JPS62159703A - Control apparatus of turbine - Google Patents

Abstract

PURPOSE:To enable any increase in the number of revolution to be controllable below a predetermined value, by eliminating both any delay of time in propagation from an electro-magnetic valve up to the pilot valve of a servomotor and a dead time of the pilot valve to its operation fine, in the case of interrupting a load on a turbine rotor. CONSTITUTION:A hydraulic pressure by a main oil pump 3 rotating together with a turbine shaft 1 is introduced in the pilot valve 31 of a servomotor 30 through operating oil pressure piping line 11 and oil pressure coming through the same valve 31 is introduced in a hydraulic cylinder 32 so as to drive the piston 33 of the hydraulic cylinder 32, and then a steam adjusting valve 41 is opened and closed by a lever 50. In this case, two piping lines 18, 19 communicating to spaces 32a, 32b formed by the piston 33 of hydraulic cylinder 32 are provided and the piping line 19 is connected to waste oil piping line through an electro-magnetic valve 19a and the piping line 18 is connected to the operating oil pressure piping line 11 through an electro-magnetic valve 18a. And in the case interrupting a load, both electro-magnetic valves 18, 19 are opened to elevate the piston 32 quickly and the steam adjusting valve 41 is quickly closed.

Description

[Detailed description of the invention] [Technical field to which the invention pertains]

The present invention relates to a turbine m control device that prevents an abnormal increase in rotational speed of a turbine axle during load interruption of the turbine.

[Prior art and its problems]

In recent years, the ratio of the moment of inertia of a turbine and a rotating machine coupled thereto, such as a turbine rotating body coupled to a generator, to the output has become smaller. For this reason, the rotational speed of the turbine rotating body increases significantly during load interruption. However, the increased rotational speed must be below a specified rotational speed that guarantees the safety of the turbine rotor. For this reason, a load shedding relay is added in addition to the normal speed governor W to detect the load fluctuation speed and quickly move the regulating valve in the closing direction to prevent an abnormal increase in the rotational speed. The prior art will be described below with reference to the drawings. FIG. 3 is a system diagram of a control device for a steam turbine as a conventional turbine. In FIG. The rotation speed of governor impeller 2
The hydraulic pressure is detected as hydraulic pressure (hereinafter referred to as secondary hydraulic pressure) and transmitted to the lower space 21a of the bellows 21 of the speed governor 20 via the primary hydraulic pressure line 10. Further, pressure oil discharged from the main oil pump 3 is guided to a pilot valve 31 of a servo motor 30 via an operating hydraulic pressure line 11. Note that this pressure oil is connected to pipe line 1.
Secondary hydraulic line 13 via throttle 12a provided in 2
It is led to the space 22c of the driven piston 22a of the driven piston device 22 and the bottom space 31a of the pilot valve 31 through the. The driven piston 22a is connected to a spring 22b fixed to the upper plate of the driven piston device 22, and the tip shaft 22d of the driven piston 22a communicates with the space 22c of the driven piston 22a via a flow path and opens on the side. Hole 22e
has been established. A lever 23 is fixed to the side wall 7 of the speed governor 220 and is movable up and down using the vinyl wind 23a as a fulcrum.
4 is installed. The sleeve 24 is provided with a hole 24a, into which the tip shaft 22d of the driven piston 22a is loosely inserted, and which passes through the side wall. A spring 25 is attached to the upper part of the lever 23 on the opposite side from the bellows 21.
A shaft 26a of a rotation speed setting device 26 is attached to the upper part of the spring 25. Further, the lower part of the spring 25 is connected to a shaft 21b fixed to the bellows 21 via a lever 23, so that the lever 23 and the spring 25 move up and down simultaneously with the movement of the bellows 21. The servo motor 30 is provided with a hydraulic cylinder 32, and a piston 33 divides the inside of the hydraulic cylinder 32 into two to form spaces 32a and 32b. The shaft 34 of the piston 33 is connected to the valve shaft 41a of the air control valve 41 via a lever 50 equipped with a rotation shaft 50a, and a connection point 50b between the lever 50 and the valve shaft 41a is pressed by a spring 42. ing. The pilot valve 31 is connected to the spaces 32a and 3 of the hydraulic cylinder 32.
Respective pipe lines 35a and 35b supply and discharge pressure oil to and from 2b.
is connected via. The upper part of the pilot valve 31 is pressed by a spring 36, and the spring force is determined by a feedback lever 37 according to the stroke of the piston 33. The pilot valve 31 is movable up and down within the casing, and is moved by the hydraulic pressure in the lower space 31a (secondary hydraulic pressure described in 1!) to supply pressure oil to one of the spaces 32a and 32b of the hydraulic cylinder 32. Then, the pressure oil is discharged from the other side and the piston 33 is moved. At this time, the pilot valve 31 returns to its original position by the force of the spring 36 caused by the feedback lever 37, the supply and discharge of pressure oil is stopped, and the position of the piston 33 is determined. In addition, a solenoid valve 5 which opens and closes the valve in response to an output signal from a load switching relay (not shown) is connected to a pipe line 14 branched from the secondary hydraulic line 13.
is provided. As is well known, a load shedding relay detects the load fluctuation speed of a turbine and outputs an output signal when this value is above a predetermined value, and does not output an output signal when it is below a predetermined value. Control of the turbine rotating body will be explained based on its configuration. When the load on the turbine increases and the rotational speed of the turbine rotating body decreases, the primary hydraulic pressure generated from the governor impeller 2 decreases. This secondary hydraulic pressure is then applied to the bellows 21 of the speed governor 20 through the pipe 10, and the bellows 21 descends to a position balanced with the force of the spring 25. Therefore, the lever 23 also goes down, and the sleeve 24 at its tip also goes down. By the way, when the turbine load is a certain value, the primary oil pressure corresponding to the rotation speed is applied to the bellows 21, and the position of the lever 23 is balanced with the force of the spring 25 according to the rotation speed set by the rotation speed setting device 26. is defined, and the hole 24a of the sleeve 24 at the tip and the hole 22e of the tip shaft 22d of the driven piston 22a are connected to the space 22 of the driven piston 22a.
A gap S is formed through which the oil is discharged by ramping so that the oil pressure in the space 22c balances the spring force of the spring 22b.The oil is discharged from this gap S as shown by the arrow, and the oil pressure in the space 22c (hereinafter referred to as secondary oil pressure) is formed. ) is determined. This secondary oil pressure determines the opening degree of the steam control valve 41 via the servo motor 30 degree lever 50 as will be described later. Therefore, when the rotational speed decreases, the sleeve 24 lowers, this gap S becomes smaller, and the secondary oil pressure increases. Then, this increased secondary oil pressure pulls the spring 22b, so that the gap S becomes larger again, and a higher secondary oil pressure than before which is balanced with the force of the spring 22b is maintained. This secondary hydraulic pressure passes through the secondary hydraulic pressure line 13 to the pilot valve 3.
1 and moves the pilot valve 31 upward against the force of the spring 36. Due to this movement, the pressure oil that has passed through the hydraulic pressure line 11 flows into the space 32b above one of the hydraulic cylinders 32 through communication between the annular groove of the pilot valve 31 and the lines 35a and 35b.
The pressure oil in the other lower space 32a is discharged, and the piston 3
3 moves downward. Therefore, the lever 50 connected to the piston shaft 34 rotates about the rotation shaft 50a, and the steam control valve 41 moves in the opening direction. At this time, the action of the feedback lever 37 changes the position of the steam control valve 41 as described above, that is, the position of the steam control valve 4.
1 is determined and can be adjusted to a predetermined load and rotation speed. Note that when the load on the turbine decreases, the primary oil pressure increases contrary to the above, and the secondary oil pressure decreases in proportion to this, and this secondary oil pressure moves the pyro valve 31 downward, causing the hydraulic cylinder 32 to move downward. Pressure oil flows into the space 32a, pressure oil in the upper space 32b is discharged, and the piston 32 moves upward to move the adjustment valve 41 in the closing direction, and the position of the adjustment valve is controlled by the action of the feedback lever 37. and adjusted to a predetermined load or rotation speed. By the way, when the load is suddenly lost, that is, when the load is cut off, the regulating valve moves in the closing direction as described above, but the output signal of the load shedding relay is given to the solenoid valve 5 to open the solenoid valve 5, and the regulating valve moves to the closing direction as described above. Direct pipe line 1 without going through the device 20
By reducing the secondary oil pressure of No. 3 to zero and closing the steam control valve '41, the closing time is shortened and an abnormal increase in the rotational speed of the turbine rotating body is prevented. Note that the output signal of the load shedding relay is output when the load fluctuation speed exceeds a predetermined value, so if the load fluctuation speed becomes less than the predetermined value, the output signal disappears, the solenoid valve 5 closes, and normal adjustment is resumed. speed device 20
The rotation speed of the turbine is controlled by the operation of the turbine. FIG. 4 is a block diagram showing the control system described above. In FIG. 4, the control system explained above is generally explained using a block diagram. In FIG. ing. The rotational speed of the turbine rotating body is converted into oil pressure (minus oil pressure) by the governor impeller 2 and transmitted to the speed governor 20 via the primary oil pressure pipe 10. In the speed governor 20, as described above, the secondary hydraulic pressure is transmitted to the pilot valve of the servo motor 30 via the conduit 14 as a secondary hydraulic pressure according to the rotation speed, and the magnitude of the secondary hydraulic pressure controls the hydraulic cylinder of the servo motor 30. The rotational speed of the turbine rotating body is changed by opening and closing the steam control valve 41 connected to the piston.
It controls the load. A load shifting relay 4 is provided which outputs an output signal from the power generation AT6 via an output converter 17 depending on the magnitude of the load fluctuation speed. As a result, when the load fluctuation speed during load shedding is greater than a predetermined value, the output signal is sent to the solenoid valve 5.
, the solenoid valve 5 is opened to discharge the secondary hydraulic pressure in the conduit 14 to zero, and the servo motor 30 rapidly closes the control valve 41 to prevent an abnormal increase in the rotational speed. However, after the electric Eft valve 5 is activated, the transmission delay time from the solenoid valve to the pilot valve and the operation time of the viroft valve become control dead time, and as a result of the steam continuing to flow into the turbine during this time, this energy is has the disadvantage that it promotes acceleration of the rotating body. Note that when the load fluctuation speed becomes less than a predetermined value, the solenoid valve 5 is closed because there is no output signal from the load shedding relay, and the rotational speed is controlled by the normal speed governor 20 via the servo motor 30. However, in recent years, the ratio of the moment of inertia of the turbine rotor to the output has become smaller, and even if the load shedding relay described above operates one valve and lowers the secondary oil pressure without going through the governor, Note that the dead time until the steam control valve closes is long, and during this time the turbine's air flow continues, which promotes an increase in the rotational speed of the turbine rotating body, and it is necessary to keep the increased rotational speed below the specified value for safety reasons. is becoming difficult.

[Purpose of the invention] SUMMARY OF THE INVENTION In view of the above-mentioned problems, an object of the present invention is to provide a turbine control device that can suppress an increase in rotational speed to a predetermined value or less when a load on a turbine rotating body is interrupted. [Key points of the invention]

According to the present invention, the above object is achieved by providing a piston in which the inner chamber of a cylinder of a servo motor is provided with first and second conduits communicating with spaces defined into two upper and lower chambers, and a second conduit communicating with an upper chamber. The first pipe line is connected to the drain oil pipe line via a magnetic valve, and the second pipe line communicating with the lower chamber is connected to the servo motor hydraulic oil line via a second 1tm valve. This is achieved by configuring the load shedding relay to open and operate the first and second solenoid valves together at No. 18 of the load shedding relay.

[Embodiments of the invention]

Embodiments of the present invention will be described below based on the drawings. FIG. 1 is a system diagram of a steam turbine control device according to an embodiment of the present invention. In FIG. 1, parts that are the same as those in the conventional example shown in FIG. 2 are given the same reference numerals. In FIG. 1, the turbine axle 1. Governor impeller 2. Main oil pump 3. a
li! ! Equipped with ff20.9-Bomotor 30. Lever 50.
Configuration of steam control valve 41, etc. Since the control is the same as that of the prior art, the explanation will be omitted. In this embodiment, a pipe is branched from the secondary hydraulic pipe 13 and releases pressure oil through a solenoid valve 5 that is activated by a signal from a load shedding relay. 14 has been abolished and replaced with hydraulic cylinder 3.
2 is divided into two by the piston 33, one end of which is connected to a space 32a into which pressure oil flows to close the regulating valve 41, and the other end is connected to the hydraulic pressure pipe 11, which is a pressure oil supply source. , and a conduit 18 comprising a solenoid valve 18a;
One end is connected to another space 32b for discharging pressure oil in the hydraulic cylinder 32, the other end is connected to an oil drain pipe, and the solenoid valve 1
A conduit 19 with 9a is provided. and 1l
The liff valves 18a and 19a are opened in response to an output signal generated when the load fluctuation speed of the load shedding relay is greater than a predetermined value. Therefore, when the load shedding relay outputs an output signal when the load shedding speed exceeds a predetermined value during load shedding, the solenoid valves 18a and 19a open simultaneously. Therefore, the pressure oil flows directly into the lower space 31a of the hydraulic cylinder 32 via the solenoid valve 18a through the pipe line 18 without passing through the pilot valve 31 of the servo motor 30, while the pressure oil in the upper space 32b Pipe line 1 via solenoid valve 19a
9 and is rapidly discharged to the discharge pipe. Therefore, the piston 32 rises and rapidly moves the steam control valve 41 in the closing direction via a lever 50 connected to the shaft of the piston. When the load fluctuation speed becomes less than a predetermined value, the output signal of the load shedding relay disappears, and both the solenoid valves 18a and 19a close. Therefore, the speed governor 2o performs normal rotational speed control of the turbine. FIG. 2 is a block diagram of the above control system, and in the figure, the turbine 15. Departure i4t! 16. Governor impeller 2.
Speed governor 20. Sakubo motor 30. Adjustment valve 41° output converter 17. The configuration and control of the load shuddering relay 4 and the like are the same as the conventional example shown in FIG. 4, so the description thereof will be omitted. In the figure, a hydraulic cylinder of a servo motor 30 communicates with a space divided into two by a piston, and each has a solenoid valve 1.
Conduits 18 and 19 with pipes 8a and 19a are provided. The solenoid valves 18a and 19a can be opened and closed simultaneously by the output signal of the load shedding relay 4. Therefore, when the load is cut off, the solenoid valves 18a and 19a are opened by the output signal of the load shedding relay that is issued because the load fluctuation speed exceeds a predetermined value, and the pressure oil is directly supplied to one of the two spaces of the hydraulic cylinder of the servo motor. and is discharged from the other side, rapidly moving the steam control valve in the closing direction. Note that when the load fluctuation speed becomes less than a predetermined value, the solenoid valve 18a is activated. 19a is closed and normal rotational speed control is performed. Negative by controlling as above? Pressure oil directly flows into the space below the servo motor piston that closes the steam control valve when fi is shut off, and pressure oil is discharged from the space above.As a result, the steam control valve closes for a short time. It is now possible to terminate the process. Therefore, there is no dead time in control, which consists of the transmission delay time from the solenoid valve to the pilot valve of the servo motor and the operation time of the pilot valve, as in the past, and the amount of residual air flowing into the turbine is reduced by this amount. The increase in the number can be suppressed to a predetermined value.

【Effect of the invention】

As is clear from the above description, according to the present invention, the pipe line for releasing pressure oil from the conventional control pressure oil circuit is eliminated, and instead it is replaced by the upper part of the piston of the hydraulic cylinder of the servo motor that opens and closes the steam control valve. , two pipes equipped with solenoid valves that open simultaneously in response to the output signal of the load shedding relay when the load is cut off are installed in the lower space, one pipe is connected to the pressure oil supply source, and the other is connected to the pressure oil supply source. By connecting it as a discharge pipe, pressure oil can flow in and out at the same time so as to move the steam control valve in the closing direction. Since the dead time between the transmission time delay and the operating time of the pilot valve is eliminated, the closing time of the steam control valve is shortened by this amount, and the amount of steam flowing into the turbine can be reduced. Therefore, the increase in the rotational speed of the turbine rotating body can be suppressed to below a predetermined value determined by safety standards.

[Brief explanation of drawings]

1 [M is a system diagram of a turbine control device according to an embodiment of the present invention, FIG. 2 is a system block diagram of FIG. 1, FIG. 3 is a system diagram of a conventional turbine control TJ device, and FIG. FIG. 4 is a system block diagram of the system diagram of FIG. 3; 2: Governor impeller, 3: Main oil pump, 4: Load shedding relay 5 = Solenoid valve, 15: Turbine, 18.1
9=pipe line, 18a, 19a: solenoid valve, 20: speed governor, 30: servo motor, 31: pilot valve, 32:
Hydraulic cylinder, 32a, 32b: Space, 33: Piston, 41: Adjustment valve.・2 people 4. ．． j2 d) Mouth ``drunkenness''
Figure 1 1υ Figure 2

Claims (1)

[Claims] The hydraulic pressure generated by the main oil pump and governor impeller, which rotate together with the steam turbine shaft, is transmitted to the servo motor as the operating hydraulic pressure for operating the steam control valve, and the latter hydraulic pressure is transmitted to the governor as the primary hydraulic pressure. A hydraulic oil pipe and a primary hydraulic pipe provided respectively, a secondary hydraulic pipe that interlocks between the servo motor and the speed governor via a driven piston, and an output detector provided in the generator. and a load shedding relay that responds to a signal from the servo motor, the first and second pipes respectively communicating with spaces defined by two upper and lower chambers by the piston in the cylinder interior of the servo motor. establish a road,
A first pipe line communicating with the upper chamber is connected to the drain oil pipe line via a first solenoid valve, and a second pipe line communicating with the lower chamber is connected to the hydraulic oil pipe line via a second solenoid valve. A control device for a steam turbine, characterized in that the first and second solenoid valves are connected to each other, and the first and second solenoid valves are both opened by a signal from the load shedding relay.