JPH10131710A - Steam turbine controlling device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To surely prevent the malfunction of a main steam stop valve by providing a switch valve on the outlet side of an electric/hydraulic converter and switching oil supply by means of a switch valve after finishing the whole periphery jet running of the main steam stop valve in a device which supplies pressure oil from the electric/hydraulic converter to the oil cylinder of the main steam stop valve through a valve test device. SOLUTION: The starting device 61 of a control section 60, when started, outputs a valve opening signal to an electric/hydraulic converter 66 to let a main steam stop valve 50 perform whole periphery jet running, supplying control oil to a switch valve 70. Then, the control oil is supplied to an oil cylinder 58 through the test drive valve 73 of a valve test device 69 to press a piston 57 resulting in the opening of a main valve 54 and an auxiliary valve 55. After that, when a steam turbine starts rated load running after the finish of whole periphery jet running, the supply of the control oil of the electric/hydraulic converter 66 is cut off, the control oil is supplied through a bypass pipe 68. In this condition, since even if the starting device 61 or electric/hydraulic converter 66 is damaged, a main valve and auxiliary valve 55 can be maintained opened, preventing a turbine shaft from running away.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a steam turbine control device, and more particularly to a steam turbine control device capable of reliably opening and closing a main steam stop valve even when an unexpected situation occurs in an electric command system.

[0002]

2. Description of the Related Art Conventionally, in a power plant such as a thermal power plant or a nuclear power plant, stable power can be supplied by steam guided from a steam generator to a steam turbine. In the event that a steam is generated, many super-large steam valves are provided so that the steam can be quickly cut off, and one of them is a main steam stop valve.

[0003] The main steam stop valve quickly shuts off steam and prevents runaway of the steam turbine when the power transmission line system is short-circuited due to, for example, a lightning strike during steam turbine startup operation or steam turbine operation during steam turbine start-up operation. It is an indispensable valve that plays an important role in power plants such as emergency stop operation.

A power plant having such an important and indispensable main steam stop valve has a Rankine cycle for generating power by circulating steam as shown in FIG.

The steam generator 1 generates steam and supplies the steam to the high-pressure turbine 5 through the main steam pipe 2.

[0006] A main steam stop valve 3 is provided on the inlet side of the high pressure turbine 5, and the supply and stop of steam to the high pressure turbine 5 are performed by opening and closing the main steam stop valve 3.
A steam control valve 4 is provided on the downstream side of the main steam stop valve 3, and the steam control valve 4 opens and closes to control the steam flow rate so as to meet the power demand increase / decrease request.

Further, the main steam stop valve 3,
The steam supplied through the steam control valve 4 performs expansion work in the high-pressure turbine 5, gives a rotational torque to the turbine shaft 6, and returns to the reheater 8 through the low-temperature reheat pipe 7 as exhaust steam. As a reheat steam, a medium pressure turbine 12 is passed through a high temperature reheat pipe 9 having a reheat steam stop valve 10 and an intercept valve 11.
Supplied to

After being expanded, the reheated steam supplied to the intermediate-pressure turbine 12 is supplied to low-pressure turbines 14, 14 of a counter-flow type via a crossover pipe 13, respectively. After driving 16, it is guided to the condenser 15, where it is condensed and returned to the steam generator 1 as condensed water and water supply.

Incidentally, the governing stage of the steam turbine is divided into several nozzle blocks, and when the steam turbine is started, an ultra-high pressure and an ultra-high temperature generated in the steam generator 1, for example, 250 kg / cm ² , When the steam of 538 ° C. is partially supplied to the high-pressure turbine 5, an abnormally high thermal stress is generated in the metal in that stage, which causes cracks or breakage. Therefore, the main steam stop valve 3 is housed therein. Of the main valve and the sub-valve, the sub-valve is first opened to supply steam to the high-pressure turbine 5, that is, a so-called full-circle injection operation is performed.

In the full-circle injection operation, for example, all valve bodies of the steam control valve 4 having four valve bodies are opened in advance,
Supplying steam from the main steam stop valve 3 to the high-pressure turbine 5;
At the beginning of the operation, the sub-valve of the main steam stop valve 3 is maintained in a fully opened state, and the steam is uniformly flowed to all the nozzles of the steam turbine governing stage. The temperature of the high-pressure turbine 5 is evenly increased. This operation is performed up to 7 to 10% of the rated load,
Thereafter, the pressure in the chest of the steam control valve 4 (the lead pipe connecting the main steam stop valve to the steam control valve) is increased, the throttle is once opened, and the main steam stop valve 3 is opened. It has been migrated.

The main steam stop valve 3 controls the flow rate of steam during the above-described full-circle injection operation. In addition, the steam high-pressure turbine 5 A control device is provided for stopping supply to the turbine shaft and preventing runaway of the turbine shaft 6, and its configuration is shown in FIG.

The main steam stop valve 3 accommodates a main valve 20 and a sub-valve 21 as a valve body in a valve casing 17 having a steam inlet 18 and a steam outlet 19, and moves the main valve 20 and the sub-valve 21 forward and backward. The piston 2 is connected to a rod 22 and is supplied and discharged with pressure oil controlled to a predetermined pressure by a booster (not shown).
3 and a disk dump valve 25 for quickly discharging pressure oil to the bottom of the oil cylinder 24.
, Respectively.

Further, the pressure oil in the oil cylinder 24 is supplied and exhausted to
A control unit 26 for moving the sub-valve 21 forward and backward includes a floating lever 29 connected to a full-circle injection mechanism 27 via a rod (link mechanism) 28, and the displacement of the floating lever 29 causes the pressure from the valve test device 31 to be increased. Each of the pilot valves 30 supplies oil to the bottom of the oil cylinder 24.

On the other hand, the motor 3
The piston valve 34 which moves forward and backward by the rotation force of 2 or by the manual force of the handle 33, an unexpected situation occurs during operation, and the supply of emergency oil from an emergency device (not shown) is cut off by a trip signal. At this time, a trip valve 35 for releasing the latch 39 and returning the rod 28 to the starting point is provided. After the trip, the all-around injection mechanism 27
The motor 32 is driven to rotate, and the latch 39 is engaged with the rod 28 again.

The pilot valve 30 includes a valve test device 31 for closing the main valve 20 and the sub-valve 21 during operation in order to confirm whether or not the stick of the valve rod 22 of the main steam stop valve 3 is present. Is provided. This valve test device 31
The air-operated valve 36 and the test drive valve 37 are combined, and the piston valve 40 of the air-operated valve 36 moves forward and backward by the driving force of the solenoid valve 38, guides the air to the test drive valve 37, and presses the piston valve 41. Then, the control oil supplied from the hydraulic pressure generator (not shown) to the oil cylinder 24 via the test drive valve 37 and the pilot valve 30 is cut off, and the main valve 20 and the sub-valve 21 are operated for one day by the elastic force of the spring 42. The valve is closed during one operation.

The main steam stop valve 3 having such a control section 26 rotates the motor 32 of the full-circle injection mechanism 27 by a valve opening command of a starter (not shown) during a start-up operation. Is displaced to the position indicated by the one-dot chain line, and the floating lever 29 is displaced in accordance with the displacement, and the control oil is transmitted from the test drive valve 37 to the oil cylinder 24 via the pilot valve 30 through the opening of the port 43 of the pilot valve 30. And presses the piston 23 to open the sub-valve 21 and the main valve 20.

On the other hand, if a trip command is issued from the turbine protection device during operation of the steam turbine for some reason, the supply of emergency oil to the emergency device (not shown) is cut off, and the latch 39 is released from the rod 28. The oil is removed to disable the operating force from the full circumference injection mechanism 27 to the rod 28, and the supply of emergency oil to the disk dump valve 25 of the oil cylinder 24 is also cut off. For this reason, the disc dump valve 25 is opened apart from the position shown in the figure, and the pressure oil pressing the piston 23 is returned from the port 44 to a hydraulic pressure generator (not shown). Was rapidly closed.

[0018]

The conventional control unit 26 comprises:
When the main valve 20 and the sub-valve 21 of the main steam stop valve 3 are opened and closed, a mechanical transmission force such as a link mechanism or a floating lever is used. There is a lot of galling and the like, and it is necessary to always maintain the mechanical parts so that there is no delay in the transmission force at the time of opening and closing the valve, which is one of the burdens on the workers.

For this reason, in recent years, in addition to the mechanical type, the electro-hydraulic type having a quick response has been adopted.

As shown in FIG. 11, this electro-hydraulic type converts an electric signal into a driving force of pressurized oil instead of a mechanical position signal of the control unit 26, and the main valve 20 of the main steam stop valve 3, The sub-valve 21 is opened and closed.

That is, during the start-up operation, when a valve opening command is issued from the valve position controller 46 of the starter 45, the electro-hydraulic converter 47
Excites the coil, displaces the nozzle to a predetermined position, moves the land of the spool valve 48, and supplies control oil to the oil cylinder 24 via the test drive valve 37 of the valve test device 31,
The main valve 20 and the sub-valve 21 are opened by pressing the piston 23. In this case, the stroke of the piston 23 is converted into an electric signal by a valve position detector (differential transformer) 49, and the stroke signal a is fed back to the valve position control unit 46 to obtain the desired valve position by the activation device 45. It is designed to be performed.

During operation, when a trip command is input to the valve position controller 46 of the starter 45, the electro-hydraulic converter 47
Changes the position of the nozzle, moves the land of the spool valve 48 to another position, cuts off the supply of control oil to the oil cylinder 24, and at the same time the supply of emergency oil disappears due to a trip command. Is opened, the pressure oil pressing the piston 23 is returned to the hydraulic supply device, and the main valve 20 and the sub-valve 21 are rapidly closed.

The conventional electro-hydraulic control device shown in FIG. 11 has a quick response of the transmission force due to a small number of mechanical connection parts, and can perform accurate valve position control. Therefore, it has some problems.

First, the valve opening / closing signal must always be applied to the electro-hydraulic converter 47 from the starting device 45 even during normal operation. As described above, the main steam stop valve 3 is
Only during the start-up operation, the valve position is controlled to control the flow rate of steam during the full-circle injection operation. When the full-circle injection operation ends, the valve remains fully open.

However, when the starting device 45 or the valve position control unit 46 fails, for example, when the power supply is cut off or the signal is abnormal, the signal applied to the electro-hydraulic converter 47 is cut off or reduced, and the main steam stop is stopped. As a result, the valve 3 is closed, and steam cannot be supplied to the steam turbine despite the absence of the trip command.

In order to prevent such an electrical accident,
Conventionally, the activating device 45 has a multiplexed power source, a multiplexed valve position control unit 46, and a two-out-of-three (protection function that operates on the condition that two of the three signals are present).
And so on, to improve the reliability of the control circuit. However, the cost is high due to the heavy equipment.

Second, while the control oil is being supplied from the spool valve 48 to the oil cylinder 24, an electrical failure of the electro-hydraulic converter 47 occurs. With this, the emergency device also operates for some reason. When the device is reset (returned), since the spool valve 48 is in the port open state, the control oil is supplied to the oil cylinder 24 despite the fact that the valve opening command is not issued from the activation device 45 to the main steam stop valve 3. May flow to open the main steam stop valve 3. In this case, the steam flows into the steam turbine abruptly, rapidly increasing the rotation speed, causing the turbine shaft 6 to run away, and is exposed to a dangerous state.

The present invention has been made in view of such circumstances, and it is possible to reliably prevent a malfunction of a main steam stop valve even if an electrical accident occurs, and to operate the main steam stop valve at low cost. It is an object to provide a steam turbine control device that can be opened and closed.

[0029]

According to a first aspect of the present invention, there is provided a steam turbine control device comprising a main steam stop valve, a valve test device, and an electro-hydraulic converter. When a valve opening command is issued from the starting device to the main steam stop valve, the steam turbine control device supplies pressure oil to the oil cylinder of the main steam stop valve from the electro-oil converter via the valve test device. A switching valve on the outlet side of the electro-oil converter, and an electromagnetic valve for switching by driving a piston valve of the switching valve after the peripheral injection operation of the main steam stop valve is completed.

According to a second aspect of the present invention, there is provided a steam turbine control device according to the present invention, wherein the switching valve includes a pressure oil system for directly supplying pressure oil from an electro-hydraulic converter. And bypass pipes for supplying pressure oil by bypassing the electric oil converter.

In order to achieve the above object, in the steam turbine control device according to the present invention, as described in claim 3, the switching valve is connected to the main oil stop valve from the electro-hydraulic converter during the full-circle injection operation. While the pressurized oil is supplied to the oil cylinder of the main steam stop valve, the pressurized oil from the bypass pipe is supplied to the oil cylinder of the main steam stop valve after the full circumference injection operation of the main steam stop valve is completed.

In order to achieve the above object, in the steam turbine control device according to the present invention, the switching valve is connected to the electro-hydraulic converter after the end of the full circumference injection operation of the main steam stop valve. And a port for pressing the piston valve with another pressure oil so that the pressure oil from the bypass pipe can be supplied to the oil cylinder of the main steam stop valve.

According to a fifth aspect of the present invention, there is provided a steam turbine control device according to the present invention, wherein the solenoid valve includes one of a valve test device and an oil cylinder of a main steam stop valve. It is provided with a pressure oil pipe that presses a piston valve with pressure oil supplied from one side and closes a port.

In order to achieve the above object, a steam turbine control device according to the present invention combines a main steam stop valve with a valve test device and an electro-hydraulic converter, and starts the main steam stop valve from the starting device. When a valve closing command is issued to the steam stop valve, in the steam turbine control device for supplying pressure oil to the oil cylinder of the main steam stop valve from the electro-oil converter via a valve test device, the electro-oil converter Is provided with an interlock valve on the outlet side.

In order to achieve the above object, the steam turbine control device according to the present invention, as described in claim 7, closes a port on the interlock valve by pressing a piston valve, and switches the interlock valve from the electro-hydraulic converter. It is provided with a pressure oil branch pipe for cutting off the pressure oil supplied to the oil cylinder of the main steam stop valve.

In order to achieve the above object, in the steam turbine control device according to the present invention, the pressure oil branch pipe is provided with a pressure connecting the interlock valve and the spool valve of the electric oil converter. It is bypassed from the oil pipe and connected to another port of the interlock valve.

[0037]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of a steam turbine control device according to the present invention will be described below with reference to the drawings.

FIG. 1 is a schematic control system diagram in which steam according to the present invention is applied to a main steam stop valve.

The main steam stop valve 50 includes a valve casing 53 having a steam inlet 51 and a steam outlet 52, in which a main valve 54 and an auxiliary valve 55 are accommodated, and a valve rod 5 for moving the main valve 54 and the auxiliary valve 55 forward and backward.
6 and an oil cylinder 58 that slides a piston 57 by supplying and discharging pressure oil. The main steam stop valve 50 is provided with a disk dump valve 59 at the bottom of the oil cylinder 58, electrically detects the stroke of the valve rod 56, and outputs a detection signal a to the valve position control incorporated in the control unit 60. A valve position detector 63 that feeds back to the section 62 is provided.

On the other hand, the control unit 60 includes a starting device 61 as a control logic circuit in a control panel of a control room.
The valve position control unit 62 is sequentially incorporated to instruct the main valve 54 and the sub-valve 55 of the main steam stop valve 50 to open and close the valve, and to constantly monitor the valve opening position.

The control unit 60 moves the piston valve 65 forward and backward by the driving force of the solenoid valve 64, and is supplied with control oil from the spool valve 67 of the electro-hydraulic converter 66 or from the bypass pipe 68. A switching valve 70 that presses the piston 57 of the oil cylinder 58 via 69 to open the main valve 54 and the sub-valve 55 is provided.

A valve test device 69 connected to the switching valve 70 is a combination of an air-operated valve 71 and a test drive valve 72. The drive force of the air-operated valve 71 causes the piston valve 73 of the test drive valve 72 to operate. The main valve 54 and the sub-valve 55 are moved once a day to stop the supply of control oil to the oil cylinder 58.
Is closed, and at this time, the presence or absence of the stick of the valve rod 56 is confirmed.

Next, the operation will be described.

During the start-up operation, the starter 61 of the controller 60
Is to make the main steam stop valve 50 perform the full-circle injection operation.
A valve opening command signal is output to the electro-oil converter 66. Based on this command, the electro-oil converter 66 excites a coil (not shown), moves the nozzle 74 to a predetermined port position of the spool valve 67, and supplies control oil to the switching valve 70. At that time, the solenoid valve 64 is demagnetized, and only the port 75 of the switching valve 70 is opened.

The switching valve 70 supplies control oil to the oil cylinder 58 via the test drive valve 73 of the valve test device 69, and presses the piston 57 to open the main valve 54 and the sub-valve 55.

When the main valve 54 and the sub-valve 55 are opened in this way, the steam is preliminarily opened from the steam inlet 51 of the main steam stop valve 50 via the steam outlet 52 to a steam control valve (not shown) of all the valve openings. To perform a full-circle injection operation corresponding to warming inside the steam turbine.

When the full-circle injection operation is completed and the steam turbine enters the rated load operation, the solenoid valve 64 excites the coil and switches the control valve 7 while reducing the pressure of the control oil through the orifice 76.
0, press the piston valve 65, close the port 78, open the port 75, and
The supply of the control oil is stopped so that the control oil is always supplied from the bypass pipe 68.

As described above, in this embodiment, during the rated load operation of the steam turbine, the bypass pipe 68 and the switching valve 70 are operated.
Control oil can always be supplied to the oil cylinder 58 through the main valve 5 so that the main valve 5 of the main steam stop valve 50 can be operated even if the power supply of the starting device 61 or the electro-hydraulic converter 66 is cut off or an electric failure occurs.
4. The opening of the sub-valve 55 can always be maintained, and even if an unexpected situation occurs due to an electrical failure, the turbine shaft does not run away and safe operation can be performed.

FIG. 2 is a control system diagram schematically showing a first example of the first embodiment of the steam turbine control device according to the present invention. The same parts as those of the first embodiment are denoted by the same reference numerals.

In this embodiment, after the piston valve 65 of the switching valve 70 is moved by the driving force of the solenoid valve 64, the position of the piston valve 65 is maintained even if there is an electrical failure in the solenoid valve 64 for some reason. The switching valve 70 is provided with an emergency oil supply port 79 so as to be able to do so.

When the full-circumferential injection operation of the main steam stop valve 50 is completed, the solenoid valve 64, as shown in FIG.
, The piston valve 64b is moved from the position shown in the figure, control oil is supplied to the switching valve 70 via the orifice 76, the piston valve 65 is pressed, the port 78 is closed, the port 75 is opened, and the bypass is opened. The control oil from the pipe 68 is supplied to the oil cylinder 58 of the main steam stop valve 50 through the port 75
The main valve 54 and the sub-valve 55 are kept open, but during operation, if a sudden electrical failure such as a power loss occurs in the solenoid valve 64 and the electro-hydraulic converter 66, the piston valve 6
5 is returned to the illustrated position, and the main valve 54 and the sub-valve 55
Cannot be maintained, and the supply of steam to the steam turbine is cut off even though the trip command has not been input to the activation device 61.

For this reason, in this embodiment, as shown in FIG. 4, after the position of the piston valve 65 of the switching valve 70 is moved by the driving force of the solenoid valve 64, an electrical failure occurs in the solenoid valve 64. Also, by merely supplying emergency oil to the emergency oil supply port 79, the piston valve 65 is maintained at the illustrated position, and control oil from the bypass pipe 68 is supplied to the port 75,
By supplying the oil to the oil cylinder 58 via the test drive valve 72, the main valve 54 and the sub-valve 55 can always be kept open except for the turbine trip.

Therefore, according to the present embodiment, the switching valve 70 is provided with a so-called self-holding function, and the main steam stop valve 50 is not closed except for a turbine trip. Even so, the steam turbine can be continuously operated stably.

FIG. 5 is a control system diagram schematically showing a second example of the first embodiment of the steam turbine control device according to the present invention. The same parts as those of the first embodiment are denoted by the same reference numerals.

In this embodiment, a pressure oil pipe 80 is provided so that a part of the pressure oil supplied from the test drive valve 72 to the oil cylinder 58 of the main steam stop valve 50 can also be supplied to the solenoid valve 64.
4, the switching valve 70 is switched from the solenoid valve 64 to the switching valve 70.
To prevent supply of pressurized oil.

At the moment when the steam turbine is reset (returned) after the trip, the pressure oil in the oil cylinder 58 of the main steam stop valve 50 becomes zero. Further, even when the main steam stop valve 50 performs the full-circle injection operation, the pressure of the pressure oil supplied to the oil cylinder 58 is relatively low.

In this embodiment, attention is paid to such a point, and the pressure oil of the test drive valve 72 or the pressure oil of the oil cylinder 58 is supplied to the pressure oil pipe 80.
, The piston valve 81 is moved to the illustrated position to close the port, and the supply of pressure oil from the electromagnetic valve 64 to the switching valve 70 is cut off.

Therefore, according to this embodiment, during the full-circle injection operation, if the main steam stop valve 50 is open, the solenoid valve 64
Has a malfunction, and even if the pressure oil of the oil cylinder 58 or the test drive valve 72 is supplied via the electromagnetic valve 64, the switching valve 70
Cannot be pushed up, the switching valve 70 is not switched. For this reason, the control oil from the electro-hydraulic converter 66 continues to be sent to the oil cylinder 58 to the port 79 of the switching valve 70, and the main valve 54 and the sub-valve 55 are controlled to open. Transient closing of the main steam stop valve 50 due to a position change from the port to the port 75 can be suppressed. That is, even if the solenoid valve 64 malfunctions, the port 78 of the switching valve 70
Is not switched, it is possible to prevent transitional closing of the main steam stop valve 50, and to achieve a stable supply of steam to the steam turbine.

FIG. 6 is a control system diagram schematically showing a second embodiment of the steam turbine control device according to the present invention. The same parts as those of the first embodiment are denoted by the same reference numerals.

In the present embodiment, an interlock valve 82 is additionally provided to the electro-oil converter 66 so that pressure oil cannot be supplied from the electro-oil converter 66 to the oil cylinder 58 before the full-steam injection operation of the main steam stop valve 50. It is like that.

When the steam turbine is reset after the turbine trip, when no pressure oil remains in the electro-hydraulic converter 66, the interlock valve 82, as shown in FIG.
The piston valve 83 is moved by the pressing force of the emergency oil, and the pressure oil remaining in the valve is returned as a drain to a hydraulic generator (not shown).

However, when the steam oil turbine is reset, the electro-hydraulic converter 66 generates a valve opening signal due to some abnormality, and if the spool valve 67 is in a state of supplying the pressurized oil, the ports 84a and 84b of the interlock valve 82 are not provided. Is in an open state, so that the pressure oil of the electro-hydraulic converter 66 tends to flow to the oil cylinder 58 shown in FIG. 6 via the spool valve 67 and the interlock valve 82 as shown in FIG. In this case, the activation device 6
1. If an electrical failure occurs in the valve position control device 62 or the electric oil converter 66, the pressure oil cannot be cut off and the pressure oil presses the piston valve 83 of the interlock valve 82. Overcoming the emergency oil flowing to the oil cylinder 58 and the starting device 6
The main valve 54 and the sub-valve 55 are opened even though no full-circle injection operation command is issued to the main steam stop valve 50 from 1. For this reason, a large amount of steam flows to the steam turbine, and there is a possibility that the turbine shaft may run away.

This embodiment takes this point into consideration, and when the steam turbine is reset, a large amount of pressure oil flows from the electro-hydraulic converter 66 to the port 84a of the interlock valve 82 via the spool valve 67. Sometimes, as shown in FIG.
The oil pipe 8 connecting the interlock valve 82 to the spool valve 67 so that the pressure oil is also supplied to the port 84c.
5 is provided with a pressure oil branch pipe 86, and a piston valve 83 is formed by the pressing force of the pressure oil guided from the pressure oil branch pipe 86 to the port 84c.
Is moved to close the port 84a.

As described above, in the present embodiment, when a large amount of pressure oil flows from the electro-hydraulic converter 66 to the interlock valve 82 at the time of resetting the steam turbine, the electro-hydraulic converter 66 and the like have an electrical failure. Even when the flow cannot be suppressed, part of the oil flowing from the electro-oil converter 66 to the interlock valve 82 is guided to the port 84c via the pressure oil branch pipe 86, and the piston oil 83 is pressed by the pressure oil. Since the position of the port 84a is locked, the supply of the pressure oil to the oil cylinder 58 can be reliably cut off.

Therefore, according to the present embodiment, even if an electric accident occurs in the electro-hydraulic converter 66 or the like and the control of the pressure oil becomes impossible, the oil cylinder 66 Since the pressure oil flowing to 58 is reliably cut off by the interlock valve 82, the steam turbine can be continuously operated stably without the careless opening of the main steam stop valve 50. .

[0066]

As described above, the steam turbine control device according to the present invention, when resetting the steam turbine after the trip of the steam turbine, has a turbine control structure such as a starting device, a valve position control unit, and an electro-hydraulic converter. Even if there is an electrical failure in the parts and the supply of pressure oil to the steam valve cannot be suppressed, the supply of pressure oil to the steam valve is reliably cut off. With the means of blocking,
A sufficiently reliable operation can be performed by the steam turbine without providing redundancy such as multiplexing of circuits of turbine control components and multiplexing of power supplies thereof as in the related art.

In the steam turbine control device according to the present invention, during operation of the steam turbine at the rated load, an electrical failure occurs in the turbine control components, and the pressure oil required to open the valve body of the steam valve is opened. Even if the supply of oil is cut off, the pressure oil supply means is provided in a simple and low-cost structure that can reliably supply the pressure oil to the steam valve, so that the steam turbine can be operated stably. It has the effect.

[Brief description of the drawings]

FIG. 1 is a control system diagram schematically showing a first embodiment of a steam turbine control device according to the present invention.

FIG. 2 is a control system diagram schematically showing a first example of the first embodiment of the steam turbine control device according to the present invention.

FIG. 3 is an enlarged view of the switching valve in FIG. 2, showing a state before piston movement.

FIG. 4 is an enlarged view of the switching valve in FIG. 2, showing a state before piston movement.

FIG. 5 is a control system diagram schematically showing a second example of the first embodiment of the steam turbine control device according to the present invention.

FIG. 6 is a control system diagram schematically showing a second embodiment of the steam turbine control device according to the present invention.

FIG. 7 is an enlarged view of the interlock valve and the electro-hydraulic converter in FIG. 6, showing a state before the piston moves.

FIG. 8 is an enlarged view of the interlock valve and the electro-hydraulic converter in FIG. 6, showing a state before the piston moves.

FIG. 9 is a schematic system diagram showing a general power plant.

FIG. 10 is a control system diagram showing an example in which a conventional mechanical steam turbine control device is applied to a main steam stop valve.

FIG. 11 is a control system diagram showing an example in which a conventional electro-hydraulic steam turbine control device is applied to a main steam stop valve.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Steam generator 2 Main steam pipe 3 Main steam stop valve 4 Steam control valve 5 High pressure turbine 6 Turbine shaft 7 Low temperature reheat pipe 8 Reheater 9 High temperature reheat pipe 10 Reheat steam stop valve 11 Intercept valve 12 Medium pressure turbine 13 Cross Over pipe 14 Low pressure turbine 16 Generator 15 Condenser 17 Valve casing 18 Steam inlet 19 Steam outlet 20 Main valve 21 Sub valve 22 Valve rod 23 Piston 24 Oil cylinder 25 Disc dump valve 26 Control unit 27 Full-circle injection mechanism 28 Rod (Link mechanism) 29 Floating lever 30 Pilot valve 31 Valve test device 32 Motor 33 Handle 34 Piston valve 35 Trip valve 36 Air operated valve 37 Test drive valve 38 Solenoid valve 39 Latch 41 Piston 42 Spring 43, 44 Port 45 Starter 46 Valve Position control unit 47 Electro-oil converter 48 Spool valve 49 Valve position detector (differential transformer) 50 Main steam stop valve 51 Steam inlet 52 Steam outlet 53 Valve casing 54 Main valve 55 Secondary valve 56 Valve rod 57 Piston 58 Oil cylinder 59 Disk dump valve 60 Control unit 61 Starter 62 Valve position control unit 63 Valve position detector 64 Solenoid valve 64a Coil 64b Piston valve 65 Piston valve 66 Electro-oil converter 67 Spool valve 68 Bypass pipe 69 Valve test device 70 Switching valve 71 Air operated valve 72 Test drive valve 73 Piston valve 74 Nozzle 75, 77, 78 Port 76 Orifice 79 Emergency oil supply port 80 Pressure oil pipe 81 Piston valve 82 Interlock valve 83 Piston valve 84a, 84b, 84c Port 85 Oil pipe 86 Pressure oil branch pipe

Claims (8)

[Claims] 1. A valve test device and an electro-oil converter are combined with a main steam stop valve, and when a valve opening command is issued to the main steam stop valve from an activation device, the electro-oil converter is connected via a valve test device. In the steam turbine control device for supplying pressure oil to the oil cylinder of the main steam stop valve, a switching valve is provided at an outlet side of the electro-hydraulic converter, and after completion of the full circumference injection operation of the main steam stop valve, the switching is performed. A steam turbine control device comprising an electromagnetic valve that switches by driving a piston valve of the valve. 2. The switching valve is provided with a pressure oil system for directly supplying pressure oil from the electric oil converter and a bypass pipe for supplying pressure oil by bypassing the electric oil converter. The steam turbine control device according to claim 1, wherein 3. The switching valve supplies pressure oil from an electro-hydraulic converter to an oil cylinder of the main steam stop valve during a full-circle injection operation of the main steam stop valve, while providing a full-circle injection of the main steam stop valve. 3. The steam turbine control device according to claim 1, wherein after the operation is completed, pressure oil from a bypass pipe is supplied to an oil cylinder of the main steam stop valve. 4. The switching valve cuts off the supply of pressure oil from the electro-hydraulic converter after completion of the full circumference injection operation of the main steam stop valve and sends the pressure oil from the bypass pipe to the oil cylinder of the main steam stop valve. The steam turbine control device according to claim 2 or 3, further comprising a port for switching the piston valve by pressing the piston valve with another pressure oil so as to be supplied. 5. The solenoid valve includes a pressure oil pipe that presses a piston valve with pressure oil supplied from one of a valve test device and an oil cylinder of a main steam stop valve to close a port. The steam turbine control device according to claim 1, wherein: 6. A valve test device and an electro-oil converter are combined with a main steam stop valve, and when a valve opening command is issued to the main steam stop valve from an activation device, the electro-oil converter is connected via a valve test device. A steam turbine control device for supplying pressure oil to an oil cylinder of the main steam stop valve, wherein an interlock valve is provided on an outlet side of the electro-hydraulic converter. 7. The interlock valve includes a pressure oil branch pipe that presses a piston valve to close a port and cuts off pressure oil supplied from an electro-hydraulic converter to an oil cylinder of a main steam stop valve. The steam turbine control device according to claim 6, wherein: 8. A pressure oil branch pipe is bypassed from a pressure oil pipe connecting the interlock valve and a spool valve of the electro-hydraulic converter,
The steam turbine control device according to claim 7, wherein the steam turbine control device is connected to another port of the interlock valve.