JP2021113510A - Steam turbine control device and steam turbine power generation equipment - Google Patents

Abstract

To suppress a sensitive change of an opening of a steam regulating valve, and to make a rotation number of a steam turbine smoothly converged to a target rotation number, or its vicinity.SOLUTION: In a steam turbine control device 10 for controlling a steam regulating valve 4 so that a rotation number deviation X being a difference between a measurement rotation number Xm of a steam turbine 2 and a preset target rotation number Xt becomes small, the target rotation number Xt, choices which are preset in a plurality of pieces at each value of the rotation number deviation X on the basis of an operation amount of the steam regulating valve 4, and a limit change rate R which is preset with respect to a change of a speed adjustment rate are stored in the control device in advance. A speed adjustment rate function is defined by using the operation amount which is selected at each value of the rotation number deviation X, an opening of the steam regulating valve 4 is controlled according to the rotation number deviation X under the defined speed adjustment rated function, and when the selection of the operation amount is changed, the speed adjustment rate function is transited at the limit change rate R.SELECTED DRAWING: Figure 1

Description

The present invention relates to a steam turbine control device and a steam turbine power generation facility.

Generally, a steam turbine is driven by steam supplied through a steam control valve. In a steam turbine power generation facility in which a generator is driven by a steam turbine, a function of the speed adjustment rate (hereinafter referred to as speed) is obtained with respect to the rotation speed deviation between the measured rotation speed (actual rotation speed) and the target rotation speed (for example, the rated rotation speed) of the steam turbine. The adjustment rate function) may be set (see Patent Document 1 and the like).

In such a steam turbine power generation facility, the opening degree of the steam control valve is controlled according to the rotation speed deviation under the speed adjustment rate function while the generator is paralleled (joined) in the power system (for example, a commercial power system). Will be done. For example, if the measured rotation speed of the steam turbine is lower than the target rotation speed, the steam control valve is opened by a ratio corresponding to the magnitude of the rotation speed deviation from the current opening, and the supply flow rate of the working fluid is increased to increase the supply flow rate of the working fluid. Increase the number of revolutions of. On the contrary, if the measured rotation speed of the steam turbine is higher than the target rotation speed, the steam control valve is closed by a ratio corresponding to the magnitude of the rotation speed deviation from the current opening, and the supply flow rate of the working fluid is reduced to steam. Reduce the turbine speed. By such feedback control, the rotation speed of the steam turbine is converged to the target rotation speed, and the system frequency is stabilized.

Japanese Unexamined Patent Publication No. 3-92505

In recent years, power generation facilities that use natural energy such as wind power and solar power are increasingly connected to the power system, and the proportion of such power generation facilities in the power system is also increasing. However, the output of power generation equipment that uses such natural energy tends to fluctuate depending on the season, time, weather conditions, etc., which is one of the causes of unstable system frequency. Such fluctuations in the system frequency can fluctuate the rotation speed of the steam turbine and destabilize the power generation output in the steam turbine power generation facility in which the generator is arranged in parallel with the power system.

At this time, when the opening degree of the steam control valve and the rotation speed deviation are set in a simple proportional relationship, when the rotation speed of the steam turbine changes abruptly, the opening degree of the steam control valve also changes abruptly. For example, if the system frequency suddenly changes while the rotation speed of the steam turbine is settled near the target rotation speed, the rotation speed of the steam turbine may decrease sharply under the influence of the sudden change. In this case, the flow rate of steam supplied to the steam turbine suddenly increases more than necessary, hunting may occur, and the rotation speed of the steam turbine may become unstable.

An object of the present invention is to provide a steam turbine control device and a steam turbine power generation facility capable of suppressing a sensitive change in the opening degree of a steam control valve and smoothly converging the rotation speed of the steam turbine to or near the target rotation speed. To do.

In order to achieve the above object, the present invention comprises a boiler that generates steam, a steam turbine driven by steam supplied from the boiler, a generator driven by the steam turbine, and the steam from the boiler. It is provided in a steam turbine power generation facility equipped with a steam control valve that adjusts the flow rate of steam supplied to the turbine, and the rotation speed deviation, which is the difference between the measured rotation speed of the steam turbine and the preset target rotation speed, becomes small. The steam turbine control device that controls the steam control valve is configured to include a storage device and a calculation device, and the storage device has a target rotation speed of the steam turbine and an operating amount of the steam control valve. A plurality of preset options for each rotation speed deviation value and a preset limit change rate for a change in the speed adjustment rate are stored, and the calculation device stores each of the rotation speed deviation values. A speed regulation rate function is defined by the selected operation amount, the opening degree of the steam control valve is controlled according to the rotation speed deviation under the defined speed adjustment rate function, and the individual rotation speed deviations are individually controlled. When the selection of the operation amount is changed for at least one of the values, the current speed adjustment rate function is configured to transition to the changed speed adjustment rate function at the limit change rate. ..

According to the present invention, it is possible to suppress a sensitive change in the opening degree of the steam control valve and smoothly converge the rotation speed of the steam turbine to or near the target rotation speed.

Schematic diagram showing the configuration of the turbine control device according to the embodiment of the present invention. A graph showing the speed adjustment rate function (basic function) of a steam turbine defined by the relationship between the rotation speed deviation and the operating amount of the steam control valve. A graph showing the speed adjustment rate function (adjusted function) of the steam turbine defined by the relationship between the rotation speed deviation and the operating amount of the steam control valve. A flowchart showing a speed adjustment rate switching operation by the steam turbine control device according to the embodiment of the present invention. Waveform diagram showing an example of how the speed adjustment rate and the like transition with the switching operation of FIG.

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

− Configuration −
FIG. 1 is a schematic view showing a configuration of a steam turbine power generation facility according to an embodiment of the present invention. The steam turbine power generation facility shown in the figure includes a boiler 1, a steam turbine 2, a generator 3, a steam control valve 4, and a steam turbine control device 10.

The boiler 1 heats the water supplied by the water supply pump (not shown) to generate steam, which is supplied to the steam turbine 2. Although the heat source of the boiler 1 is not shown, typical examples of the heat source of the boiler 1 are, for example, exhaust gas of a gas turbine, heat of combustion of fuel, a reactor, and the like.

The steam turbine 2 is driven by the steam supplied from the boiler 1. The steam that drives the steam turbine 2 is guided by a condenser (not shown) and returned to water, and is supplied to the boiler 1 again by a water supply pump (not shown).

The rotor of the generator 3 is coaxially connected to the rotor of the steam turbine 2. The generator 3 is driven by the rotational power of the steam turbine 2 to generate electricity. The generator 3 is connected to an electric power system (for example, a commercial electric power system). In addition to the steam turbine power generation equipment shown in FIG. 1, at least one other power generation equipment (not shown) is connected to the power system. Other power generation facilities connected to the power grid may include power generation facilities that generate electricity from natural energy (renewable energy) such as wind power and solar power.

The steam control valve 4 is an electromagnetically driven valve, and adjusts the flow rate of steam supplied from the boiler 1 to the steam turbine 2. The basic opening degree of the steam control valve 4 is an intermediate opening degree (for example, 50% opening degree). When the opening degree of the steam control valve 4 increases, the flow rate of steam supplied to the steam turbine 2 increases, and the output of the steam turbine 2 and thus the amount of power generated by the generator 3 increase. On the contrary, when the opening degree of the steam control valve 4 decreases, the flow rate of steam supplied to the steam turbine 2 decreases, and the output of the steam turbine 2 and thus the amount of power generated by the generator 3 decrease.

The steam turbine power generation facility is provided with a rotation speed sensor 5 that measures the rotation speed of the steam turbine 2. The measured rotation speed Xm of the steam turbine 2 measured by the rotation speed sensor 5 is input to the rotation speed deviation calculation circuit 13 of the steam turbine control device 10.

The steam turbine control device 10 is a computer, and includes a memory (storage device) 11, a CPU (arithmetic unit) 12, a timer (not shown), and the like. The steam turbine control device 10 sets the steam control valve 4 so that the rotation speed deviation X (= Xm-Xt), which is the difference between the measured rotation speed Xm of the steam turbine 2 and the preset target rotation speed Xt, becomes small. It has a function to control. In particular, in the steam turbine control device 10 of the present embodiment, the speed adjustment rate function is defined by the operating amount (correction amount) of the steam control valve 4 selected for each value of the rotation speed deviation X as described later, and the defined speed. It is configured to control the opening degree of the steam control valve 4 according to the rotation speed deviation X under the adjustment rate function. The steam control valve 4 is controlled by the steam turbine control device 10 according to the rotation speed deviation X, and the rotation speed of the steam turbine 2 converges to or near the target rotation speed Xt. Whether the rotation speed of the steam turbine 2 converges to the target rotation speed Xt or converges to the target rotation speed Xt or its vicinity is designed by the speed adjustment rate function as will be described later in FIGS. 2 and 3. It depends on what is done.

As an example of the target rotation speed Xt, the rated rotation speed can be mentioned. The rated rotation speed is the rotation speed of the steam turbine 2 under the operating conditions of the steam turbine 2 specified by the manufacturer.

In the memory 11 of the steam turbine control device 10, in addition to the program related to the control of the steam control valve 4, data necessary for executing the program is stored. The program and data stored in the memory 11 are read into the CPU 12, and the steam control valve 4 is controlled by the CPU 12 according to the value of the rotation speed deviation X. The data stored in the memory 11 includes a plurality of preset options (described later) for each value of the rotation speed deviation X with respect to the operation amount Y of the steam control valve 4. Here, in the present embodiment, each value of the rotation speed deviation X is appropriately represented as Xn (n = natural number). The difference between Xn and Xn-1 can be the minimum difference between the two values of the rotation speed that can be identified according to the resolution of the rotation speed sensor 5, but in this example, it is larger than that and is arbitrarily set. do. That is, each value Xn of the rotation speed deviation X is an arbitrarily set constant. For each value Xn of the rotation speed deviation X, a plurality of options Yn1 and Yn2 of two manipulated variables Y are set in association with each other. The memory 11 stores individual values Xn of these rotation speed deviations X, and a plurality of options Yn1 and Yn2 of the manipulated variable Y set for each value Xn. The value of the manipulated variable Y for each value Xn of the rotation speed deviation X can be arbitrarily selected by the operator from the options Yn1 and Yn2 by the input device 20. The input device 20 is a user interface for inputting a speed adjustment rate switching signal Ss (described later) or the like to the steam turbine control device 10.

In addition to the manipulated variable Y, the memory 11 also stores data such as a target rotation speed Xt of the steam turbine 2 and a preset limit change rate R for changes in the speed adjustment rate of the steam turbine 2. The limit change rate R is the amount of change in the manipulated variable Y per unit time when the value of the manipulated variable Y that defines the speed adjustment rate for a certain value Xn with the rotation speed deviation X is changed from one value to another. It is a value specified for. That is, in the present embodiment, when the selection of the manipulated variable Y is changed from the first option Yn1 to the second option Yn2 for a certain rotation speed deviation Xn, the first option Yn1 is changed to the second option Yn2 at a constant rate in time. The value of the manipulated variable Y changes. At the same time as the switching operation, the value of the operation amount Y does not switch to the second option Yn2 discretely in time, but the operation amount Y begins to change by the switching operation and gradually changes from the first option Yn1 to the second option Yn2. It transitions and switches over time.

The CPU 12 includes a rotation speed deviation calculation circuit 13, a speed adjustment rate switching circuit 14, an operation amount calculation circuit 15, and an opening command value calculation circuit 16. The speed adjustment rate switching circuit 14 is further configured to include a selection circuit 17 and a rate of change limiting circuit 18. In other words, the CPU 12 constitutes a rotation speed deviation calculation circuit 13, a speed adjustment rate switching circuit 14, an operation amount calculation circuit 15, and an opening command value calculation circuit 16, and executes the functions of each circuit according to a program.

The rotation speed deviation calculation circuit 13 calculates the rotation speed deviation X (= Xm-Xt), which is the difference between the measured rotation speed Xm measured by the rotation speed sensor 5 and the target rotation speed Xt stored in the memory 11. Output to the operation amount calculation circuit 15.

The speed adjustment rate switching circuit 14 determines the operation amount Y for each value Xn of the rotation speed deviation X by the selection circuit 17 based on the speed adjustment rate switching signal Ss input from the input device 20 in response to the switching operation of the operator. The value is selected from the options Yn1 and Yn2 and output to the rate of change limiting circuit 18. The speed adjustment rate switching signal Ss is, for example, a signal including ON / OFF data for each value Xn of the rotation speed deviation X. For example, the rotation speed deviation X1 will be focused on. For example, when the setting of the rotation speed deviation X1 in the speed adjustment rate switching signal Ss is ON, the selection circuit 17 selects the first option Y11 as the manipulated variable Y corresponding to the rotation speed deviation X1. Then, the data (X1, Y11) that defines the speed adjustment rate function for the rotation speed deviation X1 is output from the selection circuit 17 to the change rate limiting circuit 18. On the contrary, when the setting of the rotation speed deviation X1 in the speed adjustment rate switching signal Ss is OFF, the second option Y12 is selected as the operation amount Y corresponding to the rotation speed deviation X1. Then, the data (X1, Y12) that defines the speed adjustment rate function for the rotation speed deviation X1 is output from the selection circuit 17 to the change rate limiting circuit 18.

The speed adjustment rate switching circuit 14 also adds the data of the limit change rate R stored in the memory 11 to the data output from the selection circuit 17 by the change rate limiting circuit 18 and outputs the data to the manipulated variable calculation circuit 15.

The manipulated variable calculation circuit 15 generates a speed adjustment rate function based on the data input from the speed adjustment rate switching circuit 14, and adjusts the steam according to the current rotation speed deviation X calculated by the rotation speed deviation calculation circuit 13. The operation amount Y of the valve 4 is calculated and output to the opening command value calculation circuit 16. At this time, when the selection of the manipulated variable Y is changed for at least one of the individual values Xn of the rotation speed deviation X, the speed adjustment rate function is limited and changed from the current speed adjustment rate function to the changed speed adjustment rate function. Transition at a rate R. For example, suppose that the limit change rate R defines the change amount of the manipulated variable Y per unit time t as k (%), and the value of the manipulated variable Y is changed from Yn1 to Yn2 for the rotation speed deviation X1. .. In this case, with respect to the manipulated variable Y corresponding to the rotation speed deviation X1, the value output after the time t is (Yn1 + k), the value output after the time 2t is (Yn1 + 2k), and the value of the manipulated variable Y gradually changes. To go. If there is a difference of 10 k (%) between the manipulated quantities Yn1 and Yn2, it takes 10 tons from the start to the completion of switching the value of the manipulated variable Y for the rotation speed deviation X1.

The opening command value calculation circuit 16 adds the operation amount Y input from the operation amount calculation circuit 15 to the basic value Sv0 of the opening command of the steam control valve 4, and uses this as the opening command value Sv for the steam control valve 4 Output to. As a result, the opening degree of the steam control valve 4 is controlled to the opening degree command value Sv. The basic value Sv0 of the opening command was calculated according to the load command S1 input to the steam turbine control device 10 from the upper control device (not shown) according to, for example, the required power generation amount from the central power supply command center. This is the opening degree of the steam control valve 4. This basic value Sv0 is a value calculated based on the specifications of the steam turbine power generation facility without taking into account the measured rotation speed Xm, and is a constant value if the required power generation amount is constant.

2 and 3 are graphs showing the speed adjustment rate function (control characteristics of the steam control valve) of the steam turbine defined by the relationship between the rotation speed deviation and the operation amount of the steam control valve, and FIG. 2 shows the basic function. FIG. 3 illustrates the adjusted function. In the graphs of FIGS. 2 and 3, the horizontal axis represents the rotation speed deviation X (rpm), and the vertical axis represents the operation amount Y (%) of the steam control valve 4. The graphs shown in FIGS. 2 and 3 correspond to a diagram of an example of the speed adjustment rate function generated by the manipulated variable calculation circuit 15.

In the present embodiment, the positive and negative values of the rotation speed deviation X (= Xm-Xt) are distinguished, and the value of X> 0 when Xm> Xt, X = 0 when Xm = Xt, and X <0 when Xm <Xt. Take. X1 and X2 illustrated in FIGS. 2 and 3 are negative values, and X3 and Xa are positive values. a is one of the values of n.

In the present embodiment, a different value is set for each of the individual values Xn of the rotation speed deviation X in the first option Yn1 of the manipulated variable Y. When the first option Yn1 is selected for all the values Xn of the rotation speed deviation X, the basic function of the speed adjustment rate shown in FIG. 2 is defined. Under this basic function, the manipulated variable Y decreases in proportion to the rotation speed deviation X through the origin (0,0). That is, if the rotation speed deviation X> 0, the operation amount Y increases in the valve closing direction in proportion to the magnitude (absolute value) of the rotation speed deviation X, and the opening degree of the steam control valve 4 becomes the current value. On the other hand, it decreases by the magnitude (absolute value) of the manipulated variable Y. On the contrary, when the rotation speed deviation X <0, the operation amount Y increases in the valve opening direction in proportion to the magnitude (absolute value) of the rotation speed deviation X, and the opening degree of the steam control valve 4 becomes the current value. On the other hand, it increases by the magnitude (absolute value) of the manipulated variable Y. When the rotation speed deviation X = 0, the operation amount Y is 0 (zero), so that the opening degree of the steam control valve 4 is maintained at the current value. Therefore, the rotation speed of the steam turbine 2 is feedback-controlled so as to converge to the target rotation speed Xt.

On the other hand, the second option Yn2 is set to 0 (zero). The graph of FIG. 3 shows an example in which the selection of the manipulated variable Y of the rotation speed deviations X2 and X3 is changed to the second options Y22 and Y32 (= 0) from the basic function of FIG. According to the adjusted speed adjustment rate function illustrated in FIG. 3, even if the rotation speed deviation X fluctuates between X2-X3, the operation amount Y of the steam control valve 4 becomes 0, and the current state of the steam control valve 4 The opening is maintained. In the example of FIG. 3, the rotation speed of the steam turbine 2 is set so that the rotation speed deviation X falls within the range of X2-X3 in which the second option Yn2 is selected, that is, the rotation speed at or near the target rotation speed Xt. Feedback control is performed so as to converge.

-Operation-
FIG. 4 is a flowchart showing the switching operation of the speed adjustment rate by the steam turbine control device. FIG. 5 is a waveform diagram showing an example of how the speed adjustment rate and the like transition with the switching operation of FIG. The vertical axis of each waveform diagram shown in FIG. 5 indicates the magnitude of each parameter, and the horizontal axis is a common time axis. Here, a case where the speed adjustment rate function is switched from the function shown in FIG. 2 to the function shown in FIG. 3 will be described as an example. Further, in order to facilitate understanding, a state in which the rotation speed deviation X is constant at X2 will be described as an example, but in reality, the measurement rotation is performed by controlling the opening degree of the steam control valve 4 based on the speed adjustment rate function. The number Xm is controlled and converges to or near the target rotation speed Xt.

・ START
First, with the speed adjustment rate function defined as shown in FIG. 2, the speed adjustment rate switching signal Ss for switching to the speed adjustment rate function as shown in FIG. 3 is input to the steam turbine control device 10 at time T0 shown in FIG. Suppose it was done. As a result, the steam turbine controller 10 starts executing the procedure of FIG. 4 at time T0. The speed adjustment rate switching signal Ss that defines the speed adjustment rate in FIG. 3 includes, for example, information of {(X1, X2, X3, ... Xa) = (ON, OFF, OFF, ... ON)}.

-Step S101
When the procedure of FIG. 4 is started, the steam turbine control device 10 selects one of the manipulated quantities Yn1 and Yn2 for each rotation speed deviation Xn based on the speed adjustment rate switching signal Ss in the selection circuit 17 as step S101. The data is output to the rate of change limiting circuit 18. Here, the data input to the rate of change limiting circuit 18 is {(X1, Y11), (X2, Y22), (X3, Y32), ... (Xa, Ya1)}.

-Step S102
When the procedure is moved to step S102, the steam turbine control device 10 outputs the limit change rate R (= k / t) to the manipulated variable calculation circuit 15 together with the data generated by the selection circuit 17.

-Step S103-END
In the following steps S103 and S104, the steam turbine control device 10 limits the speed adjustment rate function from the function of FIG. 2 to the function of FIG. 3 by the manipulated variable calculation circuit 15 based on the data input from the rate of change limiting circuit 18. The transition is made at the rate of change R. For example, after the time t at time T0, a speed adjustment rate function is generated based on the data {(X1, Y11), (X2, Y22-k), (X3, Y32 + k), ... (Xa, Ya1)} (step S103). ). Then, it is determined whether the speed adjustment rate function after the time t matches the function of FIG. 3 (step S104). In this determination, the consistency with the data {(X1, Y11), (X2, Y22), (X3, Y32), ... (Xa, Ya1)} of the speed adjustment rate function of FIG. 3 is determined. If the determination in step S104 is not satisfied, the steam turbine controller 10 returns the procedure to step S103. Then, the steam turbine control device 10 further after the time t (after the time 2t at the time T0), the data {(X1, Y11), (X2, Y22-2k), (X3, Y32 + 2k), ... (Xa, Ya1)} The speed adjustment rate function based on the above is generated, and the determination in step S104 is executed again.

As a result, the manipulated variable Y of the rotation speed deviation X2 decreases from Y21 by k per time t, that is, to Y22 at the limit change rate R. Similarly, the manipulated variable Y of the rotation speed deviation X3 increases from Y31 to Y32 by k per hour t. If there is a difference of 10k between Y21 and Y22, the procedure of steps S103 and S104 is repeated 10 times, and after a time of 10t (= time T1), the transition of the manipulated variable Y for the rotation speed deviation X2 is completed (FIG. 5). .. At that time, for example, if the difference between Y31 and Y32 is larger than 10k and the transition of the manipulated variable Y for the rotation speed deviation X3 is not completed yet, the procedure of step S103 is repeated until the determination of step S104 is satisfied. On the contrary, if the difference between Y31 and Y32 is 10 k or less and the transition of the manipulated variable Y for the rotational speed deviation X3 is already completed when the transition of the manipulated variable Y for the rotational speed deviation X2 is completed, the switching of the speed adjustment rate is completed. Then, the steam turbine control device 10 ends the flow shown in FIG.

In this example, the rotation speed deviation X = X2. When switching the speed adjustment rate function to the function of FIG. 3, as shown in FIG. 5, the manipulated variable Y of the rotation speed deviation X2 transitions from Y21 to Y22 from time T0 to T1. Therefore, from time T0 to T1, the opening command value Sv of the steam control valve 4 is calculated based on the speed adjustment rate during the transition. As a result, from time T0 to T1, even if the rotation speed deviation X is constant at X2, the opening command value Sv linearly decreases by the difference between the manipulated quantities Y21 and Y22 over time 10t (FIG. 5). ..

-Effect-
Generally, in a steam turbine power generation facility, as shown in FIG. 2, a speed adjustment rate function is defined in which the rotation speed deviation and the opening degree of the steam control valve are defined as a simple proportional relationship. Depending on the steam turbine power generation facility, and in some cases, the speed regulation rate function as shown in FIG. 2 may be appropriate. However, there is a tendency for the rotation speed deviation to occur for each steam turbine power generation facility, time, season, etc., and for the rotation speed deviation in a specific range (for example, about 30% before and after the target rotation speed), the steam control valve is opened. Even if the degree is not corrected, it may immediately turn to the suppression direction. Regarding the rotation speed deviation that can be settled naturally without correcting the opening degree of the steam control valve, if the opening degree of the steam control valve changes sensitively, for example, hunting occurs and the rotation speed of the steam turbine is targeted. It may take some time to converge to the number of revolutions or its vicinity.

On the other hand, in the present embodiment, the speed adjustment rate can be designed by selecting the value of the manipulated variable Y from a plurality of options Yn1 and Yn2 prepared for each individual value Xn of the rotation speed deviation X. For example, if a specific range of rotation speed deviation X, which is not preferable when the opening degree of the steam control valve changes sensitively, is found from the past operation record data of the steam turbine power generation facility, the rotation speed deviation Xn in that range is selected as options Yn1, Select the smaller absolute value of Yn2. As a result, it is possible to suppress the valve opening degree from changing more than necessary while the rotation speed deviation X is changing in a specific range. In particular, in the present embodiment, since the second option Yn2 of the manipulated variable Y is set to 0 for each rotation speed deviation Xn, a kind of dead zone can be secured by selecting the second option Yn2 in a specific range. In this case, the opening degree of the steam control valve 4 can be maintained as long as the rotation speed deviation X changes within a specific range.

Further, for example, when the selection of the operation amount Y is changed for the rotation speed deviation Xn in a specific range, it is assumed that the rotation speed deviation Xn matches the current rotation speed deviation. In such a case, if the speed adjustment rate switching signal Ss is input and the speed adjustment rate function is discretely switched from the function of FIG. 2 to the function of FIG. 3, for example, the manipulated variable Y changes from Yn1 to Yn2. The opening degree of the steam control valve 4 suddenly changes.

With respect to this point, in the present embodiment, the speed adjustment rate function is changed at the limit change rate R and switched over time. As a result, even if the selection of the operation amount Y is changed with respect to the rotation speed deviation occurring in the current steam turbine 2 as described above with reference to FIG. 5, it is possible to suppress a sudden change in the opening degree of the steam control valve 4. ..

As described above, according to the present embodiment, it is possible to suppress a sensitive change in the opening degree of the steam control valve 4 and smoothly converge the rotation speed of the steam turbine 2 to the target rotation speed Xt or its vicinity.

-Modification example-
Although one embodiment of the present invention has been described above, the present invention is not limited to the above-described embodiment, and the design can be appropriately changed as long as the gist of the present invention described in the claims is not deviated. ..

For example, it is not always necessary to include 0 in the choice of the manipulated variable Y for each value Xn of the rotation speed deviation X. Further, the number of options prepared as the value of the manipulated variable Y for each value Xn of the rotation speed deviation X does not have to be two, and may be three or more. By increasing the options for the operation amount Y, the speed adjustment rate of the steam control valve 4 can be adjusted more flexibly.

Further, in terms of expression, the speed adjustment rate is defined by the relationship between the rotation speed deviation X and the operation amount Y of the steam control valve 4, but the rotation speed deviation X is the target rotation speed Xt (constant) and the measured rotation speed Xm. It corresponds to the change of the measured rotation speed Xm. Therefore, the speed adjustment rate can be expressed by the relationship between the measured rotation speed Xm and the manipulated variable Y, but this is also defined by the relationship between the rotation speed deviation X and the manipulated variable Y of the steam control valve 4, although there is a difference in expression. It is synonymous with the speed adjustment rate.

Further, in the above embodiment, the limit change rate R for the manipulated variable Y of each value Xn of the rotation speed deviation X is not distinguished, but at least one of the individual rotation speed deviations Xn is different from the other rotation speed deviations. A different value of the limit change rate R may be arbitrarily set. The value of the limit change rate R of the manipulated variable Y can be arbitrarily set for each rotation speed deviation Xn, and of course, the same value can be set for the limit change rate R for all the rotation speed deviations Xn.

1 ... Boiler, 2 ... Steam turbine, 3 ... Generator, 4 ... Steam control valve, 10 ... Steam turbine control device, 11 ... Memory (storage device), 12 ... CPU (computing device), R ... Limit change rate, X ... Rotation speed deviation, X1, X2, Xa, Xn ... Individual values of rotation speed deviation, Xm ... Measured rotation speed, Xt ... Target rotation speed, Y ... Steam control valve operation amount, Yn1, Yn2 ... Operation amount options

Claims (3)

A boiler that generates steam, a steam turbine driven by the steam supplied from the boiler, a generator driven by the steam turbine, and a steam control valve that adjusts the flow rate of steam supplied from the boiler to the steam turbine. A steam turbine control equipped with a steam turbine power generation facility equipped with the above, which controls the steam control valve so that the rotation speed deviation, which is the difference between the measured rotation speed of the steam turbine and the preset target rotation speed, becomes small. In the device
It is composed of a storage device and an arithmetic unit.
In the storage device, a plurality of preset options for the target rotation speed of the steam turbine, a plurality of operating amounts of the steam control valve for each value of the rotation speed deviation, and a change in the speed adjustment rate are preset. The limit change rate is memorized,
The arithmetic unit
A speed adjustment rate function is defined by the manipulated variable selected for each value of the rotation speed deviation, and the opening degree of the steam control valve is controlled according to the rotation speed deviation under the defined speed adjustment rate function. And when the selection of the manipulated variable is changed for at least one of the individual values of the rotation speed deviation, the current speed adjustment rate function is changed to the changed speed adjustment rate function at the limit change rate. A steam turbine control device characterized by being used. The steam turbine control device according to claim 1, wherein one of a plurality of options of the manipulated variable set for each value of the rotation speed deviation is 0. A steam turbine power generation facility including the steam turbine control device according to claim 1, the boiler, the steam turbine, the generator, and the steam control valve.

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