JP2647392B2 - Controller abnormality diagnosis method - Google Patents

Description

The present invention relates to a controller abnormality diagnosis method applied to, for example, a main water supply controller of a water supply control system of a PWR plant and other controllers.

[Prior Art] Generally, when determining an abnormality diagnosis method, it is necessary to pay attention to the following two items.

To detect an abnormality before the abnormality of the device to be diagnosed causes a great disturbance to the control target and switch to the standby system. This is a reference for determining the set value and the upper limit of the set time.

Avoid abnormal conditions other than controller failure caused by disturbances applied to the controlled object, noise superimposed on input signals, etc., and avoiding erroneous diagnosis and erroneous switching. This is the basis for determining the set value and the lower limit of the set time.

However, the abnormality diagnosis method of the water supply controller in the conventional water supply control system of the PWR plant is such that the abnormality diagnosis is performed by setting only one type of deviation set value and the set time for performing the abnormality diagnosis of the controller. Therefore, when the set level is set so that an abnormality can be detected for a sudden failure of the controller, the sudden failure can be detected without causing a large disturbance to the control target, and erroneous diagnosis and erroneous switching can be performed. Also does not occur. However, a slow failure does not cause a deviation in the controller output because the failure is gradual. For this reason, the detection of the failure is delayed, and a large disturbance is given to the control target. Therefore, if the set level of the abnormality diagnosis is set small to avoid this, it is possible to detect not only a sudden failure but also a slow failure without giving a large disturbance to the control target. However, if such a setting is made, abnormal conditions other than the failure of the controller are established due to disturbance applied to the control target, noise superimposed on the input signal, and the like, resulting in erroneous diagnosis and erroneous switching.

[Problems to be Solved by the Invention] As described above, in the conventional abnormality diagnosis method, the deviation set value and the set time, which are the conditions for the abnormality diagnosis, are one type, so that a sudden failure ( The problem is that it is not possible to cope with a wide range of abnormalities from a case where the control output signal suddenly rises or the signal change rate such as a step-up suddenly increases to a case where a slow failure occurs (the reverse case). was there.

Therefore, an object of the present invention is to detect an abnormality before an abnormality of a device to be diagnosed causes a large disturbance to a control target even if the controller failure is sudden or slow, and to avoid erroneous diagnosis and erroneous switching. It is an object of the present invention to provide a controller abnormality diagnosis method that can be performed.

[Means for Solving the Problems] The present invention has taken the following means in order to solve the above problems and achieve the object. That is, the control deviation between the output of the normally used controller and the output of the standby controller which has a control function equivalent to that of the regular controller and is used in place of the regular controller has a preset setting. When the value deviates by a predetermined set time, and the deviation between the control amount and the reference value, which is the control result of the service controller, deviates from a preset value by a preset time, the service controller In the diagnosis method for diagnosing abnormality, a first condition including a combination of a large set value and a short set time as a failure detection condition including the set value and the set time for each series corresponding to each of the deviation inputs. And a second condition consisting of a combination of a small set value and a long set time, and the sudden input of the service controller that satisfies the first condition is determined by the deviation input, and the deviation input is determined by: It is configured such that a slow failure of the service controller satisfying the second condition can be detected.

[Action] By taking such a means, the following action is exhibited. Two types of detection conditions, one for a sudden failure and one for a slow failure, are set as detection conditions consisting of a deviation set value and a set time for diagnosing controller abnormalities. Is detected under the first condition, and a slow failure is detected under the second condition.
Therefore, for a sudden failure that has a sudden effect on the control target, the set time is short, so that quick failure detection is possible, and since the deviation set value is large, erroneous diagnosis can be avoided. In addition, for a slow failure that does not suddenly affect the control target, the deviation set value is small, so that a highly sensitive failure detection can be performed, and since the set time is long, erroneous detection can be avoided. .

[Embodiment] Fig. 1 is a diagram showing an embodiment in which the present invention is applied to a controller abnormality diagnosis device of a PWR plant main water supply control system. In the figure, a service controller 11 to be diagnosed performs a control operation by inputting a process amount s10 and outputs a service controller output s.
11 is output. Where the process amount s10
Represents a feedwater flow rate, a steam flow rate, a steam generator (hereinafter referred to as SG water level), a turbine first stage pressure, and the like. In addition, service controller
In the control calculation of 11, the cascade control is performed using the feed water flow rate and the steam flow rate as the advance signal so that the SG water level matches the SG reference water level determined by the turbine first stage pressure proportional to the generator load. . On the other hand, the standby controller 12 receives the process amount s10 and
And outputs a standby controller output s12. The service controller output s11 and the standby controller output s12 are switched and selected by the switch 13, and are output as the controller output s13. This controller output s13 becomes the opening command of the valve that adjusts the feedwater flow rate,
It adjusts the water level. The process amount s10,
The service controller output s11 and the standby controller output s12 are
To enter. Here, an abnormality diagnosis calculation is performed, and when the service system controller 11 is diagnosed as abnormal, the switching signal s1
4 to switch 13 and controller output s13 to service controller output
Switching from s11 to standby controller output s12 is performed.

FIG. 2 is a diagram showing a specific configuration of the diagnostic device 14. As shown in the figure, the diagnostic device 14 has four comparison / determination devices 21, 22, 23, and 24.
And four timers 31, 32, 33, 34, and two OR circuits 41, 42
And one AND circuit 50. Comparison judgment unit 21
Is used to compare and determine the total value of the difference between the service controller output s11 and the standby controller output s21 with the deviation set value ε1, and to output the determination signal s31 through the timer 31 to increase the sudden failure controller output deviation. It has become. The comparison / determination unit 22 compares and determines the absolute value of the difference between the service system controller output s11 and the standby system controller output s12 with the deviation set value ε2. Is output. The deviation set value ε1 is equal to the deviation set value ε.
It is set larger than 2. Further, the comparison / determination unit 23 compares and determines the absolute value of the difference between the feed water flow rate and the steam flow rate with the deviation set value ε3, and outputs the determination signal s33 for increasing the flow deviation via the timer 33. Another comparator 24 compares and determines the absolute value of the difference between the SG water level and the SG water level reference value with the deviation set value ε4, and outputs it as a determination signal s34 for increasing the SG water level deviation via the timer 34. ing. The timers 31, 32, 33, and 34 have a predetermined set time set in advance, and the comparison / determination unit continues for the set time or more.
An output signal is generated when each determination signal is input from 21, 22, 23, and 24.

FIG. 3 is a diagram showing the function of the timer. In the figure, A is an input signal from the comparators 21 to 24, and B is a timer output signal. As shown, when the input signal exceeds the set time T of the timers 31 to 34, the timer output becomes "1". The set time T of the above timer is slower than the set time T1 of the sudden failure timer 31.
The set time T2 of 32 is set to a better time. This is because the controller output deviation does not easily occur in the case of a slow controller failure, so it is necessary to reduce the deviation setting value, and increasing the setting time increases the possibility of erroneous diagnosis that increases by reducing the deviation setting value. In order to avoid this.

Returning to FIG. The OR circuit 41 receives the judgment signal s31 output from the timer 31 and the judgment signal s32 output from the timer 32, performs an OR operation, and outputs the result as a signal s41 having a large controller output deviation. . The OR circuit 42 inputs the determination signal s33 output from the timer 33 and the determination signal s34 output from the timer 34,
The logical sum is output as a signal s42 having a large process deviation. Further, the AND circuit 50 is connected to the OR circuits 41 and 42.
The outputs s41 and s42 are input, ANDed and the switching signal s
It is output as 41.

Next, the operation of the controller abnormality diagnosing device thus configured will be described. First, the working system controller 11 and the standby system controller 12 that have input the process amount s10 output the working system controller output s11 and the standby system controller output s12 to the switch 13, and also output to the diagnostic device 14. . At the same time, the process amount s10 is input to the diagnostic device 14. Diagnostic device 1
Service controller output s11 and standby controller output input to 4
The absolute value of the difference from s12 is compared and determined by the comparators 21 and 22 with the deviation set values ε1 and ε2, respectively, and after a lapse of time set by the timers 31 and 32, the sudden failure controller output deviation large judgment signal. It is determined whether or not s31 and the slow fault controller output deviation large judgment signal s32 are output. Then, if any one of the determination signals s31 or s32 is output, a signal s41 indicating that a controller output deviation large condition, which is a deviation condition, is satisfied via the OR circuit 41 is obtained.
An abnormality in the controller is detected.

On the other hand, the process amount s10 input to the diagnostic device 14 is compared with the flow rate large signal by the comparators 23 and 24 and the timers 33 and 34.
s33 and the SG water level deviation large signal S34 are output. The deviation set value ε3 of the flow rate deviation large signal S33, the set time of the timer 33 and the deviation set value ε4 of the SG water level deviation large signal s34, and the set time of the timer 34 have a small effect on the plant and no erroneous diagnosis. It is decided on condition. And large deviation signal s33 or SG water level deviation large signal s
If any one of the signals 34 is input to the OR circuit 58, a large process deviation signal s42 is output. The large flow rate deviation signal s33 and the large SG water level deviation signal s34 have an essential difference in the process amount, and the integral of the deviation between the feed water flow rate and the steam flow rate is the SG water level deviation.
For this reason, a sudden failure will cause a large flow deviation large signal s33
And a slow failure is detected by an SG water level deviation large signal s34 indicating accumulation of deviation. And the controller output deviation signal s41 and the process deviation signal s42 are AND circuit 5
When input to 0, the logical product is obtained and the switching signal s14 is generated. This switching signal s14 is given to the switch 13. As a result, the switch 13 receives the switching signal s14 and switches the signal path from the service controller 11 to the standby controller 12.

As described above, in the present embodiment, the first condition for a sudden failure and the second condition for a slow failure are detected as detection conditions including a deviation set value and a set time for diagnosing abnormality of the controller. And two types are set. In the case of a sudden failure, the influence on the control target is sharp, so the detection is performed under the first condition in which the set time T1 is shortened and the deviation set value ε1 is increased. In order to increase the disturbance gradually, the detection is performed under the second condition in which the deviation set value ε1 is made small and the set time T2 is made long. Therefore, it is possible to quickly detect a controller failure over a wide range from a sudden failure to a slow failure without causing a large disturbance to a control target,
Moreover, erroneous diagnosis and erroneous switching can be reduced.

It should be noted that the present invention is not limited to the above-described embodiment, and it is needless to say that various modifications can be made without departing from the scope of the invention.

[Effects of the Invention] According to the present invention, two types of deviation set values and set times for diagnosing abnormality of a controller are set for a sudden failure and a slow failure. Slight failures are detected under the first condition, and slow failures are detected under the second condition. Therefore, for a sudden failure that suddenly affects the control target, the set time is short, so that quick failure detection is possible, and the error set value is large, so that error diagnosis can be avoided. In addition, for a slow failure that does not suddenly affect the control target, the deviation set value is small, so that a highly sensitive failure detection can be performed, and since the set time is long, erroneous detection can be avoided. . Thus, even if the controller malfunctions rapidly or slowly, the controller abnormality diagnosis can detect the abnormality before the abnormality of the device to be diagnosed causes a large disturbance to the control target, and can avoid erroneous diagnosis and erroneous switching. A scheme can be provided.

[Brief description of the drawings]

FIG. 1 is a diagram showing a configuration of an abnormality diagnosis device in which the present invention is applied to a main water supply control system of a PWR plant, FIG. 2 is a diagram showing a specific configuration of a diagnostic device, and FIG. 3 is a diagram showing a function of a timer. is there. 11 ... Service controller, 12 ... Standby controller, 13 ... Switcher, 14 ... Diagnostic device, s10 ... Process amount, s11 ... Service controller output, s12 ... Standby controller Output, s13: Controller output, s14: Switching signal, 21 to 24: Comparison / determination unit, 31 to 3
4… Timer, s31… Sudden failure controller output deviation large signal, s32… Slow failure controller output deviation large signal, s33… Flow rate deviation large signal, s34… SG water level deviation large signal, 41,42… … OR
Circuit, s41: Large controller output deviation signal, s42: Large process deviation signal, 50: AND circuit.

Claims (1)

(57) [Claims] A control deviation between an output of a normally used controller and an output of a standby controller having a control function equivalent to that of the regular controller and used in place of the regular controller is determined in advance. When the set value deviates by a preset set time and a deviation between a control amount and a reference value, which is a control result of the service controller, deviates from a preset set value by a preset set time, the common use is performed. In a diagnostic method of diagnosing the controller as abnormal, the failure detection condition including the set value and the set time for each series corresponding to each of the deviation inputs includes a combination of a large set value and a short set time. Condition 1 and a second condition consisting of a combination of a small set value and a long set time, and a sudden failure of the service controller in which the deviation input satisfies the first condition; and Deviation input Is configured to detect a slow failure of the service controller that satisfies the second condition.