Title of the invention: A power plant control device, a power plant, and a method for controlling the power plant.
Technical field
[0001]
This disclosure relates to a power plant control device, a power plant, and a power plant control method.
Background technology
[0002]
The power system is required to provide a stable supply of power according to the power demand. In recent years, the introduction of regenerated energy has progressed with increasing environmental awareness, but since regenerated energy is easily affected by weather conditions, conventional power generation plants (for example, thermal power generation plants and conventional power generation 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 circulating boiler system that can be used in a thermal power generation plant, a conventional power generation plant, or the like.
[0003]
In an electric power system in which the introduction of regenerative energy has progressed, the load demand on other power generation plants increases significantly under conditions such as the evening time when the output of solar power generation decreases and the electric power demand increases. Sometimes. Therefore, in other power generation 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 in response to the load increase request at the initial stage of load change until the crushed coal is put into the furnace. Will be delayed.
[0004]
On the other hand, in Patent Document 1, the generator output is relatively short-time by narrowing down the turbine bleeding valve and the deaerator water level adjusting valve of the steam generator such as a boiler to a certain opening when the load demand increases. 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.
Prior art literature
Patent documents
[0005]
Patent Document 1: Japanese Unexamined Patent Publication No. 2013-53531
Outline of the invention
Problems to be solved by the invention
[0006]
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 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 there is a risk that the generator output will be excessive with respect to fluctuations in load requirements (that is, the generator output will be temporary). There is a risk of exceeding the load command value).
[0007]
At least one aspect of the present disclosure has been made in view of the above circumstances, and can follow the output of the power plant with good responsiveness and within an appropriate range to the load command value when the load demand increases. 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.
Means to solve the problem
[0008]
The control device of the power plant according to one aspect of the present disclosure is to solve the above problem.
A steam generator configured to be able to generate steam,
A turbine configured to be driveable using the steam,
A water recovery device configured to be able to generate recovery water by condensing the steam that has finished work in the turbine,
A water recovery control valve configured to be able to adjust the supply amount of the water recovery to the steam generator,
A heater configured to heat the condensate using the bleed air from the turbine,
With 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 is increased, it is configured to perform a condensate throttle control that throttles the opening of the confluence control valve and a load increase control that increases the load of the steam generator.
The condensate throttle control is configured to control the opening of the condensing control valve and the bleeding valve at an opening change rate set based on the rate of change of the load command value.
[0009]
The power plant control method according to one aspect of the present disclosure is to solve the above problems.
A steam generator configured to be able to generate steam,
A turbine configured to be driveable using the steam,
A water recovery device configured to be able to generate recovery water by condensing the steam that has finished work in the turbine,
A water recovery control valve configured to be able to adjust the supply amount of the water recovery to the steam generator,
A heater configured to heat the condensate using the bleed air from the turbine,
With 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 is increased, the return water throttle control that narrows the opening of the return water 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 the opening degree change rate set based on the change rate of the load command value.
Effect of the invention
[0010]
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 can provide a control method for a power plant.
A brief description of the drawing
[0011]
[Fig. 1] Fig. 1 is an overall configuration diagram of a power plant according to one aspect of the present disclosure.
2 is a control flow diagram of the control device of FIG. 1. FIG.
[Fig. 3] This is an example of a characteristic function of the filtering process applied by the filter to the deviation.
[Fig. 4] Fig. 4 is a flowchart showing the mechanism of increasing generator output by condensate throttle control for each process.
[Fig. 5] Fig. 5 is a control flow diagram of a condensate discharge valve in spillover control.
[Fig. 6] Fig. 6 is a flowchart showing load response control of a power plant for each process.
[Fig. 7] Fig. 7 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 relation to each other.
Embodiment for carrying out the invention
[0012]
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 those, but are merely explanatory examples.
[0013]

FIG. 1 is an overall configuration diagram of a power plant 1 according to one aspect of the present disclosure. The power generation plant 1 includes a steam generator 2 configured to be able to generate steam. The steam generator 2 is a device capable of generating steam by applying a calorific value to 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 furnace. The boiler device may be a drum type boiler or a once-through type boiler.
[0014]
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 the 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.
[0015]
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 electric energy. The electric energy generated by the generator 5 is supplied to a power system (not shown), for example, via a predetermined path.
[0016]
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.
[0017]
A steam valve 8 (main steam valve) for adjusting the flow rate of steam supplied from the steam generator 2 to the turbine 6 is provided in the steam supply path 4 connecting the steam generator 2 and 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.
[0018]
The steam that has finished work in the turbine 6 is supplied to the water recovery device 10 located on the downstream side. The water recovery device 10 is configured to be able to generate recovery water by condensing the steam discharged from the turbine 6. Specifically, the water condensing device 10 condenses steam by exchanging heat with cooling water to generate condensate water. The condensate generated by the condensate 10 is stored in the first condensate tank 12 of the condensers 10.
[0019]
The second water recovery tank 16 is connected to the first water recovery tank 12 via the water recovery discharge line 14. The condensate generated by the condensate 10 is stored in the first condensate tank 12. An appropriate reference storage level for restoration water is set in the first restoration tank 12, and when the storage level for restoration water exceeds the reference storage level, the restoration water is stored in the first restoration tank 12. A part of the above is sent to the second condensate tank 16 via the condensate discharge line 14, so that the convalescent level of the first condensate tank 12 is properly maintained. The return water discharge line 14 is provided with a return water discharge valve 27 configured so that the flow rate of the return water flowing through the return water discharge line 14 can be adjusted.
[0020]
The condensate generated by the condensate 10 is returned to the steam generator 2 via the condensate line 22. The return water return line 22 is provided with a return water control valve 23 for adjusting the flow rate of the return water flowing through the return water line 22. Normally, the opening degree of the return water control valve 23 is controlled in order to appropriately maintain the return water level in the water return device 10 on the upstream side, but in the return water throttle control described later, the opening degree is positively adjusted. By squeezing, the flow rate of the return water flowing through the return water line 22 can be reduced.
[0021]
Further, the water recovery 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 return water 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 return water flowing through the return water 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 extracted air cooled by exchanging heat with the condensate in the plurality of heaters 24 joins the condensate line 22.
[0022]
The bleed air line 26 is provided with an bleed air valve 28 for adjusting the flow rate of the bleed air from the turbine 6. The opening degree of the bleed air 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 air valve 28 is controlled so that, for example, the bleed air corresponding to the flow rate of the condensate water of the condensate line 22 to be heat exchanged is supplied to the heater 24.
[0023]
The deaerator 25 is a device for removing dissolved oxygen, carbon dioxide, etc. contained in the condensate flowing through the condensate line 22.
[0024]
The control device 100 is a control unit of the power generation plant 1, and has a hardware configuration including, for example, an electronic arithmetic device 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 disclosure in such a hardware configuration. Possible to be configured.
[0025]
The control device 100 sends and receives control signals to and from each component of the power generation plant 1 to total the power generation plant 1.It is configured to be controllable. Such control of the power generation plant 1 is performed based on a load command value for the power generation plant 1 acquired from the outside by the control device 100. The load command value is a command value related to the load required for the power generation plant 1, and may be determined according to, for example, the supply / demand state in the power system, or may be determined manually by the operator of the power generation plant 1. good.
[0026]

Subsequently, the specific control contents by the control device 100 in the power generation 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.
[0027]
A generator output L (output of the generator 5), a load command value Ld, a steam pressure set value Ps, and a 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 generation 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 in the control device 100. The steam pressure value P can be obtained from a pressure sensor installed in the steam supply path 4.
[0028]
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.
[0029]
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 a section "0").
[0030]
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 gradient 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) having a predetermined value ΔL1 or more, the inclination is “0” and the dead band characteristic is obtained.
[0031]
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 time, so that the steam valve 8 is throttled. Is suppressed. This means that, as will be described in detail later, 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. ..
[0032]
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 deviation ΔP (= Ps−P) of the steam pressure set value Ps and 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 feed forward 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.
[0033]

Next, the condensate throttle control in the power plant 1 having the above configuration will be described. The return water throttle control is a control for increasing the output of the generator 5 by reducing the opening degree of the return water control valve 23 and the bleed air valve 28. FIG. 4 is a flowchart showing the mechanism of increasing the generator output by the condensate throttle control for each process.
[0034]
In the return water throttle control, first, the opening degree of the return water control valve 23 is operated to decrease (step S100). Such a throttle operation of the water recovery control valve 23 may be manually performed by the operator, or the water recovery control valve from the control device 100 detects a trigger signal for starting control by the control device 100. It may be automatically carried out by transmitting a control signal to 23.
[0035]
When the opening degree of the return water control valve 23 decreases, the flow rate of the return water flowing through the return water line 22 located on the downstream side of the return water control valve 23 decreases (step S101). Here, in the plurality of heaters 24 provided on the return water 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 return water flowing through the return water line 22. , The flow rate required for heat exchange with the condensate is introduced. Therefore, when the flow rate of the return water in the return water line 22 decreases as in step S101, the opening degree of the bleed air valve 28 is controlled to decrease accordingly (step S102). When the opening degree of the bleed air 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).
[0036]
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 return water throttle control is not permanent, but is temporary for a limited period after the return water throttle control is started. This is because the dewater 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.
[0037]
On the other hand, in one aspect of the present disclosure, when the load command value Ld increases, the load command value is permanently increased (for example, by manual operation by the operator of the power plant 1) in order to permanently increase the generator output L. By increasing Ld and selecting the second control route C2 when the return water throttle control is executed, the throttle of the steam valve 8 is suppressed at the time of the return water throttle control, so that the generator output by the return water throttle control is performed. It makes it easier to obtain the increase effect. In the second control route C2, the deviation ΔL is set to be larger in the negative region than 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.
[0038]

Subsequently, in order to appropriately maintain the recovery water level in the first recovery tank 12 by exchanging the recovery water generated by the water recovery device 10 between the first recovery tank 12 and the second recovery tank 16. Spillover control will be described.
[0039]
The spillover control is performed by adjusting the opening degree of the return water control valve 23 as described above in the normal time when the return water throttle control is not executed. That is, by adjusting the opening degree of the return water control valve 23 to change the amount of return water supplied to the return water line 22, the level of the return water stored in the first return water tank 12 is appropriately managed. .. On the other hand, when the return water throttle control is executed, the return water control valve 23 is throttled regardless of the return water level of the first return water tank 12 in order to increase the generator output L. Spillover control is performed by adjusting the opening degree of the return water discharge valve 27 provided between the second return water tank 16.
[0040]
FIG. 5 is a control flow diagram relating to the condensate discharge valve 27 in spillover control. In the spillover control, the recovery level F detected by the recovery level sensor (not shown) installed in the first recovery tank 12 and the appropriate recovery level target value F * corresponding to the first recovery 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 return water level becomes the return water level target value F * (that is, the deviation ΔF becomes zero).
[0041]
Here, the return water level target value F * is set by the return water 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 return water 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 return water level target value F * is F * 1 + F * 2 = F * 1 + α.
[0042]
In this way, the return water level target value F * is set larger by α when the return water throttle control is not implemented than when the return water throttle control is implemented. As a result, when the return water throttle control is not implemented, the opening degree of the return water discharge valve 27 is fixed to be small (preferably set to the fully closed state), and the return water discharge valve 27 is not involved in the spillover control. become. On the other hand, when the return water throttle control is implemented, α is not added to the return water level target value F *, so that the opening degree of the return water discharge valve 27 becomes the return water level target value F *. Feedback is controlled. As a result, even when the return water control valve 23 is in a state of being throttled by the return water throttle control, it is possible to perform spillover control by adjusting the opening degree of the return water discharge valve 27.
[0043]

Next, 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 generation 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 generation 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 the 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.
[0044]
First, the control device 100 monitors the load command value Ld input to the power generation 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 value L1 before the time t1 has reached the determination threshold. 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, the load command value Ld increases. Is determined.
[0045]
When it is determined that the load command value Ld has increased (step S201: YES), the condensate throttle control is executed (step S202). The return water throttle control is performed by reducing the opening degree of the return water control valve 23 and the bleed air valve 28 as described above. Such a throttle operation of the water recovery 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 water recovery control valve 23 and the bleeding valve 28. It may be done in a targeted manner. 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.
[0046]
Subsequently, the control device 100 controls the load increase of the steam generator 2 (step S203). As described above, the return water throttle control is limited to a temporary increase in the output of the generator 5. Therefore, by implementing the load increase control of the steam generator 2, even after the output increase effect by the return water throttle control is reduced. It is possible to follow the increase of the load command value Ld.
[0047]
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, the load increase control is less responsive than the condensate throttle control (because the initial movement at the start of the change of the load command value Ld is slow), so 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 step S203 is carried out before step S202 as shown in FIG.
[0048]
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 generation plant 1 with respect to the second steady value L2. When it has sufficiently converged (step S205: YES), it ends (END).
[0049]
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. A case where only 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 in the second comparative example, and the output of the power generation plant 1 can be temporarily increased immediately after the time t1. As mentioned above, the effect of increasing the output by controlling the water return throttle 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 furnace 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 generation plant 1 to converge to the second steady value L2 is shortened.
[0050]
Further, in the return water throttle control, the opening degree of the return water control valve 23 and the bleed air valve 28 is narrowed as described above, and the change rate of the opening degree 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 return water throttle control depends on the rate of change in the opening degree of the return water control valve 23 and the bleed air valve 28. Therefore, by controlling the opening change rate of the return water control valve 23 and the bleed air valve 28 at the time of executing the return water throttle control, the amount of change in the generator output L becomes excessive and deviates from the load command value Ld. It can be suppressed to be too much.
[0051]
In the condensate throttle control of the first comparative example of FIG. 7, since the rate of change in the opening degree of the condensate control valve 23 and the bleed air valve 28 is arbitrarily controlled in this way, the generator output L immediately after time t1. Has increased sharply, 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 condensing 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 moderately 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.
[0052]
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 method for controlling the power plant.
[0053]
In addition, it is possible to replace the constituent elements in the above-described embodiment with well-known constituent elements as appropriate without departing from the gist of the present disclosure, and the above-mentioned embodiments may be appropriately combined.
[0054]
The contents described in each of the above embodiments are grasped as follows, for example.
[0055]
(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 water recovery device (for example, the water recovery device 10 of the above embodiment) configured to be able to generate recovery water by condensing the steam that has finished work in the turbine.
A return water control valve (for example, the return water control valve 23 of the above embodiment) configured to be able to adjust the supply amount of the return water to the steam generator.
A heater configured to be able to heat the condensate using the extracted air from the turbine (for example, the heater 24 of the above embodiment) and
An bleed valve configured so that the flow rate of the bleed air can be adjusted (for example, the bleed air 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 generation plant (for example, the power generation plant 1 of the above embodiment).
When the load command value for the power plant is increased, it is configured to perform a condensate throttle control that throttles the opening of the confluence control valve and a load increase control that increases the load of the steam generator.
The condensate throttle control is configured to control the opening of the condensing control valve and the bleeding valve at an opening change rate set based on the rate of change of the load command value.
[0056]
According to the above aspect (1), when the load command value for the power plant is increased, the output of the power plant is increased by performing the water return throttle control that narrows the opening of the return water 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 implementing the condensate throttle control and the load increase control in combination in this way, it is possible to follow the output of the power generation plant with good responsiveness to the increase in the load command value.
In the return water throttle control, the opening degree of the return water control valve and the bleed air valve is controlled based on the opening change rate set based on the change rate of the load command value. As a result, the generator output by the condensate throttle control can be adjusted to correspond to the change in 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.
[0057]
(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 condensate 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).
[0058]
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.
[0059]
(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 in a region where the deviation is negative, and the opening degree of the steam valve with respect to the deviation is the non-execution of the condensing throttle during the execution of the condensing throttle control. 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).
[0060]
According to the above aspect (3), when the deviation becomes the negative side 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 at the time of performing the return water throttle control is suppressed, so that the effect of increasing the generator output by the return water throttle control can be obtained more accurately.
[0061]
(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, it is configured to be controlled to be constant (for example, in the above embodiment, the filter 108 has the characteristics shown in FIG. 3).
[0062]
According to the above aspect (4), 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.
[0063]
(5) In another aspect, in any one of the above (1) to (4),
The power plant is
A condensate discharge line configured to be able to discharge the condensate stored in the reconstitute (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.
Further prepare
During the execution of the return water throttle control, the opening degree of the return water discharge valve is adjusted to control the level of the return water in the water return device (for example, in the above embodiment, the return water throttle is controlled. The return water discharge valve 27 is controlled at the time of control to adjust the return water level).
[0064]
According to the aspect (5) above, the return water level can be appropriately managed by controlling the opening degree of the return water discharge valve while controlling the throttle of the return water control valve by the return water throttle control.
[0065]
(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.
[0066]
In the aspect of (6) above According to this, when the load command value fluctuates, the output of the power generation plant can be made to follow with good responsiveness by simultaneously performing the condensate throttle control and the load increase control.
[0067]
(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.
[0068]
According to the aspect (7) above, the output of the power generation plant can be responsively and suitably followed to a relatively large fluctuation of the load command value in which the load command value increases by 5% or more.
[0069]
(8) In another aspect, in any one of the above (1) to (7),
The load command value is input to the power generation plant from the central power supply control room according to the supply and demand state of the power system.
[0070]
According to the aspect (8) above, the output of the power generation plant can be responsively and suitably followed according to the supply and demand state of the power system.
[0071]
(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.
[0072]
According to the above aspect (9), even in a power generation 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, the output of the power generation plant can be made to follow the increase of the load command value with good responsiveness.
[0073]
(10) The power plant according to one aspect of the present disclosure is
A control device according to any one of the above (1) to (9) is provided.
[0074]
According to the above aspect (10), by performing the condensate throttle control and the load increase control in combination, the output of the power generation plant can be made to follow the increase of the load command value with good responsiveness. ..
[0075]
(11) The control method 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 water condensing device (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 return water control valve (for example, the return water control valve 23 of the above embodiment) configured to be able to adjust the supply amount of the return water to the steam generator.
A heater configured to be able to heat the condensate using the extracted air from the turbine (for example, the heater 24 of the above embodiment) and
An bleed valve configured so that the flow rate of the bleed air can be adjusted (for example, the bleed air 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 is increased, the return water throttle control that narrows the opening of the return water 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 the opening degree change rate set based on the change rate of the load command value.
[0076]
According to the above aspect (11), when the load command value for the power generation plant is increased, the output of the power generation plant is output by performing the return water throttle control that narrows the opening degree of the return water 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 implementing the condensate throttle control and the load increase control in combination in this way, it is possible to follow the output of the power generation plant with good responsiveness to the increase in the load command value.
In the return water throttle control, the opening degree of the return water control valve and the bleed air valve is controlled based on the opening change rate set based on the change rate of the load command value. As a result, the generator output by the condensate throttle control can be adjusted to correspond to the change in 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.
Description of the sign
[0077]
1 Power plant
2 Steam generator
3 Output shaft
4 Steam supply path
5 Generator
6 Turbine
8 steam valve
10 Water recovery device
12 1st water recovery tank
14 Condensation discharge line
16 Second water recovery tank
22 Water restoration line
23 Return water control valve
24 Heater
25 Deaerator
26 Lottery line
27 Return water 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 Restoration level target value setting unit
136 adder
138 switch
The scope of the claims
[Claim 1]
A steam generator configured to be able to generate steam,
A generator connected to a turbine configured to be driveable using the steam,
A water recovery device configured to be able to generate recovery water by condensing the steam that has finished work in the turbine,
A water recovery control valve configured to be able to adjust the supply amount of the water recovery to the steam generator,
A heater configured to heat the condensate using the bleed air from the turbine,
With 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 is increased, it is configured to perform a condensate throttle control that throttles the opening of the confluence control valve and a load increase control that increases the load of the steam generator.
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.
[Claim 2]
The power plant is further equipped with a steam valve for controlling the amount of steam supplied to the turbine.
The control device for a power generation 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 the execution of the condensate throttle control.
[Claim 3]
Equipped with 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.
When the load command value is increased, the steam valve control unit is in a region where the deviation is on the negative side during execution of the condensate throttle control, 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, wherein the control device is configured to be larger than the inside.
[Claim 4]
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. The control device for a power plant according to claim 3, which is configured to be controlled so as to be constant.
[Claim 5]
The power plant is
A condensate discharge line configured to be able to discharge the condensate stored in the reconstitute,
A condensate discharge valve configured to be able to adjust the flow rate of the condensate in the condensate discharge line,
Further prepare
Any of claims 1 to 4, configured to control the level of the condensate in the reconstituter by adjusting the opening degree of the condensate discharge valve during execution of the confluence throttle control. The control device for the power plant according to paragraph 1.
[Claim 6]
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.
[Claim 7]
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.
[Claim 8]
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.
[Claim 9]
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.
[Claim 10]
A power plant provided with the control device according to any one of claims 1 to 9.
[Claim 11]
A steam generator configured to be able to generate steam,
A turbine configured to be driveable using the steam,
A water recovery device configured to be able to generate recovery water by condensing the steam that has finished work in the turbine,
A water recovery control valve configured to be able to adjust the supply amount of the water recovery to the steam generator,
A heater configured to heat the condensate using the bleed air from the turbine,
With 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 is increased, the return water throttle control that narrows the opening of the return water 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 openings of the condensate control valve and the bleed air valve are controlled by the opening change rate set based on the change rate of the load command value.