JPH0213323B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an abnormality testing device, and particularly to an abnormality testing device suitable for detecting abnormalities in a device having a dual system controller.

In order to improve reliability in controlling the equipment,
A so-called dual system is adopted over part or the entire area of the path from the detection section to the control output section. This dual system operates simultaneously, and is configured to switch to the other when one system fails.

FIG. 1 is a block diagram of a pressure control system employing a dual system.

The example shown in FIG. 1 detects the main steam pressure in a system of a main steam pipe 1 used in a nuclear reactor, a bypass pipe 2 connected to this, and supplies steam to a turbine using a control valve 3 and a condenser. It controls the bypass valve 4 that supplies steam to and flows out.

Pressure signals P _E and P _M are detected by pressure sensors 5 and 6 installed in the main steam pipe 1 . The pressure signal P _E is subtracted from the pressure set value P _ES by an adder 7 serving as a first comparing means, and is output as a control signal to a controller E8 serving as a main control means forming a main component of the main control system. . On the other hand, the pressure signal P _M is subtracted from the pressure set value P _MS by an adder 9 as a second comparing means, and is controlled by a controller M10 as a standby control means which is a main component of the standby control system. Output as a signal. The controller 8 outputs a control signal ε _E , and the controller 10 outputs a control signal ε _M. The pressure sensors 5 and 6 as operating state detection means for detecting the operating state of the controlled object have the same specifications, but the controllers 8 and 10 have different characteristics and are constructed so that their output waveforms are similar. In addition, in the example shown in Fig. 1, the pressure setting value _PES is set to a value larger than _PMS , and the output of the controller 8 is normally used for control, and the controller 10 is used as a standby system. .

The higher-level output of both controllers is selected by the high-value priority gate 11 (that is, the output of the controller 10 is selected) and output to the adder 12. here,
Although the case of giving priority to high values is shown, giving priority to low values may also be adopted, and this is determined depending on which one is more safely controlled. In the example shown in FIG. 1, high value priority is adopted because the control valve 3 operates in the direction of closing when the gate output increases.

The adder 12 subtracts the control signal and the feedback signal, and outputs the subtracted value to the control servo device 13. Control valve servo device 1
The output signal of limiter 1 determines the operating region.
4 to the control valve drive unit 15. The control valve driving section 15 drives the control valve 3 to open and close, thereby controlling the main steam pressure of the turbine to be constant. That is, the high value priority gate 11, the adder 12,
The control valve servo device 13, the limiter 14, and the control valve drive section 15 constitute a drive means. The output of limiter 14 is applied to adder 12 as a feedback signal.

On the other hand, the output of adder 12 is applied to adder 16, and converted into control signal ε _BV by subtraction with bias voltage V _B . This signal is supplied to the bypass valve servo device 17. By driving the bypass valve servo device 17, the bypass valve 4 is opened and closed.

The controller 8 performs processing using the (lead/lag) compensation transfer function characteristic shown in equation (1) to obtain a control signal ε _E.

G _E (s) = (1+T _1E・s)/(1+T _2E・s)
...(1) However, s: Laplace operator T _1E : Advance time constant T _2E : Delay time constant Similarly, the controller 10 obtains the control signal ε _M using the transfer function shown in equation (2).

G _M (s) = (1+T _1M・s)/(1+T _2M・s)
(2) The high value priority gate 11 selects the larger one of the control signals ε _E and ε _M and applies it to the control valve servo device 13 .

In a boiling water reactor (BWR), as the pressure increases, the reactor power increases, so the control signals ε _E and ε _M
Select the larger of the two, i.e. the pressure setpoint P _ES
and P _MS , whichever is smaller, is controlled to improve safety. Further, the operator can arbitrarily change P _MS and P _ES and select a desired control system using the high value priority gate 11.

Upper limit or limiter 14 of control valve drive unit 15
When the control signal ε _CV increases,
A constant value bias V _B is subtracted to obtain a bypass valve control signal ε _BV .

In a normal BWR pressure control system, when everything is normal, responses of ε _M and ε _E as shown in Figure 2 are obtained. In other words, equation (3) holds true in equations (1) and (2).

T _1M T _1E T _2M T _2E ...(3) The control valve 3 or the bypass valve 4 is operated by the output signal _{ε E} of the controller 8, and the pressure change p is detected by the respective pressure sensors 5 and 6. , control signal ε _E ,
ε _M has a substantially similar shape that has been shifted in parallel by the difference in pressure setting values ΔP _SET = P _MS −P _ES .

However, the signal path relating only to controller 8 or 10 (i.e. from pressure sensor to high priority gate 11
When an abnormality occurs in any of the paths leading to the control loop (herein referred to as a control loop), the similarity shown in FIG. 2 collapses, resulting in the characteristics shown in FIG. 3. The example shown in FIG. 3 is a case where the pressure sensor 6 becomes clogged, and as a result, the time constant of the controller 10 becomes abnormally long.

In this case, even if there is an abnormality in the standby control system, there is no abnormality in the main control system, so the control valve 3 can be accurately controlled based on the output signal of the controller 8. but,
When the control is switched to the standby control system, the control valve 3 cannot be accurately controlled. Therefore, JP-A-51
- As described in Publication No. 104237, the deviation between the control signal ε _E and the control signal ε _M is monitored, and when the deviation deviates from the set value, it is determined that an abnormality has occurred in the standby control system. be able to.

However, even if the deviation is included in the set value, an abnormality may have occurred in the standby control system, and the above-described method is not sufficient to determine whether there is an abnormality in the standby control system.

An object of the present invention is to provide an abnormality testing device that can detect the presence or absence of an abnormality in a standby control system of a dual control system consisting of a main control system and a standby control system based on control signals of each control system. It is in.

In order to achieve the above object, the present invention includes: an operating state detecting means for detecting the operating state of a controlled object; a first comparing means for comparing a detection output of the operating state detecting means with a first set value; The main components of the main control system include main control means that outputs a control signal according to the comparison result of the first comparison means, and a second control means that compares the detected output of the operating state detection means with a second setting value.
As a means of comparison and the main components of the standby control system,
A standby control means outputs a control signal according to the comparison result of the second comparison means, and one control signal is selected from among the control signals from each of the control means, and the control target is controlled based on the selected control signal. In the control system, the control system includes a drive means for driving the standby control system, and a comparison means for abnormality determination that sequentially compares the control signal from the standby control means with a determination reference value, and a comparison result of the comparison means to determine whether or not there is an abnormality in the standby control system. The first step to determine
a determining means for sequentially taking in the control signals from each of the control means and calculating a degree of similarity based on a time response between both control signals over a period from the present moment to a certain time before, and the calculating means during execution of the main control system. and a second determining means for determining whether or not there is an abnormality in the standby control system based on the calculation result.

FIG. 4 is a block diagram showing an embodiment of the present invention.

The control signals ε _E and ε _M are taken in via the input device 20 , and are taken in by the multiplexer 21 into the arithmetic unit 22 at fixed time intervals T determined by the timer 23 . The arithmetic unit 22 determines the degree of similarity of the control signal characteristics as described below, and the output device 24 issues an alarm or display depending on the content of the determination. Arithmetic device 2
In step 2, the degree of similarity between the waveforms of the control signals ε _E and ε _M is evaluated to detect an abnormality in the controller loop that is in a standby state. That is, the arithmetic device 22
includes a first comparison means for abnormality determination that sequentially compares the control signal ε _E and the first determination reference value, and a first comparison means for abnormality determination that sequentially compares the control signal _ε
A second comparison means for abnormality determination sequentially compares the first and second comparison means for abnormality determination, and the presence or absence of an abnormality in the main control system and standby control system based on the comparison results of the first and second comparison means for abnormality determination. a first determination means for determining the respective control signals ε E and ε _M ; a calculation means for sequentially taking in each control signal ε _E and ε M and calculating a degree of similarity based on a time response between the two control signals over a period from the current moment to a certain period of time; It has a second determination means for determining the presence or absence of an abnormality in the main control system and the standby control system based on the calculation result of the calculation means, and the main control system and the standby control system are determined based on the control signals ε _E and ε _M. The presence or absence of an abnormality in the standby control system is determined in two stages. The processing contents will be explained in detail with reference to a diagram below.

FIG. 5 is a processing flow chart of the present invention.
Such a series of processing is most suitable when processed by a digital processing device, for example, an electronic computer.

First, control signals ε _M , ε _E corresponding to FIG.
In block 31, data regarding the time period T is taken in for a certain period of time T. Then, in block 32, the control signals ε _M ,
An independent check is performed on the data of ε _E , and cases where ε _M and ε _E are clearly abnormal are extracted. The contents of the check include upper and lower limit values, upper and lower limit values of the rate of change, etc. If an abnormality is found, the controller loop corresponding to ε _M and ε _E is determined to be abnormal in block 33. In block 34, ε _M and ε _E are compared with each other to evaluate the degree of similarity of the time response waveforms. As the evaluation value J for quantitatively evaluating the degree of similarity (4)
Consider the formula.

J=1/T∫ ^T ₀ [ω ₁・(ε _M −ε _E ) ² +ω ₂・(ε〓 _M −
ε〓 _E ) ² 〕d + _M〓 ⁱ⁼¹ [ω ₃ (t ⁱ _PE −t ⁱ _PM ) ² +ω ₄・(ε _E (t ⁱ _PE )−ε _M (t ⁱ _PM )) ² ]/M ……(Four
) Here, ε〓; Time rate of change of ε T; Data recording time M; Total of upper and lower peaks occurring within time T ^{t i} _PE , t ⁱ _PM ; i-th of ε _E and ε _M , respectively. th peak occurrence time ω ₁ to ω ₄ ; Weighting coefficient (0ω _i 1) Of J, ω ₁ is the weighting coefficient for the difference signal between ε _M and ε _E , and ω ₂ is the weight coefficient for the time differential of ε _M and ε _E. This is integrated over time T. Moreover, ω ₄ and ω ₃ are weighting coefficients for the deviation between the peak value and the peak occurrence time.

The similarity Sim is defined as a quantity equivalent to the reciprocal of J using equation (5).

Sim≡(1−e〓 ^/J ) ……(5) α is a positive coefficient (constant) In block 35, when Sim is smaller than a constant value δ, the similarity is bad, and the closer Sim is to 1, the worse the similarity is. It is judged as good.

In block 36, by looking at ε _M and ε _E or, for further confirmation, the output value of the high value priority gate 11, it is determined whether control during time T was performed at ε _E or ε _M.

Although the degree of similarity is poor and the system is under control with ε _E , the system as a whole is being controlled normally, so it can be detected that there is an abnormality in the loop of the controller 10 that is on standby. The opposite is true when controlling with ε _M.

On the other hand, if the response of the entire system is abnormal, the following judgment can be made by looking at the degree of similarity between ε _E and ε _M. If the similarity is good, there is an abnormality in the loop shared by the loop of the controller 10 and the loop of the controller 8 (for example, the control valve servo device 13, the bypass valve servo device 17), and if the similarity is bad, the current control There is an abnormality in the internal controller loop. This determination is made in block 37, but even if the degree of similarity is good, a sudden change may appear in the waveform, and such a waveform can only be recognized by performing frequency analysis or the like.

By repeating the above procedure at an appropriate period p, it is possible to detect an abnormality in a control system having dual controllers and to know the location where the abnormality occurs.

In particular, the standby system is rarely used all the time, so
By constantly checking the health of the standby system using this method, safety and a sense of security for operators can be ensured in the event of an abnormality.

In another embodiment of the present invention, a particular BWR may be equipped with two different mechanisms (electrical and mechanical) as pressure control controllers.

In this case, the actual transfer function shapes G _E (s) and G _M (s) of the controller are different between the electrical type and the mechanical type. In addition, even if converted to the form of equation (1) equivalently, it will continue, and since the values of the delay time constants are different, there will be a difference between the signals of ε _E and ε _M even in normal conditions, as shown in Figure 6. In some cases, the degree of similarity is not very good.

In this case, either ε _M or ε _E is used as the base (usually the slower response, ie, ε _M is used as the base).
When ε _M is the base, the result ε ^* _E obtained by multiplying ε _M by the compensation transfer characteristic G _COM (s) shown in equation (6) is approximately equal to the base ε _M during normal operation. Select the compensation transfer characteristics as follows.

G _COM (s) = 1 + T _C · s / 1 + T _A s + T _B · s ² ... (6) T _A , T _B , T _C : Adjustment constants If you do this, ε ^* _E as shown in Figure 7 (=
G _COM (t)·ε _E ) and ε _M can have a high degree of similarity during normal operation.

Therefore, if (ε _M and ε ^* _E ) are used instead of (ε _M and ε _E ) in the method described in the embodiment of the invention,
Abnormality can be determined using exactly the same argument.

As is clear from the above, according to the present invention, the presence or absence of an abnormality in the standby control system is determined in two stages based on each control signal of the main control system and the standby control system. can be reliably detected.

[Brief explanation of drawings]

Figure 1 is a block diagram of a pressure control system that employs a dual system, Figure 2 is a control signal characteristic diagram obtained when the equipment in Figure 1 is normal, and Figure 3 is a diagram of the control signal characteristics obtained when the system in Figure 1 is abnormal. 4 is a block diagram of an embodiment of the present invention, FIG. 5 is a processing flowchart of the present invention, and FIG. 6 is a diagram of the system shown in FIG. 1 when there are differences in characteristics even in normal conditions. Control signal characteristic diagram FIG. 7 is a control signal characteristic diagram corrected according to the present invention. 1...Main steam piping, 2...Bypass piping, 3...Control valve, 4...Bypass valve, 5, 6...Pressure sensor, 7,
9, 12, 16... Adder, 8, 10... Controller, 1
1...High value priority gate, 13...Control valve servo device,
14... Limiter, 15... Control valve drive unit, 17... Bypass valve servo device, 20... Input device, 21... Multiplexer, 22... Arithmetic device, 23... Timer,
24...Output device.

Claims (1)

[Claims] 1. An operating state detecting means for detecting the operating state of the controlled object, a first comparison means for comparing the detection output of the operating state detecting means and a first set value, and a first comparing means as a main component of the main control system. a main control means that outputs a control signal according to the comparison result of the first comparison means; a second comparison means that compares the detection output of the operating state detection means with a second set value; and a main control means of the standby control system. The components include a standby control means that outputs a control signal according to the comparison result of the second comparison means, and a standby control means that selects one control signal from among the control signals from each of the control means, and based on the selected control signal. In a control system, the control system includes: a drive means for driving a controlled object, and a comparison means for abnormality determination that sequentially compares a control signal from the standby control means with a determination reference value; a first determination means for determining the presence or absence of an abnormality in the control means; a calculation means for sequentially taking in the control signals from each of the control means and calculating a degree of similarity based on a time response between the two control signals over a period from the present time up to a certain time; An abnormality testing device comprising: second determining means for determining whether or not there is an abnormality in the standby control system based on the calculation result of the calculating means during execution of the control system.