JPS582402A - Control device of mixed pressure turbine - Google Patents

Abstract

PURPOSE:To control operation of a mixed pressure turbine in various control modes by newly providing controllers for an oil pressure range control mechanism of driven piston type mechanical-to-hydraulic signal convertors of which each is actuated with a steam regulation valve. CONSTITUTION:A mixed pressure turbine 7 is placed under control of steam regulation valves 5, 6. Controllers 51, 52 are newly provided for mechanical-to- hydraulic signal convertors 14, 15 which make up a governor of a speed control system. Output signals from a speed setter 16, pressure regulators 37, 44 and an output controller 56 are selectively sent to the controllers 51, 52 via related control mode selective switches 53, 54. By taking advantage of the signal convertor of the governor, operation control may be thereby performed in various control modes required for running of the mixed pressure turbine, as well as a speed control mode.

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 utilizes working steam used in factory equipment as an industrial steam turbine, and high-pressure steam is sent to the high-pressure stage of the turbine from multiple steam sources with different steam pressures.
The structure is such that low-pressure steam is introduced into an intermediate stage to 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 adjusted.
In addition to turbine speed control, front pressure control and back pressure control are performed depending on the turbine type.

This is performed in combination with output control, operation control at the time of turbine startup, and emergency operation control when the mixed line side steam source is stopped. That is, there are various control modes as described above for controlling the mixed pressure turbine, and 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 is composed of 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, performs work in the high pressure section and the low pressure section, and reaches the condenser 8. On the other hand, steam from the low pressure steam source 2 passes through the main steam stop valve 4 and the steam control valve 6, and is supplied to the low pressure section of the mixed pressure turbine. :,) The low pressure section does some work 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 f and the low pressure steam. turbine 7
has a governor sump valve 9 connected directly to the shaft of the rotor, which establishes in a line 10 connected to it a primary hydraulic pressure having a pressure depending on the rotational speed of the rotor.

The primary oil pressure established in line 10 enters governor 11 .

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.

Governor 11 can take a variety of well-known forms;
This embodiment has a configuration as shown in detail in FIGS. 2 and 3. That is, the converter 12 includes a governor bellows 17 that receives the primary oil pressure from the pipe line 10, a rod 18 whose one end is attached to the pressure receiving portion of the bellows, and a pivot point 19 that is swingable. The post-stage signal converters 14 and 15 including the lever 21 connected to the other end of the rod 18 have the same configuration. That is, as shown in FIG. 3, the signal converter 14, 15 has a so-called driven piston type structure, and has a pressure setting chamber 22, a piston 23, and a sleeve 24, and the sleeve 24 is fixed to the lever 21. The O piston 23 and the sleeve 24 each have an oil outflow hole 25.
g, 24a, 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 25, so that the piston 23 is pressed downward against the force of the tension spring 26. Ru. In such a configuration, the piston 23 descends to a position where its oil outflow hole 25a communicates with the oil outflow hole 24g of the sleeve 24, and is in an equilibrium state at that position. Hydraulic pressure sufficient to resist 26 and push it down to the equilibrium state position,
In other words, a hydraulic pressure proportional to the position of the sleeve 24 is established. Therefore, the rotation of the turbine rotor decreases below the set value given by the speed setting electric device 16, and the primary hydraulic pressure in the conduit 10 decreases. , the governor bellows 17 extends, swings the lever 21 clockwise as shown in the figure, and lowers the sleeve 24, thereby increasing the secondary oil pressure in the pressure setting chamber 22. Increasing the opening of the steam control valve increases the rotation of the turbine router.
and an electric actuator 2.8 that changes the degree of compression, and changes the degree of compression of the compression spring 27 to determine the relationship between the change in the primary oil pressure and the displacement of the lever 21. Reference numeral 14a in a driven piston type signal converter 14.15 is used for initial setting.

15g are screws for adjusting the range of the secondary hydraulic pressure, and pull the spring 26 upward. Screw 14 here! ,
By operating the screw 151, the spring force of the tension spring 26 is changed, and the range of the secondary hydraulic pressure is adjusted. The secondary oil pressure established by the driven piston type signal converter 14 is transmitted as an input signal to the pipe valve of the servo motor 32 that opens and closes the steam control valve 5 through the pipe line 31.
Further, the secondary oil pressure established by the signal converter 15 is not transmitted to the servo motor 64 of the steam control valve 6 through the line 63. The servo motors 52 and 34 are configured to 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 for detecting the inlet steam pressure are provided upstream of each of the main steam stop valves 3 and 4. The zero pressure detectors 35 and 36 convert the detected pressure into hydraulic or electrical signals. converted and sent to pressure regulators 57 and 44, respectively. The pressure regulator compares the signal 46 set at a preset desired inlet steam pressure with the signal from the detector 55.56, and converts the steam pressure control signal 38.47 corresponding to this difference into an oil pressure signal. The signal is sent to a signal converter 39.45 for steam pressure control called an impulse limiter. This signal converter 3
9.45 has the same configuration as the driven piston type signal converters 14 and 15 for speed control, as shown in FIG. 48 converts the steam pressure control signal 38.47 into a mechanical displacement by a suitable converter (not shown);
The difference is that this mechanical displacement is transmitted by levers 42, 49. Therefore, the pressure setting chamber 43°5
The magnitude of the 0 control signal 58.47 and the signal converter that establishes the secondary oil pressure according to the control signal 38.47! , 4
The relationship between the hydraulic pressure set by 5 is the adjustment screw 5.
Adjustment can be made by changing the positions of 9a and 45a. Also, the pressure setting chamber 43.50 of the signal converter 39.45
are connected to the secondary oil pipes 31, 33 in common with the pressure setting chamber 22 of the signal converter 14, 15 mentioned above, that is, both are connected in parallel to the servo motors 32, 54, forming a low value priority circuit. Therefore, the lower of the oil pressures established in the pressure setting chambers is established in the pipes 51 and 53, that is, the servo motors 52 and 34 are controlled with priority given to the lower value.

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 adjustment screw of the signal converter 69° 45 as an impulse limiter! 19g
, operate 45a to set the secondary 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 52 and 34, and the opening degrees of the steam control valves 5 and 6 are changed to control the speed of the turbine. On the other hand, when selecting the front pressure control mode, the speed setter 16 is set to the maximum setting and the secondary oil pressure of the signal converter 14, 15 is set to a high value. Due to the low oil pressure priority principle, the steam pressure control signal 1.4 is thereby transmitted via the signal converter 39, 45 as an impulse limiter.
7, the steam control valves 5 and 6 are driven in accordance with the
Pressure control is performed to maintain the vapor pressure at a constant value. Note that in the state where 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, for the speed control system and other systems such as steam pressure control system, independent driven piston type machine-hydraulic signal is used to establish the secondary oil pressure according to the control signal respectively. Since the device is configured with a converter, it has the disadvantage that the device as a whole is complicated and expensive, 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 is included in the governor of the speed control system, and to add only a small amount of mechanism to this. Now, it is possible to perform not only speed control but also steam pressure control, output control, and other control modes that are compatible with the various operation control modes required for mixed pressure turbine operation without using a conventional impulse limiter. The purpose of this invention is to provide a control device with

According to the present invention, the mechanical-hydraulic signal converter constituting the governor of the speed control system is provided with an operating device that adjusts the hydraulic range adjustment mechanism based on an external signal, thereby adjusting the steam pressure of the steam source. Governor signal conversion is achieved by selectively applying operation control signals other than the speed control signal, such as a pressure control signal corresponding to the turbine output or an output control signal corresponding to the turbine output, to the operating device corresponding to the various control modes of the turbine. This is achieved by establishing a hydraulic signal in response to other control signals such as pressure control and output control in the device, and supplying the signal to the hydraulic servo motor for driving the steam control valve.

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

In Fig. 4, driven screw 1, which is a component of the governor
Electric actuators 51 and 52 are newly added and connected to 4a and 15g. And the operating device 51゜52
adjusting screw 14j by applying an external signal to;
The range of the secondary hydraulic pressure is changed by changing the position of 15- and stretching or relaxing the tension spring 26 (see FIG. 3). In addition, for each operating device 51, 52, the output signal of the speed setting device 16, pressure regulator 57.44, and turbine generator 55 and the output reference signal are connected via the control mode selection switch 53.54. The circuit is configured such that each output signal of the output regulator 56, which obtains an output control signal by comparison, is selectively applied. Note that the selection switches 53 and 54 are switched by commands from a central command and control panel.

Next, operations in various control modes with the above configuration will be described. First, when selecting the speed control mode, switch the selection switches 53 and 54 to the speed setter 16 side, and
1.52 and to the signal converter 14.15,
Perform initial settings 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,
In this state, the selection switches 53 and 54 are switched to the pressure control position. Therefore, based on the output signal of the pressure gap lfJ device 37.44, the operating devices 51 and 52 adjust by 14 g and 15 g.
Similarly to the low value priority operation in the conventional device, the signal converter 14.15 establishes the secondary oil pressure in accordance with the front pressure control signal 38.47. given as. As a result, the opening degrees of the regulating valves 5 and 6 are individually adjusted so as to maintain the front pressure constant. In the output control mode, the operation is carried out in the same manner as in the front pressure 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 back pressure can be adjusted by selectively applying the control signal obtained from the back pressure regulator to the actuators 51 and 52 in the same manner as described above. Steam control valve 5 so that it is constant
It is possible to control the opening and closing of 6 degrees.

Furthermore, in the case of a mixed-pressure turbine, the procedure for starting the turbine is such that the high-pressure section steam control valve 5 should first be opened, and the low-pressure section mixed-pressure steam control valve 6 should begin to be opened at a later stage in the middle of the process. However, according to the configuration of the present invention regarding this turbidity activation, the operation device 5 of the signal converter 14.15
1, 52. By giving a signal to set the range of the secondary hydraulic pressure individually according to the predetermined startup program, the opening and closing control of the regulating valve can be controlled according to the predetermined procedure. In order to continue operating the turbine even when steam supply from one of them becomes impossible, the signal obtained by detecting the non-operation of the steam source in the configuration shown in Fig. The pressure regulator 31 or 44 that receives this signal may send a signal to the operating device so that the pressure regulator outputs the lowest secondary oil pressure to the signal converter 14 or 15. As a result, even if one steam control valve is fully closed, the control system for the other steam control valve remains active and the turbine can continue to operate.

As is clear from the above description, according to the present invention, the hydraulic range 1 of the driven piston type mechanical-hydraulic signal converter corresponding to each steam control valve constituting the governor of the speed control system is
By adding an operating device to the IItlrI mechanism and configuring it to selectively apply pressure control signals, output control signals, etc. to each operating device, it is possible to use the same signal converter in the governor to switch to speed control mode. The operation can be controlled in various control modes necessary for continuous operation of the mixed pressure turbine. Therefore, by omitting the impulse limiter in the conventional device, it is possible to simplify the device as a whole and reduce the cost.

[Brief explanation of the drawing]

Figure 1 is an overall control system diagram using a conventional control device;
The figure is a specific configuration diagram of the main parts in Figure 1, Figure 3 is a sectional view of the configuration of the driven piston type mechanical-hydraulic signal converter in Figure 2, and Figure 4 is a configuration circuit showing an embodiment of the present invention. It is a diagram. 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/hydraulic servo motor, 37, 44: Pressure regulator, 51° 52: Operator, 53, 54: Control Mode selection switch, 56
:Output regulator @

Claims (1)

[Claims] 1) In a mixed pressure turbine operation control device that controls the operation of steam supplied to the turbine from a plurality of steam sources with different pressures by adjusting the respective steam control valves,
A mechanical-hydraulic signal for converting the speed control signal obtained by comparing the turbine rotation speed and speed setting value into hydraulic pressure and applying it to the hydraulic servo motor for valve operation and the hydraulic servo motor for each steam control valve. A power panner including a converter is provided, and an operating device is further provided to adjust the hydraulic range adjustment mechanism of the signal converter based on an external signal,
A turbine operation control signal other than a speed control signal, such as a pressure control signal corresponding to the steam pressure of each steam system or an output control signal corresponding to the turbine output, is selectively applied to the operating device according to the control mode of the turbine. A control device for a mixed pressure turbine, characterized in that it is configured as follows.