JP4541241B2 - Plant control system - Google Patents

Description

The present invention relates to a plant control system for controlling the plant by data transmission through the transmission line constituting the network.

  In a conventional plant control system, for example, a power plant control system, a master controller and a plurality of slave controllers are connected to each other via a single transmission line to form a network. While calculating the power target value of the entire power plant and performing sequence control of the entire system, it is based on the control target value and command value given from the master controller by the slave controller, and the current received power value Some power generators are individually controlled.

  By the way, in such a plant control system, if the master controller fails, the command from the controller is not given to the slave controller, so the slave controller cannot properly control each power generator, and the plant controller This causes problems such as stopping operation.

  Therefore, in the prior art, a sequence control function unit and a changeover switch are provided in each controller for slaves, and monitoring is performed between the controllers. When the master controller fails, one controller for slaves is immediately used. A technique has been proposed in which a changeover switch is activated to start up a sequence control function unit, and this slave controller is operated as a master controller (see, for example, Patent Document 1).

  In addition, another conventional technique has been proposed in which two master controllers are provided to perform so-called duplication, and when one controller fails, the other controller is immediately activated (for example, a patent). Reference 2).

Japanese Patent No. 29833319 Japanese Patent Laid-Open No. 10-63313

  However, in the prior art described in Patent Documents 1 and 2, since the transmission path connecting the master and slave controllers is a single system, when a failure occurs in the middle of the transmission path, the master The command from the controller for the slave is not given to the controller for the slave. For this reason, the controller for slaves cannot control plant equipment appropriately.

  Moreover, in the case of the prior art, when switching the control so that the slave controller operates as the master controller, the control target value and the current process value in the slave controller during the period from the start to the end of the switching. Since both of these information are lost, there is a problem that control to plant equipment becomes unstable and hunting occurs.

  Further, as described in Patent Document 2, in the case of a system in which a master controller is duplicated, an extra master controller is required, resulting in an increase in cost. In addition, conventionally, since the same data is transmitted to the duplexed transmission line at the same timing, the controller on the data receiving side simultaneously performs reception processing on the two transmission lines, and both When data is received from the network, a complicated process is required in which data is selected so that one of them is used and the other is not used, and the control sequence is complicated.

  The present invention has been made in order to solve the above-described problem. Even when a failure occurs in a part of a transmission path constituting the plant control system, or when a master controller fails, control of plant equipment is possible. A controller that can reliably prevent the occurrence of problems such as stoppage or instability of the control, can always control plant equipment smoothly and stably, and can be implemented relatively inexpensively. The purpose is to provide.

In order to achieve the above-mentioned object, the present invention forms a network by connecting a plurality of controllers to each other via a duplex transmission path, and one of the controllers is used as a master for the entire system sequence. The following configuration is adopted in the plant control system that controls each plant device individually based on the control target value and command value given from the master controller while the remaining controller is used as a slave. is doing.

That is, the plant control system according to the present invention transmits the same content data to each transmission path with a predetermined time difference from each of the controllers so as not to overlap each other in time. Status information whose value changes with each cycle is included, and when the status of the status information included in the data input via the transmission path does not change, the slave controller has failed. Therefore, one of the slave controllers is shifted to the master switching process as much as possible to become the master controller .

According to the present invention, even when a failure occurs in one of the duplexed transmission paths, data transmission can be continued through the remaining transmission paths. Further, when the controller of the master has failed, the change in the status information included in the data input via at least one transmission line does not appear, the controller for the slave controller of the failure of the master It can be securely detected, one of the controllers for the slave is switched to the controller for the master accordingly. Therefore, it is possible to reliably prevent the occurrence of problems such as the stop of the control of the plant equipment and the stop of the control, and the plant equipment can always be controlled smoothly and stably.

Embodiment 1 FIG.
FIG. 1 is a block diagram showing the entire power plant control system as an example of the plant control system in Embodiment 1, and FIG. 2 is a block diagram showing the configuration of a controller of the present invention applied to the system.

  The power plant control system according to the first embodiment includes a plurality of (three in this example) controllers 1, 2, and 3, and the controllers 1 to 3 are connected to each other via transmission lines 4p and 4s that are duplicated. A ring-type LAN is configured by being connected in the shape of a ring. And the power generators 11, 12, and 13 as plant equipment are individually connected to each controller 1-3. In this example, an optical fiber cable is applied as the transmission lines 4p and 4s constituting the ring LAN in this case. Here, one transmission line 4p is referred to as a P system and the other transmission line 4s is referred to as an S system so that the respective transmission lines 4p and 4s can be distinguished from each other.

  Among the above controllers 1 to 3, one controller 1 is defined in advance as a master for normal operation. The sequence control of the entire power plant control system, for example, the target value of the generated power of the entire power plant control system is set. The calculation results and process values from the slave controllers 2 and 3 are obtained and processing such as determining the control target value of the generated power for each of the power generators 11 to 13 is executed. At the same time, the generated power of the power generator 11 connected to itself is controlled.

  On the other hand, the remaining controllers 2 and 3 are defined in advance as slaves when normal, and the power generators 12 and 13 generate power based on control data such as control target values and command values given from the master controller 1. The power is controlled individually.

  Although the functions performed by the master controller 1 and the slave controllers 2 and 3 are different as described above, the configurations of the controllers 1 to 3 are basically the same as shown in FIG. Plant equipment control unit 101, control data calculation unit 102, transmission data creation unit 103, data transmission unit 104, data reception unit 105, control data extraction unit 106, master abnormality detection unit 107, master switching unit 108, master switching stop Unit 109 and an abnormal time response control data calculation unit 110.

  The plant equipment control unit 101 controls a power generation apparatus that is a plant equipment based on control data obtained by computation in the control data computation unit 102 and the abnormality response control data computation unit 110.

  The control data calculation unit 102 calculates control data for controlling the power generation apparatus, and the calculation result is written in a predetermined data area of a memory (not shown). In addition, when transmitting control data to another controller, the control data calculation unit 102 reads status information (for example, incremented) when the control data stored in a predetermined data area is read. Value).

  The transmission data creation unit 103 is suitable for transmitting data such as packets when transmitting the control data calculated by the control data calculation unit 102 from the data transmission unit 104 to another controller via the transmission paths 4p and 4s. It is processed into a transmission form and created as transmission data.

  The data transmission unit 104 transmits the transmission data created by the transmission data creation unit 103 to the transmission lines 4p and 4s at a predetermined time interval ΔT. Note that the time interval ΔT in this case is set to be equal to or longer than one cycle of the arithmetic processing performed by each of the controllers 1 to 3 between data reception and data transmission, for example.

  The data receiving unit 105 receives the data from each of the transmission paths 4p and 4s independently. The data receiving section 105 receives a data from any of the transmission paths 4p or 4s for a predetermined period To (> ΔT). In the configuration, even if other data is received, it is not transferred to the control data extraction unit 106.

  The control data extraction unit 106 extracts control data from the data received by the data reception unit 105. The master abnormality detection unit 107 determines whether or not the control data calculation unit 102 of the controller 1 on the master side is normal based on the status information included in the control data extracted by the control data extraction unit 106.

  When the master abnormality detection unit 107 detects an abnormality in the master controller, the master switching unit 108 executes a master switching process for operating as a master controller in response to the detected abnormality. A master declaration indicating that processing has started and a master switching completion declaration indicating that master switching processing has been completed are notified to other controllers.

  When a master declaration indicating that the master switching process has been started is notified from another controller, the master switching canceling unit 109 determines the priority of the notification source controller and the priority set in advance for itself. In comparison, when the priority of the notification source controller is higher, the master switching unit 108 outputs a command to stop the master switching process being executed. Here, it is assumed that the priority of one controller 2 is set higher than the priority of the other controller 3.

  When the master abnormality detection unit 107 detects that the control data calculation unit 102 of the master controller 1 is not normal, the master switching unit 108 transmits data indicating that the master switching process has been completed. The current process value obtained from the power generation device as the plant equipment becomes the control target value until the controller 104 notifies the other controller or receives the master switching process completion notification from the other controller. An operation for controlling the plant equipment control unit 101 is executed.

  Next, in this power plant control system, each operation when the entire system is normal, when a failure occurs in a part of the transmission lines 4p and 4s, and when the master controller 1 fails will be described.

(1) When the entire system is normal In this normal state, as shown in the flowchart of FIG. 3, for example, the master controller 1 receives process values from the slave controllers 2 and 3 via the transmission lines 4p and 4s. Such data is received (S11).

  In this case, data having the same contents arrives at the data receiving unit 105 of the master controller 1 via the P-system and S-system transmission paths 4p and 4s with a predetermined time interval ΔT. The receiving unit 105 sends only the first received data of any one of the transmission lines 4p and 4s to the control data extracting unit 106 at the next stage, and within a predetermined period To (> ΔT) from the data reception, Even if other data is received, it is not sent to the control data extraction unit 106 at the next stage. For this reason, data received later is discarded.

  In this way, when the data received in the data receiving unit 105 is sent to the control data extracting unit 106, the control data extracting unit 106 extracts control data including the process value from this data, and the control data is extracted from the control data. The result is output to the calculation unit 102.

  The control data calculation unit 102 determines the target value of the generated power of the entire plant control system based on the process value obtained via its own plant equipment control unit 101 and the process value transmitted from the slave controllers 2 and 3. Calculation is performed, and calculation processing such as determining a control target value of generated power for each of the power generation devices 11 to 13 is executed (S12). Then, the control target value and command value data of the generated power for each of the power generators 11 to 13 determined in this way are written in a predetermined data area of a memory (not shown).

  Moreover, since this control data calculating part 102 reads the control target value of the generated electric power determined about the own power generation apparatus 11, and gives it to the plant equipment control part 101, the plant equipment control part 101 is based on this control target value. The generated power of the power generator 11 connected to itself is controlled.

  Further, the control data calculation unit 102 transmits predetermined control data such as a control target value and a command value of the generated power to the slave controllers 2 and 3 via the transmission lines 4p and 4s. The control data stored in the area is read and sent to the transmission data creation unit 103. At this time, status information (for example, an increment value) whose value is updated every transmission is added to the control data.

  The transmission data creation unit 103 transmits the control data including the status information from the control data calculation unit 102 from the data transmission unit 104 to the other controllers 2 and 3 via the transmission paths 4p and 4s. The transmission data is processed into a transmission form suitable for data transmission (S13). The data transmission unit 104 transmits the transmission data from the transmission paths 4p and 4s to the slave controllers 2 and 3.

  At that time, the data transmission unit 104 transmits the transmission data having the same content to each of the transmission lines 4p and 4s with a predetermined time interval ΔT so as not to overlap each other in time. That is, for example, when the data transmission unit 104 first transmits transmission data via the P-system transmission line 4p (S14), after the time ΔT has elapsed (S15), the data having the same content is again transmitted this time. Transmission is performed via the S-system transmission line 4s (S16).

  On the other hand, in the same manner as the master controller 1, the slave controller 2 receives the same data via the P-system and S-system transmission lines 4p and 4s at a predetermined time interval ΔT. 105 sends only the first data received via any one of the transmission lines 4p or 4s to the control data extraction unit 106 at the next stage, and within a predetermined period To (> ΔT) from the data reception, Is not sent to the control data extraction unit 106 at the next stage (S21). For this reason, data received later is discarded. In other words, since data is first received via the P-system transmission line 4p in the normal state, only this data is transmitted to the control data extraction unit 106, and thereafter, data transmitted via the S-system transmission line 4s is transmitted. Even if it is received, this data is discarded.

  Then, the control data extraction unit 106 extracts control data from the data previously received by the data reception unit 105, and outputs this control data to the control data calculation unit 102.

  The control data calculation unit 102 stores the process value obtained via its own plant equipment control unit 101 and the control target value data of the generated power transmitted from the master controller 1 in a predetermined data area of a memory (not shown). Arithmetic processing such as writing or preparing to transfer control data other than the control data addressed to itself to another controller 3 is executed (S22).

  Further, since the control data calculation unit 102 reads out the control target value of the generated power determined for the power generation device 12 from the memory and supplies the control target value to the plant device control unit 101, the plant device control unit 101 The generated power of the power generator 12 connected to itself is controlled based on the above.

  In addition, the control data calculation unit 102 transfers the control data such as the control target value and command value of the generated power other than addressed to itself to the other slave controller 3, and sends the control data to the transmission data creation unit 103. Send it out. At this time, status information (for example, an increment value) whose value is updated every transmission is added to the control data.

  The transmission data creation unit 103 processes the control data including the status information into a transmission form suitable for data transmission such as a packet and creates the transmission data (S23). Next, the data transmission unit 104 transmits the transmission data from the transmission paths 4p and 4s toward the other slave controller 3.

  At that time, the data transmission unit 104 transmits the transmission data having the same content to each of the transmission lines 4p and 4s with a predetermined time interval ΔT so as not to overlap each other in time. That is, for example, when the data transmission unit 104 first transmits transmission data via the P-system transmission line 4p (S24), after the time ΔT has elapsed (S25), the data having the same content is again transmitted this time. Transmission is performed via the S-system transmission line 4s (S26).

  The above operation is the same for the slave controller 3 in the next stage. Further, here, the time intervals ΔT when the master controller transmits data and when the slave controller transmits data are the same, but they do not have to be the same.

(2) When a failure occurs in a part of the transmission line When a failure occurs in one of the P-system and S-system transmission lines 4p, 4s, the slave controllers 2, 3 Only the data that has passed through one of the transmission paths 4p or 4s arrives.

  At this time, as in the case of the normal state described in (1), the data receiving unit 105 transfers only the first data received via one of the transmission paths 4p and 4s to the control data extracting unit 106 at the next stage. Send it out.

  For example, when a failure D occurs in a portion connecting the master and slave controllers 1 and 2 in the P-system transmission line 4p, the slave controller 2 sends data via the P-system transmission line 4p. However, after the predetermined time ΔT elapses, the same data can be received as the first data via the S-system transmission line 4s. Therefore, the data receiving unit 105 sends the data received via the S-system transmission path 4 s to the control data extracting unit 106.

  Since the control data extraction unit 106 extracts the control data from the data received in this way and outputs the control data to the control data calculation unit 102, the control data calculation unit 102 performs the control of the power generator 12 based on the control data. Continue control. Therefore, it is possible to reliably prevent the occurrence of a problem that the control of the power generation device 12 becomes impossible.

  When the data transmission unit 104 of the slave controller 2 transmits data to the next slave controller 3, for example, transmission data is first transmitted via the P-system transmission path 4p. Next, after the elapse of a predetermined time interval ΔT, data having the same content is transmitted again via the S-system transmission line 4s. This also applies to the case where the next slave controller 3 transmits data to the master controller 1.

  Here, the case where a failure D has occurred in a location where the master and slave controllers 1 and 2 are connected in the P-system transmission path 4p has been described as an example, but other locations in the transmission paths 4p and 4s. Since the processing operation is basically the same even when a failure occurs, detailed explanation is omitted here.

  As described above, the data transmission unit 104 of each of the controllers 1 to 3 transmits the same data to the transmission lines 4p and 4s with a predetermined time interval ΔT regardless of whether or not the transmission lines 4p and 4s have failed. On the other hand, since the data receiving unit 105 captures only the first received data, the data can be reliably transmitted / received as long as both transmission paths 4p and 4s connecting the two controllers do not fail simultaneously. Therefore, the reliability of the data to be transmitted / received is increased, and each of the controllers 1 to 3 can stably control the power generators 11 to 13, and the master controller 1 can accurately control the target values for the power generators 11 to 13. Can be calculated.

(3) When the master controller fails As described above, each of the master and slave controllers 1 to 3 transmits a value for each transmission / reception cycle when transmitting data via the transmission paths 4p and 4s. Is included in status information (for example, increment value).

  Here, in the master controller 1, when the control data calculation unit 102 breaks down, the status information included in the data transmitted through both the transmission lines 4p and 4s does not change. That is, when the control data calculation unit 102 transmits control data to the slave controllers 2 and 3, status information (for example, an increment value) whose value is updated every transmission is added to the control data. When the control data calculation unit 102 fails, the data transmission unit 104 repeatedly transmits only the same control data, and accordingly, the status information is transmitted with the same contents, and the status information does not change.

  In each of the slave controllers 2 and 3, the data receiving unit 105 sends the data received first via the transmission lines 4p and 4s to the control data extracting unit 106, and then the control data extracting unit 106 receives the received data. However, when the status information added to the extracted control data does not change, the master abnormality detection unit 107 determines that the master controller 1 has failed, and the master abnormality is detected. A detection signal is output.

  For example, as shown in the flowchart of FIG. 4, when the master abnormality detection unit 107 of the slave controller 2 detects that there is no change in status information, a master abnormality detection signal is output accordingly. This master abnormality detection signal is given to the master switching unit 108 and the abnormality response control data calculation unit 110, respectively.

  When the master switching canceling signal is not given from the master switching canceling unit 109, the master switching unit 108 makes a master declaration indicating that it has started master switching processing for becoming a master controller (S31). The master declaration is transmitted from the transmission data creation unit 103 to the data transmission unit 104 and transmitted to the other slave controllers 3. This operation is the same for the other slave controller 3 (S41).

  Here, after the controller 2 makes the master declaration, when the data receiving unit 105 receives a master declaration sent from another controller 3, the master switching cancellation unit 109 determines the priority of the controller 3 that is the notification source. And your own priority. Then, if the self priority is high, the master switching process is continued as it is. In this example, since the priority of one controller 2 is higher than the priority of the other controller 3, one controller 2 continues the master switching process as it is (S32).

  On the other hand, since the other controller 3 has a lower priority than the one controller 2, when the data receiving unit 105 receives a master declaration from the one controller 2, the master switching canceling unit 109 In response, a master switching processing stop command is given to the master switching unit 108. Therefore, the master switching unit 108 stops the master switching process in the middle even if the master declaration is made for the first time (S42).

  In each of the controllers 2 and 3 on the slave side, when the master abnormality detection signal is given from the master abnormality detection unit 107, the control data calculation unit 110 corresponding to an abnormality is obtained by the power generation devices 12 and 13 with respect to the plant equipment control unit 101. The current process value to be held is held, and arithmetic processing is executed so as to control the power generation devices 12 and 13 using the held current process value as a control target value (S33, S43). For this reason, during the period Tc from the start to the completion of the master switching process, it is possible to prevent the occurrence of problems such that the control of the power generation devices 12 and 13 becomes unstable and hunting occurs.

  Then, in the controller 2 for one slave that continues the master switching process after the master declaration, the control data calculation unit 102 is a process of the power generation device 13 obtained by the own power generation device 12 and the other slave controller 3. The value is collected (S34). Note that the master declaration is continued as it is during the master switching process period Tc from when data collection is completed until a master switching completion declaration (S35) is issued.

  When the control data calculation unit 102 is informed that the data collection of the process values of all the power generation devices 12 and 13 has been completed, the master switching unit 108 issues a master switching completion declaration (S35). The unit 102 resumes the system control as the new master controller 2 (S36). At the same time, the control data operation unit 110 corresponding to the abnormality stops the control operation. Further, the master switching completion declaration output from the master switching unit 108 is transmitted from the transmission data creating unit 103 to the data transmitting unit 104 and transmitted to the other slave controllers 3.

  In the other controller 3, when the data receiving unit 105 receives the master switching completion signal from the controller 2, the master switching completion signal is given to both the control data computing unit 102 and the abnormal time response control data computing unit 110. The control data calculation unit 102 resumes the control as the original slave (S44), and at the same time, the control data calculation unit 110 for handling an abnormality stops the control operation.

  When the failure of the controller 1 that has been operating for the master has been repaired (S51), the other controller 2 is already operating for the master, so that the repaired controller 1 is restarted. When this happens, it becomes slave (S52) and operates under the new master controller 2 (S53).

  Thus, in the plant control system of the first embodiment, it is possible to reliably prevent the occurrence of problems such as the entire power plant control system being down and the control being stopped, so that the power generators 11 to 13 can be made smoothly and smoothly. It becomes possible to control stably.

Embodiment 2. FIG.
FIG. 5 is a configuration diagram of the power plant control system in Embodiment 2 to which the plant control system of the present invention is applied.

  The power plant control system according to the second embodiment includes a plurality of (three in this example) controllers 1 to 3, and the controllers 1 to 3 are connected to each other in a bus shape via duplex transmission lines 4p and 4s. A bus type LAN is configured by connection. Moreover, the power generators 11-13 as plant equipment are individually connected to each controller 1-3. In this example, Internet LAN cables are used as the transmission lines 4p and 4s constituting the bus-type LAN in this case. In the second embodiment, data transmission / reception between the controllers 1 to 3 is performed by broadcasting.

  Among the controllers 1 to 3, one controller 1 is defined in advance as a master for normal use, and the other controllers 2 and 3 are defined as slaves. As in the first embodiment, the same data is broadcast from the controllers 1 to 3 to the respective transmission lines 4p and 4s with a predetermined time interval ΔT so as not to overlap each other in time. To do. Further, the transmission data includes status information whose value changes every transmission / reception cycle. Also in this case, the configurations of the controllers 1 to 3 are basically the same as those shown in FIG.

  In the plant control system of the second embodiment, the respective processes in the normal case, in the case where a failure has occurred in a part of the transmission lines 4p, 4s, and in the case where the master controller 1 has failed are described in the embodiment. Since it is basically the same as the case of 1, detailed description is omitted. However, in the second embodiment, since data transmission / reception between the controllers 1 to 3 is performed by broadcast, when the master controller 1 fails, all the controllers 1 to 3 cause the failure to occur. It can be detected at the same time. For this reason, the master switching process can be performed quickly.

  In the first and second embodiments, the case where the generated power plant control system is composed of three controllers 1 to 3 and power generators 11 to 13 has been described in order to facilitate understanding of the present invention. However, it goes without saying that the number of controllers and power generation devices is not limited to such a number.

  The present invention is not limited to the one applied to the power plant control system as described in the first and second embodiments, and may be applied to other plant control systems such as a production plant control system. Is possible.

It is a block diagram of the power plant control system in Embodiment 1 of this invention. It is a block diagram which shows the structure of the controller applied to the power plant control system in Embodiment 1 of this invention. 5 is a flowchart showing data transmission / reception operations of master and slave controllers when the entire system is normal in the first embodiment of the present invention. 4 is a flowchart showing the operation of each controller when a master controller fails in Embodiment 1 of the present invention. It is a block diagram of the power plant control system in Embodiment 2 of this invention.

Explanation of symbols

1 to 3 controller, 11 to 13 power generation device (plant equipment),
4p, 4s transmission line, 101 plant equipment control unit, 102 control data calculation unit,
104 data transmission unit, 105 data reception unit, 106 control data extraction unit,
107 Master abnormality detection unit, 108 Master switching unit, 109 Master switching cancellation unit,
110 Abnormal response control data calculation unit.

Claims (3)

Multiple controllers are connected to each other via a duplex transmission path to form a network, and one controller is used as a master for sequence control of the entire system, while the remaining controllers are used as slaves. A plant control system that individually controls each plant device based on data such as a control target value and a command value given from the master controller,
Each controller transmits the same content data to each transmission line with a predetermined time difference so as not to overlap each other in time, and this transmission data includes status information whose value changes every transmission / reception cycle. When the status information included in the data input via the transmission path does not change, the slave controller determines that the master controller has failed, and the slave controller A plant control system characterized in that one of them shifts to master switching processing as much as possible to become a master controller. Each controller holds the current process value obtained in the plant equipment during the period from the start to the completion of the master switching process, and sets the held current process value as a control target value to the plant equipment. The plant control system according to claim 1, wherein the plant control system is controlled. Each controller determines that one of the duplex transmission paths has failed when data having the same content does not arrive with a predetermined time difference via each transmission path, and the other The plant control system according to claim 1 or 2, wherein control of plant equipment is continued based on data sent via a transmission path.

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