JPS60131495A - Diagnostic device for abnormality of detector - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a detector abnormality diagnosing device, and more particularly to a detector abnormality diagnosing device applicable to nuclear power plants and the like.

For example, a control/protection system for atomic capillaries is essential for improving the safety, reliability, controllability, etc. of batteries. Therefore, the sensor that serves as the input to the above system is a particularly important element, and by providing redundancy, it is possible to cope with an unexpected abnormality in sensor sensitivity. For this reason, two to four sensors of the same type are used for the same process measurement to provide redundancy and perform relative evaluation among them. For example, an example in the case of four sensors will be explained with reference to FIG. Collect data from each redundant sensor using 1oo.

Next, in step 101, the deviation between different sensors is determined, and in step 1o2, an evaluation given by the following equation (1) is performed.

1Vi−Vj'l<ε1 ・Curve/Curved surface・ (1) However, V: sensor output value, i'=j i=1~4, i=x~
4, ε1: Threshold.

If formula (1) holds true in all cases (there are 6 cases of total ζ with 4 sensors), all sensors are judged as normal 104, and if formula (1) does not hold true in 2 or more cases of the same sensor, then The sensor is determined to be abnormal 103.

In an actual plant, one sensor is selected from the remaining sensors excluding the abnormal sensor determined in this way. There are various methods for this, for example, calculating the average value of normal sensor values,
The sensor with the value closest to that value may be selected. The output of this sensor will be used in the control/maintenance system.The basic idea of conventional sensor static characteristic abnormality diagnosis is relative evaluation between redundant sensors, not absolute evaluation, as shown in Figure 1. . Therefore, the number of correct sensors is the same or less (in the case of 4 sensors, 2
(less than 1), it may be impossible to select or make the wrong selection, which may lead to a serious accident. Currently 2 out of 4
Although it is assumed that the probability that two or more abnormalities will occur at the same time is low, there is no guarantee that such abnormalities will not occur. Additionally, sensors in processes that do not have redundancy have the disadvantage of being unavoidable.

The present invention was proposed in view of the above circumstances, and its purpose is to improve the reliability and safety of nuclear power plants by An object of the present invention is to provide a detector abnormality detection device capable of early diagnosing abnormality in response of a detector (sensor).

The detector abnormality diagnosis device according to the present invention includes a means for finding another independent process that defines the process to be diagnosed, a means for setting a function type that defines the process to be diagnosed as a function of the independent process, and a state in which the plant has settled. 1. means for setting the function value calculated from the values of the independent process sensors to Xi; and calculating the deviation of the value of the process sensor to be diagnosed from the true value; It is characterized by comprising a means for dividing this deviation by the true value and diagnosing a sensor abnormality when the value is larger than a separately specified threshold value, and having redundancy for measuring the same process. When diagnosing an abnormality in the static characteristics of a sensor or a sensor without redundancy, use a setting signal created using a separate process independent of the sensor in the process being diagnosed, rather than a relative evaluation between redundancies. According to the present invention, abnormalities in the static response of the sensor can be diagnosed using absolute evaluation, thereby overcoming the drawbacks of the conventional method.

An embodiment of the present invention will be explained in detail with reference to the accompanying drawings. Figure 142 is a 70-chart diagram for explaining the configuration of an embodiment of the present invention.

In Fig. 2, No is the sensor, this and 3 A/D.
An analog signal transmission line 2 is connected to the converter. 4,5.
6 is data input in digital format, and input values are stored in a timely manner. 7 controls and operates the A/D converter 3 to convert the analog value into a digital value, and 09 electrically stores it at 8 to determine the return of 7 and 8. 1
0.11 is a data transfer circuit, and 12.13 is an arithmetic circuit. J4 judges the result of J3, 15 is a circuit that generates a time delay, and ole judges the result of 1.
7 and 18 are circuits for diagnosing the state of the input data based on the judgment result of 16. Note that 4 to J8 described above are composed of multiple electrical digital processing circuits. The operation of the embodiment of the present invention described above will be explained below. In FIG. input.

In addition, in 5, the sensor of the process to be diagnosed is specified. In 06, the value of the sensor for diagnosing the above process and the value of the sensor of the process necessary for diagnosing the process are specified by j9 at an appropriate sampling time T. A/D converter 3
sampled under the control of 7 via. The sampling value can be converted into dimensions according to the physical system of the process8.
It is stored in . Repeat steps 7 and 8 until the number of data required for the calculation of J3 is reached. At No. 0, a function corresponding to the process to be diagnosed is selected from among the many input function data. 6
Outputs the sensor value of the process specified in (11). Using the function determined in step 10, calculate all the function values in J2 using the value determined in step 11, output the target process value stored in step 8 as and 9, and use this value and the function value in step 12 to calculate the function value in step 13. All the differential coefficients are calculated, and in step 14, the absolute values of the two differential coefficients of J3 are compared with the threshold value. If either of the two is above the threshold, it returns to 7 via the dead time of 15.If both of them are below the threshold, it goes to 16,
The rate of change in the sensor value of the process to be diagnosed, with the function value of No. 12 being 1.0, is determined and compared with a threshold value. If it is below the threshold value, the sensor is diagnosed as normal at 17, and if it is above the threshold value, the sensor is abnormal.The rate of change is diagnosed as a percentage at 18. After this, go back to step 5 and repeat the diagnosis of other sensors.

Next, a specific example in which the detector abnormality diagnosis apparatus according to the present invention is applied to, for example, a PWR plant will be described.

For example, if the process sensor to be diagnosed is a pressurizer water level sensor, the color value indicated by the pressurizer water level sensor in the settled state of the plant will be the two coolant temperatures of the primary coolant, high and low. It is given as a function of the average value.

The water level of the pressurizer is controlled so as to maintain this function value. Therefore, the process sensor that is necessary for making decisions is the coolant temperature sensor 2.
The function data is the average temperature and the water level value of the pressurizer. In this manner, in step 4 of FIG. 2, different function data is initially given for each process to be diagnosed, equal to the number of processes to be diagnosed.

(Of course, in this process, the same function is
It is also possible to directly import this rice power into the plant. At this time, 10 to J2 in Figure 2 are unnecessary.
The function value of 2 will be sampled at 2) 0 As an example of another process, in the case of steam generator water level, the water level set point is given as a function of the turbine first stage pressure. The sampled value of the process sensor to be diagnosed and the value of the process sensor required for diagnosis are respectively E, ENl...EN
Let i denote the setting value Ere of the process sensor to be diagnosed.
f is given by the following equation.

Eref = fun (ENl, E, , -・-E
N, )・−(2) fun: Input function i: Required number of process sensors If the plant is not stabilized, there may be a transient large deviation between the set value and the erosion indicated by the process, Take the differential coefficient for the 1M edict of the state.

If both equations (3) and (4) satisfy the following conditions, it is considered to be a stable state.

A〈ε.

and ) ・・・・・・・・・・・・ (5) B〈ε2 ε, Niji threshold If the formula (5) is not satisfied, the plant is considered to be unsettled, and after a while, steps 7 to 13 are carried out. I'll return it. When the granometer is in a stable state, the value E of the process sensor to be diagnosed is considered to be its set value Eref.
Determine whether the sensor is normal or abnormal based on the deviation ratio from ref.0 However, ε3: Threshold If equation (6) holds, the sensor is judged to be normal; if not, the sensor is judged to be abnormal, and the gain error from normality is VX100%.・
......0 given by (7) As described above, according to the present invention, the normality and abnormality of sensor static characteristics were conventionally judged only by relative evaluation between redundant sensors, but this invention By performing absolute evaluation according to the present invention, it is possible to prevent erroneous diagnosis of sensor static characteristic abnormality and the deterioration of plant safety that leads to this, and it is also possible to prevent redundant G
Excellent effects such as being able to diagnose abnormalities in static characteristics of single-process sensors can also be achieved.

[Brief explanation of drawings]

FIG. 1 is a flowchart for explaining a conventional example, and FIG. 2 is a flowchart for explaining the configuration of an embodiment of the invention. l...sensor, 2...analog signal transmission line, 3...
・A/D converter, 4 to 6...Data input, ノ2゜1
3...Arithmetic circuit, 17.18...Diagnostic circuit. Takehiko Suzue, Patent Attorney, Representative of Demachijin Figure 1

Claims (1)

[Claims] means for finding other independent processes that define the process to be diagnosed; means for setting a function type that defines the process to be diagnosed as a function of the independent processes; and calculation from the values of independent process sensors when the plant is in a stable state. A means for determining the true value of the function value obtained by calculating the deviation from the true value of the value of the process sensor to be diagnosed, and converting this deviation into
1. A detector abnormality diagnosing device comprising means for diagnosing a sensor abnormality when a value divided by a value is larger than a separately defined threshold.