WO2021020207A1

WO2021020207A1 - Power plant control device, power plant, and power plant control method

Info

Publication number: WO2021020207A1
Application number: PCT/JP2020/028090
Authority: WO
Inventors: 和宏堂本; 孝裕竹友; 道男佐々木; 尚三田
Original assignee: 三菱日立パワーシステムズ株式会社
Priority date: 2019-07-26
Filing date: 2020-07-20
Publication date: 2021-02-04
Also published as: TWI772845B; TW202126895A; JP2021021361A; JP6775070B1; KR20220019829A

Abstract

The present invention relates to a control device of a power plant which is provided with a steam generator, a turbine, a condenser, a condensate control valve, a heater and a bleed valve. When increasing the load command value to the power plant, the control device performs condensate throttle control, for throttling the opening degree of the condensate control valve, and load increase control, for increasing the load of the steam generator. In the condensate throttle control, the opening degree of the bleed air valve and the condensate control valve is controlled with an opening change rate set on the basis of the rate of change of the load command value.

Description

Power plant control device, power plant, and power plant control method

This disclosure relates to a power plant control device, a power plant, and a power plant control method.

The electric power system is required to have a stable supply of electric power according to the electric power demand. In recent years, the introduction of regenerative energy has progressed with increasing environmental awareness, but since regenerative energy is easily affected by weather conditions, conventional power plants (for example, thermal power plants and conventional power plants) Is expected to play a role in the stable supply of electric power by improving the additional adjustment power. For example, Patent Document 1 discloses a circulation type boiler system that can be used in a thermal power plant, a conventional power plant, and the like.

In an electric power system in which the introduction of regenerative energy is advanced, the load demand on other power plants increases significantly under conditions such as the evening time when the output of photovoltaic power generation decreases and the electric power demand increases. Sometimes. Therefore, in other power plants, it is required to follow the plant output in order to cope with such an increase in load demand. In a power plant, there is a considerable time lag between receiving a load command value and reflecting it in the output. For example, in a coal-fired boiler that uses coal as fuel, there is a process of crushing coal with a pulverized coal machine, so the actual output is in response to the load increase request at the initial stage of load change until the crushed coal is put into the fireplace. Will be delayed.

On the other hand, in Patent Document 1, when the load demand increases, the turbine bleeding valve and the deaerator water level adjusting valve of the steam generator such as a boiler are narrowed down to a certain opening, so that the generator output can be reduced to a relatively short time. It is disclosed that it will increase in. As a result, it is possible to improve the responsiveness without increasing the strength of the turbine as compared with the case where the increase in the load requirement is dealt with only by increasing the fuel input amount to the steam generator.

Japanese Unexamined Patent Publication No. 2013-53531

In Patent Document 1, the turbine bleeding valve of the steam generator and the water level adjusting valve of the deaerator are narrowed down to a certain opening degree to cope with an increase in load demand. However, such narrowing down of the turbine bleeding valve and the deaerator water level adjusting valve causes the generator output to increase sharply, so that the generator output may become excessive with respect to fluctuations in load requirements (that is, the generator output is temporarily increased). There is a risk that the load command value will be exceeded).

At least one aspect of the present disclosure has been made in view of the above circumstances, and when the load demand increases, the output of the power plant can be followed with good responsiveness and within an appropriate range with respect to the load command value. It is an object of the present invention to provide a control device for a power plant, a power plant, and a method for controlling the power plant.

The control device of the power plant according to one aspect of the present disclosure is used to solve the above problems.
A steam generator configured to generate steam and
A turbine configured to be driveable using the steam,
A condenser configured to generate condensate by condensing the steam that has finished its work in the turbine, and
A condensate control valve configured to be able to adjust the amount of condensate supplied to the steam generator,
A heater configured to heat the condensate using the bleed air from the turbine, and
An bleed valve configured to adjust the flow rate of the bleed air,
It is a control device of a power plant equipped with
When the load command value for the power plant increases, the condensate throttle control that narrows the opening degree of the condensate control valve and the load increase control that increases the load of the steam generator are performed.
In the condensate throttle control, the opening degrees of the condensing control valve and the bleeding valve are controlled by an opening degree change rate set based on the change rate of the load command value.

The power plant control method according to one aspect of the present disclosure is to solve the above problems.
A steam generator configured to generate steam and
A turbine configured to be driveable using the steam,
A condenser configured to generate condensate by condensing the steam that has finished its work in the turbine, and
A condensate control valve configured to be able to adjust the amount of condensate supplied to the steam generator,
A heater configured to heat the condensate using the bleed air from the turbine, and
An bleed valve configured to adjust the flow rate of the bleed air,
It is a control method of a power plant equipped with
When the load command value for the power plant increases, the condensate throttle control that narrows the opening degree of the condensate control valve and the load increase control that increases the load of the steam generator are performed.
In the condensate throttle control, the opening degrees of the condensate control valve and the bleeding valve are controlled by the opening degree change rate set based on the change rate of the load command value.

According to at least one aspect of the present disclosure, a power plant control device and a power plant capable of following the output of the power plant with good responsiveness and within an appropriate range to the load command value when a load increase request is made. , And a method of controlling a power plant can be provided.

It is an overall block diagram of the power plant which concerns on one aspect of this disclosure. It is a control flow diagram of the control device of FIG. This is an example of the characteristic function of the filtering process that the filter applies to the deviation. It is a flowchart which shows the generator output increase mechanism by a condensate throttle control for each process. It is a control flow diagram about a condensate discharge valve in spillover control. It is a flowchart which shows the load response control of a power plant for each process. This is a timing chart showing the load command value at the time of load response control and the output transition of the power plant in association with each other.

Hereinafter, some embodiments of the present invention will be described with reference to the drawings. However, the scope of the present invention is not limited to the following embodiments. The dimensions, materials, shapes, relative arrangements, and the like of the components described in the following embodiments are not intended to limit the scope of the present invention to that alone, but are merely explanatory examples.

<Structure of power plant>
FIG. 1 is an overall configuration diagram of a power plant 1 according to one aspect of the present disclosure. The power plant 1 includes a steam generator 2 configured to be capable of generating steam. The steam generator 2 is a device capable of generating steam by applying heat to the water supply. The steam generator 2 is a boiler device capable of generating steam from water supply using, for example, the amount of heat generated by burning fuel. More specifically, the boiler device is a conventional boiler capable of generating steam by crushing coal with a pulverized coal machine (not shown) and burning it in a fireplace. The boiler device may be a drum type boiler or a once-through type boiler.

The steam generated by the steam generator 2 is supplied to the turbine 6 via the steam supply path 4. The turbine 6 is rotationally driven by high-temperature and high-pressure steam generated by the steam generator 2. In FIG. 1, the turbine 6 includes a high-pressure turbine 6a arranged on the upstream side and two low-pressure turbines 6b1 and 6b2 arranged on the downstream side. The high-pressure turbine 6a and the two low-pressure turbines 6b1 and 6b2 are connected in series with each other. The two low pressure turbines 6b1 and 6b2 are connected in parallel with each other. The steam generated by the steam generator 2 first drives the high-pressure turbine 6a on the upstream side, and then drives the low-pressure turbines 6b1 and 6b2 on the downstream side.

The rotational energy of each turbine 6 driven by steam is input to the generator 5 connected to the output shaft 3 of the turbine 6. In the generator 5, the kinetic energy input from the turbine 6 is converted into electrical energy. The electric energy generated by the generator 5 is supplied to an electric power system (not shown) via a predetermined path, for example.

Although FIG. 1 illustrates a case where only the output shafts 3 of the low-pressure turbines 6b1 and 6b2 of the turbine 6 are connected to the generator 5, only the output shaft of the high-pressure turbine 6a of the turbine 6 generates power. It may be connected to the machine 5, or may be coaxially connected to the generator 5 with the output shaft of the high-pressure turbine 6a and the output shafts of the low-pressure turbines 6b1 and 6b2 as a common shaft.

The steam supply path 4 connecting the steam generator 2 and the turbine 6 is provided with a steam valve 8 (main steam valve) for adjusting the flow rate of steam supplied from the steam generator 2 to the turbine 6. The opening degree of the steam valve 8 can be controlled by a control signal from the control device 100 described later.

The steam that has finished work in the turbine 6 is supplied to the condenser 10 arranged on the downstream side. The condenser 10 is configured to be capable of generating condenser by condensing the steam discharged from the turbine 6. Specifically, the condenser 10 condenses steam by exchanging heat with the cooling water to generate condensed water. The condensate generated by the condenser 10 is stored in the first condensate tank 12 of the condenser 10.

The second condensate tank 16 is connected to the first condensate tank 12 via the condensate discharge line 14. The condensate generated by the condensate 10 is stored in the first condensate tank 12. An appropriate reference storage level for condensate is set in the first condensate tank 12, and when the condensate storage level exceeds the standard storage level, the condensate is stored in the first condensate tank 12. Is sent to the second condensate tank 16 via the condensate discharge line 14, so that the condensate level of the first condensate tank 12 is properly maintained. The condensate discharge line 14 is provided with a condensate discharge valve 27 configured so that the flow rate of the condensate flowing through the condensate discharge line 14 can be adjusted.

The condensate generated by the condenser 10 is returned to the steam generator 2 via the condensate line 22. The condensate line 22 is provided with a condensate control valve 23 for adjusting the flow rate of the condensate flowing through the condensate line 22. Normally, the opening degree of the condensate control valve 23 is controlled in order to properly maintain the condensate level in the condenser 10 on the upstream side, but in the condensate throttle control described later, the opening degree is positively adjusted. By squeezing, the flow rate of condensate flowing through the condensate line 22 can be reduced.

Further, the condensate line 22 is provided with a plurality of heaters 24 and a deaerator 25. The plurality of heaters 24 are provided in series along the condensate line 22, and are configured to be capable of raising the temperature by exchanging heat with the extracted air from the turbine 6 for the condensate flowing through the condensate line 22. The bleed air from the turbine 6 is supplied to the plurality of heaters 24 and the deaerator 25, respectively, via the bleed air line 26 extending from the turbine 6. The condensate flowing through the condensate line 22 is gradually heated by passing through the plurality of heaters 24 and then supplied to the steam generator 2. On the other hand, the bleed air cooled by exchanging heat with the condensate in the plurality of heaters 24 joins the condensate line 22.

The bleed air line 26 is provided with an bleed valve 28 for adjusting the flow rate of the bleed air from the turbine 6. The opening degree of the bleeding valve 28 is configured so that the opening degree can be adjusted based on a control signal from the control device 100 described later. The opening degree of the bleed valve 28 is controlled so that, for example, bleed air corresponding to the flow rate of the condensate of the condensate line 22, which is the heat exchange target, is supplied to the heater 24.

The deaerator 25 is a device for removing dissolved oxygen, carbon dioxide, etc. contained in the condensate flowing through the condensate line 22.

The control device 100 is a control unit of the power plant 1, and has a hardware configuration including an electronic arithmetic unit such as a computer. The control device 100 functions as a control device according to at least one aspect of the present invention by installing a program for executing the control method according to at least one aspect of the present invention in such a hardware configuration. It is configured to be possible.

The control device 100 is configured to be able to comprehensively control the power generation plant 1 by transmitting and receiving control signals to and from each component of the power generation plant 1. Such control of the power plant 1 is performed based on a load command value for the power plant 1 acquired by the control device 100 from the outside. The load command value is a command value related to the load required for the power plant 1, and may be determined according to, for example, the supply and demand state in the power system, or may be determined manually by the operator of the power plant 1. Good.

<Power plant control>
Subsequently, the specific control contents by the control device 100 in the power plant 1 having the above configuration will be described. FIG. 2 is a control flow diagram of the control device 100 of FIG. In FIG. 2, the inside of the control device 100 is shown as a functional block diagram, and the control device 100 includes a steam valve control unit 110 and a steam generator control unit 120. The steam valve control unit 110 is a functional block that outputs an opening command value of the steam valve 8 in response to an input signal, and the steam generator control unit 120 is a control parameter of the steam generator 2 in response to an input signal. It is a functional block that outputs a water supply demand signal and a fuel demand signal.

The generator output L (output of the generator 5), the load command value Ld, the steam pressure set value Ps, and the steam pressure value P are input to the control device 100, respectively. The generator output L can be acquired based on various sensors installed in the generator 5. The load command value Ld is a command value input from the outside to the power plant 1 (for example, received from the central power supply command room according to the power supply / demand state of the power system). The steam pressure set value Ps is a target value of the steam pressure generated by the steam generator 2, and is set by the control device 100. The steam pressure value P can be obtained from a pressure sensor installed in the steam supply path 4.

In the steam valve control unit 110, first, the generator output L and the load command value Ld are input to the deviation calculator 102. The deviation calculator 102 calculates and outputs the deviation ΔL (= Ld−L) of the generator output L and the load command value Ld. The deviation ΔL output from the deviation calculator 102 is input to the PI controller 106 via the switch 104. The switch 104 is a switch that can select the first control route C1 or the second control route C2 based on whether or not the condensate throttle control is executed. The first control route C1 is a control route selected at the time of normal control in which the condensate throttle control is not executed, and the deviation ΔL is directly input to the PI controller 106. On the other hand, the second control route C2 is a control route selected when the condensate throttle control is executed, and the deviation ΔL is input to the PI controller 106 via the filter 108.

The filter 108 performs a predetermined filtering process on the deviation ΔL which is an input value. Here, FIG. 3 is an example of the characteristic function f of the filtering process applied by the filter 108 to the deviation ΔL. In FIG. 3, the characteristic function f'corresponding to the case where the first control route C1 is selected is shown by a broken line for comparison (in the first control route C1, the deviation ΔL is directly input to the PI controller 106). Therefore, it is substantially equivalent to having a characteristic function f'which is a linear linear function with a slope of "1" and an intercept of "0").

The characteristic function f is set so that the output value is larger than the characteristic function f'in the negative region (that is, ΔL <0). More specifically, as shown in FIG. 3, the characteristic function f has a linear characteristic with a slope of “1” in the positive region (ΔL ≦ 0) and the subthreshold region (ΔL <ΔL1) in the negative region. In the negative region (ΔL1 ≦ ΔL <0) of the predetermined value ΔL1 or more, the slope is “0” and the dead band characteristic is obtained.

The PI controller 106 feedback-controls the opening degree of the steam valve 8 by outputting a steam valve opening command value corresponding to the deviation ΔL input to the PI controller 106. When the first control route C1 is selected by the switch 104, the PI controller 106 outputs the steam valve opening command value corresponding to the deviation ΔL calculated by the deviation calculator 102. On the other hand, when the second control route C2 is selected by the switch 104, the PI controller 106 outputs a steam valve command value corresponding to the deviation ΔL after the filtering process is performed by the filter 108. In the filter 108, as described above with reference to FIG. 3, in the negative region where the generator output L is larger than the load command value Ld, the deviation ΔL is output larger than in the normal state, so that the steam valve 8 is throttled. Is suppressed. This means that the throttle operation of the steam valve 8 is suppressed when the deviation ΔL becomes the negative side region by executing the condensate throttle control when the load command value increases, as will be described in detail later. ..

On the other hand, in the steam generator control unit 120, the steam pressure set value Ps and the steam pressure value P are input to the deviation calculator 122. The deviation calculator 122 outputs the steam pressure set value Ps and the deviation ΔP (= Ps−P) of the steam pressure value P. The deviation ΔP output from the deviation calculator 122 is input to the PI controller 124. The PI controller 124 outputs an output signal corresponding to the deviation ΔP. The load command value Ld is added as a feedforward component by the adder 126 to the output signal output from the PI controller 124, so that the load followability of the steam generator 2 is improved. Such a control signal of the steam generator 2 is output to the steam generator 2 to be controlled as a water supply demand signal Sw and a fuel demand signal Sf, which are control parameters of the steam generator 2.

<Condenser throttle control>
Subsequently, the condensate throttle control in the power plant 1 having the above configuration will be described. The condensate throttle control is a control for increasing the output of the generator 5 by reducing the opening degree of the condensate control valve 23 and the bleed air valve 28. FIG. 4 is a flowchart showing the generator output increase mechanism by the condensate throttle control for each process.

In the condensate throttle control, first, the opening of the condensate control valve 23 is reduced (step S100). Such a throttle operation of the condensate control valve 23 may be manually performed by the operator, or the condensate control valve from the control device 100 detects a trigger signal for starting control by the control device 100. It may be carried out automatically by transmitting a control signal to 23.

When the opening degree of the condensate control valve 23 decreases, the flow rate of condensate flowing through the condensate line 22 located on the downstream side of the condensate control valve 23 decreases (step S101). Here, in the plurality of heaters 24 provided on the condensate line 22, as described above, the opening degree of the bleeding valve 28 is controlled so as to correspond to the flow rate of the condensate flowing through the condensate line 22. , The flow rate required for heat exchange with condensate is introduced. Therefore, when the flow rate of the condensate in the condensate line 22 decreases as in step S101, the opening degree of the bleeding valve 28 is controlled to decrease accordingly (step S102). When the opening degree of the bleed valve 28 decreases, the bleed air supplied to the heater 24 decreases, so that the amount of steam flowing through the turbine 6 increases (step S103) and the generator output L increases (step S104).

By executing the condensate throttle control in this way, the output of the generator 5 can be increased. However, the effect of increasing the generator output by the condensate throttle control is not permanent, but is temporary for a limited period after the condensate throttle control is started. This is because the condensate flow rate is reduced by the condensate throttle control, so that the deaerator level in the deaerator 25 is lowered and the water supply to the steam generator 2 cannot be continued. As a result, the effect of increasing the generator output by the condensate throttle control decreases after a temporary period.

On the other hand, in one aspect of the present disclosure, when the load command value Ld increases, the load command value (for example, by manual operation by the operator of the power plant 1) is used to permanently increase the generator output L. By increasing Ld and selecting the second control route C2 when the condensate throttle control is executed, the throttle of the steam valve 8 is suppressed during the condensate throttle control, so that the generator output by the condenser throttle control It makes it easier to obtain an increase effect. In the second control route C2, the deviation ΔL is set to be larger in the negative side region than in the first control route C1 by performing the filtering process by the filter 108. As a result, the steam valve 8 is less likely to be throttled when the condensate throttle control is executed, so that the effect of increasing the generator output can be easily obtained.

<Spillover control>
Subsequently, the condensate generated by the condenser 10 is exchanged between the first condensate tank 12 and the second condensate tank 16 in order to appropriately maintain the condensate level in the first condensate tank 12. The spillover control of is described.

The spillover control is performed by adjusting the opening degree of the condensate control valve 23 as described above in the normal time when the condensate throttle control is not executed. That is, by adjusting the opening degree of the condensate control valve 23 to change the amount of condensate supplied to the condensate line 22, the level of condensate stored in the first condensate tank 12 is appropriately managed. .. On the other hand, when the condensate throttle control is executed, the condensate control valve 23 is throttled regardless of the condensate level of the first condensate tank 12 in order to increase the generator output L, so that the first condensate tank 12 and Spillover control is performed by adjusting the opening degree of the condensate discharge valve 27 provided between the second condensate tanks 16.

FIG. 5 is a control flow diagram relating to the condensate discharge valve 27 in the spillover control. In the spillover control, the condensate level F detected by the condensate level sensor (not shown) installed in the first condensate tank 12 and the appropriate condensate level target value F * corresponding to the first condensate tank 12. Is input to the deviation calculation unit 130 to calculate the deviation ΔF. When the deviation ΔF is input to the PI controller 132, the condensate discharge valve opening command value corresponding to the deviation ΔF is output. As a result, feedback control is performed so that the condensate level becomes the condensate level target value F * (that is, the deviation ΔF becomes zero).

Here, the condensate level target value F * is set by the condensate level target value setting unit 134. In the return water level target value setting unit 134, the return water level target value F * is set by adding the addition target value F * 2 to the normal target value F * 1 in the adder 136. As the addition target value F * 2, either "0" or "α (a number larger than zero)" is selected based on whether or not the condensate throttle control is being executed. Specifically, when the condensate throttle control is being executed, the switch 138 selects "0" as the addition target value F * 2. In this case, the condensate level target value F * is F * 1 + F * 2 (= 0) = F * 1. On the other hand, in the normal time when the condensate throttle control is not executed, the switch 138 selects "α" as the addition target value F * 2. In this case, the condensate level target value F * is F * 1 + F * 2 = F * 1 + α.

In this way, the condensate level target value F * is set larger by α when the condensate throttle control is not implemented than when the condensate throttle control is implemented. As a result, when the condensate throttle control is not implemented, the opening degree of the condensate discharge valve 27 is fixed to be small (preferably set to the fully closed state), and the condensate discharge valve 27 is not involved in the spillover control. become. On the other hand, when the condensate throttle control is implemented, α is not added to the condensate level target value F *, so that the opening degree of the condensate discharge valve 27 becomes the condensate level target value F *. Feedback is controlled. As a result, even when the condensate control valve 23 is in a state of being throttled by the condensate throttle control, it is possible to perform spillover control by adjusting the opening degree of the condensate discharge valve 27.

<Load response control>
Subsequently, the load response control of the power plant 1 when the load command value Ld for the power plant 1 increases and fluctuates will be specifically described. FIG. 6 is a flowchart showing the load response control of the power plant 1 for each process, and FIG. 7 is a timing chart showing the load command value Ld at the time of load response control and the output transition of the power plant 1 in association with each other. Here, as shown in FIG. 7, a case where the load command value Ld, which was in the first steady value L1 as an initial state, monotonically increases from time t1 to time t2 and fluctuates so as to increase to the second steady value L2. Let's take an example.

First, the control device 100 monitors the load command value Ld input to the power plant (step S200), and determines whether or not the load command value Ld has increased (step S201). The determination in step S201 is performed based on, for example, whether or not the amount of change in the load command value Ld with respect to the first steady-state value L1 before the time t1 has reached the determination threshold value. In one aspect of the present disclosure, for example, in the control device 100, when the rate of change of the load command value Ld (the amount of change of the load command value Ld in a predetermined period) exceeds the determination threshold value, the load command value Ld increases. Is determined.

When it is determined that the load command value Ld has increased (step S201: YES), the condensate throttle control is executed (step S202). The condensate throttle control is performed by reducing the opening degree of the condensate control valve 23 and the bleed air valve 28 as described above. Such a throttle operation of the condensate control valve 23 may be manually performed by, for example, an operator, or is automatically performed by transmitting a control signal from the control device 100 to the condensate control valve 23 and the bleeding valve 28. It may be done as a target. When the condensate throttle control is performed in step S202, the output of the generator 5 temporarily increases as described above with reference to FIG.

Subsequently, the control device 100 performs load increase control of the steam generator 2 (step S203). Since the condensate throttle control is limited to a temporary increase in the output of the generator 5 as described above, the output increase effect of the condensate throttle control is reduced by performing the load increase control of the steam generator 2. It is possible to follow the increase of the load command value Ld.

Although it is described in FIG. 6 that step S203 is performed after step S202 is performed for the sake of formality, steps S202 and S203 may be performed at the same time. That is, the condensate throttle control and the load increase control may be performed at the same time. As described above, since the load increase control is less responsive than the condensate throttle control (because the initial action at the start of the change of the load command value Ld is slow), it is preferable to carry out these at the same time. Further, within the scope of the idea, it is undeniable that step S203 is carried out after step S202 and that step S203 is carried out before step S202 as shown in FIG.

Such condensate throttle control and load increase control are continued until the load command value Ld reaches the second steady value L2 (step S204: YES), and the output of the power plant 1 with respect to the second steady value L2. When the convergence is sufficient (step S205: YES), the process ends (END).

Here, in FIG. 7, as a comparative example, when only the condensate throttle control is performed from time t1 (first comparative example), and the load increase of the steam generator 2 is performed from time t1 without performing the condensate throttle control. The case where only the control is performed (second comparative example) is shown. In the first comparative example, since only the condensate throttle control is performed, the response is better than that in the second comparative example, and the output of the power plant 1 can be temporarily increased immediately after the time t1. As mentioned above, the effect of increasing the output by the condensate throttle control does not last forever. In the second comparative example, only the load increase control is performed, and the responsiveness is low. In particular, when the steam generator 2 is a device such as a coal-fired boiler, there is a process of crushing coal with a pulverized coal machine, so there is a time lag until the crushed coal is input to the fireplace and reflected in the output. Is large and the responsiveness is poor. In contrast to these comparative examples, in this embodiment, by combining the condensate throttle control and the load increase control when the load command value Ld increases, good responsiveness to a change in the load command value Ld can be obtained, and at the same time, good responsiveness can be obtained. It has been shown that the time required for the output of the power plant 1 to converge to the second steady-state value L2 is shortened.

Further, in the condensate throttle control, the opening degrees of the condensate control valve 23 and the bleeding valve 28 are narrowed as described above, and the opening change rate at that time is the change rate of the load command value Ld acquired in step S200. Set based on. The amount of change in the generator output L due to the condensate throttle control depends on the rate of change in the opening degree of the condensate control valve 23 and the bleed air valve 28. Therefore, by controlling the rate of change in the opening degree of the condensate control valve 23 and the bleeding valve 28 when the condensate throttle control is executed, the amount of change in the generator output L becomes excessive, which deviates from the load command value Ld. It can be suppressed to be too much.

In the condensate throttle control of the first comparative example of FIG. 7, since the rate of change of the opening degree of the condensate control valve 23 and the bleeding valve 28 is arbitrarily controlled in this way, the generator output L is immediately after time t1. Has increased rapidly, and the amount of deviation from the load command value Ld has increased. On the other hand, in this embodiment, by setting the rate of change of the opening degree of the condensate control valve 23 and the bleeding valve 28 based on the rate of change of the load command value Ld, immediately after the time t1 as compared with the first comparative example. The increase in the generator output L in the above is appropriately suppressed, and the amount of deviation from the load command value Ld is small. This indicates that the generator output L by the condensate throttle control can be adjusted so as to correspond to the change of the load command value Ld, and good followability is obtained.

As described above, according to at least one aspect of the present disclosure, a power plant capable of following the output of the power plant with good responsiveness and within an appropriate range to the load command value when a load increase request is made. It is possible to provide a control device, a power plant, and a control method for the power plant.

In addition, it is possible to replace the components in the above-described embodiment with well-known components as appropriate without departing from the spirit of the present disclosure, and the above-described embodiments may be combined as appropriate.

The contents described in each of the above embodiments are grasped as follows, for example.

(1) The control device of the power plant according to one aspect of the present disclosure is
A steam generator configured to be able to generate steam (for example, the steam generator 2 of the above embodiment) and
A turbine configured to be driveable using the steam (for example, the turbine 6 of the above embodiment) and
A condenser (for example, the condenser 10 of the above embodiment) configured to be able to generate condensate by condensing the steam that has finished its work in the turbine.
A condensate control valve (for example, the condensate control valve 23 of the above embodiment) configured to be able to adjust the supply amount of the condensate to the steam generator.
A heater configured to heat the condensate using the bleed air from the turbine (for example, the heater 24 of the above embodiment) and
An bleeding valve configured so that the flow rate of the bleeding air can be adjusted (for example, the bleeding valve 28 of the above embodiment) and
(For example, the control device (for example, the control device 100 of the above embodiment) of the power plant (for example, the power plant 1 of the above embodiment).
When the load command value for the power plant increases, the condensate throttle control that narrows the opening degree of the condensate control valve and the load increase control that increases the load of the steam generator are performed.
In the condensate throttle control, the opening degrees of the condensing control valve and the bleeding valve are controlled by an opening degree change rate set based on the change rate of the load command value.

According to the aspect (1) above, when the load command value for the power plant is increased, the output of the power plant is increased by performing the condensate throttle control that narrows the opening of the condensate control valve in addition to the load increase control. It can be increased responsively. As a result, better responsiveness can be obtained as compared with the case where only the load increase control, which takes a relatively long time to respond, is performed. Further, by implementing the condensate throttle control and the load increase control, the output of the power plant can be increased until the target load is reached even when the change in the load command value is large. By performing the condensate throttle control and the load increase control in combination in this way, it is possible to follow the output of the power plant with good responsiveness to an increase in the load command value.
Further, in the condensate throttle control, the opening degree of the condensate control valve and the bleeding valve is controlled based on the opening degree change rate set based on the change rate of the load command value. Thereby, the generator output by the condensate throttle control can be adjusted so as to correspond to the change of the load command value. As a result, when the condensate throttle control is performed, it is suppressed that the generator output greatly exceeds the load command value and deviates, and good followability to the load command value can be obtained.

(2) In another aspect, in the above aspect (1),
The power plant further includes a steam valve (for example, the steam valve 8 of the above embodiment) for controlling the amount of steam supplied to the turbine.
During the execution of the condensate throttle control, it is configured to suppress a decrease in the opening command value for the steam valve due to the execution of the condensing throttle control (for example, in the above embodiment, the steam valve opening command value is set. The deviation ΔL input to the output PI controller 106 is corrected by the filter 108).

According to the aspect (2) above, when the condensate throttle control is performed, the decrease in the opening degree of the steam valve is suppressed. As a result, when the generator output is temporarily increased by the condensate throttle control, the opening of the steam valve is reduced so as to reduce the generator output exceeding the target output, so that the generator output is reduced. Can be suppressed. As a result, the effect of increasing the generator output by the condensate throttle control can be obtained more accurately.

(3) In another aspect, in the above aspect (1),
A steam valve control unit (for example, the steam valve control unit 110 of the above embodiment) configured to be able to control the opening degree of the steam valve based on the deviation between the output of the generator and the load command value is provided.
When the load command value is increased, the steam valve control unit is performing the condensate throttle control, the deviation is in the negative side region, and the opening degree of the steam valve with respect to the deviation is the non-execution of the condensate throttle. It is configured to be controlled to be larger than the inside (for example, in the above embodiment, the filter 108 has the characteristics shown in FIG. 3).

According to the aspect (3) above, when the deviation becomes a negative region due to the condensate throttle control being performed, the opening degree of the steam valve is larger than that when the condensate throttle control is not carried out. It is controlled to be large. As a result, the decrease in the opening degree of the steam valve when the condensate throttle control is performed is suppressed, so that the effect of increasing the generator output by the condensate throttle control can be obtained more accurately.

(4) In another aspect, in the above aspect (3),
When the load command value is increased, the steam valve control unit sets the opening degree of the steam valve with respect to the deviation to the deviation in the negative region where the deviation is equal to or more than a predetermined value during the execution of the condensate throttle control. On the other hand, the filter 108 is configured to be controlled so as to be constant (for example, in the above embodiment, the filter 108 has the characteristics shown in FIG. 3).

According to the aspect (4) above, when the deviation is in the negative region of a predetermined value or more, the opening degree of the steam valve is suppressed to be constant, so that the effect of increasing the generator output by the condensate throttle control can be obtained. It can be obtained more accurately.

(5) In another aspect, in any one of the above (1) to (4),
The power plant
A condensate discharge line configured to be able to discharge the condensate stored in the condensate (for example, the condensate discharge line 14 of the above embodiment) and
A condensate discharge valve (for example, the condensate discharge valve 27 of the above embodiment) configured to be able to adjust the flow rate of the condensate in the condensate discharge line.
With more
During the execution of the condensate throttle control, the opening degree of the condensate discharge valve is adjusted to control the level of the condensate in the condenser (for example, the condensate throttle in the above embodiment). The condensate discharge valve 27 is controlled at the time of control to adjust the condensate level).

According to the aspect (5) above, the condensate level can be appropriately managed by controlling the opening degree of the condensate discharge valve while controlling the condensate control valve by the condensate throttle control.

(6) In another aspect, in any one of the above (1) to (5),
The condensate throttle control and the load increase control are performed at the same time.

According to the aspect (6) above, the output of the power plant can be followed with good responsiveness by simultaneously performing the condensate throttle control and the load increase control when the load command value fluctuates.

(7) In another aspect, in any one of the above (1) to (6),
It is configured to execute the condensate throttle control when the load command value increases by 5% or more.

According to the aspect (7) above, the output of the power plant can be responsively and suitably followed with respect to a relatively large fluctuation of the load command value in which the load command value increases by 5% or more.

(8) In another aspect, in any one of the above (1) to (7),
The load command value is input to the power plant from the central power supply control room according to the supply and demand state of the power system.

According to the aspect (8) above, the output of the power plant can be responsively and suitably followed according to the supply and demand state of the electric power system.

(9) In another aspect, in any one of the above (1) to (8),
The steam generator is a coal-fired boiler that uses coal as fuel.

According to the above aspect (9), even in a power plant using a coal-fired boiler as a steam generator, which has a low response to a load command value by operation control due to a process of crushing coal with a pulverized coal machine. By implementing the condensate throttle control and the load increase control in combination, it is possible to follow the output of the power plant with good responsiveness to the increase in the load command value.

(10) The power plant according to one aspect of the present disclosure is
The control device according to any one of (1) to (9) above is provided.

According to the aspect (10) above, by performing the condensate throttle control and the load increase control in combination, the output of the power plant can be made to follow the increase of the load command value with good responsiveness. ..

(11) The power plant control method according to one aspect of the present disclosure is
A steam generator configured to be able to generate steam (for example, the steam generator 2 of the above embodiment) and
A turbine configured to be driveable using the steam (for example, the turbine 6 of the above embodiment) and
A condenser (for example, the condensate control valve 23 of the above embodiment) configured to be able to generate condensate by condensing the steam that has finished work in the turbine.
A condensate control valve (for example, the condensate control valve 23 of the above embodiment) configured to be able to adjust the supply amount of the condensate to the steam generator.
A heater configured to heat the condensate using the bleed air from the turbine (for example, the heater 24 of the above embodiment) and
An bleeding valve configured so that the flow rate of the bleeding air can be adjusted (for example, the bleeding valve 28 of the above embodiment) and
A control method for a power plant (for example, the power plant 1 of the above embodiment).
When the load command value for the power plant increases, the condensate throttle control that narrows the opening degree of the condensate control valve and the load increase control that increases the load of the steam generator are performed.
In the condensate throttle control, the opening degrees of the condensate control valve and the bleeding valve are controlled by the opening degree change rate set based on the change rate of the load command value.

According to the aspect (11) above, when the load command value for the power plant is increased, the output of the power plant is increased by performing the condensate throttle control that narrows the opening degree of the condensate control valve in addition to the load increase control. It can be increased responsively. As a result, better responsiveness can be obtained as compared with the case where only the load increase control, which takes a relatively long time to respond, is performed. Further, by implementing the condensate throttle control and the load increase control, the output of the power plant can be increased until the target load is reached even when the change in the load command value is large. By performing the condensate throttle control and the load increase control in combination in this way, it is possible to follow the output of the power plant with good responsiveness to an increase in the load command value.
Further, in the condensate throttle control, the opening degree of the condensate control valve and the bleeding valve is controlled based on the opening degree change rate set based on the change rate of the load command value. Thereby, the generator output by the condensate throttle control can be adjusted so as to correspond to the change of the load command value. As a result, when the condensate throttle control is performed, it is suppressed that the generator output greatly exceeds the load command value and deviates, and good followability to the load command value can be obtained.

1 Power plant 2 Steam generator 3 Output shaft 4 Steam supply path 5 Generator 6 Turbine 8 Condenser 10 Condenser 12 1st condensate tank 14 Condensation discharge line 16 2nd condensate tank 22 Condensation line 23 Condensation Control valve 24 Heater 25 Deaerator 26 Condenser line 27 Condenser discharge valve 28 Extraction valve 100 Control device 102 Deviation calculator 104 Switch 106 PI controller 108 Filter 110 Steam valve control unit 120 Steam generator control unit 122 Deviation calculator 124 PI controller 126 adder 130 deviation calculation unit 132 PI controller 134 condensate level target value setting unit 136 adder 138 switch

Claims

A steam generator configured to generate steam and
A generator connected to a turbine configured to be driveable using the steam,
A condenser configured to generate condensate by condensing the steam that has finished its work in the turbine, and
A condensate control valve configured to be able to adjust the amount of condensate supplied to the steam generator,
A heater configured to heat the condensate using the bleed air from the turbine, and
An bleed valve configured to adjust the flow rate of the bleed air,
It is a control device of a power plant equipped with
When the load command value for the power plant increases, the condensate throttle control that narrows the opening degree of the condensate control valve and the load increase control that increases the load of the steam generator are performed.
In the condensate throttle control, the opening degree of the condensate control valve and the bleeding valve is controlled by the opening degree change rate set based on the change rate of the load command value. Control device.
The power plant further comprises a steam valve for controlling the amount of steam supplied to the turbine.
The control device for a power plant according to claim 1, which is configured to suppress a decrease in an opening command value for the steam valve due to the execution of the condensate throttle control during execution of the condensate throttle control.
A steam valve control unit configured to be able to control the opening degree of the steam valve based on the deviation between the output of the generator and the load command value is provided.
When the load command value is increased, the steam valve control unit is performing the condensate throttle control, the deviation is in the negative side region, and the opening degree of the steam valve with respect to the deviation is the non-execution of the condensate throttle. The control device for a power plant according to claim 1, which is configured to be controlled so as to be larger than the inside.
When the load command value is increased, the steam valve control unit sets the opening degree of the steam valve with respect to the deviation to the deviation in the negative region where the deviation is equal to or more than a predetermined value during execution of the condensate throttle control. The control device for a power plant according to claim 3, which is configured to be controlled so as to be constant.
The power plant
A condensate discharge line configured to discharge the condensate stored in the condensate,
A condensate discharge valve configured to be able to adjust the flow rate of the condensate in the condensate discharge line,
With more
Any of claims 1 to 4, which is configured to control the level of the condenser in the condenser by adjusting the opening degree of the condenser discharge valve during the execution of the condenser control. The control device for the power plant according to paragraph 1.
The control device for a power plant according to any one of claims 1 to 5, wherein the condensate throttle control and the load increase control are performed at the same time.
The control device for a power plant according to any one of claims 1 to 6, which is configured to execute the condensate throttle control when the load command value increases by 5% or more.
The control device for a power plant according to any one of claims 1 to 7, wherein the load command value is input to the power plant from the central power supply control room according to the supply and demand state of the power system.
The control device for a power plant according to any one of claims 1 to 8, wherein the steam generator is a coal-fired boiler that uses coal as fuel.
A power plant provided with the control device according to any one of claims 1 to 9.
A steam generator configured to generate steam and
A turbine configured to be driveable using the steam,
A condenser configured to generate condensate by condensing the steam that has finished its work in the turbine, and
A condensate control valve configured to be able to adjust the amount of condensate supplied to the steam generator,
A heater configured to heat the condensate using the bleed air from the turbine, and
An bleed valve configured to adjust the flow rate of the bleed air,
It is a control method of a power plant equipped with
When the load command value for the power plant increases, the condensate throttle control that narrows the opening degree of the condensate control valve and the load increase control that increases the load of the steam generator are performed.
In the condensate throttle control, a power plant control method in which the opening degrees of the condensate control valve and the bleeding valve are controlled by an opening degree change rate set based on the change rate of the load command value.