KR102704840B1 - Control device of power plant, power plant and control method of power plant - Google Patents

Abstract

The present invention relates to a control device for a power plant having a steam generator, a turbine, a condenser, a condenser control valve, a heater, and a steam extraction valve. The control device performs a steam throttling control for narrowing the opening of the condenser control valve when a load command value for the power plant increases, and a load increase control for increasing the load of the steam generator. In the steam throttling control, the openings of the condenser control valve and the steam extraction valve are controlled at an opening change rate that is set based on a change rate of the load command value.

Description

Control device of power plant, power plant and control method of power plant

The present disclosure relates to a control device for a power plant, a power plant, and a control method for a power plant.

In the power system, a stable supply of electricity according to the demand for electricity is required. In recent years, with the increase in environmental awareness, the introduction of renewable energy has been progressing, but since renewable energy is easily affected by weather conditions and fluctuates, it is expected that conventional power generation plants (e.g., thermal power generation plants, conventional power generation plants, etc.) will play a role in the stable supply of electricity by improving the additional adjustment ability. For example, Patent Document 1 discloses a circulation boiler system that can be used in thermal power generation plants, conventional power generation plants, etc.

In power systems where renewable energy is being introduced, there are cases where load demands on other power plants increase significantly, for example, when the output of solar power generation decreases and also in the evening when power demand increases. Therefore, other power plants are required to follow the plant output in order to respond to such increases in load demands. In power plants, a considerable amount of time lag occurs between when the load command value is received and when it is reflected in the output. For example, in a coal-fired boiler that uses coal as fuel, since there is a process of crushing coal in a coal pulverizer, the actual output is delayed in response to the load increase demand during the initial stage of the load change until the crushed coal is fed into the furnace.

In contrast, Patent Document 1 discloses that when the load demand increases, the turbine extraction valve and the deaerator water level adjustment valve of a steam generator such as a boiler are narrowed to a certain degree of opening, thereby increasing the generator output in a relatively short period of time. As a result, compared to a case where the load demand increase is responded to by simply increasing the amount of fuel input to the steam generator, the responsiveness can be improved without increasing the strength of the turbine.

Japanese Patent Publication No. 2013-53531

In the above patent document 1, the turbine bleed valve and the deaerator water level adjustment valve of the steam generator are narrowed to a certain degree of opening in order to respond to an increase in load demand. However, since such throttling of the turbine bleed valve and the deaerator water level adjustment valve rapidly increases the generator output, there is a concern that it may become excessive in response to fluctuations in the load demand (i.e., there is a concern that the generator output may temporarily exceed the load command value).

At least one aspect of the present disclosure has been made in consideration of the above-described circumstances, and it is an object of the present disclosure to provide a control device for a power generation plant, a power generation plant, and a control method for the power generation plant capable of following the output of the power generation plant with good responsiveness and within an appropriate range with respect to a load command value when a load demand increases.

In order to solve the above problem, the control device of the power plant according to one aspect of the present disclosure,

A steam generator configured to generate steam,

A turbine configured to be driven using the above steam,

A condenser configured to generate condensate by condensing the steam that has completed work in the turbine;

A plurality of regulating valves configured to be capable of adjusting the supply amount to the plurality of steam generators,

A heater configured to heat the plural by using the exhaust from the turbine;

A bleed valve configured to be able to adjust the flow rate of the above bleeder

It is a control device for a power plant equipped with

When the load command value for the above power generation plant increases, it is configured to perform multiple throttling control to narrow the opening degree of the above multiple control valves and load increase control to increase the load of the above steam generator.

In the above multiple throttling control, the openings of the multiple regulating valves and the bleed valve are configured to be controlled at an opening change rate set based on a change rate of the load command value.

In order to solve the above problem, a control method of a power plant according to one aspect of the present disclosure is provided.

A steam generator configured to generate steam,

A turbine configured to be driven using the above steam,

A condenser configured to generate condensate by condensing the steam that has completed work in the turbine;

A plurality of regulating valves configured to be capable of adjusting the supply amount to the plurality of steam generators,

A heater configured to heat the plural by using the exhaust from the turbine;

A bleed valve configured to be capable of adjusting the flow rate of the above bleed

A control method for a power plant equipped with a

When the load command value for the above power generation plant increases, a multiple throttling control is performed to narrow the opening of the multiple control valves, and a load increase control is performed to increase the load of the steam generator.

In the above multiple throttling control, the openings of the multiple regulating valves and the bleed valve are controlled based on the opening change rate set based on the change rate of the load command value.

According to at least one aspect of the present disclosure, a control device for a power generation plant, a power generation plant and a control method for a power generation plant can be provided, which can follow the output of the power generation plant with good responsiveness and within an appropriate range with respect to a load command value when a load increase is requested.

Figure 1 is a general configuration diagram of a power generation plant according to one embodiment of the present disclosure.
Figure 2 is a control flow diagram of the control device of Figure 1.
Figure 3 is an example of a characteristic function of the filtering process applied to the deviation.
Figure 4 is a flow chart showing the mechanism for increasing generator output by multiple throttling control for each process.
Figure 5 is a control flow diagram regarding multiple discharge valves in spillover control.
Figure 6 is a flow chart showing the load response control of a power plant for each process.
Figure 7 is a timing chart showing the relationship between the load command value and the output trend of the power plant during load response control.

Hereinafter, several 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 embodiments below. The dimensions, materials, shapes, relative arrangements, etc. of the component parts described in the embodiments below are not intended to limit the scope of the present invention to these, but are merely illustrative examples.

<Composition of power plant>

FIG. 1 is a diagram showing the overall configuration of a power plant (1) according to one embodiment of the present disclosure. The power plant (1) has a steam generator (2) configured to be capable of generating steam. The steam generator (2) is a device capable of generating steam by providing heat to feedwater. The steam generator (2) is a boiler device capable of generating steam from feedwater using heat generated by, for example, burning fuel. More specifically, the boiler device is a conventional boiler capable of generating steam by pulverizing coal in a coal pulverizer (not shown) and burning it in a furnace. The boiler device may be a drum-type boiler or a once-through boiler.

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

The rotational energy of each turbine (6) driven by steam is input to a 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 electrical energy generated in the generator (5) is supplied to a power system (not shown) through a predetermined path, for example.

In addition, although FIG. 1 exemplifies a case where only the output shaft (3) of the low-pressure turbine (6b1, 6b2) among the turbines (6) is connected to the generator (5), only the output shaft of the high-pressure turbine (6a) among the turbines (6) may be connected to the generator (5), or the output shaft of the high-pressure turbine (6a) and the output shaft of the low-pressure turbine (6b1, 6b2) may be coaxially connected to the generator (5) as a common shaft.

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 line (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 a control device (100) described later.

The steam that has finished its work in the turbine (6) is supplied to the condenser (10) located on the downstream side. The condenser (10) is configured to be able to generate condensate by condensing the steam discharged from the turbine (6). Specifically, the condenser (10) condenses the steam and generates condensate by exchanging heat with cooling water. The condensate generated in the condenser (10) is stored in the first condensate tank (12) that the condenser (10) has.

A second plurality tank (16) is connected to the first plurality tank (12) via a plurality discharge line (14). The plurality generated in the condenser (10) is stored in the first plurality tank (12). An appropriate plurality reference storage level is set in the first plurality tank (12), and when the plurality storage level exceeds the standard storage level, a portion of the plurality stored in the first plurality tank (12) is sent to the second plurality tank (16) via the plurality discharge line (14), thereby maintaining the plurality level in the first plurality tank (12) appropriately. A plurality discharge valve (27) configured to be able to adjust the flow rate of the plurality flowing in the plurality discharge line (14) is provided in the plurality discharge line (14).

The plural generated in the pluralizer (10) is returned to the steam generator (2) through the plural line (22). The plural line (22) is provided with a plural control valve (23) for adjusting the plural flow rate flowing through the plural line (22). The plural control valve (23) is normally controlled to have an opening degree in order to appropriately maintain the plural level in the pluralizer (10) located on the upstream side, but in the plural throttling control described later, the plural flow rate flowing through the plural line (22) is configured to be reduced by actively narrowing the opening degree.

In addition, a plurality of heaters (24) and a deaerator (25) are provided in the plurality of lines (22). The plurality of heaters (24) are provided in series along the plurality of lines (22) and are configured to be able to increase the temperature of the condensate flowing through the plurality of lines (22) by heat-exchanging with the exhaust air from the turbine (6). The exhaust air from the turbine (6) is supplied to the plurality of heaters (24) and the deaerator (25) through the exhaust line (26) extending from the turbine (6). The condensate flowing through the plurality of lines (22) is gradually heated by passing through the plurality of heaters (24) and then supplied to the steam generator (2). Meanwhile, the exhaust air cooled by heat-exchanging with the condensate through the plurality of heaters (24) joins the plurality of lines (22).

In the bleed line (26), a bleed valve (28) is provided to adjust the flow rate of bleed from the turbine (6). The opening degree of the bleed valve (28) is configured to be adjustable based on a control signal from a control device (100) described later. The opening degree of the bleed valve (28) is controlled so that, for example, bleed corresponding to the flow rate of the plurality of lines (22) that are the heat exchange target is supplied to the heater (24).

The degassing device (25) is a device for removing dissolved oxygen or carbon dioxide 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 consisting of an electronic computing device such as a computer, for example. The control device (100) is configured to function as a control device according to at least one aspect of the present invention by installing a program for executing a control method according to at least one aspect of the present disclosure on such a hardware configuration.

The control device (100) is configured to comprehensively control the power generation plant (1) by transmitting and receiving control signals between each component of the power generation plant (1). Such control of the power generation plant (1) is performed based on a load command value for the power generation plant (1) that the control device (100) acquires from the outside. The load command value is a command value regarding the load required for the power generation plant (1), and may be determined according to, for example, the supply and demand status in the power system, or may be determined by an operator of the power generation plant (1) manually setting it.

<Control of power plant>

Continuing, 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. 1. In FIG. 2, the interior of the control device (100) is shown as a functional block diagram, and the control device (100) is provided with 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 functional block that outputs a feedwater demand signal and a fuel demand signal, which are control parameters of the steam generator (2), in response to an input signal.

In the control device (100), 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 each input. 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 and demand status of the power system). The steam pressure set value Ps is a target value of the steam pressure generated in the steam generator (2) and is set in the control device (100). The steam pressure value P can be acquired from a pressure sensor installed in the steam supply line (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 multiple throttling control is being executed. The first control route C1 is a control route that is selected during normal control when multiple throttling control is not being executed, and the deviation ΔL is input as is to the PI controller (106). The second control route C2 on one side is a control route selected when executing multiple throttling control, and the deviation ΔL is input to the PI controller (106) through the filter (108).

The filter (108) performs a predetermined filtering process on the input value, the deviation ΔL. Here, FIG. 3 is an example of a characteristic function f of the filtering process that the filter (108) applies to the deviation ΔL. In addition, in FIG. 3, the characteristic function f' corresponding to the case where the first control route C1 is selected is indicated by a dashed line for comparison (since the deviation ΔL is input as is to the PI controller (106) in the first control route C1, it is practically equivalent to having a characteristic function f' that is a first-order 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 that of the characteristic function f' in the minus-side region (i.e., ΔL<0). More specifically, as illustrated in Fig. 3, the characteristic function f has a linear characteristic with a slope of "1" in the plus-side region (ΔL≤0) and the minus-side region below a threshold value (ΔL<ΔL1), and has a slope of "0" and a dead band characteristic in the minus-side region (ΔL1≤ΔL<0) of a predetermined value ΔL1 or higher.

The PI controller (106) outputs a steam valve opening command value corresponding to the deviation ΔL input to the PI controller (106), thereby feedback-controlling the opening of the steam valve (8). When the first control route C1 is selected by the switch (104), the PI controller (106) outputs a 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 filtering processing is performed by the filter (108). In the filter (108), as described above with reference to FIG. 3, the deviation ΔL is output to be larger than normal in the minus-side region where the generator output L is larger than the load command value Ld, thereby suppressing the throttling operation of the steam valve (8). This means that, as described in detail later, when the load command value increases and multiple throttling controls are executed, the throttling operation of the steam valve (8) is suppressed when the deviation ΔL becomes a minus side region.

Meanwhile, in the steam generator control unit (120), the steam pressure setpoint 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 setpoint 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. To the output signal output from the PI controller (124), the load command value Ld is added as a feedforward component in the adder (126), thereby improving the load followability of the steam generator (2). Such a control signal of the steam generator (2) is output to the steam generator (2), which is the control target, as the feedwater demand signal Sw and the fuel demand signal Sf, which are control parameters of the steam generator (2).

<Multiple Throttling Control>

Continuing, a multiple throttling control in a power plant (1) having the above configuration is described. Multiple throttling control is a control for increasing the output of a generator (5) by reducing the opening of multiple regulating valves (23) and bleed valves (28). Fig. 4 is a flow chart showing a mechanism for increasing generator output by multiple throttling control for each process.

In the multiple throttling control, first, the opening of the multiple regulating valves (23) is operated to decrease (step S100). Such throttling operation of the multiple regulating valves (23) may be performed manually by an operator, or may be performed automatically by detecting a trigger signal for control initiation with the control device (100) and transmitting a control signal to the multiple regulating valves (23) from the control device (100).

When the opening degree of the plural control valve (23) decreases, the plural flow rate flowing through the plural line (22) located downstream from the plural control valve (23) decreases (step S101). Here, in the plural heaters (24) provided on the plural lines (22), as described above, the opening degree of the bleed valve (28) is controlled to correspond to the plural flow rate flowing through the plural lines (22), thereby introducing bleed of the flow rate required for heat exchange with the plural. Therefore, when the plural flow rate in the plural lines (22) decreases as in step S101, the opening degree of the bleed valve (28) is also controlled to decrease accordingly (step S102). In addition, when the opening degree of the bleed valve (28) decreases, the bleed 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 multiple throttling control in this way, the output of the generator (5) can be increased. However, the effect of increasing the generator output by the multiple throttling control is not permanent, but is temporary for a certain limited period after the multiple throttling control is started. This is because the multiple flow rate decreases due to the multiple throttling control, and the deaerator level in the deaerator (25) decreases, making it impossible to continue supplying water to the steam generator (2). As a result, the effect of increasing the generator output by the multiple throttling control decreases after the temporary period has elapsed.

In contrast, in one embodiment of the present disclosure, when the load command value Ld increases, in order to permanently increase the generator output L, the load command value Ld is increased (for example, by manual operation by an operator of the power plant (1)), and by selecting the second control route C2 when the multiple throttling control is executed, the throttling of the steam valve (8) is suppressed during the multiple throttling, thereby making it easy to obtain the effect of increasing the generator output by the multiple throttling control. In the second control route C2, by performing filtering processing by the filter (108), the deviation ΔL is set to be larger in the minus-side region than in the first control route C1. As a result, since the steam valve (8) is difficult to narrow when the multiple throttling control is executed, the effect of increasing the generator output becomes easy to obtain.

<Spillover Control>

A spillover control for appropriately maintaining the plural level in the first plural tank (12) by continuously exchanging the plural generated in the plural generator (10) between the first plural tank (12) and the second plural tank (16) is described.

Spillover control is performed by adjusting the opening degree of the plural control valve (23) as described above in normal times when the plural throttling control is not executed. That is, by adjusting the opening degree of the plural control valve (23), the plural supply amount to the plural line (22) is changed, thereby appropriately managing the plural level stored in the first plural tank (12). On the other hand, when the plural throttling control is executed, the plural control valve (23) is narrowed regardless of the plural level of the first plural tank (12) in order to increase the generator output L, so that spillover control is performed by adjusting the opening degree of the plural discharge valve (27) provided between the first plural tank (12) and the second plural tank (16).

Fig. 5 is a control flow chart regarding a plurality of discharge valves (27) in spillover control. In spillover control, a plurality of levels F detected by a plurality of level sensors (not shown) installed in a first plurality of tanks (12) and an appropriate plurality of level target value F* corresponding to the first plurality of tanks (12) are input to a deviation calculation unit (130), whereby a deviation ΔF is calculated. The deviation ΔF is input to a PI controller (132), whereby a plurality of discharge valve opening command value corresponding to the deviation ΔF is output. Thereby, feedback control is performed so that the plurality of levels become the plurality of level target value F* (i.e., so that the deviation ΔF becomes zero).

Here, the multiple-level target value F* is set by the multiple-level target value setting unit (134). In the multiple-level target value setting unit (134), the multiple-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). The addition target value F*2 is selected as either “0” or “α (a number greater than zero)” based on whether or not the multiple throttling control is being executed. Specifically, when the multiple throttling control is being executed, the switch (138) selects “0” as the addition target value F*2. In this case, the multiple-level target value F* becomes F*1+F*2(=0)=F*1. On the other hand, in the normal time when the multiple throttling control is not being executed, the switch (138) selects “α” as the addition target value F*2. In this case, the multiple level target value F* becomes F*1+F*2=F*1+α.

In this way, the multiple level target value F* is set to be larger by α when the multiple throttling control is not implemented compared to when the multiple throttling control is implemented. As a result, when the multiple throttling control is not implemented, the opening of the multiple discharge valve (27) is fixed small (preferably set to a completely closed state), and the multiple discharge valve (27) is not involved in spillover control. On the other hand, when the multiple throttling control is implemented, since α is not added to the multiple level target value F*, the opening of the multiple discharge valve (27) is feedback controlled so as to become the multiple level target value F*. As a result, even when the multiple regulating valve (23) is in a narrowed state by the multiple throttling control, it becomes possible to implement spillover control by adjusting the opening of the multiple discharge valve (27).

<Load response control>

Continuing, the load response control of the power generation plant (1) in the case where the load command value Ld for the power generation 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 and the output trend of the power generation plant (1) in relation to each other during the load response control. Here, as shown in Fig. 7, the case where the load command value Ld, which was initially at the first steady value L1, monotonically increases from time t1 to time t2 and fluctuates to increase to the second steady value L2 is described as an example.

First, the control device (100) monitors the load command value Ld input to the power generation plant (step S200) and determines whether the load command value Ld has increased (step S201). The determination in step S201 is performed based on, for example, whether the amount of change in the load command value Ld with respect to the first steady value L1 before time t1 has reached a threshold for determination. In one aspect of the present disclosure, for example, the control device (100) determines that the load command value Ld has increased when the rate of change in the load command value Ld (the amount of change in the load command value Ld in a predetermined period of time) exceeds the threshold for determination.

If it is determined that the load command value Ld has increased (step S201: "Yes"), multiple throttling control is performed (step S202). Multiple throttling control is performed by reducing the openings of the multiple regulating valves (23) and the bleed valves (28) as described above. Such throttling operation of the multiple regulating valves (23) may be performed manually by an operator, for example, or may be performed automatically by transmitting a control signal from the control device (100) to the multiple regulating valves (23) and the bleed valves (28). When multiple throttling control is performed in step S202, the output of the generator (5) temporarily increases as described above with reference to FIG. 4.

The control device (100) then performs load increase control of the steam generator (2) (step S203). Since the multiple throttling control is limited to a temporary increase in the output of the generator (5) as described above, by performing the load increase control of the steam generator (2), it is possible to follow the increase in the load command value Ld even after the effect of increasing the output by the multiple throttling control has decreased.

In addition, although step S203 is described to be performed after step S202 in terms of formal circumstances in Fig. 6, steps S202 and S203 may be performed simultaneously. In other words, multiple throttling control and load increase control may be performed simultaneously. As described above, since load increase control has lower responsiveness than multiple throttling control (since the initial response when the load command value Ld starts changing is slow), it is preferable to perform them simultaneously. In addition, within the scope of the concept, it is not denied that step S203 is performed after step S202 as shown in Fig. 6, or that step S203 is performed before step S202.

Such multiple throttling control and load increase control continue until the load command value Ld reaches the second steady value L2 (step S204: "Yes"), and when the output of the power plant (1) sufficiently converges to the second steady value L2 (step S205: "Yes"), it ends (END).

Here, in Fig. 7, as comparative examples, a case where only multiple throttling control is performed from time t1 (Comparative Example 1) and a case where only load increase control of the steam generator (2) is performed from time t1 without performing multiple throttling control (Comparative Example 2). In Comparative Example 1, since only multiple throttling control is performed, the responsiveness is better than in Comparative Example 2, and the output of the power plant (1) can be temporarily increased immediately after time t1, but the output increase effect by such multiple throttling control does not continue permanently as described above. In Comparative Example 2, only 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 pulverizing coal in a coal mill, so the time lag until the pulverized coal is fed into the furnace and reflected in the output is large, and the responsiveness is poor. In this embodiment, with respect to these comparative examples, by combining multiple throttling control and load increase control when the load command value Ld increases, it is shown that good responsiveness to changes in the load command value Ld is obtained, and the time until the output of the power generation plant (1) converges to the second steady value L2 is shortened.

In addition, in the multiple throttling control, as described above, the openings of the multiple regulating valves (23) and the bleed valves (28) are narrowed, but the rate of change in the openings at that time is set based on the rate of change in the load command value Ld acquired in step S200. The amount of change in the generator output L by the multiple throttling control depends on the rate of change in the openings of the multiple regulating valves (23) and the bleed valves (28). Therefore, by controlling the rate of change in the openings of the multiple regulating valves (23) and the bleed valves (28) when the multiple throttling control is executed, it is possible to suppress the generator output L from becoming excessively deviated from the load command value Ld.

In the multiple throttling control of the first comparative example of Fig. 7, since the opening change rates of the multiple regulating valves (23) and the bleed valves (28) are arbitrarily controlled in this way, the generator output L increases rapidly immediately after time t1, and the deviation from the load command value Ld becomes large. In contrast, in the present embodiment, by setting the opening change rates of the multiple regulating valves (23) and the bleed valves (28) based on the change rate of the load command value Ld, the increase in the generator output L immediately after time t1 is appropriately suppressed compared to the first comparative example, and the deviation from the load command value Ld is reduced. This shows that the generator output L by the multiple throttling control can be adjusted to correspond to the change in the load command value Ld, and good followability is obtained.

As described above, according to at least one aspect of the present disclosure, when a load increase is requested, a control device for a power generation plant, a power generation plant, and a control method for a power generation plant can be provided, which can follow the output of the power generation plant with good responsiveness and within an appropriate range with respect to a load command value.

In addition, within the scope that does not deviate from the spirit of the present disclosure, it is appropriate to replace the components in the above-described embodiments with well-known components, and the above-described embodiments may also be appropriately combined.

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

(1) A control device of a power plant according to one aspect of the present disclosure,

A steam generator configured to generate steam (e.g., the steam generator (2) of the above embodiment),

A turbine configured to be driven using the above steam (e.g., the turbine (6) of the above embodiment),

A condenser (e.g., the condenser (10) of the above embodiment) configured to generate condensate by condensing the steam that has completed work in the above turbine,

A plurality of regulating valves configured to be able to adjust the supply amount to the plurality of steam generators (e.g., the plurality of regulating valves (23) of the above embodiment),

A heater configured to heat the plurality using the exhaust from the turbine (e.g., the heater (24) of the embodiment above),

A bleed valve configured to adjust the flow rate of the above bleed (e.g., a bleed valve (28) of the above embodiment)

A control device (e.g., a control device (100) of the above embodiment) of a power generation plant (e.g., a power generation plant (1) of the above embodiment) equipped with a

When the load command value for the above power generation plant increases, it is configured to perform multiple throttling control to narrow the opening degree of the above multiple control valves and load increase control to increase the load of the above steam generator.

In the above multiple throttling control, the openings of the multiple regulating valves and the bleed valve are configured to be controlled at an opening change rate set based on a change rate of the load command value.

According to the aspect of the above (1), when the load command value for the power plant increases, by performing multiple throttling controls that narrow the opening degrees of the multiple regulating valves in addition to the load increase control, the output of the power plant can be increased with good responsiveness. Thereby, good responsiveness is obtained compared to the case where only the load increase control, which requires relatively long response time, is performed. Furthermore, by performing multiple throttling controls and load increase controls, the output of the power plant can be increased up to the target load even when the change in the load command value is large. By performing multiple throttling controls and load increase controls in this way in combination, the output of the power plant can be followed with good responsiveness with respect to the increase in the load command value.

In addition, in the multiple throttling control, the openings of the multiple regulating valves and the bleed valves are 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 multiple throttling control can be adjusted to correspond to the change in the load command value. As a result, when the multiple throttling control is performed, the generator output is suppressed from greatly exceeding the load command value and deviating, and good followability with respect to the load command value is obtained.

(2) In another aspect, in the aspect of (1) above,

The above power plant further comprises a steam valve (e.g., steam valve (8) of the above embodiment) for controlling the amount of steam supplied to the turbine,

During execution of the above multiple throttling controls, a decrease in the opening command value for the steam valve caused by execution of the above multiple throttling controls is suppressed (for example, in the above embodiment, the deviation ΔL input to the PI controller (106) that outputs the steam valve opening command value is corrected by the filter (108)).

According to the aspect of the above (2), when multiple throttling control is performed, the decrease in the opening degree of the steam valve is suppressed. Accordingly, when the generator output temporarily increases due to the multiple throttling control, the opening degree of the steam valve is reduced so as to reduce the generator output exceeding the target output, thereby suppressing the decrease in the generator output. As a result, the effect of increasing the generator output by the multiple throttling control can be obtained more accurately.

(3) In another aspect, in the aspect of (1) above,

A steam valve control unit (e.g., a steam valve control unit (110) of the embodiment) configured 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.

The above steam valve control unit is configured to control the opening degree of the steam valve for the deviation to become larger during execution of the multiple throttling control when the load command value increases and the deviation is in the minus side region compared to when the multiple throttling is not executed (for example, in the above embodiment, the filter (108) has the characteristics shown in Fig. 3).

According to the aspect of the above (3), when the deviation is in the minus side range due to the implementation of multiple throttling control, the steam valve opening is controlled to be larger than when the multiple throttling control is not implemented. As a result, the decrease in the steam valve opening when the multiple throttling control is implemented is suppressed, so that the effect of increasing the generator output by the multiple throttling control can be obtained more accurately.

(4) In another aspect, in the aspect of (3) above,

The above steam valve control unit is configured to control the opening degree of the steam valve to be constant with respect to the deviation when the load command value increases and, during execution of the multiple throttling control, the deviation is in a minus-side region of a predetermined value or more (for example, in the above embodiment, the filter (108) has the characteristics shown in Fig. 3).

According to the aspect of the above (4), when the deviation is in the minus side range exceeding a predetermined value, the opening degree of the steam valve is suppressed to be constant, so that the effect of increasing the generator output by multiple throttling control can be obtained more accurately.

(5) In another aspect, in one aspect of any of (1) to (4) above,

The above power plant,

A plurality of discharge lines configured to discharge the plurality of stored in the plurality of tanks (e.g., the plurality of discharge lines (14) of the embodiment above),

A plurality of discharge valves configured to be able to adjust the plurality of flow rates in the plurality of discharge lines (e.g., the plurality of discharge valves (27) of the embodiment above)

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During execution of the above-described multiple throttling control, the opening degree of the multiple discharge valves is adjusted to control the multiple levels in the condenser (for example, in the above-described embodiment, the multiple discharge valves (27) are controlled to adjust the multiple levels during the multiple throttling control).

According to the aspect of the above (5), the plural levels can be appropriately managed by controlling the opening of the plural discharge valves while throttling the plural regulating valves by the plural throttling control.

(6) In another aspect, in one aspect of any of (1) to (5) above,

The above multiple throttling control and the above load increase control are performed simultaneously.

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

(7) In another aspect, in one aspect of any of (1) to (6) above,

When the above load command value increases by 5% or more, the multiple throttling control is configured to be executed.

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

(8) In another aspect, in one aspect of any of (1) to (7) above,

The above load command value is input to the power generation plant from the central power supply command room according to the supply and demand status of the power system.

According to the aspect of (8) above, the output of the power generation plant can be appropriately followed with good responsiveness according to the supply and demand status of the power system.

(9) In another aspect, in one aspect of any of (1) to (8),

The above steam generator is a coal-fired boiler that uses coal as fuel.

According to the aspect of the above (9), since there is a process of crushing coal with a coal mill, even in a power plant that uses a coal-fired boiler as a steam generator, which has low responsiveness to a load command value by operation control, by performing a combination of multiple throttling control and load increase control, the output of the power plant can be followed with good responsiveness to an increase in the load command value.

(10) A power plant according to one aspect of the present disclosure,

A control device having one aspect of any of the above (1) to (9).

According to the aspect of the above (10), by performing a combination of multiple throttling control and load increase control, the output of the power plant can be followed with good responsiveness to an increase in the load command value.

(11) A method for controlling a power plant according to one aspect of the present disclosure,

A steam generator configured to generate steam (e.g., the steam generator (2) of the above embodiment),

A turbine configured to be driven using the above steam (e.g., the turbine (6) of the above embodiment),

A condenser (e.g., a condenser control valve (23) of the above embodiment) configured to generate condensate by condensing the steam that has completed work in the above turbine,

A plurality of regulating valves configured to be able to adjust the supply amount to the plurality of steam generators (e.g., the plurality of regulating valves (23) of the above embodiment),

A heater configured to heat the plurality using the exhaust from the turbine (e.g., the heater (24) of the embodiment above),

A bleed valve configured to adjust the flow rate of the above bleed (e.g., a bleed valve (28) of the above embodiment)

A control method for a power plant (e.g., the power plant (1) of the above embodiment) equipped with a

When the load command value for the above power generation plant increases, a multiple throttling control is performed to narrow the opening of the multiple control valves, and a load increase control is performed to increase the load of the steam generator.

In the above multiple throttling control, the openings of the multiple regulating valves and the bleed valve are controlled based on the opening change rate set based on the change rate of the load command value.

According to the aspect of the above (11), when the load command value for the power plant increases, by performing multiple throttling controls that narrow the opening degrees of the multiple regulating valves in addition to the load increase control, the output of the power plant can be increased with good responsiveness. Thereby, good responsiveness is obtained compared to the case where only the load increase control, which requires relatively long response time, is performed. Furthermore, by performing multiple throttling controls and load increase controls, the output of the power plant can be increased up to the target load even when the change in the load command value is large. By performing multiple throttling controls and load increase controls in this way, the output of the power plant can be followed with good responsiveness with respect to the increase in the load command value.

In addition, in the multiple throttling control, the openings of the multiple regulating valves and the bleed valves are 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 multiple throttling control can be adjusted to correspond to the change in the load command value. As a result, when the multiple throttling control is performed, the generator output is suppressed from greatly exceeding the load command value and deviating, and good followability with respect to the load command value is obtained.

1: Power plant
2: Steam generator
3: Output shaft
4: Steam supply line
5: Generator
6: Turbine
8: Steam valve
10: Revenge
12: 1st Revenge Tank
14: Multiple discharge lines
16: 2nd Revenge Tank
22: Multiple lines
23: Multiple control valve
24: Heater
25: Degassing
26: Cardinal Line
27: Multiple discharge valve
28: Cardiac valve
100: Control device
102: Deviation operator
104: Switch
106: PI controller
108: Filter
110: Steam valve control
120: Steam generator control unit
122: Deviation operator
124: PI controller
126: Adder
130: Deviation operation unit
132: PI controller
134: Multiple level target value setting section
136: Adder
138: Switch

Claims (11)

A steam generator configured to generate steam,
A generator connected to a turbine configured to be driven using said steam,
A condenser configured to generate condensate by condensing the steam that has completed work in the turbine;
A plurality of regulating valves configured to be capable of adjusting the supply amount to the plurality of steam generators,
A heater configured to heat the plural by using the exhaust from the turbine;
A bleed valve configured to be able to adjust the flow rate of the above bleeder
It is a control device for a power plant equipped with
When the load command value for the above power generation plant increases, it is configured to perform multiple throttling control to narrow the opening of the above plural control valve and the above bleed valve, and load increase control to increase the load of the above steam generator.
A control device for a power plant configured such that, in the above-described multiple throttling control, the openings of the multiple regulating valves and the bleed valve are controlled at an opening change rate set based on a change rate of the load command value so that the amount of deviation of the output of the generator from the load command value becomes a predetermined value or less. In the first paragraph,
The above power generation plant further comprises a steam valve for controlling the amount of steam supplied to the turbine,
A control device of a power plant, configured to suppress a decrease in an opening reference value for the steam valve due to execution of the above multiple throttling controls during execution of the above multiple throttling controls. In the second paragraph,
A steam valve control unit configured to control the opening degree of the steam valve for adjusting the flow rate of steam supplied from the steam generator to the turbine based on the deviation between the output of the generator and the load command value,
A control device of a power plant, wherein the steam valve control unit is configured to control the opening degree of the steam valve for the deviation to increase when the load command value increases and the deviation is in the minus side range during execution of the multiple throttling control compared to when the multiple throttling is not executed. In the third paragraph,
A control device for a power plant, wherein the steam valve control unit is configured to control the opening degree of the steam valve to be constant for the deviation when the load command value increases and, during execution of the multiple throttling control, the deviation is in a minus-side range of a predetermined value or more. In any one of claims 1 to 4,
The above power plant,
A plural discharge line configured to discharge the plural stored in the plural device,
A plurality of discharge valves configured to be capable of adjusting the plurality of flow rates in the plurality of discharge lines.
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A control device of a power plant, configured to control the plural levels in the condenser by adjusting the opening degree of the plural discharge valves during execution of the plural throttling control. In any one of claims 1 to 4,
A control device of a power generation plant, wherein the above-mentioned multiple throttling control and the above-mentioned load increase control are performed simultaneously. In any one of claims 1 to 4,
A control device of a power plant configured to execute the multiple throttling control when the above load command value increases by 5% or more. In any one of claims 1 to 4,
The above load command value is a control device of a power generation plant, which is input to the power generation plant from the central power supply command room according to the supply and demand status of the power system. In any one of claims 1 to 4,
The above steam generator is a control device of a power plant, which is a coal-fired boiler using coal as fuel. A power plant having a control device as described in any one of claims 1 to 4. A steam generator configured to generate steam,
A turbine configured to be driven using the above steam,
A condenser configured to generate condensate by condensing the steam that has completed work in the turbine;
A plurality of regulating valves configured to be capable of adjusting the supply amount to the plurality of steam generators,
A heater configured to heat the plural by using the exhaust from the turbine;
A bleed valve configured to be able to adjust the flow rate of the above bleeder
A method for controlling a power plant equipped with
When the load command value for the above power plant increases, a multiple throttling control is performed to narrow the opening of the multiple control valve and the bleed valve, and a load increase control is performed to increase the load of the steam generator.
A control method for a power plant, wherein in the above-described multiple throttling control, the openings of the multiple regulating valves and the bleed valve are controlled by an opening change rate set based on a change rate of the load command value so that the amount of deviation of the generator output from the load command value becomes a predetermined value or less.

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