JPH0352001A - Predictive operation controller for conveying pump - Google Patents

Abstract

PURPOSE:To perform proper conveying pump operation and obtain a proper a water reservoired amount by calculating the upper and lower limit water levels of a distributing reservoir of a specific time at optional time from demand prediction, planning the number of conveying pumps to be operated for water storage, and putting the conveying pump in operation according to the plan. CONSTITUTION:The quantity of water stored of the specific time at the optimum time is calculated from the demand prediction and the target water level of the distributing reservoir is calculated from the found amount. The target water levels are the lower limit water level at which water is stored for a certain time and the upper limit water level calculated from the stored quantity of a longer period. Then conveying pump operation is so planned that the water level of the distributing reservoir is in the range between the target water levels. Consequently, water can be stored in the distributing reservoir by the optimum amount corresponding to daily demand and even when the demand is small, water can be fed with a proper water level, so the power cost for the pumps is reduced.

Description

[Detailed Description of the Invention] A. INDUSTRIAL APPLICATION FIELD The present invention relates to a water pump predictive operation control device for controlling the operation of a water pump based on demand forecasts in a water purification plant or the like.

B. Summary of the Invention The present invention calculates the upper and lower limit water levels of a water distribution reservoir for a predetermined time at any time from the demand forecast, and calculates the number of operating water pumps for water storage in the operation of a water distribution reservoir and water pump operation based on a demand forecast. By planning and operating the water pump based on the plan, proper water pump operation and appropriate water storage amount can be obtained based on the plan.

C. Conventional Technology The water level in a water distribution reservoir changes depending on the difference between the amount of demand and the amount of water delivered, but depending on how the water pump is operated, the water level can be kept constant or can vary greatly. In addition, various proposals are being made regarding operation control means for reducing the frequency of operation switching of the water pump. These operation methods have various advantages, but on the other hand, there are various problems as described below, and there is no method of operating a water distribution reservoir that solves all of these problems, and there are various methods that suit the situation and purpose of each facility. Currently, it is done in a way that satisfies one condition but sacrifices other characteristics.

D. Problems to be Solved by the Invention As mentioned above, the method of keeping the water level constant near the upper limit of the water distribution reservoir is advantageous in dealing with abnormal situations such as power outages and deterioration of purified water quality, but the water transmission power cost is high. As the size increases, the frequency of starting and stopping of the pump increases. On the other hand, if it is kept constant near the lower limit, the power cost for water supply will be reduced, but the amount of water stored will be small, which is a concern in preparing for abnormal situations. In addition, if the water pump is operated to reduce the frequency of switching, the water level in the distribution reservoir will fluctuate significantly, and the water level may drop during peak demand periods, which may impede stable supply in response to changes in demand. be.

It is also conceivable to use demand forecasting to predict water level changes in water distribution reservoirs in advance one day, formulate an optimal operation plan, and automatically operate water pumps, etc. based on this operation plan.
Due to errors in demand forecasts and circumstances at the water treatment plant, the final decision is left to the operator's discretion. For this reason, there is a need for a system that supports the planning of an operation plan that allows an operator to disconnect f'lJ at the planning stage of the operation plan.

The present invention solves the above-mentioned problems, and its purpose is to:
By predicting the amount of water demand, calculating the amount of stored water for a predetermined amount of time from this demand forecast, and determining the upper and lower limit water levels of the water distribution reservoir based on the calculation results, it is possible to improve the operating efficiency of the water pump and to ensure stable water storage. An object of the present invention is to provide a water pump predictive operation control device.

E. Means for Solving the Problems In order to achieve the above object, the present invention calculates the amount of stored water for a predetermined time at any time from the demand forecast, and sets the water level determined based on the calculation result to the lower limit water level of the water distribution reservoir. The water level determined from the amount of stored water for a time longer than the predetermined time at the arbitrary time is set as the upper limit water level, and the water pump operation for water storage is set so that the water level in the distribution reservoir falls within the upper limit water level range. A water pump predictive operation control device is constituted by a calculation means for making a plan and a control means for switching the number of water pumps in operation according to the operation plan of the calculation means.

F. When storing water in a water distribution reservoir, etc., calculate the amount of water stored for a certain time at any given time based on the demand forecast, set the water level calculated from this amount of water as the lower limit water level of the distribution reservoir, and calculate the amount of stored water for a longer time at the same time. The water level determined from the above is set as the upper limit water level, and the water pump operation plan is established so that the water level in the distribution reservoir falls within this water level range. In addition, the operator can easily modify this plan using a man-machine machine, predict the water level in the water distribution reservoir, and control the water pump operation according to the created plan.

G. EXAMPLES Examples of the present invention will be described below with reference to FIGS. 1 to 4.

FIG. 1 shows the configuration of a water pump predictive operation control device according to an embodiment of the present invention, where l is an operator station for monitoring operation, 2 is a computer for operation management, 3 is a data artery, and 4a to 4d are data conversion units. 5a to 5d are local area networks, 6a to 6d are programmable controllers, 7a to 7c are auxiliary relay boards, 8 is a pump station, 9 is a chemical injection facility, and 10 is a sedimentation tank.

In the first device, at the operator station l for monitoring operation, the operator can check the status of the pump station 8, chemical injection equipment 9, and sedimentation tank 10, which are controlled stations, on the display unit (CRT).
monitor and perform predetermined control operations. The computer 2 executes predetermined calculation control according to the state of each controlled station. That is, the operating status of the water pump, the status of the chemical injection equipment 9, and the status of the sedimentation tank 10 in the pumping station 8 are determined by the auxiliary relay boards 7a to 7c, the program controllers 6b to 6d, the networks 5b to 5d, and the data converters 4b to 4d. and is reported to the operator station l and the computer 2 via the data artery 3. The computer 2 executes arithmetic processing according to information from each controlled station and instructions from the operator station 1, and sends arithmetic commands to the program controller via the data artery 3, data converters 4b to 4d, and networks 5b to 5d, respectively. Lead to 6b-6d. Program controllers 6b to 6d execute predetermined control operations in response to instructions from computer 2, and auxiliary relay boards 7a to 7d.
Each controlled station is controlled via 7C.

The present invention is characterized by the control of a pump station, and as an example thereof, K time storage ffiQMi at time i is
is expressed by the following equation using the predicted demand QDi.

FIG. 3 shows an example where K=6. The upper part of Figure 3 shows the time-series changes in the amount of water delivered by the pump and the predicted demand, and the lower part shows the changes in the water level of the water distribution reservoir at that time. The shaded area is the 6-hour storage amount at 1:00 am. The target water level at 1 a.m. to maintain this storage amount is HJi = QMi/A, where A is the cross-sectional area of the distribution reservoir.
......(2). This is for one day (the calculation is l
If the water level is calculated for 24 times (if it is carried out once per hour), the water level will look like the 6-hour storage curve in Figure 3.

Similarly, the storage water level for k+1 hours is calculated by formula (1) where k is k+l.
Figure 3 shows an example where the time is set to 7 hours. The water pump is controlled so that the water level changes within this range, with the k-hour water level as the lower limit and the k+1-hour storage water level as the upper limit.

In other words, the next number of pumps in operation at time i is the number of pumps at time i.
Assuming that the number of pumps operated at the time is the same, if the water level is within this upper limit, the number of pumps in operation is reduced by one, if it exceeds the upper limit, the number of pumps in operation is reduced by one, and if it is at the lower limit, it is increased by one. The amount of water supplied by the number of pumps in operation determined in this manner is defined as the amount of water supplied by the pump, and the water distribution levels at that time are shown in FIG. 3. The value of k can be set arbitrarily depending on the facility and operation type, and the upper limit water level is also 1 as the number of hours added to the lower limit storage amount.
It's not limited to time.

The water pump operation plan determined in this way becomes the final plan if there are no problems in the judgment of the operator, but depending on the type of demand, the number of pump starts and stops may increase and it may need to be revised. There are cases. For example, in the example shown in FIG. 4, it is preferable to correct it. Here, from 3:00 pm to 4:00 pm, there are two water pumps, but this returns to one every hour. On the other hand, in this example it starts from 16:00! until 7pm 2
When one pump is operated from 18:00 to 19:00, the water level changes as shown by the broken line curve e. The corrected water level will be In such a case, the upper limit is slightly exceeded, but there is still some margin before reaching the physical upper limit water level, so the latter operation, which reduces the frequency of starting and stopping, is preferable. In order to make such corrections, the calculation results are output on a CRT screen as shown in FIG. 4, and a function is added to change the water supply amount on the screen using an input device such as a mouse. Change the water supply amount arbitrarily on the screen (for example, by moving blocks) and have the water level calculated again. These procedures are as shown in FIG. 2, and are executed by the computer 2.

That is, as shown in FIG. 2, demand forecasting (time series forecasting) is performed in step Sl, and then initial data such as initial water level, number of water pumps in operation, and storage time settings are manually entered (step 32). After inputting the initial data, the storage time water level (lower limit water level) is calculated in step S3, and thereby the storage time water level (upper limit water level) is calculated (step S4).

'' After calculating the second limit water level, the discharge amount of the water pump is calculated based on this (step S5). The water level of the distribution reservoir is calculated based on the calculated discharge amount of the water pump (step S
6) It is determined whether this water level calculation value is within the upper and lower water level limits (step 37).

If it is not within the range, the number of pumps in operation is changed (Step S8), and the operations of Steps S5 to S7 are repeated. If it is determined in step S7 that the water and sewerage levels are within the water level, it is determined whether or not the calculation for one day has been completed (step S9). If not, the process returns to step S5, and if it has been completed, the result is displayed (step S9). step SIO). Based on the result, it is determined whether or not correction is necessary (step S l 1),
If necessary, it is corrected (Step Nob SI2), and the water level is calculated based on this (Step S13). If there is no need for modification, create a water pump operation plan (step S14).
, the control device is operated (step Sl5). Therefore, while the controller controls the operation of the water pump, the operator station centrally monitors process data.

H. Effects of the Invention The present invention, as described above, calculates the storage water level for a predetermined time at an arbitrary time based on the demand forecast, and thereby determines the target water level of the water distribution reservoir. The target water level consists of a lower limit water level that is stored for a certain period of time and an upper limit water level that is calculated from the storage amount for a longer period of time. By planning the water pump operation so that the water level of the water distribution reservoir falls within the range of the target water level, the following effects can be obtained.

(1) The optimal amount of water is stored in the distribution reservoir according to the daily demand.

(2) Water can be delivered at an appropriate water level even when demand is low, reducing pump power costs.

(3) No matter when and at what time the water supply is stopped, the storage time is clear, which has the advantage of making it easier to take recovery measures.

Furthermore, by adding a correction function by the operator, (4) Reduce the frequency of starting and stopping the pump.

(5) Easy to formulate water supply plans according to changing conditions Other advantages are added.

[Brief explanation of drawings]

FIG. 1 is a block diagram of a water pump predictive operation control device according to an embodiment of the present invention, FIG. 2 is an operation flow diagram of the device in FIG. 1, and FIG. 3 is a water pump predictive operation control device according to an embodiment of the present invention. FIG. 4 is a time characteristic diagram of the flow rate and water level according to the apparatus, and FIG. 4 is a time characteristic diagram of the flow rate and water level according to the embodiment. 1... Operator station for monitoring operation, 2...
Operation management computer, 3...Data artery, 4a~
4d... Signal converter, 5a-5d... Local area network, 68-6d... Programmable controller, 7a-7c... Auxiliary relay board, 8... Pumping station, 9... Chemical injection Equipment, 1o...sedimentation pond. Two other people Figure 1: Point example Kuko; l! 1 operation ★Ura equipment diagram 2

Claims (1)

[Claims] (1) Calculate the amount of stored water for a predetermined time at any time from the demand forecast, set the water level determined based on the calculation result as the lower limit water level of the distribution reservoir, and set the water level for a period longer than the predetermined time at the arbitrary time a calculation means for planning the operation of a water supply pump for water storage so that the water level of the distribution reservoir falls within the upper limit water level range, with the water level determined from the amount of water stored in 1. A water pump predictive operation control device comprising a control means for switching the number of water pumps in operation according to the number of water pumps in operation.