JPH0830323A - Method and device for control - Google Patents

Abstract

PURPOSE:To improve the workability and reliability of a system by changing an operation target and the set value of other system corresponding to the value of the system to be a factor when the normal states of parameters to be controlled for respective systems conflict with values under operating. CONSTITUTION:Concerning a lot of normal states, these state amounts are mutually related and previously stored in a normal state amount data base 101. Based on state amounts 109 to be controlled of respective systems 107 and 108 consisting of the plant or a system 104, an abnormal system discriminating device 103 discriminates any statically abnormal system and transmits the discriminated result 111 containing the abnormal system (such as the A system 107, for example) and the state amount to be controlled for this system. While receiving this discriminated result 111, a state amount setter 102 accesses the normal state amount data base 101 and retrieves set values 110 of the state amounts of all the other normal systems so that the state amount to be controlled of this system 107 can be a normal value and while receiving this retrieved result, the state amount setter 102 changes the set values of the respective systems 107 and 108.

Description

Detailed Description of the Invention

[0001]

This invention relates to a plant or system consisting of several systems controlled by independent control systems,
That is, for example, the present invention relates to a control device and a control method for a power plant, a chemical plant, an air conditioning system, a wide area cooling and heating system, and the like.

[0002]

2. Description of the Related Art The prior art relating to improvement of reliability of plants and systems is shown below.

Duplex system Also called a standby system, when a normally used system fails, the input / output of the system is switched to the standby system to continue online processing.

Dual system Also called a parallel system, exactly the same processing is performed in synchronization by several systems, and the output is determined by majority voting.

Japanese Patent Application No. 3-194601 In a system that can be divided into a large number of subsystems, each subsystem detects an abnormality or failure in a neighboring subsystem, and several subsystems share the processing of the failed subsystem. And process. Therefore, it is a system that can be considered as a parallel multipurpose duplex system.

[0006]

It is desirable to realize the same system reliability improvement as the above-mentioned conventional technique without providing a preliminary subsystem or a preliminary processing capacity in advance as in the above-mentioned conventional technique. It is rare.

An object of the present invention is to provide a control method and a control device capable of improving the operating rate of a plant or system and realizing the reliability improvement without previously providing a spare subsystem or a spare processing capacity. Especially.

[0008]

Means for Solving the Problems The features of the present invention for achieving the above object are a control system for independently controlling all the systems constituting a plant or a system, and a steady state of a state quantity controlled by all the systems. Based on the steady state state quantity database that stores the relationship of values for many steady states and the steady state state quantity database, set values for all other systems are determined according to the controlled state quantity of an arbitrary system. It is provided with a state quantity setting device and an abnormal system discriminating device for discriminating a system having a static abnormality based on a steady state state database.

[0009]

The steady-state state quantity database stores in advance the steady-state value of the state quantity controlled by each system constituting the plant or system in association with a large number of steady states.

The abnormal system discriminating apparatus discriminates a system having a static abnormality based on the steady state state quantity database, the set value of each system and the controlled state quantity of each system.

The state quantity setting device controls the states of all other normal systems so that the controlled state quantity of the system becomes a value in the steady state based on the determination result and the steady state state quantity database. Change the amount setting value.

[0012]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS FIG. 1 is a schematic diagram showing the overall structure of the present invention and a system or plant to which the present invention is applied. The present invention is a steady state state quantity database 101, a state quantity setting device 102,
It is composed of an abnormal system discriminating apparatus 103 and a plant or system 104 to which the present invention is applied. In many cases, the state quantities controlled by the respective systems 107 to 108 constituting the plant or system 104 are related to each other through the process 106.

The steady-state state quantity database 101 stores a large number of steady-state states in association with each other in advance.

The abnormal system discriminating device 103 includes each system 107-
Based on the set value 110 of 108 and the controlled state quantity 109 of each system 107 to 108, the system having a static abnormality is determined, and the state quantity setting device 102 is notified to the abnormal system (here,
The determination result 111 including the value of the state quantity controlled by the system) is transmitted.

The state quantity setting device 102 determines whether the determination result 11
In response to 1, the steady state state quantity database 101 is accessed, and the set values 110 of the state quantities controlled by all other normal systems are searched so that the controlled state quantity of the system 107 becomes the value in the steady state. To do. The state quantity setting device 102
Upon receiving this result 112, the set value 110 of each system 107 to 108 is changed.

In describing each device, the concept and scope of application of the present invention will be briefly described below. The present invention relates to a control method and apparatus for continuing operation even if any one system fails in a plant or system composed of several systems.
Note that the system failure considered here is intended for those caused by the failure of the control device where problems have become apparent with the recent digitization of control systems, and for the failure of controllers and signal detection systems. Not something to do.

In view of this, next, the failure mode of the control device will be considered. Since many power plants, chemical plants, air conditioning systems and wide-area cooling and heating systems use valves as their actuators, Pay attention to. Many valves are composed of a link mechanism, a spring, a cylinder for boosting power, and its pressure source. Its failure mode is gradually caused by static failure due to sticking of the mechanical part, spring fatigue, pressure leakage, etc. A quasi-static failure in which the valve opens or closes or a step failure due to breakage of hydraulic piping or links is considered. Of these, the present invention is targeted at the former two cases.

The difference between the conventional idea and the present invention is
Next, description will be made with reference to FIG. Conventional example I201 is a schematic diagram of a concept of a dual system or a duplex system, and conventional example II202 is a schematic diagram of a concept of cooperation in normal control including Japanese Patent Application No. 3-194601. As shown in the schematic diagram 203, the present invention changes the set values of other normal systems according to the failed system regardless of the operation target, and tries to realize steady operation including the failed system. Is. If the failure mode of the failed system is the above-mentioned two cases, even if the other system is made to follow this, there is not much problem in terms of stable operation. On the other hand, in the conventional example I201, the failed system is isolated from the plant or the system, and the operation according to the operation target is attempted, and any failure mode can be dealt with.
This causes complication of operation such as switching operation and complication due to multiplexing of plants or systems. Conventional example II202
Is to utilize the characteristics of the process in the plant or system well, and to utilize the interference of the amount of state controlled by each system to follow the faulty system in the normal system and try to operate according to the operation target. Is. Although it is an ideal system, it is difficult to design such a control system in reality.

From this, when the superiority of the present invention over the conventional example is briefly described, it means that the conventional example I is not complicated and the conventional example II is not difficult to design. .

An example of the outline and processing of each device that realizes the present invention having such advantages will be described below with reference to FIGS.

FIG. 3 shows an embodiment of the steady state state quantity database 101. In this embodiment, each system 107-108
Variable 3 that directly manipulates the state variables related to the control of
01, a state variable 302 affected by the state variable 301, and a state variable 303 that influences how the state variable 301 influences the state variable 302.

For example, in a steam power plant, a pressure control system for controlling the valve opening of a steam flow control valve controls the steam flow rate so as to keep the tank pressure constant. At this time, the state variables that can be detected are the flow rate and the pressure, and the flow rate of these changes according to the operating state, that is, the amount of heat generation. Therefore, the state variable 301 operated by the pressure control system is the vapor flow rate, the state variable 302 affected by it is the tank pressure, and the state variable 303 affecting the manner of influence is the calorific value.
Since this cannot be directly detected, it becomes the supply amount of fuel and air to the heater.

The water supply control system is also characterized by several similar state variables, but a pair of steam flow control system and water supply control system are provided between the steam flow control system and the water supply control system in accordance with the operating state, such as the main steam flow rate and the feed water flow rate. There is a corresponding relationship to one. On the other hand, the tank pressure is constant in the steady state even if the feed water flow rate changes, and the tank water level becomes constant in the steady state even if the steam flow rate changes. Therefore, a directed link 304 is provided between variables such as the main steam flow rate and the feed water flow rate, which are controlled independently in each system but have a one-to-one relationship through the process. Regarding the use of this directed link 304,
A description will be given simultaneously with the description of the processing in the state quantity setting device 102 using FIG. The example shown with ex and symbols is for a boiling water nuclear power plant.

FIG. 4 shows an embodiment of the steady state state quantity database creation processing. First, the three types of state variables are extracted for each system (step 401), and then the state variables 301 and 302 that can be directly controlled among the state variables related to each system are extracted (step 402). Next, the state variable 305 that is the starting point of the directed link 304 is selected from these (step 403), and the range to be assumed for these state variables is set (step 4).
04). Thereafter, for each state variable, the resolution for storing data or the value to be stored within the set range is set (step 405). For all the extracted state variables 305, the state variables 301, 302, 302 of each system are set to the resolution or value set in step 404.
The steady state value of 303 and its variation range are detected by the actual operation (step 407) (step 40
9) or simulation (step 408) to identify (step 409). Whether it is based on simulation or actual measurement is determined, for example, by considering the degree of deviation from normal operation and by the judgment of the designer or the operator during adjustment (step 406). If you do not set a range that cannot be actually measured, this process is
It can be realized only by steps 407 and 409. State variables 301, 302, 30 of each system thus obtained
The value in the steady state of No. 3 and its variation range are recorded in the steady state quantity database 101.

Next, referring to FIG. 5, the abnormal system discriminating apparatus 103
The basic processing in step will be described. That is, in this processing, the value of a predetermined state variable for each system is detected from the plant or system (step 501), and it is determined from this and the command value whether or not the system is a static abnormality ( Step 502). If it is a static abnormality, the discrimination result 111 including the abnormal system and the value of the state quantity controlled by the system is transmitted (step 503).
Otherwise, the above steps 501 to 503
Repeat up to.

Next, the abnormality determination processing of step 502 will be described with reference to FIGS. 6 and 7 by taking the feed water control system and the pressure control system of the steam power plant as an example.

Single element water supply control system 6 having the simplest structure
On the other hand, when the steady operation is considered, the relationship 602 between the operating state and the water level, the relationship 602 between the operating state and the water supply flow rate, and the relationship 603 between the water level deviation and the water supply flow rate deviation in a certain operating state are as shown in the figure. Further, when the fluctuation range in the steady state described in FIG. 4 is shown in the figure, it becomes 604, and from this, the abnormality of the water supply control system can be determined by the point (water level deviation, water supply flow rate) 605 in the figure. Further, even in the case of the three-element control system 606 which is more commonly used, the same determination can be made by correcting the deviation between the feed water flow rate and the main steam flow rate.

In the case of the pressure control system, the relationship between the pressure and the calorific value during normal operation 701, the relationship between the steam flow rate and the calorific value 70
2 and the relationship between pressure and flow rate at a certain calorific value 703
Becomes like the figure. When the tank pressure fluctuates from the target pressure, the steam flow rate changes in accordance with the cross-sectional area of the valve, but the pressure control system does not correspond to the pressure flow rate characteristic 704 in the cross-sectional area that satisfies the relationship between the pressure and the flow rate in the steady state. In normal operation, if the pressure is high, the upper side of the characteristic curve 704 is set, and if the pressure is low, the lower region 705 of the characteristic curve 704 is set.
Should try to bring the pressure closer to the target pressure through
If there is a point (pressure deviation, main steam flow rate) 706 in this area 705, it can be seen that the pressure control system is normal, and otherwise it is abnormal.

Next, basic processing in the state quantity setting device 102 will be described with reference to FIG. In this processing, based on the abnormal system indicated by the discrimination result 111 output from the abnormal system discriminating apparatus 103 and the value 809 of the state variable controlled by the system, the control command value of the system is discriminated by the value of the controlled state variable. It is fixed so as to be equal to the result 809 (step 801). Following this, whether or not this controlled state variable has a directed link to a state variable of another system is determined based on the steady state state quantity database 101 (step 80).
2). When there is no directed link, if there is a "affected state variable" that has a directed link to a state variable of another system, the value of the controlled state variable is equal to that of the discrimination result. The storage position of the "affected state variable" (the position in the vertical direction when the database of state variables for each system is configured as shown in Fig. 3) is the steady state state quantity. For the state variables at the end points of all valid links (step 806), a value to be taken is searched for from the database 101 (step 806) based on the position of the state variable, and the steady state state database 1 is also used.
It is read from 01 (step 807) and set as a command value for that system (step 808). Step 802
In the case where there is a directed link in, the storage position where the value of the controlled state variable becomes equal to that of the determination result is read from the steady state state quantity database 101 (step 80).
3) For all state variables at the end of the link (step 806), the value to be taken is read based on the storage position of the state variable (step 807) and set as the command value for that system (step 808). .

[0030]

According to the present invention, reliability can be improved by improving the operating rate even when the system or the system constituting the plant to which the present invention is applied is not easily multiplexed or switched. That is, when the actuators that are not multiplexed have a static failure, the state quantities of all other normal systems are changed so that the system or plant becomes steady with the state quantity controlled by the system that has become uncontrollable. By doing so, the system or plant can be stably operated.

[Brief description of drawings]

FIG. 1 is a schematic diagram of the overall configuration of a system that is a preferred embodiment of the present invention.

FIG. 2 is an explanatory diagram showing the concept of the present invention.

3 is an explanatory diagram of an embodiment of the steady state state quantity database of FIG. 1. FIG.

FIG. 4 is an explanatory diagram showing an example of a steady-state state quantity database creation process.

FIG. 5 is an explanatory diagram showing an example of processing in the abnormal system discriminating apparatus.

FIG. 6 is an explanatory diagram of an example of abnormality determination in the water level control system.

FIG. 7 is an explanatory diagram of an example of abnormality determination in the pressure control system.

FIG. 8 is an explanatory diagram showing an example of processing in a state quantity setting device.

[Explanation of Codes] 101 ... Steady-state state quantity database, 102 ... State quantity setting device, 103 ... Abnormal system discriminating device, 104 ... Applicable plant or system, 111 ... Abnormal system discriminating device discrimination result.

Claims (4)

[Claims] 1. In a plant or system comprising two or more systems controlled by independent controllers, each system detected during operation with respect to a value of a controlled parameter of each system in a steady state obtained in advance. When the values of the controlled parameters of the above are inconsistent, the control method of changing the operation target and the set value of the other system according to the value of the controlled parameter of the system causing the problem. 2. A plant or system comprising two or more systems controlled by independent control systems, wherein a system having a steady abnormality is based on the value of the controlled parameter of each system in a steady state obtained in advance. A control method that changes the operation target according to the state quantity. 3. In a plant or system consisting of two or more systems controlled by independent control systems, based on the relationship between the values of the controlled parameters of each system in a steady state obtained in advance, from the state quantity of each system A controller that identifies an abnormal system. 4. In a plant or system consisting of two or more systems controlled by independent control systems, the state quantity of an arbitrary system is determined based on the relationship between the values of the controlled parameters of each system in a steady state obtained in advance. A control device that determines the combined operation target and set values for other systems.