JP5454950B2 - Plant monitoring and control system - Google Patents

Description

  Embodiments of the present invention relate to a plant monitoring control system used for a control system of a waterworks plant, for example.

  In recent years, water supply facilities (hereinafter referred to as water supply plants) are required to realize a highly reliable water distribution system against piping breakage accidents and the like. Therefore, a water supply plant has been implemented in which a network of water transmission and distribution pipes is constructed to make the water distribution system redundant. In this type of system, high reliability can be obtained for disasters such as earthquakes and unexpected piping accidents, but there are also cases where simultaneous transmission and distribution of multiple systems and reception of water are difficult. In such a case, water that has been subjected to purified water treatment as drinking water may stagnate in the pipe for a long time, leading to a decrease in residual chlorine concentration.

  The dilemma of improving reliability and reducing residual chlorine concentration due to redundancy in this way is not limited to water supply / distribution pipes connecting between stations, but also pipes in water supply / distribution stations (for example, pump pressure supply pipes and direct delivery pipes) ) Also occurs.

JP-A-6-299576

The residual chlorine concentration of purified water decreases due to stagnation for a long time. The degree of decrease in residual chlorine concentration is not constant, and mainly depends on environmental factors such as temperature and season. For this reason, the operator of the plant system has to determine whether or not to implement a countermeasure against stagnant water (circulation operation of water in the pipes), and the load is increasing.
An object of the present invention is to provide a plant monitoring and control system that can reduce the load on an operator without impairing reliability due to redundancy.

  According to the embodiment, the plant monitoring and control system is a system that monitors and controls a waterworks plant including a piping system that is redundantly provided with a regular piping and a standby piping. The plant monitoring and control system compares the measured value with a predetermined reference value by measuring the residual chlorine concentration of water stagnating in the standby piping, and compares the measured value with a predetermined reference value. A determination unit that determines whether countermeasures are necessary, and a notification unit that notifies a result of the determination.

The figure which shows an example of the plant monitoring control system concerning 1st Embodiment. The figure which shows the flowchart which shows the process sequence of the necessity determination process of a stagnant water countermeasure in the plant monitoring control system shown by FIG. The figure which shows an example of the plant monitoring control system concerning 2nd Embodiment. The figure which shows an example of the plant monitoring control system concerning 3rd Embodiment. The figure which shows an example of the plant monitoring control system concerning 4th Embodiment.

[First Embodiment]
FIG. 1 is a diagram illustrating an example of a plant monitoring control system according to the first embodiment. The system shown in FIG. 1 monitors and controls a water supply plant having a piping system made redundant to a normal system pipe and a standby system pipe. In FIG. 1, it is assumed that the standby system pipe 10 is closed by a valve M and stagnant water is retained. The spare piping 10 is provided with a residual chlorine concentration measuring sensor 20 that measures the residual chlorine concentration of water in the spare piping 10 and obtains a measured value. The residual chlorine concentration measurement value is notified to the determination unit 40 of the stagnant water countermeasure control device 30 via, for example, a LAN (Local Area Network).

  The determination unit 40 compares the measured value of residual chlorine concentration with a predetermined reference value (management value), and determines the necessity of countermeasures against water stagnation in the standby piping based on the result. The determination result is sent to the notification unit 50 and announced (reported) to an operator (not shown).

  FIG. 2 is a flowchart illustrating a processing procedure of necessity determination processing for countermeasures against stagnant water in the plant monitoring control system illustrated in FIG. 1. Here, the management value, which is a reference value for determining whether or not stagnant water is necessary, is set in a plurality of stages (N stages), and management value 1> management value 2>.

  When the stagnant water necessity determination process is started in FIG. 2, the determination unit 40 compares the residual chlorine concentration measurement value with the minimum management value (management value 1) (step S1). If the measured value of residual chlorine concentration is larger than the control value 1 (Y in step S1), it is determined that a countermeasure for stagnant water of level 1 is required (step S2), and a report is issued to the operator.

  Next, the determination unit 40 compares the residual chlorine concentration measurement value with the second smallest management value (management value 2) (step S3). If the measured value of residual chlorine concentration is larger than the control value 2 (Y in step S3), it is determined that a countermeasure against stagnant water of level 2 is required (step S4), and a report is issued to the operator.

  The above procedure is repeated over N stages. That is, in step S5, the determination unit 40 compares the residual chlorine concentration measurement value with the maximum management value (management value N) (step S5). If the measured value of residual chlorine concentration becomes larger than the control value N (Y in step S5), it is determined that a countermeasure against stagnant water of level N is required (step S6), and a report is issued to the operator. As described above, the notification unit 50 performs notification at a level corresponding to a plurality of stages.

  As described above, in the first embodiment, the continuous measurement value of the residual chlorine concentration of the water stagnating in the standby piping 10 is input, and the stagnant water countermeasure is compared with a plurality of preset management values. The necessity determination (such as the circulation operation of water in the pipe) is performed, and stepwise determination results are generated and output along a plurality of management values.

  Thus, by announcing the necessity of countermeasures for stagnant water, the operator can be released from the work for determining whether or not countermeasures for stagnant water are necessary. In addition, by performing quantitative and continuous necessity determination processing by the system, it is possible to realize the optimal stagnation water countermeasure timing according to the season (water temperature) without depending on the operator's personal ability and experience. It becomes possible.

[Second Embodiment]
FIG. 3 is a diagram illustrating an example of a plant monitoring control system according to the second embodiment.

3, parts common to FIG. 1 are given the same reference numerals, and only different parts will be described here. In FIG. 3, the residual chlorine concentration measurement value from the residual chlorine concentration measurement sensor 20 is notified to the prediction unit 60 of the stagnant water countermeasure control device 30.

  The prediction unit 60 fits a plurality of time-series data of residual chlorine concentration measurement values to a predetermined mathematical model, and predicts the time that elapses until the residual chlorine concentration reaches the control value based on the result. That is, the prediction unit 60 performs model fitting using sampling data of residual chlorine concentration, and predicts the time required for the residual chlorine concentration to decrease from the current measured value to the control value.

Generally, the residual chlorine concentration C (t) after a certain time t is expressed by the following equation (1).
C (t) = Co × exp (−kt) (1)
In Equation (1), Co is an initial value of the residual chlorine concentration, and k is a rate constant for decreasing the residual chlorine concentration. As shown in equation (1), the residual chlorine concentration decreases exponentially with the elapsed time. Therefore, in the second embodiment, the decreasing tendency (concentration decreasing rate coefficient) is obtained by model fitting, so that the decreasing tendency of the residual chlorine concentration is estimated more precisely.

  By transforming equation (1) into an equation solved for k and applying the residual chlorine concentration after a certain time as sampling data (model fitting), the value of k depending on temperature or the like can be obtained. Next, the residual chlorine concentration management value is obtained by transforming equation (1) into an equation solved for t and applying the previously obtained value of k, the current residual chlorine concentration measurement value, and the residual chlorine concentration management value. Elapsed time can be calculated. In this way, the prediction unit 60 calculates the elapsed time required for the residual chlorine concentration to decrease from the current measured value to the control value.

  This time calculation result is sent from the prediction unit 60 to the notification unit 50 and announced (reported) to the operator. Thus, according to the second embodiment, the time required for the residual chlorine concentration to reach the control value can be known in advance. That is, the operator can know in advance the decreasing tendency of the residual chlorine concentration and the prediction result (information indicating how many hours or how many days later the management value falls). Therefore, the burden on the operator can be further reduced.

[Third Embodiment]
FIG. 4 is a diagram illustrating an example of a plant monitoring control system according to the third embodiment.

4, parts that are the same as those in FIG. 3 are given the same reference numerals, and only different parts will be described here.
In FIG. 4, the monitoring control system 70 is notified of the necessity determination result of stagnant water measures determined by the determination unit 40 and the time calculation result calculated by the prediction unit 60. The supervisory control system 70 is used by an operator for daily operation, and includes a supervisory console (terminal) 80. The necessity determination result and the time calculation result are issued by the operator via the monitoring console (terminal) 80. Since it did in this way, the operator can confirm alerting | reporting in the monitoring console (terminal) 80 currently monitored at the time of daily operation, and can shift now to stagnant water countermeasure operation easily.

[Fourth Embodiment]
FIG. 5 is a diagram illustrating an example of a plant monitoring control system according to the fourth embodiment.

5, parts common to FIG. 4 are denoted by the same reference numerals, and only different parts will be described here.
In FIG. 5, the supervisory control system 70 that has received the necessity determination result and the time calculation result outputs a command to a control circuit (not shown) provided in equipment such as a valve and a pump based on these results. . In response to this, the control circuit automatically performs a predetermined stagnant water countermeasure operation (for example, the pump is operated after the valve is opened).

  As described above, in the fourth embodiment, the necessity determination result and the time calculation result are input to the monitoring control system 70 used by the operator for daily operation, and are reported from the monitoring console (terminal) or the like, and determined in advance. The stagnation water countermeasure operation was automatically implemented. Since it did in this way, the operator can not only confirm the report on the monitoring console (terminal) 80 monitored during daily operation, but can also automatically shift to stagnant water countermeasure operation. .

As described above, according to the first to fourth embodiments, there is provided a plant monitoring control system that reduces the load on the operator without impairing the reliability due to the redundancy of the water supply system provided with the spare system piping. be able to.
Although several embodiments of the present invention have been described, these embodiments are presented by way of example and are not intended to limit the scope of the invention. These novel embodiments can be implemented in various other forms, and various omissions, replacements, and changes can be made without departing from the scope of the invention. These embodiments and modifications thereof are included in the scope and gist of the invention, and are included in the invention described in the claims and the equivalents thereof.

  DESCRIPTION OF SYMBOLS 10 ... Preliminary system piping, 20 ... Residual chlorine concentration measurement sensor, 30 ... Stagnant water countermeasure control apparatus, 40 ... Determination part, 50 ... Notification part, 60 ... Prediction part, 70 ... Monitoring control system, 80 ... Monitoring console (terminal) ), M ... valve

Claims (5)

A plant monitoring and control system for monitoring and controlling a water supply plant having a redundant piping system for a normal system pipe and a standby system pipe,
A measurement unit that measures the residual chlorine concentration of water stagnating in the preliminary piping and obtains a measurement value;
A determination unit that compares the measured value with a predetermined reference value, and determines the necessity of measures against the stagnation based on the result,
A plant monitoring control system comprising: a notification unit that notifies the determination result. The reference value is set over a plurality of stages,
The plant monitoring control system according to claim 1, wherein the notification unit performs notification at a level corresponding to the stage. Furthermore, it comprises a prediction unit that predicts the time that elapses until the residual chlorine concentration reaches the reference value by fitting a plurality of time series data of the measurement values to a predetermined mathematical model,
The plant monitoring control system according to claim 1, wherein the notification unit notifies the predicted time. Furthermore, it has a monitoring operation terminal operated by an operator,
The plant monitoring control system according to claim 1, wherein the notification unit notifies the operator of the result of the determination via the monitoring operation terminal.   Further, the plant monitoring control system according to claim 3, wherein a predetermined stagnant water countermeasure operation is performed by outputting a command to equipment provided in the piping system based on the result of the determination and the predicted time.

Images