JP7303696B2 - POWER PLANT CONTROL DEVICE, POWER PLANT, AND POWER PLANT CONTROL METHOD - Google Patents

Description

Application of Article 30, Paragraph 2 of the Patent Act Publication date: May 18, 2019 Publication location: The Thermal and Nuclear Power Engineering Society University Lecture (first half of 2019) The Thermal and Nuclear Power Engineering Society Headquarters Meeting Room (Port of Tokyo 2-31-15 Shiba, Hokkai Shiba Building 5F)

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

A power system is required to stably supply power in accordance with power demand. In recent years, the introduction of renewable energy is progressing with the rise of environmental awareness. ) is expected to play a role in the stable supply of electric power by improving additional controllability.

For example, Patent Literature 1 discloses a boiler control device capable of controlling power generation output by controlling a boiler that generates steam for driving a turbine in a thermal power plant or the like. In this document, the power generation output is adjusted by a steam valve provided in the main steam path through which the generated steam of the boiler flows, and the fuel supplied to the boiler controls the steam pressure in the main steam path to a predetermined target steam pressure. are doing.

JP 2009-85442 A

In order to maximize plant efficiency, such a system may be operated as a full transformer plant in which the opening of the steam valves is controlled to the maximum opening (100%). In this case, although good plant efficiency can be obtained, when the load command value for the power plant changes, it is difficult to quickly follow the change in the load command value in the power generation output. Specifically, in a complete transformation plant, the opening of the steam valve is basically controlled to the maximum opening (100%). The power generation output cannot be adjusted, and there is no choice but to rely on low-response control such as the amount of fuel supplied to the boiler. Especially in coal-fired boilers that use coal as fuel, there is a process of pulverizing coal with a coal pulverizer, so it takes time for the pulverized coal to be put into the furnace, and response to changes in the load command value is poor. It tends to become weaker.

In this way, in power plants, not only plant efficiency but also other performance such as followability to fluctuations in the load command value may be required depending on the situation. For example, in a power system where the introduction of renewable energy has progressed, the load demand for other power plants increases significantly during the evening hours when the output of photovoltaic power generation declines and power demand increases. I have something to do. Therefore, other power plants are sometimes required to follow up the plant output in order to cope with such an increase in load demand.

At least one aspect of the present disclosure has been made in view of the above circumstances, and includes a control device for a power plant that can follow the output of the power plant with good responsiveness when the load demand increases, a power plant, and a power plant. The object is to provide a control method.

In order to solve the above problems, a control device for a power plant according to an aspect of the present disclosure includes:
a steam generator configured to generate steam;
a generator coupled to a turbine configured to be driven using the steam;
a steam valve for controlling the amount of steam supplied to the turbine;
A control device for a power plant comprising
a steam valve control unit configured to control the steam valve so that the output of the generator becomes a load command value for the power plant;
a steam generator control unit configured to control the steam generator such that the steam pressure of the steam generator reaches a target pressure value;
a control mode selection unit configured to be able to select either the normal mode or the load change corresponding mode;
A second target pressure value obtained by adding a bias value to the first target pressure value corresponding to the normal mode is set as the target pressure value when the load change corresponding mode is selected by the control mode selection unit. A target pressure value correction unit configured as
Prepare.

In order to solve the above problems, the power plant control method according to one aspect of the present disclosure includes:
a steam generator configured to generate steam;
a generator coupled to a turbine configured to be driven using the steam;
a steam valve for controlling the amount of steam supplied to the turbine;
A control method for a power plant comprising
a steam valve control step of controlling the steam valve so that the output of the generator becomes a load command value for the power plant;
a steam generator control step of controlling the steam generator such that the steam pressure of the steam generator reaches a target pressure value;
a control mode selection step of selecting either the normal mode or the load change corresponding mode;
with
In the load change corresponding mode, a second target pressure value obtained by adding a bias value to the first target pressure value corresponding to the normal mode is set as the target pressure value.

According to at least one aspect of the present disclosure, it is possible to provide a control device for a power plant, a power plant, and a control method for the power plant that can follow the output of the power plant with good responsiveness when a load increase request is made.

1 is an overall configuration diagram of a power plant according to one aspect of the present disclosure; FIG. FIG. 2 is a control flow diagram of the control device in FIG. 1; FIG. 10 is a diagram showing the load dependence of the steam valve opening degree in the normal mode and the load change corresponding mode when the load command value is in a steady state; 4 is a timing chart showing changes in generator output, load command value, steam valve opening command value, and steam generator control value in normal mode. 4 is a timing chart showing changes in generator output, load command value, steam valve opening command value, and steam generator control value in a load change corresponding mode. A first target pressure value and a second target pressure value corresponding to the normal mode and the load change corresponding mode output from the target pressure value correction unit are shown. It is a modification of FIG.

Several embodiments of the present invention will now 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 positions, and the like of components described in the following embodiments are not intended to limit the scope of the present invention, but merely illustrative examples.

<Overall configuration of the power plant>
FIG. 1 is an overall configuration diagram of a power plant 1 according to one aspect of the present disclosure. The power plant 1 includes a steam generator 2 , a turbine 4 and a generator 6 . The steam generated by the steam generator 2 is supplied to the turbine 4 to drive the turbine 4 . A generator is connected to the output shaft of the turbine 4, and the rotational energy of the turbine 4 is converted into electrical energy. The electrical energy generated by the generator 6 is supplied to an electric power system (not shown) through a predetermined route.

The steam generator 2 is configured to generate steam. The steam generator 2 is, for example, a boiler device that can generate steam from feed water using heat generated by burning fuel. More specifically, the boiler device is a conventional boiler capable of generating steam by pulverizing coal with a coal pulverizer (not shown) and combusting the pulverized coal in a furnace. The boiler device may be a drum boiler or a once-through boiler.

Steam generated by the steam generator 2 is supplied to the turbine 4 via a steam supply line 8 . The turbine 4 is rotationally driven by the high-temperature, high-pressure steam generated by the steam generator 2 . A steam valve 10 (main steam valve) for adjusting the flow rate of steam supplied from the steam generator 2 to the turbine 4 is installed in the steam supply line 8 that connects the steam generator 2 and the turbine 4 . The degree of opening of the steam valve 10 can be controlled by a control signal from the controller 100, which will be described later.

The steam that has finished work in the turbine 4 is condensed by, for example, a condenser (not shown) arranged downstream of the turbine 4, and then constitutes a circulation path that feeds the steam generator 2 again. .

A control device 100 is a control unit of the power plant 1 and has a hardware configuration including 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 a control method according to at least one aspect of the present disclosure in such a hardware configuration. configured as possible.

The control device 100 is configured to be able to comprehensively control the power plant 1 by transmitting and receiving control signals to and from each component of the power plant 1 . Such control of the power plant 1 is performed based on a load command value for the power plant 1 that the controller 100 obtains from the outside. The load command value is a command value relating to the load required for the power plant 1, and is determined according to the supply and demand state in the power system, for example.

<Power plant control>
Next, 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. 2 shows the inside of the control device 100 as a functional block diagram, and the control device 100 includes a steam valve control section 110, a steam generator control section 120, and a control mode selection section . The steam valve control unit 110 is a functional block for outputting an opening degree command value for the steam valve 10 in response to an input signal. Functional block for outputting control parameters (eg water demand signal and fuel demand signal). The control mode selection unit 130 is a functional block for selecting a specific control mode from multiple candidates prepared in advance as the control mode of the power plant 1 .

A generator output L, a load command value Ld, a target pressure value Ps, and a steam pressure value P are input to the control device 100, respectively. The generator output L can be obtained based on the detected value of the power output from the generator 6 . The load command value Ld is a command value that is input from the outside to the power plant 1 (for example, it is received from the central power supply command room according to the power supply and demand state of the power system). The target pressure value Ps is a target value relating to the steam pressure of the steam generator 2, and is appropriately corrected by a target pressure value corrector 140, which will be described later. The steam pressure value P can be obtained based on the detected value of the steam pressure of the steam generator 2, and can be obtained, for example, by a pressure sensor installed at the outlet of the steam generator 2 on the upstream side of the steam valve 10. be.

In the steam valve control section 110 , first, the generator output L and the load command value Ld are input to the deviation calculation section 112 . A deviation calculator 112 calculates and outputs a deviation ΔL (=Ld−L) between the generator output L and the load command value Ld. The deviation ΔL output from the deviation calculator 112 is input to the PI controller 114 . The PI controller 114 generates a steam valve opening command value corresponding to the deviation ΔL and outputs it to the steam valve 10 . Thereby, the opening degree of the steam valve 10 is feedback-controlled so that the deviation ΔL is minimized (that is, so that the generator output L becomes the load command value Ld).

In the steam generator control section 120 , the target pressure value Ps is appropriately corrected by the target pressure value correction section 140 and then input to the deviation calculation section 122 together with the steam pressure value P. The deviation calculator 122 outputs a deviation ΔP (=Ps−P) between the corrected target pressure value Ps and the steam pressure value P. The deviation ΔP output from the deviation calculator 122 is input to the PI controller 124 . PI controller 124 outputs an output signal corresponding to deviation ΔP. The load command value Ld is added to the output signal output from the PI controller 124 in the adder 126, and a steam generator control value, which is a control signal for the steam generator 2, is output. By adding the load command value Ld as a feedforward component to the output signal of the PI controller 124 in this way, the load followability of the steam generator 2 is improved. The steam generator control values output in this way include, for example, a water supply demand signal and a fuel demand signal corresponding to the water supply amount and the fuel supply amount, which are the control parameters of the steam generator 2 .

The control mode selector 130 selects a control mode for the power plant 1 . The power plant 1 is provided with a plurality of selectable control modes. In this aspect, the control modes of the power plant 1 include at least a normal mode and a load change handling mode. The normal mode is a control mode corresponding to normal operation of the power plant 1 . The load change corresponding mode is a control mode in which the output response when the load command value Ld fluctuates is improved compared to the normal mode.

Correction of the target pressure value Ps in the target pressure value correction unit 140 is performed based on the selection result of the control mode in the control mode selection unit 130 . Specifically, the target pressure value correction unit 140 selects either “0” or “α (>0)” as the bias value for the target pressure value Ps according to the selection result of the control mode in the control mode selection unit 130. By adding one of them, it is possible to switch between the first target pressure value Ps1 and the second target pressure value Ps2 corresponding to the normal mode and the load change corresponding mode, respectively.

When the control mode selection unit 130 selects the normal mode, the target pressure value correction unit 140 adds the bias value "0" to the target pressure value Ps to obtain the first target pressure value Ps1 (=Ps+0). Output to the deviation calculation unit 122 . The first target pressure value Ps1 is set so that the opening of the steam valve 10 becomes the first opening, which is the maximum opening (100%), in a steady state when the load command value Ld is constant. That is, in the normal mode, the steam valve 10 is fully opened to maximize the plant efficiency (that is, in the normal mode, the power plant 1 is controlled as a so-called complete transformer plant).

On the other hand, when the control mode selection unit 130 selects the load change corresponding mode, the target pressure value correction unit 140 adds the bias value "α" to the target pressure value Ps to obtain the second target pressure value Ps2 ( =Ps+α) to the deviation calculator 122 . In other words, the second target pressure value Ps2 is set higher than the first target pressure value Ps1. Therefore, in the load change corresponding mode, the steam generator 2 is controlled to a higher output side than in the normal mode. As a result, the generator output L input to the steam valve control unit 110 increases, and in order to bring the generator output L closer to the load command value Ld, the opening degree of the steam valve 10 becomes the second opening degree smaller than the normal mode. controlled as

FIG. 3 is a diagram showing the load dependence of the steam valve opening degree in the normal mode and the load change corresponding mode when the load command value is in a steady state. As shown in FIG. 3, in the normal mode, the degree of opening of the steam valve 10 is controlled to the first degree of opening, which is the maximum degree of opening (100%). Thus, in the normal mode, when the load command value Ld is in a steady state, the steam valve 10 is basically controlled to be in a fully open state, thereby achieving good plant efficiency. On the other hand, when the load command value Ld fluctuates, the opening of the steam valve 10 has already reached the fully open state in the normal mode, so the opening of the steam valve 10 is controlled to reduce the output of the power plant 1 to the load. There is no room to follow the command value. Therefore, in the normal mode, it is necessary to control the operating state of the steam generator 2 by the steam generator control unit 120 so that the output of the power plant 1 follows the load command value Ld. However, since the output of the steam generator 2 has a time lag with respect to fluctuations in the load command value Ld, it tends to be difficult to obtain good responsiveness.

Here, FIG. 4 is a timing chart showing changes in the generator output L, the load command value Ld, the steam valve opening command value, and the steam generator control value in the normal mode. In FIG. 4, the load command value Ld fluctuates so as to increase from the first steady state Ld1 to the second steady state Ld2 at time t1. In this case, since the steam valve opening is already at the first opening, which is the maximum opening (100%), at time t1, there is no room for variation following the load command value Ld. Therefore, in the normal mode, when the command value of the steam generator control value changes at time t1, the variation of the load command value Ld is dealt with by controlling the operation of the steam generator 2 with relatively low responsiveness. As a result, in the normal mode, it takes time for the generator output L to converge to the target second steady state L2 at time t2.

In the load change support mode, the opening degree of the steam valve 10 is controlled to a second opening degree that is smaller than the first opening degree (100%). FIG. 5 is a timing chart showing changes in the generator output L, the load command value Ld, the steam valve opening command value, and the steam generator control value in the load change corresponding mode. In FIG. 5, as in FIG. 4, the load command value Ld fluctuates so as to increase from the first steady state Ld1 to the second steady state Ld2 at time t1. In this case, since the steam valve opening command value is at the second opening smaller than the maximum opening (100%) at time t1, there is still room for variation following the load command value Ld. Therefore, in the load change corresponding mode, by adjusting the opening degree of the steam valve 10 corresponding to the load command value Ld (by increasing the opening degree of the steam valve 10), the opening of the steam valve 10 with excellent responsiveness can be achieved. Speed control can follow load fluctuations. As a result, in the load change corresponding mode, changes in the load command value Ld can be followed with better responsiveness than in the normal mode, and the generator output L can quickly converge to the second steady state L2 at time t3. .

In the load change corresponding mode, the steam valve 10 is controlled to the second degree of opening smaller than the fully open state in a steady state where there is no change in the load command value Ld, so the plant efficiency is considerably reduced compared to the normal mode. It is necessary to pay attention to

The control mode selector 130 selects one of the normal mode and the load change mode. In FIG. 2, the control mode selection unit 130 switches the target pressure value corresponding to each control mode by transmitting a control mode selection signal to the target pressure value correction unit 140 in accordance with the control mode selection result. configured to do FIG. 6 shows the first target pressure value Ps1 and the second target pressure value Ps2 that are output from the target pressure value correction unit 140 and correspond to the normal mode and the load change corresponding mode.

The bias value α is selected according to the second degree of opening of the steam valve 10 when the load change corresponding mode is selected.

<Control mode switching control>
Selection of the control mode by the control mode selection unit 130 may be automatically performed according to the possibility of variation of the load command value Ld. FIG. 7 is a modification of FIG. This modification differs from FIG. 2 in that it includes a load variation estimator 150 configured to estimate the possibility of variation in the load command value Ld. Load change estimator 150 estimates the possibility of future change in load command value Ld. The estimation result of the load fluctuation estimation unit 150 is sent to the control mode selection unit 130, and the control mode selection unit 130 automatically selects the control mode of the power plant 1 based on the received estimation result.

For example, when the load change estimation unit 150 determines that the load command value Ld is unlikely to change, the control mode selection unit 130 selects the normal mode as the control mode. This enables efficient plant operation with priority given to plant efficiency. On the other hand, when load change estimating section 150 determines that load command value Ld is highly likely to change, control mode selecting section 130 selects the load change corresponding mode as the control mode. Accordingly, when the load command value Ld fluctuates, good responsiveness can be obtained by controlling the degree of opening of the steam valve 10 as described above.

The load change estimator 150 determines whether the possibility of load change is high or low, for example, by quantifying the possibility of load change as a parameter and comparing the magnitude of the parameter with a preset determination threshold. good too.

In one aspect of the present disclosure, the load change estimator 150 may estimate the possibility of change based on the power demand prediction result. In this case, the load change estimator 150 calculates the load change possibility for each unit period by predicting the power demand per unit period (for example, one hour) in the power system.

Prediction of power demand may be made, for example, based on weather forecasts and past performance of power usage. Specifically, the past record of power consumption is information in which the environmental record and the power consumption are associated with each other. Environmental performance is the past performance of environmental information, including weather information, that affects power demand. For example, in addition to weather, temperature, humidity, etc., information such as wind speed, amount of solar radiation, hours of sunshine, time of year, and season may be included. In other words, the past record of power consumption indicates the record of power consumption under the conditions indicated by the past environmental record. The past record of power usage may include regional information, and may take into consideration the particularities of the region.

Then, using a demand forecast model that calculates power consumption from environmental information, created by learning (machine learning) the relationship between environmental performance and power consumption based on past power consumption results, weather forecasts are used. A predicted value of power demand may be calculated from the extracted information. For example, the demand forecasting model calculates the amount of solar radiation for each piece of environmental performance information, and machine-learns the relationship between at least one piece of information included in the calculated actual amount of solar radiation and the weather forecast, and power consumption. Alternatively, the predicted value of power demand may be calculated from the amount of solar radiation or the like.

The power demand may be obtained by forecasting as an integrated value of the demand of each demand destination connected to the power system, or by predicting the demand of each demand destination connected to the power system individually. may be

In another aspect of the present disclosure, the load change estimator 150 may estimate the possibility of change based on the prediction result of the power generation amount of renewable energy. Any known technique may be employed for predicting the amount of power generated by renewable energy. For example, the prediction of the power generation amount of renewable energy may be the total amount of wind power generation, hydroelectric power generation, solar power generation, etc., whose power generation amount changes depending on environmental conditions, or may be predicted based on a weather forecast.

If the renewable energy is hydroelectric power generation, a predicted value of the hydroelectric power generation amount may be calculated based on past performance as a base load power source.

If the renewable energy is wind power generation, the wind speed may be calculated from the weather forecast, and the amount of power generation may be predicted based on this wind speed and past performance. For example, a wind power generation forecast that calculates wind power generation from wind speed, created by learning (machine learning) the relationship between actual wind speed accumulated as past performance and actual wind power generation at that time A model may be used to calculate the predicted value of wind power generation from the wind speed (predicted value of wind speed) extracted from the weather forecast.

When the renewable energy is photovoltaic power generation, since light energy from the sun is converted into electric energy, the amount of power generation increases as the amount of solar radiation increases. However, when the amount of solar radiation increases, the air temperature and the temperature of the panel that converts the energy described above increase accordingly, so the power generation efficiency decreases. Therefore, the amount of solar radiation and the temperature of the panel may be predicted based on the weather forecast to calculate the power generation amount. More specifically, for example, the hours of sunshine and temperature per unit period are extracted from the weather forecast for a predetermined period. In addition, the solar radiation intensity for each unit period is predicted based on weather information (sunny, cloudy, rainy, etc.) in the weather forecast. Then, by multiplying the solar radiation intensity and the sunshine duration for each unit period, the solar radiation amount for each unit period is predicted. Based on this, the solar power generation is predicted through the prediction of panel temperature.

In another aspect of the present disclosure, selection of the control mode by the control mode selection unit 130 may be performed as manual work by the operator. In this case, the operator monitors the load command value Ld on a display or the like, and selects an appropriate control mode based on changes in the load command value Ld and past performance. Mode selection by the operator is performed by inputting a control mode selection signal corresponding to the content of the operator's selection to the control mode selection unit 130 . As a result, it is possible to select an appropriate control mode in consideration of individual circumstances that are difficult to consider in automatic control.

As described above, each aspect of the present disclosure provides a power plant control device, a power plant, and a power plant control method that can follow the output of the power plant with good responsiveness when a load increase request is made. can.

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

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

(1) A power plant control device according to an aspect of the present disclosure includes:
a steam generator configured to generate steam;
a generator coupled to a turbine configured to be driven using the steam;
a steam valve for controlling the amount of steam supplied to the turbine;
A control device for a power plant comprising
a steam valve control unit configured to control the steam valve so that the output of the generator becomes a load command value for the power plant;
a steam generator control unit configured to control the steam generator such that the steam pressure of the steam generator reaches a target pressure value;
a control mode selection unit configured to be able to select either the normal mode or the load change corresponding mode;
A second target pressure value obtained by adding a bias value to the first target pressure value corresponding to the normal mode is set as the target pressure value when the load change corresponding mode is selected by the control mode selection unit. A target pressure value correction unit configured as
Prepare.

According to the aspect (1) above, the steam pressure of the steam generator is controlled to be high by setting the target pressure value higher in the load change corresponding mode than in the normal mode. As a result, the degree of opening of the steam valve controlled so that the generator output becomes equal to the load command value is narrowed compared to the normal mode, and the control margin of the degree of opening of the steam valve is ensured. As a result, when the load command value fluctuates in the load fluctuation handling mode, load follow-up control with good responsiveness can be achieved by controlling the degree of opening of the steam valve. As described above, in this embodiment, two operation modes, the normal mode and the load change handling mode, can be selected, so that the power plant can be operated in accordance with the required conditions. For example, in the normal mode, the opening of the steam valves is larger than in the load fluctuation response mode, so it is possible to operate with an emphasis on plant efficiency. It is possible to operate with an emphasis on responsiveness to load fluctuations.

(2) In another aspect, in the aspect of (1) above,
The steam valve control unit controls the steam valve so that the degree of opening of the steam valve becomes a first degree of opening corresponding to the maximum degree of opening when the load command value is in a steady state in the normal mode.

According to the aspect (2) above, in the normal mode, when the load command value is in a steady state (when the fluctuation width of the load command value is equal to or less than the reference value, for example, when it is constant), the opening degree of the steam valve By controlling to the maximum opening, good plant efficiency can be obtained.

(3) In another aspect, in the aspect of (2) above,
When the load command value is in a steady state in the load change corresponding mode, the steam valve control unit controls the steam valve so that the opening degree of the steam valve is a second opening degree smaller than the first opening degree. Control.

According to the above aspect (3), when the load command value is in a steady state in the load change corresponding mode (when the fluctuation range of the load command value is equal to or less than the reference value, for example, when it is constant), the steam valve By controlling the degree of opening to be smaller than the maximum degree of opening, when the load command value fluctuates, load follow-up control with good responsiveness becomes possible by controlling the degree of opening of the steam valve.

(4) In another aspect, in any one aspect of (1) to (3) above,
The control mode selection unit is configured to be able to select either the normal mode or the load change corresponding mode based on a control mode selection signal corresponding to an operator's input signal.

According to the above aspect (4), the normal mode and the load change corresponding mode are selectable by the control mode selection signal based on the operator's judgment. As a result, it is possible to switch the operation mode based on the operator's judgment according to various requests and situations for the power plant.

(5) In another aspect, in any one aspect of (1) to (3) above,
further comprising a load variation estimator configured to estimate the possibility of variation of the load command value,
The control mode selection unit is configured to select the load change corresponding mode when the load change estimation unit determines that the load command value is highly likely to change.

According to aspect (5) above, when it is determined that there is a high possibility that the load command value will fluctuate, the load fluctuation handling mode is selected as the power plant control mode. As a result, when the load command value fluctuates, load follow-up control with good responsiveness becomes possible by controlling the degree of opening of the steam valve.

(6) In another aspect, in the aspect of (5) above,
The load change estimator is configured to estimate the possibility of change based on a power demand prediction result.

According to the aspect (6) above, by switching the control mode to the load change handling mode according to the possibility of change in the load command value due to power demand, it is possible to respond with good responsiveness to changes in the load command value. It becomes possible.

(7) In another aspect, in the aspect of (5) above,
The load change estimator is configured to estimate the possibility of change based on a prediction result of the power generation amount of renewable energy.

According to the above aspect (7), by switching the control mode to the load change corresponding mode according to the possibility of fluctuation of the load command value due to the amount of power generated by renewable energy, which is easily affected by weather conditions, the load command value can be changed. It is possible to respond with good responsiveness to fluctuations.

(8) In another aspect, in any one aspect of (1) to (7) above,
The steam generator is a coal-fired boiler that uses coal as fuel.

According to the above aspect (8), even in a power plant using a coal-fired boiler with low responsiveness to a load command value by operation control as a steam generator, due to the process of pulverizing coal with a coal pulverizer, By implementing the load change handling mode, the output of the power plant can be made to follow with good responsiveness even when the load command value fluctuates.

(9) A power plant according to one aspect of the present disclosure includes:
The control device according to any one of (1) to (8) above is provided.

According to the above aspect (9), by selecting the normal mode and the load fluctuation handling mode according to the situation, a power plant capable of achieving both good plant efficiency and good responsiveness to load fluctuations is realized. can.

(10) A power plant control method according to an aspect of the present disclosure includes:
a steam generator configured to generate steam;
a generator coupled to a turbine configured to be driven using the steam;
a steam valve for controlling the amount of steam supplied to the turbine;
A control method for a power plant comprising
a steam valve control step of controlling the steam valve so that the output of the generator becomes a load command value for the power plant;
a steam generator control step of controlling the steam generator such that the steam pressure of the steam generator reaches a target pressure value;
a control mode selection step of selecting either the normal mode or the load change corresponding mode;
with
In the load change corresponding mode, a second target pressure value obtained by adding a bias value to the first target pressure value corresponding to the normal mode is set as the target pressure value.

According to the aspect (10) above, the steam pressure of the steam generator is controlled to be high by setting the target pressure value higher in the load change corresponding mode than in the normal mode. As a result, the degree of opening of the steam valve controlled so that the generator output becomes equal to the load command value is narrowed compared to the normal mode, and the control margin of the degree of opening of the steam valve is ensured. As a result, when the load command value fluctuates in the load fluctuation handling mode, load follow-up control with good responsiveness can be achieved by controlling the degree of opening of the steam valve. As described above, in this embodiment, two operation modes, the normal mode and the load change handling mode, can be selected, so that the power plant can be operated in accordance with the required conditions. For example, in the normal mode, the opening of the steam valves is larger than in the load fluctuation response mode, so it is possible to operate with an emphasis on plant efficiency. It is possible to operate with an emphasis on responsiveness to load fluctuations.

1 Power plant 2 Steam generator 4 Turbine 6 Generator 8 Steam supply line 10 Steam valve 100 Control device 110 Steam valve control unit 120 Steam generator control unit 130 Control mode selection unit 140 Target pressure value correction unit 150 Load fluctuation estimation unit

Claims (8)

a steam generator configured to generate steam;
a generator coupled to a turbine configured to be driven using the steam;
a steam valve for controlling the amount of steam supplied to the turbine;
A control device for a power plant comprising
a steam valve control unit configured to control the steam valve so that the output of the generator becomes a load command value for the power plant;
a steam generator control unit configured to control the steam generator such that the steam pressure of the steam generator reaches a target pressure value;
a control mode selection unit configured to be able to select either the normal mode or the load change corresponding mode;
A second target pressure value obtained by adding a bias value to the first target pressure value corresponding to the normal mode is set as the target pressure value when the load change corresponding mode is selected by the control mode selection unit. A target pressure value correction unit configured as
with
The steam valve control unit
controlling the steam valve so that the degree of opening of the steam valve becomes a first degree of opening corresponding to the maximum degree of opening when the load command value is in a steady state in the normal mode;
controlling the steam valve so that the opening degree of the steam valve becomes a second degree of opening smaller than the first degree of opening when the load command value is in a steady state in the load fluctuation handling mode; Control device. 2. The power plant according to claim 1 , wherein said control mode selection unit is configured to be able to select either said normal mode or said load change handling mode based on a control mode selection signal corresponding to an operator's input signal. controller. further comprising a load variation estimator configured to estimate the possibility of variation of the load command value,
3. The control mode selection unit according to claim 1 , wherein the control mode selection unit is configured to select the load change corresponding mode when the load change estimation unit determines that the load command value is highly likely to change. power plant controller. 4. The power plant control device according to claim 3 , wherein said load fluctuation estimator is configured to estimate said fluctuation possibility based on a power demand prediction result. 4. The power plant control device according to claim 3 , wherein said load fluctuation estimator is configured to estimate said fluctuation possibility based on a prediction result of a power generation amount of renewable energy. The power plant control device according to any one of claims 1 to 5 , wherein the steam generator is a coal-fired boiler using coal as fuel. A power plant comprising the control device according to any one of claims 1 to 6 . a steam generator configured to generate steam;
a generator coupled to a turbine configured to be driven using the steam;
a steam valve for controlling the amount of steam supplied to the turbine;
A control method for a power plant comprising
a steam valve control step of controlling the steam valve so that the output of the generator becomes a load command value for the power plant;
a steam generator control step of controlling the steam generator such that the steam pressure of the steam generator reaches a target pressure value;
a control mode selection step of selecting either the normal mode or the load change corresponding mode;
with
in the normal mode, when the load command value is in a steady state, controlling the steam valve so that the opening degree of the steam valve becomes a first opening degree corresponding to the maximum opening degree;
In the load change corresponding mode, a second target pressure value obtained by adding a bias value to the first target pressure value corresponding to the normal mode is set as the target pressure value, and when the load command value is in a steady state, A control method for a power plant , comprising: controlling the steam valve so that the opening degree of the steam valve becomes a second opening degree smaller than the first opening degree .

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