JPH03267510A - Emergency stop device of steam turbine - Google Patents

Abstract

PURPOSE:To eliminate pressure rising even for a time in a hydraulic pressure lowering process in the exit ducts of a master trip valve and relay trip valve for improving stability and reliability by using the hydraulic pressure in a source hydraulic ducts as hydraulic pressure for switching the spool of a master trip valve. CONSTITUTION:A mechanical trip valve 4, which is operated when a steam turbine is in the state of emergency, and a master trip valve 10 provided with solenoid valves 23a and 23b, which are operated receiving an emergency signal, are arranged in series, and a steam valve is opened and closed by the hydraulic pressure of exit ducts 16 and 22 leading the hydraulic pressure of the exit duct 16 of the master trip valve 10 to the Y port 18 of a relay trip valve 17. In such constitution, the hydraulic pressure in a source hydraulic duct 5 is used as pressure for switching the spool 15 of the master trip valve 10. Since the spool 15 keeps its position as it is without moving with the actuation of the mechanical trip valve 4 by this constitution, the hydraulic pressure fluid is not obstructed even for a time. Therefore, both hydraulic pressure of exit ducts 16 and 22 can be smoothly lowered according to the actuation of only the mechanical trip valve 4.

Description

[Detailed Description of the Invention] [Objective of the Invention] (Industrial Application Field) The present invention provides an emergency stop device for a steam turbine, in particular, it is possible to safely emergency close a steam valve even when only a mechanical trip valve is activated. This invention relates to an emergency stop device for a steam turbine.

(Prior art) Steam turbines have a system for emergency closing of steam valves to stop the steam turbine and steam generator when the turbine speeds up abnormally or when vibrations exceeding the specified level occur in the steam turbine. An emergency stop device is generally provided.

FIG. 4 shows the configuration of a conventional emergency stop device for a typical steam turbine.

The turbine rotor 1 of the steam turbine is provided with an emergency governor 2 that operates when the turbine rotational speed increases to a specified number or more.The operation of the emergency governor 2 causes a mechanical trip via a link mechanism 3. Valve 4 is activated. This mechanical trip valve 4 is a hydraulic switching valve, and during operation of the steam turbine, the hydraulic pressure in the supply source hydraulic line 5 is
It is connected to this outlet port 6.

The outlet port 6 of the mechanical trip valve 4 is connected to the inlet port 8 of the lockout valve 7, and the inlet port 8 and the outlet port 9 of the lockout valve 7 are in communication during continuous operation of the steam turbine.

The secondary hydraulic pressure of the outlet port 9 of this lockout valve 7 is branched, one to the inlet port 11 of the master trip valve 10 and the other to the X port 12 of the master trip valve 10.
It is connected to the.

The hydraulic pressure supplied to the inlet port 11 of this master trip valve 10 is applied to this outlet port 1 during normal operation of the turbine.
3 will be contacted. On the other hand, the hydraulic pressure supplied to the X port 12 of the master trip valve 10 presses the spool 15 in the direction of arrow A via the orifice 14.

The outlet line 16 leaving the outlet port 13 of the master trip valve 10 is branched, one part directly to the disc dump valve (not shown) of the steam valve hydraulic cylinder and the other part to the relay trip valve 17. Connected to Y port 18. The hydraulic pressure supplied to the Y port 18 of the retry knob 17 presses the spool 19 in the direction of arrow B.

Incidentally, this relay trip valve 17 is supplied with hydraulic pressure from the source hydraulic line 5, and the inlet port 20 and outlet port 21 are communicated with each other during continuous operation of the steam turbine. Then, an outlet pipe 22 exiting from this outlet port 21
The oil pressure is at the outlet port 1 of the master trip valve 10.
The oil pressure in the outlet line 16 leaving the outlet line 3 is supplied to a disc dump valve (not shown) of a separate steam valve hydraulic cylinder.

Here, each steam valve hydraulic cylinder is activated when the oil pressure in the outlet line 16 that exits the outlet port 13 of the master trip valve 10 or the oil pressure in the outlet line 22 that exits the outlet port 21 of the relay trip valve 17 is lost. A disc dump valve operates to drain this internal hydraulic pressure and quickly close the steam valve.

In such an emergency stop device for a steam turbine, for example, when vibrations exceeding a specified number occur in the steam turbine, an emergency stop signal is sent to the solenoid valve 23 of the master trip valve 10.
a, 23b and the trip solenoid 24 that operates the mechanical trip valve 4 as an electrical signal.

As a result, the master trip valve 10 and the mechanical trip valve 4 operate simultaneously, but since the mechanical trip valve 4 receives power through the link mechanism 3, its operation is slightly delayed from that of the master trip valve 10. .

And the solenoid valves 23a, 23 of the master trip valve 10
By the operation of b, the X port 1 of the master trip valve 10
Hydraulic pressure in the hydraulic passage 25 after the orifice 14 continuous from the orifice 2 is discharged to the drain port 30 via the electromagnetic valves 23a and 23b. Therefore, the hydraulic pressure in the hydraulic passage 25 after the orifice 14 of the master trip valve 10 decreases, and the spool 15 of the master trip valve 10 moves in the direction opposite to the arrow A due to the elastic force of the spring 26.

By this operation of the spool 15 of the master trip valve 10, the communication between the inlet port 11 and the outlet port 13 of the master trip valve 10 is cut off, and the outlet port 13 and the drain port 27 are communicated with each other.
The oil pressure in the outlet line 16 of 0 is discharged through the outlet port 13 and the tren port 27 and drops rapidly.

This rapid drop in oil pressure in the outlet line 16 of the master trip valve 10 causes the Y port 18 of the relay trip valve 17 to
The oil pressure of the relay trip valve 17 also drops, and the spool 19 of the relay trip valve 17
Due to the elastic force of the spring 28, it moves in the direction opposite to the arrow B. By this operation of the spool 19, communication between the inlet port 20 and the outlet port 21 of the relay trip valve 17 is cut off, and the outlet port 21 is communicated with the drain port 29.

As a result, the oil pressure in the 80 line 22 of the relay trip valve 17 is discharged through the outlet port 21 and the drain port 29, and this oil pressure also drops rapidly.

Then, due to the sudden drop in oil pressure in the outlet line 16 of the master trip valve 10 and the outlet line 22 of the relay trip valve 7, the steam valve closes rapidly.

FIG. 5 shows how the oil pressure in the outlet line 16 of the master trip valve 10 and the outlet line 22 of the relay trip valve 17 decreases as the emergency stop device operates as described above. Fifth
In the figure, the horizontal axis represents time T, and the vertical axis represents oil pressure P. A solid line a represents the oil pressure in the outlet line 16 of the master trip valve 10, and a broken line represents the oil pressure in the outlet line 22 of the relay trip valve 17. shown respectively.

As can be seen from FIG. 5, the outlet pipe 16 of the master trip valve 10 and the relay trip valve 1 when the vibrations of the steam turbine exceed a specified number and the master trip valve 10 and the trip solenoid 24 simultaneously receive a stop signal.
The oil pressure in the outlet line 22 of No. 7 is normally lowered.

Next, the operation when the emergency governor 2 provided in the turbine rotor 1 is activated will be described.

When the rotational speed of the turbine exceeds a specified number, the emergency governor 2 is activated. Due to this operation of the emergency governor 2, the trip finger 32 of the emergency trip device 31 and the piston 33 are unlatched, and the mechanical trip valve 4 moves the link mechanism 3 in the direction of arrow C by the elastic force of the spring 34. Then, communication between the inlet port 35 and the outlet port 6 of the mechanical trip valve 4 is cut off, and the outlet port 6 is communicated with the drain port 36.

On the other hand, when the emergency governor 2 operates, the master trip valve 1
0 does not receive a direct activation signal from the emergency governor 2, so it is in a normal operating state.

Due to this operation of the mechanical trip valve 4, the hydraulic pressure from the source hydraulic line 5 is not supplied to the lockout valve 7, while the hydraulic pressure in the outlet line 16 of the master trip valve 10 is
Conversely, it is discharged from the drain port 36 through the outlet port 13 of the master trip valve 10 to the inlet port 11, the outlet port 9 to the inlet port 8 of the lockout valve 7, and the outlet port 6 of the mechanical trip valve 4 in this order.

Due to this discharge from the drain port 36, the pressure in the Y port 18 of the relay trip valve] 7 also begins to drop, and at the same time, the oil pressure in the hydraulic passage 25 after the orifice 14 of the master trip valve 10 also drops with a delay due to the effect of the orifice 14. Start. This drop in the oil pressure in the hydraulic passage 25 causes the spool 15 of the master trip valve 10 to move in the direction opposite to arrow A due to the elastic force of the spring 26.

In this way, the hydraulic pressure in the outlet line 16 of the master trip valve 10 is discharged from the drain port 36 of the mechanical trip valve 4 via the master trip valve 10 and the lockout valve 7, and during this discharge process, the hydraulic pressure in the outlet pipe 16 of the master trip valve 10
The spool 15 moves in the direction opposite to arrow A.

During the operation of the spool 15 of the master trip valve 10, the outlet port 13 of the master trip valve 10 is temporarily blocked by the spool 15. When this outlet port 13 is temporarily blocked by the spool 15, the hydraulic pressure from the outlet line 16 of the master trip valve 10 is no longer discharged. When the spool 15 completes its operation, the hydraulic pressure in the outlet line 16 is discharged again from the outlet port 13 through the drain port 27.

In this way, if there is a point in the discharge process of the hydraulic pressure in the outlet pipe 16 of the master trip valve 10 when this discharge temporarily disappears, the hydraulic pressure in the outlet pipe 16 rises again, albeit for a short time, during the descending process. It turns out.

The spool 19 of the relay trip valve 17 moves in the direction opposite to arrow B due to the drop in oil pressure in the outlet line 16 of the master trip valve 10, and the spool 19 of the relay trip valve 17 moves in the direction opposite to arrow B.
However, when the oil pressure in the outlet line 16 of the master trip valve 10 rises again, the spool 19 moves toward the arrow B.
direction, and stops the discharge of the hydraulic pressure from the outlet line 22 of the relay trip valve 17, and at the same time stops the discharge of the hydraulic pressure from the outlet line 22 of the relay trip valve 17.
This hydraulic pressure is supplied from the inlet port 20 of the relay trip valve 17 to the outlet line 22 via the outlet port 21. As a result, the oil pressure in the outlet pipe line 22 temporarily increases during the descending process.

That is, as shown in FIG.
The oil pressure a of the outlet pipe 16 at 0 is no longer discharged, while the oil pressure a of the outlet pipe 22 of the relay trip valve 17 is no longer discharged and the oil pressure of the source hydraulic pipe 5 is supplied. As a result, this oil pressure will rise significantly again.

FIG. 6 shows the master trip valve 10 when only the mechanical trip valve 4 operates due to the operation of the emergency governor 2.
outlet line 16 of the relay trip valve 17 and outlet line 2 of the relay trip valve 17
2 hydraulic behavior is shown. In FIG. 6, time T is plotted on the horizontal axis and oil pressure P is plotted on the vertical axis, where the solid line a is the oil pressure in the outlet pipe 16 of the master trip valve 10, and the broken line is the oil pressure in the outlet pipe 22 of the relay trip valve 17. are shown respectively.

Note that a pressure switch 41 is normally provided in the outlet pipe line 22 of the relay trip valve 17 to protect the reactor and boiler during emergency turbine shutdown. This pressure switch 41 is for detecting that the steam valve is rapidly closed due to a drop in oil pressure, and for making an emergency stop of the nuclear reactor or boiler.

As mentioned above, the outlet line 16 of the master trip valve 10
If this oil pressure temporarily rises during the falling process of the oil pressure in the outlet line 22 of the relay trip valve 17, the rapid closing of the steam valve will be delayed, resulting in a delay in the emergency stop of the steam turbine, or a pressure switch.

After the switch 41 operates once, it may return again and delay the emergency shutdown of the reactor or boiler.

(Problem to be Solved by the Invention) A conventional emergency stop device for a steam turbine normally quickly closes the steam valve when the mechanical trip valve 4 and the master trip valve 10 operate simultaneously, and safely shuts down the steam turbine and steam. If the generator can be stopped or only the mechanical trip valve 4 is activated, for example when the emergency governor 2 is activated when the speed of the turbine increases, the outlet line 16 of the master trip valve 10 And the oil pressure in the outlet pipe 22 of the relay trip valve 17 may temporarily rise again, which may delay the emergency stop of the steam turbine and the emergency stop of the steam generator due to the rapid closure of the steam valve. There were problems in ensuring the safety and reliability of steam turbines and steam generators.

In view of the above, the present invention provides the following:
Even if only the master trip valve operates, the temporary rise in oil pressure during the oil pressure drop process in the master trip valve outlet line and the relay trip valve outlet line is eliminated, and the steam valve is urgently closed and the steam turbine is shut down. The purpose of the present invention is to provide a device that can safely make an emergency stop to a steam generator or steam generator.

[Structure of the invention]

(Means for Solving the Problems) In order to achieve the above object, an emergency stop device for a steam turbine according to the present invention includes a mechanical trip valve that operates in an emergency of a steam turbine, and a mechanical trip valve that operates in response to an emergency stop signal of the steam turbine. A master trip valve equipped with a solenoid valve is arranged in series, and the hydraulic pressure in the outlet line of this master trip valve is guided to the Y port of the relay trip valve, so that the hydraulic pressure in the outlet line of the master trip valve and this relay are connected. An emergency stop device for a steam turbine in which the steam valve is opened and closed using the hydraulic pressure in the outlet pipe of the trip valve, characterized in that the hydraulic pressure in the supply source hydraulic pipe is used as the hydraulic pressure to switch the spool of the master trip valve. It is something.

(Function) According to the present invention configured as described above, when only the mechanical trip valve operates, the spool of the master trip valve is mechanically operated because the hydraulic pressure of the supply source hydraulic pipe is used as the hydraulic pressure for switching the spool. Since it does not operate in conjunction with the trip operation and maintains the same position, the hydraulic pressure discharge from the outlet pipe of this master trip valve is not temporarily blocked, and this allows only the mechanical trip valve to operate. Accordingly, both the oil pressure of the outlet pipe of the master trip valve and the outlet pipe of the relay trip valve can be lowered normally.

(Example) Embodiments of the present invention will be described below with reference to the drawings.

FIG. 1 shows a first embodiment of an emergency stop device according to the present invention. The steam turbine emergency stop device shown in this first embodiment is an improved version based on the conventional steam turbine emergency stop device shown in FIG. 4, and is made of the same components as the conventional emergency stop device. are given the same reference numerals and the description thereof will be omitted.

In FIG. 1, X port 1 of master trip valve 10
A hydraulic pipe line 5a branched from the supply source hydraulic line 5 is connected to 2, and the hydraulic pressure of the supply source is connected to the master trip valve 10
It is designed to be supplied to port 12.

By branching off the supply of hydraulic pressure to the X port 12 from the source hydraulic line 5 in this way, when only the mechanical trip valve 4 operates, the spool 15 of the master trip valve 10 does not operate. Master trip valve 1
The hydraulic pressure discharge from the outlet line 16 of 0 is not temporarily blocked. Further, since the oil pressure in the outlet pipe 16 does not rise during the lowering process, the spool 19 of the relay trip valve 17 does not temporarily move in the direction of arrow B, and therefore the outlet pipe 16 of the master trip valve 10 and the relay The oil pressure in the outlet line 22 of the trip valve 17 will both fall normally.

That is, in the steam turbine emergency stop device shown in FIG. Both trip solenoids 24 are operated. Since the mechanical trip valve 4 operates via the link mechanism 3, its operation is slightly delayed from that of the master trip valve 10.

Solenoid valve 23a of this master trip valve 10.

23b, the hydraulic pressure in the passage 25 extending from the X port 12 of the master trip valve 10 and beyond the orifice 14 is discharged from the drain port 30 via the solenoid valves 23a and 23b.

As a result, the spool 15 of the master trip valve 10 moves in the direction opposite to the arrow A, and the oil pressure in the outlet line 16 of the master trip valve 10 and the outlet line 22 of the relay trip valve 17 decreases, as in the conventional example described above. It is similar to

In other words, when the trip solenoid 24 and the master trip valve 10 receive a stop signal at the same time, the drop in oil pressure in the outlet line 16 of the master trip valve 10 and the outlet line 22 of the relay trip valve 17 is as shown in FIG. 5 of the conventional example. The behavior is the same as shown.

On the other hand, when the emergency governor 2 is activated due to an increase in the turbine speed, the oil pressure in the outlet line 16 of the master trip valve 1o is changed from the outlet port 13 of the master trip valve 1° to the inlet port 11 to the lockout valve 7. It will be discharged from the drain port 36 through the outlet port 9, the inlet port 8, and the outlet port 6 of the mechanical trip valve 4 in this order.

Even in the process of discharging the hydraulic pressure from the outlet pipe 16 of the master trip valve 10, the X port 12 of the master trip valve 10 is supplied with the hydraulic pressure from the source hydraulic pipe 5. 25 oil pressure does not drop. Therefore, spool 1 of master trip valve 10
5 is maintained in a pressed state in the direction of arrow A by the hydraulic pressure of this hydraulic passage 25. Therefore, the oil pressure in the outlet pipe line 16 of the master trip valve 10 is smoothly discharged and lowered through the discharge path.

As the oil pressure in the outlet line 16 of the master trip valve 10 decreases, the oil pressure in the Y port 18 of the relay trip valve 17 also decreases, and the spool 19 moves in the opposite direction to arrow B. This oil pressure drops by discharging the oil pressure.

In this way, when only the mechanical trip valve 4 operates during the operation of the emergency governor 2, etc., the behavior of the hydraulic pressure in the outlet line 16 of the master trip valve 10 and the outlet line 22 of the relay trip valve 17 is controlled. Shown in Figure 2. Here, time T is plotted on the horizontal axis and oil pressure P is plotted on the vertical axis, where the solid line a shows the oil pressure in the outlet pipe line 16 of the master trip valve 1o, and the broken line shows the oil pressure in the outlet pipe line 22 of the relay trip valve 17, respectively. .

In this way, in this embodiment, not only when the trip solenoid 24 and the master trip valve 1o receive a stop signal at the same time, but also when only the mechanical trip valve 4 is operated, such as when the emergency governor 2 is operated. The phenomenon in which the oil pressure temporarily rises during the falling process is eliminated, and it falls smoothly, making it possible to safely bring the steam turbine and steam generator to an emergency stop, resulting in a highly reliable steam turbine. Acts as an emergency stop device.

FIG. 3 shows a second embodiment of the emergency stop device for a steam turbine according to the present invention, and the differences from the first embodiment are as follows.
A sequence valve 51 is provided in the branch hydraulic line 5a from the source hydraulic line 5 extending to the X port 12 of the master trip valve 10, and the pilot pressure of this sequence valve 51 is connected to the outlet port 9 of the lockout valve 7. The sequence valve 51 can be switched by a drop in the pressure in the inlet port 11 as the oil pressure in the outlet pipe 16 of the master trip valve 10 is lowered by leading from a pipe connecting the inlet port 11 of the master trip valve 10. That's what I did.

As a result, the drop in oil pressure in the outlet line 16 of the master trip valve 10 and the outlet line 22 of the relay trip valve 17 is the same as in the first embodiment, but the sequence valve 51
After the hydraulic pressure in the outlet pipe 16 of the master trip valve 10 and the outlet pipe 22 of the relay trip valve 17 has completely decreased, the supply of hydraulic pressure to the X port 12 of the master trip valve 10 is cut off. After the turbine has come to an emergency stop, the spool 1 of the master trip valve 10
5 in the opposite direction of the arrow to open the master trip valve 1.
0 can be maintained in the turbine stopped state.

〔Effect of the invention〕

Since the emergency stop device for a steam turbine according to the present invention is configured as described above, the outlet pipe of the master trip valve can be operated not only when the mechanical trip valve and the master trip valve operate together, but also when only the mechanical trip valve operates. The hydraulic pressure in the outlet line of the relay trip valve and the outlet line of the relay trip valve is smoothly lowered without being temporarily increased, and the steam valve is urgently closed, thereby safely stopping the steam turbine and the steam generator, thereby increasing the safety of the steam turbine and the steam generator. This has the effect of ensuring reliability and reliability.

[Brief explanation of drawings]

Fig. 1 is a configuration diagram showing an embodiment of the emergency stop device for a steam turbine according to the present invention, and Fig. 2 shows the outlet pipe of the master trip valve and the relay trip when only the mechanical trip valve operates in this embodiment. 3 is a block diagram showing another embodiment of the emergency stop device for a steam turbine according to the present invention; FIG. 4 is a block diagram showing a conventional example; FIG. The figure shows the hydraulic pressure behavior of the outlet pipe of the master trip valve and the outlet pipe of the relay trip valve when the mechanical trip valve and master trip valve operate in this conventional example. It is a figure equivalent figure. 1... Turbine rotor, 2... Emergency governor, 4...
・Mechanical trip valve, 5... Supply source hydraulic pipe, 5
a... Branch hydraulic pipe line, 7... Lockout valve, 10
... Master trip valve, 14 ... Orifice, 1
5... Spool, 16... Outlet pipe line, 17... Relay trip valve, 18... Y port, 19... Spool, 22... Outlet pipe line, 23 a, 23 b.
...Solenoid valve, 24...Trip solenoid, 25...
・Passage, 51...Sequence valve.

Claims (1)

[Claims] A mechanical trip valve that operates in the event of a steam turbine emergency and a master trip valve equipped with a solenoid valve that operates in response to an emergency stop signal of the steam turbine are arranged in series, and the hydraulic pressure of the outlet pipe of this master trip valve is controlled. In the emergency stop device for a steam turbine, the master trip valve is guided to the Y port of the relay trip valve and opens and closes the steam valve using the hydraulic pressure in the outlet pipe of the master trip valve and the hydraulic pressure in the outlet pipe of the relay trip valve. An emergency stop device for a steam turbine, characterized in that hydraulic pressure from a supply hydraulic line is used as hydraulic pressure to switch a valve spool.