JPS62326B2 - - Google Patents

Description

[Detailed description of the invention] The present invention relates to a control device for a mixed pressure turbine.

As is well known, a mixing turbine is an industrial steam turbine that utilizes working steam used in factory equipment, and has multiple steam sources with different steam pressures.High-pressure steam is sent to the high-pressure stage of the turbine, and low-pressure steam is sent to an intermediate stage. It is constructed so that it can be introduced and effectively obtain power. Such a mixed pressure turbine is equipped with a steam control valve on each steam inlet side of the turbine for each steam source, and by adjusting the steam control valve, the amount of steam supplied to the turbine is controlled, and the speed of the turbine is controlled. Depending on the type of turbine, etc., a combination of front pressure control, back pressure control, output control, operation control at the time of turbine startup, emergency operation control when the mixed line side steam source is stopped, etc. is performed. In other words, there are various control modes as described above for controlling a mixed pressure turbine.
The control device must be configured to satisfy each of these control modes. Conventionally, a method for this purpose is to install a hydraulic servo motor for each steam control valve, and drive this hydraulic servo motor based on a control signal given in accordance with the selected control mode to control the opening of the control valve. The opening is adjusted to an appropriate degree. Note that the hydraulic servo motor used is one that is configured to output a stroke according to the magnitude of the input hydraulic signal applied to it, and furthermore, the hydraulic servo motor is configured to output a stroke according to the magnitude of the input hydraulic signal applied to it. In order to provide input signals, a signal converter is inserted in the control system to convert various control signals into hydraulic signals and establish the hydraulic pressure to be applied to the servo motor.

Next, the conventional control system for the mixed pressure turbine described above will be described with reference to FIGS. 1 and 2.
Here, a control device for a mixed pressure turbine is taken as an example, which includes a high pressure section and a low pressure section that are supplied with steam from a high pressure steam source 1 and a low pressure steam source 2. Steam from the high pressure steam source 1 is supplied to the high pressure section of the mixed pressure turbine 7 through the main steam stop valve 3 and the steam control valve 5, and works in the high pressure section and the low pressure section.
reach. On the other hand, steam from the low pressure steam source 2 is supplied to the low pressure section of the mixed pressure turbine 7 through the main steam stop valve 4 and the steam control valve 6, works in this low pressure section, and reaches the condenser 8. The total work of the mixed pressure turbine 7 is the sum of the work done by the high pressure steam and the low pressure steam. The turbine 7 has a governor impeller 9 connected directly to the shaft of the rotor, which establishes in a line 10 connected to it a primary hydraulic pressure whose pressure depends on the rotational speed of the rotor.

The primary hydraulic pressure established in the conduit 10 is controlled by the governor 11.
to go into. This governor uses the primary oil pressure as a detected value and compares it with a set value to establish and output a secondary oil pressure as an operation signal corresponding to the speed control signal, and converts the oil pressure into mechanical displacement. A signal converter 12 at the front stage, a mechanical-hydraulic signal converter 14, 1 that receives this mechanical displacement as a speed control signal 13 and converts it into a hydraulic signal to establish a secondary hydraulic pressure.
5, and a speed setting device 16 for initializing the relationship between the primary oil pressure and mechanical displacement in the converter 12.

Although the governor 11 can take various well-known forms, in this embodiment it has a configuration as shown in detail in FIGS. 2 and 3. That is, the converter 12 includes a governor bellows 17 that receives primary hydraulic pressure from the pipe line 10, a rod 18 that has one end attached to the pressure receiving surface of the bellows, and a rod 18 that is swingable about a pivot point 19. It includes a lever 21 connected to the other end of the lever. The subsequent signal converters 14 and 15 have the same configuration. In other words, as shown in Figure 3,
The signal converters 14 and 15 have a structure called a driven piston type, and have a pressure setting chamber 22, a piston 23, and a sleeve 24, and the sleeve 24 is fixed to the lever 21. The piston 23 and the sleeve 24 are provided with oil outflow holes 23a and 24a, respectively, and the pressure setting chamber 22 is supplied with high pressure oil from a high pressure oil supply source 29 through a high pressure oil pipe line 25, so that the piston 23 is pressed downward against the force of the tension spring 26. In such a configuration, the piston 23 descends to a position where its oil outflow hole 23a communicates with the oil outflow hole 24a of the sleeve 24 and is in an equilibrium state at that position, so that the pressure setting chamber 2
A hydraulic pressure is always established within the sleeve 24 which is sufficient to push the piston 23 down to the equilibrium position against the spring 26, in other words, a hydraulic pressure proportional to the position of the sleeve 24. Therefore, if the rotation of the turbine rotor falls below the set value given by the speed setting device 16,
When the primary oil pressure in the pressure setting chamber 22 decreases, the governor bellows 17 extends, swings the lever 21 clockwise as shown in the diagram, and lowers the sleeve 24, thereby reducing the secondary oil pressure in the pressure setting chamber 22. increase 2 as described below
Next, an increase in oil pressure increases the opening degree of the steam control valve and increases the rotation of the turbine rotor. The speed setting device 16 sends a signal to an initial setting adjustment mechanism consisting of a compression spring 27 that presses the lever 21 and an electric actuator 28 that changes the compression degree of the compression spring 27. This is used to initialize the relationship between changes in oil pressure and displacement of the lever 21. Reference numerals 14a and 15a in the driven piston type signal converters 14 and 15 are screws for adjusting the range of the secondary hydraulic pressure, respectively, and pull the spring 26 upward. By operating the screws 14a and 15a here, the spring force of the tension spring 26 changes,
The range of secondary oil pressure is adjusted. The secondary oil pressure established by the driven piston type signal converter 14 is transmitted as an input signal to the pilot valve of the servo motor 32 that drives the steam control valve 5 to open and close through the pipe 31, and is also transmitted to the pilot valve of the servo motor 32 by the signal converter 15. The thus established secondary oil pressure is transmitted to the servo motor 34 of the steam control valve 6 through the pipe line 33. Servo motor 3
Reference numerals 2 and 34 both operate to increase the opening degree of the steam control valve when the secondary oil pressure, which is an input signal, increases.

Furthermore, pressure detectors 35 and 36 are provided upstream of each of the main steam stop valves 3 and 4 to detect the inlet steam pressure. Pressure detectors 35 and 36 convert the detected pressure into hydraulic or electrical signals and send these to pressure regulators 37 and 44, respectively. The pressure regulator is set to a preset desired inlet vapor pressure by a signal 46.
and a signal converter 39 for steam pressure control called an impulse limiter that compares the signals from the detectors 35 and 36 and converts the steam pressure control signals 38 and 47 according to the difference into a hydraulic signal. Send to 45. These signal converters 39, 45 are, as shown in FIG.
Since the configuration is similar to that of the sleeves 41 and 4, a detailed explanation thereof will be omitted.
8 is different in that steam pressure control signals 38, 47 are converted into mechanical displacement by appropriate converters (not shown), and this mechanical displacement is transmitted by levers 42, 49. Ru. Therefore, pressure setting chamber 4
3 and 50, secondary oil pressure is established according to control signals 38 and 47. The relationship between the magnitude of the control signals 38, 47 and the magnitude of the hydraulic pressure set by the signal converters 39, 45 can be adjusted by changing the positions of the adjusting screws 39a, 45a. Moreover, the pressure setting chambers 43 and 50 of the signal converters 39 and 45 are in common with the pressure setting chamber 22 of the signal converters 14 and 15 mentioned above.
It is connected to the secondary oil pipes 31 and 33, that is, both are connected in parallel to the servo motors 32 and 34 to form a low value priority circuit, and therefore the pipes 31 and 3
The lower of the hydraulic pressures established in the pressure setting chambers is established in each of the servo motors 32 and 3.
4 will be controlled with priority given to low values.

Actual turbine operation control in the above configuration is performed as follows. That is, when selecting the speed control mode for both the high pressure section and the low pressure section of the turbine, the signal converter 3 as an impulse limiter is used.
2 by operating the adjustment screws 39a and 45a of 9 and 45.
Next, set the oil pressure range to high. Therefore, according to the principle of giving priority to low value oil pressure, secondary oil pressure according to the speed control signal 13 is applied to the servo motors 32 and 34,
The speed of the turbine is controlled by changing the opening degrees of the steam control valves 5 and 6. On the other hand, when selecting the front pressure control mode, the speed setter 16 is set to the maximum value and the secondary oil pressure of the signal converters 14 and 15 is set to a high value. As a result, the steam control valves 5 and 6 are driven according to the steam pressure control signals 38 and 47 via the signal converters 39 and 45 as impulse limiters based on the low-value oil pressure priority principle, and the Pressure control is performed to maintain the steam pressure at a constant value. Note that in the state in which these controls are performed, the turbine generator is connected to the electric power system and operated in parallel, so the speed change of the turbine remains minute, and there is almost no influence via the lever 21.

By the way, in the conventional control device, as mentioned above, the speed control system and other systems, such as the steam pressure control system, are individually controlled by two
Next, an independent driven piston-type machine for establishing hydraulic pressure - The device is configured with a hydraulic signal converter, which makes the device complex and expensive as a whole, and from this point of view, it is desired to simplify the device. .

This invention was made in consideration of the above points, and its purpose is to skillfully utilize the driven piston type mechanical-hydraulic signal converter that constitutes the governor of the speed control system, and to add only a small amount of mechanism to this. in,
It is now possible to perform not only speed control but also steam pressure control, output control, and other types of control that are compatible with the various operation control modes required for mixed pressure turbine operation without using a conventional impulse limiter. The purpose is to provide a control device.

This purpose is achieved by the present invention, which provides a mechanical-hydraulic signal converter constituting a governor of a speed control system.
An operating device is provided to adjust the hydraulic range adjustment mechanism based on an external signal, and operation control other than the speed control signal is provided, such as a pressure control signal according to the steam pressure of the steam source or an output control signal according to the turbine output. By selectively applying signals to the operating device corresponding to various control modes of the turbine, the signal converter of the governor establishes a hydraulic signal corresponding to other control signals such as pressure control, output control, etc., and controls the steam control valve. This is achieved by configuring the power to be applied to a hydraulic servo motor for driving.

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

In FIG. 4, driven piston-type mechanical-hydraulic signal converters 14 and 15, which are constituent parts of the governor, are connected to adjustment screws 14a and 15a as adjustment mechanisms for the secondary hydraulic range, and electric actuators are connected to them. 5
1,52 have been newly added. Then, by applying external signals to the operating devices 51 and 52, the positions of the adjusting screws 14a and 15a are changed, and the tension spring 26 (see FIG. 3) is expanded or relaxed, thereby changing the range of the secondary hydraulic pressure. . In addition, for each operating device 51, 52, the output signal of the speed setting device 16, pressure regulator 37, 44, and turbine generator 55 is compared with the output reference signal via control mode selection switches 53, 54. The circuit is configured such that each output signal of the output regulator 56 that obtains the output control signal is selectively applied. Note that the selection switches 53 and 54 are switched by commands from a central command and control panel.

Next, the operations of various control modes with the above configuration will be described. First, when selecting the speed control mode, move the selection switches 53 and 54 to the speed setter 16.
side, a signal is given to the operating devices 51 and 52, and the signal converters 14 and 15 are initialized in a predetermined hydraulic range. In this state, speed control is performed in the same manner as described in FIG.

Next, when selecting the prepressure control mode for the steam sources 1 and 2, first set the speed setter 16 to the maximum setting, push down the lever 21 in the signal converter 12 to the lowest position, and in this state press the selection switch. 5
3 and 54 to the pressure control position. Therefore, based on the output signals of the pressure regulators 37, 44, the actuators 51, 52 loosen the adjusting screws 14a, 15a and change the signal converter 1 as in the low value priority operation in the conventional device.
At steps 4 and 15, secondary oil pressure is established according to the front pressure control signals 38 and 47. This oil pressure is supplied by the servo motor 32,
34 as an input signal. As a result, the opening degrees of the control valves 5 and 6 are individually adjusted so as to maintain the front pressure constant. In the output control mode, the operation is performed in the same manner as in the prepressure control mode, except that the selection switches 53 and 54 are switched to the output regulator 56 side. Furthermore, although not shown in the drawings, when back pressure control of the turbine is required, the control signal obtained by the back pressure regulator is selectively applied to the operating device 51, in the same manner as described above.
52, it is possible to control the opening and closing of the steam control valves 5 and 6 so that the back pressure is constant.

In addition, in the case of a mixed pressure turbine, the procedure for starting this is stipulated to first start opening the steam control valve 5 in the high pressure section, and to start opening the mixed pressure steam control valve 6 in the low pressure section after a delay in the middle of speed-up. However, according to the configuration of this invention regarding this turbine startup,
By giving a signal to the actuators 51 and 52 of the signal converters 14 and 15 to set the individual secondary hydraulic pressure ranges in accordance with a predetermined starting program, the opening and closing control of the regulating valve can be performed according to a predetermined procedure. . Furthermore, in order to continue operating the turbine even when steam supply from either one of the steam sources 1 and 2 becomes impossible, the configuration shown in FIG. 4 detects the inoperation of the steam source. The signal obtained is given to the corresponding pressure regulator 37 or 44, and the pressure regulator that receives this signal gives a signal to the operating device so that it outputs the lowest secondary oil pressure to the signal converter 14 or 15. As a result, even if one steam regulating valve is fully closed, the control system for the other steam regulating valve can continue to operate the turbine.

As is clear from the above description, according to the present invention, an operating device is added to the hydraulic range adjustment mechanism of the driven piston type machine-hydraulic signal converter corresponding to each steam control valve that constitutes the governor of the speed control system. By installing a configuration in which pressure control signals, output control signals, etc. are selectively applied to each actuator, the same signal converter of the governor can be used to control not only speed control mode but also mixed pressure mode. Operation control can be performed in various control modes necessary for turbine operation. Therefore, the impulse limiter in the conventional device can be omitted, simplifying the device as a whole and reducing the cost.

[Brief explanation of the drawing]

Fig. 1 is an overall control system diagram using a conventional control device, Fig. 2 is a specific configuration diagram of the main parts in Fig. 1, and Fig. 3 is a diagram of the driven piston type machine-hydraulic signal converter in Fig. 2. FIG. 4 is a structural circuit diagram showing an embodiment of the present invention. 1, 2: Steam source, 5, 6: Steam control valve, 11:
Governor, 14, 15: Followed piston type machine - hydraulic signal converter, 16: Speed setter, 32, 34: Hydraulic servo motor, 37, 44: Pressure regulator, 5
1, 52: Operator, 53, 54: Control mode selection switch, 56: Output regulator.

Claims (1)

[Claims] 1. In an operation control device for a mixed pressure turbine, which controls the operation of steam supplied to the turbine from multiple steam sources with different pressures by adjusting the respective steam control valves, each steam control valve has a valve operating control device. A hydraulic servo motor and a governor including a mechanical-hydraulic signal converter for converting a speed control signal obtained by comparing a turbine rotation speed and a speed setting value to a hydraulic pressure and applying the same to the hydraulic servo motor, and further comprising: An operating device is provided to adjust the hydraulic range adjustment mechanism of the signal converter based on external signals, and speed control signals such as pressure control signals according to the steam pressure of each steam system or output control signals according to the turbine output are provided. 1. A control device for a mixed pressure turbine, characterized in that the control device is configured to selectively apply different turbine operation control signals to the operating device according to a control mode of the turbine.