CN112832873B - Control method and control system of constant voltage unit participating in power grid frequency modulation - Google Patents
Control method and control system of constant voltage unit participating in power grid frequency modulation Download PDFInfo
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- CN112832873B CN112832873B CN202110004037.1A CN202110004037A CN112832873B CN 112832873 B CN112832873 B CN 112832873B CN 202110004037 A CN202110004037 A CN 202110004037A CN 112832873 B CN112832873 B CN 112832873B
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- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F01—MACHINES OR ENGINES IN GENERAL; ENGINE PLANTS IN GENERAL; STEAM ENGINES
- F01D—NON-POSITIVE DISPLACEMENT MACHINES OR ENGINES, e.g. STEAM TURBINES
- F01D17/00—Regulating or controlling by varying flow
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- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F01—MACHINES OR ENGINES IN GENERAL; ENGINE PLANTS IN GENERAL; STEAM ENGINES
- F01D—NON-POSITIVE DISPLACEMENT MACHINES OR ENGINES, e.g. STEAM TURBINES
- F01D17/00—Regulating or controlling by varying flow
- F01D17/10—Final actuators
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- H—ELECTRICITY
- H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
- H02J—CIRCUIT ARRANGEMENTS OR SYSTEMS FOR SUPPLYING OR DISTRIBUTING ELECTRIC POWER; SYSTEMS FOR STORING ELECTRIC ENERGY
- H02J3/00—Circuit arrangements for ac mains or ac distribution networks
- H02J3/24—Arrangements for preventing or reducing oscillations of power in networks
- H02J3/241—The oscillation concerning frequency
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- H—ELECTRICITY
- H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
- H02J—CIRCUIT ARRANGEMENTS OR SYSTEMS FOR SUPPLYING OR DISTRIBUTING ELECTRIC POWER; SYSTEMS FOR STORING ELECTRIC ENERGY
- H02J3/00—Circuit arrangements for ac mains or ac distribution networks
- H02J3/38—Arrangements for parallely feeding a single network by two or more generators, converters or transformers
- H02J3/46—Controlling of the sharing of output between the generators, converters, or transformers
- H02J3/466—Scheduling the operation of the generators, e.g. connecting or disconnecting generators to meet a given demand
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- Control Of Eletrric Generators (AREA)
Abstract
The application discloses a control method and a control system of a constant-pressure unit participating in power grid frequency modulation, relates to the technical field of automatic control of thermal generator sets, and aims to solve the technical problem that the main steam pressure of the constant-pressure unit is influenced when the constant-pressure unit participates in primary frequency modulation of a power grid, and the control method of the constant-pressure unit participating in power grid frequency modulation comprises the following steps: acquiring a first pressure value of a constant pressure unit, wherein the first pressure value is a real-time pressure value of the main steam pressure of the constant pressure unit; judging whether the first pressure value is within the allowable value range of the main steam pressure; under the condition that the first pressure value is determined to be within the allowable range of the main steam pressure, controlling the constant pressure unit to respond to the target load instruction so as to enable the constant pressure unit to participate in the primary frequency modulation process of the power grid; the target load instruction is a load instruction output to the constant voltage unit by the power grid in the primary frequency modulation process. The method and the device are used for coordinately controlling the main steam pressure and primary frequency modulation of the constant pressure unit.
Description
Technical Field
The application relates to the technical field of automatic control of thermal generator sets, in particular to a control method and a control system of a constant voltage unit participating in power grid frequency modulation.
Background
In a thermal power plant, a generator set operating in a constant-voltage operation mode is called a constant-voltage set. The main steam pressure of the constant pressure unit is generally a fixed value set by an operator, and is called a rated value of the main steam pressure. When the constant pressure unit normally operates, the main steam pressure of the constant pressure unit is preferably maintained at a rated value so as to ensure safe and stable operation of the power grid.
In the process that the constant-voltage unit participates in primary frequency modulation of the power grid, the related technology can control the heat storage of the generator unit according to the LDC (Load Demand Computer, load instruction arithmetic unit) load instruction sent by the power grid so as to rapidly increase and decrease the load and respond to the requirement of load change of the primary frequency modulation.
However, the main steam pressure of the constant-pressure unit is influenced when the constant-pressure unit participates in primary frequency modulation of the power grid: the load change of the constant-pressure unit when participating in primary frequency modulation of the power grid causes the main steam pressure of the constant-pressure unit to change greatly, so that the main steam pressure of the constant-pressure unit is difficult to maintain at a rated value, and the safe and stable operation of the power grid is damaged.
Disclosure of Invention
The embodiment of the application aims to provide a control method and a control system of a constant-pressure unit participating in power grid frequency modulation, so as to solve the technical problem that the main steam pressure of the constant-pressure unit is influenced when the constant-pressure unit participates in primary frequency modulation of a power grid in the related technology.
In order to solve the technical problems, the embodiment of the application is realized as follows:
in a first aspect, an embodiment of the present application provides a control method of a constant voltage unit participating in frequency modulation of a power grid, including: acquiring a first pressure value of a constant pressure unit, wherein the first pressure value is a real-time pressure value of the main steam pressure of the constant pressure unit; judging whether the first pressure value is within the allowable value range of the main steam pressure; under the condition that the first pressure value is determined to be within the allowable range of the main steam pressure, controlling the constant pressure unit to respond to the target load instruction so as to enable the constant pressure unit to participate in the primary frequency modulation process of the power grid; the target load instruction is a load instruction output to the constant voltage unit by the power grid in the primary frequency modulation process.
In a second aspect, an embodiment of the present application provides a control system of a constant voltage unit participating in frequency modulation of a power grid, including: the distributed control unit is used for acquiring a first pressure value of the constant pressure unit, wherein the first pressure value is a real-time pressure value of the main steam pressure of the constant pressure unit; judging whether the first pressure value is within the allowable value range of the main steam pressure; under the condition that the first pressure value is determined to be within the allowable range of the main steam pressure, controlling the constant pressure unit to respond to the target load instruction so as to enable the constant pressure unit to participate in the primary frequency modulation process of the power grid; the target load instruction is a load instruction output to the constant voltage unit by the power grid in the primary frequency modulation process.
The embodiment of the application can achieve the following beneficial effects: the method comprises the steps of obtaining a first pressure value of a constant pressure unit, wherein the first pressure value is a real-time pressure value of main steam pressure of the constant pressure unit; judging whether the first pressure value is within the allowable value range of the main steam pressure; under the condition that the first pressure value is determined to be within the allowable range of the main steam pressure, controlling the constant pressure unit to respond to the target load instruction so as to enable the constant pressure unit to participate in the primary frequency modulation process of the power grid; therefore, the main steam pressure of the constant pressure unit is ensured to fluctuate within an allowable value range, and the safe and stable operation of the unit is ensured; the constant pressure unit can participate in the primary frequency modulation process of the power grid on the premise that the main steam pressure of the constant pressure unit fluctuates within the allowable value range; the influence on the main steam pressure of the constant-pressure unit when the constant-pressure unit participates in primary frequency modulation of the power grid is relieved.
Drawings
The accompanying drawings, which are included to provide a further understanding of the application and are incorporated in and constitute a part of this application, illustrate embodiments of the application and together with the description serve to explain the application and do not constitute an undue limitation to the application. In the drawings:
fig. 1 is one of schematic flowcharts of a control method of a constant voltage unit participating in power grid frequency modulation according to an embodiment of the present application;
FIG. 2 is one of schematic flowcharts of a control method of a constant voltage unit participating in grid frequency modulation according to an embodiment of the present application;
FIG. 3 is one of schematic flowcharts of a control method of a constant voltage unit participating in grid frequency modulation according to an embodiment of the present application;
fig. 4 is one of schematic flowcharts of a control method of a constant voltage unit participating in power grid frequency modulation according to an embodiment of the present application;
FIG. 5 is one of schematic flowcharts of a control method of a constant voltage unit participating in grid frequency modulation according to an embodiment of the present application;
FIG. 6 is one of the schematic flowcharts of a control method of a constant voltage unit participating in grid frequency modulation according to an embodiment of the present application;
fig. 7 is one of schematic flowcharts of a control method of a constant voltage unit participating in power grid frequency modulation according to an embodiment of the present application;
fig. 8 is one of schematic block diagrams of a control system of a constant voltage unit participating in power grid frequency modulation according to an embodiment of the present application.
Detailed Description
For the purposes, technical solutions and advantages of the present application, the technical solutions of the present application will be clearly and completely described below with reference to specific embodiments of the present application and corresponding drawings. It will be apparent that the described embodiments are only some, but not all, of the embodiments of the present application. All other embodiments, which can be made by one of ordinary skill in the art without undue burden from the present disclosure, are within the scope of the present disclosure.
The features of the terms "first", "second", and the like in the description and in the claims of this application may be used for descriptive or implicit inclusion of one or more such features. In the description of the present application, unless otherwise indicated, the meaning of "a plurality" is two or more. Furthermore, in the description and claims, "and/or" means at least one of the connected objects, and the character "/", generally means that the associated object is an "or" relationship.
In the description of the present application, it should be noted that, unless explicitly specified and limited otherwise, the terms "mounted," "connected," and "connected" are to be construed broadly, and may be, for example, mechanically or electrically connected; can be directly connected or indirectly connected through an intermediate medium, and can be communication between two elements. The specific meaning of the terms in this application will be understood by those of ordinary skill in the art in a specific context.
In the related art, the load change of the constant-pressure unit when participating in primary frequency modulation of the power grid causes larger change of the main steam pressure of the constant-pressure unit, and the safe and stable operation of the power grid is damaged. In order to coordinate the contradiction between the pressure value of the main steam pressure of the constant-pressure unit and the primary frequency modulation action of the constant-pressure unit in the power grid, the embodiment of the application provides a control method and a control system of the constant-pressure unit in the power grid frequency modulation.
In a first aspect, an embodiment of the present application provides a control method for a constant voltage unit participating in power grid frequency modulation. The control method of the constant voltage unit participating in power grid frequency modulation provided by the embodiment of the application is specifically described below with reference to fig. 1 to 7.
As shown in fig. 1, fig. 1 is a schematic flowchart of a control method of a constant voltage unit participating in power grid frequency modulation according to an embodiment of the present application, where in the embodiment of the present application, the method may include:
In step 110, the constant pressure unit may be a generator set operating in a constant pressure operation, and the generator set may include a boiler, a turbine, and a generator. Taking a thermal generator set as an example, the thermal generator set takes coal, fuel oil, fuel gas and the like as fuels, heats water in a boiler, heats the water into steam in the boiler, and the steam enters a steam turbine through a steam pipeline to push blades of the steam turbine to rotate so as to drive a generator to generate electricity.
The main steam of the boiler inlet enters the steam turbine through a pipeline, and the main steam pressure of the constant pressure unit can be the main steam pressure of the boiler inlet. In the constant pressure unit participating in the frequency modulation of the power grid, the first pressure value may be a real-time pressure value of the main steam pressure of the constant pressure unit before participating in the primary frequency modulation of the power grid.
It should be noted that, the embodiment of the present application is not limited to the specific embodiment of acquiring the first pressure value, for example, the first pressure value may be acquired using a pressure sensor, and so on.
In step 120, the constant pressure unit may be operated normally within the allowable range of the main steam pressure. The allowable range of the main vapor pressure may be (P-a, p+a). Specifically, a first threshold value and a second threshold value of an allowable value range of the main vapor pressure are set, wherein the first threshold value is the difference P-a between the rated value and the threshold value of the main vapor pressure, and the second threshold value is the sum P+a of the rated value and the threshold value of the main vapor pressure.
The rated value P is a rated value of main steam pressure, the rated value is a fixed value set by an operator, and the main steam pressure of the constant pressure unit in the related art is preferably maintained at the rated value so as to ensure safe and stable operation of a power grid.
Wherein a is a threshold value of the main steam pressure set by an operator.
In the embodiment of the application, a part of pressure value can be sacrificed, so that the constant pressure unit is allowed to normally operate within the allowable range that the deviation of the main steam pressure from the rated value P does not exceed the threshold value a.
In step 130, under the condition that the first pressure value is determined to be within the allowable value range of the main steam pressure, the constant-pressure unit in the power grid can participate in the primary frequency modulation process of the power grid, and the DCS (Distributed Control System ) system can control the constant-pressure unit to act in response to the target load command so as to enable the constant-pressure unit to participate in the primary frequency modulation process of the power grid;
the target load instruction is a load instruction output to the constant voltage unit by the power grid in the primary frequency modulation process. Specifically, the target load instruction may be a load instruction after primary frequency modulation of the power grid, the power grid outputs the target load instruction to the DCS system, and an operation station in the DCS system outputs the target load instruction to the constant voltage unit to control the constant voltage unit to increase or decrease the load based on a load value indicated by the target load instruction.
It can be appreciated that in the case that the first pressure value is determined to be outside the allowable range of the main steam pressure, for example, the first pressure value is determined to be smaller than the first threshold value, or the first pressure value is determined to be larger than the second threshold value, in this case, the constant pressure unit can be controlled not to act in response to the target load instruction, so as to avoid that the constant pressure unit participates in the primary frequency modulation process of the power grid to cause a large change to the main steam pressure of the constant pressure unit, and the safe and stable operation of the power grid is threatened.
On the other hand, it may be understood that, in the case where it is determined that the first pressure value is equal to the first threshold value, the embodiment of the present application may further determine whether the sign of the load value indicated by the target load command is a positive value, or determine whether the sign of the load value indicated by the target load command is a negative value, where if the load value of the target load command is a positive value, the constant pressure unit operates in response to the load value, and may cause the first pressure value to decrease while increasing the load. That is, under the condition that the first pressure value is equal to the first threshold value, if the load value indicated by the target load instruction is a positive value, the constant-pressure unit is controlled not to respond to the target load instruction, so that the situation that the constant-pressure unit participates in the primary frequency modulation process of the power grid to cause great change to the main steam pressure of the constant-pressure unit is avoided, and the safe and stable operation of the power grid is threatened. And under the condition that the first pressure value is equal to the first threshold value, if the load value indicated by the target load instruction is a negative value, controlling the constant-pressure unit to respond to the target load instruction so as to enable the constant-pressure unit to participate in the primary frequency modulation process of the power grid.
Similarly, in the case where it is determined that the first pressure value is equal to the second threshold value, the embodiment of the present application may further determine whether the sign of the load value indicated by the target load instruction is a positive value, or determine whether the sign of the load value indicated by the target load instruction is a negative value, where if the load value of the target load instruction is a positive value, the constant pressure unit responds to the load value action, and may cause the first pressure value to decrease while increasing the load. That is, if the first pressure value is determined to be equal to the second threshold value, if the load value indicated by the target load command is a positive value, the constant voltage unit is controlled to act in response to the target load command, so that the constant voltage unit participates in the primary frequency modulation process of the power grid. Under the condition that the first pressure value is equal to the second threshold value, if the load value indicated by the target load instruction is a negative value, the constant-pressure unit is controlled not to respond to the target load instruction to act, so that the situation that the constant-pressure unit participates in the primary frequency modulation process of the power grid to cause large change to the main steam pressure of the constant-pressure unit is avoided, and the safe and stable operation of the power grid is threatened.
According to the control method of the constant-pressure unit participating in power grid frequency modulation, the first pressure value of the constant-pressure unit is obtained, and the first pressure value is a real-time pressure value of main steam pressure of the constant-pressure unit; judging whether the first pressure value is within the allowable value range of the main steam pressure; under the condition that the first pressure value is determined to be within the allowable range of the main steam pressure, controlling the constant pressure unit to respond to the target load instruction so as to enable the constant pressure unit to participate in the primary frequency modulation process of the power grid; therefore, the main steam pressure of the constant pressure unit is ensured to fluctuate within an allowable value range, and the safe and stable operation of the unit is ensured; the constant pressure unit can participate in the primary frequency modulation process of the power grid on the premise that the main steam pressure of the constant pressure unit fluctuates within the allowable value range; the influence on the main steam pressure of the constant-pressure unit when the constant-pressure unit participates in primary frequency modulation of the power grid is relieved.
As shown in fig. 2, fig. 2 is a schematic flowchart of a control method of a constant voltage unit participating in power grid frequency modulation according to an embodiment of the present application, and in the embodiment of the present application, step 120: judging whether the first pressure value is within the allowable value range of the main steam pressure or not specifically comprises the following steps:
step 121: a first deviation value is determined based on the first pressure value, wherein the first deviation value is a difference between the first pressure value and a nominal value of the main vapor pressure.
In step 121, in the embodiment of the present application, the constant pressure unit may normally operate within an allowable range in which the deviation amount (i.e., the first deviation value) of the main steam pressure from the rated value does not exceed the threshold value.
In a specific embodiment, the operator can manually set a setpoint value for the main gas pressure in the operator station of the DCS system, for example, 23.5Mpa as the setpoint value for the main gas pressure, and the DCS system further has a special calculation block, which can determine the first deviation value by calculating the difference between the first pressure value and the setpoint value for the main gas pressure.
Step 122: and judging whether the absolute value of the first deviation value is smaller than a threshold value, wherein the threshold value is a positive value.
In a specific embodiment, the threshold value may be preset by an operator according to an actual operation condition of the constant pressure unit, for example, the operator may manually set a threshold value of the main steam pressure in an operation station of the DCS system, for example, manually input 0.5Mpa as the threshold value of the main steam pressure. Thus, the allowable range of the main steam pressure can be (23.5-0.5, 23.5+0.5) Mpa, namely (22, 24) Mpa, and the main steam pressure of the constant pressure unit needs to fluctuate within the range of 22Mpa to 24Mpa in order to ensure the safe and stable operation of the unit.
Step 123: and if the absolute value of the first deviation value is smaller than the threshold value, the first pressure value is within the allowable value range of the main steam pressure.
Accordingly, in the embodiment of the present application, as shown in fig. 2, step 130: and under the condition that the first pressure value is determined to be within the allowable range of the main gas pressure, controlling the constant pressure unit to respond to the target load command, wherein the method specifically comprises the following steps of:
step 131: and under the condition that the absolute value of the first deviation value is smaller than the threshold value, controlling the constant voltage unit to act in response to the target load instruction so as to enable the constant voltage unit to participate in the primary frequency modulation process of the power grid.
According to the control method of the constant-pressure unit participating in power grid frequency modulation, the first pressure value of the constant-pressure unit is obtained, and the first pressure value is a real-time pressure value of main steam pressure of the constant-pressure unit; determining a first deviation value based on the first pressure value, wherein the first deviation value is a difference between the first pressure value and a nominal value of the main gas pressure; judging whether the absolute value of the first deviation value is smaller than a threshold value, wherein the threshold value is a positive value; if the absolute value of the first deviation value is smaller than the threshold value, the first pressure value is within the allowable value range of the main steam pressure; and under the condition that the absolute value of the first deviation value is smaller than the threshold value, controlling the constant voltage unit to act in response to the target load instruction so as to enable the constant voltage unit to participate in the primary frequency modulation process of the power grid. Therefore, the main steam pressure of the constant pressure unit is ensured to run safely and stably under the condition that the deviation amount of the main steam pressure from the rated value does not exceed the threshold value; the primary steam pressure of the constant-pressure unit can be enabled to participate in the primary frequency modulation process of the power grid on the premise that the deviation amount of the constant-pressure unit from the rated value is not more than a threshold value; the influence on the main steam pressure of the constant-pressure unit when the constant-pressure unit participates in primary frequency modulation of the power grid is relieved.
As shown in fig. 3, fig. 3 is a schematic flowchart of a control method of a constant voltage unit participating in power grid frequency modulation according to an embodiment of the present application, in this embodiment of the present application, after step 110, before step 120, the method further includes:
step 141: acquiring a load value indicated by the target load instruction;
in step 141, the target load command may be a grid primary frequency modulated load command, where the target load command indicates a load value that includes a conventional user load command plus a primary frequency modulated load command, that is, the target load command indicates a load value that includes both a load value generated based on a fluctuation in the user's power load and a load value indicated by a primary frequency modulated command action. For example, after the grid undergoing primary frequency modulation outputs the target load instruction to the DCS system, if the load value indicated by the target load instruction is 15MW, that is, the load value of the constant-pressure unit is indicated to be adjusted by 15MW upwards, the opening of the steam turbine valve can be controlled to be increased based on the target load instruction, so that the load of the constant-pressure unit is increased by 15MW; if the load value indicated by the target load instruction is-15 MW, namely the load value of the constant-pressure unit is indicated to be adjusted downwards by 15MW, the opening of the steam turbine valve can be controlled to be reduced based on the target load instruction, so that the load of the constant-pressure unit is reduced by 15MW.
In the embodiment of the application, the load value indicated by the target load instruction can be obtained through the target load instruction received by the DCS system.
In step 141, when the opening degree of the turbine governor is controlled to be increased based on the target load command, the main steam pressure is caused to be reduced while increasing the load; when the opening degree of the turbine governor is controlled to be reduced based on the target load command, the main steam pressure is caused to be increased while the load is reduced.
Step 142: determining an allowable value range of the target load command according to the first pressure value;
in step 142, an allowable range of the target load command may be predetermined based on the first pressure value. Specifically, the allowable value range of the target load command estimated in advance based on the first pressure value may be: if the load value indicated by the target load command is the third threshold value, the first pressure value that causes the main steam pressure by controlling the change in the opening degree of the turbine governor based on the target load command is the first threshold value. In this way, when the first pressure value is the first threshold value, the load value indicated by the acquisition target load instruction may be determined as the third threshold value. If the load value indicated by the target load command is the fourth threshold value, the first pressure value of the main steam pressure caused by the change in the opening degree of the turbine governor controlled based on the target load command is the second threshold value. In this way, when the first pressure value is the second threshold value, the load value indicated by the acquisition target load instruction may be determined as the fourth threshold value.
Thereby, a load value between the third threshold value and the fourth threshold value is determined as the allowable value range of the target load command.
Correspondingly, the step 120 specifically includes: step 124: and judging whether the load value is within the allowable value range of the target load instruction.
If it is determined in step 124 that the load value indicated by the target load command is between the third threshold value and the fourth threshold value, it may be determined that the first pressure value caused by the load value is within the allowable range of the main vapor pressure.
Correspondingly, step 130 specifically includes step 132: and controlling the constant voltage unit to act in response to the target load command under the condition that the load value is determined to be within the allowable value range of the target load command.
According to the control method of the constant-pressure unit participating in power grid frequency modulation, the first pressure value of the constant-pressure unit is obtained, and the first pressure value is a real-time pressure value of main steam pressure of the constant-pressure unit; and acquiring a load value indicated by the target load instruction, determining an allowable value range of the target load instruction according to the first pressure value, judging whether the load value is within the allowable value range of the target load instruction, and controlling the constant voltage unit to respond to the target load instruction under the condition that the load value is determined to be within the allowable value range of the target load instruction. Thus, under the condition that the load value indicated by the target load instruction is within the allowable value range of the target load instruction, the constant-pressure unit is controlled to act in response to the target load instruction, and the target load instruction within the allowable value range of the target load instruction is limited to act in response to the target load instruction, so that the main steam pressure of the constant-pressure unit is ensured to fluctuate within the allowable value range, and the safe and stable operation of the unit is ensured; the constant voltage unit can participate in the primary frequency modulation process of the power grid within the allowable value range of the target load instruction; the influence on the main steam pressure of the constant-pressure unit when the constant-pressure unit participates in primary frequency modulation of the power grid is relieved.
As shown in fig. 4, fig. 4 is a schematic flowchart of a control method of a constant voltage unit participating in power grid frequency modulation according to an embodiment of the present application, and in a specific embodiment, step 130 specifically includes steps 133 to 135.
Step 133: it is determined whether the load value indicated by the target load command is a positive value.
Step 134: and when the load value indicated by the target load instruction is a positive value, controlling the opening degree of the turbine valve to be increased so as to increase the load of the constant pressure unit.
Step 135: and when the load value indicated by the target load instruction is a negative value, controlling the opening degree of the steam turbine valve to be reduced so as to reduce the load of the constant pressure unit.
The steam turbine valve is a valve of a steam turbine in a constant pressure unit.
For example, in step 133, it may be determined whether the load value indicated by the target load instruction is a positive value or whether the load value indicated by the target load instruction is a negative value. It can be understood that after the grid undergoing primary frequency modulation outputs the target load instruction to the DCS system, if the load value indicated by the target load instruction is a positive value, for example, 15MW, that is, the load value indicating the constant-pressure unit is adjusted upwards by 15MW, the opening of the turbine valve can be controlled to be increased based on the target load instruction, so that the load of the constant-pressure unit is increased by 15MW; if the load value indicated by the target load instruction is a negative value, for example, -15MW, namely, the load value of the constant-pressure unit is indicated to be adjusted downwards by 15MW, the opening degree of the turbine valve can be controlled to be reduced based on the target load instruction, so that the load of the constant-pressure unit is reduced by 15MW.
According to the control method of the constant-voltage unit participating in power grid frequency modulation, the opening change of the steam turbine regulating gate is controlled through the load value indicated by the target load instruction, so that the load is controlled to be increased or decreased, and the constant-voltage unit is enabled to rapidly respond to the load change in the primary frequency modulation process of the power grid.
In addition, after the constant pressure unit participates in primary frequency modulation of the power grid, if the pressure value of the main steam pressure caused by the primary frequency modulation deviates and the deviation exceeds the allowable value range of the main steam pressure of the constant pressure unit, in this case, the control method of the constant pressure unit participating in the frequency modulation of the power grid provided by the embodiment of the application can also reversely pull back the deviation pressure value so as to compensate the pressure deviation which is generated after the primary frequency modulation and exceeds the allowable value range of the main steam pressure of the constant pressure unit. In a specific embodiment, as shown in fig. 5, after step 130, the control method further includes:
step 151: acquiring a second pressure value, wherein the second pressure value is a real-time pressure value of the main steam pressure of the constant pressure unit after primary frequency modulation;
step 152: determining a second offset value for the set of constant pressures based on the second pressure value; wherein the second deviation value is a difference between the second pressure value and a nominal value of the main steam pressure;
Step 153: judging whether the absolute value of the second deviation value is larger than a threshold value, wherein the threshold value is a positive value;
step 154: and under the condition that the absolute value of the second deviation value is larger than a threshold value, controlling the steam turbine valve regulating action of the constant pressure unit based on the second deviation value so as to maintain the second pressure value within the allowable range of the main steam pressure.
For example, a dedicated computing module in the DCS system may obtain a second pressure value, determine a second deviation value of the constant pressure unit based on the second pressure value, and determine that the absolute value of the second deviation value is greater than the threshold value. At this time, the DCS system can output a valve control command to a controller in a main control closed loop system of the steam turbine to control the valve operation of the steam turbine and adjust the opening of the valve of the steam turbine.
According to the control method of the constant-pressure unit participating in power grid frequency modulation, the second pressure value is obtained, and the second pressure value is a real-time pressure value of the main steam pressure of the constant-pressure unit after primary frequency modulation; determining a second offset value for the set of constant pressures based on the second pressure value; wherein the second deviation value is a difference between the second pressure value and a nominal value of the main steam pressure; judging whether the absolute value of the second deviation value is larger than a threshold value, wherein the threshold value is a positive value; and under the condition that the absolute value of the second deviation value is larger than a threshold value, controlling the steam turbine valve regulating action of the constant pressure unit based on the second deviation value so as to maintain the second pressure value within the allowable range of the main steam pressure. Therefore, under the condition that the second pressure value caused by primary frequency modulation exceeds the allowable value range of the main steam pressure, the valve regulating action of the steam turbine of the constant pressure unit can be controlled, and the pressure deviation exceeding the allowable value range of the main steam pressure of the constant pressure unit, which is generated after primary frequency modulation, is reversely pulled back, so that the fluctuation of the main steam pressure of the constant pressure unit within the allowable value range is ensured, and the safe and stable operation of the unit is ensured.
In a specific embodiment, as shown in fig. 6, the controlling the valve-adjusting action of the turbine of the constant pressure unit based on the second deviation value specifically includes:
step 155: determining a difference between the absolute value of the second deviation value and the threshold value;
step 156: and controlling the steam turbine valve regulating action of the constant pressure unit based on the difference value between the absolute value of the second deviation value and the threshold value.
For example, in step 155, if the rated value of the main steam pressure set by the operator is 23.5Mpa, the threshold value is 0.5Mpa, the real-time pressure value of the main steam pressure of the constant pressure unit after primary frequency modulation is 25Mpa, the second deviation value is 25-23.5=1.5 Mpa, and the difference between the absolute value of 1.5Mpa and the threshold value of 0.5Mpa is 1Mpa. In step 156, based on 1Mpa, the opening of the turbine governor of the constant pressure unit is controlled to be increased so as to reduce the main steam pressure of the constant pressure unit by at least 1Mpa, and the second pressure value is maintained within the allowable range of the main steam pressure.
According to the control method of the constant-pressure unit participating in power grid frequency modulation, which is provided by the embodiment of the application, the turbine regulating valve of the constant-pressure unit is controlled to conduct the regulating action based on the difference value between the absolute value of the second deviation value and the threshold value so as to maintain the second pressure value within the allowable value range of the main steam pressure, so that the fluctuation of the main steam pressure of the constant-pressure unit within the allowable value range is ensured, and the safe and stable operation of the unit is ensured.
As shown in fig. 7, in a specific embodiment, the control method further includes: step 157: and judging whether the second deviation value is a positive value or not.
Accordingly, step 156 specifically includes:
step 158: controlling the opening degree of a turbine valve to be increased based on the difference value between the absolute value of the second deviation value and the threshold value under the condition that the second deviation value is a positive value so as to reduce the second pressure value until the second pressure value is maintained within the allowable range of the main steam pressure;
step 159: and under the condition that the second deviation value is a negative value, controlling the opening degree of a turbine valve to be reduced based on the difference value between the absolute value of the second deviation value and the threshold value so as to increase the second pressure value until the second pressure value is maintained within the allowable range of the main steam pressure.
According to the control method of the constant pressure unit participating in power grid frequency modulation, based on the difference value between the absolute value of the second deviation value and the threshold value, the turbine regulating valve of the constant pressure unit is controlled to conduct accurate movement so as to maintain the second pressure value within the allowable range of the main steam pressure, and particularly under the condition that the second deviation value is positive, based on the difference value between the absolute value of the second deviation value and the threshold value, the opening degree of the turbine regulating valve is controlled to increase so as to reduce the second pressure value until the second pressure value is maintained within the allowable range of the main steam pressure. And under the condition that the second deviation value is a negative value, controlling the opening degree of a steam turbine valve to be reduced based on the difference value between the absolute value of the second deviation value and the threshold value so as to raise the second pressure value until the second pressure value is maintained within the allowable range of the main steam pressure, ensuring that the main steam pressure of the constant pressure unit fluctuates within the allowable range, and ensuring the safe and stable operation of the unit.
In a second aspect, a control system of a constant voltage unit participating in power grid frequency modulation is provided. The control system of the constant voltage unit participating in power grid frequency modulation provided by the embodiment of the application is specifically described below with reference to fig. 8.
As shown in fig. 8, fig. 8 is a schematic structural block diagram of a control system of a constant voltage unit participating in power grid frequency modulation according to an embodiment of the present application, where the constant voltage unit may include a boiler, a steam turbine, and a generator connected in sequence; the distributed control unit is connected with the boiler, the steam turbine and the generator respectively; the distributed control unit is connected with a power grid. The constant voltage unit can be a generator unit participating in primary frequency modulation in a power grid.
In this embodiment of the present application, the decentralized control unit may be an integrated functional module having a control function, a processing function, a data acquisition function, and an input/output function in an operation station of the DCS system. The decentralized control unit may be configured to: acquiring a first pressure value of a constant pressure unit, wherein the first pressure value is a real-time pressure value of the main steam pressure of the constant pressure unit; judging whether the first pressure value is within the allowable value range of the main steam pressure; under the condition that the first pressure value is determined to be within the allowable range of the main steam pressure, controlling the constant pressure unit to respond to the target load instruction so as to enable the constant pressure unit to participate in the primary frequency modulation process of the power grid; the target load instruction is a load instruction output to the constant voltage unit by the power grid in the primary frequency modulation process.
According to the control system of the constant-pressure unit participating in power grid frequency modulation, which is provided by the embodiment of the application, a first pressure value of the constant-pressure unit is obtained through the distributed control unit, wherein the first pressure value is a real-time pressure value of main steam pressure of the constant-pressure unit; judging whether the first pressure value is within the allowable value range of the main steam pressure; under the condition that the first pressure value is determined to be within the allowable range of the main steam pressure, controlling the constant pressure unit to respond to the target load instruction so as to enable the constant pressure unit to participate in the primary frequency modulation process of the power grid; therefore, the main steam pressure of the constant pressure unit is ensured to fluctuate within an allowable value range, and the safe and stable operation of the unit is ensured; the constant pressure unit can participate in the primary frequency modulation process of the power grid on the premise that the main steam pressure of the constant pressure unit fluctuates within the allowable value range; the influence on the main steam pressure of the constant-pressure unit when the constant-pressure unit participates in primary frequency modulation of the power grid is relieved.
It will be appreciated by those skilled in the art that embodiments of the present application may be provided as a method, system, or computer program product. Accordingly, the present application may take the form of an entirely hardware embodiment, an entirely software embodiment, or an embodiment combining software and hardware aspects. Furthermore, the present application may take the form of a computer program product embodied on one or more computer-usable storage media (including, but not limited to, disk storage, CD-ROM, optical storage, and the like) having computer-usable program code embodied therein.
The present application is described with reference to flowchart illustrations and/or block diagrams of methods, apparatus (systems) and computer program products according to embodiments of the application. It will be understood that each flow and/or block of the flowchart illustrations and/or block diagrams, and combinations of flows and/or blocks in the flowchart illustrations and/or block diagrams, can be implemented by computer program instructions. These computer program instructions may be provided to a processor of a general purpose computer, special purpose computer, embedded processor, or other programmable data processing apparatus to produce a machine, such that the instructions, which execute via the processor of the computer or other programmable data processing apparatus, create means for implementing the functions specified in the flowchart flow or flows and/or block diagram block or blocks.
These computer program instructions may also be stored in a computer-readable memory that can direct a computer or other programmable data processing apparatus to function in a particular manner, such that the instructions stored in the computer-readable memory produce an article of manufacture including instruction means which implement the function specified in the flowchart flow or flows and/or block diagram block or blocks.
These computer program instructions may also be loaded onto a computer or other programmable data processing apparatus to cause a series of operational steps to be performed on the computer or other programmable apparatus to produce a computer implemented process such that the instructions which execute on the computer or other programmable apparatus provide steps for implementing the functions specified in the flowchart flow or flows and/or block diagram block or blocks.
In one typical configuration, a computing device includes one or more processors (CPUs), input/output interfaces, network interfaces, and memory.
The memory may include volatile memory in a computer-readable medium, random Access Memory (RAM) and/or nonvolatile memory, such as Read Only Memory (ROM) or flash memory (flash RAM). Memory is an example of computer-readable media.
Computer readable media, including both non-transitory and non-transitory, removable and non-removable media, may implement information storage by any method or technology. The information may be computer readable instructions, data structures, modules of a program, or other data. Examples of storage media for a computer include, but are not limited to, phase change memory (PRAM), static Random Access Memory (SRAM), dynamic Random Access Memory (DRAM), other types of Random Access Memory (RAM), read Only Memory (ROM), electrically Erasable Programmable Read Only Memory (EEPROM), flash memory or other memory technology, compact disc read only memory (CD-ROM), digital Versatile Discs (DVD) or other optical storage, magnetic cassettes, magnetic tape magnetic disk storage or other magnetic storage devices, or any other non-transmission medium, which can be used to store information that can be accessed by a computing device. Computer-readable media, as defined herein, does not include transitory computer-readable media (transmission media), such as modulated data signals and carrier waves.
It should also be noted that the terms "comprises," "comprising," or any other variation thereof, are intended to cover a non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements does not include only those elements but may include other elements not expressly listed or inherent to such process, method, article, or apparatus. Without further limitation, an element defined by the phrase "comprising one … …" does not exclude the presence of other like elements in a process, method, article or apparatus that comprises the element.
It will be appreciated by those skilled in the art that embodiments of the present application may be provided as a method, system, or computer program product. Accordingly, the present application may take the form of an entirely hardware embodiment, an entirely software embodiment or an embodiment combining software and hardware aspects. Furthermore, the present application may take the form of a computer program product embodied on one or more computer-usable storage media (including, but not limited to, disk storage, CD-ROM, optical storage, and the like) having computer-usable program code embodied therein.
The foregoing is merely exemplary of the present application and is not intended to limit the present application. Various modifications and changes may be made to the present application by those skilled in the art. Any modifications, equivalent substitutions, improvements, etc. which are within the spirit and principles of the present application are intended to be included within the scope of the claims of the present application.
Claims (8)
1. The control method of the constant voltage unit participating in the frequency modulation of the power grid is characterized by comprising the following steps of:
acquiring a first pressure value of a constant pressure unit, wherein the first pressure value is a real-time pressure value of the main steam pressure of the constant pressure unit;
judging whether the first pressure value is within the allowable value range of the main steam pressure;
under the condition that the first pressure value is determined to be within the allowable range of the main steam pressure, controlling the constant pressure unit to respond to the target load instruction so as to enable the constant pressure unit to participate in the primary frequency modulation process of the power grid;
the target load instruction is a load instruction which is output to the constant voltage unit by the power grid in the primary frequency modulation process;
after controlling the set of constant pressure units to act in response to the target load command, the method further comprises:
acquiring a second pressure value, wherein the second pressure value is a real-time pressure value of the main steam pressure of the constant pressure unit after primary frequency modulation;
determining a second offset value for the set of constant pressures based on the second pressure value; wherein the second deviation value is a difference between the second pressure value and a nominal value of the main steam pressure;
judging whether the absolute value of the second deviation value is larger than a threshold value, wherein the threshold value is a positive value;
Controlling a steam turbine valve regulating action of the constant pressure unit based on the second deviation value under the condition that the absolute value of the second deviation value is larger than a threshold value so as to maintain the second pressure value within an allowable range of main steam pressure;
and based on the second deviation value, controlling the valve regulating action of the steam turbine of the constant pressure unit comprises the following steps:
determining a difference between the absolute value of the second deviation value and the threshold value;
and controlling the steam turbine valve regulating action of the constant pressure unit based on the difference value between the absolute value of the second deviation value and the threshold value.
2. The control method according to claim 1, characterized in that said determining whether the first pressure value is within an allowable range of the main vapor pressure specifically includes:
determining a first deviation value based on the first pressure value, wherein the first deviation value is a difference between the first pressure value and a nominal value of the main gas pressure;
judging whether the absolute value of the first deviation value is smaller than a threshold value, wherein the threshold value is a positive value;
and if the absolute value of the first deviation value is smaller than the threshold value, the first pressure value is within the allowable value range of the main steam pressure.
3. The control method according to claim 2, wherein the controlling the constant pressure unit in response to the target load command in the case where it is determined that the first pressure value is within the allowable range of the main gas pressure includes:
and under the condition that the absolute value of the first deviation value is smaller than the threshold value, controlling the constant voltage unit to act in response to the target load instruction so as to enable the constant voltage unit to participate in the primary frequency modulation process of the power grid.
4. The control method according to claim 1, characterized in that the method further comprises:
acquiring a load value indicated by the target load instruction;
determining an allowable value range of the target load command according to the first pressure value;
correspondingly, the judging whether the first pressure value is within the allowable range of the main steam pressure specifically includes:
and judging whether the load value is within the allowable value range of the target load instruction.
5. The control method according to claim 4, wherein the controlling the constant pressure unit in response to the target load command in the case where it is determined that the first pressure value is within the allowable range of the main gas pressure includes:
and controlling the constant voltage unit to act in response to the target load command under the condition that the load value is determined to be within the allowable value range of the target load command.
6. The control method according to claim 1, wherein the control constant pressure unit acts in response to a target load command, specifically comprising:
judging whether the load value indicated by the target load instruction is a positive value or not;
when the load value indicated by the target load instruction is a positive value, controlling the opening of the turbine valve to be increased so as to increase the load of the constant pressure unit;
when the load value indicated by the target load instruction is a negative value, controlling the opening degree of a turbine valve to be reduced so as to reduce the load of a constant pressure unit;
the steam turbine valve is a valve of a steam turbine in a constant pressure unit.
7. The control method according to claim 1, characterized in that the method further comprises:
judging whether the second deviation value is a positive value or not;
correspondingly, the controlling the valve adjusting action of the steam turbine of the constant pressure unit based on the difference value between the absolute value of the second deviation value and the threshold value specifically comprises the following steps:
controlling the opening degree of a turbine valve to be increased based on the difference value between the absolute value of the second deviation value and the threshold value under the condition that the second deviation value is a positive value so as to reduce the second pressure value until the second pressure value is maintained within the allowable range of the main steam pressure;
And under the condition that the second deviation value is a negative value, controlling the opening degree of a turbine valve to be reduced based on the difference value between the absolute value of the second deviation value and the threshold value so as to increase the second pressure value until the second pressure value is maintained within the allowable range of the main steam pressure.
8. A control system of a constant voltage unit participating in power grid frequency modulation, comprising: the distributed control unit is used for acquiring a first pressure value of the constant pressure unit, wherein the first pressure value is a real-time pressure value of the main steam pressure of the constant pressure unit; judging whether the first pressure value is within the allowable value range of the main steam pressure; under the condition that the first pressure value is determined to be within the allowable range of the main steam pressure, controlling the constant pressure unit to respond to the target load instruction so as to enable the constant pressure unit to participate in the primary frequency modulation process of the power grid; the target load instruction is a load instruction which is output to the constant voltage unit by the power grid in the primary frequency modulation process;
the distributed control unit is also used for acquiring a second pressure value after the constant pressure unit is controlled to act in response to the target load instruction, wherein the second pressure value is a real-time pressure value of the main steam pressure of the constant pressure unit after primary frequency modulation;
Determining a second offset value for the set of constant pressures based on the second pressure value; wherein the second deviation value is a difference between the second pressure value and a nominal value of the main steam pressure;
judging whether the absolute value of the second deviation value is larger than a threshold value, wherein the threshold value is a positive value;
controlling a steam turbine valve regulating action of the constant pressure unit based on the second deviation value under the condition that the absolute value of the second deviation value is larger than a threshold value so as to maintain the second pressure value within an allowable range of main steam pressure;
and based on the second deviation value, controlling the valve regulating action of the steam turbine of the constant pressure unit comprises the following steps:
determining a difference between the absolute value of the second deviation value and the threshold value;
and controlling the steam turbine valve regulating action of the constant pressure unit based on the difference value between the absolute value of the second deviation value and the threshold value.
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