Thermal system for deep peak shaving and control method thereof

Abstract

The application discloses a thermal system for deep peak regulation and a control method thereof, and can improve the depth and flexibility of thermal power unit peak regulation. Specifically, the system comprises two coal-fired boilers and three steam turbine units. By determining the total power load indicated by the current power peak regulation demand, the system is switched to different operation modes based on the total power load and preset conditions. In different operation modes, the system can be in the state of one boiler and two machines, or one boiler and one machine. By dynamically switching the pipeline communication mode of the coal-fired boiler and the steam turbine unit in the one boiler and two machine operation system, the system can flexibly adapt to a wide range of power peak regulation demands. By optimizing the operation mode and load matching, the boiler is ensured to always operate in a relatively efficient and stable load range, thereby improving the economy, reliability and peak regulation depth of the whole system.

Description

Technical Field

[0001] This invention relates to the field of thermal power generation technology, and in particular to a thermal system for deep peak shaving and its control method. Background Technology

[0002] Traditionally, thermal power plants, which handle base load and conventional peak shaving, are undergoing a fundamental transformation, needing to become flexible power sources that ensure stable grid operation. To effectively absorb renewable energy and avoid wind and solar curtailment during off-peak periods, thermal power units must exceed their traditional operating limits and engage in deep peak shaving, meaning they must maintain operation at loads far below their rated capacity. This aims to free up sufficient grid connection space for renewable energy generation and enable rapid response to fill power gaps when renewable energy output drops sharply.

[0003] However, deep peak shaving of thermal power units faces a series of key technical bottlenecks, including difficulties in maintaining stable combustion under low boiler loads, significant decreases in unit efficiency, and increased equipment wear. Therefore, researching and improving the deep peak shaving capability of thermal power units has become one of the core technical requirements for building a new power system and supporting the clean transformation of the energy structure. Summary of the Invention

[0004] This invention aims to at least solve one of the technical problems existing in the prior art. Therefore, one objective of this invention is to propose a thermal system control method for deep peak shaving. By dynamically switching the pipeline connection mode between the coal-fired boiler and the steam turbine unit in a single-boiler, two-turbine operating system, it can flexibly adapt to a wide range of power peak shaving demands. By optimizing the operating mode and load matching, it ensures that the boiler always operates within a relatively efficient and stable load range, thereby improving the economy, reliability, and peak shaving depth of the entire system.

[0005] The present invention also proposes a thermal system capable of operating the above-described thermal system control method for deep peak shaving.

[0006] According to a first aspect of the present invention, a control method for a thermal system for deep peak shaving, the thermal system includes two coal-fired boilers and three turbine units. The two coal-fired boilers are a first coal-fired boiler and a second coal-fired boiler, and the three turbine units are a first turbine unit, a second turbine unit, and a third turbine unit. The first coal-fired boiler is connected to the first turbine unit and the third turbine unit via pipelines, and the second coal-fired boiler is connected to the second turbine unit and the third turbine unit via pipelines. The pipelines are not connected by default. The control method includes: determining the current power supply... The system measures the total electricity load as indicated by peak demand. When the total electricity load meets a first preset condition, the system switches to a first operating mode. In the first operating mode, the pipeline between the first coal-fired boiler and the third turbine unit is connected, as is the pipeline between the second coal-fired boiler and the third turbine unit. When the total electricity load meets a second preset condition, the system switches to a second operating mode. In the second operating mode, the pipeline between the first coal-fired boiler and the first turbine unit is connected, as is the pipeline between the second coal-fired boiler and the second turbine unit. When the total electricity load meets a second preset condition, the system switches to a second operating mode. When the electrical load meets the third preset condition, the system is switched to the third operating mode. In the third operating mode, the pipeline between the first coal-fired boiler and the first turbine unit is connected, as are the pipelines between the second coal-fired boiler and the second and third turbine units. When the total electrical load meets the fourth preset condition, the system is switched to the fourth operating mode. In the fourth operating mode, the pipeline between the first coal-fired boiler and the first and third turbine units is connected, as are the pipelines between the second coal-fired boiler and the second and third turbine units. The electrical load requirements corresponding to the first, second, third, and fourth preset conditions increase sequentially. The first rated power of the first turbine unit is configured based on the first minimum stable combustion load of the first coal-fired boiler. The second rated power of the second turbine unit is configured based on the second minimum stable combustion load of the second coal-fired boiler. The third rated power of the third turbine unit is configured based on the following information: the first rated power, the second rated power, the first rated evaporation capacity of the first coal-fired boiler, and the second rated evaporation capacity of the second coal-fired boiler.

[0007] The thermal system control method for deep peak shaving according to embodiments of the present invention can flexibly adapt to a wide range of power peak shaving demands by dynamically switching the pipeline connection mode between the coal-fired boiler and the steam turbine unit in a one-boiler-two-turbine operating system. By optimizing the operating mode and load matching, it ensures that the boiler always operates within a relatively efficient and stable load range, thereby improving the economy, reliability, and peak shaving depth of the entire system.

[0008] According to some embodiments of the present invention, the first preset condition includes: the total power load is less than or equal to a first threshold, and the switching duration is greater than or equal to a first duration, wherein the switching duration is the time interval between the current moment and the moment of the last switching of the operating mode; the second preset condition includes: the total power load is greater than a third threshold and less than or equal to a fourth threshold, and the switching duration is greater than or equal to the first duration; the third preset condition includes: the total power load is greater than a fifth threshold and less than or equal to a sixth threshold, and the switching duration is greater than or equal to the first duration; the fourth preset condition includes: the total power load is greater than a seventh threshold, and the switching duration is greater than or equal to the first duration; the values ​​of the first threshold, the third threshold, the fourth threshold, the fifth threshold, the sixth threshold, and the seventh threshold increase sequentially; The method further includes maintaining the current operating mode unchanged when the total power load meets any of the following conditions: the total power load is greater than the first threshold and less than or equal to the third threshold, the total power load is greater than the fourth threshold and less than or equal to the fifth threshold, and the total power load is greater than the sixth threshold and less than or equal to the seventh threshold.

[0009] According to some embodiments of the present invention, the method further includes: using a quantum particle swarm optimization algorithm to determine a load allocation scheme that meets constraints with the objective of minimizing the total coal consumption of the first coal-fired boiler and the second coal-fired boiler, wherein the constraints are related to the current operating mode and are used to ensure that the total power generation of the system meets the total power load requirements while meeting safety requirements; and adjusting the main steam pressure of the first coal-fired boiler and the second coal-fired boiler, as well as the output power of the currently connected turbine unit, according to the load allocation scheme.

[0010] According to some embodiments of the present invention, the constraints include: the total output power of the turbine units currently connected to the first coal-fired boiler and the second coal-fired boiler meets the total power load demand; the sum of the steam output of the first coal-fired boiler and the second coal-fired boiler is equal to the amount of steam required to reach the output power of the turbine units that are turned on; the steam output of each of the first coal-fired boiler and the second coal-fired boiler satisfies the constraints of the current operating mode with respect to the output power of the connected turbine units; the steam output of the first coal-fired boiler is between the minimum steam output and the rated evaporation capacity corresponding to the first coal-fired boiler; and the steam output of the second coal-fired boiler is between the minimum steam output and the rated evaporation capacity corresponding to the second coal-fired boiler.

[0011] According to some embodiments of the present invention, the constraints further include: the load change rate of the first coal-fired boiler and the second coal-fired boiler is less than or equal to an eighth threshold, the ramp rate of the connected turbine units is less than or equal to a ninth threshold, and the steam header pressure corresponding to the first coal-fired boiler and the second coal-fired boiler is less than or equal to a tenth threshold.

[0012] According to some embodiments of the present invention, before switching the system to any operating mode, the method further includes: predicting load change curves based on historical load data, power grid dispatching plans, and weather forecasts; determining the operating mode to be switched and the expected mode switching duration based on the load change curves and the first preset condition, the second preset condition, the third preset condition, and the fourth preset condition; before the mode switching duration, controlling the first coal-fired boiler and the second coal-fired boiler to enter a first preparatory switching state, and / or controlling one or more of the first turbine unit, the second turbine unit, and the third turbine unit to enter a second preparatory switching state, wherein the first preparatory switching state and the second preparatory state are associated with the mode to be switched, the first preparatory switching state is a transitional state of the first coal-fired boiler and the second coal-fired boiler between the current operating mode and the operating mode to be switched, and the second preparatory switching state is a transitional state of the first turbine unit, the second turbine unit, and the third turbine unit between the current operating mode and the operating mode to be switched.

[0013] According to some embodiments of the present invention, controlling the first coal-fired boiler and the second coal-fired boiler to enter a first pre-switching state includes: slowly adjusting the combustion and steam parameters of the first coal-fired boiler and the second coal-fired boiler so that the outlet steam state matches the state required by the operating mode to be switched.

[0014] According to some embodiments of the present invention, controlling one or more of the first turbine unit, the second turbine unit, and the third turbine unit to enter a second pre-switching state includes: performing low-speed warm-up and vacuuming on the equipment to be started in the first turbine unit, the second turbine unit, and the third turbine unit, and gradually adjusting the main pipe pressure to the range required for the operating mode to be switched; or, gradually transferring the load on the equipment to be shut down in the first turbine unit, the second turbine unit, and the third turbine unit.

[0015] According to a second aspect of the present invention, a thermal system for deep peak shaving includes two coal-fired boilers and three turbine units: a first coal-fired boiler, a second coal-fired boiler, a first turbine unit, a second turbine unit, and a third turbine unit. The first coal-fired boiler is connected to the first turbine unit and the third turbine unit by pipeline, and the second coal-fired boiler is connected to the second turbine unit and the third turbine unit by pipeline. The pipelines are not connected by default. The thermal system can operate as described in the first aspect of the present invention.

[0016] The thermal system for deep peak shaving according to embodiments of the present invention can flexibly adapt to a wide range of power peak shaving demands by dynamically switching the pipeline connection mode between the coal-fired boiler and the steam turbine unit in a one-boiler-two-turbine operation system. By optimizing the operating mode and load matching, it ensures that the boiler always operates within a relatively efficient and stable load range, thereby improving the economy, reliability, and peak shaving depth of the entire system.

[0017] According to some embodiments of the present invention, a control device is also included, the control device comprising a processor, a memory, and a computer program stored in the memory and executable on the processor, wherein when the processor executes the computer program, the thermal system implements the thermal system control method for deep peak shaving as described in the first aspect embodiment of the present invention.

[0018] Additional aspects and advantages of the invention will be set forth in part in the description which follows, and in part will be obvious from the description, or may be learned by practice of the invention. Attached Figure Description

[0019] The above and / or additional aspects and advantages of the present invention will become apparent and readily understood from the description of the embodiments taken in conjunction with the following drawings, in which: Figure 1 This application provides a schematic diagram of the structure of a thermal system for deep peak shaving.

[0020] Figure 2 An exemplary flowchart of the thermal system control method for deep peak shaving provided in this application.

[0021] Figure 3 This is a schematic diagram illustrating the matching of preset conditions and operating modes.

[0022] Figure 4 This is a schematic diagram illustrating the matching of another set of preset conditions with a different operating mode.

[0023] Figure 5 This paper shows a schematic diagram of another thermal system control device for deep peak shaving provided in an embodiment of this application.

[0024] Figure label: 100. Thermal system; 1. Coal-fired boiler system; 11. First coal-fired boiler; 111. First boiler body; 112. First reheater; 12. Second coal-fired boiler; 121. Second boiler body; 122. Second reheater; 2. Steam turbine system; 21. First steam turbine unit; 211. First high-pressure cylinder; 212. First intermediate-pressure cylinder; 213. First low-pressure cylinder; 22. Third steam turbine unit; 221. Third high-pressure cylinder; 222. Third intermediate-pressure cylinder; 223. Third low-pressure cylinder; 23. Second steam turbine unit; 231. Second high-pressure cylinder; 232. Second intermediate-pressure cylinder; 233. Second low-pressure cylinder; 3. Piping connection system; 311. First main pipe; 312. Second main pipe; 321. First connecting pipe; 322. Second connecting pipe; 323. Third connecting pipe; 324. Fourth connecting pipe; 331. First regulating valve; 332. Second regulating valve; 333. Third regulating valve; 334. Fourth regulating valve; 341. First return pipe; 342. Second return pipe; 343. Third return pipe; 344. Mixing box; 351. Inlet regulating valve; 352. Desuperheating and pressure reducing valve; 353. Mechanical vapor recompression system; 4. Thermal system control device; 41. Processor; 42. Memory; 43. Computer instructions. Detailed Implementation

[0025] Embodiments of the present invention are described in detail below. Examples of these embodiments are shown in the accompanying drawings, wherein the same or similar reference numerals denote the same or similar elements or elements having the same or similar functions throughout. The embodiments described below with reference to the accompanying drawings are exemplary and are only used to explain the present invention, and should not be construed as limiting the present invention.

[0026] The following is for reference. Figures 1-5 A thermal system control method for deep peak shaving is described according to an embodiment of the present invention.

[0027] The process of electricity production is the conversion of primary energy into secondary energy by a power plant through a series of power generation devices. There are many types of power plants, such as thermal power plants, hydropower plants, and nuclear power plants. The primary energy structure dictates a pattern dominated by thermal power generation. With increasing pressure on power supply, the operating load of thermal power units in thermal power plants is changing more significantly and frequently. This places higher demands on the stability of the operating status of thermal power unit equipment and means that power plants will face greater challenges in monitoring the condition of their equipment.

[0028] The power plant's thermal system 100 is the core energy conversion system that transforms the chemical energy of fuel into electrical energy. Its function is to ensure the safe and economical operation of the unit through heat transfer and conversion, while also taking into account the needs of start-up, shutdown, and load regulation. For example, the thermal system 100 is responsible for converting the heat energy generated by fuel combustion into steam, driving the steam turbine to rotate, and then driving the generator to generate electricity. The thermal system 100 is typically composed of multiple interconnected devices that work together to realize the functions of the thermal system 100.

[0029] In a traditional coal-fired power plant's thermal system, one boiler corresponds to one steam turbine. The boiler has a "minimum stable combustion load" limitation, typically between 30% and 50% of its design load. If the load falls below this value, the furnace temperature will be too low, leading to unstable combustion, flameout, or even the need for oil-assisted combustion, which is neither safe nor economical. Furthermore, due to uneven electricity consumption, there is often a peak-shaving demand on the power grid, and the one-to-one boiler-to-turbine configuration may result in insufficient peak-shaving depth. Specifically, while a steam turbine can theoretically operate at very low loads, its efficiency will drop sharply, and vibrations may occur. In other words, if the steam turbine supports the boiler at maximum efficiency, then the boiler cannot operate at its minimum stable combustion load, or its operating efficiency will be extremely low. If the steam turbine can support the boiler at its minimum stable combustion load, it indicates that the turbine's power output is relatively small, thus failing to fully utilize the boiler's maximum efficiency.

[0030] For ease of understanding, the following explains some key terms involved in this embodiment: 1. The thermal system 100 for deep peak shaving refers to a novel power generation system proposed in this application. Its core lies in the flexible configuration of steam pipeline connections between two coal-fired boilers and three steam turbine units to adapt to different power load demands. This system aims to optimize the operating efficiency and peak shaving capacity of thermal power units, especially under deep peak shaving conditions.

[0031] 2. A coal-fired boiler is a device that generates high-temperature, high-pressure steam by burning coal. The steam is used to drive a steam turbine unit to generate electricity. In this system, there is a first coal-fired boiler 11 and a second coal-fired boiler 12, which are the core of the steam supply. In any operating mode of this application, both coal-fired boilers are in continuous operation.

[0032] 3. A steam turbine is a device that uses the energy of steam to drive a generator to produce electricity. In this system, there are a first steam turbine, a second steam turbine, and a third steam turbine, which are key to the output of electrical energy. In the various operating modes designed in this application, all three steam turbines may be in operation, or some of the steam turbines may be in operation while some of the turbine units are in shutdown.

[0033] 4. Pipeline connection system 3 refers to the pipeline network used for transporting steam in the thermal system 100. In the thermal system 100 involved in this application, the pipeline between the boiler and the steam turbine is not connected by default, that is, the first regulating valve 331, the second regulating valve, the third regulating valve 333 and the fourth regulating valve 334 are closed. Selective connection can be achieved by opening the corresponding regulating valve or other control mechanism based on the current total power load, thereby forming different operating modes.

[0034] 5. Total electrical load refers to the total power demand that the power grid submits to the power system at a certain moment. This load is the main basis for the decision-making on switching the system operation mode in this application.

[0035] 6. The rated power of a steam turbine unit refers to the maximum electrical power that the steam turbine unit can continuously output under design operating conditions. In this method, the first rated power of the first steam turbine, the second rated power of the second steam turbine, and the third rated power of the third steam turbine are configured based on the stable combustion load and rated evaporation capacity of the two boilers.

[0036] 7. The minimum stable combustion load of a coal-fired boiler refers to the lowest load level that a coal-fired boiler can achieve under the premise of ensuring stable combustion and safe operation. The rated power configuration of each turbine unit in this application will take into account the minimum stable combustion load of the boiler to reduce the possibility of the boiler operating under unstable conditions.

[0037] 8. The rated evaporation capacity of a coal-fired boiler refers to the maximum amount of steam that the boiler can produce per unit time under design operating conditions. This parameter is one of the important bases for configuring the rated power of the steam turbine unit.

[0038] 9. Operating mode refers to a specific combination of pipeline connection methods between the coal-fired boiler and the steam turbine unit provided in this application. This method defines a first operating mode, a second operating mode, a third operating mode, and a fourth operating mode, each corresponding to a specific pipeline connection state and load adaptability range.

[0039] 10. Steam inlet regulating valve, used to regulate steam flow. For example, a steam inlet regulating valve installed before the main steam valve of a steam turbine is used to regulate the steam flow entering the steam turbine to control the unit load and speed. This application can use an electric regulating valve or a pneumatic regulating valve, and the valve body material is preferably high-temperature resistant alloy steel.

[0040] 11. Desuperheating and pressure reducing valve 352: An integrated device that cools and depressurizes high-parameter steam in pipelines to meet the requirements of subsequent processes or equipment. It is typically used in heating, auxiliary steam, and other systems.

[0041] According to a first aspect of the present invention, a control method for a thermal system 100 for deep peak shaving is provided. The thermal system 100 includes two coal-fired boilers and three turbine units. The two coal-fired boilers are a first coal-fired boiler 11 and a second coal-fired boiler 12. The three turbine units are a first turbine unit 21, a second turbine unit 23, and a third turbine unit 22. The first coal-fired boiler 11 is connected to the first turbine unit 21 and the third turbine unit 22 by a pipeline. The second coal-fired boiler 12 is connected to the second turbine unit 23 and the third turbine unit 22 by a pipeline. The pipelines are not connected by default. Control methods include: Determine the total electricity load indicated by the current peak-shaving demand; When the total power load meets the first preset condition, the system is switched to the first operating mode. In the first operating mode, the pipeline between the first coal-fired boiler 11 and the third steam turbine unit 22 is connected, as is the pipeline between the second coal-fired boiler 12 and the third steam turbine unit 22. When the total power load meets the second preset condition, the system is switched to the second operating mode. In the second operating mode, the pipeline between the first coal-fired boiler 11 and the first steam turbine unit 21 is connected, and the pipeline between the second coal-fired boiler 12 and the second steam turbine unit 23 is connected. When the total power load meets the third preset condition, the system is switched to the third operating mode. In the third operating mode, the pipeline between the first coal-fired boiler 11 and the first steam turbine unit 21 is connected, as are the pipelines between the second coal-fired boiler 12 and the second steam turbine unit 23 and the third steam turbine unit 22. When the total power load meets the fourth preset condition, the system will be switched to the fourth operating mode. In the fourth operating mode, the pipeline between the first coal-fired boiler 11 and the first steam turbine unit 21 and the third steam turbine unit 22 will be connected, as will the pipeline between the second coal-fired boiler 12 and the second steam turbine unit 23 and the third steam turbine unit 22. The power load requirements corresponding to the first preset condition, the second preset condition, the third preset condition, and the fourth preset condition increase sequentially. The first rated power of the first turbine unit 21 is configured based on the first minimum stable combustion load of the first coal-fired boiler 11. The second rated power of the second turbine unit 23 is configured based on the second minimum stable combustion load of the second coal-fired boiler 12. The third rated power of the third turbine unit 22 is configured based on the following information: first rated power, second rated power, first rated evaporation capacity of the first coal-fired boiler 11, and second rated evaporation capacity of the second coal-fired boiler 12.

[0042] The thermal system 100 for deep peak shaving provided in this application embodiment can switch between multiple one-boiler-one-turbine modes and one-boiler-two-turbine modes. During periods of high load electricity consumption, all boilers and all steam turbines can operate at full power. During periods of low load electricity consumption, the power plant output can be reduced by "shutting down the boiler without stopping the turbine", thereby greatly improving the system's deep peak shaving capability.

[0043] It should be understood that total electricity load can be obtained in various ways, such as by issuing direct commands from the power grid dispatch center or by calculating it through real-time monitoring of power grid frequency changes. The load data acquisition cycle can be set from 15 seconds to 10 minutes to adapt to different frequency regulation scenarios.

[0044] In the first operating mode, the pipeline between the first coal-fired boiler 11 and the second steam turbine is connected, and the pipeline between the second coal-fired boiler 12 and the second steam turbine is also connected. This means that the steam from both coal-fired boilers is directed to the second steam turbine for power generation.

[0045] In the second operating mode, the pipeline between the first coal-fired boiler 11 and the first steam turbine is connected, and the pipeline between the second coal-fired boiler 12 and the third steam turbine is also connected. In this mode, the two coal-fired boilers independently supply steam to their respective steam turbines to generate electricity.

[0046] In the third operating mode, the pipeline between the first coal-fired boiler 11 and the first steam turbine is connected, while the pipeline between the second coal-fired boiler 12 and the second and third steam turbines is connected. This means that the first coal-fired boiler 11 supplies steam to the first steam turbine, while the second coal-fired boiler 12 supplies steam to both the second and third steam turbines simultaneously.

[0047] In the fourth operating mode, the pipeline between the first coal-fired boiler 11 and the first and second steam turbines is connected, while the pipeline between the second coal-fired boiler 12 and the second and third steam turbines is also connected. In this mode, both coal-fired boilers can supply steam to both steam turbines, achieving maximum power generation capacity.

[0048] This application designs multiple preset conditions to determine whether the total power load has reached a specific level. Different conditions correspond to different operating modes, and these modes increase sequentially according to the power load requirements. For example, when the total power load meets the first preset condition, the system switches to the first operating mode. Similarly, when the total power load meets the second preset condition, the system switches to the second operating mode. And so on, when the total power load meets the third preset condition, the system switches to the third operating mode. And finally, when the total power load meets the fourth preset condition, the system switches to the fourth operating mode. The power load requirements corresponding to the first, second, third, and fourth preset conditions are set to increase sequentially. This incremental relationship ensures that the system can gradually adjust its operating mode to match power demand according to changes in load levels.

[0049] In one implementation, the second rated power of the second steam turbine is configured based on the first rated power of the first steam turbine, the third rated power of the third steam turbine, the first rated evaporation capacity of the first coal-fired boiler 11, and the second rated evaporation capacity of the second coal-fired boiler 12. This configuration serves two purposes: firstly, it ensures that in the first operating mode, the designed output of the second steam turbine matches the minimum load required for stable combustion of the first coal-fired boiler 11 and the second coal-fired boiler 12; secondly, it ensures that in the fourth operating mode, the designed output of the second steam turbine matches the rated evaporation capacity (or maximum evaporation capacity) of the first coal-fired boiler 11 and the second coal-fired boiler 12. These seemingly contradictory matching relationships are achieved through the unique system results of this application. In the first operating mode, even if the first coal-fired boiler 11 and the second coal-fired boiler 12 operate at the minimum stable combustion load, the second steam turbine, which shares the same turbine, can be designed to have a higher rated power than the turbine of a single boiler. In the fourth operating mode, even if the first coal-fired boiler 11 and the second coal-fired boiler 12 operate at full load, the second steam turbine can still operate at high efficiency because the power can be diverted between the first and third steam turbines. In other words, the system of this application, through the combined design of two boilers and three steam turbines, can maximize the boiler capacity and improve the depth of power peak regulation.

[0050] In one implementation, the first rated power of the first steam turbine is configured based on the first minimum stable combustion load of the first coal-fired boiler 11. However, it should be noted that this does not mean that the design output of the first steam turbine is completely matched with the minimum stable combustion load of the first coal-fired boiler 11. This is because in the first operating mode, it is usually sufficient to support the first coal-fired boiler 11 and the second coal-fired boiler 12 to operate at their respective minimum stable combustion loads. Therefore, in the second operating mode, the first rated power can be designed to match the sum of the first minimum stable combustion load and a preset offset value. Similarly, the third rated power of the third steam turbine is configured based on the second minimum stable combustion load of the second coal-fired boiler 12. For example, the third rated power can be designed to match the sum of the second minimum stable combustion load and a preset offset value, which can improve the peak-shaving level.

[0051] This application dynamically switches the pipeline connection between the coal-fired boiler and the steam turbine in a single-boiler, two-turbine operating system, enabling flexible adaptation to a wide range of power peak-shaving demands. This effectively solves the problems faced by traditional thermal power units during deep peak-shaving, such as difficulties in maintaining stable boiler combustion at low loads, decreased unit operating efficiency, and increased equipment wear. By optimizing operating modes and load matching, it ensures that the boiler always operates within a relatively efficient and stable load range, thereby improving the overall system's economy, reliability, and peak-shaving depth.

[0052] In a simplified design approach, the first to fourth preset conditions can be designed as a continuous threshold interval. Figure 3 For example, if the total power load is less than A, switch to the first operating mode; if the total power load is between A and B, switch to the second operating mode; if the total power load is between B and C, switch to the third operating mode; and if the total power load is greater than C, switch to the fourth operating mode.

[0053] According to an embodiment of the present invention, the control method for a thermal system 100 for deep peak shaving can flexibly adapt to a wide range of power peak shaving demands by dynamically switching the pipeline connection mode between the coal-fired boiler and the steam turbine unit in a single-boiler, two-turbine operating system. By optimizing the operating mode and load matching, it ensures that the boiler always operates within a relatively efficient and stable load range, thereby improving the economy, reliability, and peak shaving depth of the entire system.

[0054] According to some embodiments of the present invention, the first preset condition includes: The total power load is less than or equal to the first threshold, and the switching time is greater than or equal to the first duration. The switching time is the time interval between the current moment and the last time the operating mode was switched. The second preset condition includes: the total power load is greater than the third threshold and less than or equal to the fourth threshold, and the switching time is greater than or equal to the first time. The third preset condition includes: the total power load is greater than the fifth threshold and less than or equal to the sixth threshold, and the switching time is greater than or equal to the first time. The fourth preset condition includes: the total power load is greater than the seventh threshold, and the switching time is greater than or equal to the first time. The values ​​of the first threshold, third threshold, fourth threshold, fifth threshold, sixth threshold, and seventh threshold increase sequentially.

[0055] The method also includes maintaining the current operating mode unchanged when the total power load meets any of the following conditions: the total power load is greater than the first threshold and less than or equal to the third threshold, the total power load is greater than the fourth threshold and less than or equal to the fifth threshold, or the total power load is greater than the sixth threshold and less than or equal to the seventh threshold.

[0056] The first, third, fourth, fifth, sixth, and seventh thresholds are preset values ​​used to divide different load ranges. These thresholds can be set based on historical operating data, system capacity, equipment characteristics, and economic analysis. For example, they can be determined based on long-term load forecasts and unit operating cost curves to ensure the system operates at its optimal configuration under different load levels. Furthermore, these thresholds can be dynamically optimized using expert systems or machine learning algorithms to adapt to changes in the power grid operating environment, such as adjustments based on seasonal load changes or the proportion of renewable energy integration. Switching time refers to the time elapsed since the last successful mode switch and system stabilization. This time can be precisely recorded using an internal system timer and reset after each successful mode switch. For example, a dedicated timestamp recording module can be set up to record the current time as the starting point after the mode switch command is issued and confirmed. The second threshold is the minimum time interval used to limit the frequency of mode switches. This threshold can be determined based on the dynamic response characteristics of the unit equipment during startup, shutdown, warm-up, and cooling, as well as the time required for system stabilization. For example, it can be empirically set based on the boiler's heating rate, the turbine's warm-up time, and the time required for the entire system to reach stable output. Furthermore, this threshold can be optimized through simulation analysis or actual operational testing to maximize the system's response flexibility while ensuring system stability. When the total power load meets any of the following conditions: "greater than the first threshold and less than or equal to the third threshold," "greater than the fourth threshold and less than or equal to the fifth threshold," or "greater than the sixth threshold and less than or equal to the seventh threshold," the system will maintain its current operating mode. These conditions define the "hysteresis" or "no-switching zone" within the load fluctuation range.

[0057] by Figure 4For example, there is a hysteresis between the first and third thresholds, between the fourth and fifth thresholds, and between the sixth and seventh thresholds. When the total power load falls within these hysteresis intervals, no mode switching occurs. In other words, when the system is in a certain operating mode, even if the total power load slightly exceeds the typical load range of the current mode, as long as it falls within these preset hysteresis intervals, the system will not immediately trigger mode switching. This mechanism can be implemented by introducing state-preserving variables into the control logic; that is, when determining whether to switch modes, not only the current load conditions but also the current operating mode state of the system are considered.

[0058] Through the above technical solution, this application introduces switching time as a judgment condition and sets a load hysteresis interval when switching operating modes based on total power load. Specifically, the system will only consider switching modes when the total power load meets the requirements of a specific interval and the time elapsed since the last mode switch is greater than or equal to a preset second threshold. Simultaneously, within certain load intervals, even if the load fluctuates, the system will maintain the current operating mode. This design effectively avoids frequent mode switching caused by short-term, small load fluctuations, thereby significantly reducing the mechanical stress, thermal stress, and wear caused by unit equipment startup, shutdown, and load adjustment operations, and extending the service life of the equipment. Furthermore, by forcing the system to maintain stable operation for a period after each switch, it ensures that the system has sufficient time to reach a new stable operating condition, avoiding switching again before the system is stable, thus improving the operational stability and reliability of the entire one-boiler-two-unit switching system. This mechanism, while ensuring safe system operation, also optimizes operational economy and reduces fuel consumption and auxiliary equipment energy consumption caused by frequent switching.

[0059] According to some embodiments of the present invention, it further includes: With the goal of minimizing the total coal consumption of the first coal-fired boiler 11 and the second coal-fired boiler 12, the quantum particle swarm optimization algorithm is used to determine the load allocation scheme when the constraints are met. The constraints are related to the current operating mode and are used to ensure that the total power generation of the system meets the total power load requirements while meeting safety requirements. Adjust the main steam pressure of the first coal-fired boiler 11 and the second coal-fired boiler 12, as well as the output power of the currently connected steam turbine unit, according to the load distribution scheme.

[0060] In some embodiments described above in this application, switching to different operating modes based on the total electrical load is proposed to adapt to different load demands. However, in the implementation process, there are optimization deficiencies in how to efficiently allocate the load among boilers to minimize total coal consumption while ensuring safety constraints, such as keeping the boiler steam output between minimum and rated, and meeting the total power generation demand. To address this, this application further proposes using a quantum particle swarm optimization algorithm to determine a load allocation scheme that meets the constraints, with the goal of minimizing the total coal consumption of the first coal-fired boiler 11 and the second coal-fired boiler 12. The constraints are related to the current operating mode and are used to ensure that the total power generation of the system meets the total electrical load requirements while satisfying safety requirements. The main steam pressure of the first coal-fired boiler 11 and the second coal-fired boiler 12, as well as the output power of the currently connected steam turbine, are adjusted according to the load allocation scheme.

[0061] Specifically, the method proposed in this application takes minimizing the total coal consumption of the first coal-fired boiler 11 and the second coal-fired boiler 12 as its core optimization objective. Minimizing total coal consumption means finding an optimal load distribution point while meeting the total electricity load demand, so that the operating efficiency of the two boilers achieves the best combination, thereby maximizing economic benefits. This can usually be achieved by establishing a mathematical model between boiler coal consumption and output load, such as a polynomial fitting curve or a model based on thermodynamic calculations, and using this as the objective function of the optimization algorithm.

[0062] To achieve this goal, this application employs the quantum particle swarm optimization algorithm. Quantum particle swarm optimization is an intelligent optimization algorithm that combines particle swarm optimization with the principles of quantum mechanics. By introducing the concept of quantum states, it allows particles to exist in the search space in a probability distribution, enhancing particle diversity and global search capability, thereby effectively avoiding getting trapped in local optima. The specific implementation of the algorithm is not limited here. Besides quantum particle swarm optimization, other advanced intelligent optimization algorithms can also be used, such as genetic algorithms, simulated annealing, differential evolution, or ant colony optimization. These algorithms all possess the ability to handle complex nonlinear optimization problems, but quantum particle swarm optimization may have advantages in convergence speed and optimization accuracy.

[0063] Through the aforementioned optimization algorithm, this application can determine a load allocation scheme that meets the constraints. Specifically, the scheme includes the steam output or heat load that the first coal-fired boiler 11 and the second coal-fired boiler 12 should each bear, and the power output that the turbines connected to them should each output. The optimization algorithm iteratively searches for the load combination that minimizes total coal consumption within a space that satisfies all preset constraints, and finally outputs this optimal combination as the load allocation scheme.

[0064] Based on the determined load distribution scheme, this application further adjusts the main steam pressure of the first coal-fired boiler 11 and the second coal-fired boiler 12. Adjusting the main steam pressure is typically achieved by controlling parameters such as the boiler's fuel quantity, forced draft, induced draft, and feedwater flow. For example, increasing the fuel quantity and forced draft can improve combustion intensity, thereby increasing steam production and main steam pressure. A closed-loop control system can be used to monitor the main steam pressure in real time and, based on the target pressure value given by the load distribution scheme, automatically adjust the boiler's operating parameters using a PID controller or other advanced control strategies to achieve the target pressure.

[0065] According to some embodiments of the present invention, the constraints include: The total output power of the turbine units currently connected to the first coal-fired boiler 11 and the second coal-fired boiler 12 meets the total power load demand. The sum of the steam output of the first coal-fired boiler 11 and the second coal-fired boiler 12 is equal to the amount of steam required to reach the output power of the turbine units that are turned on. The steam output of the first coal-fired boiler 11 and the second coal-fired boiler 12 respectively meets the constraints of the current operating mode with respect to the output power of the connected turbine units. The steam output of the first coal-fired boiler 11 is between the minimum steam output and the rated evaporation capacity corresponding to the first coal-fired boiler 11, and the steam output of the second coal-fired boiler 12 is between the minimum steam output and the rated evaporation capacity corresponding to the second coal-fired boiler 12.

[0066] The constraints are related to the current operating mode and are used to ensure that the total power generation of the system meets the total power load requirements while satisfying safety requirements. These constraints are dynamic and are adjusted according to the current operating mode of the system (e.g., operating mode 1, operating mode 2, operating mode 3, operating mode 4, etc.). They typically include the boiler's minimum stable combustion load, maximum evaporation rate, turbine's minimum technical output, maximum output, steam parameter (pressure, temperature) range, equipment ramp rate limits, and pipeline flow capacity, etc. Ensuring safety requirements means avoiding equipment overload operation, preventing combustion instability, and maintaining steam parameters within safe ranges. Meeting the total power load requirements means that the total power generation of all connected turbines must be equal to or slightly higher than the total power load indicated by the current peak power demand.

[0067] Simultaneously, this application also adjusts the output power of the currently connected steam turbines according to the load allocation scheme. The output power of the steam turbine is mainly controlled by adjusting the opening degree of the steam inlet valve. The larger the opening degree of the steam inlet valve, the greater the steam flow into the steam turbine, and the higher the output power. Steam turbines are usually equipped with load regulators, which automatically adjust the opening degree of the steam inlet valve according to the frequency deviation of the power grid or dispatch instructions to achieve the target output power. After receiving the load allocation scheme, the system will send the target output power instruction to the corresponding steam turbine load regulator.

[0068] The load allocation scheme based on the quantum particle swarm optimization algorithm upgrades the single-boiler, two-turbine switching system into a fully automated intelligent system capable of real-time self-optimization and pursuing optimal economic operation. This scheme aims to minimize the total coal consumption of the first coal-fired boiler 11 and the second coal-fired boiler 12. Utilizing the powerful global search capability of the quantum particle swarm optimization algorithm, it quickly and accurately determines the optimal load allocation scheme while satisfying various constraints related to the current operating mode (including boiler combustion stability boundary, minimum turbine output, and pipeline flow capacity). This ensures that the system operates in the most economical way under any given total power load command, directly translating the system's flexibility potential into significant economic benefits. Specifically, the optimization variables of this scheme include mode selection, boiler load (determining main steam pressure), and turbine power generation. These variables have complex coupling relationships, and the objective function (total coal consumption) exhibits strong nonlinear characteristics. Compared to traditional optimization methods or allocation methods based on empirical rules, which are prone to local optima, this scheme, through the quantum particle swarm optimization algorithm, effectively avoids local optima and finds a globally optimal or near-global optimal solution. More importantly, this scheme simultaneously optimizes both the boiler side (main steam pressure) and the turbine side (output power). This means the algorithm can discover counterintuitive but more optimal operating points, such as "slightly increasing the pressure of one boiler while decreasing the pressure of another, and simultaneously adjusting the power distribution of the three turbines to achieve an overall reduction in coal consumption," thus realizing true synergistic optimization across the entire machine-boiler-electric system. Ultimately, based on the determined load distribution scheme, the main steam pressures of the first coal-fired boiler 11 and the second coal-fired boiler 12, as well as the output power of the currently connected turbines, are precisely adjusted. This significantly reduces fuel consumption and improves the overall economic efficiency and effectiveness of the operation while ensuring safe system operation and meeting total power load requirements.

[0069] According to some embodiments of the present invention, the constraints also include: the load change rate of the first coal-fired boiler 11 and the second coal-fired boiler 12 is less than or equal to an eighth threshold, the ramp rate of the connected steam turbine units is less than or equal to a ninth threshold, and the steam header pressure corresponding to the first coal-fired boiler 11 and the second coal-fired boiler 12 is less than or equal to a tenth threshold.

[0070] The load change rate of the first coal-fired boiler 11 and the second coal-fired boiler 12 refers to the change in the output power or steam volume of the boiler per unit time. In actual operation, the load change rate of the boiler is limited by factors such as its combustion system, water circulation system, and thermal inertia. Setting an eighth threshold aims to limit rapid fluctuations in boiler load to prevent problems such as unstable combustion, furnace coking, and water circulation instability, while avoiding damage to the boiler body and heating surfaces due to excessive thermal stress, thereby ensuring the safe and stable operation of the boiler under deep peak shaving or rapid load change conditions. Specifically, the rate of change of the outlet steam flow or fuel consumption of the first coal-fired boiler 11 and the second coal-fired boiler 12 can be monitored in real time, calculated within a preset time window, and compared with the eighth threshold. If the calculated rate of change exceeds the eighth threshold, the optimization algorithm will adjust the load distribution scheme to ensure that the boiler operates within a safe range. In addition, the load change rate of the boiler can also be indirectly limited by controlling the adjustment speed of the boiler's fuel supply, air supply, induced draft, and feedwater, keeping it within the eighth threshold.

[0071] The ramp rate of a connected steam turbine refers to the rate at which the turbine's output power increases or decreases per unit time. During startup, shutdown, or rapid load changes, the internal components of a steam turbine experience significant thermal stress. Setting a ninth threshold aims to limit rapid changes in the turbine's output power, preventing deformation, cracking, or damage to critical components such as the turbine rotor, cylinders, and blades due to thermal stress concentration or fatigue, thereby ensuring the long-term reliable operation of the turbine. Specifically, this can be achieved by real-time monitoring of the actual output power (e.g., generator active power) of currently connected steam turbines (including one or more of the first, second, and third turbines), calculating its rate of change within a preset time window, and comparing it to the ninth threshold. If the calculated rate of change exceeds the ninth threshold, the optimization algorithm will adjust the turbine's load distribution to ensure it operates within a safe range. Furthermore, the ramp rate can also be indirectly limited by controlling the adjustment speed of parameters such as the turbine's main steam valve opening, regulating valve opening, and bypass system, keeping it within the ninth threshold.

[0072] The steam header pressure corresponding to the first coal-fired boiler 11 and the second coal-fired boiler 12 refers to the pressure after the steam generated by the first coal-fired boiler 11 and the second coal-fired boiler 12 converges into the main steam header. The steam header is an important channel connecting the boiler and the turbine, and its pressure directly affects the safety and stability of the entire steam system. Setting a tenth threshold aims to prevent overpressure in the steam system, ensure the safe operation of equipment such as steam pipes, valves, and turbine inlets, and avoid accidents such as pipe rupture, leakage, or other equipment damage due to excessive pressure. At the same time, a stable steam header pressure is also an important prerequisite for the stable operation of the turbine. Specifically, the steam pressure value can be monitored in real time by a high-precision pressure sensor installed on the steam header and compared with the tenth threshold. If the monitored pressure value exceeds the tenth threshold, the optimization algorithm will adjust parameters such as the boiler combustion intensity, feedwater flow rate, or turbine steam inlet to quickly reduce the steam header pressure to a safe range. In addition, safety valves, pressure relief valves, and other protective devices can be set up to automatically open and relieve pressure when the steam header pressure reaches or exceeds the tenth threshold, thereby ensuring the safety of the system.

[0073] By introducing dynamic constraints on the load change rate of the first coal-fired boiler 11 and the second coal-fired boiler 12, the ramp rate of the connected steam turbine, and the steam header pressure, this application effectively solves problems such as boiler combustion instability, turbine mechanical damage, and steam system overpressure that may occur during deep peak shaving and mode switching. These constraints provide a more comprehensive and realistic "feasible region" for the quantum particle swarm optimization algorithm, enabling the algorithm to consider not only minimizing total coal consumption and matching power generation when determining load allocation schemes, but also fully taking into account the dynamic response capability and operational safety of the equipment. Specifically, limiting the boiler load change rate avoids combustion instability and thermal stress damage caused by rapid load fluctuations in the boiler; limiting the turbine ramp rate effectively protects key turbine components from thermal stress fatigue and mechanical damage; and limiting the steam header pressure fundamentally eliminates the risk of steam system overpressure, ensuring the integrity and reliability of the entire steam power system. Therefore, the technical solution proposed in this application can ensure that the one-boiler-two-machine switching operation system can achieve safer, more stable and more efficient operation under various operating modes, especially under rapid load changes or deep peak shaving conditions, and significantly improve the reliability and flexibility of the system.

[0074] In some of the solutions mentioned above in this application, a method for switching to different operating modes based on the total power load is proposed. However, in this process, direct switching may cause the boiler and turbine to be out of sync during the switching process, resulting in system shock, efficiency loss or equipment damage. This is because switching requires time for the equipment to adjust to the new state, and the lack of a preparatory mechanism will increase the operational risk.

[0075] According to some embodiments of the present invention, the method further includes, before switching the system to any operating mode: Based on historical load data, power grid dispatching plans, and weather forecasts, predict load change curves; Based on the load change curve and the first, second, third, and fourth preset conditions, determine the operating mode to be switched and the expected mode switching time. Before the mode switching time point, the first coal-fired boiler 11 and the second coal-fired boiler 12 are controlled to enter the first pre-switching state, and / or one or more of the first turbine unit 21, the second turbine unit 23, and the third turbine unit 22 are controlled to enter the second pre-switching state. The first pre-switching state and the second pre-switching state are associated with the mode to be switched. The first pre-switching state is the transition state between the current operating mode and the operating mode to be switched for the first coal-fired boiler 11 and the second coal-fired boiler 12. The second pre-switching state is the transition state between the current operating mode and the operating mode to be switched for the first turbine unit 21, the second turbine unit 23, and the third turbine unit 22.

[0076] Predicting load change curves aims to obtain future electricity demand trends in advance, providing a basis for decision-making regarding subsequent operational mode switching. This can be achieved through methods including, but not limited to: one approach is based on statistical models, utilizing historical load data and combining time series analysis methods (such as ARIMA models and exponential smoothing) or regression analysis to predict future loads, and incorporating external variables from power grid dispatching plans and weather forecasts into the model for correction. Another approach is based on machine learning methods, employing deep learning models (such as recurrent neural networks (RNNs) and long short-term memory networks (LSTMs)) or ensemble learning models to learn complex nonlinear relationships from large amounts of historical load data, power grid dispatching instructions, and weather data, thereby generating more accurate load prediction curves.

[0077] When determining the operating mode to be switched to and the expected switching time, this step aims to intelligently plan future operating modes and their switching timing based on predicted load trends and preset operating mode switching conditions. This can be achieved, but is not limited to: one approach involves threshold comparison and time point identification. The predicted load change curve is compared in real-time or periodically with load thresholds defined by a first, second, third, and fourth preset condition. When the predicted load curve crosses a load threshold of a preset condition, a potential mode switching point is identified, and the mode to be switched to and the expected switching time are determined. Another approach uses optimization algorithms for decision-making. Combining the economic and safety objectives of system operation, optimization algorithms (such as dynamic programming and heuristic algorithms) are used to find the optimal mode switching sequence and corresponding time points from the predicted load change curve, while satisfying preset conditions, comprehensively considering the costs and benefits of different mode switching methods.

[0078] Before the mode switching time, the first coal-fired boiler 11 and the second coal-fired boiler 12 are controlled to enter the first pre-switching state, and / or one or more of the first steam turbine, the second steam turbine, and the third steam turbine are controlled to enter the second pre-switching state. This aims to pre-process the relevant equipment before the mode switching occurs, gradually bringing its state closer to the state required by the target mode, thereby ensuring the smoothness, safety, and efficiency of the switching process. For the pre-switching of boilers, if the mode to be switched requires an increase in load, the combustion intensity can be slowly increased in advance, the feedwater flow rate can be adjusted, and the fuel supply can be increased, so that its steam parameters gradually approach the high load state required by the target mode; if the mode to be switched requires a decrease in load or shutdown, the combustion intensity can be slowly decreased in advance, and the air volume can be adjusted, so that its steam parameters gradually decrease. For turbine preparation switching, for turbines to be started, low-speed warm-up, vacuuming, and establishing lubricating oil system pressure can be performed in advance to meet the starting conditions; for turbines to be shut down, load transfer, gradual speed reduction, and cooling can be performed in advance to ensure safe shutdown; for turbines that need load adjustment, valve opening, speed, and other parameters can be adjusted in advance to gradually bring their output power closer to the load required for the target mode.

[0079] The first and second pre-switch states are associated with the mode to be switched to, ensuring the targeted and effective nature of the pre-switch operations. Different switching modes have different requirements for the boiler and turbine states, therefore the pre-switch states should also differ. This association is achieved through preset control logic or lookup tables, automatically selecting the appropriate pre-switch operation sequence and parameter settings based on the target mode. The first pre-switch state is not the final operating state, but an intermediate state set up for a smooth transition. In this state, the boiler's various operating parameters will be adjusted in a planned and controlled manner within a certain period of time according to the requirements of the target mode to avoid sudden parameter changes impacting the equipment. Similarly, the second pre-switch state is also a transitional stage. In this stage, the turbine's operating parameters will be adjusted according to the requirements of the target mode to ensure its safe and smooth entry into or exit from operation.

[0080] In summary, this application, based on the switching of the one-boiler-two-turbine operation mode according to the total power load, introduces a forward-looking mode switching preparation mechanism. By comprehensively analyzing historical load data, power grid dispatch plans, and weather forecasts, it can accurately predict future load change trends and determine the operating mode to be switched to and the precise mode switching time in advance. Furthermore, before the actual switch occurs, the system can pre-control the first coal-fired boiler 11 and the second coal-fired boiler 12 to enter a first pre-switching state, and / or control one or more of the first, second, and third steam turbines to enter a second pre-switching state. These pre-switching states are transitional states customized according to the specific requirements of the mode to be switched to, enabling the boiler and turbine operating parameters to be smoothly and gradually adjusted to a level matching the target mode. This advance preparation effectively avoids problems such as system shocks, sudden efficiency drops, and increased equipment wear that may occur during mode switching due to equipment mismatch. For example, before switching modes requiring increased load, the boiler can be slowly heated and pressurized in advance, and the turbine can be warmed up beforehand. This allows for a rapid and smooth response to load demands during the switchover, reducing thermal and mechanical stresses caused by equipment startup or sudden load changes. Conversely, before switching modes requiring reduced load or shutdown, the equipment can be systematically deloaded or cooled to ensure safe shutdown. This not only significantly improves the smoothness and safety of the transition between different operating modes in the entire boiler-two-turbine switching system, reducing operational risks and maintenance costs, but also reduces energy loss by optimizing the switching process, improving the overall system operating efficiency and flexibility in responding to grid dispatch. This enables thermal power units to better adapt to the demands of deep peak shaving and rapid response power systems.

[0081] According to some embodiments of the present invention, controlling the first coal-fired boiler 11 and the second coal-fired boiler 12 to enter a first pre-switching state includes: Slowly adjust the combustion and steam parameters of the first coal-fired boiler 11 and the second coal-fired boiler 12 to match the outlet steam state with the state required for the operating mode to be switched.

[0082] For example, if it is necessary to increase the boiler steam output, the standby coal mill can be started for warm-up (if applicable), and the coal feed rate can be slowly increased (the increase rate is, for example, 2 t / h / min). The primary and secondary air volumes can be increased simultaneously to maintain an oxygen content of 3.5-4.0%. The main steam pressure can be slowly increased from 9.0 MPa to 12.0 MPa (sliding pressure operation) to maintain a stable drum water level and control the steam temperature change rate to <1.5℃ / min. As another example, if it is necessary to reduce the boiler steam output, the coal feed rate can be slowly reduced (the coal feed rate reduction rate is, for example, 1.5 t / h / min) to maintain the drum water level and prevent false water levels from causing MFT. The steam temperature can be reduced (the steam temperature drop rate is controlled to <1.2℃ / min) and stabilized when the output of the coal-fired boiler drops to the target value (e.g., 55 t / h).

[0083] Specifically, "slow adjustment" refers to gradually changing the boiler's operating parameters at a preset, small rate of change over a certain time period, rather than instantaneous or drastic jumps. This aims to avoid system shocks and instability caused by rapid parameter changes. "Combustion parameters" typically include fuel supply, primary air volume, secondary air volume, induced draft volume, and furnace pressure, which directly affect the boiler's combustion efficiency and heat load. For example, the fuel and air supply can be controlled by adjusting the coal feeder speed and the opening of each fan, thus affecting the combustion intensity. "Steam parameters" mainly refer to the main steam pressure, main steam temperature, and reheat steam temperature at the boiler outlet, which directly determine the steam quality and energy. For example, the steam pressure and temperature can be controlled by adjusting the feedwater flow rate, combustion intensity, and the amount of desuperheating water injected. In practice, slow adjustment can be achieved by setting upper limits for the parameter change rate; for example, the main steam pressure change per minute should not exceed a preset value, and the main steam temperature change per minute should not exceed a preset value. Alternatively, a phased adjustment strategy can be adopted, breaking down the total adjustment into multiple small steps, with sufficient stabilization time between each step. Simultaneously, "matching the outlet steam state with the state required by the operating mode to be switched" means that the physical characteristics (mainly including steam pressure and temperature) of the steam generated at the outlet of the first coal-fired boiler 11 and the second coal-fired boiler 12 should meet or closely approximate the steam pressure and temperature conditions required for the normal startup, operation, or load stabilization of the turbines connected to the boilers (e.g., the first turbine, the second turbine, and the third turbine) after the system switches to the target operating mode. Different turbines or different operating loads may have different requirements for the steam state. For example, if the mode to be switched requires starting a turbine, the boiler outlet steam state should meet the warm-up and start-up requirements of that turbine; if the mode to be switched requires maintaining the stable operation of existing turbines, the boiler outlet steam state should be adapted to the current load demand of the turbines. Matching can be achieved by: determining the target steam pressure and temperature according to a preset operating mode parameter table; or by dynamically adjusting the boiler outlet steam parameters to meet the requirements by monitoring the operating status or start-up needs of the turbine to be connected in real time.

[0084] By employing the aforementioned technical solution, the combustion and steam parameters of the first coal-fired boiler 11 and the second coal-fired boiler 12 are slowly and specifically adjusted before the system switches operating modes. This effectively avoids drastic fluctuations in steam pressure and temperature caused by rapid parameter changes. This ensures a smooth transition of the boiler outlet steam state and precise matching with the operating requirements of the turbine connected to the new operating mode, significantly reducing potential problems such as unstable steam quality, excessive equipment thermal stress, and decreased combustion efficiency during the switching process. Therefore, this application ensures the safety, stability, and reliability of the mode switching process, reduces energy loss and equipment wear during switching, and ultimately improves the operating efficiency and economy of the entire one-boiler-two-turbine switching system.

[0085] According to some embodiments of the present invention, controlling one or more of the first turbine unit 21, the second turbine unit 23, and the third turbine unit 22 to enter a second pre-switching state includes: performing low-speed warm-up and vacuuming on the equipment to be started in the first turbine unit 21, the second turbine unit 23, and the third turbine unit 22, and gradually adjusting the main pipe pressure to the range required for the operating mode to be switched; or, gradually transferring the load on the equipment to be shut down in the first turbine unit 21, the second turbine unit 23, and the third turbine unit 22.

[0086] For example, in the scenario of turbine startup preparation, one or more of the following steps are executed in sequence (the specific execution steps are determined based on the turbine's startup state, which includes cold start, warm start, and hot start): starting the auxiliary oil pump, engaging the turning gear, starting the condensate system, establishing a vacuum, starting the circulating water system, and starting pipe warm-up (introducing a small amount of steam from the main pipe at a heating rate of <5℃ / min); As another example, in the scenario of turbine shutdown preparation, one or more of the following steps are executed in sequence (the specific execution steps are determined based on the turbine's startup state): performing load transfer by reducing the turbine load at a rate of 2MW / min while simultaneously increasing the load of another turbine that does not need to be shut down (1MW / min) to achieve load transfer; stopping the reduction when the turbine load reaches the target value and maintaining this state for 10 minutes to ensure uniform rotor temperature. Specifically, for equipment awaiting startup, the steps to enter the second pre-switching state include low-speed warm-up, vacuuming, and gradual adjustment of the mains pressure. Low-speed warm-up refers to the process of slowly and evenly heating the turbine rotor and cylinder at low speeds before startup by introducing a small amount of steam or using an auxiliary heating system. This process aims to eliminate temperature differences between components and prevent deformation or damage caused by concentrated thermal stress. For example, this can be achieved by controlling the flow rate and temperature of the warm-up steam, or by using a turning gear to slowly rotate the rotor in conjunction with cylinder heating, ensuring uniform heating of all components. Another approach is to monitor the temperature of various parts of the turbine in real time during warm-up, especially the temperature difference between the rotor and cylinder, and dynamically adjust the warm-up rate based on the monitoring results to meet the temperature rise curve requirements specified by the equipment manufacturer. Vacuuming refers to the process of using vacuum equipment (such as a steam ejector or vacuum pump) to remove air and non-condensable gases from the condenser and turbine exhaust side before startup, establishing and maintaining a vacuum within the condenser. This operation is crucial for ensuring efficient turbine operation because establishing a vacuum increases the expansion ratio of steam within the turbine, improving thermal efficiency. Specifically, this can be achieved by activating a multi-stage steam ejector group or using a mechanical vacuum pump to evacuate the condenser until the condenser pressure reaches the preset vacuum start-up value. During the vacuuming process, the condenser vacuum level must be continuously monitored and kept stable within the target range to prevent air leakage from affecting subsequent startup. Gradually adjusting the main steam header pressure to the required range for the desired operating mode refers to smoothly adjusting the main steam header pressure from its current state to the pressure level required for the new operating mode during turbine startup or mode switching. This process aims to avoid drastic fluctuations in steam parameters that could impact the turbine and piping system. For example, the main steam header pressure can be smoothly regulated by precisely controlling the boiler combustion rate and feedwater flow rate to gradually increase or decrease steam generation. Another approach is to adjust the main steam bypass valve or turbine main steam valve opening to gradually guide the header pressure to the target value while maintaining steam flow, and to monitor the pressure change rate in real time to ensure it remains within the allowable range. For equipment awaiting shutdown, the steps to enter the second pre-switching state include a gradual load transfer. Gradual load transfer refers to smoothly and progressively transferring the generating load it bears to other operating generator units or the power grid before the turbine is shut down. This process aims to avoid impacting grid stability and the turbine itself due to sudden load unloading. For example, the control system can be coordinated to instruct other grid-connected units to increase output as the load on the turbine awaiting shutdown gradually decreases, maintaining a balance between total power generation and grid demand. Another approach is for operators to slowly close the turbine's main steam valve according to grid dispatch instructions, gradually reducing steam flow to allow the unit's output to decrease smoothly until complete unloading, while closely monitoring the stability of grid frequency and voltage.

[0087] By employing the aforementioned technical solutions, during system operation mode switching, issues such as equipment thermal stress, pressure fluctuations, and uneven load transfer caused by improper turbine startup or shutdown operations can be effectively avoided. Specifically, for turbines awaiting startup, low-speed warm-up and vacuuming operations ensure uniform heating of the turbine rotor and cylinder, reducing thermal stress accumulation and establishing a favorable vacuum environment, laying the foundation for efficient unit startup. Based on this, gradually adjusting the mains pressure allows for a smooth transition of steam parameters, avoiding shocks to the turbine. For turbines awaiting shutdown, gradual load transfer avoids the impact of sudden unit unloading on grid stability and reduces thermal shock during turbine shutdown. These refined pre-switching operations make the entire mode switching process smoother and safer, significantly reducing equipment wear, extending equipment lifespan, and improving the reliability and flexibility of power system operation. This effectively solves the problems of thermal stress, pressure fluctuations, or uneven load transfer that may occur during equipment startup or shutdown during mode switching.

[0088] Figure 5 This illustration shows a schematic diagram of another thermal system control device 4 for deep peak shaving provided in an embodiment of this application. This device can be applied to, for example... Figure 1 The control unit of the thermal system 100 shown includes: at least one processor 41, a memory 42, and computer instructions 43 stored in the memory 42 and executable on the at least one processor 41, wherein the processor 41 executes the computer instructions 43 to implement the steps in any of the above method embodiments.

[0089] According to a second aspect embodiment of the present invention, a thermal system 100 for deep peak shaving includes two coal-fired boilers and three turbine units: a first coal-fired boiler 11, a second coal-fired boiler 12, a first turbine unit 21, a second turbine unit 23, and a third turbine unit 22. The first coal-fired boiler 11 is connected to the first turbine unit 21 and the third turbine unit 22 by pipeline, and the second coal-fired boiler 12 is connected to the second turbine unit 23 and the third turbine unit 22 by pipeline. The pipelines are not connected by default. The thermal system 100 can operate as described in the first aspect embodiment of the present invention.

[0090] The first coal-fired boiler 11 and the second coal-fired boiler 12 are used to generate main steam. As a possible example, the first coal-fired boiler 11 includes, for example, an economizer, a water-cooled wall, at least one low-temperature superheater, a high-temperature superheater, a low-temperature reheater, and a high-temperature reheater. The boiler body 111 includes, for example, an economizer, a water-cooled wall, at least one low-temperature superheater, and a high-temperature superheater. The feedwater inlet of the economizer is connected to the feedwater outlet of the feedwater regeneration system, and the feedwater outlet of the economizer is connected to the feedwater inlet of the water-cooled wall. The steam outlet of the water-cooled wall is connected to the steam inlet of the low-temperature superheater, and the steam outlet of the low-temperature superheater is connected to the steam inlet of the high-temperature superheater. Feedwater flows through the economizer and then into the water-cooled wall, where it vaporizes into steam. The steam then flows sequentially through the low-temperature superheater and the high-temperature superheater, ultimately becoming the main steam. The structure of the second coal-fired boiler 12 is similar and will not be described in detail here.

[0091] Steam turbines are used to convert the internal energy of steam into mechanical energy. The first steam turbine includes a first high-pressure cylinder 211, a first intermediate-pressure cylinder 212, and a first low-pressure cylinder 213. Similarly, the second steam turbine includes a second high-pressure cylinder 231, a second intermediate-pressure cylinder 232, and a second low-pressure cylinder 233; the third steam turbine includes a third high-pressure cylinder 221, a third intermediate-pressure cylinder 222, and a third low-pressure cylinder 223.

[0092] For example, the thermal system 100 includes a pipeline connection system 3, which includes a first connecting pipeline 321, a second connecting pipeline 322, a third connecting pipeline 323, and a fourth connecting pipeline 324. The first connecting pipeline 321 connects the first boiler body 111 and the first steam turbine unit 21. The second connecting pipeline 322 connects the first boiler body 111 and the third steam turbine unit 22. The third connecting pipeline 323 connects the second boiler body 121 and the third steam turbine unit 22. The fourth connecting pipeline 324 connects the second boiler body 121 and the second steam turbine unit 23. The first connecting pipeline 321 is equipped with a first regulating valve 331. The second connecting pipeline 322 is equipped with a second regulating valve. The third connecting pipeline 323 is equipped with a third regulating valve 333. The fourth connecting pipeline 324 is equipped with a fourth regulating valve 334.

[0093] The first coal-fired boiler 11 is connected to the first steam turbine unit 21 and the second steam turbine unit 23 by pipelines. For example, the main steam outlet of the first coal-fired boiler 11 is connected to the first header pipe 311, the first header pipe 311 is connected to the steam inlet of the first steam turbine unit 21 through the first connecting pipe 321, the main steam outlet of the first coal-fired boiler 11 is connected to the first header pipe 311, and the first header pipe 311 is connected to the steam inlet of the third steam turbine unit 22 through the second connecting pipe 322. As a design feature, the first header pipe 311 is equipped with a steam inlet regulating valve and a desuperheating and pressure reducing valve 352, and the first connecting pipe 321 and the second connecting pipe 322 are also equipped with steam inlet regulating valves and desuperheating and pressure reducing valves 352. Similarly, the second coal-fired boiler 12 is connected to the second turbine unit 23 and the third turbine unit 22 via pipelines. For example, the main steam outlet of the second coal-fired boiler 12 is connected to the second header pipe 312, the second header pipe 312 is connected to the steam inlet of the third turbine unit 22 via the third connecting pipe 323, the main steam outlet of the second coal-fired boiler 12 is connected to the second header pipe 312, and the second header pipe 312 is connected to the steam inlet of the second turbine unit 23 via the fourth connecting pipe 324. As a design feature, the second header pipe 312 is equipped with a steam inlet regulating valve and a desuperheating and pressure reducing valve 352, and the third connecting pipe 323 and the fourth connecting pipe 324 are also equipped with steam inlet regulating valves and desuperheating and pressure reducing valves 352.

[0094] The thermal system 100 for deep peak shaving provided in this application embodiment can switch between multiple one-boiler-one-turbine modes and one-boiler-two-turbine modes. During periods of high load electricity consumption, all boilers and all steam turbines can operate at full power. During periods of low load electricity consumption, the power plant output can be reduced by "shutting down the boiler without stopping the turbine", thereby greatly improving the system's deep peak shaving capability.

[0095] According to some embodiments of the present invention, a first coal-fired boiler 11 includes a first reheater 112, a second coal-fired boiler 12 includes a second reheater 122, a first steam turbine is connected to the first reheater 112 via a first return pipe 341, and a deep peak-shaving thermal system 100 further includes a mixing tank 344, a second steam turbine is connected to the mixing tank 344 via a second return pipe 342, and a third steam turbine is connected to the mixing tank 344 via a third return pipe 343. The mixing tank 344 is connected to the second reheater 122 via a connecting main pipe. The second return pipe 342 is provided with an intake regulating valve 351, a desuperheating and pressure reducing valve 352, and a mechanical steam recompression system 353. The desuperheating and pressure reducing valve 352 is closer to the mixing tank 344 than the mechanical steam recompression system 353. By connecting the second return pipe 342 and the third return pipe 343 through the mixing tank 344, the danger caused by steam collisions at different temperatures and pressures can be prevented.

[0096] It is understood that the system provided in this application embodiment can be extended to a more complex system, such as a three-furnace-three-machine, three-furnace-four-machine, four-furnace-four-machine, etc. The operating modes are different, but the execution logic is similar. For the sake of simplicity, it will not be described in detail here.

[0097] When the total power load meets the first preset condition, the system is switched to the first operating mode, the second regulating valve and the third regulating valve 333 are opened, and the first regulating valve 331 and the fourth regulating valve 334 are closed. When the total power load meets the second preset condition, the system is switched to the second operating mode, the first regulating valve 331 and the fourth regulating valve 334 are opened, and the second regulating valve and the third regulating valve 333 are closed. When the total power load meets the third preset condition, the system is switched to the third operating mode, the first regulating valve 331, the third regulating valve 333 and the fourth regulating valve 334 are opened, and the second regulating valve is closed. When the total power load meets the fourth preset condition, the system will be switched to the fourth operating mode, and the first regulating valve 331, the second regulating valve, the third regulating valve 333 and the fourth regulating valve 334 will be opened.

[0098] The thermal system 100 for deep peak shaving according to an embodiment of the present invention can flexibly adapt to a wide range of power peak shaving demands by dynamically switching the pipeline connection mode between the coal-fired boiler and the steam turbine unit in a one-boiler-two-turbine operation system. By optimizing the operating mode and load matching, it ensures that the boiler always operates within a relatively efficient and stable load range, thereby improving the economy, reliability, and peak shaving depth of the entire system.

[0099] According to some embodiments of the present invention, a control device is also included, which includes a processor 41, a memory 42, and a computer program stored in the memory 42 and executable on the processor 41. When the processor 41 executes the computer program, it causes the thermal system 100 to implement the thermal system 100 control method for deep peak shaving according to an embodiment of the first aspect of the present invention.

[0100] In the description of this invention, it should be understood that the terms "center," "longitudinal," "lateral," "length," "width," "thickness," "upper," "lower," "front," "rear," "left," "right," "vertical," "horizontal," "top," "bottom," "inner," "outer," "clockwise," "counterclockwise," "axial," "radial," and "circumferential" indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are used only for the convenience of describing this invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on this invention.

[0101] In the description of this invention, "first feature" and "second feature" may include one or more of the features.

[0102] In the description of this invention, "a plurality of" means two or more.

[0103] In the description of this invention, the first feature being "above" or "below" the second feature may include the first and second features being in direct contact, or it may include the first and second features not being in direct contact but being in contact through another feature between them.

[0104] In the description of this invention, the terms "above," "over," and "on top" for the first feature and the second feature include the first feature being directly above or diagonally above the second feature, or simply indicating that the first feature is at a higher horizontal level than the second feature.

[0105] In the description of this specification, the references to terms such as "one embodiment," "some embodiments," "illustrative embodiment," "example," "specific example," or "some examples," etc., indicate that a specific feature, structure, material, or characteristic described in connection with that embodiment or example is included in at least one embodiment or example of the invention. In this specification, the illustrative expressions of the above terms do not necessarily refer to the same embodiment or example. Furthermore, the specific features, structures, materials, or characteristics described may be combined in any suitable manner in one or more embodiments or examples.

[0106] Although embodiments of the invention have been shown and described, those skilled in the art will understand that various changes, modifications, substitutions and alterations can be made to these embodiments without departing from the principles and spirit of the invention, the scope of which is defined by the claims and their equivalents.

Claims

1. A control method for a thermal system for deep peak shaving, characterized in that, The thermal system includes two coal-fired boilers and three steam turbine units. The two coal-fired boilers are a first coal-fired boiler and a second coal-fired boiler. The three steam turbine units are a first steam turbine unit, a second steam turbine unit, and a third steam turbine unit. The first coal-fired boiler is connected to the first steam turbine unit and the third steam turbine unit by a pipeline. The pipelines are not connected by default. The control method includes: Determine the total electricity load indicated by the current peak-shaving demand; When the total power load meets the first preset condition, the system is switched to the first operating mode. In the first operating mode, the pipeline between the first coal-fired boiler and the third steam turbine unit is connected, and the pipeline between the second coal-fired boiler and the third steam turbine unit is also connected. When the total power load meets the second preset condition, the system is switched to the second operating mode. In the second operating mode, the pipeline between the first coal-fired boiler and the first steam turbine unit is connected, and the pipeline between the second coal-fired boiler and the second steam turbine unit is also connected. When the total power load meets the third preset condition, the system is switched to the third operating mode. In the third operating mode, the pipeline between the first coal-fired boiler and the first steam turbine unit is connected, and the pipeline between the second coal-fired boiler and the second steam turbine unit and the third steam turbine unit is connected. When the total power load meets the fourth preset condition, the system is switched to the fourth operating mode. In the fourth operating mode, the pipeline between the first coal-fired boiler and the first turbine unit and the third turbine unit is connected, and the pipeline between the second coal-fired boiler and the second turbine unit and the third turbine unit is connected. The power load requirements corresponding to the first preset condition, the second preset condition, the third preset condition, and the fourth preset condition increase sequentially. The first rated power of the first turbine unit is configured based on the first minimum stable combustion load of the first coal-fired boiler. The second rated power of the second turbine unit is configured based on the second minimum stable combustion load of the second coal-fired boiler. The third rated power of the third turbine unit is configured based on the following information: the first rated power, the second rated power, the first rated evaporation capacity of the first coal-fired boiler, and the second rated evaporation capacity of the second coal-fired boiler.

2. The thermal system control method for deep peak shaving according to claim 1, characterized in that, The first preset condition includes: the total power load is less than or equal to a first threshold, and the switching duration is greater than or equal to a first duration, wherein the switching duration is the time interval between the current moment and the moment of the last switching of the operating mode; The second preset condition includes: the total power load is greater than the third threshold and less than or equal to the fourth threshold, and the switching duration is greater than or equal to the first duration; The third preset condition includes: the total power load is greater than the fifth threshold and less than or equal to the sixth threshold, and the switching duration is greater than or equal to the first duration; The fourth preset condition includes: the total power load is greater than the seventh threshold, and the switching duration is greater than or equal to the first duration; The values ​​of the first threshold, the third threshold, the fourth threshold, the fifth threshold, the sixth threshold, and the seventh threshold increase sequentially; The method further includes: The current operating mode will remain unchanged if the total electrical load meets any of the following conditions: The total power load is greater than the first threshold and less than or equal to the third threshold, the total power load is greater than the fourth threshold and less than or equal to the fifth threshold, and the total power load is greater than the sixth threshold and less than or equal to the seventh threshold.

3. The thermal system control method for deep peak shaving according to claim 1 or 2, characterized in that, Also includes: With the goal of minimizing the total coal consumption of the first and second coal-fired boilers, a load allocation scheme is determined using the quantum particle swarm optimization algorithm while satisfying constraints. The constraints are related to the current operating mode and are used to ensure that the total power generation of the system meets the total power load requirements while meeting safety requirements. Adjust the main steam pressure of the first and second coal-fired boilers, as well as the output power of the currently connected turbine unit, according to the load distribution scheme.

4. The thermal system control method for deep peak shaving according to claim 3, characterized in that, The constraints include: The total output power of the turbine units currently connected to the first and second coal-fired boilers meets the total power load demand. The sum of the steam output of the first and second coal-fired boilers is equal to the amount of steam required to reach the output power of the turbine units that are turned on. The steam output of each of the first and second coal-fired boilers and the output power of the connected turbine units meet the constraints of the current operating mode. The steam output of the first coal-fired boiler is between the minimum steam output and the rated evaporation capacity corresponding to the first coal-fired boiler, and the steam output of the second coal-fired boiler is between the minimum steam output and the rated evaporation capacity corresponding to the second coal-fired boiler.

5. The thermal system control method for deep peak shaving according to claim 3, characterized in that, The constraints also include: the load change rate of the first coal-fired boiler and the second coal-fired boiler is less than or equal to the eighth threshold, the ramp rate of the connected steam turbine unit is less than or equal to the ninth threshold, and the steam header pressure corresponding to the first coal-fired boiler and the second coal-fired boiler is less than or equal to the tenth threshold.

6. The thermal system control method for deep peak shaving according to claim 1 or 2, characterized in that, Before switching the system to any operating mode, the method further includes: Based on historical load data, power grid dispatching plans, and weather forecasts, predict load change curves; Based on the load change curve and the first preset condition, the second preset condition, the third preset condition, and the fourth preset condition, determine the operating mode to be switched and the expected mode switching time. Before the specified mode switching time point, the first coal-fired boiler and the second coal-fired boiler are controlled to enter a first pre-switching state, and / or one or more of the first turbine unit, the second turbine unit, and the third turbine unit are controlled to enter a second pre-switching state. The first pre-switching state and the second pre-switching state are associated with the mode to be switched. The first pre-switching state is a transitional state between the current operating mode and the operating mode to be switched for the first coal-fired boiler and the second coal-fired boiler. The second pre-switching state is a transitional state between the current operating mode and the operating mode to be switched for the first turbine unit, the second turbine unit, and the third turbine unit.

7. The thermal system control method for deep peak shaving according to claim 6, characterized in that, The control of the first coal-fired boiler and the second coal-fired boiler to enter the first pre-switching state includes: Slowly adjust the combustion and steam parameters of the first and second coal-fired boilers to match the outlet steam state with the state required for the operating mode to be switched.

8. The thermal system control method for deep peak shaving according to claim 6, characterized in that, The control of one or more of the first turbine unit, the second turbine unit, and the third turbine unit to enter the second pre-switching state includes: The equipment to be started in the first, second, and third turbine units is warmed up at low speed and evacuated, and the main pipe pressure is gradually adjusted to the range required for the operating mode to be switched; or, The equipment to be shut down in the first turbine unit, the second turbine unit, and the third turbine unit will be gradually transferred to a new load.

9. A thermal system for deep peak shaving, characterized in that, The thermal system includes two coal-fired boilers and three turbine units: a first coal-fired boiler, a second coal-fired boiler, a first turbine unit, a second turbine unit, and a third turbine unit. The first coal-fired boiler is connected to the first turbine unit and the third turbine unit by pipeline, and the second coal-fired boiler is connected to the second turbine unit and the third turbine unit by pipeline. The pipelines are not connected by default. The thermal system can operate the method as described in any one of claims 1 to 8.

10. The thermal system for deep peak shaving according to claim 9, characterized in that, It also includes a control device, which includes a processor, a memory, and a computer program stored in the memory and executable on the processor. When the processor executes the computer program, it causes the thermal system to implement the thermal system control method for deep peak shaving as described in any one of claims 1-8.

Images