JPH0830962B2 - Hierarchical high reliability device - Google Patents

Description

TECHNICAL FIELD The present invention relates to a control device for a thermal power plant or a nuclear power plant,
In particular, the present invention relates to a hierarchical high reliability device suitable for obtaining high reliability at a low price.

[Background of the Invention]

In a thermal power plant or a nuclear power plant, improving the plant operation rate is indispensable for reducing the power generation cost. In particular, it is necessary to prevent the plant from shutting down and lowering the operating rate due to defective hardware of the control device or system, as much as possible.

Generally, in order to improve the operating rate, there are a method of selecting hardware parts and using a high quality one to improve the reliability, and a method of multiplexing and making the system redundant and improving the system. .

There is a limit to the improvement of reliability at the component level, so high reliability cannot be obtained unless systematically improved.
In order to improve the system, the manual backup system, the waiting duplex system, and the triplicate system are generally well adopted. However, the more multiplexed, the higher the reliability, but the cost also increases accordingly, which is not economical.

The situation on that side will be described with reference to the conventional example shown in FIGS. FIG. 5 is a block diagram of a water supply control system multiplexed by a conventional technique in a nuclear power plant, and FIG. 6 is a diagram showing execution time in the conventional example of FIG. The A level instructs the B level control device to perform control such as plant automation by the process computer. The B-level control device, which is a water supply control device, performs three-element control based on the reactor water level and process signals such as the main steam flow rate and the feed water flow rate. The water supply control device sends the calculation result to the control device C level closest to the control target, and finally the C level control device gives a control signal to the control target. In such a three-layer control configuration, a general method of improving reliability systematically is to make each control device double or triple. In FIG. 5, the blocks slightly visible in the upper left of the A, B, and C blocks indicate that each block is duplicated.

However, the more multiplexed, the higher the cost and not economical. In addition, the higher the hierarchical structure, the longer the time spent for transmission and the slower the calculation speed. Particularly in the method of digital calculation, the sampling period is the largest factor that determines the controllability. Generally, if the sampling period is shorter than the response time of the controlled object by one digit or more, control similar to that of the analog arithmetic device is possible. For this reason, shortening the sampling period is important in the control system configuration, and is also a factor for determining applicability.

FIG. 6 is a diagram showing a calculation time in the case of a three-layer structure.
At the C level, the calculation time T _C required by the calculation device C and the time T ₁ required for transmission are added, and the calculation time is t _C = T _C + T ₁
Becomes However, at the B level, the own computation time t _B and the transmission time T ₂ are added to the computation time t _C spent at the C level. (Here, the transmission time T is evaluated as different, but the same value T ₁ may be used if the transmission devices are the same). The calculation time at the B level is t _B = T _B + T _C + T ₁
It becomes + T ₂ . At the A level, t _A = T _A + T _B + T _C
+ T ₁ + T ₂ + T ₃ , resulting in a significant delay in computation time.

[Object of the Invention]

It is an object of the present invention to provide a hierarchical high reliability device which reduces the number of hardware components of the hierarchical control device, shortens the operation time thereof, and is highly reliable.

[Outline of Invention]

In order to achieve the above object, the present invention is a hierarchical control in which a plurality of control devices are hierarchized in at least two hierarchies so that a higher level control device monitors a lower level control device that controls a controlled object. In the device, the control device has a function of taking in the process amount input by the control device below the self level and executing the control of the control device below the self level based on the process amount. The present invention proposes a hierarchical high reliability device that constitutes a multiple system that substitutes the control function of the control device when the control device is stopped.

In the present invention, in particular, the control device has a function of taking in the process amount input by the control device below its own level and executing the control of the control device below its own level based on the process amount. When a control device below the control level is stopped, a multiplex system is configured to replace the control function of the control device, so unless the control devices of all levels are down, the control function for the control target does not decrease. Can be obtained.

Example of Invention

Next, one embodiment of the present invention will be described with reference to FIGS.

FIG. 1 is a block diagram showing an embodiment of a hierarchical high reliability device according to the present invention. The present embodiment is an example of a three-layer structure, and is composed of three layers of a higher-level control device A, a lower-level control device B, and a lowest-level control device C. The terminal device R is connected to the process in the field. Inside the terminal device R, an input circuit RI that takes in a process signal at the site, an output circuit RO that controls a controlled object at the site, and transmission devices RT _A and RT _B that are connected to a control device of three layers by signal multiplex transmission. , RT _C.

The process signal at the site grasps the condition of the plant by pressure, flow rate, water level, temperature, open / close state, and the like. For example,
If it is the pressure of the nuclear reactor, the signal of the pressure transmitter of the semiconductor detection method or the like is taken into the input circuit RI. These processes signals signal multiplexed transmission input circuit RI, connected to the transmission device RT _A to RT _C with three interferons chair bus. Transmission device RT _A ~ R
T _C is a transmission device AT to CT inside the control devices A to _C , respectively.
It is connected with and transmits a signal.

The results calculated by the control devices A to C are inversely output from the output circuit RO via the transmission device to control the controlled object.

FIG. 2 is a diagram showing the calculation time in the three-layer structure according to the embodiment of FIG. If the signals from the terminal device R are simultaneously taken in by the control devices A to C respectively, the calculation time of the calculation devices at the A to C levels will be their own calculation time T _{A to} T _C and their respective transmission times T ₁ , T ₂ , T. _{It is} an addition of ₃ and is significantly shorter. Here too, if the transmission equipment is the same, calculate all with T ₁ .

The configuration of FIG. 1 is apparently a triple system configuration without increasing the number of control devices. That is, if the control device C is stopped for some reason, the control device B or A backs up the data, and even if the control devices B and C are stopped, the control device A backs up.

3 and 4 are circuit diagrams of the input circuit RI and the output circuit RO of the terminal device R in FIG.

FIG. 3 shows a 4-input analog circuit. 0th to 3rd
The second input signal is the timing / internal address generation circuit
By the RIT, it is sequentially fetched by the multiplexer RIMPX via the input fetching units RICH0 to RICH3. Then, the output is amplified through the amplifier RIAMP and converted into a digital serial signal by the A / D converter RIAD. Digital serial signals are stored in memories RIM _{A to} RIM _C. That is, the analog signal is converted into a digital signal and written in the memory at regular intervals. The memory is from A to C, and the memory will be tripled. The information on the memory can be connected to the transmission device via the bus by the address access control RIADA, the input data buffer PIDA and the status data buffer RISA.

FIG. 4 shows an output circuit having four analog outputs. The digital signal from the transmission device takes in three signals to the output circuit section via the bus. A, B and C are output signals respectively corresponding to the control devices A, B and C in the hierarchical portion. In the connection with the transmission equipment, the address scanning control ROADA, the output data buffer RODA, the operation data buffer ROXA, the status data buffer ROSA are sequentially taken in by the output scanning control ROC,
Transmits a signal to the judgment circuit ROJ.

The determination circuit ROJ outputs the signal of C to the D / A converter R when the control device C is normal according to the states of the control devices A to C.
Output to OD. If the control device C is abnormal, B is selected, and if B is abnormal, A is selected. The output of the D / A converter becomes four analog outputs via the output multiplexer ROMPX.

As described above, according to one embodiment of the present invention, a multiplexing configuration can be realized without increasing the number of control devices, and high-speed calculation that can process in the shortest calculation time is performed, and the effect of improving reliability and economical efficiency is great. .

Although the above-described embodiment of the present invention has three layers, the same applies to multi-layers, and the same applies to the case where there are a plurality of arithmetic devices in each layer.

Furthermore, although the input circuit and the output circuit have four points,
It goes without saying that any number of points will do.

〔The invention's effect〕

According to the present invention, it is possible to obtain a hierarchical highly reliable device in which the number of parts of hardware is reduced, the control calculation time is shortened, and the reliability is increased.

[Brief description of drawings]

FIG. 1 is a block diagram showing an embodiment of a hierarchical high reliability device according to the present invention, FIG. 2 is a diagram showing a calculation time in the embodiment of FIG. 1, and FIG. 3 is an input circuit of the embodiment of FIG. FIG. 4 is a diagram showing an example of the output circuit of the embodiment of FIG. 1, FIG. 5 is a block diagram of a water supply control system multiplexed by a conventional technique in a nuclear power plant, and FIG. 5 is a diagram showing the calculation time in the conventional example. A to C ... control device, R ... terminal device, AT to CT ... transmission device,
RT _{A to} RT _C ... Transmission device, RI ... Input circuit, RO ... Output circuit.

Claims (1)

[Claims] 1. A hierarchical control device in which a plurality of control devices are hierarchized in at least two hierarchies so that a lower level control device controlling a controlled object is monitored by an upper level control device. , It has a function to take in the process amount input by the control device below its own level and execute the control of the control device below its own level based on the process amount. Hierarchical high reliability device characterized by forming a multiplex system substituting the control function of the device.