Emergency trip device for steam turbine

Abstract

To prevent hunting of an emergency trip device for a steam turbine when recovering from a tripped state.SOLUTION: According to an embodiment, an emergency trip device 100 for a steam turbine causes the loss of emergency oil pressure in a steam valve 10 by an emergency trip signal. The emergency trip device 100 comprises: an emergency oil pipe 110; an upstream switching valve 110x having an A port and a B port with the A port connected to the emergency oil pipe 110; an oil drain pipe 130 for discharging emergency oil; a downstream switching valve 130x having an A port and a B port with the A port connected to the oil drain pipe 130; a connection pipe 140 connecting the B port of the upstream switching valve to the B port of the downstream switching valve; a trip solenoid valve 120a that can switch between a connection state with the upstream switching valve and a connection state with the oil drain pipe; and an emergency oil supply stop unit 160 provided in the emergency oil pipe 110.SELECTED DRAWING: Figure 2

Description

[Technical Field]

[0001] SUMMARY OF THE INVENTION An embodiment of the present invention relates to an emergency trip device for a steam turbine. [Background technology]

[0002] Fig. 11 is a system diagram showing an example of the configuration of a conventional emergency trip device. The emergency trip device configures a path for emergency oil to be supplied from an oil supply source to steam valves 10 such as the main steam stop valve and steam control valve of a steam turbine.

[0003] During operation of the steam turbine, the steam valve is open, and therefore the emergency trip device is in a state where emergency oil pressure is maintained. On the other hand, when an emergency trip signal is generated, the emergency trip device transitions to a state where emergency oil pressure is lost. In other words, the emergency oil is connected to the oil discharge side in the emergency trip device, and emergency oil pressure is not maintained. As a result, the steam valve 10 is rapidly closed (suddenly closed). In other words, the steam turbine undergoes an emergency trip. Specifically, the sudden closure of the steam valve prevents the inflow of working steam into the steam turbine, and the steam turbine transitions to a stopped state.

[0004] In this way, the emergency trip device is configured to maintain emergency oil pressure while the steam turbine is operating, and to lose emergency oil pressure according to trip logic when an emergency trip signal is issued from the separately provided turbine protection circuit 5.

[0005] Figure 11 shows the configuration when the trip logic is "2 out of 3." Here, "2 out of 3" refers to logic that does not operate when only one of the three turbine trip signals generated by the emergency trip logic circuit is established, but when two or three of the three signals are established.

[0006] The emergency trip device is configured to correspond to this trip logic, and details will be explained in the embodiments.

[0007] The emergency trip device basically has an emergency oil piping 110, which is a flow path for emergency oil from the oil supply source to the steam valve 10, an oil drain piping 130, which discharges the emergency oil outside the emergency trip device, and various elements for switching the flow path between these two pipes.

[0008] The elements for switching the flow paths include three trip solenoid valves 120a indicated by 121a, 122a, and 123a, three pilot pipes 120 indicated by 121, 122, and 123, three upstream switching valves 110x indicated by 111, 112, and 113, three downstream switching valves 130x indicated by 131, 132, and 133, and connecting pipes 140 indicated by 141, 142, and 143 that connect these.

[0009] The upstream-side switching valve 110x and the downstream-side switching valve 130x each have two ports (port A and port B), and each switching valve can switch between a state in which the two ports are connected and a state in which they are blocked. The port A of the upstream-side switching valve 110x is connected to the emergency oil pipe 110. The port A of the downstream-side switching valve 130x is connected to the oil drain pipe 130. The port B of the upstream-side switching valve 110x and the port B of the downstream-side switching valve 130x are connected to each other by a connecting pipe in accordance with a combination corresponding to the trip logic.

[0010] The three trip solenoid valves 120a each receive a turbine trip signal from the turbine trip circuit for each series and operate to transition the interiors of the corresponding upstream switching valves 110x and downstream switching valves 130x to a communication state. The trip solenoid valves 120a are, for example, three-way valves, and this operation is performed in the form of switching the hydraulic circuit. As a result, if the emergency oil piping 110 and the oil drain piping 130 are connected via any of the elements, the hydraulic pressure of the emergency oil supplied to the steam valve 10 will be lost, leading to tripping of the steam turbine. [Prior art documents] [Patent documents]

[0011] [Patent Document 1] Patent No. 7113544 Summary of the Invention [Problem to be solved by the invention]

[0012] As mentioned above, after the turbine trip state is entered, the emergency oil piping 110 and the oil drain piping 130 are connected via each element, so the emergency oil supplied from the oil source continues to flow out of the oil drain piping 130.

[0013] When the steam turbine recovers from the trip state and begins preparation for operation, the emergency trip signal is released. As a result, the trip solenoid valve 120a operates to transition the interiors of the corresponding upstream switching valves 110x and downstream switching valves 130x from a connected state to a cut-off state. The switching of the upstream switching valves 110x and downstream switching valves 130x by the trip solenoid valve 120a is performed hydraulically.

[0014] 11, the downstream switching valves 130x indicated by 131, 132, and 133 are closer to the trip solenoid valves 120a indicated by 121a, 122a, and 123a than the upstream switching valves 110x indicated by 111, 112, and 113. Therefore, the interior of the downstream switching valves 130x transitions from a connected state to a cut-off state earlier than the interior of the upstream switching valve 110x transitions from a connected state to a cut-off state. In other words, the downstream switching valve 130x on the oil discharge side closes earlier than the upstream switching valve 110x on the emergency oil supply side.

[0015] As a result, first, the emergency oil in the connecting pipes indicated by 141, 142, and 143 becomes blocked. Next, the upstream switching valve 110x closes, causing an instantaneous rise in the oil pressure of the emergency oil in the blocked connecting pipes. As a result, the balance between the closing force and the lifting force of the upstream switching valve 110x and the downstream switching valve 130x is lost. For example, these valves may operate at a timing unrelated to the operation of the trip solenoid valve 120a, causing hunting. This results in a problem of losing the soundness and stability of the emergency trip device.

[0016] Therefore, an object of an embodiment of the present invention is to provide an emergency trip device for a steam turbine that does not cause hunting when recovering from a tripped state in the steam turbine. [Means for solving the problem]

[0017] In order to achieve the above object, an emergency trip device for a steam turbine according to this embodiment is an emergency trip device for a steam turbine that receives an emergency trip signal to cause the hydraulic pressure of emergency oil to be lost that is supplied to a steam valve, and that maintains the hydraulic pressure of the emergency oil before the emergency trip signal is generated, and that includes an emergency oil pipe that is connected to an oil supply source and serves as a path for the emergency oil from the oil supply source to the steam valve, a plurality of upstream changeover valves each having an upstream changeover valve A port and an upstream changeover valve B port, and the upstream changeover valve A port being connected to the emergency oil pipe, an oil discharge pipe that discharges the emergency oil, and the downstream switching valves each having an upstream switching valve A port and a downstream switching valve B port, the downstream switching valve A port being connected to the oil drain piping; a plurality of connection piping connecting the upstream switching valve B port of each of the plurality of upstream switching valves to the downstream switching valve B port of each of the plurality of downstream switching valves; a plurality of trip solenoid valves on the upstream side to which the emergency oil is supplied from the emergency oil piping, and on the downstream side which are switchable between a connection state with the plurality of upstream switching valves and a connection state with the oil drain piping; and an emergency oil supply stop unit capable of blocking the flow path of the emergency oil piping. [Brief explanation of the drawings]

[0018] [Figure 1] 1 is a conceptual configuration diagram showing a steam valve and a hydraulic system related to the steam valve to which an emergency trip device according to a first embodiment is applied. [Figure 2] 1 is a system diagram showing the configuration of an emergency trip device according to a first embodiment. [Figure 3] 3 is a conceptual explanatory diagram showing the internal connection of the supply cutoff solenoid valve of the emergency oil supply cutoff unit of the emergency trip device according to the first embodiment in a non-excited state. FIG. [Figure 4] 3 is a conceptual explanatory diagram showing the internal connection of the supply cutoff solenoid valve of the emergency oil supply cutoff unit of the emergency trip device according to the first embodiment in an excited state. FIG. [Figure 5] FIG. 2 is a conceptual explanatory diagram showing a cutoff valve of an emergency oil supply stop unit of the emergency trip device according to the first embodiment. [Figure 6] FIG. 6 is a system diagram showing the configuration of an emergency trip device according to a second embodiment. [Figure 7] FIG. 10 is a conceptual explanatory diagram showing a pilot check valve of an emergency oil supply stop unit of an emergency trip device according to a second embodiment. [Figure 8] FIG. 10 is a system diagram showing the configuration of an emergency trip device according to a third embodiment. [Figure 9] FIG. 11 is a conceptual explanatory diagram showing a state when a spool valve of an emergency oil supply stop unit of an emergency trip device according to a third embodiment is in a communicating state. [Figure 10] FIG. 11 is a conceptual explanatory diagram showing a state when a spool valve of an emergency oil supply stop unit of an emergency trip device according to a third embodiment is shut off. [Figure 11] FIG. 1 is a system diagram showing an example of the configuration of a conventional emergency trip device. DETAILED DESCRIPTION OF THE INVENTION

[0019] Hereinafter, an emergency trip device for a steam turbine according to an embodiment of the present invention will be described with reference to the drawings. Hereinafter, identical or similar parts will be denoted by common reference numerals, and overlapping descriptions will be omitted.

[0020] [First embodiment] FIG. 1 is a conceptual configuration diagram showing a steam valve 10 and a hydraulic system related to the steam valve 10 to which an emergency trip device 100 according to a first embodiment is applied.

[0021] Here, the steam valve 10 refers to a valve that allows the flow of working steam into a steam turbine (not shown) to perform work and stops the flow of steam into the turbine body. That is, it is a stop valve or control valve for the working steam provided at each inlet of the turbine body. The steam valve 10 may be, for example, a main steam stop valve, a steam control valve, or a reheat steam stop valve.

[0022] When an emergency trip signal is generated from the turbine protection circuit 5, which is part of the steam turbine protection device, the steam valve 10 suddenly closes to cut off the flow of operating steam into the steam turbine. Here, an emergency trip refers to an unplanned automatic or manual shutdown of the steam turbine to protect the steam turbine when a condition arises that makes it impossible to continue operating the steam turbine. In other words, an emergency trip refers to stopping the steam turbine in the event of an abnormality, in other words, transitioning the turbine rotor from a rotating state to a stopped state. The emergency trip signal is a signal for causing an emergency trip of the steam turbine. The turbine protection circuit 5, which is part of the steam turbine protection device, determines whether or not there is an abnormality based on detection signals from various parts of the steam turbine and generator, and outputs an emergency trip signal if an abnormality is detected.

[0023] The steam valve 10 has a valve body 11, a valve oil cylinder 12, and a disk dump valve 13. The disk dump valve 13 is connected to an emergency trip device 100 and test solenoid valves 15a and 15b, respectively, for verifying soundness during operation.

[0024] When the steam turbine is in operation, the valve element 11a of the valve body 11 is separated from the valve seat 11b, and the steam valve 10 is fully open or at an intermediate opening (hereinafter referred to as the "open state"). The lower side of the disk 13a in the disk dump valve 13 is connected to an emergency trip device 100.

[0025] When the steam valve 10 is in the open state, emergency oil can be supplied from the emergency trip device 100 to the disk dump valve 13 via the emergency oil piping 110. This ensures that the emergency oil pressure required to maintain the steam valve 10 in the open state is maintained below the disk 13a. Here, the emergency oil is supplied to the steam valve 10 side, specifically the disk dump valve 13, in order to maintain the open state of the steam valve 10 of the steam turbine. When an emergency trip of the steam turbine is required, the supply of emergency oil is stopped and control is performed so that the emergency oil pressure at the disk dump valve 13 is lost. The pressure of the emergency oil is high-pressure oil, for example, exceeding 10 MPa. In other words, the emergency oil is high-pressure oil related to maintaining the opening of the steam valve 10 and performing a quick-closing operation.

[0026] Now, when an emergency trip signal is generated from the turbine protection circuit 5, the flow path within the emergency trip device 100 is switched. Specifically, the emergency trip signal switches from a state in which the disk dump valve 13 is connected to the oil supply source on the emergency oil piping 110 side to a state in which the disk dump valve 13 is connected to the oil drain piping 130.

[0027] As a result, the bottom of the disk 13a in the disk dump valve 13 communicates with the oil drain pipe 130 via the emergency trip device 100, causing a drop or loss of emergency oil pressure. This causes the disk 13a to drop downward, and the oil pressure in the valve oil cylinder 12 is also lost. As a result, the force holding the valve body 11 in the open state is lost, and the valve element 11a seats on the valve seat 11b. This series of actions occurs in an extremely short time. In other words, the steam valve 10 suddenly closes, and the working steam to the steam turbine is shut off.

[0028] As described above, when an emergency trip signal is generated from the turbine protection circuit, the flow path in the emergency trip device 100 is switched, causing the steam valve 10 to suddenly close.

[0029] FIG. 2 is a system diagram showing the configuration of the emergency trip device 100 according to the first embodiment.

[0030] The emergency trip device 100 is configured to ensure the hydraulic pressure of the emergency oil supplied from the oil supply source to the steam valve 10, and to allow the hydraulic pressure of the emergency oil to be lost when an emergency trip signal is issued.

[0031] The emergency trip device 100 has an emergency oil piping 110, a pilot piping 120, an oil drain piping 130, a connection piping 140, an upstream switching valve 110x, a downstream switching valve 130x, a trip solenoid valve 120a, and a shutoff valve 161 and a supply stop solenoid valve 164 as an emergency oil supply stop unit 160. The shutoff valve 161 functions as a stop valve. The shutoff valve 161 and the supply stop solenoid valve 164 are not limited to those described below, and may be other valves as long as they have similar functions.

[0032] The pilot pipe 120 is a general term for a first pilot pipe 121, a second pilot pipe 122, and a third pilot pipe 123. The trip solenoid valve 120a is a general term for a first trip solenoid valve 121a, a second trip solenoid valve 122a, and a third trip solenoid valve 123a.

[0033] The upstream-side switching valve 110x is a general term for a first upstream-side switching valve 111, a second upstream-side switching valve 112, and a third upstream-side switching valve 113. The downstream-side switching valve 130x is a general term for a first downstream-side switching valve 131, a second downstream-side switching valve 132, and a third downstream-side switching valve 133.

[0034] The connection pipe 140 includes a first connection pipe 141, a second connection pipe 142, and a third connection pipe 143, and is a general term for these.

[0035] The emergency oil piping 110 has an upstream emergency oil piping 110u connected to the oil supply source upstream of the emergency oil supply stop unit 160, and a downstream emergency oil piping 110v connected downstream of the emergency oil supply stop unit 160. The emergency oil piping 110 and the emergency oil supply stop unit 160 form a path for emergency oil from the oil supply source to the steam valve 10. Here, the oil supply source is, for example, a high-pressure oil tank and an oil supply pump, not shown.

[0036] The emergency oil branch pipe 110s branches off from the upstream emergency oil pipe 110u at an emergency oil pipe branch point 110p. The emergency oil branch pipe 110s receives emergency oil from a fuel supply source and supplies it to a trip solenoid valve 120a. The downstream emergency oil pipe 110v is provided with a check valve 110c to prevent backflow, and the emergency oil branch pipe 110s is provided with a check valve 110d to prevent backflow. The trip solenoid valve 120a has the same configuration as the supply stop solenoid valve 164, which will be described later with reference to Figures 3 and 4.

[0037] The oil drain pipe 130 drains emergency oil from the emergency trip device 100. The oil is discharged to, for example, a high-pressure oil tank (not shown). The oil drain pipe 130 has a first oil drain pipe 130a and a second oil drain pipe 130b that join at a joining point 130p. A relief valve 18 is provided between the emergency oil branch pipe 110s and the second oil drain pipe 130b to prevent an abnormal pressure rise in the emergency oil line.

[0038] Each of the upstream switching valves 110x, i.e., the first upstream switching valve 111, the second upstream switching valve 112, and the third upstream switching valve 113, has an A port and a B port connected to the outside and is configured to be able to switch the flow path internally. Each A port is connected to the emergency oil pipe 110, specifically the downstream emergency oil pipe 110v. The upstream switching valves 110x are valves having a configuration similar to that of the shutoff valve 161, which will be described later with reference to FIG. 5.

[0039] Each of the downstream-side switching valves 130x, i.e., the first downstream-side switching valve 131, the second downstream-side switching valve 132, and the third downstream-side switching valve 133, also has an A port and a B port, and is configured to be able to switch the flow path internally. The A port of each is connected to the first oil drain pipe 130a. The downstream-side switching valves 130x have the same configuration as the shutoff valve 161, which will be described later with reference to FIG. 5.

[0040] The primary side of each of the trip solenoid valves 120a, i.e., the first trip solenoid valve 121a, the second trip solenoid valve 122a, and the third trip solenoid valve 123a, is connected to the emergency oil branch pipe 110s, as described above. The trip solenoid valve 120a operates to switch the connection of its secondary side depending on whether or not an emergency trip signal is received from the turbine protection circuit 5. During normal turbine operation, i.e., when no emergency trip signal is received, the secondary side of the trip solenoid valve 120a is connected to each of the pilot pipes 120 indicated by 121, 122, and 123. On the other hand, when an emergency trip signal is received, the trip solenoid valve 120a is internally switched in response to the emergency trip signal, and the secondary side is connected to the oil drain pipe 130, isolating the pilot pipe 120 from the emergency oil branch pipe 110s.

[0041] The connections between the trip solenoid valve 120a and the upstream switching valve 110x and downstream switching valve 130x via the pilot pipe 120 are as follows:

[0042] That is, the first trip solenoid valve 121a is connected to the first upstream switching valve 111 and the first downstream switching valve 131 via a first pilot pipe 121. The second trip solenoid valve 122a is connected to the second upstream switching valve 112 and the second downstream switching valve 132 via a second pilot pipe 122. The third trip solenoid valve 123a is connected to the third upstream switching valve 113 and the third downstream switching valve 133 via a third pilot pipe 123.

[0043] The connection pipes 140, i.e., the first connection pipe 141, the second connection pipe 142, and the third connection pipe 143, respectively connect the B port of the upstream switching valve 110x and the B port of the downstream switching valve 130x. The connection between the upstream switching valve 110x and the downstream switching valve 130x by the connection pipes 140 is a combination that corresponds to emergency trip logic. Specifically, it is as follows.

[0044] The first connecting pipe 141 connects the B port of the second upstream switching valve 112 to the B port of the first downstream switching valve 131. The second connecting pipe 142 connects the B port of the third upstream switching valve 113 to the B port of the second downstream switching valve 132. The third connecting pipe 143 connects the B port of the first upstream switching valve 111 to the B port of the third downstream switching valve 133.

[0045] As described above, the connection between the trip solenoid valve 120a and the upstream-side switching valve 110x and the downstream-side switching valve 130x is, for example, such that the first trip solenoid valve 121a is connected to the first upstream-side switching valve 111 and the first downstream-side switching valve 131. On the other hand, the connection between the upstream-side switching valve 110x and the downstream-side switching valve 130x by the connecting pipe 140 is, for example, such that the second upstream-side switching valve 112 and the first downstream-side switching valve 131 are connected by the first connecting pipe 141.

[0046] In this way, the combination of connections between the trip solenoid valve 120a and the upstream-side switching valve 110x and the downstream-side switching valve 130x is different from the combination of connections between the upstream-side switching valve 110x and the downstream-side switching valve 130x via the connection pipe 140. By changing the combination of the two in this way, a "2 out of 3" logical function can be achieved. In other words, even if one of the upstream-side switching valves 110x and one of the downstream-side switching valves 130x transitions to the open state, the emergency oil pipe 110 on the oil supply source side (downstream emergency oil pipe 110v) and the oil discharge pipe 130 on the discharge side (first oil discharge pipe 130a) will not be connected to each other. On the other hand, if two of the upstream switching valves 110x and two of the downstream switching valves 130x transition to the open state, a communication path is established between the emergency oil piping 110 on the oil supply source side and the oil discharge piping 130 on the discharge side, resulting in a loss of emergency oil pressure to the steam valve 10, and the steam valve 10 will suddenly close.

[0047] In addition to the connecting pipe 140, a line is provided connecting the B port of the upstream switching valve 110x and the B port of the downstream switching valve 130x. Specifically, a line having a check valve 151a and a flow rate adjustment valve 151b is provided between the first upstream switching valve 111 and the first downstream switching valve 131. A line having a check valve 152a and a flow rate adjustment valve 152b is provided between the second upstream switching valve 112 and the second downstream switching valve 132. Furthermore, a line having a check valve 153a and a flow rate adjustment valve 153b is provided between the third upstream switching valve 113 and the third downstream switching valve 133.

[0048] These lines are intended for final pressure equalization within the emergency trip device 100 when the system is shut down. Therefore, they are hardly affected by the sudden closure of the steam valve 10 during an emergency trip, or by abnormal behavior of the line pressure when the system returns to the reset state after the emergency trip signal is released.

[0049] The emergency oil supply stop unit 160 is provided to cut off the flow path of the emergency oil piping 110 when an emergency trip signal is generated. The emergency oil supply stop unit 160 has a shutoff valve 161 and a supply stop solenoid valve 164. The shutoff valve 161 is provided on the emergency oil piping 110. The shutoff valve 161 is disposed downstream of the emergency oil piping branch 110p on the emergency oil piping 110, that is, on the side farther from the oil supply source than the emergency oil piping branch 110p. The supply stop solenoid valve 164 receives emergency oil from the emergency oil branch pipe 110s, and its secondary side is connected to the supply stop solenoid valve 164 by a switching pipe 160a.

[0050] The pilot pipe 120 and the switching pipe 160a, indicated by 121, 122, and 123, are connected to the EHC as shown in Fig. 2. Here, the EHC stands for an electrohydraulic controller, which is a device that controls the steam valve 10 during normal operation using control oil. The EHC also uses high-pressure oil, similar to the emergency oil, as control oil. The emergency trip device 100 is connected to the EHC via these hydraulic pipes, but detailed description thereof will be omitted as it is not directly related to the function of the emergency trip device 100 in this embodiment.

[0051] <Solenoid valve for stopping supply of emergency oil supply> Fig. 3 is a conceptual explanatory diagram showing the internal connections of the supply stop solenoid valve 164 of the emergency oil supply stop unit 160 of the emergency trip device 100 according to the first embodiment in a non-excited state. Also, Fig. 4 is a conceptual explanatory diagram showing the internal connections of the supply stop solenoid valve 164 in an excited state.

[0052] 3 and 4 show an example of a spool-type switching solenoid valve having a moving part 164p inside a housing 164h as the supply stop solenoid valve 164. In FIG.

[0053] A housing 164h of the supply stop solenoid valve 164 is formed with a first port 164a, a second port 164b, and a third port 164c as connection ports with the outside.

[0054] The first port 164a is connected to the emergency oil branch pipe 110s. The second port 164b is connected to the switching pipe 160a to the shutoff valve 161. The third port 164c is connected to the second oil drain pipe 130b.

[0055] In the supply stop solenoid valve 164, an internal moving part 164p moves longitudinally depending on whether the electromagnetic coil is excited, thereby switching the internal flow path. Specifically, the supply stop solenoid valve 164 is in a non-excited state (Fig. 3) during normal operation, i.e., in the turbine reset state. When the supply stop solenoid valve 164 receives an emergency trip signal from the turbine protection circuit 5, the supply stop solenoid valve 164 becomes excited (Fig. 4).

[0056] In the non-excited state of the supply stop solenoid valve 164 shown in Fig. 3, the internal moving part 164p is pressed leftward in Fig. 3 by spring force. In this state, the inside of the first port 164a connected to the emergency oil branch pipe 110s is closed. The second port 164b connected to the switching pipe 160a to the shutoff valve 161 communicates with the third port 164c connected to the second oil drain pipe 130b. Therefore, emergency oil is not supplied to the shutoff valve 161 from the switching pipe 160a.

[0057] The excited state of the supply stop solenoid valve 164 shown in Fig. 4 is the state when an emergency trip signal is issued from the turbine protection circuit 5. In this case, the internal moving part 164p is pressed to the right in Fig. 3 by the electromagnetic coil. In this state, the first port 164a connected to the emergency oil branch pipe 110s and the second port 164b connected to the switching pipe 160a to the shutoff valve 161 are in a communication state. Therefore, emergency oil is supplied from the switching pipe 160a to the shutoff valve 161.

[0058] <Shut-off valve for emergency oil supply stop section> FIG. 5 is a conceptual explanatory diagram showing the shutoff valve 161 of the emergency oil supply stop unit 160 of the emergency trip device 100 according to the first embodiment.

[0059] The shutoff valve 161 has a disk 161d and a spring 161s inside, and is provided with an A port 161a, a B port 161b, and a switching input port 161c as connection ports to the outside.

[0060] The A port 161a is connected to the upstream emergency oil pipe 110u. The B port 161b is connected to the downstream emergency oil pipe 110v. The switching input port 161c is connected to the switching pipe 160a from the supply stop solenoid valve 164.

[0061] When the disk 161d built into the shutoff valve 161 is in the lower position in FIG. 5, i.e., when the A port 161a is closed, the A port 161a and the B port 161b are blocked from each other. That is, the shutoff valve 161 is in a closed state. When the disk 161d is in the upper position in FIG. 5, i.e., when it is separated from the A port 161a, the A port 161a and the B port 161b are in communication with each other. That is, the shutoff valve 161 is in an open state.

[0062] During normal operation of the turbine, i.e., when no emergency trip signal is generated from the turbine protection circuit 5, the supply stop solenoid valve 164 is in a de-energized state, as described above. Therefore, emergency oil is not supplied from the switching pipe 160a to the shutoff valve 161. When emergency oil is not supplied to the switching input port 161c, the disk 161d is pulled upward by the spring 161s, and the A port 161a and the B port 161b are in communication. In other words, the shutoff valve 161 is in an open state. Therefore, during normal operation of the turbine, the upstream emergency oil pipe 110u and the downstream emergency oil pipe 110v are in communication with each other in the emergency oil pipe 110, and an emergency oil supply path from the oil supply source to the steam valve 10 is secured.

[0063] On the other hand, during normal operation of the turbine, that is, when an emergency trip signal is generated from the turbine protection circuit 5, emergency oil is supplied from the supply stop solenoid valve 164 to the switching input port 161c via the switching piping 160a. The oil pressure applied to the switching input port 161c presses the disk 161d of the shutoff valve 161 downward, closing the A port 161a. That is, the A port 161a and the B port 161b are shut off from each other. That is, the shutoff valve 161 is in a closed state. In this way, when an emergency trip signal is generated, the upstream emergency oil piping 110u and the downstream emergency oil piping 110v in the emergency oil piping 110 are shut off by the shutoff valve 161. As a result, the emergency oil supply path from the oil supply source to the steam valve 10 is shut off.

[0064] <Upstream and downstream switching valves> As described above, the upstream switching valves 110x, i.e., the first upstream switching valve 111, the second upstream switching valve 112, and the third upstream switching valve 113, and the downstream switching valves 130x, i.e., the first downstream switching valve 131, the second downstream switching valve 132, and the third downstream switching valve 133, have a configuration similar to that of the shut-off valve 161 shown in Figure 5.

[0065] The switching input ports (ports corresponding to 161c in FIG. 5) of the upstream switching valve 110x and the downstream switching valve 130x are connected to pilot piping 120 indicated by 121, 122, and 123, which is a path for emergency oil from trip solenoid valve 120a indicated by 121a, 122a, and 123a. Therefore, internal communication between port A and port B is established or cut off depending on whether trip solenoid valve 120a is excited or not.

[0066] <Trip solenoid valves for upstream and downstream switching valves> As described above, the trip solenoid valve 120a for switching the upstream switching valve 110x and the downstream switching valve 130x has a configuration similar to that of the supply stop solenoid valve 164 shown in FIG.

[0067] As described above, the supply stop solenoid valve 164 serving as the emergency oil supply stop unit 160 is in a non-excited state during normal operation. The supply stop solenoid valve 164 is configured to transition to an excited state when an emergency trip signal is issued.

[0068] On the other hand, the trip solenoid valves 120a for the upstream switching valves 110x and downstream switching valves 130x are valves that cause the steam valves 10 to suddenly close, i.e., trip the turbine, and therefore are operated in the opposite manner to the supply stop solenoid valve 164. That is, the trip solenoid valves 120a are set to the energized side during normal operation, and to the de-energized side when an emergency trip signal is generated. This is for the following reasons.

[0069] High reliability is required for the parts related to the operation of the turbine protection system. For this reason, the upstream switching valve 110x and the downstream switching valve 130x are combined based on logic such as 2 out of 3. To ensure the reliability of turbine protection, the trip solenoid valve 120a, which switches between the upstream switching valve 110x and the downstream switching valve 130x, is also designed to trip the turbine even in the event of a loss of power supply for operating the solenoid valve. Specifically, the trip solenoid valve 120a is energized during normal operation and de-energized when an emergency trip signal is generated, so that the trip solenoid valve 120a will also be de-energized in the event of a loss of power supply, thereby tripping the turbine.

[0070] <Explanation of action and effect> <During normal operation> First, we will explain the state during normal turbine operation, i.e., the turbine reset state when no emergency trip signal is present. Since there is no emergency trip signal, the supply stop solenoid valve 164 is in a de-energized state, and as a result, the shutoff valve 161 is in a communicating state. Therefore, there is an emergency oil supply path from the upstream emergency oil pipe 110u to the downstream emergency oil pipe 110v and further to the steam valve 10.

[0071] Furthermore, since there is no emergency trip signal, the trip solenoid valves 120a for switching the upstream switching valve 110x and the downstream switching valve 130x are energized. As a result, in the trip solenoid valves 120a indicated by 121a, 122a, and 123a, the primary side of the emergency oil branch pipe 110s is connected to the secondary side of the pilot pipe 120 indicated by 121, 122, and 123. Therefore, emergency oil pressure is ensured up to the switching input ports of the upstream switching valve 110x and the downstream switching valve 130x. As a result, the A port and the B port are blocked in each of the upstream switching valves 110x indicated by 111, 112, and 113 and the downstream switching valves 130x indicated by 131, 132, and 133. As a result, the upstream switching valve 110x and the downstream switching valve 130x are both closed.

[0072] The upstream switching valve 110x and the downstream switching valve 130x serve as boundaries for ensuring the hydraulic pressure of the emergency oil in the downstream emergency oil pipe 110v. When there is no emergency trip signal, the upstream switching valve 110x and the downstream switching valve 130x are all closed. Also, as described above, there is an emergency oil supply path from the upstream emergency oil pipe 110u to the downstream emergency oil pipe 110v and further to the steam valve 10. Therefore, when there is no emergency trip signal, the hydraulic pressure of the emergency oil to the disc dump valve 13 of the steam valve 10 is ensured, and the open state of the steam valve 10 is stably maintained.

[0073] <When an emergency trip signal occurs> Next, a case where an emergency trip signal is generated will be described.

[0074] In response to the emergency trip signal, the trip solenoid valves 120a, designated by 121a, 122a, and 123a, which are used to switch the upstream switching valve 110x and the downstream switching valve 130x, respectively, are de-energized. As a result, the trip solenoid valve 120a connects the emergency oil branch pipe 110s on the primary side to the second oil drain pipe 130b on the secondary side. This prevents emergency oil from being supplied to the switching input ports of the upstream switching valve 110x and the downstream switching valve 130x. As a result, the A and B ports of the upstream switching valve 110x and the downstream switching valve 130x are connected to each other, and the valves are opened.

[0075] 2, the combination of the upstream switching valve 110x, the downstream switching valve 130x, and the connecting pipe 140 is made according to a two-out-of-three logic. Therefore, at least one of the combinations of the upstream switching valve 110x and the downstream switching valve 130x is opened with high reliability.

[0076] In this way, at least one of the combinations of the upstream-side switching valve 110x and the downstream-side switching valve 130x is in the open state, in other words, the upstream-side switching valve 110x and the downstream-side switching valve 130x in a certain combination are in the open state. This forms a flow path consisting of the downstream-side emergency oil piping 110v, the internal flow path from port A to port B in the upstream-side switching valve 110x, the connection piping 140 connecting port B of the upstream-side switching valve 110x and port B of the downstream-side switching valve 130x, the internal flow path from port B to port A in the downstream-side switching valve 130x, and the first oil drain piping 130a.

[0077] In other words, the downstream emergency oil pipe 110v on the oil supply side and the first oil drain pipe 130a on the oil drain side are connected. As a result, emergency oil is no longer supplied to the disk dump valve 13 of the steam valve 10, and the oil pressure of the emergency oil drops and is lost. The loss of oil pressure to the disk dump valve 13 causes the steam valve 10 to suddenly close.

[0078] Furthermore, when an emergency trip signal is generated, the supply stop solenoid valve 164 transitions to an excited state. As a result, the shutoff valve 161 transitions to a closed state. Therefore, the supply of emergency oil from the upstream emergency oil pipe 110u to the downstream emergency oil pipe 110v is cut off.

[0079] As described above, when an emergency trip signal is generated, the emergency trip device 100 is brought into a state where the downstream emergency oil pipe 110v, which is the oil supply side, is connected to the first oil drain pipe 130a, which is the oil drain side. As a result, the oil pressure of the emergency oil is lost, and the steam valve 10 is suddenly closed. Furthermore, due to the operation of the emergency oil supply stop unit 160, the emergency trip device 100 is not brought into a state where the supply of emergency oil from the upstream emergency oil pipe 110u to the downstream emergency oil pipe 110v continues.

[0080] <When the turbine trip signal is reset> A case where the turbine trip signal is reset to return to a normal operating state from a turbine trip state will be described.

[0081] In the conventional example shown in Fig. 11, even after an emergency trip signal is generated, emergency oil continues to be supplied from the emergency oil pipe 110 to the oil drain pipe 130, and the emergency oil continues to fill the connecting pipe 140. This causes problematic behavior when the turbine trip signal is reset.

[0082] On the other hand, in the emergency trip device 100 according to this embodiment, as described above, when an emergency trip signal is generated, the downstream emergency oil pipe 110v on the oil supply side and the first oil drain pipe 130a on the oil drain side are in a state of communication with each other in the emergency trip device 100. Furthermore, the operation of the emergency oil supply stop unit 160 cuts off the supply of emergency oil from the upstream emergency oil pipe 110u to the downstream emergency oil pipe 110v.

[0083] In this way, after the turbine trip, the portion downstream of the emergency oil supply stop unit 160 in the emergency trip device 100 is not filled with emergency oil, including the connecting pipe 140. As a result, even when the upstream switching valve 110x and the downstream switching valve 130x close when the turbine trip signal is reset, problematic behavior that has conventionally occurred, such as an abnormal rise in oil pressure within the emergency trip device 100, does not occur.

[0084] [Second embodiment] FIG. 6 is a system diagram showing the configuration of an emergency trip device 100a according to the second embodiment.

[0085] This embodiment is a modification of the first embodiment. The emergency oil supply stop unit 160 of the emergency trip device 100a in this embodiment has a pilot check valve 162 instead of the shutoff valve 161 in the first embodiment. That is, the emergency oil supply stop unit 160 of the emergency trip device 100a in this embodiment has the pilot check valve 162 and a supply stop solenoid valve 164. The pilot check valve 162 functions as a stop valve. Furthermore, the pilot check valve 162 is not limited to the one described below, and may be any other valve as long as it has a similar function.

[0086] The difference from the first embodiment is the pilot check valve 162 and the connection between this pilot check valve 162 and the piping, and other than that, it is the same as the first embodiment. Therefore, only the difference from the first embodiment will be described.

[0087] FIG. 7 is a conceptual explanatory diagram showing a pilot check valve 162 of an emergency oil supply stop unit 160 of an emergency trip device 100a according to the second embodiment.

[0088] The pilot check valve 162 has a first port 162a, a second port 162b, and an external pilot port 162c. When no hydraulic pressure is applied from the external pilot port 162c, it functions as a check valve, allowing flow only from the first port 162a to the second port 162b.

[0089] On the other hand, when hydraulic pressure is applied from the external pilot port 162c, the check valve function is lost and a flow from the second port 162b to the first port 162a is also possible, i.e., a flow in both directions is possible.

[0090] In the pilot check valve 162 of this embodiment, the second port 162b is connected to an upstream emergency oil pipe 110u that is upstream of the pilot check valve 162 when viewed from the oil supply source. Also, the first port 162a is connected to a downstream emergency oil pipe 110v that is downstream of the pilot check valve 162 when viewed from the oil supply source. Also, the external pilot port 162c is connected to a switching pipe 160a that extends from the supply stop solenoid valve 164.

[0091] Therefore, during normal operation when no emergency trip signal is issued, the flow from the upstream emergency oil pipe 110u on the upstream side to the downstream emergency oil pipe 110v on the downstream side is in the opposite direction to the one-way flow of the check valve. To enable this reverse flow, oil pressure must be applied to the external pilot port 162c from the supply stop solenoid valve 164 via the switching pipe 160a.

[0092] In this embodiment, the supply cutoff solenoid valve 164 is operated in an excited state during normal turbine operation and in a de-excited state when an emergency trip signal is generated, contrary to the first embodiment.

[0093] During normal operation, the supply stop solenoid valve 164 is in an excited state, so the switching pipe 160a is in communication with the emergency oil branch pipe 110s, and oil pressure is maintained. As a result, oil pressure is applied from the external pilot port 162c, and the pilot check valve 162 is in a state where it can pass in both directions, as shown by the arrows labeled "pressurized" in Figure 6. Therefore, the upstream emergency oil pipe 110u and the downstream emergency oil pipe 110v are in communication, and the emergency oil supply path to the steam valve 10 is maintained.

[0094] On the other hand, when an emergency trip signal is generated, the supply stop solenoid valve 164 is de-energized, and the oil pressure in the switching pipe 160a is lost. As a result, the oil pressure to the external pilot port 162c is lost, and the pilot check valve 162 functions as a check valve, as shown by the arrow "non-pressurized" in Figure 6, and the inflow of emergency oil from the upstream emergency oil pipe 110u to the downstream emergency oil pipe 110v is prevented.

[0095] In other words, the pilot check valve 162 and the supply stop solenoid valve 164 serving as the emergency oil supply stop unit 160 in this embodiment ensure an emergency oil supply path to the steam valve 10 during normal operation, and cut off the emergency oil supply path to the steam valve 10 when an emergency oil trip signal is generated.

[0096] As described above, the emergency oil supply stop unit 160 in this embodiment has the same function as in Embodiment 1. As a result, the emergency trip device 100a in this embodiment has the same actions and effects as in the first embodiment.

[0097] [Third embodiment] FIG. 8 is a system diagram showing the configuration of an emergency trip device 100b according to the third embodiment.

[0098] This embodiment is a modification of the first embodiment. The emergency oil supply stop unit 160 of the emergency trip device 100b in this embodiment has a spool valve 163 instead of the shutoff valve 161 in the first embodiment. That is, the emergency oil supply stop unit 160 of the emergency trip device 100b in this embodiment has the spool valve 163 and a supply stop solenoid valve 164. The spool valve 163 functions as a stop valve. Furthermore, the spool valve 163 is not limited to the one described below, and may be any other valve as long as it has a similar function.

[0099] The difference from the first embodiment is the spool valve 163 and the connection between this spool valve 163 and the piping, and other than that it is the same as the first embodiment. Therefore, only the difference from the first embodiment will be described.

[0100] Fig. 9 is a conceptual explanatory diagram showing a state in which the spool valve 163 of the emergency oil supply stop unit 160 of the emergency trip device 100b according to the third embodiment is in an open state. Fig. 10 is a conceptual explanatory diagram showing a state in which the spool valve 163 is in a closed state.

[0101] A first port 163a, a second port 163b, and an external pilot port 163c are formed as connection ports to the outside in a housing 163h of the spool valve 163. In the spool valve 163, a moving part 163p moves in the longitudinal direction inside the housing 163h, thereby switching the internal flow path.

[0102] In the spool valve 163 of this embodiment, a first port 163a is connected to the upstream emergency oil pipe 110u, a second port 163b is connected to the downstream emergency oil pipe 110v, and an external pilot port 163c is connected to the switching pipe 160a from the supply stop solenoid valve 164.

[0103] Unlike the first embodiment, but similar to the second embodiment, the supply stop solenoid valve 164 is energized during normal turbine operation and de-energized when an emergency trip signal is generated. Therefore, during normal operation, the switching pipe 160a is in communication with the emergency oil branch pipe 110s, ensuring oil pressure.

[0104] During normal operation, the supply stop solenoid valve 164 is in an excited state, so the switching pipe 160a is in communication with the emergency oil branch pipe 110s, and hydraulic pressure is maintained. That is, hydraulic pressure is applied to the external pilot port 163c of the spool valve 163. In this case, the hydraulic pressure overcomes the spring force, and the moving part 163p is pressed to the right side of the figure within the housing 163h, as shown in FIG. 9. In this state, the first port 163a and the second port 163b are in communication. As a result, during normal operation, the upstream emergency oil pipe 110u and the downstream emergency oil pipe 110v are in communication, and the emergency oil supply path to the steam valve 10 is maintained.

[0105] On the other hand, when an emergency trip signal is generated, the supply stop solenoid valve 164 is de-energized, and hydraulic pressure is lost in the switching pipe 160a. As a result, hydraulic pressure to the external pilot port 163c of the spool valve 163 is lost. Furthermore, as shown in FIG. 10, the spring force causes the moving part 163p to be pressed to the left side in the drawing within the housing 163h. In this state, the first port 163a and the second port 163b are blocked from each other. As a result, when an emergency trip signal is generated, the spool valve 163 blocks communication between the upstream emergency oil pipe 110u and the downstream emergency oil pipe 110v.

[0106] In other words, the spool valve 163 and the supply stop solenoid valve 164 serving as the emergency oil supply stop unit 160 in this embodiment ensure an emergency oil supply path to the steam valve 10 during normal operation, and cut off the emergency oil supply path to the steam valve 10 when an emergency oil trip signal is generated.

[0107] As described above, the emergency oil supply stop unit 160 in this embodiment has the same function as in Embodiment 1. As a result, the emergency trip device 100a in this embodiment has the same actions and effects as in the first embodiment.

[0108] According to the embodiment described above, it is possible to provide an emergency trip device for a steam turbine that does not cause hunting when the turbine recovers from a tripped state.

[0109] [Other embodiments] Although the embodiments of the present invention have been described above, they are presented as examples and are not intended to limit the scope of the invention. Furthermore, features of each embodiment may be combined. Furthermore, the embodiments may be implemented in various other forms, and various omissions, substitutions, and modifications may be made without departing from the spirit of the invention. The embodiments and their modifications are intended to be included within the scope and spirit of the invention, as well as within the scope of the invention and its equivalents as set forth in the claims. [Explanation of symbols]

[0110] 5...turbine protection circuit, 10...steam valve, 11...valve body, 11a...valve disc, 11b...valve seat, 12...valve oil cylinder, 13...disk dump valve, 15a, 15b...test solenoid valve, 18...relief valve, 100, 100a, 100b...emergency trip device, 110...emergency oil piping, 110c, 110d...check valve, 110u...upstream emergency oil piping, 110v...downstream emergency oil piping, 110p...emergency oil piping branch, 110s...emergency oil branch pipe, 110x...upstream switching valve, 111...first Upstream switching valve, 112...second upstream switching valve, 113...third upstream switching valve, 120...pilot piping, 120a...trip solenoid valve, 121...first pilot piping, 121a...first trip solenoid valve, 122...second pilot piping, 122a...second trip solenoid valve, 123...third pilot piping, 123a...third trip solenoid valve, 130...oil drain piping, 130a...first oil drain piping, 130b...second oil drain piping, 130p...junction, 130x...downstream switching valve, 1 31...first downstream switching valve, 132...second downstream switching valve, 133...third downstream switching valve, 140...connecting pipe, 141...first connecting pipe, 142...second connecting pipe, 143...third connecting pipe, 151a...check valve, 151b...flow rate adjustment valve, 152a...check valve, 152b...flow rate adjustment valve, 153a...check valve, 153b...flow rate adjustment valve, 160...emergency oil supply stop unit, 160a...switching pipe, 161...shutoff valve, 161a...A port, 161b...B port, 161c...switching Input port, 161a...disc, 161b...spring, 162...pilot check valve, 162a...first port, 162b...second port, 162c...external pilot port, 163...spool valve, 163a...first port, 163b...second port, 163c...external pilot port, 163h...casing, 163p...moving part, 164...supply stop solenoid valve, 164a...first port, 164b...second port, 164c...third port, 164h...casing, 164p...moving part

Claims

1. 1. An emergency trip device for a steam turbine, which receives an emergency trip signal to cause a loss of hydraulic pressure of emergency oil supplied to a steam valve, and which maintains hydraulic pressure of the emergency oil before the emergency trip signal is generated, an emergency oil pipe connected to a fuel supply source and serving as a path for the emergency oil from the fuel supply source to the steam valve; a plurality of upstream switching valves, each having an upstream switching valve A port and an upstream switching valve B port, the upstream switching valve A port being connected to the emergency oil piping; an oil drain pipe for draining the emergency oil; a plurality of downstream switching valves each having a downstream switching valve A port and a downstream switching valve B port, the downstream switching valve A port being connected to the oil drain pipe; a plurality of connection pipes connecting the upstream switching valve B ports of the plurality of upstream switching valves to the downstream switching valve B ports of the plurality of downstream switching valves; the upstream side is supplied with the emergency oil from the emergency oil piping, and the downstream side is a plurality of trip solenoid valves that can be switched between a connection state with the plurality of upstream switching valves and a connection state with the oil drain piping; an emergency oil supply stop unit capable of blocking a flow path of the emergency oil piping; An emergency trip device for a steam turbine, comprising:

2. The emergency oil supply stop unit is a supply cutoff solenoid valve that operates in response to the emergency trip signal; a stop valve that is provided in the emergency oil piping, divides the emergency oil piping into an upstream emergency oil piping and a downstream emergency oil piping, and closes in response to operation of the supply stop electromagnetic valve to stop the supply of the emergency oil to the plurality of upstream switching valves; 2. The emergency trip device for a steam turbine according to claim 1, further comprising:

3. 3. The emergency trip device for a steam turbine according to claim 2, wherein the stop valve is one of a shutoff valve, a pilot check valve, and a spool valve.

4. The shut-off valve is a shutoff valve A port connected to the upstream emergency oil piping; a shutoff valve B port connected to the downstream emergency oil piping; a switching input port for switching between a communication state and a cut-off state between the cut-off valve A port and the cut-off valve B port in the cut-off valve; 4. The emergency trip device for a steam turbine according to claim 3, further comprising:

5. The pilot check valve is a pilot check valve A port connected to the upstream emergency oil piping; a pilot check valve B port connected to the downstream emergency oil piping; an external pilot port for switching the pilot check valve between a one-way state as a check valve and a state allowing passage in both directions; 4. The emergency trip device for a steam turbine according to claim 3, further comprising:

6. The spool valve is a first port connected to the upstream emergency oil pipe; a second port connected to the downstream emergency oil piping; a third port for switching between a communication state and a cutoff state between the first port and the second port by moving a moving portion within the spool valve; 4. The emergency trip device for a steam turbine according to claim 3, further comprising:

7. The emergency oil piping has an emergency oil branch pipe that branches off from an emergency oil piping branch portion and supplies the emergency oil to the plurality of trip solenoid valves, 7. The steam turbine emergency trip device according to claim 1, wherein the position at which the emergency oil supply stop unit blocks the flow path of the emergency oil piping is a portion of the emergency oil piping downstream of the emergency oil piping branching section from which the emergency oil branch pipe branches.

8. the plurality of upstream switching valves include a first upstream switching valve, a second upstream switching valve, and a third upstream switching valve; the plurality of downstream switching valves include a first downstream switching valve, a second downstream switching valve, and a third downstream switching valve; The plurality of connecting pipes include: a first connection pipe connecting the upstream switching valve B port of the first upstream switching valve and the downstream switching valve B port of the first downstream switching valve; a second connection pipe connecting the upstream switching valve B port of the second upstream switching valve and the downstream switching valve B port of the second downstream switching valve; a third connection pipe connecting the upstream switching valve B port of the third upstream switching valve and the downstream switching valve B port of the third downstream switching valve; and The plurality of trip solenoid valves include: a first trip solenoid valve that receives the emergency trip signal and switches the third upstream switching valve and the first downstream switching valve; a second trip solenoid valve that receives the emergency trip signal and switches the first upstream switching valve and the second downstream switching valve; a third trip solenoid valve that receives the emergency trip signal and switches the second upstream switching valve and the third downstream switching valve; having 2. The emergency trip device for a steam turbine according to claim 1.

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