JP2011027090A - Method for monitoring opening of steam control valve - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a method for monitoring the opening of a steam control valve, with which an operator can quickly correspond to abnormal conditions in the operation for opening a steam control valve. <P>SOLUTION: This is a method of monitoring the opening of a steam control valve 32 for increasing/decreasing the quantity of steam to be supplied to a turbine 20 for driving a water supply pump 16 in a power generation plant S. An alarm device 70A is operated when a first deviation between the opening of the steam control valve 32 and a target opening thereof becomes a first set value or more. <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

  The present invention relates to a method for monitoring the opening of a steam control valve.

  Conventionally, in thermal power and nuclear power plants, power generation turbines are rotated by steam generated by a steam generator to generate power. A turbine drive pump is used to supply water to the steam generator. The turbine drive pump is driven by supplying a part of the steam generated by the steam generator, and the amount of water supplied to the steam generator increases or decreases in proportion to the amount of steam supplied. The amount of steam supplied to the turbine-driven pump is increased or decreased depending on the opening of a steam control valve attached to the pump. By adjusting the opening of the steam control valve, the amount of water supplied to the steam generator is increased or decreased, and the water level of the steam generator is made constant. As an opening adjusting device for such a steam control valve, devices described in Patent Documents 1 and 2 below have been proposed. The devices described in Patent Documents 1 and 2 are configured by combining a plurality of hydraulic devices and a link mechanism. The hydraulic device and the link mechanism are operated by the electric signal, and the steam control valve connected to the link mechanism is operated.

JP 2002-147204 A JP-A-62-2213603

  In the devices of Patent Documents 1 and 2, when an abnormality occurs in the opening / closing operation of the steam control valve, it is necessary for the operator of the power plant to quickly cope with the operation abnormality.

  The present invention has been completed based on the above circumstances, and when an abnormality occurs in the opening / closing operation of the steam control valve, the opening degree monitoring method that allows the operator to quickly cope with the abnormality The purpose is to provide.

  The present invention relates to an opening monitoring method for a steam control valve for increasing or decreasing the amount of steam supplied to a turbine for driving a feed water pump in a power plant, wherein the first deviation between the opening of the steam control valve and a target opening is provided. Is characterized in that the first alarm device is activated on the condition that the value becomes equal to or greater than the first set value.

As an embodiment of the present invention, the following configuration is preferable.
An opening / closing mechanism that opens and closes the steam control valve includes: a first valve that opens and closes by an electrical signal; a first hydraulic actuator that operates by hydraulic fluid supplied by opening the first valve; and An electrohydraulic control type composed of a second valve that is opened and closed by an operation, and a second hydraulic actuator that is operated by hydraulic oil supplied by opening the second valve and opens and closes the steam control valve The second alarm device is actuated on the condition that the second deviation between the displacement of the first hydraulic actuator and the target displacement is equal to or greater than a second set value. With such a configuration, when the second alarm device is activated, it can be estimated that an abnormality has occurred in the first hydraulic actuator. For this reason, the operator can easily identify the abnormal part and can respond more quickly.

  The first alarm is activated on the condition that the first deviation continues for a preset first predetermined time and becomes equal to or greater than the first set value, and the second deviation is preset. The second alarm device is operated on condition that the second set value or more is continued for a second predetermined time. If it does in this way, each 1st deviation and 2nd deviation will continue for each predetermined time, and when each becomes more than each setting value, each corresponding alarm device will operate. For this reason, for example, when the first and second deviations increase instantaneously due to a delay in power transmission of both hydraulic actuators that occurs when the output of the power plant increases, it is possible to prevent each alarm device from operating.

  According to the present invention, it can be confirmed that an abnormality has occurred in the operation of the steam control valve by the operation of the first alarm device. Thus, the operator can quickly respond to the abnormal operation.

System diagram of nuclear power plant Diagram showing the open / close mechanism of the steam control valve Diagram showing operation of link mechanism when speed relay is fixed

<Embodiment>
An embodiment of the present invention will be described with reference to FIGS.
(1) Overall Configuration FIG. 1 is a system diagram of a nuclear power plant. A nuclear power plant S (hereinafter, power plant S) according to the present embodiment is configured by sequentially connecting a reactor 11, a power generation turbine 12, a condenser 13, and feed water pumps 16 and 17 through piping.

  The nuclear reactor 11 includes a fuel assembly 11A and a control rod 11B in a nuclear reactor pressure vessel 11C. The fuel assembly 11A is configured by arranging a plurality of fuel rods. A fuel containing a fissile material is sealed in the fuel rod, and the water in the nuclear reactor pressure vessel 11C is boiled by heat generated when the fuel is fissioned to generate steam (boiling water). Shaped light water reactor: BWR).

  The control rod 11B absorbs neutrons generated at the time of fission, and is accommodated so as to be freely inserted and removed between, for example, a set of four fuel assemblies 11A. Thereby, the control rod 11B is taken in and out of the fuel assembly 11A, thereby adjusting the number of neutrons in the reactor and adjusting the output of the reactor 11.

  A recirculation pump 14 is attached to the reactor pressure vessel 11C. The recirculation pump 14 circulates light water (coolant) in the reactor pressure vessel 11C, and thus has a function of adjusting the amount of steam bubbles generated in the light water by boiling. More specifically, when the amount of circulation by the recirculation pump 14 increases, the amount of steam bubbles decreases (the density of light water increases). Since the light water in the reactor pressure vessel 11C plays a role of a moderator, the amount of steam bubbles decreases, resulting in an increase in the number of neutrons to be decelerated and an increase in the output of the reactor 11. With the above configuration, the amount of steam output from the nuclear reactor 11 is controlled by the amount of control rods 11 </ b> B in and out and the amount of rotation of the recirculation pump 14. Further, the nuclear reactor 11 is provided with a water level meter 15 so that the water level of the light water in the nuclear reactor 11 can be measured.

  The power generation turbine 12 is rotationally driven by supplying steam generated in the nuclear reactor 11. The condenser 13 has a configuration in which cooling water circulates therein, and has a function of condensing steam exhausted from the power generation turbine 12 into condensate.

  The feed water pumps 16 and 17 have a function of increasing the pressure of the condensate condensed in the condenser 13 and supplying water to the reactor 11. The feed water pump is composed of two feed water pumps 16 and 17, and the drive of both systems is switched by the output of the reactor 11. Specifically, the motor-driven feed water pumps 17a and 17b are driven mainly when the power generation turbine 12 is started, and the turbine-driven feed water pumps 16a and 16b are driven mainly at the time of output increase and rated output (details). Will be described later). The water supply pump 17 is also driven as an alternative when the water supply pump 16 fails.

  With the above configuration, the nuclear power plant S constitutes a Rankine cycle, and circulates steam and condensate to continuously feed steam to the power generation turbine 12 to rotate and drive the generator G connected to the turbine shaft. Power generation.

  Turbine-driven feed pumps 16a and 16b are respectively provided with turbines 20a and 20b. The turbines 20a and 20b are driven by a part of the steam generated by the reactor 11 being sent, and have a function of rotating the feed water pumps 16a and 16b.

  A steam control valve 32 and an opening / closing mechanism 30 for the steam control valve 32 are installed on the steam inlet side of the turbines 20a and 20b. The opening / closing mechanism 30 is driven by a signal from the control device 37, and the opening of the steam control valve 32 is adjusted to increase or decrease the amount of steam to the turbines 20a and 20b.

(2) Configuration of Open / Close Mechanism of Steam Control Valve Next, the open / close mechanism 30 of the steam control valve 32 to which the opening degree monitoring method of the present invention is applied will be described in detail. As shown in FIG. 2, the opening / closing mechanism 30 mainly includes a servo valve 38 (first valve), a spool opening / closing device 36, a servo motor 48 (second hydraulic actuator), and a motor power transmission mechanism 49. The opening / closing mechanism 30 opens the servo valve 38 with an electric signal, thereby supplying hydraulic oil to the spool opening / closing device 36 and the servo motor 48 and opening / closing the steam control valve 32 with greater power by hydraulic pressure (electrohydraulic control). Formula).

  The servo valve 38 is provided between the oil supply source and the hydraulic cylinder 39, and is opened and closed by a control signal (electric signal) from the control device 37, so that the hydraulic oil is supplied to the port 39A or the port 39B of the hydraulic cylinder 39. Has the function of switching supply.

  The spool opening / closing device 36 includes a hydraulic cylinder 39 (first hydraulic actuator) driven by hydraulic pressure, a pilot valve 41, a speed relay 42, and links A1 to A6 (links extending in the left-right direction in FIG. 2) for transmitting the power of these devices. ) And links B <b> 1 to B <b> 4 (links extending in the vertical direction in FIG. 2), and has a function of opening and closing a spool valve 48 </ b> B (second valve) described later by the operation of the hydraulic cylinder 39.

  The pilot valve 41 is connected to an oil supply source, and the spool 41C moves so that the inflow of oil to the port 42A of the speed relay 42 or the outflow of hydraulic oil from the port 42A can be switched.

  In the speed relay 42, when the oil is supplied from the pilot valve 41, the piston 42D rises. The piston 42D is configured to be urged in a downward direction by a built-in spring 42E.

  One end of the link A1 is rotatably fixed by a hinge, and the other end is connected to the lower end of the link B1. Further, the link A1 is connected to the rod 39F of the hydraulic cylinder 39 at a substantially intermediate position in the length direction.

  One end of the link A2 is connected to the upper end of the link B1, and the other end is connected to the lower end of the link B2. The link A2 is connected to a rod 41F extending from the spool 41C of the pilot valve 41 at a location closer to the link B2 than the middle in the length direction. The link A3 is fixed so as to be rotatable at a substantially intermediate position in the length direction.

  One end of the link A3 is connected to the upper end of the link B2, and the other end is connected to the rod 42F of the speed relay 42. The link A4 is fixed so as to be rotatable at a substantially intermediate position in the length direction. One end of the link A4 is connected to the upper end of the rod 42F of the speed relay 42, and the other end is connected to the lower end of the link B3.

  The link A5 is fixed so as to be rotatable at a substantially intermediate position in the length direction. One end of the link A5 is connected to the upper end of the link B3, and the other end is connected to the upper end of the link B4. One end of the link A6 is connected to the lower end of the link B4, and the other end is connected to a rod 48F extending from the piston 48D of the servo motor 48.

  The link A6 is connected to the upper end of a rod 48G extending from the spool 48C of the servo motor 48 at a position closer to the link B4 than the middle in the length direction. In addition, the connection location of each link and each rod described above is rotatably connected by a hinge.

  The servo motor 48 is connected to an oil supply source, and when the spool 48C of the attached spool valve 48B moves (opens / closes the spool valve 48B), the hydraulic oil flows into the A chamber 48A and from the A chamber 48A. The hydraulic oil outflow can be switched. Further, the piston 48D attached to the A chamber 48A is urged in the upward direction by the spring 48E.

  The motor power transmission mechanism 49 includes arms C1 and C2 and a rod C3. One end of the arm C1 is rotatably connected to the upper end of the rod 48F of the servo motor 48, and the other end is attached to one end of the rod C3. The rod C3 has an elongated cylindrical shape, and is attached to the bracket 33 so as to be rotatable in the axial direction. The other end of the rod C3 is attached to one end of the arm C2. One end of the arm C2 is rotatably attached to the bracket 34. The other end of the arm C2 is connected to the steam control valve 32 via the relay member 50, and the steam control valve 32 is configured to move up and down (open and close) as the arm C2 rotates about one end.

  A differential transformer 55 is attached to the upper end of the rod 39F of the hydraulic cylinder 39. A differential transformer 56 is attached to the arm C1 via a relay member 57. Both differential transformers 55 and 56 are mainly composed of a movable core and a fixed primary coil and secondary coil (both not shown), and each core is a rod 39F of the hydraulic cylinder 39 and a relay. Each is attached to a member 57.

  Thus, when the position of the core is displaced while the primary coil is excited, an induced voltage corresponding to the position of the core is generated from the secondary coil. Therefore, the displacement of the hydraulic cylinder 39 can be detected by the differential transformer 55, and the displacement of the arm C1 can be detected by the differential transformer 56. The differential transformers 55 and 56 are each electrically connected to the control device 37, and a signal corresponding to each displacement is output to the control device 37. Note that the control device 37 compares signals output from the two differential transformers 55 </ b> A and 55 </ b> B of the hydraulic cylinder 39, and acquires a signal with a large output as the displacement of the hydraulic cylinder 39. Thereby, even if a malfunction occurs in one of the differential transformers 55A and 55B, the displacement of the hydraulic cylinder 39 can be reliably acquired.

  The control device 37 calculates the target opening degree of the steam control valve 32 from the target water supply amount of the water supply pump 16. Then, the target displacement of the hydraulic cylinder 39 is calculated from the target opening of the steam control valve 32. The control device 37 outputs a control signal to the servo valve 38 and adjusts the opening degree of the servo valve 38 so that the hydraulic cylinder 39 has a target displacement. The control signal output from the control device 37 to the servo valve 38 is fed back to the control device 37, and it is possible to monitor whether the control signal is output correctly.

  Now, two types of alarm devices 70A and 70B are electrically connected to the control device 37. Each of the alarm devices 70A and 70B includes, for example, a buzzer and a display lamp, and has a function of notifying the operator of the power plant S of the abnormality of the opening / closing mechanism 30. The control device 37 calculates a first deviation between the target opening degree of the steam control valve 32 and the displacement of the arm C1 output from the differential transformer 56 (corresponding to the opening degree of the steam control valve 32).

  The storage unit 37A in the control device 37 stores a first set value and a first predetermined time. Then, the control device 37 outputs a signal to the alarm device 70A on the condition that the state where the first deviation is equal to or greater than the first set value has continued for the first predetermined time, and operates the alarm device 70A. The first set value and the first predetermined time are determined based on the first deviation data acquired during normal operation of the power plant. In the present embodiment, for example, when the state in which the first deviation becomes ± 20% (first set value) or more continues for 2 seconds (first predetermined time) or more, the alarm device 70A (first alarm device). Is set to operate.

  The storage unit 37A stores a second set value and a second predetermined time. The control device 37 calculates a second deviation between the target displacement of the hydraulic cylinder 39 and the displacement of the hydraulic cylinder 39 output from the differential transformer 55. Then, the control device 37 outputs a signal to the alarm device 70B on the condition that the state where the second deviation is equal to or greater than the second set value has continued for the second predetermined time, and the alarm device 70B (second alarm device) is output. Operate.

  The second set value and the second predetermined time are determined based on the second deviation data acquired during the normal operation of the power plant, similarly to the first set value and the first predetermined time. In the present embodiment, for example, when the state where the second deviation is ± 15% (second set value) or more continues for 7 seconds (second predetermined time) or more, the alarm device 70B (second alarm device). Is set to operate.

  Further, the trip set value is stored in the storage unit 37A. The trip set value is set to a value higher than the first set value described above, and is set to ± 25%, for example, in the present embodiment. The control device 37 is electrically connected to the control device 80. The control device 37 compares the first deviation with the trip set value to determine whether the first deviation has reached the trip set value, and outputs the determination result to the control device 80.

  The control device 81 is electrically connected to the water level meter 15 and the control device 80 of the nuclear reactor 11. The storage unit 81A provided in the control device 81 stores a plurality of preset water level levels. The control device 81 determines whether or not the reactor water level output from the water level gauge 15 is within the set water level level, and outputs the determination result to the control device 80.

The control device 80 is electrically connected to the opening / closing mechanism 30 and each water supply pump 17 (17a, 17b). The control device 80 receives the outputs from the control devices 37 and 81, and when the following conditions (1) and (2) are simultaneously satisfied, the operation of the water supply pump 16 is stopped and the operation is switched to the operation of the water supply pump 17. It has a function.
Condition (1) The first deviation reaches the trip set value (becomes + 25% or −25%).
Condition (2) The reactor water level output from the water level gauge is outside the range of the set water level.
In order to stop the operation of the water supply pump 16 from the control device 80, the steam control valve 32 may be closed by sending a command from the control device 80 to the opening / closing mechanism 30. Moreover, it is good also as a structure which makes the control apparatus 37 close the steam control valve 32 by sending a command signal from the control apparatus 80 to the control apparatus 37.

(3) Power Plant Operation Method Next, the power plant S operation method will be described. In order to start up the nuclear reactor 11, the control rod 11B is pulled out of the fuel assembly 11A to start nuclear fission. As a result, steam generated when the light water in the reactor 11 boils is sent to the power generation turbine 12. At the same time, the electrically driven water supply pump 17a is driven to supply water to the nuclear reactor 11. Further, by pulling out the control rod 11B, the output of the nuclear reactor is increased, and when the output of the power generation turbine (proportional to the amount of steam from the nuclear reactor) exceeds 20% of the rated power generation, for example, the control device 80 The water supply pump 17a is stopped by the command from, and the turbine-driven water supply pump 16a is driven instead.

  Further, the amount of steam from the reactor 11 is increased by raising the output of the recirculation pump 14 at the same time that the control rod 11B is pulled out. In response to the increase in the amount of steam, the amount of water supplied to the reactor pressure vessel is increased by opening the steam control valve 32 of the water supply pump 16a. When the output exceeds 50%, the water supply pump 16b is driven in addition to the water supply pump 16a. Thereafter, the water supply amount of the water supply pumps 16a and 16b is increased by opening the opening of each steam control valve 32 of the water supply pumps 16a and 16b.

  The steam control valve 32 is opened as follows. First, a control signal is output from the control device 37 to the servo valve 38. As a result, when hydraulic oil is supplied to the port 39A of the hydraulic cylinder 39, the rod 39F of the hydraulic cylinder 39 rises and one end (point 53) of the link A2 rises. As a result, the spool 41C of the pilot valve 41 is lifted upward. Then, hydraulic oil is supplied from the pilot valve 41 to the speed relay 42, and the piston 42D of the speed relay 42 rises against the urging force of the spring 42E. As the piston 42D moves up, the point 54 of the link A2 moves down. For this reason, the spool 41C is lowered and the supply of hydraulic oil to the port 42A is stopped.

  When the piston 42D of the speed relay 42 is raised, when one end (point 43) of the link A4 is raised, the other end (point 44) is lowered and the one end (point 45) side of the link A6 is lifted. Thus, when the spool 48C of the servo motor 48 is lifted, the hydraulic oil is supplied to the A chamber 48A, and the rod 48F is lowered.

  As a result, the rod 48F is lowered to transmit power in the order of the arm C1, the rod C3, and the arm C2, and as a result, the steam control valve 32 is lifted (opening operation). On the other hand, when the servo motor 48 is lowered, the other end (point 47) of the link A6 is lowered. As a result, the spool 48C is pushed down, and the supply of hydraulic oil to the A chamber 48A is stopped. Thereby, the steam control valve 32 stops and it becomes the target opening. In order to close the steam control valve 32, a control signal may be output from the control device 37 to the servo valve 38, and hydraulic oil may be supplied to the port 39B of the hydraulic cylinder 39. Since the operation of each component of the opening / closing mechanism 30 in this case is the reverse of the operation when the steam control valve 32 is closed, the description thereof is omitted.

  In the control device 37, the steam control valve 32 is opened by increasing the target opening. During the above operation, the control device 37 causes the first deviation between the target opening of the steam control valve 32 and the actual opening (displacement of the differential transformer 56), and the target opening of the hydraulic cylinder 39 and the actual displacement. The second deviation from the displacement of the differential transformer 55 is monitored.

  As described above, the amount of steam supplied from the nuclear reactor 11 is increased, and at the same time, the amount of water supplied by the water supply pumps 16a and 16b (the opening of the steam control valve) is increased. As a result, the output of the power generation turbine 12 is increased and the power generation amount is increased while the water level in the nuclear reactor 11 is kept within a certain range.

(4) When an abnormality occurs in the opening / closing mechanism 30 Next, an operation when an abnormality occurs in the opening / closing mechanism 30 while the steam control valve 32 is being opened will be described, and the opening degree monitoring method of the present embodiment will be described. explain.
(4-1) Case 1 (when only alarm device 70A is activated)
In the middle of opening the steam control valve 32, if the piston 42D and the cylinder (cylinder of the speed relay 42) are fixed, the operation of the rod 42F is restricted even if the hydraulic cylinder 39 is operated. For this reason, the links A3 to A6 and B2 to B4 do not operate and the arm C1 is not displaced. For this reason, while the target opening degree of the steam control valve 32 increases, the displacement of the differential transformer 56 remains constant, and thus the first deviation described above increases. When the state where the first deviation exceeds 20% (first set value) continues for 2 seconds (first predetermined time) or longer, the control device 37 activates the alarm device 70A. The piston 42D and the cylinder are fixed by, for example, wear powder generated by sliding entering the sliding portion of the speed relay 42 between the piston 42D and the cylinder.

  On the other hand, as shown in FIG. 3, even when the piston 42D and the cylinder are fixed (the speed relay 42 is fixed), the links A1, A2, and B1 are operable around the point 54 of the link A2. Yes (two-dot chain line in FIG. 3). For this reason, the hydraulic cylinder 39 is displaced following the target displacement regardless of whether the speed relay 42 is fixed. For this reason, since the second deviation does not increase, the second set value is not exceeded, and the alarm device 70B does not operate.

  Examples of the case where only the alarm device 70A operates as described above include, for example, a case where the spool 48C of the servo motor 48 does not operate normally due to the fixing of the link A6 in addition to the fixing of the speed relay 42.

(4-2) Case 2 (when both alarm device 70A and alarm device 70B operate)
A case where the hydraulic cylinder 39 malfunctions while the steam control valve 32 is being opened will be described next. In this case, while the target displacement of the hydraulic cylinder 39 increases, the displacement of the differential transformer 55 remains constant, so the second deviation increases. When the state where the second deviation is 15% (second set value) or more continues for 7 seconds (second predetermined time) or longer, the control device 37 activates the alarm device 70B.

  On the other hand, when the hydraulic cylinder 39 does not operate, the link mechanism 31 also does not operate, so that the displacement of the differential transformer 56 remains constant as the target opening of the steam control valve 32 increases. For this reason, the first deviation also increases. When the state where the first deviation is 20% (first set value) or more continues for 2 seconds (first predetermined time) or more, the control device 37 activates the alarm device 70A. As described above, when the hydraulic cylinder 39 malfunctions, both the alarm devices 70A and 70B are activated.

  As described above, in this embodiment, the deviation (first deviation) between the opening of the steam control valve 32 (in this embodiment, proportional to the displacement of the arm C1) and the target opening is equal to or greater than the set value. In this case, the alarm device 70 </ b> A operates to notify the operator of an abnormal operation of the opening / closing mechanism 30. Thus, the operator can quickly respond to the operation abnormality.

  Furthermore, if both the alarm device 70 </ b> A and the alarm device 70 </ b> B are activated, it can be estimated that the poor opening degree of the steam control valve 32 is due to the malfunction of the hydraulic cylinder 39. For this reason, the operator assumes that an abnormality has occurred at a location (servo valve 38, hydraulic cylinder 39, pilot valve 41, link A1-2, etc.) that affects the operation of the hydraulic cylinder 39, and investigated the location where the abnormality occurred. do it.

  Further, when only the alarm device 70A is activated, it is assumed that the hydraulic cylinder 39 is operating normally. Therefore, the operator is not in a part of the opening / closing mechanism 30 that affects the operation of the hydraulic cylinder 39. It is possible to estimate that an abnormality has occurred and investigate the location of the abnormality.

  From the above, the operator can narrow down the locations where an abnormality has occurred from the operation of the alarm devices 70A and 70B. For this reason, it is possible to shorten the time required to identify the abnormal part, and to respond more quickly. Thereby, before the first deviation becomes the trip set value, it is possible to remove the cause of the abnormality and prevent the feed water pumps 16a and 16b from tripping (emergency stop).

  Moreover, it is set as the structure which activates each corresponding alarm device, only when the 1st deviation and the 2nd deviation continue each predetermined time and each setting value is exceeded. For this reason, during the operation of the opening / closing mechanism 30 of the steam control valve 32, each alarm device is caused by an instantaneous increase in deviation (for example, a deviation caused by a delay in hydraulic power transmission, etc.) that is not caused by an abnormality in the opening / closing mechanism 30. Operation can be prevented. For this reason, only when an abnormality occurs in the opening / closing mechanism 30, each alarm device 70A, 70B operates, and the operator can surely know the occurrence of the abnormality.

<Other embodiments>
The present invention is not limited to the embodiments described with reference to the above description and drawings. For example, the following embodiments are also included in the technical scope of the present invention.

  (1) In the above embodiment, the differential transformer is installed in the arm C1 and the displacement is acquired as the opening degree of the steam control valve 32. However, the present invention is not limited to this. A differential transformer may be provided at another location, or a differential transformer may be installed on the arm C2 so that the displacement is acquired as the opening degree of the steam control valve 32.

  (2) The first set value, the second set value, the first predetermined time, and the second predetermined time are not limited to the values in the above embodiment. It can be arbitrarily set from the first and second deviation data measured during normal operation of the power plant.

  (3) In the said embodiment, although the nuclear power plant S was illustrated as a power plant, it is not limited to this. For example, the present invention may be applied to monitoring a steam control valve attached to a turbine drive pump of a thermal power plant.

  (4) Although the opening degree (displacement) of the steam control valve 32 and the displacement of the hydraulic cylinder 39 are acquired by the differential transformer in the above embodiment, the present invention is not limited to this. For example, each displacement may be acquired with a linear encoder or the like.

  (5) In the above embodiment, the controller 37 determines whether the first deviation reaches the trip set value (Condition 1), and the controller 81 determines that the reactor water level is within the set water level range. It was determined whether there was (Condition 2). And based on the conditions 1 and 2, it was set as the structure which stops the driving | operation of the water supply pump 16 in the control apparatus 80, and switches to the driving | operation of the water supply pump 17. FIG. Without being limited to the above configuration, for example, the condition 1 and the condition 2 are determined by one control device, and the operation of the water supply pump 16 is stopped based on the determination result, and the operation is switched to the operation of the water supply pump 17. It is good also as a structure.

16a, 16b ... water supply pumps 20a, 20b ... turbine 30 ... open / close mechanism 32 ... steam control valve 38 ... servo valve (first valve)
39 ... Hydraulic cylinder (first hydraulic actuator)
48B ... Spool valve (second valve)
48 ... Servo motor (second hydraulic actuator)
70A ... Alarm device (first alarm device)
70B ... Alarm device (second alarm device)
S ... Nuclear power plant (power plant)

Claims (3)

In a power plant, a method for monitoring the opening of a steam control valve that increases or decreases the amount of steam supplied to a turbine that drives a feedwater pump,
A method for monitoring an opening degree of a steam control valve, comprising: operating a first alarm device on condition that a first deviation between an opening degree of the steam control valve and a target opening degree is equal to or greater than a first set value. The opening degree monitoring method for the steam control valve according to claim 1,
An opening / closing mechanism for opening / closing the steam control valve,
A first valve that opens and closes by an electrical signal;
A first hydraulic actuator that operates by hydraulic fluid supplied by opening the first valve;
A second valve that is opened and closed by the operation of the first hydraulic actuator;
In an electrohydraulic control type that is configured by a second hydraulic actuator that operates by hydraulic oil supplied by opening the second valve and opens and closes the steam control valve,
A method for monitoring an opening degree of a steam control valve, wherein the second alarm device is operated on the condition that a second deviation between a displacement of the first hydraulic actuator and a target displacement is a second set value or more. A method of monitoring an opening degree of a steam control valve according to claim 2,
The first alarm is activated on the condition that the first deviation continues for a preset first predetermined time and becomes equal to or greater than the first set value,
The opening of the steam control valve, wherein the second alarm device is operated on condition that the second deviation is continuously equal to or greater than the second set value for a preset second predetermined time. Monitoring method.

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