit time)
Q10: Expected water distribution after 10 hours (per unit time)
Q11: Estimated water distribution after 11 hours (per unit time)
Q12: Estimated water distribution after 12 hours (per unit time)
(4) The flow rate calculation unit 24 lowers the flow rate set value when the predicted water level is higher than HWL within the range of the preset predicted effective number (ET), and sets the preset predicted effective number (ET ) If the predicted water level is lower than LWL, the flow rate set value is increased.
[0036]
HWL: Flow rate decreasing water level LWL: Flow rate increasing water level ET: Predicted effective number FIG. 4 shows a trend graph as a result of controlling the reservoir using the embodiment configured as described above. The set values at this time are as follows.
[0037]
HWL: 9m
LWL: 7m
Unit time: 1 hour ET: 6
Control period: 1 hour Reservoir effective depth: 10m.
[0038]
In addition, despite the severe conditions of water level 7m-9m (water storage rate 70% -90%), the water level of the reservoir is being operated stably and in good condition, and at the same time the water supply flow rate is also stable. Therefore, the operation of the reservoir is good. The 7-day pump shown in FIG. Since the flow rate is operated on average, the number of pumps is operated stably.
[0039]
As mentioned above, the water supply part of this water supply facility is operated by a wide-area water supply entity, and each water distribution facility is operated by a local government. Since there is no function to send and receive water distribution data between the facilities of the wide area water supply business and the local government, it is not possible to directly measure and use the water distribution in the process of determining the water supply. However, according to the present invention, there is an advantage that the water level of the distribution reservoir operated by the local government can be ideally controlled only by the control facility of the wide area water supply business entity.
[0040]
【The invention's effect】
As described above, according to the present invention, the following effects can be obtained.
(1) By determining the amount of water distribution from the water level of the distribution reservoir and the amount of water delivered to the reservoir, and controlling the distribution facility using demand forecast, the functions of the distribution facility can be made use of only the distribution control device that has no data on the distribution amount. Automatic control will be possible.
(2) Opening the flow control valve using only the water supply control device that has no data on the amount of water distribution by calculating the water distribution amount from the water level of the distribution reservoir and the amount of water delivered to the reservoir, and controlling the distribution facility using demand forecast The number of changes can be reduced, and the durability of those facilities and equipment can be improved by using them with care.
(3) By determining the amount of water distribution from the water level of the distribution reservoir and the amount of water delivered to the reservoir, and controlling the distribution facility using demand forecast, the pump can be operated stably only with the water supply control device that has no data on the distribution amount. This will enable energy-saving operation.
(4) To determine the amount of water distribution from the water level of the distribution reservoir and the amount of water delivered to the reservoir, and to control the distribution facility using demand prediction, to stabilize the amount of water supply only with a water supply control device that has no data on the amount of water distribution. It is possible to stabilize the amount of water produced at the water purification plant.
[Brief description of the drawings]
FIG. 1 is a schematic configuration explanatory view showing an embodiment of the present invention.
FIG. 2 is an explanatory diagram of embedding time-series water distribution data in an n-dimensional reconstruction space.
FIG. 3 is an explanatory diagram of dynamics from x (T) to x (T + s).
FIG. 4 is a seven-day trend graph using the embodiment.
FIG. 5 is a schematic configuration diagram of a water distribution facility in which conventional water level control of a distribution reservoir is applied to control of the number of pumps.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 11 ... Water purification plant 12 ... Water supply pump 13a, 13b ... Flow control valve 14a, 14b ... Flowmeter 15a, 15b ... Distribution reservoir 16a, 16b ... Distribution area 17a, 17b ... Water level meter 18 ... Integrated control apparatus 19a, 19b ... Flow calculation Device 20 ... Number-of-pumps control unit 21 ... Water distribution amount calculation unit 22 ... Important prediction unit 23 ... Predicted water level calculation unit 24 ... Flow rate calculation units 25a, 25b ... Flow rate control device

Claims (2)

A plurality of water pumps, a water reservoir that receives water from the water treatment plant by these water pumps, distributes water to the water distribution area, a water level meter that is installed in this water reservoir and measures the water level of the water reservoir, and In the water distribution facility control device, which is controlled according to the measured water level data, and includes a pump number control unit that sends start and stop commands of the plurality of water pumps,
A flow control valve for controlling the amount of water delivered to the reservoir, a flow meter for measuring the amount of water delivered, a flow meter for measuring the amount of water delivered, and the measured amount of water delivered to the reservoir. Water level data is supplied, and the flow rate calculation device for calculating the target flow rate value from these, and the pump flow rate control unit is controlled by the target flow rate value calculated by the flow rate calculation device, and the target flow rate value and the flow meter A flow rate control device that controls the flow rate control valve so that the measured water supply amount is supplied and matches the target flow rate value ;
The flow rate calculation device includes a water flow rate calculation unit that calculates a water flow rate per hour based on a value measured by a flow meter and a water level data measured by a water level meter. A forecast unit that calculates the predicted water level from the forecasted water volume predicted by the demand forecasting unit and the current water level data by the water level meter, which forecasts demand using the amount of water distribution per hour and past data A water distribution facility control apparatus comprising: a water level calculation unit; and a flow rate calculation unit that calculates a target flow rate value from a predicted water level obtained by the predicted water level calculation unit and a value measured by a flow meter . The demand prediction unit stores the water distribution amount per time calculated by the water distribution amount calculation unit in a time series as unit time integrated data, and stores the past water distribution time series data in an n-dimensional, t-time delayed state space. The water distribution facility control device according to claim 1, wherein the chaotic demand forecast is embedded.

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