JPH07325617A - Abnormality detecting device - Google Patents

Abstract

PURPOSE:To improve the operation rate of a thermal plant such as a refrigeration plant by accurately detecting an abnormal state of the plant and preventing the unnecessary operation correction, stop, and abnormality inspection of the plant due to an erroneous transmission of an abnormality alarm. CONSTITUTION:This abnormality detecting device is equipped with a data collection device 21 to which detection data (detected state quantity) on the state quantity of the plant are inputted and a probability totalizing arithmetic unit 25 which compares with the detected state quantity with a reference state quantity value, calculates the probability that the state quantity enters a dangerous state from the time and frequency where the detected state quantity is on a dangerous area side about the reference value and the probability that the state quantity enters a dangerous state, and generates an alarm when the arithmetic result exceeds a specific degree of danger.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION The present invention detects a state quantity such as temperature, pressure, flow rate, etc. of a variety of plants such as a refrigerating plant and a heat recovery plant when it is in a dangerous region and changes the operating condition of the plant by issuing an alarm. The present invention relates to an abnormality detection device configured to make a stop.

In a plant that mainly performs a heat cycle, such as a refrigerating plant and a heat recovery plant, when the state quantities such as temperature, pressure and flow rate of a refrigerant and a heat medium flowing through the plant exceed predetermined reference values, Is detected and transmitted to an alarm device, and an alarm is issued to change the operating condition of the plant away from the dangerous area, or the plant is stopped.

As an example of such an abnormality detection system, the invention of Japanese Patent Laid-Open No. 5-272849 has been proposed. In the present invention, the measurement data indicating the operating state of the heat exchanger is measured, the generated heat amount and the supplied heat amount are obtained based on the measured data, and the coefficient of performance of the heat exchanger is calculated from the generated heat amount and the supplied heat amount. , The correlation between the measurement data is obtained based on the measurement data, and the annual maximum / minimum value of the coefficient of performance and the average value thereof and the correlation between the measurement data are displayed, and the heat exchanger is analyzed from the fluctuation tendency. The deterioration is predicted. In such a method, in the heat exchanger and its peripheral equipment, such as a refrigeration compressor,
The relationship with the preset alarm set value is unclear, and it will be necessary to detect abnormalities from the viewpoint of ensuring safe driving.

[0004]

In a plant provided with an alarm set value indicating a dangerous area, an alarm level of 2-3 levels such as a light alarm and a heavy alarm is set, and for example, a light alarm is a heavy alarm. However, when there is an abnormality in the plant, it often leads to a heavy alarm that stops the plant in a short time. However, if the abnormality is mild, it often returns to the safe area naturally within a relatively short time. In addition, in complex plants that have been increasing in recent years, a minor abnormality of the plant is often amplified due to the relationship with other devices.

However, even when the state quantity temporarily exceeds the reference value as described above, it is generally overwhelming that the plant is normally operated with the state quantity below the reference value. There are many. However, even when only such a minor abnormality occurs, if the warning is issued by the entry of the temporary state quantity into the dangerous area as described above, the operating state of the plant is removed from the desired state. It has to be corrected, or the plant must be stopped to check for abnormalities and complicated start-up operations must be performed, which reduces the operating rate of the plant.

An object of the present invention is to accurately detect an abnormal state of a plant, to prevent the occurrence of situations such as unnecessary operation correction, stop and abnormal inspection of the plant due to erroneous transmission of an abnormal alarm, and the operating rate of the plant. It is also possible to improve the maintenance by enabling the planned adjustment of the equipment.

[0007]

Taking a heat cycle plant, particularly a refrigeration plant as an example, two heat exchangers consisting of a compressor, a condenser and an evaporator, equipment such as an expansion valve are abnormal, and this occurs. It appears as a pressure change or temperature change of the refrigerant or the fluid to be cooled, and even if these state quantities temporarily exceed a certain allowable value (value immediately before entering the dangerous area), that is, a reference value, In combination with the fact that the reference value is given as an upper limit value for ensuring safety or high-efficiency operation in equipment design, it cannot be concluded that an abnormality has occurred in this plant equipment.

According to the present invention, in order to detect that a true abnormality has occurred in the plant equipment, the transition of the probability that the state quantity exceeds the reference value is obtained, and when this probability increases. It is configured to determine that an abnormality has occurred in the device, and the detection data of the state quantity (detected state quantity)
Is compared with the data acquisition device to which the detected state quantity and the reference value of the state quantity are compared, and the state quantity is dangerous from the frequency such as the time and the number of times that the detected state quantity is on the dangerous side of the reference value. The present invention is characterized by including a probability / total calculation device that calculates a probability of being in a state and issues an alarm when the calculation result exceeds a predetermined risk level.

[0009]

[Function] In a refrigeration plant / heat recovery plant, the case where the detected value of the state quantity such as pressure and temperature exceeds the corresponding allowable value, that is, the reference value is detected, and the frequency per unit time and the generation time are calculated. If so, it can be used as a determination element for detecting an abnormality in the plant component equipment.

In the present invention, the difference between the detected value of the state quantity and the reference value is calculated and the trend of the difference is calculated. Then, in the probability / aggregation calculation device, the probability that the detected value exceeds the reference value is the frequency (number of times) occurring in a unit time,
It is obtained by integrating the occurrence times, etc., and when this probability increases, it is determined that an abnormality has occurred in the device, this is displayed on the display device, and an alarm as an abnormality detection signal is issued.

[0011]

Embodiments of the present invention will now be illustratively described in detail with reference to the drawings. However, unless otherwise specified, the dimensions, materials, shapes, relative positions, etc. of the structural components described in this embodiment are not intended to limit the scope of the present invention thereto, but are merely illustrative examples. Nothing more than.

1 and 2 are a system diagram and a block diagram of an abnormality detection device for a refrigeration system according to an embodiment of the present invention. 1 and 2, 1 is a compressor of a refrigeration system, 2
Is a condenser, 3 is an evaporator, 4 is an expansion valve, 5a and 5b are gaseous refrigerant lines, 6 is a liquid refrigerant line, 7 is a cooled fluid line,
Reference numeral 8 denotes a cooling fluid pipe, which constitutes a known refrigeration cycle by the above-mentioned equipment elements.

Reference numerals 9 and 10 are a pressure detector and a temperature detector attached to each device of the refrigeration cycle. Reference numeral 20 denotes an abnormality detection device, which includes a data acquisition device 21 and a state quantity determination device 2
4, a reference value setting device 23 and a probability / aggregation calculation device 25. Reference numeral 31 is a display device for displaying an output signal from the probability / total calculation device 25.

The data acquisition device 21 in the abnormality detection device 20 detects the instantaneous pressure and temperature of each device of the refrigeration system input from the pressure detector 9 and the temperature detector 10 attached to each device of the refrigeration system. The detection signal data is received and stored. The detection signal includes not only the pressure and temperature but also state quantities such as power and flow rate.

The reference value setting device 23 sets a reference value corresponding to the pressure and temperature detection signals from each device of the refrigeration cycle shown in FIG. This reference value is a value immediately before the state quantity such as pressure and temperature of the equipment in the refrigeration cycle enters the dangerous range, that is, an allowable value.

The state quantity measuring device 24 calculates the difference between the detection signal of the pressure, temperature, etc. and a reference value, and each detection signal data is in the "+" direction with respect to the reference value (direction entering the danger zone).
Alternatively, it is to determine at which point in the “−” direction (direction not reaching the dangerous area).

The probability / aggregation calculation unit 25 determines whether the detected value exceeds the reference value and the number of times it does not exceed the reference value based on the trend of pressure and temperature deviations output from the state quantity determination unit 24. The probability of exceeding the standard value is calculated from the changes in the total value when the detected value exceeds the standard value, and the abnormality of the device is determined from the degree of increase of this probability. C. Divide the detected value into areas of appropriate temperature range or pressure range and total the number of appearances in each range to form a histogram. Fit a statistical distribution curve such as the positive distribution of the form closest to this. The probability of exceeding the reference value is obtained from this distribution curve, and the abnormality of the device is determined from the degree of increase of this probability. The probability becomes zero when the standard values are not exceeded in the methods a and b, but even in such a case, the risk probability in the statistical sense can be obtained by the method c.

Next, the operation of the refrigeration system abnormality detecting device will be described. The detection signal data of the pressure and temperature of the refrigerant, the fluid to be cooled, the cooling fluid, etc. detected by the pressure detector 9 and the temperature detector 10 attached to each device of the refrigeration cycle are the data of the abnormality detection device 20 every moment. Acquisition device 21
Is input to and stored in.

The pressure and temperature detected by the detector are as follows. Condenser inlet / outlet refrigerant pressure and temperature Condenser inlet / outlet cooling fluid pressure and temperature Evaporator inlet / outlet refrigerant pressure and temperature Evaporator inlet / outlet cooled fluid pressure and temperature

The pressure and temperature detection signal data once collected in the data acquisition device 21 are input to the state quantity determination device 24. In the state quantity determination device 24, the deviation between the detection signal data of the pressure and the temperature and the reference value (allowable value immediately before entering the dangerous area) corresponding to the detection signal data input from the reference value setting device 23 is calculated. Further, the probability is calculated by determining which point is located on the dangerous area side or on the side away from the dangerous area with respect to the reference value.
Output to the total calculation device.

In the probability / total calculation device 25, the following method is used based on the difference between the detected state quantity such as the detected pressure and the detected temperature calculated by the state quantity judgment device 24 and the corresponding reference value. It is determined whether or not the state quantities such as pressure and temperature of each device are in the dangerous area.

(1) When the increase rate of the probability obtained by the above-mentioned methods A to C increases within a predetermined time, that is, when the probability that the detected value exceeds the reference value increases, the device concerned is It is determined that an abnormality has occurred, the determination result is output to the display device 31, and an alarm is issued.

(2) A trend graph in which the difference between the detected value of the state quantity and the reference value is plotted is prepared, and the detected value is displayed in a unit of a predetermined period such as a unit of a day, a unit of a week or a unit of a month. The probability of exceeding the reference value is obtained, and when this probability tends to increase, it is determined that an abnormality has occurred in the device, is displayed on the display device 31, and an alarm is issued.

(3) The time when the detected value exceeds the reference value is obtained from the trend diagram, and the measured time is compared with a predetermined allowable time, and the probability that the measured time is longer than the allowable time tends to increase. When it becomes, it is determined that an abnormality has occurred in the device, this is displayed on the display device 31, and an alarm is issued.

[0025]

As described above, according to the present invention, the difference between the detected value of the state quantity such as the pressure and temperature of the plant constituent equipment and the reference value which is the allowable value thereof is calculated every moment and the trend of the trend is calculated. Calculate the probability that the detected value exceeds the reference value, such as the number of times per unit time that the detected value exceeds the reference value, or the time that the detected value exceeds the reference value, and detect the device abnormality based on this probability. Since it is configured as described above, even if there is no abnormality in the device as in the conventional method, an alarm is not issued and the abnormality of the device can be accurately detected.

As a result, it is possible to prevent the plant operation rate from being lowered due to the unnecessary inspection of abnormalities, and it is possible to systematically adjust the equipment to improve the maintainability.

[Brief description of drawings]

FIG. 1 is a system diagram of a refrigeration cycle according to an embodiment of the present invention.

FIG. 2 is a control block diagram in the refrigeration cycle.

[Explanation of symbols]

 1 Compressor 2 Condenser 3 Evaporator 4 Expansion valve 9 Pressure detector 10 Temperature detector 20 Abnormality detection device 21 Data acquisition device 23 Reference value setting device 24 State quantity determination device 25 Probability / aggregation calculation device 31 Display device

Claims (1)

[Claims] 1. An abnormality detection system configured to issue an alarm when a state quantity such as pressure or temperature of various plants such as a refrigerating plant or a heat plant enters a dangerous area, wherein detection data (detection state) of the state quantity is detected. (Amount) input and stored in the data acquisition device, and the detected state quantity and the reference value of the state quantity are compared, and the detected state quantity is in the dangerous area side from the reference value. An abnormality detection device, comprising: a probability / aggregation calculation device that calculates a probability of a dangerous state and issues an alarm when the calculation result exceeds a predetermined risk level.