JP2013036404A - Steam turbine system and method of switching operating state of protective device for the steam turbine system - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a steam turbine system capable of securing stable operation of a steam turbine, and a method of switching an operating state of a protective device for the steam turbine system.SOLUTION: The steam turbine system includes: a condenser vacuum trip device 102a for the steam turbine 100; a protective device operating state switching part 30 selectively switching the condenser vacuum trip device 102a between a first operating state for monitoring an operating state of the steam turbine 100 and a second operating state for receiving operation inspection; a pressure sensing part 20 sensing a vacuum degree of a condenser 130 all the time; an auxiliary machine 100a controlling the operation of the steam turbine 100; and a control part controlling operations of the auxiliary machine 100a and the protective device operating state switching part 30 independently. The control part maintains the protective device 102 in the second operating state until decline to a first reference value, and stops the operation of the auxiliary machine 100a when sensing increase to a second reference value. Thus, the first reference value can be set independently of the second reference value, so as to achieve efficient operation inspection and stable operation of the steam turbine 100.

Description

  The present invention relates to a steam turbine system and a steam turbine system safety device operation state switching method, and more particularly to a thermal turbine or nuclear power plant generator steam turbine system and a steam turbine safety device operation state switching method.

  For example, a steam turbine system of a thermal power plant is connected to a main steam stop valve and a steam control valve of the steam turbine, and when an abnormality occurs in the steam turbine, the valves are closed to operate the steam turbine. Equipped with an emergency stop safety device. A steam turbine system having such a security device will be described with reference to FIG.

  As illustrated, the safety device 102 provided in the steam turbine system 110 includes a plurality of devices such as a condenser vacuum trip device 102a, an emergency governor 102b, and a thrust trip device 102c. This safety device 102 is connected to the steam turbine 100 by a safety device hydraulic system 108 provided with a shut-off valve 112. Further, a steam turbine stop hydraulic system 106 communicating with the safety device hydraulic system 108 via the steam turbine 100 is provided, and the steam turbine stop hydraulic system 106 is provided with a main steam stop valve 104a and a steam control valve 104b. ing. That is, the steam turbine stop hydraulic system 106 and the safety device hydraulic system 108 are communicated with each other when the shut-off valve 112 is open, and the oil pressure of the safety device 102 is transmitted via the safety device hydraulic system 108. Is synchronized with.

  In the normal operation state, the safety device 102 constantly monitors the operating state of the steam turbine 100. When the safety device 102 detects an abnormality of the steam turbine 100 and operates, the hydraulic fluid of the safety device 102 is drained. Thus, the hydraulic pressure of the safety device stop hydraulic system 108 decreases, the hydraulic pressure of the steam turbine stop hydraulic system 106 synchronized with the safety device stop hydraulic system 108 also decreases, and the main steam stop valve 104a and the like are closed.

  The safety device 102 includes a first operation state in which the operation state of the steam turbine 100 is constantly monitored, and a second operation in which an operation inspection is performed that simulates an abnormal situation of the steam turbine 100 even during normal operation of the steam turbine 100. It has a state. The operation check of the safety device 102 is executed by operating the test lever 101 that selectively switches the operation state of the safety device 102 between the first operation state and the second operation state. When the operation state of the safety device is switched to the second operation state by operating the test lever 101, the communication between the steam turbine stop hydraulic system 106 and the safety device hydraulic system 108 is shut off by the shutoff valve 112 and the safety device 102. Is drained, and the hydraulic pressure of the safety device stop hydraulic system 108 is lowered.

  If the test lever 101 is erroneously operated during the operation check of the safety device 102 and the operation state of the safety device 102 is switched to the first operation state, the safety device hydraulic system 108 and the steam turbine stop hydraulic system 106 are switched. In communication with each other, the hydraulic pressure of the steam turbine stop hydraulic system 106 decreases in synchronization with the decrease of the hydraulic pressure of the safety device 102, the main steam stop valve 104a and the steam control valve 104b are closed, and the steam to the steam turbine 100 is blocked. Supply is cut off. As a result, the steam turbine 100 may stop, so-called turbine trip may be caused, and as a result, the generator of the thermal power plant may stop, so-called unit trip. When a unit trip occurs, the power transmission system is disturbed and it takes time to start up, so the power generation efficiency is reduced.

  Therefore, a pressure switch that operates due to a decrease in the hydraulic pressure of the safety device opens the solenoid valve and pressurizes the pressure air into the air cylinder, and the test lever causes the safety device to be in the second operating state by the air cylinder into which the pressure air is pressed. A steam turbine safety device that is held in a position to be in an operation check state and prevents the operation state of the safety device from being switched from the second operation state to the first operation state by operating a test lever during the operation check of the safety device. It has been proposed (see, for example, Patent Document 1).

  On the other hand, for example, in the condenser vacuum trip device, the degree of vacuum of the condenser is always sensed, and the operation state of the condenser vacuum trip device is changed to the second operation state until the degree of vacuum reaches a predetermined reference value. And the operation state of the condenser vacuum trip device is switched from the second operation state to the first operation state after reaching the reference value. Such a steam turbine system will be described with reference to FIG. In FIG. 5, the same components as those in FIG. 4 are denoted by the same reference numerals, and the description thereof is omitted.

  As shown, the steam turbine system 120 includes a vacuum unloader 100a and a condenser vacuum trip device 102a. The vacuum unloader 100a reduces the output of the steam turbine 100 in accordance with the reduction in the vacuum degree of the condenser 130, and functions as an auxiliary machine for the steam turbine 100.

  On the other hand, the condenser vacuum trip device 102a includes a pressure first switch 122 and a pressure second switch 124 that constantly sense the degree of vacuum of the condenser 130 that condenses and condenses steam from the steam turbine 100, and A safety device operating state switching unit 126 is provided that maintains a state in which the operation state of the condenser vacuum trip device 102a is switched from the first operation state to the second operation state by the operation of the test lever 101.

  In the pressure first switch 122, a predetermined degree of vacuum is set in advance as a first reference value, and the operation state of the condenser vacuum trip device 102a is switched to the second operation state by the operation of the test lever 101. When the vacuum degree of the condenser 130 sensed by the pressure first switch 122 decreases to the first reference value, the operation state of the condenser vacuum trip device 102a is switched from the second operation state to the first operation state. The first reference value set in the pressure first switch 122 is also used to stop the operation of the vacuum unloader 100a. Therefore, when the vacuum degree of the condenser 130 sensed by the pressure first switch 122 is lowered to the first reference value, the operation state of the condenser vacuum trip device 102a is switched from the second operation state to the first operation state.

  On the other hand, when the predetermined second degree of vacuum is preset in the second pressure switch 124 as the second reference value, and the degree of vacuum of the condenser 130 sensed by the second pressure switch 124 decreases to the second reference value, the vacuum unloader The operation of 100a is started.

  In the steam turbine system 120, the first reference value is set when the predetermined degree of vacuum detected by the pressure first switch 122 is, for example, 86.6 Kpa, and the predetermined degree of vacuum detected by the pressure second switch 124 is For example, it is assumed that the second reference value is set at 81.5 Kpa. In this case, the operation state of the condenser vacuum trip device 102a is switched to the first operation state, as shown in FIG. 6 (a) illustrating the state transition of the vacuum degree of the condenser. When the vacuum degree of 130 decreases from 91.5 to 98.3 Kpa which is a normal value range to 81.5 Kpa which is the second reference value as shown by the vacuum degree curve V3, the operation of the vacuum unloader 100a is started. . Thereafter, when the degree of vacuum increases and reaches the first reference value of 86.6 Kpa, the operation of the vacuum unloader 100a is stopped.

  On the other hand, the operation state of the condenser vacuum trip device 102a is switched to the second operation state, and the vacuum degree of the condenser 130 is changed from 91.5 to 98.3 Kpa to the first as shown by the vacuum degree curve V4. When the reference value is lowered to 86.6 Kpa, the operation state of the condenser vacuum trip device 102a is switched from the second operation state to the first operation state. Then, as described above, the shut-off valve 112 is operated, the steam turbine stop hydraulic system 106 and the safety device hydraulic system 108 communicate with each other, and the steam turbine stop hydraulic pressure is reduced by the decrease in the hydraulic pressure of the condenser vacuum trip device 102a. The hydraulic pressure of the system 106 decreases. As a result, the supply of steam to the steam turbine 100 may be stopped, causing a turbine trip or a unit trip.

JP-A-5-340206

  According to the steam turbine system 120, as described above, when the operation state of the condenser vacuum trip device 102a is switched to the second operation state, the vacuum degree of the condenser 130 is the first reference value (86. When the pressure drops to 6 Kpa), the steam turbine 100 may trip the turbine before the operation check of the condenser vacuum trip device 102a is completed. Therefore, the operation state of the condenser vacuum trip device 102a is checked while the operation state of the condenser vacuum trip device 102a is switched from the second operation state to the first operation state to avoid the steam turbine 100 from tripping the turbine. Need to be completed.

  In order to avoid such a situation, as shown in FIG. 6 (b), the first reference value used for maintaining the state where the operation state of the condenser vacuum trip device 102a is switched to the second operation state, For example, it is conceivable to change the setting to a trip value that can hardly be expected to decrease. If such a setting change is performed, it is possible to sufficiently ensure the operation inspection time of the condenser vacuum trip device 102a while avoiding the turbine trip of the steam turbine 100.

  However, the first reference value is used not only to maintain the state in which the operation state of the condenser vacuum trip device 102a is switched to the second operation state, but also to stop the operation of the vacuum unloader 100a. ing. Therefore, if the degree of vacuum set to the first reference value is changed, the conditions for maintaining the second operation state and operating control of the vacuum unloader 100a are simultaneously changed. That is, the operation control conditions of the vacuum unloader 100a that do not need to be changed are changed. For example, the operation state of the condenser vacuum trip device 102a is switched to the second operation state, and the vacuum degree of the condenser 130 is 91.5 as shown by the vacuum degree curve V5 in FIG. When the value falls to 81.5 Kpa which is the second reference value from the range of ˜98.3 Kpa, the operation of the vacuum unloader 100a starts, but then the degree of vacuum rises and reaches the first reference value of 86.6 Kpa. However, the operation of the vacuum unloader 100a is not stopped, and an accurate operation check of the condenser vacuum trip device 102a cannot be realized.

  The present invention has been made in view of the above problems, and an object of the present invention is to provide a steam turbine system capable of ensuring stable operation of the steam turbine and a method for switching the operating state of the safety device of the steam turbine system. There is to do.

  In order to achieve the above object, a steam turbine system according to the first aspect of the present invention includes a steam turbine and a steam turbine based on the degree of vacuum of the steam turbine and a condenser for condensing the steam from the steam turbine to condense. A safety device that monitors the operating state, a pressure sensing unit that is provided in the safety device and constantly senses the degree of vacuum of the condenser, and the vacuum that senses the operating state of the safety device by the pressure sensing unit. Selectable between a first operating state in which the steam turbine is tripped when a degree falls from a normal value range to a preset trip value and a second operating state in which an operation check is performed while sensing the degree of vacuum A safety device operating state switching unit for switching to an auxiliary device, an auxiliary device for controlling an operating state of the steam turbine according to a change in the degree of vacuum sensed by the pressure sensing unit, on / off of the operation of the auxiliary device, and the security A control unit that independently controls the switching by the stationary operation state switching unit, and the control unit switches the operation state of the safety device to the second operation state by the safety device operation state switching unit. The safety device is held in the second operating state until the degree of vacuum drops to a first reference value set in advance, and the operating state of the safety device is changed by the safety device operating state switching unit. The operation of the auxiliary machine is stopped when the degree of vacuum rises to a second reference value set in advance to a value higher than the first reference value while being switched to the two operation state. To do.

  According to this configuration, the control unit controls the switching of the safety device operating state switching unit based on the first reference value, and the operation of the auxiliary machine is stopped based on the second reference value different from the first reference value. Therefore, the first reference value can be set within a relatively wide range of the vacuum degree of the condenser independently of the second reference value. Accordingly, since the first reference value can be set so as to prevent the operation state of the security device from being switched from the second operation state to the first operation state, it is efficient without interrupting the operation check of the security device. As a result, stable steam turbine operation can be realized.

  A steam turbine system according to a second aspect of the present invention is the steam turbine system according to the first aspect, wherein the first reference value is set to the same value as the trip value.

  According to this configuration, since the first reference value is set to a trip value that can hardly be expected to decrease, the time required for the operation check of the security device is ensured for a relatively long time. Can do. Thus, the operation of the safety device can be executed without interruption, and the operation of claim 1 can be effectively realized in which stable operation of the steam turbine is realized.

  A steam turbine system according to a third aspect of the present invention is the steam turbine system according to the first or second aspect, wherein the pressure sensing unit includes a pressure first switch and a pressure second switch, and the pressure first switch includes The first reference value is set, and the second reference value is set in the pressure second switch.

  This configuration specifically clarifies the configuration of the pressure sensing unit according to claim 1 or 2, and the security device in which the first reference value is used as the control value by a simple configuration using two pressure switches. Easily set the first reference value and the second reference value as the control values so that the operation state switching unit and the operation stop of the auxiliary machine in which the second reference value is used as the control value are independently controlled. Can do.

  The steam turbine system according to claim 4 is the steam turbine system according to any one of claims 1 to 3, wherein the pressure sensing unit is higher than the first reference value and higher than the second reference value. A pressure third switch having a third reference value set in advance to a lower value, wherein the control unit senses that the degree of vacuum has decreased to the third reference value by the pressure third switch. When the operation is performed, the operation of the auxiliary machine is started.

  According to this configuration, the operation of the auxiliary device can be performed independently of the switching of the operating state of the safety device and the stoppage of the auxiliary device by a simple configuration in which the third reference value as the control value is set in the third pressure switch. The third reference value as the control value can be set independently so as to start the process.

  The operation switching method of the safety device of the steam turbine system according to the invention described in claim 5 monitors the operating state of the steam turbine based on the degree of vacuum of a condenser for condensing the steam from the steam turbine to condense. The operating state of the safety device is lowered from the normal value range to a preset trip value, which is detected by a pressure sensing unit provided in the safety device and constantly detecting the vacuum level of the condenser. And selectively switching between a first operating state in which the steam turbine is tripped and a second operating state in which operation check is performed while sensing the degree of vacuum, and the operating state of the safety device is changed to the second operating state. The safety device is held in the second operating state until the degree of vacuum drops to a preset first reference value in the switched state, and the operating state of the safety device is switched to the second operating state. When the degree of vacuum rises to a second reference value set in advance to a value higher than the first reference value, the operation of the auxiliary machine is stopped, the range of normal values and the trip value In this range, the first reference value is set independently from the second reference value.

  According to this method, since the first reference value can be set only within the range of the normal value and the trip value after the first reference value is used solely for switching control of the operating state of the safety device, the safety device The first reference value can be easily changed so as to ensure the optimum time for the operation check according to the individual specific configuration.

  According to this invention, since the first reference value can be set independently from the second reference value, the operation state of the safety device is switched from the second operation state to the first operation state during the operation check of the safety device. The first reference value can be set so as to prevent it from being generated. Thereby, the operation check of the security device can be executed efficiently without being interrupted. As a result, for example, when the steam turbine system according to the present invention is applied to a generator, it is possible to prevent the steam turbine from tripping the turbine and further to prevent the generator from unit tripping. This makes it possible to reduce the cause of the unit trip and to realize stable operation of the generator.

It is a figure explaining the outline of the steam turbine system concerning an embodiment of the invention. It is a flowchart explaining the operating state of the steam turbine system which concerns on this Embodiment. Similarly, it is a figure explaining the operating state of the steam turbine system concerning this embodiment. It is a figure explaining the outline of the operation check of the conventional steam turbine safety device. Similarly, it is a figure explaining the outline of the conventional steam turbine system. Similarly, it is a figure explaining the operating state of the conventional steam turbine system.

  Next, an embodiment of the present invention will be described with reference to FIGS. In the present embodiment, a case where the steam turbine system is provided in a generator of a thermal power plant will be described as an example. Moreover, in FIGS. 1-3, the same code | symbol is attached | subjected to the component similar to FIG.5 and FIG.6, and the description is abbreviate | omitted.

  FIG. 1 is a diagram illustrating an outline of a steam turbine system according to an embodiment of the present invention. As illustrated, a steam turbine system (hereinafter simply referred to as “system 10”) includes a steam turbine 100 that operates a generator of a thermal power plant, and a condenser that condenses the steam from the steam turbine 100 to condense. A safety device is provided for tripping the steam turbine 100 when the degree of vacuum of 130 drops from a normal value range to a trip value. The security device is configured as a condenser vacuum trip device 12 in the present embodiment. Furthermore, the system 10 is an auxiliary machine that controls the operation state of the steam turbine 100 according to the fluctuation of the vacuum degree of the condenser 130. In the present embodiment, the steam turbine 100 when the vacuum degree of the condenser 130 is lowered. Is provided with a vacuum unloader 100a.

  The condenser vacuum trip device 12 includes a pressure sensing unit 20 that constantly senses the degree of vacuum of the condenser 130 and a safety device operating state switching unit 30. The operation state of the condenser vacuum trip device 12 is a first operation state which is a normal operation state in which the operation state of the steam turbine 100 is monitored based on the vacuum degree of the condenser 130 detected by the pressure sensor 20. And the second operation state in which the condenser vacuum trip device 12 itself is inspected for operation while sensing the vacuum degree of the condenser 130, and selectively switched by the safety device operation state switching unit 30. The safety device operating state switching unit 30 is configured so that the pressure sensing unit 20 is in a vacuum of the condenser 130 while the operation state of the condenser vacuum trip device 12 is switched to the second operation state by the operation of the test lever 101. When it is sensed that the degree has decreased from a normal value range to a first reference value, which will be described later, in this embodiment, a trip value, the operation state of the condenser vacuum trip device 12 is changed from the second operation state to the first operation state. Switch.

  The operation of the safety device operating state switching unit 30 and the vacuum unloader 100a is controlled by a control unit configured by the pressure sensing unit 20 and the vacuum unloader control unit 40. The vacuum unloader control unit 40 is configured to stop the operation of the vacuum unloader 100a when the pressure sensing unit 20 senses that the vacuum level of the condenser 130 has increased to a second reference value described later.

  Next, a specific configuration of the system 10 in the present embodiment will be described.

  In this embodiment, the pressure sensing unit 20 includes a pressure first switch 22, a pressure second switch 24, and a pressure third switch 26. The first pressure switch 22 is connected to the condenser 130 via the pressure valve 22a to constantly sense the vacuum degree of the condenser 130, and the sensed vacuum degree of the condenser 130 is within a normal value range. The first reference value is preset to a lower predetermined value. The first pressure switch 22 is electrically connected to the safety device operating state switching unit 30. The safety device operating state switching unit 30 is connected to a first relay switch 32a electrically connected to the pressure first switch 22, an electromagnetic valve 34 electrically connected to the first relay switch 32a, and an electromagnetic valve 34. An air cylinder 36 that is pressurized and depressurized by an air pump unit (not shown) by opening and closing the electromagnetic valve 34 is provided. The air cylinder 36 includes a piston 36c that divides the air cylinder 36 into a first cylinder chamber 36a and a second cylinder chamber 36b. The piston 36c is connected to the test lever 101 via a link mechanism 36d.

  The safety device operating state switching unit 30 is further provided with a second relay switch 32b arranged in parallel with the first relay switch 32a and electrically connected to the test lever 101. The second relay switch 32b is connected to a limit switch (not shown) provided on the test lever 101. When the test lever 101 is switched to the second operating state side, the limit switch is activated and the second relay switch 32b is turned on. When excited, an electric signal is input to the electromagnetic valve 34.

  The pressure second switch 24 is connected to the condenser 130 via the pressure valve 24a to constantly sense the vacuum degree of the condenser 130, and the sensed vacuum degree of the condenser 130 is lower than the normal value range. The second reference value is preset to a predetermined value that is lower and higher than the first reference value. The pressure second switch 24 has a pressure transmission function for converting the detected vacuum degree of the condenser 130 into an analog transmission signal and transmitting the analog transmission signal, and a turbine sequencer controller for controlling the operating state of the steam turbine 100 The sequence control of the turbine sequencer control unit 100b is executed based on the degree of vacuum of the condenser 130 that is electrically connected to 100b and sensed by the pressure second switch 24. On the other hand, the pressure second switch 24 is electrically connected to the vacuum unloader control unit 40 separately from the turbine sequencer control unit 100b.

  The vacuum unloader control unit 40 includes a high / low switch 42 electrically connected to the pressure second switch 24 and a set / reset determination unit 44 electrically connected from the high / low switch 42. A logic circuit is incorporated in the high / low switch 42, and an electrical signal transmitted by the pressure transmission function of the pressure second switch 24 is input to the high / low switch 42, and an analog signal is converted into a digital signal by the logic circuit of the high / low switch 42. And input to the set / reset determination unit 44. The set / reset determination unit 44 is electrically connected to the vacuum unloader 100 a, and the vacuum unloader 100 a is connected to the steam turbine 100.

  The pressure third switch 26 is connected to the condenser 130 via the pressure valve 22a to constantly sense the vacuum degree of the condenser 130, and the sensed vacuum degree of the condenser 130 is lower than the first reference value. The third reference value is set in advance to a predetermined value that is higher and lower than the second reference value. The pressure third switch 26 is electrically connected to the set / reset determination unit 44 of the vacuum unloader control unit 40.

  The vacuum unloader control unit 40 is configured to start the operation of the vacuum unloader 100a when the pressure third switch 26 senses that the vacuum degree of the condenser 130 has decreased to the third reference value. That is, the vacuum unloader control unit 40 is configured to control operation start and stop of the vacuum unloader 100a.

  Next, the operation and operation status of the system 10 according to the present embodiment when the operation state of the condenser vacuum trip device 12 is set to the second operation state will be described. In the present embodiment, the case where the trip value as the first reference value is set to 70.6 Kpa, the second reference value is set to 86.6 Kpa, and the third reference value is set to 81.5 Kpa will be described as an example.

  Here, the range of the normal value of the vacuum degree of the condenser 130 is normally 91.5 Kpa to 98.3 Kpa. However, for example, when the vacuum degree is likely to decrease, such as in summer, the normal degree of vacuum is It decreases by about several Kpa.

  FIG. 2 is a flowchart for explaining the operating state of the system 10, and FIG. 3 is a diagram for explaining the operating state of the system 10 according to the degree of vacuum of the condenser 130. As shown in the figure, first, the test lever 101 is operated to switch the operation state of the condenser vacuum trip device 12 from the first operation state to the second operation state (step S1: test lever operation step). As a result, the hydraulic oil of the condenser vacuum trip device 12 is drained and the hydraulic pressure of the safety device hydraulic system 108 is lowered, and a limit switch (not shown) provided on the test lever 101 is operated and the safety device is operated by the shutoff valve 112. The communication state between the hydraulic system 108 and the steam turbine stop hydraulic system 106 is interrupted. On the other hand, the operation state of the steam turbine 100 is maintained.

  When the operation state of the condenser vacuum trip device 12 is switched to the second operation state by operating the test lever 101, the piston 36a of the air cylinder 36 moves in the pressure-reducing direction of the second cylinder chamber 36b, and the test lever 101 The provided limit switch (not shown) is activated, the second relay switch 32b of the safety device operating state switching unit 30 is excited, and the electromagnetic valve 34 is activated. If it does so, pressurization air will be supplied to the 1st cylinder chamber 36a via the solenoid valve 34 from the air pump unit which is not illustrated, and the 1st cylinder chamber 36a will be pressurized. On the other hand, by the operation of the electromagnetic valve 34, the pressurized air is discharged from the second cylinder chamber 36b through the electromagnetic valve 34, and the second cylinder chamber 36b is decompressed. Thereby, the test lever 101 is held in a state where the operation state of the condenser vacuum trip device 12 is switched to the second operation state, and the operation check of the condenser vacuum trip device 12 is started (step S2: Operation check start process).

  When it is sensed by the pressure first switch 22 that the vacuum degree of the condenser 130 immediately after the start of the operation check is within a normal value range of 91.5 Kpa to 98.3 Kpa (step S3: vacuum degree detection) In the first step, the pressure first switch 22 senses that the degree of vacuum has not decreased from the normal value range even after a predetermined time has elapsed since the start of the operation check (step S4: second degree of vacuum sensing). When the operation inspection is completed in the process) state, the operator operates the test lever 101 to switch the operation state of the condenser vacuum trip device 12 from the second operation state to the first operation state (step S5: operation inspection). End process).

  The operation of the test lever 101 is performed according to the following procedure. First, when an operator operates a reset switch (not shown), the excitation of the second relay switch 32b is released and the electromagnetic valve 34 is activated. Then, the pressurized air is discharged from the first cylinder chamber 36a via the electromagnetic valve 34. As a result, the test lever 101 can be operated, so that the test lever 101 is operated to switch the operation state of the condenser vacuum trip device 12 from the second operation state to the first operation state. When the test lever 101 is operated, a limit switch (not shown) provided on the test lever 101 is activated, the first relay switch 32a of the safety device operating state switching unit 30 is excited, and the electromagnetic valve 34 is activated. If it does so, pressurization air will be supplied to the 2nd cylinder chamber 36b via the solenoid valve 34 from the air pump unit which is not illustrated, and the 2nd cylinder chamber 36b will be pressurized.

  When the operation state of the condenser vacuum trip device 12 is switched from the second operation state to the first operation state, hydraulic oil is supplied to the condenser vacuum trip device 12 and the hydraulic pressure of the safety device hydraulic system 108 increases. At the same time, a limit switch (not shown) provided in the test lever 101 is operated, and the shutoff valve 112 establishes communication between the safety device hydraulic system 108 and the steam turbine stop hydraulic system 106. Thereby, the condenser vacuum trip device 12 returns to the first operation state.

  On the other hand, after the start of the operation check, it is sensed that the vacuum degree of the condenser 130 has fallen from the normal value range (step S3: first degree of vacuum sensing step). When 81.5 Kpa, which is the third reference value set in the pressure third switch 26, is sensed (step S6: third reference value sensing step), an electrical signal is sent from the pressure third switch 26 to the set / reset determination unit 44. Is input, and the set / reset determination unit 44 determines to start the operation of the vacuum unloader 100a (step S7: vacuum unloader operation start step). Thereby, when the operation of the vacuum unloader 100a is started, the supply of steam to the steam turbine 100 is suppressed in accordance with the decrease in the vacuum degree of the condenser 130, and the efficiency according to the reduced vacuum degree of the condenser 130 is reduced. Operation of the steam turbine 100 is realized.

  After the operation of the vacuum unloader 100a is started, the vacuum degree of the condenser 130 increases as shown by the vacuum degree curve V1 in FIG. 3, and for example, the pressure second switch 24 is set to the pressure second switch 24. When the second reference value of 86.6 Kpa is sensed (step S8: second reference value sensing step), an analog signal is input from the pressure second switch 24 to the high / low switch. The analog signal is logically processed by the high / low switch 42 and converted into a digital signal, and then the digital signal is input to the set / reset determination unit 44. The set / reset determination unit 44 determines that the operation of the vacuum unloader 100a is to be stopped by the input digital signal, and the operation of the vacuum unloader 100a is stopped (step S9: vacuum unloader operation stop process).

  Therefore, since only the first reference value as the lowest limit value for holding the test lever 101 on the second operating state side is set in the pressure first switch 22, the vacuum used for other reference values is set. The first reference value can be set within a relatively wide vacuum range without considering the occurrence of mutual interference with the degree. In particular, in this embodiment, since the first reference value is set to 70.6 Kpa, which is a trip value that cannot be assumed to decrease, the operation state of the condenser vacuum trip device 12 is the second. It is possible to prevent the operation state from being switched to the first operation state, complete the operation check of the condenser vacuum trip device 12 without interruption, and realize a stable and efficient operation check. it can. As a result, the simple configuration in which only the first reference value is set in the pressure first switch 22 can prevent the steam turbine 100 from tripping the turbine and further the unit from tripping the generator. It is possible to reduce the cause of the unit trip, and the generator can be operated efficiently and stably.

  On the other hand, for example, when the degree of vacuum is likely to decrease, such as in summer, the degree of vacuum of the condenser 130 decreases after the start of the operation check, and it is detected that the degree of vacuum after the start of the operation check is not within the normal range. In this case (step S4: vacuum degree sensing second step), the vacuum degree is further lowered as shown by the vacuum degree curve V2 in FIG. 3, and the pressure first switch 20 is temporarily set to the pressure first switch 20. When the trip value of 70.6 Kpa, which is the first reference value, is sensed (step S10: first reference value sensing step), the first relay switch 32a is energized and the electromagnetic valve 34 is actuated, and the first cylinder is activated. The press-in air is discharged from the chamber 36a, and the press-in air is supplied to the second cylinder chamber 36b. Thereby, the operation state of the condenser vacuum trip device 12 is switched from the second operation state to the first operation state. Then, the limit switch provided in the test lever 101 is operated, the shut-off valve 112 is operated, and the safety device hydraulic system 108 and the turbine stop hydraulic system 106 are brought into communication with each other. 12 returns to the first operation state, which is a normal operation state (step S11: security device operation state switching step).

  Therefore, even if the steam turbine 100 trips due to the vacuum degree decreasing and reaching the trip value during the operation check of the condenser vacuum trip device 12, the condenser vacuum trip device is simultaneously performed with the turbine trip. Since the operation state of 12 is switched from the second operation state to the first operation state, the operator forgets to operate the test lever 101 when performing the recovery operation of the steam turbine 100, and the condenser vacuum trip device 12. It is possible to prevent an erroneous operation such that the steam turbine 100 is restored while the operation state is the second operation state, and it is possible to appropriately prevent the unit trip of the generator from being caused again.

  In addition, this invention is not limited to the said embodiment, A various change is possible in the range which does not deviate from the meaning of invention. For example, in the above-described embodiment, the case where the system 10 is configured using the condenser vacuum trip device 12 in the generator of the thermal power plant has been described as an example, but the condenser in the generator of the nuclear power plant is described. It may be a steam turbine system configured using a vacuum trip device.

DESCRIPTION OF SYMBOLS 10 Steam turbine system 12, 102a Condenser vacuum trip apparatus 20 Pressure sensing part 22 Pressure 1st switch 24 Pressure 2nd switch 26 Pressure 3rd switch 30 Safety device operating state switching part 40 Vacuum unloader control part 44 High / low switch 100 Steam turbine 101 Test lever 100a Vacuum unloader 102 Security device 112 Shut-off valve 130 Condenser

Claims (5)

A steam turbine;
A safety device that monitors the operating state of the steam turbine based on the degree of vacuum of a condenser that condenses and condenses steam from the steam turbine;
A pressure sensing unit provided in the security device to constantly sense the degree of vacuum of the condenser;
The operating state of the safety device is a first operating state in which the steam turbine is tripped when the degree of vacuum detected by the pressure sensing unit falls from a normal value range to a preset trip value, and the degree of vacuum. A safety device operating state switching unit that selectively switches between a second operating state that receives an operation check while sensing
An auxiliary machine that controls the operating state of the steam turbine according to the variation in the degree of vacuum sensed by the pressure sensing unit;
A control unit for independently controlling on / off of the operation of the auxiliary machine and the switching by the safety device operating state switching unit,
The control unit
The safety device is moved to the second reference state in a state where the operation state of the safety device is switched to the second operation state by the safety device operation state switching unit until the second degree of vacuum is lowered to the preset first reference value. Keep it running,
In a state where the operating state of the safety device is switched to the second operating state by the safety device operating state switching unit, the degree of vacuum is set to a second reference value preset to a value higher than the first reference value. Stop the operation of the accessory when it rises,
A steam turbine system characterized by that.   The steam turbine system according to claim 1, wherein the first reference value is set to the same value as the trip value. The pressure sensing unit is
A pressure first switch and a pressure second switch;
The steam turbine system according to claim 1 or 2, wherein the first reference value is set in the first pressure switch, and the second reference value is set in the second pressure switch. The pressure sensing unit is
A pressure third switch in which a third reference value that is preset to a value that is higher than the first reference value and lower than the second reference value is set;
The controller is
Starting the operation of the auxiliary device when the third pressure switch senses that the degree of vacuum has dropped to the third reference value;
The steam turbine system according to any one of claims 1 to 3. An operating state of a safety device that monitors an operating state of the steam turbine based on a vacuum degree of a condenser that condenses the steam from the steam turbine and condenses, is provided in the safety device, and the vacuum of the condenser A first operating state in which the steam turbine is tripped when the degree of vacuum detected by a pressure sensing unit that constantly senses the degree falls from a normal value range to a preset trip value, while sensing the degree of vacuum. Selectively switch between the second operating state to receive operation check,
Holding the safety device in the second operating state until the degree of vacuum drops to a preset first reference value in a state where the operating state of the safety device is switched to the second operating state;
When the vacuum level rises to a second reference value preset to a value higher than the first reference value while the operating state of the safety device is switched to the second operating state, Stop working,
An operation state switching method for a safety device of a steam turbine system, wherein the first reference value is set independently from the second reference value in a range between the normal value range and the trip value.

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