JP7107763B2 - Multiplexed servo control system, multiplexed servo control method, and power generation system - Google Patents

Description

The present invention relates to a multiplexed servo control system, a multiplexed servo control method, and a power generation system.

The output of a generator in a power plant is controlled by adjusting the flow rate of steam supplied to a steam turbine according to the degree of opening of a steam control valve and a steam stop valve (servo valve). Servo valves used in thermal power plants and nuclear power plants are required to be highly reliable, so servo modules, which are control mechanisms for driving the servo valves, are multiplexed (for example, Patent Document 1).

Japanese Unexamined Patent Application Publication No. 2003-148108

When the servo modules are multiplexed in preparation for the occurrence of an abnormality in each servo module, there is a possibility that the control logic will become complicated and the cost will increase. In addition, it is necessary to determine which of the multiplexed servo modules is causing the abnormality, and replace the abnormal servo module appropriately to restore stable operation of the multiplexed system. There is room for improvement. Therefore, it is required to improve the accuracy of abnormality detection of each servo module and the safety of restoration of the servo module after the abnormality detection, and to suppress the unstable operation of the servo valve.

SUMMARY OF THE INVENTION The present invention has been made in view of such circumstances, and aims to provide a multiplexed servo control system, a multiplexed servo control method, and a power generation system capable of suppressing unstable operation of servo valves. aim.

A first aspect of the present invention provides a servo unit having a plurality of servo modules for outputting drive opening signals to the servo valves based on opening commands for predetermined servo valves, and performing an abnormality determination for each of the servo modules. each of the servo modules includes a measurement unit that measures the degree of opening of the servo valve; and a determination of the degree of opening to the servo valve based on the degree-of-opening command and the degree of opening measured by the measurement unit. a driving unit that outputs the drive opening signal, and the abnormality determination unit includes an abnormality detection unit that detects an abnormality in each of the measurement units; A multiplexed servo control system, comprising: a judgment unit for judging whether or not there is an abnormality in each servo module based on the deviation between the servo modules and the detection result of the abnormality detection unit.

According to the configuration as described above, the multiplexed servo module is determined based on the deviation of the measurement result of each opening in the measurement unit that measures the opening of the servo valve and the detection result of the abnormality of the measurement unit itself. Since the abnormality determination is performed, it is possible to more accurately identify the servo module in which the abnormality has occurred. For example, if the number of installed servo modules is 3 (triple servo module), if an abnormality occurs in one of them, the deviation between the measurement results of each opening degree of the measuring part of each servo module will be Based on this, it is possible to specify in which servo module the abnormality has occurred. However, if an abnormality occurs in two of the tripled servo modules, the servo module in which the abnormality has occurred cannot be specified only by the deviation of the measurement result of each opening of the measurement unit of each servo module. . Therefore, by paying attention to the measurement unit in which an abnormality is likely to occur in the servo module and also considering the detection result of the abnormality of the measurement unit itself, even if an abnormality occurs in two of the triplets, It becomes possible to specify the servo module in which the abnormality has occurred. Therefore, it is possible to improve the accuracy of abnormality determination of multiplexed servo modules.

In the above-described multiplexed servo control system, the determination unit determines if the difference between the measurement result of the measurement unit in the arbitrarily selected servo module and the measurement result of the measurement unit in the other servo module is equal to or greater than a predetermined value. and when the abnormality of the measuring section in the arbitrarily selected servo module is detected by the abnormality detecting section, an abnormality occurs in the arbitrarily selected servo module. It may be determined that

According to the configuration as described above, even if an abnormality occurs in a plurality of servo modules in the multiplexed servo modules, it is possible to identify the servo module in which the abnormality has occurred, thereby improving the accuracy of abnormality determination. can be made

In the above multiplexed servo control system, the abnormality determination unit may have a stop unit for stopping output of the drive opening signal to the servo valve by the servo module determined to be abnormal in the determination unit. good.

According to the above configuration, since the output of the drive opening signal for the servo valve by the servo module determined to be abnormal is stopped, the normal servo module can stably send the drive opening signal to the servo valve. can be output. That is, the servo valve can be continuously operated stably.

In the multiplexed servo control system, when the opening command value in the servo module and the opening command are the same when the servo module determined to be abnormal by the determination unit is restored, It is also possible to provide a return control section for canceling stop control in the stop section.

According to the above configuration, when the servo module determined to be abnormal is to be restored (cancel the stop control), the opening command value in the servo module determined to be abnormal is the opening degree from the command unit. Since the condition is that the value is the same as the command value, the servo module does not output until the output signal stabilizes at the time of recovery. The servo module can be waked up. Here, "same" means that the openings match within a predetermined range (for example, within ±2%).

A second aspect of the present invention provides a servo unit having a plurality of servo modules for outputting drive opening signals to the servo valves based on opening commands for predetermined servo valves, and performing an abnormality determination for each of the servo modules. an abnormality determination unit for stopping the output of the opening signal for driving the servo valve by the servo module determined to be abnormal; and when the servo module determined as abnormal by the abnormality determination unit is restored, the servo a return control unit that cancels stop control of the servo module determined to be abnormal by the abnormality determination unit when the opening command value in the module and the opening command are the same. Servo control system.

According to the configuration described above, when the servo module determined to be abnormal is to be restored (cancel the stop control), the opening command value in the servo module determined to be abnormal and the opening command are the same. Since the condition is set to be, the servo module can be returned stably. For example, when a servo module is determined to be abnormal and stop control is executed, reset processing, part replacement processing, or the like may be performed on the servo module determined to be abnormal. In such a case, the opening command value in the servo module that has been determined to be abnormal may be the initial value (for example, 0). It may become a cause of failure. Therefore, the servo module determined to be abnormal is not returned to normal state until the opening command value in the servo module matches the opening command. Therefore, it is possible to prevent the control of the servo valve from becoming unstable.

In the above multiplexed servo control system, each of the servo modules includes a measurement unit that measures the opening of the servo valve, and a command to the servo valve based on the opening command and the opening measured by the measurement unit. and a driving unit that outputs a drive opening signal, and the abnormality determination unit includes an abnormality detection unit that detects an abnormality in each of the measurement units, and a deviation between measurement results measured by each of the measurement units. and a determination unit that determines whether or not there is an abnormality in each of the servo modules based on the detection result of the abnormality detection unit.

According to the configuration as described above, the multiplexed servo module is determined based on the deviation of the measurement result of each opening in the measurement unit that measures the opening of the servo valve and the detection result of the abnormality of the measurement unit itself. Since the abnormality determination is performed, it is possible to more accurately detect in which servo module the abnormality has occurred.

In the above multiplexed servo control system, a plurality of command units for outputting the opening command for the servo valve are provided, and the command units are synchronized with each other so as to output the same opening command. good too.

According to the above configuration, since the command units that output opening commands to the servo valves are synchronized with each other, it is possible to prevent the opening command output from each command unit from becoming a different signal. . Note that the command unit is, for example, an information processing device such as a CPU.

In the above multiplexed servo control system, each of the servo modules may be provided with no means for confirming synchronization with each other.

According to the configuration as described above, synchronization between the servo modules is not checked, so control logic for synchronizing the servo modules can be omitted, and the system can be simplified and the cost can be reduced. It becomes possible.

A third aspect of the present invention is a measurement unit for measuring a predetermined opening degree of a servo valve, and an opening degree for driving the servo valve based on an opening command for the servo valve and the opening degree measured by the measurement unit. A multiplexed servo control method for a plurality of servo modules having a drive unit for outputting a signal, comprising: an abnormality detection step of detecting an abnormality in each measuring unit; and a deviation between measurement results measured by each measuring unit. and a determination step of determining whether or not there is an abnormality in each of the servo modules based on the detection result of the abnormality detection step.

A fourth aspect of the present invention is a multiplexed servo control method for a plurality of servo modules for outputting drive opening signals to the servo valves based on opening commands for predetermined servo valves, wherein each of the servo modules an abnormality determination step of performing an abnormality determination and stopping output of an opening signal for driving the servo valve by the servo module determined to be abnormal; and restoring the servo module determined to be abnormal by the abnormality determination step. a return control step of canceling stop control of the servo module determined to be abnormal by the abnormality determination step when the opening command value in the servo module and the opening command are the same; A multiplexed servo control method comprising:

A fifth aspect of the present invention is a power generation system comprising the above multiplexed servo control system.

ADVANTAGE OF THE INVENTION According to this invention, it is effective in the ability to suppress the unstable operation of a servo valve.

1 is a diagram showing a schematic configuration of a power generation system equipped with a multiplexed servo control system according to one embodiment of the present invention; FIG. 1 is a diagram illustrating the configuration of a turbine steam control valve according to an embodiment of the present invention; FIG. 1 is a functional block diagram showing functions provided in a multiplexed servo control system according to one embodiment of the present invention; FIG. It is the figure which showed the schematic structure of the internal structure of the measurement part which concerns on one Embodiment of this invention. It is the figure which showed the electrical equivalent circuit of the measurement part which concerns on one Embodiment of this invention. It is a conceptual diagram which shows the abnormality determination process of the determination part which concerns on one Embodiment of this invention. FIG. 4 is a diagram illustrating servo module opening command values when an abnormality occurs in the multiplexed servo control system according to one embodiment of the present invention; FIG. 4 is a diagram showing a flow chart of processing in the multiplexed servo control system according to one embodiment of the present invention;

An embodiment of a power generation system having a multiplexed servo control system according to the present invention will be described below with reference to the drawings. In the present embodiment, a case where the multiplexed servo control system 8 is used in the power generation system 1 will be described, but it can be applied in the same manner as long as it is a system or equipment provided with a valve that requires control of the opening degree. be.
FIG. 1 is a diagram showing a schematic configuration of a power generation system 1 equipped with a multiplexed servo control system 8 according to one embodiment of the present invention. As shown in FIG. 1, a power generation system 1 according to the present embodiment includes a boiler 2, a steam turbine 3, a generator 4, a condenser 5, a feedwater pump 6, a turbine steam control valve 7, a multiplex It is equipped with a servo control system 8 as a main configuration. Note that the multiplexed servo control system 8 can be applied without being limited to the above configuration as long as the power generation system 1 includes the turbine steam control valve 7 (at least one of the stop valve 11 and the control valve 12).

The multiplexed servo control system 8 is provided for both the stop valve 11 and the control valve 12 that constitute the turbine steam control valve 7. The multiplexed servo control system 8 will be described.

The boiler 2 converts boiler feedwater sent from the feedwater pump 6 into superheated steam in the boiler 2 and supplies the superheated steam to the steam turbine 3 . Specifically, the boiler 2 includes an economizer, an evaporator, a superheater, and the like. Boiler feed water is first heated by an economizer and becomes saturated steam in an evaporator tube. After that, it becomes superheated steam by being further superheated in the superheater. Superheated steam generated by the boiler 2 is supplied to the steam turbine 3 via the turbine steam control valve 7 . In addition, the configuration of the boiler 2 is such that heat is exchanged between the combustion gas that is supplied with fuel and burned in the furnace and boiler water supplied to the boiler 2, and the high temperature exhaust gas from the gas turbine or the like to the boiler 2. There are those that exchange heat with the boiler feed water, etc., and not limited to the above, but various configurations can be adopted and are not limited.

The steam turbine 3 (hereinafter simply referred to as "turbine 3") is supplied with superheated steam generated in the boiler 2, and the superheated steam expands to rotationally drive the turbine blades. That is, the turbine 3 converts the energy of superheated steam into rotational energy. As the configuration of the turbine 3, various configurations such as a three-stage configuration of a high-pressure turbine, an intermediate-pressure turbine, and a low-pressure turbine, and a two-stage configuration of a high-pressure turbine and a low-pressure turbine can be applied, and the configuration is not limited. A rotating shaft of the turbine 3 is connected to a generator 4 , and rotational energy converted by the turbine 3 is transmitted to the generator 4 .

The generator 4 is rotationally driven by the turbine 3 and generates power using rotational energy generated by the turbine 3 . Electricity generated by the generator 4 is supplied to the electric power system via, for example, a booster or the like.

The condenser 5 cools the steam that has finished working in the turbine 3 (steam discharged from the turbine 3), returns it to a liquid phase, and condenses it. Specifically, the condenser 5 is provided with heat transfer tubes to which cooling water such as seawater is supplied, and steam discharged from the turbine 3 flowing outside the heat transfer tubes and steam flowing inside the heat transfer tubes Heat exchange takes place with cooling water. That is, in the condenser 5, cooling water is used to cool the steam discharged from the turbine 3 to generate condensed water. The generated condensate is supplied to the water supply pump 6 via a heater (not shown) and a deaerator (not shown).

The feedwater pump 6 pumps the supplied condensate to the boiler 2 as boiler feedwater. By controlling the water supply pump 6, it is possible to control the flow rate of the boiler water supply supplied to the boiler 2, and the like. Further, the boiler water supply supplied from the water supply pump 6 may be supplied to the boiler 2 after being further heated by a high-temperature heater (not shown).

A turbine steam control valve 7 controls the flow rate of steam supplied from the boiler 2 to the turbine 3 . By controlling the flow rate of steam, it is possible to control the rotational power of the turbine 3 and the like, thereby controlling the output (generated power) of the generator 4 . The turbine steam control valve 7 of this embodiment is composed of a stop valve 11 and a control valve 12 . FIG. 2 is a diagram (longitudinal sectional view) illustrating the configuration of the turbine steam control valve 7. As shown in FIG. As shown in FIG. 2, the steam produced by the boiler 2 is supplied to the turbine 3 via the turbine steam control valve 7 (stop valve 11 and control valve 12). In this embodiment, as shown in FIG. 2, the case where the stop valve 11 and the control valve 12 are integrally configured will be described. good too.

By controlling the degree of opening of the stop valve 11, the flow rate of steam passing through the turbine steam control valve 7 can be made zero (stopped). That is, the stop valve 11 is a valve that performs an opening/closing function in the turbine steam control valve 7 . The stop valve 11 has a first-opening valve (not shown) that does not allow a small amount of steam to pass through (that is capable of controlling a small amount of steam), and controls the opening of the first-opening valve. By doing so, the steam flow rate can be controlled.

The control valve 12 (governor valve) can adjust the flow rate of steam in a load increase that increases the rotational power of the turbine 3 by controlling the opening degree of the valve. That is, in the turbine steam control valve 7, the stop valve 11 reliably stops the steam supplied to the turbine 3, and the control valve 12 controls the flow rate of the steam supplied from the boiler 2 to the turbine 3 required for power generation. ing.

The stop valve 11 is controlled by a stop valve driver 11a. Specifically, the piston shaft 11b is controlled by the stop valve driver 11a, and the opening degree of the stop valve 11 is adjusted via the link mechanism 11c connected to the piston shaft 11b. For example, when the piston shaft 11b is controlled in the direction of arrow D1 by the stop valve driver 11a, the drive is transmitted to the stop valve 11 via the link mechanism 11c, and the stop valve 11 operates in the direction of arrow D1. It will open (the degree of opening will be fully open). The control valve 12 also has a driving mechanism similar to that of the stop valve 11, and the opening degree of the valve is controlled by a control valve driver 12a. For example, when the piston shaft 12b is controlled in the direction of the arrow D2 by the control valve driver 12a, the control valve 12 operates in the direction of the arrow D2 via the link mechanism 12c, and the opening is controlled and opened (opening becomes larger). The drive mechanism of the stop valve 11 and the control valve 12 shown in FIG. 2 is an example, and it is also possible to control each valve by other methods.

The stop valve driver 11a and the control valve driver 12a are each composed of a servo coil 26 and a hydraulic drive device 27, as shown in FIG. A hydraulic drive device 27 is operated by a servo coil 26 to move the piston shaft (piston shaft 11b or piston shaft 12b) in the reciprocating direction. Specifically, the servo coil 26 drives the torque motor according to an opening command current (driving opening signal) output from the servo module 22, which will be described later. The hydraulic pressure of the hydraulic drive device 27 is adjusted by a torque motor, and the piston shafts 11b and 12b move in the reciprocating direction. That is, the stop valve 11 and the control valve 12 are controlled via the stop valve driver 11a and the control valve driver 12a so as to have the same degree of opening as the opening degree signal output from the corresponding servo module 22. there is

In this embodiment, as will be described later, since the servo module 22 is tripled, each valve driver (the stop valve driver 11a and the control valve driver 12a) has three servo coils 26 and one hydraulic drive. It has a device 27 (Fig. 3). Each servo coil 26 receives an opening command current set value from each of the triple servo modules, and the magnetic field generated by the current flowing through each servo coil 26 drives the hydraulic drive device 27 .

The multiplexed servo control system 8 controls the opening degrees of the servo valves (stop valve 11 and control valve 12) by multiplexed servo modules 22 . The multiplexed servo control system 8 also detects an abnormality in the servo module 22 and performs recovery control of the servo module 22 in which an abnormality has been detected. In this embodiment, the multiplexed servo control system 8 is tripled (tripled servo module), but the multiplexing number can be changed as appropriate. Further, in this embodiment, the multiplexed servo control system 8 provided for the control valve 12 will be described, but the multiplexed servo control system 8 provided for the stop valve 11 has the same configuration.

FIG. 3 is a functional block diagram showing functions of the multiplexed servo control system 8. As shown in FIG. As shown in FIG. 3 , the multiplexed servo control system 8 includes a command section 21 , a servo section 20 , an abnormality determination section 28 and a return control section 29 .

In the multiplexed servo control system 8, the command unit 21, the abnormality determination unit 28, and the return control unit 29 are, for example, a CPU (Central Processing Unit) (not shown), a memory such as a RAM (Random Access Memory), and the like. It consists of a computer-readable recording medium and the like. A series of processes for realizing various functions described later is recorded in the form of a program on a recording medium, etc., and the CPU reads this program into RAM, etc., and executes processing and arithmetic processing of information. Various functions, which will be described later, are realized. The program may be pre-installed in a ROM or other storage medium, provided in a state stored in a computer-readable storage medium, or delivered via wired or wireless communication means. etc. may be applied. Computer-readable storage media include magnetic disks, magneto-optical disks, CD-ROMs, DVD-ROMs, semiconductor memories, and the like. Note that the command unit 21, the abnormality determination unit 28, and the return control unit 29 may be configured independently, or may be integrated.

The command unit 21 outputs an opening degree command (opening degree command value) for the control valve 12 (because the same applies to the stop valve 11, the description of the stop valve 11 will be omitted hereinafter). Specifically, the command unit 21 generates an opening degree command for the control valve 12 according to the operating state of the power generation system 1 such as the output required for the generator 4 and outputs the command to the servo unit 20 . In addition, it is preferable that a plurality of command units 21 are provided and multiplexed in order to improve reliability. It is preferable that the multiplexing number of the command section 21 is simplified to be equal to or less than the multiplexing number of the servo module 22 which is the output destination of the command section 21 . In this embodiment, since the servo modules 22 are tripled, the instruction units 21 are made two, that is, doubled. The same opening command is output from each of the duplicated command units 21 and input to each servo module 22 . Since each command unit 21 is multiplexed, they are synchronized (tracked) so as to output the same opening command. Here, "identical" means that the opening degree matches within a predetermined range (for example, ±0.5%, more preferably ±0.1%). Note that the command unit 21 may not be included in the multiplexed servo control system 8, and the opening command may be input to the servo unit 20 from the host controller of the power generation system 1. FIG.

The servo unit 20 has a plurality of servo modules 22 that output driving opening signals for driving the control valve 12 based on the opening command from the command unit 21 to the control valve 12 . In this embodiment, the servo section 20 is assumed to have three servo modules 22a to 22c (triple servo modules). In the following description, the servo modules 22a, 22b, and 22c are used to distinguish between the servo modules 22, and the servo modules 22a, 22b, and 22c are used to distinguish between the servo modules 22. , and will be described with reference numerals.

Each servo module 22 has a measuring section 23 and a driving section 24 for outputting a drive opening signal for driving the control valve 12 . Note that the multiplexed servo modules 22 do not have to have means for confirming synchronization with each other (means for synchronizing). That is, each servo module 22 operates independently based on the opening command output from the command unit 21 to output a driving opening signal (opening command current set value). Since synchronization of the opening signal (opening command current set value) is not checked, control logic or the like for synchronizing each servo module 22 can be eliminated.

The measurement unit 23 measures the degree of opening of the control valve 12 (for example, the amount of movement of the piston shaft in the hydraulic drive device 27 that drives the control valve 12) and outputs it as an opening measurement value. The measuring unit 23 is, for example, a differential transformer type displacement meter (LVDT), and is installed with respect to the control valve driver 12a (hydraulic drive device 27) in order to measure the opening degree of the control valve 12. ing. Specifically, as shown in FIG. 2, the measurement unit 23 is provided so as to be able to measure the displacement of the piston shaft 12b in the control valve driver 12a. FIG. 4 schematically shows the internal structure of the measuring section 23 (differential transformer type displacement gauge). As shown in FIGS. 2 and 4, the piston shaft 12b of the control valve driver 12a and the movable shaft 41 of the measuring section 23 are connected via a link mechanism 12d. In this embodiment, since the servo module 22 is configured to be tripled, three servo coils (A, B, C) are provided for one control valve driver 12a (piston shaft 12b). , three measuring units 23 may be connected. In the stop valve 11, similarly, the piston shaft 11b of the stop valve driver 11a and the movable shaft 41 of the measuring section 23 are connected via a link mechanism 11d.

The measurement unit 23 is a differential transformer displacement meter (LVDT) including a primary coil 42 (primary winding), a secondary coil 43 (secondary winding), a movable shaft 41, and a movable iron core 44. The case of FIG. 5 is a diagram showing an electrical equivalent circuit of the measuring section 23. As shown in FIG. A voltage is supplied to the primary coil 42 from a power supply 46 . For example, power supply 46 supplies primary coil 42 with an alternating voltage of 6V to 10V (eg, 1 kHz). As shown in FIGS. 4 and 5 , inside the measuring unit 23 , two secondary coils 43 a and 43 b are arranged side by side in the reciprocating direction of the movable iron core 44 . Further, one side of each of the secondary coils 43a and 43b is connected as a common line L1 in order to commonize the reference value of the measured potential. Each of the secondary coils 43 a and 43 b is electromagnetically coupled to the primary coil 42 via the movable iron core 44 . The movable iron core 44 is connected to the piston shaft 12b of the control valve driver 12a, and moves (displaces) as the piston shaft reciprocates. Voltages are induced in the secondary coils 43a and 43b according to the position of the movable iron core 44, and the induced voltages are measured by voltmeters 45a and 45b. It is assumed that the voltmeters 45a and 45b include rectifiers and measure rectified voltages.

That is, since the measurement unit 23 can detect the position of the moving core 44 in the reciprocating direction as the voltage of the secondary coils 43a and 43b, the reciprocating motion of the moving core 44 can be detected by referring to the measurement results of the voltmeters 45a and 45b. The position in the direction, ie the amount of movement of the piston axis, can be specified. Since the amount of movement of the piston shaft has a correlation with the degree of opening of the control valve 12, it is possible to accurately estimate the degree of opening of the control valve 12 from the measurement results of the voltmeters 45a and 45b. The voltage value information measured by the voltmeters 45a and 45b is output to the drive unit 24 as information indicating the opening state of the control valve 12 (opening measurement value).

The driving unit 24 outputs a drive opening signal (opening command current set value) for driving the control valve 12 based on the opening command from the command unit 21 and the opening of the control valve 12 measured by the measurement unit 23. Output. Specifically, the driving unit 24 receives the opening command output from the command unit 21 and the opening measurement value measured by the measuring unit 23 . Then, in the drive unit 24, a driving opening signal (opening command current) for the servo coil 26 is generated so that the target value of the opening (opening command) and the actual opening (opening measurement value) substantially match. set value) and output to the servo coil 26.

The internal configuration of the driving unit 24 is configured by, for example, a comparator, a computing unit, and the like. First, the opening command from the command unit 21 is input to the drive unit 24 and becomes the opening command in the servo module 22. is input to the comparator, and the comparator calculates an opening command to be corrected for performing feedback control. Then, the comparison result in the comparator is input to the computing unit, where it is converted into the opening command current set value, and the current (opening command current ) and output. An upper limit value (eg, +20 mA) and a lower limit value (eg, -20 mA) of the opening command current may be set to add a limiter function.

The abnormality determination unit 28 determines whether or not each servo module 22 has an abnormality (abnormality determination). Further, the abnormality determination unit 28 performs control to stop driving the control valve 12 for the servo module 22 determined to be abnormal. For this reason, the abnormality determination section 28 has an abnormality detection section 31 , a determination section 32 , and a suspension section 33 .

The abnormality detection section 31 detects abnormality of each measurement section 23 . Specifically, the abnormality detection unit 31 detects voltage values (voltages induced in the secondary coils 43a and 43b) output from the measurement units 23 installed to measure the opening of the control valve 12. , an abnormality of each measuring unit 23 is detected. For example, when a disconnection occurs in the measurement unit 23, the output voltage from the secondary winding in which the disconnection occurs becomes zero. Therefore, the abnormality detection unit 31 determines whether or not each measurement unit 23 is abnormal by comparing the voltage value output from the measurement unit 23 with a predetermined lower limit threshold. Furthermore, when an overvoltage is applied to the self-excited voltage of the primary coil 42, the presence or absence of an abnormality in each measuring unit 23 is checked by comparing the voltage value output from the measuring unit 23 with a predetermined upper limit threshold. Judging.

Further, when the secondary coils 43a and 43b are connected to each other by a common line L1 as shown in FIG. ), the voltage may flow from the other normal (non-broken) secondary coil 43b, and a residual voltage (higher than 0 V) may be generated in the secondary coil 43a where the wire breakage has occurred. There is a possibility that the residual voltage will exceed the lower limit threshold value, and disconnection may not be detected only with the lower limit threshold value. Therefore, focusing on the fact that the output voltage abruptly drops when a disconnection occurs in the secondary coil 43, the abnormality detection unit 31 detects the rate of change of the output voltage of the secondary coil 43 and a preset threshold value. A disconnection is also detected by comparison. That is, the abnormality detection unit 31 compares the voltage value output from the measurement unit 23 (the voltage induced in each of the secondary coils 43a and 43b) with the lower limit threshold, and the voltage output from the measurement unit 23. Abnormality of the measuring unit 23 is detected by two processes of comparing the change rate of the value and the preset threshold value. An abnormality determination result (a signal indicating whether or not there is an abnormality) in the abnormality determination unit 28 is output to the determination unit 32 .

The determination unit 32 determines whether or not there is an abnormality in each servo module 22 based on the deviation between the measurement results of the opening degrees of each valve in each measurement unit 23 and the detection result of the abnormality detection unit 31 . Specifically, the determination unit 32 determines that the deviation between the opening degree of the arbitrarily selected servo module 22, which is the measurement result of the measurement unit 23, and the opening degree of the measurement result of the measurement unit 23 of the other servo module 22 is a predetermined value. When at least one of the above conditions and the case where the abnormality of the measurement unit 23 in the arbitrarily selected servo module 22 is detected by the abnormality detection unit 31 is satisfied, an abnormality occurs in the arbitrarily selected servo module 22. It is determined that

FIG. 6 is a conceptual diagram showing abnormality determination processing in the determination unit 32. As shown in FIG. FIG. 6 shows an example of abnormality determination processing for the servo module 22a, and similar processing is performed for the other servo modules 22b and 22c. The determination unit 32 receives the opening degrees as the measurement results from the measurement units 23 . The measurement result of the measurement unit 23 in the servo module 22a is defined as an opening measurement value A, the measurement result of the measurement unit 23 in the servo module 22b is defined as an opening measurement value B, and the measurement result of the measurement unit 23 in the servo module 22c is defined as an opening measurement value A. Let C be the degree measurement value.

In the determination unit 32, first, the deviation (|AB|) between the opening measurement value A and the opening measurement value B, the deviation (|BC|) between the opening measurement value B and the opening measurement value C, and , and the deviation (|A−C|) of the opening measurement value A and the opening measurement value C are input to an AND circuit (AND circuit) to perform a logical operation. The input to the AND circuit is true (High, 1) when the deviation is greater than or equal to the predetermined threshold α, and the input to the AND circuit is false (Low, 0) when the deviation is less than the predetermined threshold α. It is assumed that Further, the deviation between the opening measurement value B and the opening measurement value C is input to the AND circuit via a logical NOT circuit (NOT circuit). That is, in the AND circuit in FIG. If it is less than the threshold value α and the deviation between the opening measurement value A and the opening measurement value C is equal to or greater than the predetermined threshold value α, it outputs true (High, 1), and if the input is another combination, it outputs false. (Low, 0) is output. That is, in the AND circuit in FIG. 6, the opening measurement value A of the servo module 22a deviates from the opening measurement values B and C of the other servo modules 22b and 22c by a predetermined threshold value α or more, and If the opening measurement values B and C of the servo modules 22b and 22c do not deviate from each other by a predetermined threshold α or more, there is a possibility that only the opening measurement value A is abnormal and that the servo module 22a is abnormal. detect that there is In other words, in the AND circuit in the determination unit 32, when only one opening measurement value deviates from the other opening measurement values (AND All inputs to the circuit are true) to detect that this particular opening measurement may be incorrect. In the abnormality determination process for the servo module 22a, the difference between the opening measurement value B and the opening measurement value C is passed through a logical NOT circuit (NOT circuit). The deviation between the degree of opening measurement value A and the degree of opening measurement value C passes through a logical NOT circuit (NOT circuit), and in the case of abnormality determination processing for the servo module 22c, the deviation between the degree of opening measurement value A and the degree of opening measurement value B Via a not circuit (NOT circuit).

Then, the output result of the AND circuit and the abnormality detection result of the measurement unit 23 by the abnormality detection unit 31 are input to a logical sum circuit (OR circuit). The abnormality detection unit 31 outputs true (High, 1) when an abnormality of the abnormality detection unit 31 is detected, and outputs false (Low, 0) when an abnormality of the abnormality detection unit 31 is not detected. It is assumed that Since FIG. 6 shows an example of abnormality determination processing for the servo module 22a, the abnormality detection result input to the AND circuit is the abnormality detection result for the measurement unit 23 in the servo module 22a. That is, as shown in FIG. 6, when an abnormality is detected in the opening measurement value A, which is the measurement result of the measurement unit 23 in the servo module 22a, the abnormality detection unit 31 outputs true (High, 1), If no abnormality is detected in the opening measurement value A, the abnormality detection unit 31 outputs false (Low, 0).

The OR circuit outputs true (High, 1) when at least one of the output result of the AND circuit and the abnormality detection result of the measurement unit 23 by the abnormality detection unit 31 is true (High, 1). That is, in the OR circuit, even though the opening measurement values B and C do not deviate from each other, only the opening measurement value A deviates from the other opening measurement values B and C (from the AND circuit and/or when an abnormality is detected in the measurement unit 23 of the servo module 22a (when the abnormality detection unit 31 outputs true), an abnormality has occurred in the servo module 22a. I judge.

On the other hand, in the AND circuit in the determination unit 32, when two opening measurement values are diverging from each other, it cannot be detected unless only one other opening measurement value is not diverging. For example, the deviation between the opening measurement value A and the opening measurement value B is a predetermined threshold value α or more, the deviation between the opening measurement value B and the opening measurement value C is a predetermined threshold value α or more, and the opening measurement value If the deviation between A and the opening measurement value C is less than a predetermined threshold α, false (low, 0) is output, but the opening measurement value A in the servo module 22a and the opening measurement value B in the servo module 22b are output. However, it deviates from the opening measurement value C of the other servo module 22c by a predetermined threshold α or more, the opening measurement value A and the opening measurement value B are not normal, and the servo module 22a and the servo module 22b An abnormality has occurred and the servo module 22c is in a situation where it cannot be detected as normal. At this time, it can be judged that an abnormality occurs in the servo modules 22a and 22b and the servo module 22c is normal based on information indicating an abnormality in the opening measurement value from the abnormality detection unit 31. FIG.

6 is provided for each servo module 22 in this way, which servo module 22 has an abnormality. It is possible to identify whether an abnormality has occurred in The determination result of the determining section 32 is output to the canceling section 33 .

The suspending unit 33 suspends the output of the drive opening signal (opening command current set value) for driving the control valve 12 by the servo module 22 determined to be abnormal by the determining unit 32 (suspension control). Specifically, the suspending unit 33 cuts off the conduction of the opening command current set value output by the servo module 22 determined to be abnormal by the determining unit 32 . In other words, the opening command current (driving opening signal) of the servo module 22 determined to be abnormal is prevented from being input to the servo coil 26 . Therefore, the servo coil 26 is driven only by the opening command current from the servo module 22 which is assumed to be normal. The method of interrupting the output of the servo module 22 by the stop unit 33 is, for example, to provide a switching element or the like in the path through which the opening command current set value, which is the output of the servo coil 26, is conducted, and to control the opening and closing of the switching element. It is possible to adopt various methods such as

The return control unit 29 controls the return (release of stop control) of the servo module 22 determined to be abnormal. Specifically, the return control unit 29 determines whether the opening command value in the servo module 22 of the servo module 22 determined to be abnormal by the determination unit 32 and the opening command value from the command unit 21 are the same. , the suspension control in the suspension unit 33 is canceled. When the servo module 22 is determined to be abnormal and the stop control is performed, the control valve 12 is controlled by another servo module 22, but the number of multiplexing is reduced, resulting in a decrease in reliability. For this reason, the servo module 22 determined to be abnormal needs to be reset or replaced, and then restored.

FIG. 7 shows an example of each command value of the servo module 22 when an abnormality occurs. In FIG. 7, the command unit 21 outputs an opening command value of 80% when the opening of the control valve 12 is set from 0% (fully closed) to 100% (fully open). showing. As shown in FIG. 7, when the servo module 22 is operating normally (period T1), the opening command from the command unit 21 and the opening command value in the servo module 22 match. In the driving unit 24, an opening command current set value is calculated based on the opening command value in the servo module 22 and the opening of the control valve 12 measured by the measuring unit 23, and the servo is operated based on the opening command current set value. An opening command current is output from the module 22 to the servo coil 26 . The opening command current setting value in FIG. Control is performed during settling to maintain an opening of 12, and a minute current (substantially zero) is output from the servo module 22 to the servo coil 26 as an opening command current. However, when it is determined that the servo module 22 is abnormal, stop control is executed, and work such as resetting the servo module 22 and parts replacement is performed. In the servo module 22 immediately after reset work or parts replacement, the opening command value in the servo module 22 is in the initial state, and the initial value (for example, 0%) is output. For this reason, if the servo module 22 that has been determined to be abnormal is subjected to reset work, part replacement, or the like, and an attempt is made to restore it immediately, the opening command value from the command unit 21 will not The opening command value is the initial value, the opening command current set value in the servo module 22 is calculated based on the initial value of the opening command value, and the servo coil 26 is transferred from the servo module 22 according to the opening command current set value. The opening degree command current is output to , and there is a possibility that the control of the control valve 12 is destabilized. Therefore, the return control unit 29 performs return control so that the servo module 22 determined to be abnormal can return without destabilizing the control of the control valve 12 .

Specifically, when the restoration control unit 29 restores (cancels the stop control) the servo module 22 determined to be abnormal, the opening command value in the servo module 22 and the opening command value in the command unit 21 are equal to each other. A determination is made as to whether or not a state indicating the same degree of opening has occurred, and if they have reached a state indicating the same value, the stop control of the servo module 22 is cancelled, and the servo module 22 is returned. In this case, with the output of the servo module 22 to be restored open, by inputting an opening degree command in the servo module 22 and causing the measurement unit 23 to perform measurement, the output of the servo module 22 is returned to the normal state. can do. That is, the return control unit 29 waits until the opening command value in the servo module 22 and the opening command value of the command unit 21 become the same as in the period T2 shown in FIG. 7, and then cancels the stop control. . Here, "same" means that the opening degree matches within a predetermined range (for example, ±2%). The predetermined range is the same predetermined range with the same accuracy as when the same opening command is output from each of the duplicated command units 21 and synchronized (tracked) to output the same opening command. is set, but any accuracy range may be set strictly according to the operation. In FIG. 7, the opening command value in the servo module 22 becomes the same as the opening command value of the command unit 21 over a period of time T2 after resetting. is caused when the opening command value in the servo module 22 cannot follow the opening command value of the command unit 21, or when the servo module 22 is intentionally delayed for a period of time T2 for safety reasons. This is caused by various factors, such as when the internal opening command value is raised. The return control unit 29 waits until the opening command value in the servo module 22 and the opening command value in the command unit 21 become the same before canceling the stop control. It is possible to stably restore the servo module 22 in response to the delay in rising of the command value.

When the return control unit 29 returns the servo module 22, if the time at which the opening command value in the servo module 22 and the opening command value from the command unit 21 are the same can be specified in advance. Alternatively, the output of the servo module 22 may simply be cut off for that amount of time (standby control).

Next, abnormality determination processing and recovery processing by the multiplexed servo control system 8 will be described with reference to FIG. The flow shown in FIG. 8 is repeatedly executed at a predetermined control cycle while the power generation system 1 is operating (especially when the control valve 12 is operating).

First, it is determined whether or not an abnormality has occurred in each servo module 22 (S101). Specifically, an abnormality detection process as shown in FIG. 6 is executed corresponding to each servo module 22, and an abnormality determination for each servo module 22 is performed.

If it is determined that no abnormality has occurred in each servo module 22 (NO determination in S101), the abnormality determination process is terminated.

If it is determined that an abnormality has occurred in the servo module 22 (YES determination in S101), the drive opening signal output from the servo module 22 determined to be abnormal is cut off (S102). . The servo modules 22 (normal servo modules 22) other than the servo module 22 determined to be abnormal continue to operate.

Next, the servo module 22 determined to be abnormal is reset or replaced (S103). Note that restoration work such as reset processing and replacement of the servo module 22 may be performed manually by an operator of the power generation system 1 or the like, or a spare servo module 22 or the like may be prepared in advance. , the servo module 22 determined to be abnormal may be automatically replaced.

Next, in the servo module 22 to be restored, it is determined whether or not the opening command value in the servo module 22 in which the restoration work has been performed and the opening command value of the command section 21 indicate the same opening. (S104).

If it is determined that the opening command value in the servo module 22 and the opening command value from the command unit 21 do not indicate the same opening (NO determination in S104), S104 is executed again. be done. If a period in which the opening command value in the servo module 22 and the opening command value from the command unit 21 do not indicate the same opening continues for a predetermined time or longer, for example, the operator of the power generation system 1 It is also possible to notify to and be careful to check whether other abnormalities have occurred.

If it is determined that the opening command value in the servo module 22 and the opening command value in the command unit 21 are the same (YES in S104), the servo module 22 is stopped. is released and restored (S105).

As described above, according to the multiplexed servo control system, the multiplexed servo control method, and the power generation system according to the present embodiment, the measurement unit 23 that measures the opening degree of the servo valves (the stop valve 11 and the control valve 12) , and the abnormality detection result of the measurement unit 23 itself, the abnormality determination of the multiplexed servo module 22 is performed. can be specified more accurately. For example, if the number of installed servo modules 22 is 3 (triple servo modules), if an abnormality occurs in one of them, the measurement result of each opening degree of the measurement unit 23 of each servo module 22 It is possible to identify which servo module 22 has an abnormality based on the deviation of . However, when an abnormality occurs in two of the tripled servo modules 22, the servo module 22 in which the abnormality has occurred cannot be specified only by the deviation of the measurement result of the measuring unit 23 of each servo module 22. . Therefore, by focusing on the measurement unit 23 in the servo module 22, where an abnormality is likely to occur, and considering the detection result of the abnormality of the measurement unit 23 itself, it is possible to prevent the occurrence of an abnormality in two of the triplets. Even so, it is possible to identify the servo module 22 in which the abnormality has occurred, cut off the output from the servo module 22 in which the abnormality has occurred, and stop the operation. Therefore, the accuracy of abnormality determination of the multiplexed servo modules 22 can be improved, and the opening command current (output signal) of the servo module 22 determined to be abnormal is the servo valve (stop valve 11 and control valve 12). is not input to the servo coil 26, it is possible to suppress unstable operation. In addition, since the servo module 22 determined to be abnormal can be specified, work such as reset processing or replacement of the servo module 22 determined to be abnormal can be performed quickly.

In addition, since the command to drive the servo valves (the stop valve 11 and the control valve 12) by the servo module 22 determined to be abnormal is stopped, the servo valves (the stop valve 11 and the control valve 12) are controlled by the normal servo module 22. can be driven by stably outputting commands to That is, the servo valves (the stop valve 11 and the control valve 12) can be continuously operated stably. In addition, while the servo valves (the stop valve 11 and the control valve 12) are continuously operated without stopping the power generation system 1, the servo module 22 determined to be abnormal is reset or replaced. and can be restored.

Further, when the servo module 22 determined to be abnormal is to be restored (cancel the stop control), the opening command value in the servo module 22 determined to be abnormal is the same as the opening command value from the command unit 21. Since the condition is that the signal indicates the degree of opening, the servo module 22 can be returned stably. For example, when it is determined that the servo module 22 is abnormal and the stop control is executed, the servo module 22 determined to be abnormal may be subjected to reset processing, part replacement processing, or the like. In such a case, the opening command value in the servo module 22 determined to be abnormal may be the initial value (for example, 0). 11 and control valve 12) may become unstable and cause failure. Therefore, the servo module 22 determined to be abnormal is not restored until the opening command value in the servo module 22 matches the opening command value of the command unit 21 and returns to a normal state. Therefore, it is possible to prevent the control of the servo valves (the stop valve 11 and the control valve 12) from becoming unstable.

In addition, since a plurality of command units 21 that output opening commands for the servo valves (stop valve 11 and control valve 12) are installed and synchronized with each other, the opening command output from each command unit 21 is a different signal. , and the reliability of the command unit 21 can be improved.

In addition, since means for confirming synchronization between the servo modules 22 is not provided, control logic or the like for synchronizing the servo modules 22 can be made unnecessary, thereby simplifying the system and reducing costs. becomes possible.

The present invention is not limited to the above-described embodiments, and various modifications can be made without departing from the gist of the invention.

For example, in the present embodiment, the multiplexed servo control system 8 includes both the abnormality determination section 28 and the return control section 29, but may include only the abnormality determination section 28. FIG.

1: Power generation system 2: Boiler 3: Turbine (steam turbine)
4: Generator 5: Condenser 6: Feedwater pump 7: Turbine steam control valve 8: Multiplexed servo control system 11: Stop valve (servo valve)
11a: stop valve driver 11b: piston shaft 11c: link mechanism 11d: link mechanism 12: control valve (servo valve)
12a: control valve driver 12b: piston shaft 12c: link mechanism 12d: link mechanism 20: servo unit 21: command unit 22 (22a to 22c): servo module 23: measurement unit 24: drive unit 26: servo coil 27: hydraulic pressure Drive device 28 : Abnormality determination unit 29 : Return control unit 31 : Abnormality detection unit 32 : Determination unit 33 : Cancellation unit 41 : Movable shaft 42 : Primary coil 43 : Secondary coils 43a and 43b : Secondary coil 44 : Movable iron core 45a, 45b: voltmeter 46: power supply

Claims (10)

a servo unit having a plurality of servo modules that output driving opening signals to the servo valves based on opening commands for predetermined servo valves;
an abnormality determination unit that determines an abnormality of each servo module;
a return control unit;
with
Each said servo module includes:
a measurement unit that measures the degree of opening of the servo valve;
a driving unit that outputs the driving opening signal to the servo valve based on the opening command and the opening measured by the measuring unit;
has
The abnormality determination unit is
an abnormality detection unit that detects an abnormality in each of the measurement units;
a determination unit that determines the presence or absence of an abnormality in each of the servo modules based on the deviation between the measurement results of the opening measured by each of the measurement units and the detection result of the abnormality detection unit;
a suspension unit that suspends output of the drive opening signal to the servo valve by the servo module that is determined to be abnormal by the determination unit;
has
The return control unit is configured to provide an opening command used for outputting the drive opening signal in the servo module determined to be abnormal when the servo module determined to be abnormal by the determination unit is restored. A multiplexed servo control system that cancels stop control in the stop unit and returns when the value and the opening command input to the servo module are the same . The judging unit determines if the difference between the measurement result of the measuring unit in the arbitrarily selected servo module and the measurement result of the measuring unit in the other servo module is equal to or greater than a predetermined value, and if the abnormality detection unit detects the 2. When at least one condition of detecting an abnormality in said measurement unit in said arbitrarily selected servo module is satisfied, it is determined that said arbitrarily selected servo module has an abnormality. A multiplexed servo control system as described in . The servo module is
outputting the drive opening signal based on the opening command value in the servo module corresponding to the input opening command and the opening measured by the measuring unit;
2. A multiplex system according to claim 1, wherein said opening command value in said servo module does not follow said input opening command and is not in the same state before recovery from an abnormality. customized servo control system. a servo unit having a plurality of servo modules that output driving opening signals to the servo valves based on opening commands for predetermined servo valves;
an abnormality determination unit that determines an abnormality of each of the servo modules and stops outputting an opening signal for driving the servo valve by the servo module determined to be abnormal;
an opening command value used for outputting the drive opening signal in the servo module determined to be abnormal when the servo module determined to be abnormal by the abnormality determination unit is restored; a return control unit for canceling stop control of the servo module determined to be abnormal by the abnormality determination unit and restoring the servo module when the opening command input to the module is the same;
A multiplexed servo control system comprising: Each said servo module includes:
a measurement unit that measures the degree of opening of the servo valve;
a driving unit that outputs a drive opening signal to the servo valve based on the opening command and the opening measured by the measuring unit;
has
The abnormality determination unit is
an abnormality detection unit that detects an abnormality in each of the measurement units;
a determination unit that determines whether there is an abnormality in each of the servo modules based on the deviation between the measurement results measured by each of the measurement units and the detection result of the abnormality detection unit;
5. The multiplexed servo control system of claim 4 , comprising: A plurality of command units that output the opening command for the servo valve,
6. A multiplexed servo control system according to any one of claims 1 to 5 , wherein said command units are synchronized with each other so as to output the same opening command. 7. A multiplexed servo control system as claimed in any one of claims 1 to 6 , wherein each said servo module is provided with no means for ascertaining synchronization with each other. a measuring unit for measuring the opening of a predetermined servo valve; and a driving unit for outputting a driving opening signal to the servo valve based on an opening command for the servo valve and the opening measured by the measuring unit. A multiplexed servo control method for a plurality of servo modules comprising:
an abnormality detection step of detecting an abnormality in each of the measuring units;
a determination step of determining whether or not there is an abnormality in each of the servo modules based on the deviation between the measurement results measured by each of the measurement units and the detection result of the abnormality detection step;
a stopping step of stopping the output of the driving opening signal to the servo valve by the servo module determined to be abnormal in the determining step;
an opening command value used for outputting the drive opening signal in the servo module determined to be abnormal when the servo module determined to be abnormal in the determination step is restored; a return control step of canceling the stop control in the stop step and performing a return when the opening degree command input to is the same as the opening command;
A multiplexed servo control method comprising: A multiplexed servo control method for a plurality of servo modules for outputting a drive opening signal to a servo valve based on an opening command for a predetermined servo valve, comprising:
an abnormality determination step of performing an abnormality determination for each of the servo modules, and stopping output of an opening signal for driving the servo valve by the servo module determined to be abnormal;
an opening command value used for outputting the drive opening signal in the servo module determined to be abnormal when the servo module determined to be abnormal by the abnormality determination step is restored; a return control step of canceling stop control of the servo module determined to be abnormal by the abnormality determination step and restoring the servo module when the opening command input to the module is the same;
A multiplexed servo control method comprising: A power generation system comprising a multiplexed servo control system according to any one of claims 1 to 7 .

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