Turbine valve control device, turbine facility, and turbine valve drive system

Abstract

To provide a turbine valve control device capable of reducing wear of a sliding part.SOLUTION: A turbine valve control device according to an embodiment includes: a flow control circuit for outputting a control valve opening command signal for a turbine flow control valve; and an opening control circuit for outputting a servo valve opening command signal to a servo valve based on the control valve opening command signal and an opening feedback signal of the turbine flow control valve. An output deviation signal which is a difference between the control valve opening command signal and the opening feedback signal is multiplied by a servo gain. A servo gain when an absolute value of the output deviation signal is a first reference value or less, is smaller than a servo gain when the absolute value of the output deviation signal is a second reference value or more which is larger than the first reference value.SELECTED DRAWING: Figure 2

Description

Technical Field

[0001] The present embodiment relates to a turbine valve control device, a turbine facility, and a turbine valve drive system.

Background Art

[0002] Generally, in a steam turbine facility for thermal power generation, in order to adjust the rotational speed of a steam turbine and the power generation output of a generator, the flow rate of steam as a working fluid supplied to the steam turbine is controlled. The flow rate of steam is adjusted by a steam control valve or the like. The driving of the steam control valve and the adjustment of the opening degree of the steam control valve are performed by a steam control valve drive system.

[0003] The steam control valve drive system includes an oil cylinder device, a hydraulic pressure generating device, a servo valve, and a steam control valve control device. The oil cylinder device includes a piston directly connected to the valve rod of the steam control valve and a cylinder in which the piston is housed. A hydraulic pressure generating device is connected to the oil cylinder device, and the amount of high-pressure control oil supplied from the hydraulic pressure generating device to the oil cylinder device is adjusted by the servo valve. The opening degree of the servo valve is adjusted by the steam control valve control device. As a result, the amount of high-pressure control oil supplied to the cylinder of the oil cylinder device is adjusted, and as a result, the opening degree of the steam control valve is adjusted.

[0004] The steam control valve control device outputs a servo valve opening command signal calculated using an electro-hydraulic control method (EHC) to the servo valve to control the servo valve. The servo valve opening command signal is calculated from an opening deviation that is the difference between a command opening corresponding to a flow rate command value and a feedback opening of the steam control valve.

[0005] The electro-hydraulic control method is superior in responsiveness to the conventional mechanical hydraulic control method. Due to this, even when the opening deviation described above is small, the valve body of the steam control valve moves rapidly. For this reason, sliding parts such as the valve body, valve rod, and oil cylinder device are likely to be worn. In addition, due to the recent popularization of renewable energy power generation facilities, it is expected that many minute fluctuations in the load on the generator of the turbine facility will occur. In this case, the frequency of occurrence of minute fluctuations in the opening deviation increases, and there is a concern that the wear of the sliding parts will progress.

Prior Art Documents

Patent Documents

[0006]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0007] An embodiment aims to provide a turbine valve control device, a turbine facility, and a turbine valve drive system that can reduce the wear of sliding parts.

Means for Solving the Problems

[0008] The turbine valve control device according to the embodiment is a device that controls a servo valve for controlling the opening degree of a turbine flow control valve that adjusts the flow rate of the working fluid supplied to the power generation turbine using high-pressure control oil. The turbine valve control device includes a flow control circuit that outputs a control valve opening degree command signal for the turbine flow control valve based on a turbine speed signal or a load signal, and an opening degree control circuit that outputs a servo valve opening degree command signal to the servo valve based on the control valve opening degree command signal and the opening degree feedback signal of the turbine flow control valve. The opening degree control circuit includes a servo valve circuit subtraction unit that calculates the difference between the control valve opening degree command signal and the opening degree feedback signal as an output deviation signal, and a servo amplification unit that calculates a deviation amplification signal by multiplying the output deviation signal by a servo gain set based on the output deviation signal. The servo gain when the absolute value of the output deviation signal is less than or equal to the first reference value is smaller than the servo gain when the absolute value of the output deviation signal is greater than or equal to a second reference value that is greater than the first reference value.

[0009] The turbine valve control device according to the embodiment is a device that controls a servo valve for controlling the opening degree of a turbine flow control valve that adjusts the flow rate of the working fluid supplied to the power generation turbine using high-pressure control oil. The turbine valve control device includes an input deviation calculation circuit that calculates the difference between the turbine speed signal or the load signal and the corresponding required signal as an input deviation signal, a flow control circuit that outputs a control valve opening degree command signal for the turbine flow control valve using the input deviation signal, and an opening degree control circuit that outputs a servo valve opening degree command signal to the servo valve based on the control valve opening degree command signal and the opening degree feedback signal of the turbine flow control valve. The opening degree control circuit includes a servo valve circuit subtraction unit that calculates the difference between the control valve opening degree command signal and the opening degree feedback signal as an output deviation signal, and a servo amplification unit that calculates a deviation amplification signal by multiplying the output deviation signal by a servo gain set based on the input signal. The servo gain when the absolute value of the input deviation signal is less than or equal to the first reference value is smaller than the servo gain when the absolute value of the input deviation signal is greater than or equal to a second reference value that is greater than the first reference value.

[0010] The turbine valve drive system according to the embodiment is a system that drives a turbine flow control valve for adjusting the flow rate of the working fluid supplied to the power generation turbine. The turbine valve drive system includes an oil cylinder device that drives the turbine flow control valve, a servo valve that adjusts the amount of high-pressure control oil supplied to the oil cylinder device, a control oil line connecting the oil cylinder device and the servo valve, a solenoid valve provided in the control oil line, a bypass line that connects the oil cylinder device and the servo valve and bypasses the solenoid valve, a first orifice provided in the bypass line, and a turbine valve control device. The turbine valve control device includes a flow control circuit that outputs a control valve opening command signal for the turbine flow control valve based on a turbine speed signal or a load signal, and an opening control circuit that outputs a servo valve opening command signal to the servo valve based on the control valve opening command signal and the opening feedback signal of the turbine flow control valve. The opening control circuit includes a servo valve circuit subtraction unit that calculates the difference between the control valve opening command signal and the opening feedback signal as an output deviation signal. The turbine valve control device controls the solenoid valve to close when the absolute value of the output deviation signal is less than or equal to a first reference value, and to open when the absolute value of the output deviation signal is greater than or equal to a second reference value that is greater than the first reference value.

[0011] The turbine valve drive system according to the embodiment is a system that drives a turbine flow control valve for adjusting the flow rate of the working fluid supplied to the power generation turbine. The turbine valve drive system includes an oil cylinder device that drives the turbine flow control valve, a servo valve that adjusts the amount of high-pressure control oil supplied to the oil cylinder device, a control oil line connecting the oil cylinder device and the servo valve, a solenoid valve provided in the control oil line, a bypass line that connects the oil cylinder device and the servo valve and bypasses the solenoid valve, a first orifice provided in the bypass line, and a turbine valve control device. The turbine valve control device includes an input deviation calculation circuit that calculates the difference between the turbine speed signal or the load signal and the corresponding required signal as an input deviation signal, a flow control circuit that outputs a control valve opening command signal for the turbine flow control valve using the input deviation, and an opening control circuit that outputs a servo valve opening command signal to the servo valve based on the control valve opening command signal and the opening feedback signal of the turbine flow control valve. The turbine valve control device controls the solenoid valve to close when the absolute value of the input deviation signal is less than or equal to a first reference value, and to open when the absolute value of the input deviation signal is greater than or equal to a second reference value that is greater than the first reference value.

Advantages of the Invention

[0012] According to the embodiment, wear of sliding parts can be reduced.

Brief Description of the Drawings

[0013]

Figure 1

Figure 2

Figure 3

Figure 4

Figure 5

Figure 6

Figure 7

Figure 8

MODE FOR CARRYING OUT THE INVENTION

[0014] Hereinafter, with reference to the drawings, a turbine valve control device, a turbine facility, and a turbine valve drive system according to the invention of the present embodiment will be described.

[0015] (First Embodiment) First, with reference to FIGS. 1 to 5, a turbine valve control device, a turbine facility, and a turbine valve drive system according to the first embodiment will be described.

[0016] As shown in FIG. 1, a turbine facility 1 according to the present embodiment includes a steam generator 2, a steam turbine 3, a main steam stop valve 4, a steam control valve 5, a generator 6, and a steam control valve drive system 10. The steam turbine 3 is an example of a power generation turbine. In the present embodiment, the turbine facility 1 including the steam turbine 3 will be described as an example. The power generation turbine may be a gas turbine instead of the steam turbine 3.

[0017] The steam generated by the steam generator 2 (e.g., a boiler) is supplied to the steam turbine 3 as a working fluid. The supply of steam to the steam turbine 3 is controlled by the main steam stop valve 4 and the steam control valve 5. The main steam stop valve 4 is a valve for shutting off the supply of steam to the steam turbine 3 in case of an abnormality. The steam control valve 5 is a valve for adjusting the flow rate of the steam supplied to the steam turbine 3. The steam control valve 5 is an example of a turbine flow control valve. The steam turbine 3 is driven by the supplied steam. As a result, the fluid energy of the steam is converted into rotational energy, and a turbine rotor (not shown) is rotationally driven. The generator 6 is connected to the turbine rotor, and the rotational energy of the turbine rotor is converted into electrical energy to generate electricity. In this way, an electric power output is obtained from the generator 6. The steam discharged from the steam turbine 3 is condensed in the condenser 7 to become condensate. The condensate is supplied to the steam generator 2 by the feed water pump 8. The condensate is heated by a feed water heater (not shown).

[0018] The steam control valve drive system 10 is a system for driving the above-described steam control valve 5. The steam control valve drive system 10 is an example of a turbine valve drive system. The opening degree of the steam control valve 5 driven by the steam control valve drive system 10 affects the rotational speed and load (electric power output) of the steam turbine 3. Therefore, the steam control valve drive system 10 is required to have high accuracy and high responsiveness.

[0019] The steam control valve drive system 10 includes an oil cylinder device 11, a servo valve 12, a hydraulic pressure generating device 13, and a steam control valve control device 20.

[0020] The oil cylinder device 11 drives a valve body (not shown) of the steam control valve 5 using high-pressure control oil. The oil cylinder device 11 includes a piston 11a connected to the valve body of the steam control valve 5 via a valve rod (not shown), and a cylinder 11b that houses the piston 11a.

[0021] The servo valve 12 controls the opening degree of the steam control valve 5 using high-pressure control oil. The servo valve 12 is a valve for adjusting the amount of high-pressure control oil supplied to the cylinder 11b of the oil cylinder device 11. By adjusting the amount of high-pressure control oil by the servo valve 12, the opening degree of the steam control valve 5 is controlled. The servo valve 12 is controlled by a servo valve opening degree command signal h (described later) transmitted from the above-described steam control valve control device 20.

[0022] The hydraulic pressure generating device 13 supplies control oil to the oil cylinder device 11. The hydraulic pressure generating device 13 is connected to the servo valve 12 via the high-pressure oil pipe 14.

[0023] With such a configuration, the high-pressure control oil is supplied from the hydraulic pressure generating device 13 to the cylinder 11b via the servo valve 12. The amount of high-pressure control oil supplied to the cylinder 11b is adjusted by the servo valve 12. By the high-pressure control oil supplied to the cylinder 11b, the piston 11a slides within the cylinder 11b, and the position of the valve body of the steam control valve 5 is adjusted.

[0024] Next, the steam control valve control device 20 according to the present embodiment will be described with reference to FIG. 2. The steam control valve control device 20 is an example of a turbine valve control device. The steam control valve control device 20 is a device for controlling the above-described servo valve 12.

[0025] As shown in FIG. 2, the steam control valve control device 20 includes a turbine speed deviation calculation circuit 21, a load deviation calculation circuit 22, a flow control circuit 23, and an opening degree control circuit 24.

[0026] The turbine speed deviation calculation circuit 21 is an example of an input deviation calculation circuit. The turbine speed deviation calculation circuit 21 is configured to calculate the difference between the turbine speed signal a1 and the turbine speed demand signal a2 as the turbine speed deviation signal a3 and output it. The turbine speed deviation signal a3 is an example of an input deviation signal. The turbine speed signal a1 is a signal indicating the rotational speed of the steam turbine 3. The turbine speed signal a1 is transmitted from the rotational speed measuring device 16 shown in FIG. 1. The rotational speed measuring device 16 is configured to measure the rotational speed of the steam turbine 3. The turbine speed demand signal a2 is transmitted from a higher-level control device (not shown).

[0027] The turbine speed deviation calculation circuit 21 may include a turbine speed subtraction unit 25. The turbine speed subtraction unit 25 calculates the difference between the turbine speed signal a1 and the turbine speed demand signal a2 described above as the turbine speed deviation signal a3. The turbine speed subtraction unit 25 may output the turbine speed deviation signal a3 to the load deviation calculation circuit 22.

[0028] The load deviation calculation circuit 22 is an example of an input deviation calculation circuit. The load deviation calculation circuit 22 is configured to calculate the difference between the load signal b1 and the load demand signal b2 as the load deviation signal b3 and output it. The load deviation signal b3 is an example of an input deviation signal. The load signal b1 is a signal indicating the load of the generator 6. The load signal b1 is transmitted from the load measuring device 17 shown in FIG. 1. The load measuring device 17 is configured to measure the load of the generator 6 and may be, for example, a wattmeter that measures the power output of the generator 6. The load demand signal b2 may be transmitted from a higher-level control device (not shown).

[0029] The load deviation calculation circuit 22 may include a load subtraction unit 26. The load subtraction unit 26 calculates the difference between the load signal b1 and the load demand signal b2 described above as the load deviation signal b3. The load subtraction unit 26 may output the load deviation signal b3 to the required flow rate calculation unit 27 described later together with the turbine speed deviation signal a3.

[0030] As described above, the turbine speed deviation signal a3 output from the turbine speed deviation calculation circuit 21 is output to the load deviation calculation circuit 22. That is, the turbine speed deviation calculation circuit 21 and the load deviation calculation circuit 22 are connected in series. However, the turbine speed deviation calculation circuit 21 and the load deviation calculation circuit 22 may be connected in parallel. In this case, the turbine speed deviation signal a3 output from the turbine speed deviation calculation circuit 21 may be output to the required flow rate calculation unit 27 instead of the load deviation calculation circuit 22.

[0031] The flow rate control circuit 23 is configured to calculate a flow rate command value based on the turbine speed signal a1 or the load signal b1 and output a steam control valve opening command signal d for the steam control valve 5. In the present embodiment, the flow rate control circuit 23 outputs a steam control valve opening command signal d using the above-described turbine speed deviation signal a3 or the above-described load deviation signal b3 as an input signal. The flow rate control circuit 23 includes a required flow rate calculation unit 27 and a control valve opening command signal calculation unit 28.

[0032] The required flow rate calculation unit 27 calculates and outputs a required flow rate signal c using the turbine speed deviation signal a3 or the load deviation signal b3 as an input signal. More specifically, the required flow rate calculation unit 27 may multiply the turbine speed deviation signal a3 or the load deviation signal b3 by a predetermined gain to calculate a flow rate command value. The calculated flow rate command value is output as the required flow rate signal c. The required flow rate calculation unit 27 may select one of the turbine speed deviation and the load deviation as an input signal used for calculating the flow rate command value based on a command from a higher-level control device.

[0033] The control valve opening command signal calculation unit 28 converts the required flow rate signal c output from the required flow rate calculation unit 27 into an opening of the steam control valve 5 and outputs it as the steam control valve opening command signal d. The steam control valve opening command signal d is an example of a control valve opening command signal. The relationship between the flow rate and the opening of the steam control valve 5 is stored in advance in the control valve opening command signal calculation unit 28, and the control valve opening command signal calculation unit 28 outputs the steam control valve opening command signal d based on this relationship.

[0034] The opening control circuit 24 is configured to output a servo valve opening command signal h to the servo valve 12 based on the steam control valve opening command signal d and the opening feedback signal e of the steam control valve 5. The opening control circuit 24 includes a servo valve circuit subtraction unit 29, a servo amplifier unit 30, a constant generation unit 31, and a servo valve circuit addition unit 32.

[0035] The servo valve circuit subtraction unit 29 calculates the difference between the steam control valve opening command signal d output from the control valve opening command signal calculation unit 28 described above and the opening feedback signal e as an output deviation signal f. The servo valve circuit subtraction unit 29 outputs the output deviation signal f to the servo amplifier unit 30. The opening feedback signal e is transmitted from the valve opening detector 18 shown in FIG. 1. The valve opening detector 18 is configured to detect the opening of the steam control valve 5.

[0036] The servo amplifier unit 30 multiplies the output deviation signal f output from the servo valve circuit subtraction unit 29 by a servo gain to amplify the output deviation signal f. The servo amplifier unit 30 calculates and outputs the amplified output deviation signal f as a deviation amplification signal g.

[0037] The servo gain according to the present embodiment is set based on the absolute value of the output deviation signal f calculated by the servo valve circuit subtraction unit 29 as shown in FIG. 3. The servo gain when the absolute value of the output deviation signal f is equal to or less than the first reference value r1 is smaller than the servo gain when the absolute value of the output deviation signal f is equal to or greater than the second reference value r2. The second reference value r2 is larger than the first reference value r1. The servo gain is set to be a small value when the absolute value of the output deviation signal f is relatively small.

[0038] As shown in FIG. 3, the servo gain may be set to be the first servo gain when the absolute value of the output deviation signal f is less than or equal to the first reference value r1. The servo gain may be set to a constant value of the first servo gain over a range where the absolute value of the output deviation signal f is less than or equal to the first reference value r1. The servo gain may be set to be the second servo gain when the absolute value of the output deviation signal f is greater than or equal to the second reference value r2. The servo gain may be set to a constant value of the second servo gain over a range where the absolute value of the output deviation signal f is greater than or equal to the second reference value r2.

[0039] As shown in FIG. 3, the servo gain may be set to gradually increase as the absolute value of the output deviation signal f goes from the first reference value r1 to the second reference value r2. A range where the servo gain gradually increases may be set between the range less than or equal to the first reference value r1 and the range less than or equal to the second reference value r2. In this range, the servo gain increases as the absolute value of the output deviation signal f increases. As shown in FIG. 3, in this range, the servo gain may be set as a linear function of the absolute value of the output deviation signal f.

[0040] As shown in FIG. 2, the constant generation unit 31 outputs a neutral point bias compensation value for compensating the neutral point bias added during normal operation in the servo valve 12. The constant generation unit 31 transmits a signal capable of canceling the neutral point bias to the servo valve circuit addition unit 32 as a current signal corresponding to the neutral point bias compensation value.

[0041] The servo valve circuit addition unit 32 adds the above-described neutral point bias compensation value to the deviation amplification signal g output from the servo amplifier unit 30 and calculates the servo valve opening command signal h. The servo valve opening command signal h calculated by the servo valve circuit addition unit 32 is output from the opening control circuit 24 and transmitted to the servo valve 12.

[0042] Next, the operation of the present embodiment having such a configuration will be described with reference to FIG. 5. FIG. 5 shows the time change of the opening degree of the steam control valve 5. In FIG. 5, the time change of the opening degree of the steam control valve 5 when the absolute value of the output deviation signal f is large is indicated by a broken line, and the time change of the opening degree of the steam control valve 5 when the absolute value of the output deviation signal f is small is indicated by a solid line. For convenience, the opening degree before the command and the command opening degree of both are made equal.

[0043] As described above, when the servo valve opening command signal h is output from the opening control circuit 24 of the steam control valve device 20, the servo valve 12 changes its opening degree in response to this servo valve opening command signal h. As a result, the amount of the high-pressure control oil supplied to the cylinder 11b of the oil cylinder device 11 changes, and accordingly, the piston 11a of the oil cylinder device 11 moves. For this reason, the position of the valve body of the steam control valve 5 changes, and the opening degree of the steam control valve 5 reaches the opening degree corresponding to the steam control valve opening command signal d. As a result, steam is supplied to the steam turbine 3 at a flow rate corresponding to the flow rate characteristic of the steam control valve 5 shown in FIG. 4.

[0044] The case where the absolute value of the output deviation signal f, which is the difference between the steam control valve opening command signal d and the opening feedback signal e of the steam control valve 5, is large will be described. For example, as shown in FIG. 3, when the absolute value of the output deviation signal f is equal to or greater than the second reference value r2, the servo gain multiplied by the output deviation signal f in the servo amplifier unit 30 becomes the second servo gain. The second servo gain is a value larger than the first servo gain when the absolute value of the output deviation signal f is equal to or less than the first reference value r1. Based on this second servo gain, the deviation amplification signal g is calculated, and the servo valve opening command signal h is calculated.

[0045] Based on the servo valve opening command signal h, the opening of the servo valve 12 changes, and high-pressure control oil is supplied from the servo valve 12 to the cylinder 11b of the oil cylinder device 11. As a result, the change amount of the opening of the steam control valve 5 can be made larger than when the absolute value of the output deviation signal f described later is small. For this reason, as shown by the dashed line in FIG. 5, the opening of the steam control valve 5 can quickly reach the command opening corresponding to the steam control valve opening command signal d. In this case, the output deviation signal f disappears.

[0046] A case where the absolute value of the output deviation signal f, which is the difference between the steam control valve opening command signal d and the opening feedback signal e of the steam control valve 5, is small will be described. For example, as shown in FIG. 3, when the absolute value of the output deviation signal f is equal to or less than the first reference value r1, the servo gain multiplied by the output deviation signal f in the servo amplifier section 30 becomes the first servo gain. The first servo gain is a value smaller than the second servo gain when the absolute value of the output deviation signal f is equal to or greater than the second reference value r2. Based on this first servo gain, a deviation amplification signal g is calculated, and a servo valve opening command signal h is calculated.

[0047] The change amount of the opening of the servo valve 12 based on the servo valve opening command signal h is small, and the change amount of the amount of high-pressure control oil supplied from the servo valve 12 to the cylinder 11b of the oil cylinder device 11 also becomes small. For this reason, the change amount of the opening of the steam control valve 5 can be made small.

[0048] In this case, the opening degree of the steam control valve 5 does not reach the command opening degree corresponding to the steam control valve opening degree command signal d. That is, the output deviation signal f, which is the difference between the steam control valve opening degree command signal d and the opening degree feedback signal e of the steam control valve 5, remains at a small value. The first servo gain is multiplied by this output deviation signal f, and the servo valve opening degree command signal h is calculated by the servo valve circuit adder 32. In response to this servo valve opening degree command signal h, the opening degree of the servo valve 12 further changes, and the steam control valve 5 further changes its opening degree by a small change amount. In this way, the opening degree of the steam control valve 5 gradually changes toward the command opening degree. As a result, as shown by the solid line in Fig. 5, the opening degree of the steam control valve 5 slowly changes from the opening degree before the command and eventually reaches the command opening degree.

[0049] In this way, the servo valve 12 is controlled by the steam control valve control device 20 according to this embodiment. As a result, when the absolute value of the output deviation signal f is small, the movement of the piston 11a of the oil cylinder device 11 can be made slow, and the wear of the sliding parts including the piston 11a can be reduced. However, when the absolute value of the output deviation signal f is large, the movement of the piston 11a of the oil cylinder device 11 can be made rapid, and the followability to load changes can be ensured.

[0050] Note that when the opening degree of the steam control valve 5 is equal to the command opening degree, the output deviation signal f disappears. However, it is conceivable that the output deviation signal f remains without disappearing due to some electrical cause. Even in this case, the opening degree of the servo valve 12 can be slowly changed, and the wear of the sliding parts including the piston 11a can be reduced.

[0051] According to this embodiment, the servo gain is multiplied by the output deviation signal f, which is the difference between the steam control valve opening command signal d output from the flow control circuit 23 and the opening feedback signal e of the steam control valve 5. The servo gain when the absolute value of the output deviation signal f is equal to or less than the first reference value r1 is smaller than the servo gain when the absolute value of the output deviation signal f is equal to or greater than the second reference value r2. As a result, when the absolute value of the output deviation signal f is equal to or less than the first reference value r1, the change in the opening of the servo valve 12 can be slowed down, and the change in the opening of the steam control valve 5 can be slowed down. Therefore, wear of the sliding parts can be reduced, and the reliability of the sliding parts can be improved.

[0052] Further, according to this embodiment, the servo gain is set to be the first servo gain when the absolute value of the output deviation signal f is equal to or less than the first reference value r1. As a result, the change in the opening of the servo valve 12 can be stabilized, and the change in the opening of the steam control valve 5 can be stabilized.

[0053] Further, according to this embodiment, the servo gain is set to be the second servo gain when the absolute value of the output deviation signal f is equal to or greater than the second reference value r2. As a result, the change in the opening of the servo valve 12 can be stabilized, and the change in the opening of the steam control valve 5 can be stabilized.

[0054] Further, according to this embodiment, the servo gain is set to gradually increase as the absolute value of the output deviation signal f goes from the first reference value r1 to the second reference value r2. As a result, the servo gain can be continuously changed between the range where the absolute value of the output deviation signal f is equal to or less than the first reference value r1 and the range where the absolute value of the output deviation signal f is equal to or greater than the second reference value r2. Therefore, the change in the servo gain can be stabilized, and the change in the opening of the steam control valve 5 can be stabilized.

[0055] In the above-described embodiment, the servo gain is set to be the first servo gain when the absolute value of the output deviation signal f is equal to or less than the first reference value r1, and is set to be the second servo gain when the absolute value of the output deviation signal f is equal to or greater than the second reference value r2. However, the present embodiment is not limited to this. For example, the servo gain may be set such that it gradually increases as the absolute value of the output deviation signal f increases when the absolute value of the output deviation signal f is equal to or less than the first reference value r1. In this case, the servo gain may be set as a linear function of the absolute value of the output deviation signal f. Similarly, the servo gain may be set such that it gradually increases as the absolute value of the output deviation signal f increases when the absolute value of the output deviation signal f is equal to or greater than the second reference value r2. In this case, the servo gain may be set as a linear function of the absolute value of the output deviation signal f.

[0056] In the above-described embodiment, an example in which the servo gain is set based on the absolute value of the output deviation signal f calculated by the servo valve circuit subtraction unit 29 has been described. However, the present embodiment is not limited to this. For example, the servo gain may be set based on the input signal to the above-described required flow rate calculation unit 27. In this case, the servo gain when the absolute value of the input signal is equal to or less than the first reference value may be smaller than the servo gain when the absolute value of the input signal is equal to or greater than the second reference value. The second reference value is larger than the first reference value. The servo gain is set to be a small value when the absolute value of the input signal is relatively small. The input signal may be the above-described turbine speed deviation signal a3 or the above-described load deviation signal b3. Also in this case, wear of the sliding parts can be reduced and the reliability of the sliding parts can be improved.

[0057] (Second Embodiment) Next, with reference to FIG. 6, a turbine valve control device, a turbine facility, and a turbine valve drive system according to a third embodiment will be described.

[0058] In the second embodiment shown in FIG. 6, it is mainly different in that the servo gain is even smaller when the absolute value of the deviation signal is equal to or less than a third reference value that is smaller than the first reference value. Other configurations are substantially the same as those of the first embodiment shown in FIGS. 1 to 5. In FIG. 6, the same parts as those of the first embodiment shown in FIGS. 1 to 5 are denoted by the same reference numerals, and detailed description thereof is omitted.

[0059] As shown in FIG. 6, the servo gain according to the present embodiment becomes even smaller when the absolute value of the output deviation signal f is equal to or less than a third reference value r3 that is smaller than the first reference value r1. More specifically, the servo gain when the absolute value of the output deviation signal f is equal to or less than the third reference value r3 is smaller than the servo gain when the absolute value of the output deviation signal f is greater than the third reference value r3 and equal to or less than the first reference value r1.

[0060] As shown in FIG. 6, the servo gain is set to be a third servo gain when the absolute value of the output deviation signal f is equal to or less than the third reference value r3. The servo gain is set to a constant value as the third servo gain over the range where the absolute value of the output deviation signal f is equal to or less than the third reference value r3.

[0061] As shown in FIG. 6, the range in which the servo gain is set to the first servo gain may be a range where the absolute value of the output deviation signal f is equal to or greater than a fourth reference value r4 and equal to or less than the first reference value r1. The fourth reference value r4 is greater than the third reference value r3 and less than the first reference value r1.

[0062] The servo gain may be set to gradually increase as the absolute value of the output deviation signal f goes from the third reference value r3 to the fourth reference value r4. A range in which the servo gain gradually increases may be set between the range equal to or less than the third reference value r3 and the range equal to or greater than the fourth reference value r4 and equal to or less than the first reference value r1. In this range, the servo gain increases as the absolute value of the output deviation signal f increases. As shown in FIG. 6, in this range, the servo gain may be set as a linear function of the absolute value of the output deviation signal f.

[0063] Thus, according to this embodiment, when the absolute value of the output deviation signal f is equal to or less than a third reference value r3 that is smaller than the first reference value r1, the servo gain is smaller than the servo gain when the absolute value of the output deviation signal f is greater than the third reference value r3 and equal to or less than the first reference value r1. As a result, the servo gain can be changed stepwise, and the change in the servo gain can be stabilized. Therefore, the change in the opening degree of the steam control valve 5 can be stabilized. Further, since the third servo gain is smaller than the first servo gain, when the absolute value of the output deviation signal f is equal to or less than the third reference value r3, the change in the opening degree of the servo valve 12 can be made even slower. Therefore, the change in the opening degree of the steam control valve 5 can be made even slower, and the wear of the sliding parts can be further reduced.

[0064] Also, according to this embodiment, the servo gain is set to be the third servo gain when the absolute value of the output deviation signal f is equal to or less than the third reference value r3. As a result, the change in the opening degree of the servo valve 12 can be stabilized, and the change in the opening degree of the steam control valve 5 can be stabilized.

[0065] (Third Embodiment) Next, with reference to FIGS. 7 and 8, a turbine valve control device, a turbine facility, and a turbine valve drive system according to the third embodiment will be described.

[0066] In the third embodiment shown in FIGS. 7 and 8, the main difference is that a solenoid valve is provided in a control oil line connecting an oil cylinder device and a servo valve, and a first orifice is provided in a bypass line connecting the oil cylinder device and the servo valve and bypassing the solenoid valve. Other configurations are substantially the same as those of the first embodiment shown in FIGS. 1 to 5. In FIGS. 7 and 8, the same parts as those of the first embodiment shown in FIGS. 1 to 5 are denoted by the same reference numerals, and detailed descriptions thereof are omitted.

[0067] As shown in FIG. 7, the steam control valve drive system 10 according to the present embodiment further includes a control oil line 40, a solenoid valve 41, a bypass line 42, and a first orifice 43.

[0068] The control oil line 40 connects the oil cylinder device 11 and the servo valve 12. A solenoid valve 41 is provided in the control oil line 40. The solenoid valve 41 controls the supply of high-pressure control oil from the servo valve 12 to the oil cylinder device 11. The solenoid valve 41 may be a normally de-energized solenoid valve 41. When not energized, the solenoid valve 41 may be closed. When energized, the solenoid valve 41 may be open.

[0069] The bypass line 42 connects the oil cylinder device 11 and the servo valve 12. The bypass line 42 may branch from the control oil line 40 and be configured in parallel. The bypass line 42 may branch from a portion of the control oil line 40 upstream of the solenoid valve 41. The bypass line 42 may merge into a portion of the control oil line 40 downstream of the solenoid valve 41. In this way, the bypass line 42 is configured to bypass the solenoid valve 41 provided in the control oil line 40. A first orifice 43 is provided in the bypass line 42.

[0070] The control oil line 40, the solenoid valve 41, the bypass line 42, the first orifice 43, and the servo valve 12 may be configured as a steam control valve drive device 50. The steam control valve drive device 50 may be configured as one block body.

[0071] The solenoid valve 41 is controlled by the steam control valve control device 20 described above. The solenoid valve 41 may be closed when the absolute value of the output deviation signal f calculated by the servo valve circuit subtraction unit 29 of the opening control circuit 24 is small, and opened when it is large. More specifically, the steam control valve control device 20 may control the solenoid valve 41 to close when the absolute value of the output deviation signal f is less than or equal to the first reference value r1, and to open when the absolute value of the output deviation signal f is greater than or equal to the second reference value r2. In this case, when the absolute value of the output deviation signal f is less than or equal to the first reference value r1 shown in FIG. 3, the solenoid valve 41 is closed, and when it is greater than or equal to the second reference value r2, the solenoid valve 41 is open.

[0072] When the absolute value of the output deviation signal f is small, when the solenoid valve 41 closes, the high-pressure control oil supplied from the servo valve 12 to the cylinder 11b of the oil cylinder device 11 passes through the first orifice 43 provided in the bypass line 42. As a result, the supply of high-pressure control oil to the cylinder 11b can be slowed down, and the movement of the piston 11a of the oil cylinder device 11 can be made slower. Therefore, the opening degree of the steam control valve 5 can be changed slowly, and the wear of the sliding parts including the piston 11a can be reduced.

[0073] On the other hand, when the absolute value of the output deviation signal f is large, when the solenoid valve 41 opens, the high-pressure control oil supplied from the servo valve 12 to the cylinder 11b of the oil cylinder device 11 mainly passes through the solenoid valve 41 provided in the control oil line 40. As a result, high-pressure control oil can be quickly supplied to the cylinder 11b, and the movement of the piston 11a of the oil cylinder device 11 can be made faster. Therefore, the opening degree of the steam control valve 5 can be changed quickly, and the followability to load changes can be ensured.

[0074] According to this embodiment, the control oil line 40 connecting the servo valve 12 and the cylinder 11b of the oil cylinder device 11 is provided with a solenoid valve 41. The solenoid valve 41 closes when the absolute value of the output deviation signal f is less than or equal to the first reference value r1, and opens when the absolute value of the output deviation signal f is greater than or equal to the second reference value r2 which is greater than the first reference value r1. By this, when the absolute value of the output deviation signal f is less than or equal to the first reference value r1, the change in the high-pressure control oil supplied to the cylinder 11b of the oil cylinder device 11 can be slowed down, and the change in the opening degree of the steam control valve 5 can be slowed down. Therefore, the wear of the sliding parts can be reduced, and the reliability of the sliding parts can be improved.

[0075] In addition, in the above-described embodiment, as shown in FIG. 8, a second orifice 44 may be provided in the control oil line 40. The second orifice 44 is arranged at a position bypassing the first orifice 43. For example, as shown in FIG. 8, the second orifice 44 may be arranged between the branch point of the control oil line 40 and the bypass line 42 and the solenoid valve 41. Alternatively, although not shown, the second orifice 44 may be arranged between the confluence point of the solenoid valve 41 and the bypass line 42 in the control oil line 40.

[0076] When the solenoid valve 41 is open, the high-pressure control oil mainly passes through the second orifice 44 and the solenoid valve 41. Therefore, it is possible to suppress a rapid change in the amount of the high-pressure control oil from the servo valve 12 to the cylinder 11b of the oil cylinder device 11. Therefore, hunting of the high-pressure control oil can be suppressed, and the opening degree of the steam control valve 5 can be stabilized. Note that, in order to suppress hunting, the magnitude of the absolute value of the output deviation signal f when switching the solenoid valve 41 from non-excitation to excitation and the magnitude of the absolute value of the output deviation signal f when switching the solenoid valve 41 from excitation to non-excitation may be different from each other.

[0077] On the one hand, the flow path cross-sectional area of the second orifice 44 is larger than that of the first orifice 43. This can prevent the change in the amount of high-pressure control oil flowing into the cylinder 11b when the solenoid valve 41 is open from becoming slower than the change in the amount of high-pressure control oil when the solenoid valve 41 is closed.

[0078] Also, in the above-described embodiment, an example has been described in which the steam control valve control device 20 controls the solenoid valve 41 to close when the absolute value of the output deviation signal f is less than or equal to the first reference value r1 and to open when the absolute value of the output deviation signal f is greater than or equal to the second reference value r2. However, the present embodiment is not limited to this. For example, the steam control valve control device 20 may control the solenoid valve 41 based on the input signal to the above-described required flow rate calculation unit 27. In this case, the steam control valve control device 20 may control the solenoid valve 41 to close when the absolute value of the input signal is less than or equal to the first reference value and to open when the absolute value of the input signal is greater than or equal to the second reference value. The second reference value is greater than the first reference value. The input signal may be the above-described turbine speed deviation signal a3 or the above-described load deviation signal b3.

[0079] Also, in the above-described embodiment, the servo valve 12 shown in FIG. 7 may be controlled by the steam control valve control device 20 shown in FIG. 2. When the absolute value of the output deviation signal f is greater than or equal to the first reference value r1, the change in the opening degree of the steam control valve 5 can be slowed down by the slow change in the opening degree of the servo valve 12 under the control of the steam control valve control device 20. At this time, by passing the high-pressure control oil through the first orifice 43, the change in the high-pressure control oil supplied to the cylinder 11b of the oil cylinder device 11 can be made even slower. Therefore, the change in the opening degree of the steam control valve 5 can be made even slower, and the wear of the sliding parts can be further reduced.

[0080] According to the above-described embodiment, the wear of the sliding parts can be reduced.

[0081] Although several embodiments of the present invention have been described, these embodiments are presented by way of example and are not intended to limit the scope of the invention. These novel embodiments can be implemented in various other forms, and various omissions, replacements, and changes can be made without departing from the gist of the invention. These embodiments and their modifications are included in the scope and gist of the invention, and are included in the invention described in the claims and its equivalent scope. Also, of course, within the scope of the gist of the present invention, it is also possible to appropriately combine these embodiments partially.

Explanation of Reference Numerals

[0082] 3: Steam turbine, 5: Steam control valve, 10: Steam control valve drive system, 11: Oil cylinder device, 12: Servo valve, 20: Steam control valve control device, 23: Flow control circuit, 24: Opening control circuit, 29: Servo valve circuit subtraction unit, 30: Servo amplifier unit, 40: Control oil line, 41: Solenoid valve, 42: Bypass line, 43: First orifice, 44: Second orifice, r1: First reference value, r2: Second reference value, r3: Third reference value, a1: Turbine speed signal, a3: Turbine speed deviation signal, b1: Load signal, b3: Load deviation signal, d: Steam control valve opening command signal, e: Opening feedback signal, f: Output deviation signal, g: Deviation amplification signal, h: Servo valve opening command signal

Claims

1. A turbine valve control device for controlling a servo valve for controlling the opening degree of a turbine flow control valve that adjusts the flow rate of the working fluid supplied to a power generation turbine using high-pressure control oil, a flow control circuit that outputs a control valve opening degree command signal for the turbine flow control valve based on a turbine speed signal or a load signal, an opening degree control circuit that outputs a servo valve opening degree command signal to the servo valve based on the control valve opening degree command signal and the opening degree feedback signal of the turbine flow control valve, comprising: the opening degree control circuit includes: a servo valve circuit subtraction unit that calculates the difference between the control valve opening degree command signal and the opening degree feedback signal as an output deviation signal; a servo amplification unit that calculates a deviation amplification signal by multiplying the output deviation signal by a servo gain set based on the output deviation signal; wherein, when the absolute value of the output deviation signal is equal to or less than a first reference value, the servo gain is smaller than the servo gain when the absolute value of the output deviation signal is equal to or greater than a second reference value that is larger than the first reference value, a turbine valve control device.

2. The servo gain is set to be a first servo gain when the absolute value of the output deviation signal is equal to or less than the first reference value, The turbine valve control device according to claim 1.

3. The servo gain is set to be a second servo gain when the absolute value of the output deviation signal is equal to or greater than the second reference value, The turbine valve control device according to claim 1 or 2.

4. The servo gain is set to gradually increase as the absolute value of the output deviation signal goes from the first reference value to the second reference value, The turbine valve control device according to claim 1 or 2.

5. When the absolute value of the output deviation signal is equal to or less than a third reference value that is smaller than the first reference value, the servo gain is smaller than the servo gain when the absolute value of the output deviation signal is greater than the third reference value and equal to or less than the first reference value, The turbine valve control device according to claim 1 or 2.

6. The servo gain is set to be a third servo gain when the absolute value of the output deviation signal is equal to or less than the third reference value, The turbine valve control device according to claim 5.

7. A turbine valve control device for controlling the opening degree of a turbine flow control valve that adjusts the flow rate of the working fluid supplied to a power generation turbine by using high-pressure control oil, an input deviation calculation circuit that calculates the difference between a turbine speed signal or a load signal and a corresponding required signal as an input deviation signal, a flow control circuit that outputs a control valve opening degree command signal for the turbine flow control valve by using the input deviation signal, an opening degree control circuit that outputs a servo valve opening degree command signal to the servo valve based on the control valve opening degree command signal and the opening degree feedback signal of the turbine flow control valve, comprising: the opening degree control circuit includes: a servo valve circuit subtraction unit that calculates the difference between the control valve opening degree command signal and the opening degree feedback signal as an output deviation signal, a servo amplification unit that calculates a deviation amplification signal by multiplying the output deviation signal by a servo gain set based on the input deviation signal, including: when the absolute value of the input deviation signal is equal to or less than a first reference value, the servo gain is smaller than the servo gain when the absolute value of the input deviation signal is equal to or greater than a second reference value greater than the first reference value, a turbine valve control device.

8. a power generation turbine, a turbine flow control valve that adjusts the flow rate of the working fluid supplied to the power generation turbine, a servo valve that controls the opening degree of the turbine flow control valve by using high-pressure control oil, the turbine valve control device according to claim 1 or 7, a turbine facility comprising:

9. a turbine valve drive system that drives a turbine flow control valve that adjusts the flow rate of the working fluid supplied to a power generation turbine, an oil cylinder device that drives the turbine flow control valve, a servo valve that adjusts the amount of high-pressure control oil supplied to the oil cylinder device, a control oil line connecting the oil cylinder device and the servo valve, a solenoid valve provided in the control oil line, a bypass line connecting the oil cylinder device and the servo valve and bypassing the solenoid valve, a first orifice provided in the bypass line, a turbine valve control device, comprising: the turbine valve control device includes: a flow control circuit that outputs a control valve opening degree command signal for the turbine flow control valve based on a turbine speed signal or a load signal, an opening degree control circuit that outputs a servo valve opening degree command signal to the servo valve based on the control valve opening degree command signal and the opening degree feedback signal of the turbine flow control valve, comprising: The opening control circuit includes a servo valve circuit subtraction unit that calculates the difference between the control valve opening command signal and the opening feedback signal as an output deviation signal, and the turbine valve control device controls the electromagnetic valve to close when the absolute value of the output deviation signal is equal to or less than a first reference value and to open when the absolute value of the output deviation signal is equal to or greater than a second reference value that is greater than the first reference value. Turbine valve drive system.

10. A turbine valve drive system for driving a turbine flow control valve that adjusts the flow rate of the working fluid supplied to a power generation turbine, including an oil cylinder device that drives the turbine flow control valve, a servo valve that adjusts the amount of high-pressure control oil supplied to the oil cylinder device, a control oil line connecting the oil cylinder device and the servo valve, an electromagnetic valve provided in the control oil line, a bypass line that connects the oil cylinder device and the servo valve and bypasses the electromagnetic valve, a first orifice provided in the bypass line, and a turbine valve control device, wherein the turbine valve control device includes an input deviation calculation circuit that calculates the difference between a turbine speed signal or a load signal and a corresponding required signal as an input deviation signal, a flow control circuit that outputs a control valve opening command signal for the turbine flow control valve using the input deviation signal, and an opening control circuit that outputs a servo valve opening command signal to the servo valve based on the control valve opening command signal and the opening feedback signal of the turbine flow control valve, and the turbine valve control device controls the electromagnetic valve to close when the absolute value of the input deviation signal is equal to or less than a first reference value and to open when the absolute value of the input deviation signal is equal to or greater than a second reference value that is greater than the first reference value. Turbine valve drive system.

11. A second orifice is provided at a position in the control oil line that bypasses the first orifice, and the flow passage cross-sectional area of the second orifice is larger than the flow passage cross-sectional area of the first orifice. The turbine valve drive system according to claim 9 or 10. ​ ​

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