Method for coordinating control of a solar thermal power plant, system for coordinating control of a solar thermal power plant and molten salt energy storage solar thermal power plant

Abstract

This invention relates to a coordinated control method, a coordinated control system, and a molten salt energy storage solar thermal power plant. The coordinated control method includes: determining the operating mode of the molten salt energy storage solar thermal power plant; when the molten salt energy storage solar thermal power plant is in heat storage mode, selecting the turbine's power generation mode based on the preset heat storage capacity, remaining heat storage duration, and current parameters of the hot salt tank; when the molten salt energy storage solar thermal power plant is in heat release mode, engaging the turbine under pressure control; obtaining the target flow rate at the hot salt tank outlet based on the preset heat release rate and current parameters of the hot salt tank; using closed-loop feedback control of the hot salt pump output parameters based on the target flow rate and the actual flow rate at the hot salt tank outlet; and when the molten salt energy storage solar thermal power plant is in power generation mode, engaging the turbine under power control, setting the preset power generation capacity of the turbine, and using closed-loop feedback control of the hot salt pump output parameters based on the main steam pressure setpoint. This invention can effectively improve the safety and stability of the molten salt energy storage solar thermal power plant operation.

Description

Technical Field

[0001] This invention relates to the field of concentrated solar power (CSP) technology, and more specifically, to a coordinated control method for a CSP plant, a coordinated control system for a CSP plant, and a molten salt energy storage CSP plant. Background Technology

[0002] Decoupled molten salt energy storage solar thermal power generation technology is complex, encompassing a thermal collection system, a thermal storage system, and a power generation system. Its key feature is the decoupling of the thermal collection and storage system from the power generation system, ensuring they do not interfere with each other and eliminating the impact of solar irradiance fluctuations on the stability of turbine output.

[0003] This type of power plant has widely distributed equipment, numerous control parameters, and high requirements for automation control. Its thermal system exhibits large inertia, large delay, and nonlinear characteristics. From the solar thermal collector focusing solar heat to the temperature change of the molten salt output by the collector, and then to the superheated qualified steam generated by the steam generator in the power generation system to drive the turbine to generate electricity, the entire process involves energy exchange through multiple media, resulting in extremely high system inertia.

[0004] The mutual constraints and interdependence between the heat collection system, heat storage system and power generation system of a decoupled molten salt energy storage solar thermal power plant necessitate a coordinated control system to coordinate the operation parameters of each system in order to ensure the safe and stable operation of the unit. Summary of the Invention

[0005] The technical problem to be solved by the present invention is to provide a coordinated control method for a solar thermal power plant, a coordinated control system for a solar thermal power plant, and a molten salt energy storage solar thermal power plant, in response to the above-mentioned defects of the prior art.

[0006] The technical solution adopted by this invention to solve its technical problem is: constructing a coordinated control method for a solar thermal power plant, comprising: The operating modes of the molten salt energy storage solar thermal power plant are determined; the operating modes include thermal storage mode, thermal release mode, and power generation mode. When the molten salt energy storage solar thermal power plant is in the thermal storage mode, the power generation mode of the steam turbine is selected according to the preset thermal storage capacity, the remaining thermal storage duration, and the current parameters of the hot salt tank; the power generation mode includes variable load power generation mode and minimum load power generation mode; When the power generation mode is the variable load power generation mode, the current power generation of the steam turbine is determined according to the preset thermal storage capacity, the remaining thermal storage duration, and the current parameters of the hot salt tank; When the power generation mode is the minimum load power generation mode, the current power generation of the steam turbine is determined according to the minimum load ratio of the rated power generation of the steam turbine. When the molten salt energy storage solar thermal power plant is in the heat release mode, the steam turbine is put into pressure control; the target flow rate of the hot salt tank outlet is obtained according to the preset heat release rate and the current parameters of the hot salt tank; the output parameters of the hot salt pump are controlled by closed-loop feedback according to the target flow rate of the hot salt tank outlet and the actual flow rate of the hot salt tank outlet. When the molten salt energy storage solar thermal power plant is in the power generation mode, the steam turbine is put into power control, the preset power generation power of the steam turbine is set, and the output parameters of the hot salt pump are controlled by closed-loop feedback according to the main steam pressure setpoint.

[0007] Furthermore, the step of selecting the turbine's power generation mode based on the preset thermal storage capacity, remaining thermal storage duration, and current parameters of the thermal salt tank includes: The available power generation capacity of the steam turbine is obtained based on the preset thermal storage capacity, the current parameters of the hot salt tank, and the remaining thermal storage duration. The minimum power generation capacity of the steam turbine is obtained based on the rated power generation capacity of the steam turbine, the minimum load ratio, and the remaining heat storage time. The available generating capacity is compared with the minimum generating capacity; when the available generating capacity is less than the minimum generating capacity, the minimum load generating mode is adopted; when the available generating capacity is greater than or equal to the minimum generating capacity, the variable load generating mode is adopted.

[0008] Further, obtaining the available power generation capacity of the steam turbine based on the preset thermal storage capacity, the current parameters of the hot salt tank, and the remaining thermal storage duration includes: The remaining thermal storage capacity is obtained based on the current parameters of the hot salt tank and the remaining thermal storage duration. The current thermal storage capacity is obtained based on the current parameters of the hot salt tank. The available power generation capacity of the steam turbine is obtained based on the remaining thermal storage capacity, the current thermal storage capacity, and the preset thermal storage capacity.

[0009] Furthermore, the current parameters of the hot salt tank include the molten salt temperature, the current liquid level, the inlet flow rate, the molten salt heat capacity, and the dimensions of the hot salt tank. The remaining thermal storage capacity is obtained according to Formula 1; Formula 1 in, For the remaining thermal storage capacity, This refers to the inlet flow rate of the hot salt tank. For the remaining thermal storage time, For the molten salt heat capacity of the hot salt container, This refers to the molten salt temperature in the hot salt tank. The current thermal storage capacity is obtained according to Formula 2; Formula 2 in, For the current thermal storage capacity, This is the current liquid level in the hot salt tank. The cross-sectional area of ​​the hot salt container. The density of molten salt, For the molten salt heat capacity of the hot salt container, This refers to the molten salt temperature in the hot salt tank. The power generation capacity is obtained according to Formula 3; Formula 3 in, This refers to the available power generation capacity of the steam turbine. This represents the thermal storage capacity for the remaining thermal storage period. For the current thermal storage capacity, The preset thermal storage capacity; The minimum power generation capacity is obtained according to Formula 4; Formula 4 in, This represents the minimum generating capacity of the steam turbine. The rated power output of the steam turbine; This refers to the minimum load ratio; This represents the remaining thermal storage time.

[0010] Furthermore, when the power generation mode is a variable load power generation mode, the current power generation capacity of the steam turbine is obtained according to Formula 5; Formula 5 in, This represents the current generating capacity of the turbine in variable load power generation mode. The available power generation capacity of the steam turbine. For the remaining thermal storage duration; and / or When the power generation mode is the minimum load power generation mode, the current power generation of the steam turbine is obtained according to Formula 6; Formula Six in, This represents the current generating capacity of the turbine in the lowest load power generation mode. The rated power output of the steam turbine; This refers to the minimum load ratio.

[0011] Furthermore, the minimum load ratio is greater than or equal to 10% and less than or equal to 20%.

[0012] Furthermore, the target flow rate at the outlet of the hot salt tank is obtained according to Formula 7; Formula 7 in, Where A is the target flow rate at the outlet of the hot salt tank, and A is the preset heat release rate. For the molten salt heat capacity of the hot salt container, This refers to the temperature at which the salt melts in the hot salt tank.

[0013] Furthermore, the closed-loop feedback control of the hot salt pump output parameters based on the main steam pressure setpoint includes: Based on the given value of the main steam pressure, the output parameters of the hot salt pump are adjusted using a cascade PID controller; wherein, the main PID controller is the main steam pressure value, and the secondary PID controller is the hot salt tank outlet flow rate.

[0014] A coordinated control system for a concentrated solar power (CSP) plant is constructed, comprising a processor and a memory storing a computer program, wherein the processor, when executing the computer program, implements the coordinated control method for the CSP plant described in any of the preceding claims.

[0015] Construct a molten salt energy storage solar thermal power plant, including the solar thermal power plant coordination and control system described in any of the preceding claims.

[0016] The technical solution constructed by implementing the present invention has at least the following beneficial effects: The solar thermal power plant coordinated control method proposed in this invention adopts different control schemes based on different operating modes to achieve coordinated control of the heat collection system, heat storage system, and power generation system. This ensures that the heat storage system and the power generation system are in a stable operating state under different modes, effectively improving the safety and stability of the molten salt energy storage solar thermal power plant. Attached Figure Description

[0017] The present invention will be further described below with reference to the accompanying drawings and embodiments. In the accompanying drawings: Figure 1 This is a schematic diagram of the structure of a molten salt energy storage solar thermal power plant according to one embodiment of the present invention; Figure 2 This is a flowchart of a solar thermal power plant coordinated control method according to an embodiment of the present invention; Figure 3 yes Figure 2 The diagram shows the control logic of the coordinated control method for a solar thermal power plant when the molten salt energy storage solar thermal power plant is in thermal storage mode. Figure 4 yes Figure 2 The diagram shows the control logic of the coordinated control method for a solar thermal power plant when the molten salt energy storage solar thermal power plant is in heat release mode. Figure 5 yes Figure 2 The diagram shows the control logic of the coordinated control method for a solar thermal power plant when the molten salt energy storage solar thermal power plant is in power generation mode. Detailed Implementation

[0018] To provide a clearer understanding of the technical features, objectives, and effects of the present invention, specific embodiments are now described in detail with reference to the accompanying drawings. Many specific details are set forth in the following description to provide a thorough understanding of the invention. However, the invention can be practiced in many ways different from those described herein, and those skilled in the art can make similar modifications without departing from the spirit of the invention. Therefore, the invention is not limited to the specific embodiments disclosed below.

[0019] In the description of this invention, it should be understood that the terms "longitudinal", "lateral", "up", "down", "top", "bottom", "inner", "outer", etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings or the orientation or positional relationship commonly used when the product of this invention is in use. They are 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.

[0020] Furthermore, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of indicated technical features. Thus, a feature defined as "first" or "second" may explicitly or implicitly include at least one of that feature. In the description of this invention, "a plurality of" means at least two, such as two, three, etc., unless otherwise explicitly specified.

[0021] In this invention, unless otherwise explicitly specified and limited, the terms "installation," "connection," "linking," and "fixing," etc., should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral part; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; they can refer to the internal communication of two components or the interaction between two components, unless otherwise explicitly limited. Those skilled in the art can understand the specific meaning of the above terms in this invention according to the specific circumstances.

[0022] In this invention, unless otherwise explicitly specified and limited, "above" or "below" the second feature can mean that the first feature is in direct contact with the second feature, or that the first feature is in indirect contact with the second feature through an intermediate medium. Furthermore, "above" the second feature can mean that the first feature is directly above or diagonally above the second feature, or simply that the first feature is at a higher horizontal level than the second feature. "Below" the second feature can mean that the first feature is directly below or diagonally below the second feature, or simply that the first feature is at a lower horizontal level than the second feature.

[0023] like Figure 2As shown, the present invention constructs a coordinated control method for a solar thermal power plant, which can be used to coordinate and control various systems of a molten salt energy storage solar thermal power plant.

[0024] like Figure 1 As shown, the molten salt energy storage solar thermal power plant may include a decoupled solar collector system 10, a solar storage system 20, a power generation system 30, and a solar thermal power plant coordination control system. The solar collector system 10 may include at least one collector connected to the hot salt tank 21 and the cold salt tank 22 in the solar storage system 20 to form a molten salt loop, enabling heat exchange through molten salt circulation. A hot salt pump 23 is installed at the outlet of the hot salt tank 21 to pump the molten salt from the hot salt tank 21 to the power generation system 30.

[0025] The power generation system 30 may include a power generation module 31 and a heat exchange module 32. The power generation module 31 may include a steam turbine 311 and a generator 312. The heat exchange module 32 is disposed between the power generation module 31 and the thermal storage system 20 to achieve heat exchange between the two, thereby enabling the power generation module 31 to generate electricity. The heat exchange module 32 may include at least one heat exchanger, which can form heat exchange loops with both the power generation module 31 and the thermal storage system 20 to achieve heat exchange between them.

[0026] The solar thermal power plant's coordinated control system is communicatively connected to the other systems. It may include a processor and a memory storing computer programs to implement the coordinated control method for the solar thermal power plant.

[0027] like Figure 2 As shown, the coordinated control method for this solar thermal power plant may include the following steps.

[0028] Determine the operating mode of the molten salt energy storage solar thermal power plant.

[0029] The operating modes can include thermal storage mode, heat release mode, and power generation mode. When the molten salt energy storage solar thermal power plant is in thermal storage mode, its primary objective is thermal storage, and the power generation system 30 operates in conjunction with the thermal storage system 20. In this mode, the heat collection system 10 can be in an active or inactive state, without specific limitations. When the molten salt energy storage solar thermal power plant is in heat release mode, its primary objective is heat release, and the power generation modules 31 of both the thermal storage system 20 and the power generation system 30 operate in conjunction with the heat exchange modules 32 of the power generation system 30. In this mode, the heat collection system 10 can be in an active or inactive state, without specific limitations. When the molten salt energy storage solar thermal power plant is in power generation mode, its primary objective is power generation, and the heat exchange modules 32 of both the thermal storage system 20 and the power generation system 30 operate in conjunction with the power generation module 31. In this mode, the heat collection system 10 can be in an active or inactive state, without specific limitations.

[0030] When the molten salt energy storage solar thermal power plant is in thermal storage mode, the power generation mode of turbine 311 is selected based on the preset thermal storage capacity, remaining thermal storage duration, and current parameters of the hot salt tank.

[0031] The power generation modes of the steam turbine 311 may include variable load power generation mode and minimum load power generation mode.

[0032] When the turbine 311 operates in variable load power generation mode, its current power generation capacity is determined based on the preset thermal storage capacity, remaining thermal storage duration, and current parameters of the hot salt tank. At this time, the power generation capacity of the turbine 311 changes in real time with the changes in the remaining thermal storage duration and the current parameters of the hot salt tank.

[0033] When the turbine is operating in minimum load mode, the current power output of the turbine is determined based on the minimum load ratio of the turbine's rated power output. At this time, the turbine's power output is a fixed value.

[0034] When the molten salt energy storage solar thermal power plant is in heat release mode, the turbine 311 is put into pressure control. The target flow rate at the outlet of the hot salt tank is obtained based on the preset heat release rate and the current parameters of the hot salt tank. The output parameters of the hot salt pump 23 are controlled by closed-loop feedback based on the target flow rate and the actual flow rate at the outlet of the hot salt tank.

[0035] When the molten salt energy storage solar thermal power plant is in power generation mode, the steam turbine 311 is put into power control, the preset power generation power of the steam turbine 311 is set, and the output parameters of the hot salt pump 23 are controlled by closed-loop feedback according to the main steam pressure setpoint.

[0036] This invention, by further determining the power generation mode of the steam turbine 311 based on various parameters under thermal storage mode, enables flexible energy allocation under thermal storage mode. When thermal storage is sufficient, the steam turbine 311 can generate electricity flexibly; when thermal storage is insufficient, priority is given to thermal storage to ensure the safe and stable operation of the unit and avoid the risk of shutdown. In this way, the purpose of thermal storage can be achieved, and flexible utilization of energy resources can be realized while ensuring the safe and stable operation of the unit.

[0037] This invention achieves stable heat output from the hot salt tank 21 by using closed-loop feedback control of the output parameters of the hot salt pump 23 based on the target flow rate at the outlet of the hot salt tank in the heat release mode, thereby ensuring the stability of the heat release rate.

[0038] This invention sets the preset power generation capacity of the steam turbine 311 in power generation mode and controls the output parameters of the hot salt pump 23 through closed-loop feedback based on the main steam pressure setpoint of the steam turbine 311. This enables the hot salt pump 23 to automatically match the power generation load demand of the steam turbine 311, effectively improving the operational stability and safety in power generation mode.

[0039] It should be noted that the operators can input the preset thermal storage capacity and preset thermal storage duration of the hot salt tank 21 in thermal storage mode, the preset heat release rate of the hot salt tank 21 in heat release mode, the preset power generation power of the steam turbine 311 in power generation mode, and the set value of the main steam pressure into the coordinated control system of the solar thermal power plant.

[0040] The remaining thermal storage time can be obtained by subtracting the preset thermal storage time from the duration of operation of the thermal storage mode.

[0041] It should be noted that the current parameters of the hot salt tank may include the liquid level, size, internal molten salt density, internal molten salt heat capacity, internal molten salt temperature, molten salt flow rate at the inlet, and molten salt flow rate at the outlet of the hot salt tank 21.

[0042] It should be noted that putting the steam turbine 311 into pressure control and power control can be achieved through the steam turbine 311's DEH (Digital Electro-Hydraulic Control System), which is existing technology and will not be discussed further here.

[0043] like Figure 3 As shown, in some embodiments, when the molten salt energy storage solar thermal power plant is in thermal storage mode, the power generation mode of the steam turbine 311 is selected according to the preset thermal storage capacity, the remaining thermal storage duration, and the current parameters of the hot salt tank. Specifically, the following steps may be included.

[0044] The available power generation capacity of turbine 311 is obtained based on the preset thermal storage capacity, the current parameters of the hot salt tank, and the remaining thermal storage time.

[0045] The minimum power generation capacity of turbine 311 is obtained based on the turbine's rated power generation capacity, minimum load ratio, and remaining heat storage time.

[0046] Compare the available power generation capacity with the minimum power generation capacity. When the available power generation capacity is less than the minimum power generation capacity, the minimum load power generation mode is used. When the available power generation capacity is greater than or equal to the minimum power generation capacity, the variable load power generation mode is used.

[0047] This invention achieves synergistic effects between thermal energy storage and power generation by setting two different power generation modes for the turbine 311 based on its minimum power generation capacity. Simultaneously, it avoids the thermal energy storage mode being affected by the heat collection system 10, allowing the power generation system 30 to be independently adjusted according to the thermal energy storage capacity of the thermal energy storage system 20. Thus, when thermal energy storage is sufficient, a variable load power generation mode can be used to dynamically adjust the power generation operation of the power generation system 30 based on the thermal energy storage situation, achieving efficient utilization of thermal energy storage resources. When thermal energy storage is insufficient, a minimum load power generation mode can be used to ensure the safe and stable operation of the unit, avoiding equipment downtime and damage. The two modes work together to improve the flexibility and economy of the molten salt energy storage solar thermal power plant, and also ensure the long-term safe and stable operation of the power plant.

[0048] Specifically, the available power generation capacity can be obtained through the following steps.

[0049] The remaining thermal storage capacity is obtained based on the current parameters of the hot salt tank and the remaining thermal storage time.

[0050] The current thermal storage capacity is obtained based on the current parameters of the hot salt tank.

[0051] Based on the remaining thermal storage capacity, the current thermal storage capacity, and the preset thermal storage capacity, the available power generation capacity of turbine 311 is obtained.

[0052] Furthermore, the remaining thermal storage capacity can be obtained using Formula 1.

[0053] Formula 1 in, For the remaining thermal storage capacity, This refers to the inlet flow rate of the hot salt tank. For the remaining thermal storage time, For the molten salt heat capacity of the hot salt container, This refers to the temperature at which the salt melts in the hot salt tank.

[0054] The current thermal storage capacity can be obtained using Formula 2.

[0055] Formula 2 in, For the current thermal storage capacity, The current liquid level in hot salt tank 21 The cross-sectional area of ​​the hot salt container 21 is... The density of molten salt, For the molten salt heat capacity of hot salt container 21, The temperature of the molten salt in the hot salt tank 21.

[0056] The power generation capacity can be obtained using Formula 3.

[0057] Formula 3 in, The available power generation capacity of turbine 311. The remaining heat storage capacity of the hot salt tank 21 during its remaining heat storage time. This represents the current thermal storage capacity of the hot salt tank 21. The preset heat storage capacity of the hot salt tank 21.

[0058] The minimum power generation capacity can be obtained using Formula 4.

[0059] Formula 4 in, This represents the minimum power generation capacity of turbine 311; The rated power generation capacity of the steam turbine 311; This represents the minimum load percentage. This represents the remaining thermal storage time.

[0060] In some embodiments, when the power generation mode of the steam turbine 311 in the thermal storage mode is selected as the variable load power generation mode, the current power generation of the steam turbine 311 can be obtained by formula five.

[0061] Formula 5 in, This represents the current generating capacity of turbine 311 in variable load power generation mode. The available power generation capacity of turbine 311. This represents the remaining thermal storage time.

[0062] In some embodiments, when the power generation mode of the steam turbine 311 is selected as the minimum load power generation mode in the thermal storage mode, the current power generation of the steam turbine 311 can be obtained using Formula Six.

[0063] Formula Six in, This represents the current generating capacity of turbine 311 in the lowest load power generation mode. This is the rated power output of turbine 311; This represents the minimum load percentage.

[0064] It should be noted that this minimum load ratio can be flexibly set based on the performance parameters of the equipment in the power generation module 31 and the heat exchange module 32.

[0065] For example, in some embodiments, the minimum load percentage may be greater than or equal to 10% and less than or equal to 20%, specifically 11%, 12%, 13%, 14%, 15%, 16%, 17%, 18%, 19%, or any other value within that range.

[0066] like Figure 4As shown, in some embodiments, when the molten salt energy storage solar thermal power plant is in heat release mode, the output parameters of the hot salt pump 23 are controlled by closed-loop feedback based on the target flow rate at the outlet of the hot salt tank 21 and the actual flow rate at the outlet of the hot salt tank 21. Specifically, a PID controller can be used to implement this control.

[0067] Specifically, the target outlet flow rate of the hot salt tank 21 can be obtained using Formula 7.

[0068] Formula 7 in, Let A be the target flow rate at the outlet of the hot salt tank, and let A be the preset heat release rate. For the molten salt heat capacity of the hot salt container, This refers to the temperature at which the salt melts in the hot salt tank.

[0069] In other embodiments, the output parameters of the hot salt pump 23 can be controlled by closed-loop feedback based on the target outlet flow rate of the hot salt tank 21 and the actual outlet flow rate of the hot salt tank 21. Other control methods such as PI control, cascade PID regulation, and feedforward feedback composite control can also be used.

[0070] like Figure 5 As shown, in some embodiments, when the molten salt energy storage solar thermal power plant is in power generation mode, the output parameters of the hot salt pump are controlled by closed-loop feedback based on the main steam pressure setpoint. Specifically, this includes adjusting the output parameters of the hot salt pump 23 using a cascaded PID controller based on the main steam pressure setpoint. The primary PID controller is the main steam pressure value, and the secondary PID controller is the outlet flow rate of the hot salt tank 21.

[0071] This invention improves the anti-interference capability, dynamic response speed and regulation accuracy of the molten salt energy storage solar thermal power plant in power generation mode by using cascade PID regulation to automatically control the output of the hot salt pump 23, effectively reducing the main steam pressure fluctuation and ensuring the safe and stable operation of the steam turbine 311.

[0072] In some other embodiments, the automatic control of the thermosalt pump 23 in power generation mode can also be achieved by other methods such as PID regulation and feedforward feedback composite control.

[0073] In some embodiments, the output parameters of the aforementioned hot salt pump 23 can be specifically understood as the frequency of the inverter of the hot salt pump 23.

[0074] The present invention also constructs a coordinated control system for a concentrated solar power (CSP) plant, which may include a processor and a memory storing a computer program. When the processor executes the computer program, it implements the CSP plant coordinated control method of any of the foregoing embodiments.

[0075] like Figure 1As shown, the present invention also constructs a molten salt energy storage solar thermal power plant, which may include a decoupled heat collection system 10, a heat storage system 20, a power generation system 30, and a solar thermal power plant coordination control system in any of the foregoing embodiments.

[0076] It should be noted that the thermal collection system 10, the thermal storage system 20, and the power generation system 30 can all be implemented using existing technologies.

[0077] For example, the solar collector system 10 may include at least one of existing solar collectors such as a tower-type central receiver 11, a parabolic solar collector 12, or a linear Nefertory solar collector 13.

[0078] For example, the thermal storage system 20 may include an existing hot salt tank 21, a cold salt tank 22, and a hot salt pump 23, which is located at the outlet of the hot salt tank 21.

[0079] For example, the power generation system 30 may include a power generation module 31 and a heat exchange module 32. The power generation module 31 may include an existing steam turbine 311 and a generator 312. The heat exchange module 32 may include an existing superheater 321, reheater 322, steam drum 323, evaporator 324, preheater 325, deaerator 326, condensate tank 327, air-cooled island 328, etc.

[0080] Understandably, the above-mentioned technical features can be used in any combination without restriction.

[0081] The above embodiments merely illustrate specific implementations of the present invention, and their descriptions are relatively specific and detailed, but they should not be construed as limiting the scope of the present invention. It should be noted that those skilled in the art can freely combine the above technical features without departing from the concept of the present invention, and can also make several modifications and improvements, all of which fall within the protection scope of the present invention. Therefore, all equivalent transformations and modifications made with respect to the scope of the claims of the present invention should fall within the scope of the claims of the present invention.

Claims

1. A coordinated control method for a solar thermal power plant, characterized in that, include: The operating modes of the molten salt energy storage solar thermal power plant are determined; the operating modes include thermal storage mode, thermal release mode, and power generation mode. When the molten salt energy storage solar thermal power plant is in the thermal storage mode, the power generation mode of the steam turbine is selected according to the preset thermal storage capacity, the remaining thermal storage duration, and the current parameters of the hot salt tank; the power generation mode includes variable load power generation mode and minimum load power generation mode; When the power generation mode is the variable load power generation mode, the current power generation of the steam turbine is determined according to the preset thermal storage capacity, the remaining thermal storage duration, and the current parameters of the hot salt tank; When the power generation mode is the minimum load power generation mode, the current power generation of the steam turbine is determined according to the minimum load ratio of the rated power generation of the steam turbine. When the molten salt energy storage solar thermal power plant is in the heat release mode, the steam turbine is put into pressure control; the target flow rate of the hot salt tank outlet is obtained according to the preset heat release rate and the current parameters of the hot salt tank; the output parameters of the hot salt pump are controlled by closed-loop feedback according to the target flow rate of the hot salt tank outlet and the actual flow rate of the hot salt tank outlet. When the molten salt energy storage solar thermal power plant is in the power generation mode, the steam turbine is put into power control, the preset power generation power of the steam turbine is set, and the output parameters of the hot salt pump are controlled by closed-loop feedback according to the main steam pressure setpoint.

2. The coordinated control method for a solar thermal power plant according to claim 1, characterized in that, The step of selecting the turbine's power generation mode based on the preset thermal storage capacity, remaining thermal storage duration, and current parameters of the hot salt tank includes: The available power generation capacity of the steam turbine is obtained based on the preset thermal storage capacity, the current parameters of the hot salt tank, and the remaining thermal storage duration. The minimum power generation capacity of the steam turbine is obtained based on the rated power generation capacity of the steam turbine, the minimum load ratio, and the remaining heat storage time. The available generating capacity is compared with the minimum generating capacity; when the available generating capacity is less than the minimum generating capacity, the minimum load generating mode is adopted; when the available generating capacity is greater than or equal to the minimum generating capacity, the variable load generating mode is adopted.

3. The coordinated control method for a solar thermal power plant according to claim 2, characterized in that, The step of obtaining the available power generation capacity of the steam turbine based on the preset thermal storage capacity, the current parameters of the hot salt tank, and the remaining thermal storage duration includes: The remaining thermal storage capacity is obtained based on the current parameters of the hot salt tank and the remaining thermal storage duration. The current thermal storage capacity is obtained based on the current parameters of the hot salt tank. The available power generation capacity of the steam turbine is obtained based on the remaining thermal storage capacity, the current thermal storage capacity, and the preset thermal storage capacity.

4. The coordinated control method for a solar thermal power plant according to claim 3, characterized in that, The current parameters of the hot salt tank include the molten salt temperature, the current liquid level, the inlet flow rate, the molten salt heat capacity, and the dimensions of the hot salt tank. The remaining thermal storage capacity is obtained according to Formula 1; Formula 1 in, For the remaining thermal storage capacity, This refers to the inlet flow rate of the hot salt tank. For the remaining thermal storage time, For the molten salt heat capacity of the hot salt container, This refers to the molten salt temperature in the hot salt tank. The current thermal storage capacity is obtained according to Formula 2; Formula 2 in, For the current thermal storage capacity, This is the current liquid level in the hot salt tank. The cross-sectional area of ​​the hot salt container. The density of molten salt, For the molten salt heat capacity of the hot salt container, This refers to the molten salt temperature in the hot salt tank. The power generation capacity is obtained according to Formula 3; Formula 3 in, The available power generation capacity of the steam turbine. This represents the thermal storage capacity for the remaining thermal storage period. For the current thermal storage capacity, The preset thermal storage capacity; The minimum power generation capacity is obtained according to Formula 4; Formula 4 in, This represents the minimum generating capacity of the steam turbine. The rated power output of the steam turbine; This refers to the minimum load ratio; This represents the remaining thermal storage time.

5. The coordinated control method for a solar thermal power plant according to claim 2, characterized in that, When the power generation mode is the variable load power generation mode, the current power generation of the steam turbine is obtained according to Formula 5; Formula 5 in, This represents the current generating capacity of the turbine in variable load power generation mode. The available power generation capacity of the steam turbine. For the remaining thermal storage duration; and / or When the power generation mode is the minimum load power generation mode, the current power generation of the steam turbine is obtained according to Formula 6; Formula Six in, This represents the current generating capacity of the turbine in the lowest load power generation mode. The rated power output of the steam turbine; This refers to the minimum load ratio.

6. The coordinated control method for a solar thermal power plant according to any one of claims 1 to 5, characterized in that, The minimum load ratio is greater than or equal to 10% and less than or equal to 20%.

7. The coordinated control method for a solar thermal power plant according to any one of claims 1 to 5, characterized in that, The target flow rate at the outlet of the hot salt tank is obtained according to Formula 7; Formula 7 in, Where A is the target flow rate at the outlet of the hot salt tank, and A is the preset heat release rate. For the molten salt heat capacity of the hot salt container, This refers to the temperature at which the salt melts in the hot salt tank.

8. The coordinated control method for a solar thermal power plant according to any one of claims 1 to 5, characterized in that, The closed-loop feedback control of the hot salt pump output parameters based on the main steam pressure setpoint includes: Based on the given value of the main steam pressure, the output parameters of the hot salt pump are adjusted using a cascade PID controller; wherein, the main PID controller is the main steam pressure value, and the secondary PID controller is the hot salt tank outlet flow rate.

9. A coordinated control system for a solar thermal power plant, comprising a processor and a memory storing a computer program, characterized in that, When the processor executes the computer program, it implements the coordinated control method for a solar thermal power plant as described in any one of claims 1 to 8.

10. A molten salt energy storage solar thermal power plant, characterized in that, Includes the solar thermal power plant coordination control system as described in claim 9.

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