Operating mode management control system and operating mode management control method

Abstract

When powering on the common control device after inspection and maintenance, this prevents the control device from being forcibly switched to manual mode, reducing the resetting load and verification work for operators, and avoiding any impact on power generation equipment due to overlooked checks. [Solution] In a system comprising a control device 100 for controlling each power generation facility and a common control device 200 for controlling equipment shared by the power generation facilities, in which a mode switching request to switch the control device 100 to manual mode is transmitted from the common control device 200 to the control device 100 immediately after the power is turned on to the common control device 200, on / off switches 14, 24 are provided on the control path that transmits the mode switching request to the control device, which can block the transmission of the mode switching request. By opening the on / off switches 14, 24 before the power is turned on to the common control device, the transmission of the mode switching request to manual mode issued immediately after the power is turned on to the common control device 200 is blocked, and the forced transition of the control device 100 to manual mode is prevented.

Description

Technical Field

[0001] The present invention relates to an operation mode management control system and an operation mode management control method capable of avoiding forced manual transition of an operation mode when a common control device is powered on in a power plant having a plurality of power generation facilities.

Background Art

[0002] In a power plant having a plurality of power generation facilities (such as boilers, turbines, makeup water facilities, etc.), a control device for controlling each power generation facility is provided for each power generation facility. In particular, for facilities shared by each power generation facility (such as makeup water pumps, fire pumps, etc.), a common control device is further installed so that it can also be controlled and managed in a central control room.

[0003] For example, in a thermal power plant, makeup water pumps are often shared and used for a plurality of power generation facilities (such as boilers and turbines) for the purpose of reducing equipment costs, saving space, improving maintenance efficiency, and the like. In such a makeup water pump, as shown in FIG. 4, the makeup water pumps 1 and 2 are controlled by a dedicated control device 100, and the operation mode can also be switched and controlled by a control signal from the central control room 200.

[0004] In the example shown in Figure 4, the control device 100 controls the makeup water pumps 1 and 2 that supply water to the plant's tanks 3 and 4. The control circuits 10 and 20 for the makeup water pumps 1 and 2 are equipped with logical AND circuits 11 and 21 that receive the following signals: an automatic mode signal which turns ON when set to automatic operation; a low water level signal which turns ON when the water level in tanks 3 and 4 falls below a predetermined value α and then rises above a predetermined value β; a high water level signal which turns OFF when the water level in tanks 3 and 4 rises above a predetermined value β (β>α) and then falls below a predetermined value α, and turns ON otherwise; an operation continuation signal which turns ON when no stop operation is performed; and an automatic mode command signal which turns ON when an automatic mode command is issued from the common control device 200. Based on these signals, if the logical AND conditions are met, the automatic operation of each makeup water pump 1 and 2 is continued.

[0005] The common control device 200 has a function to request a switch to either an "automatic mode," which automatically controls the operating mode of the control device 100 according to the equipment status, or a "manual mode," which allows an operator to manually control the equipment based on their assessment of its status, based on a command from the central control room 300 connected to it via a communication network N. In other words, when an automatic mode command signal 34 is input from the central control room 300, the output state of that signal is held by a self-holding circuit (a circuit composed of a logical OR circuit 31 and a wipe-out circuit 32) 33 and transmitted to the control device 100 (the ON state of the command signal (automatic mode command signal) that sets the control of the makeup water pumps 1 and 2 to automatic mode is maintained). Also, when a manual mode command signal 35 is input from the central control room 300, the output of the automatic mode command signal is stopped, and the automatic mode control of the makeup water pumps 1 and 2 is canceled.

[0006] In such a common control device 200, when performing inspections or maintenance, the common control device 200 is temporarily stopped (powered off), and the power is turned back on after the inspection or maintenance is completed. However, anticipating the possibility that the equipment may exceed the control range and become unable to perform automatic control when the power is turned on, the common control device 200 is designed to issue a request to forcibly switch the control of the makeup water pump by the control device 100 to "manual mode" when the power is turned on (the manual mode command signal 35 is input to the wipe-out circuit 32 of the self-holding circuit 33 of the common control device 200, and the automatic mode command signal is blocked). [Overview of the Initiative] [Problems that the invention aims to solve]

[0007] Incidentally, from the perspective of adjusting the supply and demand of electricity, if it is practically difficult to shut down all power generation equipment when performing maintenance, including periodic inspections and replacements of the common control device 200, the inspection and maintenance of the common control device 200 may be carried out while the power generation equipment (makeup water pump) is operating in automatic mode.

[0008] Therefore, in such cases, if the common control device 200 is temporarily stopped (powered off) for inspection and maintenance, and then powered back on after the inspection and maintenance are completed, the common control device 200 will issue a request to switch to manual mode at that point, the transmission of the automatic mode command signal that had been maintained until then will stop (be disabled), and the makeup water pump that was operating in "automatic mode" will be forced to switch to "manual mode" and enter standby mode, resulting in the inconvenience of interrupting automatic control.

[0009] Operators check the status of each piece of equipment at the end of inspections, but there are many items to check, and if they forget to check something and miss the fact that the system has switched to manual mode, that state will remain. As a result, the supply of water by the makeup water pump will stop, the tank will become empty, and problems that affect the plant may occur.

[0010] This invention has been made in view of the above circumstances, and its main objective is to provide an operating mode management control system and an operating mode management control method that can prevent the control device from being forcibly switched to manual mode when power is turned on after inspection and maintenance of the common control device, thereby reducing the resetting load and verification workload for operators, and avoiding the impact on power generation equipment due to overlooked verification. [Means for solving the problem]

[0011] To achieve the above objectives, the present invention provides an operating mode management control system, A control device for controlling the power generation equipment, The system includes a common control device that controls equipment shared by the aforementioned power generation equipment, In an operating mode management control system having a configuration in which a mode switching request for switching the control device to manual mode is transmitted from the common control device to the control device immediately after the power is turned on of the common control device, A switch is provided on the control path that transmits the mode switching request to the control device, which can block the transmission of the mode switching request. It is characterized by the following.

[0012] Therefore, by turning off the power to the common control unit for inspection or maintenance, and then opening the on / off switch before turning on the power to the common control unit after the inspection or maintenance is complete, it is possible to prevent the control circuit from receiving a request to switch to manual mode from the common control room after the power to the common control unit has been turned on. This makes it possible to avoid the inconvenience of disrupting the automatic control of the power generation equipment when it is in continuous operation.

[0013] Here, the on / off switch may be operated manually, but it may also be configured to open automatically before the power supply to the common control device is turned on, and to close automatically after the power supply to the common control device is turned on, subject to confirmation that the power generation equipment is in a normal state. This configuration avoids the inconvenience caused by forgetting to open the on / off switch when the common control unit is powered off, and also prevents problems when restoring to automatic mode after the common control unit is powered on.

[0014] Furthermore, the power generation equipment is a makeup water pump, and the on / off switch is preferably installed in the control device (control panel) that controls the makeup water pump. By installing the on / off switch in the control device of the makeup water tank being controlled, the on / off switch can be managed individually for each control device, so that only the control device in question can be operated individually in the event of an abnormality or maintenance, thereby minimizing the impact on other devices. In addition, this configuration avoids the inconveniences of complicated wiring and operation that may occur when the on / off switch is installed in a common control device, thereby improving the reliability and operability of the entire system. [Effects of the Invention]

[0015] As described above, according to the operating mode management control system of the present invention, by installing an on / off switch capable of blocking signal transmission in the transmission path that transmits mode switching requests from a common control device to a control device, and by opening the on / off switch before the power is turned on to the common control device, the transmission of a request to switch to manual mode issued immediately after the power is turned on to the common control device is prevented, and it becomes possible to prevent the control device from being forcibly switched to manual mode. This reduces the resetting load and verification workload for operators, and makes it possible to avoid the impact on power generation equipment due to overlooked verifications. [Brief explanation of the drawing]

[0016] [Figure 1] This diagram shows the overall configuration of the operating mode management control system according to the present invention, and is a diagram showing the state in which the on / off switch is closed. [Figure 2] This diagram shows the overall configuration of the operating mode management control system according to the present invention, and is a diagram showing the state in which the on / off switch is opened. [Figure 3] This flowchart shows the process from inspection and maintenance to returning to normal control. [Figure 4] This is a diagram showing the overall configuration of a conventional operation mode management control system.

Best Mode for Carrying Out the Invention

[0017] Hereinafter, embodiments of the present invention will be described based on the drawings. In FIG. 1, a control system S for controlling makeup water pumps 1 and 2 as power generation facilities is shown. This control system S has a control device (control panel) 100 provided with respective control circuits 10 and 20 for controlling a plurality of makeup water pumps (first makeup water pump 1 and second makeup water pump 2). Since these makeup water pumps 1 and 2 are also facilities shared by each power generation facility in the power plant, they are also controlled by a common control device 200 that switches and controls their operation modes.

[0018] Logic circuits for on / off control of the makeup water pumps 1 and 2 are incorporated in the respective control circuits 10 and 20. In this example, the makeup water pumps 1 and 2 are designed to be activated by logic product circuits (AND circuits) 11 and 21 when all of the following four conditions (C1 to C4) are satisfied (when turned on), and automatic operation is performed (that is, it operates when the logic product condition is satisfied). Condition 1 (C1): The makeup water pump is set to automatic operation manually. When set to automatic operation, the signal becomes ON. Condition 2 (C2): The water levels in tanks 3 and 4 are below a predetermined value α. When the tank water level drops below the predetermined value α, the low water level signal becomes ON, and then the signal remains ON until it recovers to a value equal to or greater than a predetermined value β (β > α). Condition 3 (C3): The water levels in tanks 3 and 4 are less than a predetermined value β. When the tank water level becomes equal to or greater than the predetermined value β, a high water level signal is issued, but the signal becomes OFF by the inversion circuits 12 and 22 until the tank water level drops below the predetermined value α again, and becomes ON in other cases. Condition 4 (C4): A stop operation is not being performed. When a stop operation is not being performed, the operation continuation signal becomes ON.

[0019] Therefore, assuming that the makeup water pumps 1 and 2 are set to the automatic mode and no stop operation is performed, when the water level levels in the tanks 3 and 4 decrease and reach below a predetermined value α, the low water level signal turns ON, and the makeup water pumps 1 and 2 automatically start operating to supply water to the tanks 3 and 4 to raise the water level. While the makeup water pumps 1 and 2 are operating, the low water level signal remains ON until the water level level in the tanks 3 and 4 reaches above a predetermined value β. Thereafter, when the water level level in the tanks 3 and 4 reaches the predetermined value β, the high water level signal is inverted to OFF, and since a part of the operating conditions of the makeup water pumps 1 and 2 is released, the operation of the makeup water pumps 1 and 2 stops. Thereafter, when the water in the tank is consumed and the water level levels in the tanks 3 and 4 decrease again below the predetermined value α, the low water level signal turns ON again, and the high water level signal also turns ON. As a result, the makeup water pumps 1 and 2 restart to supply the water level up to above the predetermined value β again. By this series of operations, the water level in the tank is stably maintained within a predetermined range (within the range of α and β).

[0020] In the AND circuits 11 and 21 of the control circuits 10 and 20 described above, a control signal from the common control device 200 is also input, and the operation and stop of the makeup water pumps 1 and 2 are also determined by an operation mode switching signal for switching the operation mode from the common control device 200.

[0021] The common control device 200 includes a self-holding circuit 33 composed of an OR circuit 31 and a wipe-out circuit 32. Based on a command from the central control room 300 connected via the communication network N, when a one-shot automatic mode command signal 34 is input, the output state of the signal is maintained by the self-holding circuit 33 and supplied to the control circuits 10 and 20 of the makeup water pumps 1 and 2. Also, when a one-shot manual mode command signal 35 is input based on a command from the central control room 300, the output of the automatic mode command signal stops, and the supply of the automatic mode command signal to the makeup water pumps 1 and 2 is released.

[0022] The control path from the self-holding circuit 33 of the common control device 200 to the AND circuits 11 and 21 of each control circuit 10 and 20 includes an inverting circuit 36 ​​provided on the common control device 200 side, inverting circuits 13 and 23 provided on the control circuit side, and on / off switches 14 and 24 provided on the control device 100, which are positioned between these inverting circuits (between 36 and 13, and between 36 and 23).

[0023] The inverting circuits 36, 13, and 23 are provided to ensure logic level consistency, signal stabilization, signal synchronization and timing adjustment between devices, and correct transmission of signals sent from the self-holding circuit 33.

[0024] The on / off switches 14 and 24 are, but are not limited to, equipped with regular contacts 14a and 24a that connect the common control device 200 to the control device 100, except when the power to the common control device 200 is temporarily turned off for inspection, maintenance, etc., and inspection contacts 14b and 24b that disconnect the common control device 200 from the control device 100 when the power to the common control device 200 is temporarily turned off for inspection, maintenance, etc.

[0025] In the above configuration, as shown in Figure 1, when the open / close switches 14 and 24 are set to the normal contact side and the common control device 200 is connected to the control device 100, when an automatic mode command signal 34 is input in one shot from the central control room 300 to the self-holding circuit (a circuit composed of a logical OR circuit 31 and a wipe-out circuit 32) 33 of the common control device 200, the following series of operations are performed.

[0026] (1) Signal retention on the common control device side When an automatic mode command signal is input from the central control room 300 in a single shot, a self-holding circuit 33, consisting of a logical OR circuit 31 and a wipe-out circuit 32, located within the common control device 200, captures the input signal and holds its output state. Due to this holding operation, once an automatic mode command signal is input, it will continue to be output unless specific conditions occur, such as a manual mode command signal from the central control room 300 or a power outage of the common control device 200.

[0027] (2) Signal transmission via inverting circuit and on / off switch The automatic mode command signal held by the self-holding circuit 33 first passes through the inverting circuit 36 ​​provided on the common control device 200 side. Here, the signal is inverted to the appropriate logic level according to the requirements of the subsequent circuit design. After this inverted signal is sent to the on / off switches 14 and 24 on the control path to the control device 100 side. Since the on / off switches 14 and 24 are set to the normal contacts 14a and 24a that normally connect the common control device 200 to the control device 100, signals from the common control device 200 are transmitted to the control circuits 10 and 20 of the control device 100 without interruption. The signals that have passed through the on / off switches 14 and 24 are input to the inversion circuits 13 and 23 provided on the control device 100 side, where the signals are inverted again. As a result, the "automatic mode command signal" issued from the common control device 200 is converted to the necessary logic state and input to the AND circuits 11 and 21 within the control device.

[0028] (3) The conditions for AND circuit input within the control panel are met. The control device 100 incorporates logic for turning the makeup water pumps 1 and 2 on and off. The AND circuits 11 and 21 turn on when all input conditions are met (when all conditions are 1). This starts the makeup water pumps (first makeup water pump 1 and second makeup water pump 2) and begins supplying makeup water to tanks 3 and 4.

[0029] (4) Pump on / off control in response to water level fluctuations: When the supply water pumps 1 and 2 are activated, the water levels in tanks 3 and 4 begin to rise. When the water level in tanks 3 and 4 rises to a predetermined value β or higher, the stop condition based on the high water level is met in the logic circuit, and some of the conditions in the AND circuits 11 and 21 are broken, causing the supply water pumps 1 and 2 to turn off. Subsequently, when the water level in tanks 3 and 4 falls again to a predetermined value α or lower, all the conditions in the AND circuits 11 and 21 are met again, and the pumps turn on. Due to this hysteresis characteristic (on when the predetermined value α is below, and off when β is above), the pump automatically switches on and off repeatedly while the water level in the tank is fluctuating. What is important here is that as long as the automatic mode command signal from the self-holding circuit 33 of the common control device 200 is maintained, this automatic control cycle is repeated, and the makeup water pumps 1 and 2 switch on and off as needed to maintain a stable tank water level.

[0030] (5) Disable automatic mode by inputting a manual mode command signal. On the other hand, when a manual mode command signal 35 is input from the central control room 300, the wipe-out circuit 32 on the common control device 200 side operates, and the output of the automatic mode command signal that had been held up until then is cleared. As a result, the transmission of the automatic mode command signal from the self-holding circuit 33 stops, and the logical AND circuit condition of the control device 100 is no longer met. Consequently, even if tanks 3 and 4 are at a low water level and the operation of the makeup water pumps 1 and 2 is required, the "automatic mode command signal" is no longer transmitted from the common control device 200 side, so the makeup water pumps 1 and 2 remain off.

[0031] Incidentally, in the above configuration, when the on / off switches 14 and 24 are set to the normal operation side and the common control device 200 is connected to the control device 100, when power is turned on after inspection and maintenance of the common control device 200, a manual mode command signal 35 is input in one shot to the self-holding circuit 33 of the common control device 200 by command from the central control room 300 for the purpose of safety checks and initial adjustments when starting up the power generation equipment and related systems. As a result, the following problems may occur.

[0032] In other words, when a manual mode command signal 35 is input to the self-holding circuit 33 in a single shot by command from the central control room 300, the wipe-out circuit 32 within the self-holding circuit 33 operates, and the output of the previously held automatic mode command signal is forcibly cleared. As a result, the transmission of the automatic mode command signal from the common control device 200 to the control device 100 is interrupted. At this point, the ON state of the automatic mode command signal from the common control unit, which is one of the logical AND circuit conditions of the control unit 100, is lost. As a result, even in the control circuit that had been operating the makeup water pumps 1 and 2 in automatic mode, the makeup water pumps 1 and 2 will not operate even when the water level in tanks 3 and 4 drops and a situation arises where replenishment by the makeup water pumps 1 and 2 is actually necessary. Consequently, the makeup water pumps 1 and 2 remain stopped, and the necessary water supply is not provided. This situation means that the necessary water supply to each power generation facility is interrupted, which reduces functions such as cooling and lubrication, and increases the risk from the standpoint of protecting the equipment.

[0033] Therefore, before the common control device 200 is started (before the power is turned on), the on / off switches 14 and 24 are switched to the inspection contacts 14b and 24b side, as shown in Figure 2 (the on / off switches 14 and 24 are closed). The on / off switches 14 and 24 may be opened manually, or they may be opened automatically when the power to the common control device 200 is turned off. This prevents the common control device 200 from receiving a signal indicating that it has been powered on and the automatic mode command signal has been stopped (resulting in the issuance of a request to switch to manual mode), and this signal is then transmitted to the control device 100.

[0034] The process from inspecting and maintaining the common control unit 200 to returning it to normal control is summarized below (see Figure 3).

[0035] (1) Inspection and maintenance of the common control unit (Step S01) The common control unit 200 is inspected and maintained while powered off. During this time, the makeup water pumps 1 and 2 may be operating automatically in automatic mode.

[0036] (2) Preparations before restarting the common control unit (Step S02) Before power is restored to the common control unit 200, the on / off switches 14 and 24 installed on the signal transmission path from the common control unit 200 to the control unit 100 are switched from the "normal contact" side (used during normal operation) to the "inspection contact" side. This operation ensures that the request to switch to manual mode (blocking the automatic mode command signal) issued by the common control device 200 during the startup sequence is not directly transmitted to the control device 100.

[0037] (3) Power on the common control unit (Step S03) With the on / off switches 14 and 24 in the inspection contact position, power is supplied to the common control device 200. At this time, initialization is performed inside the common control device 200, and a manual operation request signal may be input from the central control room 300 in a single shot. However, this signal is not transmitted to the control device 100 side because it is interrupted by the fact that the on / off switches 14 and 24 are set to inspection contacts 14b and 24b. Therefore, the automatic mode command signal is cleared within the common control device 200, but at that point, it does not affect the makeup water pump control logic of the control device 100 (even if the manual mode command signal 35 is input, the operation of clearing the automatic mode command signal by the self-holding circuit 33 is completed within the common control device 200, and the request to switch to manual mode is not transmitted to the control device 100, thus avoiding a forced transition to manual mode and resolving the previously occurring problem).

[0038] In other words, conventionally, when inspecting and maintaining the common control device 200, the power to the common control device 200 is temporarily turned off, and then when the inspection and maintenance is completed and the power is turned back on, a manual mode command signal 35 from the central control room 300 is input in a single shot. As a result, the automatic mode command signal, which had been maintained by the self-holding circuit 33, is cleared, and the makeup water pump, which has been operating in automatic mode even during the inspection and maintenance of the common control device 200, is forcibly switched to manual mode. This prevents automatic water supply at the necessary time, and there were concerns about the impact on the power generation equipment due to a drop in the tank water level. In contrast, in this embodiment, on / off switches 14 and 24 are installed on the transmission path of the operating mode switching signal from the common control device 200 to the control device 100. By switching these on / off switches 14 and 24 to the inspection side (inspection contacts 14b and 24b) before powering on the common control device 200, even if a manual mode command signal 35 is input to the self-holding circuit 33 immediately after powering on the common control device 200, the signal is not transmitted to the control device 100 at that time. As a result, the operating state of the makeup water pumps 1 and 2, which are operating in automatic mode, is maintained at this stage (the state of repeatedly turning on and off at the necessary timing is maintained).

[0039] (4) Confirmation of normal state (Step S04) After inspection and maintenance, the power generation equipment and related facilities (such as tanks) are confirmed to be in normal condition by operators or an automated detection mechanism.

[0040] (5) Return to normal connection and reissue of autonomous driving request (Step S05) Once it is confirmed that the equipment is functioning correctly, the operator returns the on / off switches 14 and 24 to the "normal contact" side (closes the on / off switches 14 and 24). Closing the on / off switches 14 and 24 may be done manually, but it may also be done automatically after the power to the common control device 200 is turned on and the normal state of the power generation equipment is confirmed. This ensures that signals from the common control unit 200 are properly transmitted to the control unit 100. Next, the central control room 300 issues an automatic operation request signal again. As a result, the automatic mode command signal 34 is transmitted to the control unit 100 via the common control unit 200, and the makeup water pumps 1 and 2 resume automatic on / off control according to the tank water level. Here, the on / off switches 14 and 24 may be configured to automatically close when conditions are met indicating that the power generation equipment and related equipment are functioning normally, and to automatically issue an automatic mode command signal from the central control room 300.

[0041] (6) Transition to normal control state (Step S06) This series of procedures ensures that the common control unit 200 safely and reliably returns to its normal automatic operation mode after inspection and maintenance. As a result, the makeup water pump automatically starts and stops according to the tank water level, and a stable supply of makeup water to the power generation equipment is resumed.

[0042] Therefore, by avoiding forced transition to "manual" mode through the above procedure, the resetting and verification work after inspection and maintenance is greatly reduced. Conventionally, if the system switched to manual mode, the operator had to perform operations to return to "automatic" mode, check the status of the equipment, and reset the operating conditions. Furthermore, there was a possibility of oversight (failure to check) during these verification tasks, which posed a risk of affecting the power generation equipment (such as a drop in tank water level). However, with the present invention, it is possible to greatly reduce such risks and the workload of the operator through the operation of the on / off switches 14 and 24, and to reduce the risk of affecting the power generation equipment (such as a drop in tank water level).

[0043] In the above configuration, the mode switching request to switch the control device 100 to manual mode immediately after power-on of the common control device 200 was obtained by wiping out the automatic mode command signal (blocking the transmission of the automatic mode command signal). However, this system may also be similarly adopted for configurations in which the manual mode command signal is directly transmitted to the control circuit 100 as the mode switching request. Furthermore, while a makeup water pump was used as an example of power generation equipment, this system can also be similarly adopted for fire extinguishing pumps and other power generation equipment where a forced transition to manual mode when the common control device is powered on becomes problematic. [Explanation of Symbols]

[0044] 1,2 Water supply pump 14,24 On / Off Switch 100 Control device 200 Common Control Device

Claims

1. A control device for controlling the power generation equipment for each power generation equipment, The system includes a common control device that controls equipment shared by the aforementioned power generation equipment, In an operating mode management control system having a configuration in which a mode switching request for switching the control device to manual mode is transmitted from the common control device to the control device immediately after the power is turned on of the common control device, An operating mode management control system characterized in that an on / off switch is provided on the control path that transmits the mode switching request to the control device, which can block the transmission of the mode switching request.

2. The operating mode management control system according to claim 1, characterized in that the on / off switch is automatically opened before the power supply to the common control device is turned on, and is automatically closed after the power supply to the common control device is turned on, subject to confirmation that the power generation equipment is in a normal state.

3. The operating mode management control system according to claim 1 or 2, characterized in that the power generation equipment is a makeup water pump, and the on / off switch is provided in a control device that controls the makeup water pump.

4. A method using the operating mode management control system described in claim 1, A control method for managing operating modes, characterized in that an on / off switch provided on the control path is opened before the power is turned on to the common control device.

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