JPH11353019A - Abnormal value detector - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a device capable of highly accurately detecting the abnormality of a measuring instrument. SOLUTION: This device is provided with a measured value storage device 5 for storing measured values outputted from various kinds of basic measuring instruments installed in the respective processes of a plant, a tread abnormality detector 6 for detecting the abnormality of trend based on data in the measured value storage device 5, and a display device 8 for displaying the result from the trend abnormality detector. Further, this device is provided with at least one auxiliary measuring instrument installed in at least one process of the plant on the similar environmental condition of the same kind as the basic measuring instrument, a second trend abnormality detector 62 having the same function as the trend abnormality detector 61 for operating data from the auxiliary measuring instrument through the measured value storage device, and a trend abnormal value discriminating device 7 for discriminating trend abnormality by operating outputs from two trend abnormality detectors 61 and 62.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an abnormality detecting apparatus for detecting an abnormality of a measuring instrument used in a plant such as a water and sewage treatment apparatus.

[0002]

2. Description of the Related Art Conventionally, in a plant such as a sewage treatment system, a large number of measuring instruments installed in the plant are monitored in a central monitoring room. When an abnormality occurs in each measuring instrument, for example, as shown in FIG. There is an apparatus which detects an abnormality of a measuring instrument using such an apparatus (Japanese Patent Application Laid-Open No. 9-33537). FIG. 3 is a block diagram showing an abnormality detection system using an abnormality detection device of a measuring instrument in a sewage treatment plant. That is, the sewage introduced from the water channel 1 is first discharged through the sedimentation basin 2, the aeration tank 3, and the final sedimentation basin 4. In this system, data from a group of various measuring instruments arranged during this time is accumulated in a measured value accumulating device 5, calculated by a trend abnormality detecting device 6, and the result is displayed on a display device 8. In addition,
The trend refers to a movement in which the measuring device becomes dirty and the measured value rises or falls in a certain direction.

[0003] First, in the sedimentation basin 2, sediment that tends to settle out of the sewage pollutants is settled and separated, and the supernatant water flows out to the aeration tank 3. In the aeration tank 3, returned sludge extracted from the final sedimentation basin 4 is returned through the water channel 22, and air blown from a blower (not shown) is supplied into the aeration tank 3 from a diffuser pipe (not shown). The polluted substances are adsorbed and decomposed by the activated sludge and led to the final sedimentation basin 4. Final sedimentation basin 4
Then, the activated sludge is settled and separated, and the clarified water is discharged as treated water from a water channel 23 through a sterilization tank (not shown), and the settled sludge is returned to the aeration tank 3, and a part of the sludge is treated in the sludge treatment process (shown in FIG. To be processed.

[0004] The measuring instrument group consists of the following. That is, 9 is an inflow sewage flow meter, 10 is an inflow water pH meter, 11
Is the suspended solids concentration meter of the inflow water, and 12 is the UV of the inflow water of the aeration tank
13, dissolved oxygen concentration meter (DO meter), 14 is MLSS
Concentration meter, 15 is a water temperature meter, 16 is an oxidation-reduction potentiometer, 17 is a pH meter of treated water, 18 is a suspended matter concentration meter of treated water, 19
Is a UV meter for treated water. The trend abnormality detection device 6 includes a daily average value calculation device, a change amount calculation device, a determination reference value storage device, a trend determination calculation device, a trend abnormal value continuous counting device, an abnormal number determination reference value storage device, and a trend number determination device. . As a result of the calculation, when the trend count determining device compares the value output by the trend determining calculating device with the reference value stored in the abnormality count determining reference value storage device and the value of the trend calculating device exceeds the reference value. Output an error.

[0005]

In the conventional measuring instrument abnormality detecting apparatus, the trend abnormality is detected using only the related measuring instruments. However, there is a case where the measured value unilaterally increases or decreases due to a change in the conventional operation or the like.
In such a case, even if the measuring device is operating normally, the measured value unilaterally increases or decreases, so that an inappropriate determination of outputting a measurement value abnormality due to a trend has been made. The present invention provides an apparatus that can automatically check whether or not a measuring instrument is operating normally by considering the operation of the measuring instrument that is assumed to perform the same operation as the related measuring instrument.

[0006]

According to the present invention, there is provided a measurement value accumulating device for accumulating measurement values output from various basic measuring instruments installed in each step of a plant; An abnormal value that includes a trend abnormality detection device that detects a trend abnormality based on data of a storage device, and a display device that displays a result from the trend abnormality detection device, and that detects an abnormality in a measurement value of the measuring instrument group. In the detection device, at least one measuring device of the same type as the basic measuring device is used in at least one process of the plant under similar environmental conditions.
And a second trend abnormality detecting device that calculates data from the auxiliary measuring device via the measured value accumulating device and has the same function as the first trend abnormality detecting device. And a trend abnormality value determination device that calculates outputs from the two trend abnormality detection devices to determine a trend abnormality. Further, the two trend abnormality detection devices, a daily average value calculation device that calculates a daily average value of the measurement values stored in the measurement value storage device, and a change amount calculation device that calculates the change amount of the daily average value, A criterion value storage device storing a criterion value for determining the upper and lower limits of the amount of change in the daily average value, and determining whether the amount of change in the daily average value has exceeded the criterion value of the same sign as the last few days. A trend determination calculating device for calculating, a trend abnormal value continuous counting device for calculating whether the daily average value continuously exceeds a determination reference value, and an abnormality storing a determination reference value of the trend abnormal value continuous count determining device. It comprises a number-of-times determination reference value storage device and a trend number determination device that determines whether the value of the trend abnormal value continuous counting device has exceeded the value of the number-of-abnormalities determination reference value storage device.
Further, the plant is a sewage treatment plant, the process is an aeration tank, and the auxiliary measuring device is an MLSS concentration meter.

[0007] Since the above-described means makes the determination including the operation of the similar measuring instrument, it becomes possible to know whether all the related measured values have changed due to the change in operation or whether the measuring instrument is abnormal. The accuracy of detecting abnormality of the measuring instrument is improved.

[0008]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Embodiments of the present invention will be described below in detail with reference to the drawings. FIG. 1 is a block diagram of a sewage treatment system using the abnormality detection device of the present invention. In the figure, reference numerals 20 and 21 denote an MLSS concentration meter and an oxidation-reduction potentiometer which are auxiliary measuring devices. The MLSS densitometer 20 and the oxidation-reduction potentiometer 21 are installed in the aeration tank 3 in a waterway branched from the sedimentation basin 2 first. Reference numeral 5 denotes a measured value storage device. Reference numeral 6 denotes a trend abnormality detection device for detecting a movement in which the measurement device is stained and the measured value rises or falls in a certain direction. Consists of Reference numeral 7 denotes a trend abnormal value determination device. The difference from the conventional system is that
The point is that the auxiliary measuring device, the second trend abnormality detection device 62 and the trend abnormality value determination device 7 are used.

FIG. 2 is a block diagram showing a detailed function of the trend abnormality detecting device 6. The first trend abnormality detecting device 61 calculates data from a group of measuring instruments via the measured value accumulating device 5 by the following devices. That is, the daily average value calculation device 611, the daily average value change amount calculation device 612, the determination reference value storage device 613, the trend determination calculation device 614, the trend abnormal value continuous counting device 615,
It comprises an abnormal number determination reference value storage device 616 and a trend number determination device 617. Second trend abnormality detection device 62
Also has a function similar to that of the first trend abnormality detecting device 61, and the data from the auxiliary measuring instrument group is calculated by each device via the measured value accumulating device 5. The reference numerals of the respective devices are 621, 622, 623, 624, 62, respectively.
5, 626, and 627.

The daily average value calculating devices 611 and 621 are based on the assumption that the data cycle of the sewage treatment process is mainly 24 hours, and calculate the past daily average value in order to handle the data on a daily basis. is there. Daily average change calculation device 61
Reference numerals 2 and 622 calculate the amount of change in the past daily average calculated by the daily average calculators 611 and 621, respectively. The criterion value storage devices 613 and 623 store the criterion values for the amount of change in the daily average value. Trend judgment arithmetic unit 6
14 and 624 determine whether or not the change amount of the daily average value calculated by the change amount calculation device 612 exceeds the judgment reference value stored in the judgment reference value storage devices 613 and 623.
The trend abnormal value continuous counting devices 615 and 625 determine that an abnormality occurs when the amount of change in the daily average value continuously exceeds the same value (upper limit value, lower limit value) stored in the determination reference value storage devices 613 and 623. The number of times of determination is stored. The trend number determining devices 617 and 627 are the trend determination calculating device 61
The values output in steps 4 and 624 are compared with the reference values stored in the reference value storage devices 616 and 626, and if the value of the trend calculation device exceeds the reference value, an abnormality is output. The trend abnormal value determination device 7 of the similar measuring device checks and determines the results output by the trend number determination devices 617 and 627.

Next, the operation will be described. Now, the MLSS concentration meter 14 of the basic measuring instrument installed in the aeration tank 3 is used.
, And a trend occurs in which the measured value rises in a certain direction. Then, the first trend abnormality detecting device 61 calculates the trend data via the measured value accumulating device 5 and sends it to the trend abnormal value determining device 7. On the other hand, since the MLSS concentration meter 20, which is an auxiliary measuring device installed in a water channel branched from the aeration tank 3, is operating normally, normal data is calculated by the trend abnormality detecting device 62 via the measured value accumulating device 5. Trend abnormal value judgment device 7
Sent to In the trend abnormal value determination device 7, since there is a difference between the MLSS densitometer 14 as the basic measuring device and the MLSS densitometer 20 as the auxiliary measuring device, it is judged as abnormal and the result is displayed on the display device 8. Further, the oxidation-reduction potentiometer 16 of the basic measuring device can detect an abnormality in the same manner as the above-mentioned MLSS concentration meter. Next, when the operating condition of the sewage treatment system is changed and the quality of the inflow water flowing from the water channel 1 changes, the data from the basic measuring device and the data from the auxiliary measuring device change in the same manner. In addition, it does not recognize that the measurement device is abnormal, and does not display the abnormality on the display device 8. In this way, if both the basic and auxiliary instruments are normal, it is normal, if any of the instruments has a trend, and if both instruments output an error, the plant operating conditions Normal is output assuming that the water quality has changed due to the change. In addition,
In the present embodiment, two types of measuring devices, an MLSS concentration meter and an oxidation-reduction potentiometer, are used as auxiliary measuring devices. However, the present invention is not limited to this, and one auxiliary measuring device may be used in one process. The abnormality of the measuring instrument can be detected even if a plurality of the measuring instruments are used in the step.

[0012]

As described above, according to the present invention, the auxiliary measuring device, the second trend abnormality detecting device and the trend abnormal value judging device are added, so that the operating conditions can be changed or the sensor unit can accumulate dirt. Accordingly, it is possible to cope with an abnormality of the measuring device when the measured value unilaterally increases or decreases, and there is an effect that the accuracy of detecting the abnormality of the measuring device is improved.

[Brief description of the drawings]

FIG. 1 is a block diagram showing a sewage treatment system using the abnormality detection device of the present invention.

FIG. 2 is a block diagram showing a detailed function of the trend abnormality detection device shown in FIG.

FIG. 3 is a block diagram showing a sewage treatment system using a conventional abnormality detection device.

[Description of Signs] 1, 22, 23: Waterway 2: First settling basin 3: Aeration tank 4: Final settling basin 5: Measurement value storage device 6: Trend abnormality detection device 61: First trend abnormality detection device 62: No. Second trend abnormality detecting devices 611, 621: daily average value computing device 612, 622: change amount computing device 613, 623: judgment reference value storage device 614, 624: trend decision computing device 615, 625: trend abnormal value continuous counting device 616, 626: Abnormal frequency judgment reference value storage device 617, 627: Trend frequency judging device 7: Similar measuring device Trend abnormal value judging device 8: Display device 9: Inflow sewage flow meter 10: Inflow water pH meter 11: Inflow water 12: UV meter for influent of aeration tank 13: Dissolved oxygen meter 14, 20: MLSS meter 15: Water temperature meter 16, 21: Redox Position meter 17: pH of the treated water meter 18: treated water turbidity meter 19: UV meter treated water

Claims (5)

[Claims] 1. A measurement value accumulating device for accumulating measurement values output from various basic measuring instruments installed in each process of a plant, and a trend detecting a trend abnormality based on data of the measurement value accumulating device. An abnormality detection device, comprising: a display device that displays a result from the trend abnormality detection device; and an abnormality value detection device that detects an abnormality of a measurement value of the measuring device group. An auxiliary measuring device in which at least one measuring device of the same type as the measuring device is installed under similar environmental conditions; a data from the auxiliary measuring device is calculated via the measurement value accumulating device; and the trend abnormality detecting device is a first. A second trend abnormality detection device having the same function as above, and a trend abnormality value determination device for calculating an output from the two trend abnormality detection devices to determine a trend abnormality. Outlier detection apparatus characterized in that a and. 2. The apparatus according to claim 1, wherein the two trend abnormality detection devices include a daily average value calculating device that calculates a daily average value of the measured values stored in the measured value storage device, and a change amount that calculates a change amount of the daily average value. An arithmetic unit, a criterion value storage device storing a criterion value for determining the upper and lower limits of the change amount of the daily average value, and a change amount of the daily average value exceeding a criterion value of the same sign as the last several days A trend determination calculation device for calculating whether or not
A trend abnormal value continuous counting device that calculates whether the daily average value has continuously exceeded a determination reference value, and an abnormal number determination reference value storage device that stores a determination reference value of the trend abnormal value continuous count determination device, 2. The abnormal value detecting device according to claim 1, further comprising a trend number determining device that determines whether a value of the trend abnormal value continuous counting device exceeds a value of the abnormal number determination reference value storage device. 3. The plant is a sewage treatment plant, and
The abnormal value detection device according to claim 1 or 2, wherein the step is an aeration tank. 4. The abnormal value detecting device according to claim 3, wherein said auxiliary measuring device is an MLSS densitometer. 5. The abnormal value detecting device according to claim 3, wherein said one step is a water channel branched in parallel, and said auxiliary measuring device is installed in said water channel.