JPH0430604B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention includes a regular system control device that performs integral calculations and a standby system control device that performs the same type of calculations,
This invention relates to an improvement in a control system in which the output ends of these two control devices are connected via a switch.

For example, a control system for a PWR (pressurized water reactor) plant water supply control system is constructed as shown in FIG. That is, 1A takes in a plurality of process quantities P from a controlled plant (not shown), performs an integral (hereinafter abbreviated as PI) operation on them, and outputs a regular system control signal Qa that brings the process quantity P closer to the target value. It is a regular system control device,
IB is a standby control device that performs the same type of calculations.
The standby system control signal Qb is output in the same way as above. 2
is a control system switching device which selects one of the above-mentioned regular system and standby system control signals Qa and Qb and supplies this selection signal to the controlled plant as a control signal R. 3 is an abnormality diagnostic device that diagnoses an abnormality in the regular system control device IA based on the process amount P and the deviation between the regular system control signal Qa and the standby system control signal Qb. Give a switching signal S,
Both control devices 1A and 1B are switched.

In the control system with the above configuration, the regular system control signal
Regular system control equipment 1A where Qa changes rapidly
In response to a failure, a deviation between the regular system control signal Qa and the standby system control signal Qb and a fluctuation in the process amount P occur immediately, so the abnormality diagnostic device 3 can detect an abnormality in the regular system control device 1A in a short time. . However, in the case of a failure of the regular system control device 1A in which the regular system control signal Qa changes slowly or becomes fixed, the process amount P changes slowly, and therefore an abnormality occurs. Detector 3 is the regular system control device 1A
It takes a lot of time to detect abnormalities.

In the case of a failure of the regular system control device 1A as described above, the abnormality diagnostic device 3
When an abnormality is detected and the switching signal S is output, the standby system control signal Qb has a value far different from the regular system control signal Qa. The reason is that both the regular system control device 1A and the standby system control device 1B are PI
Because it is an arithmetic operation type, it integrates minute deviations in the process amount P, so after a long period of time, the value becomes completely different from the original value of the process amount P. It is. The standby system control signal Qb that has changed in this way has an excessive value with respect to the fluctuation of the process amount P, so the regular system control signal Qb
When switching from Qa to the standby system control signal Qb, the process amount P fluctuates significantly in the direction opposite to the deviation before switching compared to the target value, causing a large disturbance to the controlled plant.

The present invention was made based on the above circumstances, and
The purpose of this is that in a control system equipped with integral operation type control equipment for the regular system and standby system, the standby system can be operated without disturbing the controlled plant in the event of any failure of the regular system control equipment. The object of the present invention is to provide a control system that can be handled by a control device.

According to the present invention, in a control system in which a regular system control device that performs integral calculations and a standby system control device that performs the same type of calculation are installed in parallel, and the output ends of these two control devices are connected via a switch, tracking is performed. The system is equipped with a device and an abnormality diagnosing device to adjust the output level when switching the output of both of the above control devices, and when the regular system control device fails due to a sudden change in its control signal, the above abnormality diagnosing device and an abnormality diagnostic device are installed. The switching device switches to the standby system control device, and if the regular system control device has a failure due to a slow change in its control signal, the tracking device detects the output deviation between the regular system control device and the standby system control device. The control output of the regular system control device at the time when a predetermined value is reached is given to the standby system control device as a tracking signal, and the standby system control device is switched by the abnormality diagnostic device and the switching device. There is.

The control system according to the present invention will be explained below according to an embodiment shown in FIG. In FIG. 2, the same parts as in FIG. 1 are given the same reference numerals, and their explanations will be omitted. That is, this embodiment has a configuration in which a tracking device 4 shown by a dashed line in the figure is added to the conventional device shown in FIG. In the tracking device 4, 4A takes in the regular system control signal Qa and the standby system control signal Qb, respectively, and outputs the regular system control signal Qa and the standby system control signal when the regular system control device 1A fails.
This is a tracking setting circuit that outputs, as a tracking signal T, a normal control output value of the regular system control device 1A stored in advance in a state where the deviation from Qb is small. 4B takes in the process amount P and determines whether the failure is due to a rapid change (hereinafter referred to as a sudden failure) or a failure due to a slow change (hereinafter referred to as a slow failure) when the regular system control device 1A fails. This is a determination circuit that determines whether or not the current condition is the same as the one described above, and outputs a determination signal V only in the case of a slow failure. 4
C is a tracking signal output circuit that provides the tracking signal T to the standby control device 1B when the determination signal V is applied.

Next, regarding the operation of this embodiment configured as described above, the apparatus of this embodiment will be used as a controlled plant.
The case where it is applied to the PWR Plato water supply control system will be explained with reference to FIG. 2 and FIGS. 3a and 3b.
Figure 3a shows the characteristics of the control output R, SG (steam generator) water level and time T when the tracking device 4 operates during a slow failure, and Figure 3b shows the characteristics of the time T when the tracking device 4 operates during a slow failure. If the tracking device 4 does not operate, (same as the conventional example)
The characteristics of control output R, SG water level, and time T are shown. In addition, in Fig. 3a and b, the output of the standby system control signal Qb decreases as the SG water level exceeds the reference value, and finally reaches zero, and the standby system control signal Qb continues to be zero. This indicates that the value exceeds zero again at switching time t2 or after. This is because the output of the standby system control signal Qb increases or decreases in response to increases or decreases in the SG water level, which is the object to be controlled.

Next, the operation of the above configuration will be described. That is, when the regular system control device 1A is not out of order, the regular system control signal is obtained by performing a predetermined integral calculation on the process amount P.
Qa is provided to the controlled plant via the control system switching device 2 as the control output R.

Next, if the failure is due to a sudden change in the regular system control device 1A, the regular system control signal Qa is
The deviation between and the standby system control signal Qb and the process amount P
Since the fluctuation occurs immediately, the abnormality diagnostic device 3 operates in a short time, detects the abnormality in the regular system control device 1A, gives a switching signal S to the control system switching device 2, starts the standby system control device 1B, Allow predetermined control to continue.

On the other hand, if a failure occurs in the regular system control device 1A at time _t1 as shown in FIG. 3a, the regular system control signal Qa and the standby system control signal Qb
The deviation becomes larger. Then, at time t ₂ ,
The determination circuit 4B provides the determination signal V to the tracking signal output circuit 4c, and at this time, the switching signal S based on the abnormality detection of the abnormality diagnostic device 3 is also provided to the tracking signal output circuit 4c. When the inputs V and S are both received, the signal T, which is the output of the tracking signal setting circuit 4A, is operated to be applied to the standby system control device 1B via the tracking signal output circuit 4c. Here, the signal T is the output value of the regular system control device 1A at the time when the deviation between the regular system control signal Qa and the standby system control signal Qb reaches a predetermined deviation. Also,
Since the abnormality diagnostic device 3 gives the switching signal S to the control system switching device 2, the standby system control device 1B is selected instead of the regular system control device 1A as the device that sends the control signal to the controlled plant, and as shown in FIG. A standby system control signal Qb shown by a broken line is given as a control output R to the controlled plant.

According to the above control operation, the change (overshoot) in the SG water level in the water supply control system of the PWR plant as a controlled plant after switching between the two control devices 1A and 1B is 1.5% of the reference value as a result of simulation. It has been confirmed that this will be done.

On the other hand, when the tracking device 4 of this embodiment is not activated, that is, in the conventional example, as shown in FIG. It has been verified through simulation that it shoots.

As described above, according to this embodiment, when the regular system control device 1A has a slow failure, the regular system control device 1A and the standby system control device 1B The control signal of the regular system control device 1A at the time when the output deviation reaches a predetermined value is given to the controlled plant as the output R. Therefore, it is possible to return to a normal control state in a short time without causing any major disturbance to the controlled plant, and the backup function for the controlled plant is greatly improved.

The present invention is not limited to the above embodiments, and can be implemented with various modifications without departing from the gist of the present invention.

As described above, according to the present invention, a regular system control device that performs integral calculations and a standby system control device that performs the same type of calculation are installed side by side, and the output ends of these two control devices are connected via a switch. The control system is equipped with a tracking device and an abnormality diagnostic device, and is configured to adjust the output level when switching the output of both of the above control devices, and in the case of a failure of the regular control device due to a sudden change in its control signal, The above-mentioned abnormality diagnosis device and the above-mentioned switching device switch to the standby system control device, and if the regular system control device has a failure due to a slow change in its control signal, the above-mentioned regular system control device Since the normal control output of the system control device is given as a tracking signal to the standby system control device, and the abnormality diagnostic device and the switching device are used to switch to the standby system control device, any failure of the above-mentioned regular system control device can be avoided. However, a control system can be provided that can be handled by a standby control device without causing any disturbance to the controlled plant.

[Brief explanation of drawings]

Fig. 1 is a block diagram showing a conventional control system, Fig. 2 is a block diagram showing an embodiment of the control system according to the present invention, and Figs. 3 a and b show the same embodiment applied to a PWR plant water supply control system. It is a characteristic diagram for explaining the effect in the case of 1A... Regular system control device, 1B... Standby system control device, 2... Control system switching device, 3... Abnormality diagnostic device, 4... Tracking device, 4A... Tracking signal setting circuit, 4B... Judgment circuit, 4C... Tracking signal output circuit .

Claims (1)

[Scope of Claims] 1. A regular system control device that takes in a plurality of process quantities from a controlled plant, performs an integral operation on them, and outputs a regular system control signal for bringing the process quantities closer to a target value; a standby system control device that performs the same type of calculation as the regular system control device and outputs a standby system control signal of the same type as the regular system control signal; a control system switching device that takes in the standby system control signal output from the control device and supplies one of them as a control signal to the controlled plant; and the process amount, the regular system control signal, and the standby system control signal. An abnormality diagnosis of the regular system control device is performed based on the deviation from the above, and if an abnormality is detected, the regular system control device connected to the controlled plant is switched to the standby system control device. an abnormality diagnostic device that provides a switching signal to a control system switching device; When the diagnostic device detects that the regular system control device is at fault, and also determines that the failure of the regular system control device is accompanied by a slow change based on the process amount, the malfunction diagnostic device detects that the regular system control device is malfunctioning. means for providing the held control output to the standby control device when the normal control device is switched to the standby control device due to a failure detected in the normal control device; , a control system consisting of.