Solid-state heat storage device-based fast frequency modulation system and method for thermal power generating unit

Abstract

This invention discloses a rapid frequency regulation system and method for thermal power units based on solid-state thermal energy storage devices, relating to the field of thermal power generation frequency regulation technology. Its main objective is to address the problem of low load regulation efficiency in existing thermal power units. The system mainly includes a high-pressure heater group, a fluid connection network, a model predictive control unit, and at least one solid-state thermal energy storage device. The high-pressure heater group comprises multiple high-pressure heaters connected in sequence according to pressure levels. The fluid connection network includes multiple switchable preset connection methods, each of which selectively couples the solid-state thermal energy storage device between any two target high-pressure heaters in the high-pressure heater group. The model predictive control unit dynamically optimizes the heat storage or release ratio and flow distribution, and controls the switching of the fluid connection network and the feedwater flow based on the optimization results. This allows the unit's feedwater to be heated or cooled through the corresponding solid-state thermal energy storage device, thereby regulating the unit's power generation load. It is primarily used for frequency regulation of thermal power units.

Description

Technical Field

[0001] This invention relates to the field of frequency regulation technology for thermal power generation, and in particular to a rapid frequency regulation system and method for thermal power units based on solid-state thermal storage devices. Background Technology

[0002] With the large-scale grid connection of new energy sources, the power grid has placed higher demands on the response speed and regulation accuracy of frequency-regulated power supplies. Traditional thermal power units are limited by factors such as boiler thermal inertia and turbine valve regulation lag, making it difficult for their ramp-up rate and AGC response time to meet the second-level frequency regulation requirements. Existing technologies such as fuel-side regulation, feedwater recirculation valve frequency regulation, and main steam valve frequency regulation all suffer from response lag and low load regulation efficiency. Summary of the Invention

[0003] In view of this, the present invention provides a rapid frequency regulation system and method for thermal power units based on solid-state thermal storage devices, the main purpose of which is to solve the problem of low load regulation efficiency of existing thermal power units.

[0004] According to one aspect of the present invention, a rapid frequency regulation system for thermal power units based on a solid-state thermal storage device is provided, comprising: High-pressure heater assembly, fluid connection network, model prediction control unit and at least one solid-state thermal storage device; The high-pressure heater group includes multiple high-pressure heaters connected in sequence according to pressure level. The high-pressure side high-pressure heater is connected to the main feedwater inlet, and the low-pressure side high-pressure heater is connected to the feedwater pump inlet. The feedwater pump is used to inject the feedwater after it has passed through the high-pressure heater group and the solid thermal storage device into the boiler. The fluid connection network includes multiple switchable preset connection methods, any of which is used to selectively couple the solid thermal storage device to any two target high-pressure heaters in the high-pressure heater group; The model prediction and control unit is used to dynamically optimize the ratio and flow distribution of heat storage or heat release, and control the switching of the fluid connection network and the water supply flow based on the optimization results, so as to heat or cool the unit's water supply through the corresponding solid-state heat storage device and adjust the unit's power generation load.

[0005] Furthermore, the preset connection method includes multiple heat storage connection methods and multiple heat release connection methods; Any of the aforementioned thermal storage connection methods is used to lead the high-temperature feedwater from the high-pressure heater to the inlet of the low-pressure heater after cooling by the solid thermal storage device, thereby reducing the power generation load of the turbine. Any of the aforementioned heat-dissipating connection methods is used to heat the low-temperature feedwater from the feedwater pump outlet or the low-pressure-level high-pressure heater via the solid-state heat storage device, and then lead it to the outlet or inlet of the high-pressure-level high-pressure heater to increase the power generation load of the turbine.

[0006] Furthermore, the preset connection method includes multiple heat storage connection methods with different connection spans, and multiple heat release connection methods with different connection spans; Different connection spans for thermal storage have different load reduction ranges, and different connection spans for heat release have different load increase ranges. The number of heat storage connection methods and heat release connection methods is the same.

[0007] Furthermore, the model prediction control unit is specifically used for: Based on the received frequency modulation command, determine the frequency modulation type and load adjustment parameters; Based on the frequency regulation type, the load adjustment parameters, and the real-time operating parameters of the unit, the target connection method and the target thermal storage device are determined from multiple preset connection methods; The fluid connection network is switched to the target connection mode, and the water supply flow is controlled with a first flow rate to heat or cool the water supply through the target thermal storage device, thereby responding to the frequency modulation command.

[0008] Furthermore, the model prediction control unit is specifically used for: When the frequency regulation type is a significant load reduction and peak shaving, one of the thermal storage connection methods is determined as the target connection method, and the idle or matching thermal storage device is taken as the target thermal storage device. When the frequency regulation type is a large-scale load increase and peak shaving, one of the heat release connection methods is determined as the target connection method, and the heat storage device used in the previous load reduction process is taken as the target heat storage device.

[0009] Furthermore, the model prediction control unit is specifically used for: When the frequency regulation type is small-amplitude bidirectional AGC frequency regulation, if the load adjustment parameter is to reduce the load, then one of the thermal storage connection methods is determined as the target connection method, and the idle or matching thermal storage device is taken as the target thermal storage device; if the load adjustment parameter is to increase the load, then one of the heat release connection methods is determined as the target connection method, and the thermal storage device used in the previous load reduction process is taken as the target thermal storage device.

[0010] Furthermore, the heat storage connection method includes a first heat storage connection method to a fifth heat storage connection method, wherein the number of high-pressure heaters connected by each heat storage connection method increases sequentially, and the corresponding load adjustment range increases sequentially; the heat release connection method includes a first heat release connection method to a fifth heat release connection method, wherein the number of high-pressure heaters connected by each heat release connection method increases sequentially, and the corresponding load adjustment range increases sequentially. The model prediction control unit is specifically used for: In the process of determining the target connection method from the thermal storage connection methods, the target thermal storage connection method is determined from five thermal storage connection methods based on the range of load adjustment amplitude matched in the load adjustment parameters. In the process of determining the target connection method from the heat release connection methods, the target heat release connection method is determined from five heat release connection methods based on the range of the load adjustment amplitude matched in the load adjustment parameters. Among them, for heat storage and heat release connection methods used in pairs to respond to the same load adjustment range, the connection span of the target heat release connection method is greater than the connection span of the target heat storage connection method paired with it.

[0011] Furthermore, the model prediction control unit is specifically used for: During the low-load stable combustion phase of the unit in the thermal storage operation process where the frequency regulation type is large-scale load reduction and peak shaving, the target thermal storage connection mode is maintained, and the target thermal storage device is switched to a transitional thermal storage device. The feedwater flow rate is controlled by a second flow rate, and the feedwater is cooled by the transitional thermal storage device, wherein the second flow rate is less than the first flow rate when the target thermal storage device performs the cooling operation.

[0012] Furthermore, the model prediction control unit is specifically used for: During the execution of the thermal storage operation with the frequency regulation type of large-scale load increase and peak shaving, the transition connection is cut off, causing the unit's power generation load to increase in the first step. After the first step increase, the fluid connection network is switched to the target heat release connection mode that matches the load adjustment range, so that all the low temperature feedwater at the feedwater pump outlet flows through the transition heat storage device and is sent to the outlet of the high pressure heater group or the boiler inlet. At the same time, the boiler increases the main steam flow rate according to the allowable load increase rate, so that the unit's power generation load generates a second step increase and then continues to increase until the heat stored in the transition heat storage device is completely released. After the second step increase, the target heat release connection method is maintained, and all the low-temperature feedwater at the outlet of the feedwater pump flows through the target heat storage device for heating and then is sent out. At the same time, the boiler continues to increase the main steam flow, so that the unit's power generation load will generate a third step increase. After the third step increase, the target heat release connection is maintained, and all the low-temperature feedwater at the outlet of the feedwater pump flows through the target heat storage device for heating before being sent out. At the same time, the boiler continues to increase the main steam flow to the target value, causing the unit's power generation load to generate a fourth step increase and then continue to increase until the remaining heat stored in the target heat storage device is completely released and the unit load reaches the target high load.

[0013] According to another aspect of the present invention, a method for rapid frequency regulation of thermal power units based on solid-state thermal storage devices is provided. The method is applied to the aforementioned rapid frequency regulation system for thermal power units based on solid-state thermal storage devices. The system includes a high-pressure heater group, a fluid connection network, a model prediction control unit, and at least one solid-state thermal storage device. The high-pressure heater group includes multiple high-pressure heaters connected in sequence according to pressure levels. The high-pressure side high-pressure heater is connected to the main feedwater injection port, and the low-pressure side high-pressure heater is connected to the feedwater pump inlet. The feedwater pump is used to inject feedwater, after being processed by the high-pressure heater group and the solid-state thermal storage device, into the boiler. The fluid connection network includes multiple switchable preset connection modes. The method includes: The solid-state thermal storage device can be selectively coupled to any two target high-pressure heaters in the high-pressure heater group via any of the fluid connection networks; The model prediction control unit dynamically optimizes the ratio and flow distribution of heat storage or release, and controls the switching of the fluid connection network and the water supply flow based on the optimization results, so as to heat or cool the unit's feedwater through the corresponding solid-state thermal storage device and regulate the unit's power generation load.

[0014] By employing the above-described technical solutions, the technical solutions provided by the embodiments of the present invention have at least the following advantages: This invention provides a rapid frequency regulation system and method for thermal power units based on solid-state thermal energy storage devices. In this embodiment, the solid-state thermal energy storage device is selectively coupled to any two target high-pressure heaters in the high-pressure heater group via any part of a fluid connection network. Through the model prediction and control unit, the ratio of thermal energy storage or release and the flow distribution are dynamically optimized. Based on the optimization results, the switching of the fluid connection network and the feedwater flow are controlled to heat or cool the unit's feedwater through the corresponding solid-state thermal energy storage device, thereby regulating the unit's power generation load. Through the deep integration of the solid-state thermal energy storage unit and the regenerative system, rapid storage and release of thermal energy are achieved, significantly shortening the unit's response time to load commands, reducing coal consumption and wear during load changes, and ensuring the stability of key parameters such as main steam temperature and pressure. This greatly improves the overall efficiency and performance of thermal power units participating in rapid frequency regulation of the power grid.

[0015] The above description is merely an overview of the technical solution of the present invention. In order to better understand the technical means of the present invention, it can be implemented according to the contents of the specification. Furthermore, in order to make the above and other objects, features and advantages of the present invention more apparent and understandable, specific embodiments of the present invention are described below. Attached Figure Description

[0016] Various other advantages and benefits will become apparent to those skilled in the art upon reading the following detailed description of preferred embodiments. The accompanying drawings are for illustrative purposes only and are not intended to limit the invention. Furthermore, the same reference numerals denote the same parts throughout the drawings. In the drawings: Figure 1 This diagram illustrates a block diagram of a rapid frequency regulation system for thermal power units based on a solid-state thermal storage device, according to an embodiment of the present invention. Figure 2 This invention provides a block diagram of another rapid frequency regulation system for thermal power units based on a solid-state thermal storage device, according to an embodiment of the present invention. Figure 3 The flowchart illustrates a rapid frequency regulation method for thermal power units based on a solid-state thermal storage device, provided by an embodiment of the present invention. Detailed Implementation

[0017] Exemplary embodiments of the present disclosure will now be described in more detail with reference to the accompanying drawings. While exemplary embodiments of the present disclosure are shown in the drawings, it should be understood that the present disclosure may be implemented in various forms and should not be limited to the embodiments set forth herein. Rather, these embodiments are provided so that this disclosure will be thorough and complete, and will fully convey the scope of the disclosure to those skilled in the art.

[0018] To address the problem of low load regulation efficiency in existing thermal power units, this invention provides a rapid frequency regulation system for thermal power units based on a solid-state thermal energy storage device, such as... Figure 1 As shown, the system includes: a high-pressure heater assembly 11, a fluid connection network 12, a model prediction control unit 13, and at least one solid-state thermal storage device 14; The high-pressure heater group 11 includes multiple high-pressure heaters connected in sequence according to pressure level. The high-pressure side high-pressure heater is connected to the main feedwater inlet, and the low-pressure side high-pressure heater is connected to the feedwater pump inlet. The feedwater pump is used to inject feedwater, after being processed by the high-pressure heater group 11 and the solid-state thermal storage device 14, into the boiler. The fluid connection network 12 includes multiple switchable preset connection modes. Any of the preset connection modes is used to selectively couple the solid-state thermal storage device 14 between any two target high-pressure heaters in the high-pressure heater group 11, so as to heat or cool the feedwater between the target high-pressure heaters through the solid-state thermal storage device 14, thereby realizing the regulation of the power generation load of the unit.

[0019] In this embodiment of the invention, a solid-state thermal storage device 14 is integrated into the high-pressure heater system, and a flexible fluid connection network 12 is constructed to achieve bidirectional load regulation. The system consists of multiple high-pressure heater groups 11 connected in series according to pressure levels. The high-pressure side is connected to the boiler feedwater inlet, and the low-pressure side is connected to the feedwater pump inlet. The solid-state thermal storage device 14 can be one or more, and uses high-temperature resistant solid-state thermal storage materials, such as carbon-based composite materials. During load reduction, the system draws some high-temperature feedwater from the high-pressure heater group 11, cools it through the solid-state thermal storage device 14, and returns it to the high-pressure inlet of the lower-pressure level, achieving rapid power reduction by increasing the steam extraction rate. During load increase, the low-temperature feedwater from the feedwater pump outlet is heated by the solid-state thermal storage device 14 and directly sent to the high-pressure heater outlet or boiler inlet of the higher-pressure level, reducing steam extraction consumption and achieving rapid power increase. The model predictive control unit 13 is used to dynamically optimize the ratio of thermal storage or release, flow distribution and timing control to ensure that the frequency regulation target indicated by the frequency regulation command is achieved, such as ensuring that the AGC step response of 50MW is completed within 30 seconds and the ramp rate is not less than 3% of the rated load / minute.

[0020] In one embodiment of the present invention, for further explanation and limitation, the preset connection method includes multiple heat storage connection methods and multiple heat release connection methods; Any of the aforementioned thermal storage connection methods is used to lead the high-temperature feedwater from the high-pressure heater to the inlet of the low-pressure heater after cooling by the solid thermal storage device, thereby reducing the power generation load of the turbine. Any of the aforementioned heat-dissipating connection methods is used to heat the low-temperature feedwater from the feedwater pump outlet or the low-pressure-level high-pressure heater via the solid-state heat storage device, and then lead it to the outlet or inlet of the high-pressure-level high-pressure heater to increase the power generation load of the turbine.

[0021] In this embodiment of the invention, the fluid connection network includes multiple pre-designed pipeline connection methods that can be switched via valve groups, mainly divided into two categories: heat storage connection methods and heat release connection methods. These connection methods are the key paths to achieve dynamic energy transfer and rapid load adjustment.

[0022] For any thermal energy storage connection method, its core function is as follows: when a rapid reduction in the unit's power generation load is required, some or all of the high-temperature feedwater from the outlet of the high-pressure heaters (such as #0 and #1) in the high-pressure heater group is drawn out and flows through the solid-state thermal energy storage device for cooling (i.e., releasing heat to the storage device), and then it is delivered to the inlet of the relatively lower-pressure heaters (such as #3 and #2). Essentially, this process "intercepts" and stores a portion of the high-grade extraction steam energy that would otherwise be used to heat the feedwater in the high-pressure heaters in the solid-state thermal energy storage device by transferring it to the feedwater flow. Because the feedwater temperature decreases as it flows through subsequent heaters, the extraction steam volume of the corresponding turbine stage must be increased to heat it to the set temperature. This increased extraction steam no longer enters the turbine's low-pressure cylinder to perform work, resulting in a rapid decrease in the turbine's output power, thus achieving the load reduction target.

[0023] For any exothermic connection method, its core function is as follows: when a rapid increase in unit power generation load is required, some or all of the low-temperature feedwater from the feedwater pump outlet, or the lower-temperature feedwater from the outlet of the low-pressure-level high-pressure heater, is drawn out and heated through a solid-state thermal storage device (i.e., heat is absorbed from the thermal storage device), and then transported to the outlet (directly into the boiler economizer) or inlet of the high-pressure-level high-pressure heater. This process utilizes the thermal energy stored in the solid-state thermal storage device to directly increase the feedwater temperature entering the boiler or the high-pressure-level high-pressure heater. Because the feedwater is preheated before entering the high-pressure heater system or within the high-pressure heater system, the required turbine extraction steam volume is correspondingly reduced. This "saved" extraction steam can remain in the turbine to continue expanding and doing work, thereby rapidly increasing the unit's output power and achieving the load increase target.

[0024] The model predictive control unit dynamically decides and selects the optimal heat storage or release connection method based on real-time grid AGC commands, target load curves, unit operating status, and the heat storage status of each solid-state thermal storage module. It also precisely controls the opening degree of each pipeline valve, the speed of the booster pump, and the switching sequence. In this way, the system can flexibly and accurately respond to load changes of different amplitudes and directions, maximizing frequency regulation response speed and accuracy while ensuring the safe operation of the main unit equipment.

[0025] In one embodiment of the present invention, for further explanation and limitation, the preset connection method includes multiple heat storage connection methods with different connection spans, and multiple heat release connection methods with different connection spans; Among them, the heat storage connection methods with different connection spans each correspond to different load reduction ranges, and the heat release connection methods with different connection spans each correspond to different load increase ranges; the number of heat storage connection methods and heat release connection methods is the same.

[0026] In this embodiment of the invention, the system includes multiple thermal storage connection methods with different connection spans. The connection span primarily refers to the number of heater stages traversed between the high-pressure intake heater and the low-pressure return heater. A larger connection span (e.g., from intake from heater #0 to return to heater #3) means higher quality heat transferred and stored, greater flow regulation potential, and thus a larger single load reduction, suitable for deep peak shaving or large-step load reduction scenarios. Conversely, a smaller connection span (e.g., from intake from heater #1 to return to heater #2) is suitable for small, frequent AGC power reduction command responses. For example, a large span method is used to handle large load reductions such as 120MW, corresponding to a connection from intake from heater #0 to return to heater #3. A medium span method is used to handle standard AGC power reduction steps such as 50MW, corresponding to a connection from intake from heater #0 to return to heater #2. A small span method can be used for more precise fine-tuning, corresponding to connections spanning one or two heater stages. Each method is implemented through pre-set pipelines and valves. The model predictive control unit automatically selects and activates the corresponding optimal span connection method based on the target load reduction magnitude. Similarly, the system also includes multiple heat dissipation connection methods with different connection spans. Here, the connection span mainly refers to the path length and heater bypass degree involved from the low-temperature side of the water intake (feed pump outlet or low-pressure-level high-pressure heater outlet) to the high-temperature side of the final return water (high-pressure-level high-pressure heater outlet or inlet).

[0027] In a preferred embodiment, the number of thermal storage connections and thermal release connections are the same, and they are configured in pairs. That is, for each thermal storage connection used for load reduction within a specific range, the system pre-sets a corresponding thermal release connection used for load increase within a similar range. This paired design ensures the system's ability to respond to bidirectional, symmetrical load step commands, forming a complete frequency regulation cycle.

[0028] In one embodiment of the present invention, for further explanation and limitation, the model prediction control unit is specifically used to: determine the frequency modulation type and load adjustment parameters based on the received frequency modulation command; determine the target connection mode and target thermal storage device from multiple preset connection modes based on the frequency modulation type, the load adjustment parameters and the real-time operating parameters of the unit; control the fluid connection network to switch to the target connection mode, and control the feedwater flow rate with a first flow rate, so as to heat or cool the feedwater through the target thermal storage device, thereby realizing the response to the frequency modulation command.

[0029] In this embodiment of the invention, the model prediction control unit receives frequency regulation commands (such as automatic generation control (AGC) commands or primary frequency regulation signals) from the power grid in real time. The unit parses the commands, determines the frequency regulation type (e.g., whether it is "rapid ramp-up," "large step load reduction," or "small AGC bidirectional regulation") based on the command's characteristics (such as step direction, amplitude, and rate of change requirements), and extracts specific load adjustment parameters, including the target load value and the desired adjustment time or rate.

[0030] After clarifying the frequency regulation requirements, this unit makes a comprehensive decision based on the unit's real-time operating parameters. These real-time operating parameters include, but are not limited to: the current actual generating load of the unit, main steam pressure and flow rate, feedwater temperature and pressure at the inlet and outlet of each high-pressure heater, and the current storage / release status (temperature, available heat capacity) of each solid thermal storage device (modules A, B, I, II, etc.). Based on the built-in dynamic model of the thermal power unit-thermal storage system coupling, the model predictive control unit performs rolling optimization calculations: according to the frequency regulation type, load adjustment parameters, and real-time operating parameters, it determines the optimal target connection method from the preset multiple thermal storage and release connection methods of the fluid connection network. For example, for a 50MW load reduction command, a specific thermal storage connection method of drawing water from the medium-pressure side back to the #2 high-pressure heater might be chosen; for a rapid load reduction of 120MW, a large-span thermal storage connection method of drawing water from the #0 high-pressure heater back to the #3 high-pressure heater might be chosen. Simultaneously, the target solid thermal storage device for performing this energy transfer operation is determined. The decision-making criteria include the current temperature of the method (whether it is in the high-efficiency operating range), the available heat capacity, and the matching relationship with the target connection method (e.g., a specific connection method is pre-set to be physically connected to a specific thermal storage module).

[0031] After the decision is made, the model predictive control unit outputs a control signal to control the valve group in the fluid connection network, switching the system pipeline to the selected target connection mode and establishing the corresponding feedwater flow path. Along this established path, the feedwater flow through the target thermal storage device is precisely controlled by adjusting the booster pump speed and / or the opening of the pipeline regulating valves, using a first flow rate. This first flow rate is calculated through optimization to utilize the heating or cooling capacity of the thermal storage device in the most efficient and stable manner to achieve the required load changes. During the response to frequency regulation commands, the unit continuously monitors the system status and performs feedforward-feedback composite control based on model predictions. For example, it dynamically fine-tunes the first flow rate, coordinates the slow adjustment of the boiler combustion rate, ensures stable main steam parameters, and minimizes thermal stress on the main unit equipment while meeting frequency regulation speed requirements.

[0032] In one embodiment of the present invention, for further explanation and limitation, the model prediction control unit is specifically used for: When the frequency regulation type is a significant load reduction and peak shaving, one of the thermal storage connection methods is determined as the target connection method, and the idle or matching thermal storage device is taken as the target thermal storage device. When the frequency regulation type is a large-scale load increase and peak shaving, one of the heat release connection methods is determined as the target connection method, and the heat storage device used in the previous load reduction process is taken as the target heat storage device.

[0033] In this embodiment of the invention, when a received frequency regulation command requires a significant load reduction within a short period of time (e.g., several minutes) (e.g., a reduction exceeding 10% of the rated load, or exceeding 100MW), and the command duration is relatively long (e.g., participating in deep peak shaving for several hours), it is determined to be a significant load reduction peak shaving. The model prediction control unit selects a connection method with a larger connection span and stronger single-time heat storage capacity from a set of preset thermal storage connection methods as the target connection method. For example, a connection method is selected that draws water from the highest pressure level #0 high-pressure heater and returns water to the lowest pressure level #3 high-pressure heater (or lower level) to achieve the maximum rapid increase in steam extraction and a step drop in power. At the same time, all solid thermal storage devices are searched, and thermal storage devices that are currently idle (temperature at the set lower limit, large available thermal storage capacity) or specially designed to match the pipeline of the target connection method are prioritized as target thermal storage devices. For example, thermal storage module A is selected to receive the massive amount of heat energy transferred during this significant load reduction process.

[0034] When a unit is operating at low load and receives an instruction to significantly increase the load within a short period (e.g., rapidly increasing from deep load adjustment to near rated load), it is determined to be a significant load increase for peak shaving. The model predictive control unit selects the connection method with the largest connection span and the most thorough bypass of the high-pressure heater system from a number of preset heat release connection methods as the target connection method. For example, a full bypass heat release method is selected, where all feedwater pump outlet water is heated by a thermal storage device and then directly sent to the #0 high-pressure heater outlet (or boiler inlet). The thermal storage device that has stored a large amount of heat energy during the previous significant load reduction peak shaving process (or during a long period of low load operation) is directly identified as the target thermal storage device for this load increase. For example, thermal storage module A and / or thermal storage module B, which have been fully charged during the deep load reduction phase, are used.

[0035] In one embodiment of the present invention, for further explanation and limitation, the model prediction control unit is specifically used to: when the frequency regulation type is small-amplitude bidirectional AGC frequency regulation, if the load adjustment parameter is load reduction, then one of the thermal storage connection methods is determined as the target connection method, and the idle or matching thermal storage device is used as the target thermal storage device; if the load adjustment parameter is load increase, then one of the heat release connection methods is determined as the target connection method, and the thermal storage device used in the previous load reduction process is used as the target thermal storage device.

[0036] In this embodiment of the invention, when the received frequency regulation command is a continuous, bidirectional, small-amplitude (e.g., a step amplitude of 2%-5% of the rated load, such as 50MW) high-frequency Automatic Generation Control (AGC) command, it is determined to be a small-amplitude bidirectional AGC frequency regulation. Based on the current load level and the target reduction amplitude, a connection method with a matching span and amplitude is selected from a set of preset thermal storage connection methods as the target connection method. A medium-span connection (e.g., water intake from #0 high-pressure heater back to #2 high-pressure heater) is typically used. Simultaneously, a thermal storage device that is currently idle and whose thermal parameters (e.g., operating temperature range) match the current feedwater conditions is preferentially selected as the target thermal storage device and marked as being in thermal storage mode. For example, during a 600MW→550MW step change, thermal storage module I is selected and activated. Based on the current load level and the target increase amplitude, a thermal release connection method with a span corresponding to the thermal storage connection method used in the previous load reduction but with the opposite path is selected from a set of preset heat release connection methods as the target connection method. The thermal storage device that just completed its thermal storage operation during the previous adjacent load reduction process is directly selected as the target thermal storage device for the current load increase. For example, immediately following a load increase command from 550MW to 600MW, "thermal storage module I," which just stored heat during the 600MW to 550MW process, is used to release heat. This paired use and on-site heat circulation process enables rapid response to AGC bidirectional step commands. At the same time, it avoids long-distance or complex heat transfer between different modules, simplifies control, and improves response speed and system efficiency.

[0037] In a specific application example, the step amplitude of the grid AGC command is set to 5%Pe (50MW), and the unit's power generation load range is 40%THA-60%THA (400MW-600MW). The unit's pure condensing power generation load of 400MW corresponds to a boiler main steam output of 958t / h; the unit's pure condensing power generation load of 600MW corresponds to a boiler main steam output of 1474.6t / h; the maximum flow capacity of the unit's feedwater system is 2834.1t / h (VWO condition); under pure condensing conditions, the actual boiler load increase / decrease rate is 1.67%Pe / min. During the process of achieving a power reduction step (600MW→550MW), high-temperature water (869.3t / h) is pumped from the #0 high-pressure heater to the thermal storage module I to cool it to 204℃, thus achieving a 50MW step response time ≤30 seconds. 60%THA↘55%THA Load Step Condition: When the unit's pure condensing power generation load is 60%THA (600MW), a portion of high-temperature feedwater is rapidly drawn from the outlet of the #0 high-temperature water heater. After passing through the booster pump and solid-state thermal storage device, it is then supplied with feedwater according to… Figure 2As shown in thermal storage method 2, the steam is returned to the inlet of the #2 high-pressure heater, increasing the feedwater flow between the inlets and outlets of the #2-#0 high-pressure heaters. This increases the steam extraction rate of the #2, #1, and #0 high-pressure heaters, enabling the unit's power generation load to rapidly decrease to 55% THA (550MW), a rapid reduction of 50MW. As the boiler gradually reduces the main steam flow at its normal load reduction rate, the high-temperature feedwater flow extracted from the #0 high-pressure heater outlet is simultaneously reduced to zero, maintaining the unit's power generation load at 550MW throughout this process. The maximum pumping rate at the outlet of the #0 high-pressure heater is 869.3 t / h, with a pressure of 21.69 MPa and a temperature of 295℃; the maximum makeup water rate at the inlet of the #2 high-pressure heater is 869.3 t / h, with a pressure of 21.72 MPa and a temperature of 204℃; the maximum feedwater flow rate between the inlets and outlets of the #2 and #0 high-pressure heaters is 2343.9 t / h; the maximum main steam flow rate is 1474.6 t / h, with a pressure of 20.3 MPa and a temperature of 605℃; and the minimum main steam flow rate is 1340.2 t / h, with a pressure of 18.55 MPa and a temperature of 605℃. During the 15-30s interval, the pumping rate at the outlet of the #0 high-pressure heater reaches its maximum value. The total duration of the process is approximately 195s, and the heat released by the high-temperature feedwater is stored in thermal storage module I.

[0038] Similarly, the operating process of the 55%THA↘50%THA, 50%THA↘45%THA, and 45%THA↘40%THA load step conditions is the same as that of the 60%THA↘55%THA load step condition. Specifically, in the 55%THA↘50%THA load step condition, the maximum pumping flow at the outlet of the #0 high-pressure heater is 885.9 t / h, pressure is 19.58 MPa, and temperature is 288℃; the maximum makeup water flow at the inlet of the #2 high-pressure heater is 885.9 t / h, pressure is 19.61 MPa, and temperature is 199℃; the maximum feedwater flow between the inlets and outlets of the #2 and #0 high-pressure heaters is 2226.1 t / h; the maximum main steam flow is 1340.2 t / h, pressure is 18.55 MPa, and temperature is 605℃; and the minimum main steam flow is 1209.1 t / h, pressure is 16.85 MPa, and temperature is 605℃. During the 15-30s period, the pumping rate at the outlet of the #0 high-temperature water supply reaches its maximum value. The total duration of the process is approximately 195s, and the heat released by the high-temperature feedwater is stored in the thermal storage module II.

[0039] Under the step load condition of 50% THA ↘ 45% THA, the maximum pumping flow rate at the outlet of the #0 high-pressure water heater is 905.9 t / h, pressure is 17.59 MPa, and temperature is 282℃; the maximum makeup water flow rate at the inlet of the #2 high-pressure water heater is 905.9 t / h, pressure is 17.59 MPa, and temperature is 194℃; the maximum feedwater flow rate between the inlets and outlets of the #2 and #0 high-pressure water heaters is 2114.9 t / h; the maximum main steam flow rate is 1209.1 t / h, pressure is 16.85 MPa, and temperature is 605℃; the minimum main steam flow rate is 1081.4 t / h, pressure is 15.31 MPa, and temperature is 605℃. During this process, the pumping flow rate at the outlet of the #0 high-pressure water heater reaches its maximum value between 15 and 30 seconds. The total duration of the process is approximately 195 seconds, and the heat released by the high-temperature feedwater is stored in the thermal storage module III. Under the step load condition of 45%THA↘40%THA, the maximum pumping flow rate at the outlet of the #0 high-pressure water heater is 929.7 t / h, pressure is 15.83 MPa, and temperature is 274℃; the maximum makeup water flow rate at the inlet of the #2 high-pressure water heater is 929.7 t / h, pressure is 15.86 MPa, and temperature is 189℃; the maximum feedwater flow rate between the inlets and outlets of the #2 and #0 high-pressure water heaters is 2011.1 t / h; the maximum main steam flow rate is 1081.4 t / h, pressure is 15.31 MPa, and temperature is 605℃; the minimum main steam flow rate is 958 t / h, pressure is 14.51 MPa, and temperature is 605℃. During this process, the pumping flow rate at the outlet of the #0 high-pressure water heater reaches its maximum value between 15 and 30 seconds, and the total duration of the process is approximately 195 seconds. The heat released by the high-temperature feedwater is stored in the thermal storage module IV.

[0040] During the process of achieving a power increase step (550MW→600MW), the feedwater outlet water (1059.4t / h) is heated to 265.1℃ by module I and then sent back to the high-pressure heater to achieve synchronous completion of the reverse step. The 55%THA→60%THA load step condition includes: when the unit's pure condensing power generation load is 55%THA (550MW), the high-temperature feedwater from the feedwater pump outlet is rapidly sent to the solid-state thermal storage device, according to... Figure 2As shown in heat release method 3, the heat is returned to the inlet of the #0 high-pressure heater, reducing the feedwater flow between the inlets and outlets of the #4-#1 high-pressure heaters, and reducing the steam extraction of the #4, #3, #2, and #1 high-pressure heaters. This allows the unit's power generation load to rapidly increase to 60% THA (600MW), quickly increasing the unit's power generation load by 50MW. As the boiler gradually increases the main steam flow at its normal load-increasing rate, the low-temperature feedwater flow from the feedwater pump outlet to the solid-state thermal storage device is simultaneously reduced to zero, maintaining the unit's power generation load at 600MW. Specifically, the maximum low-temperature feedwater flow from the feedwater pump outlet to the solid-state thermal storage device is 1059.4 t / h, pressure 19.58 MPa, and temperature 169℃; the minimum main steam flow is 1340 t / h, pressure 18.55 MPa, and temperature 605℃; and the maximum main steam flow is 1474.6 t / h, pressure 20.3 MPa, and temperature 605℃. During the 15-30s interval, the flow rate of the low-temperature feedwater from the feedwater pump outlet to the solid-state thermal storage device reaches its maximum value. The total duration of the process is approximately 195s. The heat used to heat the low-temperature feedwater comes from the heat stored in thermal storage module I during the 60%THA↘55%THA load step condition. Similarly, the operating process for the 50%THA↗55%THA, 45%THA↗50%THA, and 40%THA↗45%THA load step conditions is the same as that for the 55%THA↗60%THA load step condition. During the 50%THA to 55%THA load step operation, the maximum flow rate of the cryogenic feedwater from the feedwater pump outlet to the solid-state thermal storage unit is 1014.7 t / h, with a pressure of 17.59 MPa and a temperature of 165℃; the minimum main steam flow rate is 1209.1 t / h, with a pressure of 16.85 MPa and a temperature of 605℃; and the maximum main steam flow rate is 1340.2 t / h, with a pressure of 18.55 MPa and a temperature of 605℃. The cryogenic feedwater flow rate from the feedwater pump outlet to the solid-state thermal storage unit reaches its maximum value between 15 and 30 seconds, with a total duration of approximately 195 seconds. The heat used to heat the cryogenic feedwater comes from the heat stored in thermal storage module II during the 55%THA to 50%THA load step operation. Under the 45%THA to 50%THA load step condition, the maximum flow rate of the cryogenic feedwater from the feedwater pump outlet to the solid-state thermal storage unit is 973.4 t / h, the pressure is 15.84 MPa, and the temperature is 162℃; the minimum main steam flow rate is 1081.4 t / h, the pressure is 15.31 MPa, and the temperature is 605℃; the maximum main steam flow rate is 1209.1 t / h, the pressure is 16.85 MPa, and the temperature is 605℃. During the 15-30s interval, the cryogenic feedwater flow rate from the feedwater pump outlet to the solid-state thermal storage unit reaches its maximum value. The total duration of the process is approximately 195 seconds. The heat used to heat the cryogenic feedwater comes from the heat stored in thermal storage module III under the 50%THA to 45%THA load step condition.

[0041] Under the 40%THA to 45%THA load step condition, the maximum flow rate of the cryogenic feedwater from the feedwater pump outlet to the solid-state thermal storage unit is 922 t / h, the pressure is 14.89 MPa, and the temperature is 158℃; the minimum main steam flow rate is 958 t / h, the pressure is 14.51 MPa, and the temperature is 605℃; the maximum main steam flow rate is 1081.4 t / h, the pressure is 15.31 MPa, and the temperature is 605℃. During the 15-30s interval, the cryogenic feedwater flow rate from the feedwater pump outlet to the solid-state thermal storage unit reaches its maximum value. The total duration of the process is approximately 195s. The heat used to heat the cryogenic feedwater comes from the heat stored in thermal storage module IV under the 45%THA to 40%THA load step condition.

[0042] In one embodiment of the present invention, for further explanation and limitation, the heat storage connection method includes a first heat storage connection method to a fifth heat storage connection method, wherein the number of high-pressure heaters connected by each heat storage connection method increases sequentially, and the corresponding load adjustment range increases sequentially; the heat release connection method includes a first heat release connection method to a fifth heat release connection method, wherein the number of high-pressure heaters connected by each heat release connection method increases sequentially, and the corresponding load adjustment range increases sequentially. The model prediction control unit is specifically used to: determine the target heat release connection method from five heat storage connection methods in the process of determining the target heat storage connection method from the heat storage connection methods, based on the amplitude range matched by the load adjustment amplitude in the load adjustment parameters; In the process of determining the target connection method from the heat release connection methods, the target connection method is determined from five heat release connection methods based on the range of load adjustment amplitude matched in the load adjustment parameters.

[0043] In this embodiment of the invention, the number of high-pressure heaters connected in each of the first to fifth methods increases sequentially. For example, the first method may only connect one high-pressure heater (e.g., taking water from the inlet of high-pressure heater #0 and returning it to the outlet of high-pressure heater #0), while the fifth method may connect all or most of the high-pressure heaters (e.g., taking water from the inlet of high-pressure heater #0 and returning it to the outlet of high-pressure heater #4). As the connection span increases, the total amount of heat energy that can be transferred and stored increases, and the load reduction (power reduction) that can be achieved in a single operation increases sequentially. The fifth thermal storage connection method has the largest single load reduction capacity and is suitable for deep peak shaving; the first thermal storage connection method has the weakest capacity and is suitable for the finest fine-tuning.

[0044] For the heat release connection methods, the number of high-pressure heaters connected or bypassed increases sequentially from the first to the fifth method. The first heat release method may only involve local heating (such as heat exchange between adjacent high-pressure heaters), while the fifth heat release method may achieve almost complete bypass of the entire high-pressure heater system. As the span increases, the amount of steam extraction that can be "replaced" by the heat release method increases, thus the load increase (power increase) that can be achieved in a single operation increases sequentially. The fifth heat release connection method has the largest single load increase capacity and is suitable for rapid ramp-up. Each heat storage connection method, according to its sequence (first to fifth), corresponds to a load reduction range with both the lower and upper limits increasing sequentially. First heat storage connection method: corresponding reduction range is (0, ΔP1] MW. Second heat storage connection method: corresponding reduction range is (ΔP1, ΔP2] MW. Each heat release connection method, according to its sequence (first to fifth), also corresponds to a load increase range with both the lower and upper limits increasing sequentially.

[0045] It should be noted that for heat storage and heat release connection methods paired together to respond to the same load adjustment range, the connection span of the target heat release connection method is larger than the connection span of its paired target heat storage connection method. That is, by adopting an asymmetrical span design and its correlation with the range, the load reduction range corresponding to the same sequence of heat storage connection methods is larger than the load increase range corresponding to the same sequence of heat release connection methods. By using a heat release connection method with a larger span (such as a more thorough bypass of the high-pressure heater system), heat energy can be released with higher heat-to-work conversion efficiency in a single operation. This compensates for the relatively conservative upper limit of the heat release range set due to the slow dynamics of the boiler, ensuring that in practice, a rapid load increase response symmetrical to the load reduction can ultimately be achieved.

[0046] In one embodiment of the present invention, for further explanation and limitation, the model prediction control unit is specifically used for: During the low-load stable combustion phase of the unit in the thermal storage operation process where the frequency regulation type is large-scale load reduction and peak shaving, the target thermal storage connection mode is maintained, and the target thermal storage device is switched to a transitional thermal storage device. The feedwater flow rate is controlled by a second flow rate, and the feedwater is cooled by the transitional thermal storage device.

[0047] In this embodiment of the invention, the second flow rate is less than the first flow rate when the target thermal storage device performs a cooling operation. In a scenario responding to a significant load reduction and peak shaving command, when the unit's power generation load has rapidly decreased to the target low load value (e.g., a deep load reduction of 300MW) and needs to operate stably under this load for a period of time (i.e., the low load stable combustion phase), the model predictive control unit executes a refined transition control strategy to optimize the system state and prepare for a possible subsequent rapid load increase. At the start of the low load stable combustion phase, the unit command fluid connection network continues to maintain the target thermal storage connection method used when performing a significant load reduction (e.g., the third thermal storage connection method, corresponding to a large-span connection from #0 high-pressure heater to #3 high-pressure heater). This maintains the basic path of using thermal storage operations to assist in stabilizing the unit's extraction steam system and feedwater temperature. Simultaneously, the valve group in the unit control fluid connection network switches the target thermal storage device for thermal storage operations from the main thermal storage device used for rapid load reduction (e.g., thermal storage module A) to a standby thermal storage device dedicated to the transition phase, i.e., the transition thermal storage device (e.g., thermal storage module B).

[0048] After the switchover is complete, the model predictive control unit implements transitional thermal storage control: the unit controls relevant pumps and valves to control the feedwater flow through the transitional thermal storage device (thermal storage module B) at a second flow rate. This second flow rate is significantly lower than the first flow rate used during the previous rapid load reduction phase to cool the primary target thermal storage device (such as thermal storage module A). For example, the first flow rate might be as high as 1827 t / h, while the second flow rate might be controlled at around 1060.5 t / h. This process is still a cooling operation, meaning that some of the heat from the high-temperature feedwater continues to be transferred and stored in the solid thermal storage material. However, due to the reduced flow rate, the heat power transfer rate also decreases accordingly.

[0049] It should be noted that a portion of additional, relatively low-grade thermal energy is stored in the transitional thermal storage device (storage module B). This energy is not used to achieve a large power step increase, but rather serves as "reserve launch energy" for the initial stage of subsequent rapid load increase, enabling a smoother and faster start-up of the load increase process. By implementing a composite control strategy of maintaining a wide-span connection, switching to the standby thermal storage device, and using low-flow transitional thermal storage during the low-load stable combustion stage after a significant load reduction and peak shaving, not only is the safety and stability of the unit's low-load operation ensured, but the system's energy storage state is also proactively optimized, providing energy pre-setting for the next frequency regulation action (rapid load increase).

[0050] In a rapid ramp-up example, the minimum generating load for the unit under deep-load operation is set at 300MW (30% THA); the unit's pure condensing generating load of 420MW corresponds to a boiler main steam output of 1007.1t / h; the unit's pure condensing generating load of 300MW corresponds to a boiler main steam output of 717.8t / h; the maximum flow capacity of the unit's feedwater system is 2834.1t / h (VWO condition); under pure condensing condition, the actual boiler load increase / decrease rate is 1.67%Pe / min.

[0051] When the unit's pure condensing power generation load is 420MW, a portion of high-temperature feedwater is rapidly drawn from the outlet of the #0 high-temperature water heater. After passing through a booster pump and a solid-state thermal storage device, it is then... Figure 2 As shown in thermal storage method 3, the water is returned to the inlet of the #3 high-pressure heater, increasing the feedwater flow between the inlets and outlets of the #3-#0 high-pressure heaters. This increases the steam extraction rate of the #3, #2, #1, and #0 high-pressure heaters, enabling the unit's power generation load to rapidly decrease to 300MW, a reduction of 120MW. As the boiler gradually reduces the main steam flow at its normal load reduction rate, the high-temperature feedwater flow extracted from the #0 high-pressure heater outlet is simultaneously reduced to zero, maintaining the unit's power generation load at 300MW throughout this process. The maximum pumping rate at the outlet of the #0 high-pressure water heater is 1827 t / h, with a pressure of 15.26 MPa and a temperature of 258.6℃; the maximum makeup water rate at the inlet of the #3 high-pressure water heater is 1827 t / h, with a pressure of 15.31 MPa and a temperature of 145.4℃; the maximum feedwater flow rate between the inlets and outlets of the #3 and #0 high-pressure water heaters is 2834.1 t / h; the maximum main steam flow rate is 1007.1 t / h, with a pressure of 14.83 MPa and a temperature of 605℃; and the minimum main steam flow rate is 717.8 t / h, with a pressure of 12.68 MPa and a temperature of 605℃. During this process, the pumping rate at the outlet of the #0 high-pressure water heater reaches its maximum value between 15 and 30 seconds, with a total duration of approximately 435 seconds. The heat released by the high-temperature feedwater is stored in thermal storage module A. High-temperature water (1827t / h, 258.6℃) is drawn from the #0 high-pressure heater, cooled to 145.4℃ through the thermal storage module A, and then injected into the #3 high-pressure heater; the increased steam extraction rate causes the load to drop rapidly by 120MW; the material temperature of the thermal storage module A rises from 154℃ to 171℃, thereby achieving a rapid load reduction (420MW→300MW).

[0052] In one embodiment of the present invention, for further explanation and limitation, the model prediction control unit is specifically used for: During the execution of the thermal storage operation with the frequency regulation type of large-scale load increase and peak shaving, the transition connection is cut off, causing the unit's power generation load to increase in the first step. After the first step increase, the fluid connection network is switched to the target heat release connection mode that matches the load adjustment range, so that all the low temperature feedwater at the feedwater pump outlet flows through the transition heat storage device and is sent to the outlet of the high pressure heater group or the boiler inlet. At the same time, the boiler increases the main steam flow rate according to the allowable load increase rate, so that the unit's power generation load generates a second step increase and then continues to increase until the heat stored in the transition heat storage device is completely released. After the second step increase, the target heat release connection method is maintained, and all the low-temperature feedwater at the outlet of the feedwater pump flows through the target heat storage device for heating and then is sent out. At the same time, the boiler continues to increase the main steam flow, so that the unit's power generation load will generate a third step increase. After the third step increase, the target heat release connection is maintained, and all the low-temperature feedwater at the outlet of the feedwater pump flows through the target heat storage device for heating before being sent out. At the same time, the boiler continues to increase the main steam flow to the target value, causing the unit's power generation load to generate a fourth step increase and then continue to increase until the remaining heat stored in the target heat storage device is completely released and the unit load reaches the target high load.

[0053] In this embodiment of the invention, when responding to a significant load increase and peak shaving command, the model predictive control unit executes a phased, multi-step refined coordinated control strategy to maximize the release of previously stored thermal energy and achieve rapid and stable continuous load ramp-up. This strategy is specifically executed in the following four stages: Stage 1 (Initial Rapid Response): First, the unit disconnects the ongoing transitional connection to the transitional thermal storage device. This operation instantly restores the feedwater flow rate of the high-pressure heater system, drastically reduces the steam extraction rate, and utilizes the inherent thermal storage of the boiler and pipelines to cause a first-step increase in the unit's power generation load, achieving an initial rapid response. Stage 2 (Transitional Energy Storage Release and Boiler Start-up Follow-up): Subsequently, the unit controls the fluid connection network to switch to the target heat release connection mode matching the current load range, and guides all low-temperature feedwater from the feedwater pump outlet to be heated by the transitional thermal storage device before directly sending it to the high-pressure heater group outlet or boiler inlet, completely bypassing the high-pressure heater system. Simultaneously, the boiler begins to increase the main steam flow rate according to the allowable load ramp-up rate. Under the combined effect of both, the unit's power generation load experiences a second-stage increase, which continues to grow until the reserve heat stored in the transitional thermal storage device is completely released, completing the accelerated start-up of the load increase process. The third stage (first release of main energy storage): Based on the venting of the transitional energy storage and the continuous combustion of the boiler, the unit maintains the target heat release connection mode, switching all feedwater passages to flow through the main target thermal storage device for heating before being sent out. Combined with the continued increase in the boiler's main steam flow, the unit's power generation load experiences a third-stage increase, beginning to absorb the main energy stored in the main method during the load reduction phase. The fourth stage (complete release of main energy storage and target achievement): To finally complete the ramp-up, the unit continues to maintain the target heat release connection mode, still allowing all feedwater to flow through the main target thermal storage device for heating. Simultaneously, the boiler continues to increase the main steam flow to the target high load value. This stage causes the unit's power generation load to experience a fourth-stage increase, which then continues to grow and eventually stabilizes at the target high load value, driven by the boiler reaching the target steam flow and the complete release of the remaining heat from the main method.

[0054] In a specific application example, the first phase of rapid load increase (300MW→367MW) includes: when the unit's generating load is 300MW, and after the transition phase, the boiler's main steam output has reached 877.9t / h, and the pumping flow rate at the #0 high-pressure heater outlet has reached 1060.5t / h, the pumping flow rate at the #0 high-pressure heater outlet is rapidly reduced to zero. That is, the feedwater flow rate between the #3 and #0 high-pressure heater inlets and outlets is rapidly restored from 1938.5t / h to 877.9t / h. The steam extraction rates of the #3, #2, #1, and #0 high-pressure heaters are also rapidly reduced, enabling the unit's generating load to rapidly increase to 367MW, a rapid increase of 67MW. The total duration of this process is 15-30 seconds.

[0055] Phase Two of Rapid Load Increase (367MW→420MW) includes: After the transition phase and Phase One of Rapid Load Increase, the unit's generating load has increased to 367MW, and the boiler evaporation rate remains at 877.9t / h, achieving energy balance. The unit is operating in pure condensing mode. To achieve continuous and rapid load increase, according to... Figure 2 As shown in heat release method 4, all the low-temperature feedwater from the feedwater pump outlet is sent to the solid-state thermal storage device, heated, and then returned to the #0 high-pressure heater outlet. This avoids the extraction of steam from all high-pressure heaters, allowing the unit's power generation load to rapidly increase to 430MW, or 63MW. As the boiler gradually increases the main steam flow rate at its normal load-increasing rate, the low-temperature feedwater flow rate from the feedwater pump outlet to the solid-state thermal storage device is simultaneously reduced to zero, maintaining the unit's power generation load at 430MW. Specifically, the maximum low-temperature feedwater flow rate from the feedwater pump outlet to the solid-state thermal storage device is 877.9 t / h; the minimum main steam flow rate is 877.9 t / h, pressure is 13.97 MPa, and temperature is 605℃; the maximum main steam flow rate is 1031.7 t / h, pressure is 14.99 MPa, and temperature is 605℃. During this process, the flow rate of the low-temperature feedwater from the feedwater pump outlet to the solid-state thermal storage device reaches its maximum between 15 and 30 seconds. The total duration of the process is 263 seconds. The heat for heating the low-temperature feedwater comes from the heat stored during the transition phase, namely the heat in thermal storage module B.

[0056] Phase Three of the rapid load increase includes: After Phase Two, the unit's power generation load is maintained at 430MW, and the boiler evaporation rate has reached 1031.7t / h, achieving energy balance. The unit is operating in pure condensing mode. At this point, the goal of rapidly and continuously reducing the unit's power generation load from 420MW to 300MW, and then rapidly and continuously increasing it back to 430MW after several hours at 300MW has been achieved. However, the heat stored in solid thermal storage module A during the rapid load reduction phase has not been utilized, which will affect the unit's operation in the next rapid load change cycle. Therefore, in order to utilize the heat in thermal storage module A, and considering the unit's rapid load increase requirements, further steps can be taken based on Phase Two of the rapid load increase phase. Figure 2In heat release method 4, all the low-temperature feedwater from the feedwater pump outlet is sent to the solid-state thermal storage device, heated, and then returned to the #0 high-pressure heater outlet. This avoids the extraction of steam from all high-pressure heaters, allowing the unit's power generation load to rapidly increase to 508MW, or 78MW. As the boiler gradually increases the main steam flow rate at the normal set load increase rate, the low-temperature feedwater flow rate from the feedwater pump outlet to the solid-state thermal storage device is simultaneously reduced to zero, maintaining the unit's power generation load at 508MW. Specifically, the maximum low-temperature feedwater flow rate from the feedwater pump outlet to the solid-state thermal storage device is 1031.7 t / h; the minimum main steam flow rate is 1031.7 t / h, pressure is 14.99 MPa, and temperature is 605℃; the maximum main steam flow rate is 1229 t / h, pressure is 17.11 MPa, and temperature is 605℃. During this process, the flow rate of the low-temperature feedwater from the feedwater pump outlet to the solid-state thermal storage device reaches its maximum between 15 and 30 seconds. The total duration of the process is 330 seconds. The heat used to heat the low-temperature feedwater comes from a portion of the heat stored during the rapid load reduction phase, i.e., a portion of the heat in thermal storage module A.

[0057] Phase four of the rapid load increase includes: Phase three of the rapid load increase has already absorbed some of the heat stored in thermal storage module A during the rapid load decrease phase. In order to completely release the heat in thermal storage module A, and in accordance with the unit's rapid load increase requirements, based on Phase three of the rapid load increase, according to... Figure 2 As shown in heat release method 4, all the low-temperature feedwater from the feedwater pump outlet is sent to the solid-state thermal storage device, heated, and then returned to the #0 high-pressure heater outlet. This avoids the extraction of steam from all high-pressure heaters, allowing the unit's power generation load to rapidly increase to 604MW, a rapid increase of 96MW. As the boiler gradually increases the main steam flow rate at the normal set load increase rate, the low-temperature feedwater flow rate from the feedwater pump outlet to the solid-state thermal storage device is simultaneously reduced until zero, maintaining the unit's power generation load at 604MW. Specifically, the maximum low-temperature feedwater flow rate from the feedwater pump outlet to the solid-state thermal storage device is 1229t / h; the minimum main steam flow rate is 1229t / h, pressure is 17.11MPa, and temperature is 605℃; the maximum main steam flow rate is 1485t / h, pressure is 20.44MPa, and temperature is 605℃. During this process, the flow rate of the low-temperature feedwater from the feedwater pump outlet to the solid-state thermal storage device reaches its maximum between 15 and 30 seconds. The total duration of the process is 345 seconds. The heat used to heat the low-temperature feedwater comes from the remaining heat stored during the rapid load reduction phase, i.e., the remaining heat in thermal storage module A.

[0058] This invention provides a rapid frequency regulation system for thermal power units based on solid-state thermal energy storage devices. In this embodiment, the solid-state thermal energy storage device is selectively coupled to any two target high-pressure heaters in the high-pressure heater group via any part of a fluid connection network. Through the model prediction and control unit, the heat storage or release ratio and flow distribution are dynamically optimized, and the switching of the fluid connection network and feedwater flow are controlled based on the optimization results. This allows for heating or cooling of the unit's feedwater through the corresponding solid-state thermal energy storage device, thereby regulating the unit's power generation load. Through deep integration of the solid-state thermal energy storage unit and the regenerative system, rapid storage and release of thermal energy are achieved, significantly shortening the unit's response time to load commands, reducing coal consumption and wear during load changes, and ensuring the stability of key parameters such as main steam temperature and pressure. This greatly improves the overall efficiency and performance of thermal power units participating in rapid frequency regulation of the power grid.

[0059] Furthermore, as a response to the above Figure 1 The implementation of the method shown in this embodiment of the invention provides a method for rapid frequency regulation of thermal power units based on solid-state thermal storage devices, such as... Figure 3 As shown, the method includes: 201. Selectively couple the solid-state thermal storage device to any two target high-pressure heaters in the high-pressure heater group via any of the fluid connection networks.

[0060] 202. Through the model prediction control unit, the heat storage or heat release ratio and flow distribution are dynamically optimized, and the switching of the fluid connection network and the water supply flow are controlled according to the optimization results, so as to heat or cool the unit's water supply through the corresponding solid-state heat storage device and adjust the unit's power generation load.

[0061] This invention provides a method for rapid frequency regulation of thermal power units based on solid-state thermal energy storage devices. In this embodiment, the solid-state thermal energy storage device is selectively coupled to any two target high-pressure heaters in the high-pressure heater group via any part of a fluid connection network. Through the model prediction and control unit, the ratio of thermal energy storage or release and the flow distribution are dynamically optimized. Based on the optimization results, the switching of the fluid connection network and the feedwater flow are controlled to heat or cool the unit's feedwater through the corresponding solid-state thermal energy storage device, thereby regulating the unit's power generation load. Through deep integration of the solid-state thermal energy storage unit and the regenerative system, rapid storage and release of thermal energy are achieved, significantly shortening the unit's response time to load commands, reducing coal consumption and wear during load changes, and ensuring the stability of key parameters such as main steam temperature and pressure. This greatly improves the overall efficiency and performance of thermal power units participating in rapid frequency regulation of the power grid.

[0062] Furthermore, the preset connection method includes multiple heat storage connection methods and multiple heat release connection methods; the method further includes: Through any of the aforementioned thermal storage connection methods, the high-temperature feedwater of the high-pressure heater is cooled by the solid thermal storage device and then led to the inlet of the low-pressure heater to reduce the power generation load of the turbine. Through any of the aforementioned heat-exothermic connection methods, the low-temperature feedwater from the feedwater pump outlet or the low-pressure-level high-pressure heater is heated by the solid-state heat storage device and then led to the outlet or inlet of the high-pressure-level high-pressure heater to increase the power generation load of the turbine.

[0063] Furthermore, the preset connection method includes multiple heat storage connection methods with different connection spans, and multiple heat release connection methods with different connection spans; each heat storage connection method with different connection spans corresponds to a different load reduction range, and each heat release connection method with different connection spans corresponds to a different load increase range; the number of heat storage connection methods and heat release connection methods is the same.

[0064] Furthermore, the method also includes: determining the frequency modulation type and load adjustment parameters based on the received frequency modulation command; Based on the frequency regulation type, the load adjustment parameters, and the real-time operating parameters of the unit, the target connection method and the target thermal storage device are determined from multiple preset connection methods; The fluid connection network is switched to the target connection mode, and the water supply flow is controlled with a first flow rate to heat or cool the water supply through the target thermal storage device, thereby responding to the frequency modulation command.

[0065] Furthermore, the method also includes: When the frequency regulation type is a significant load reduction and peak shaving, one of the thermal storage connection methods is determined as the target connection method, and the idle or matching thermal storage device is taken as the target thermal storage device. When the frequency regulation type is a large-scale load increase and peak shaving, one of the heat release connection methods is determined as the target connection method, and the heat storage device used in the previous load reduction process is taken as the target heat storage device.

[0066] Furthermore, the method further includes: when the frequency regulation type is small-amplitude bidirectional AGC frequency regulation, if the load adjustment parameter is load reduction, then one of the thermal storage connection methods is determined as the target connection method, and the idle or matching thermal storage device is taken as the target thermal storage device; if the load adjustment parameter is load increase, then one of the heat release connection methods is determined as the target connection method, and the thermal storage device used in the previous load reduction process is taken as the target thermal storage device.

[0067] Furthermore, the thermal storage connection method includes a first thermal storage connection method to a fifth thermal storage connection method, wherein the number of high-pressure heaters connected to each thermal storage connection method increases sequentially, and the corresponding load adjustment range increases sequentially; the heat release connection method includes a first heat release connection method to a fifth heat release connection method, wherein the number of high-pressure heaters connected to each heat release connection method increases sequentially, and the corresponding load adjustment range increases sequentially; the method further includes: in the process of determining the target connection method from the thermal storage connection methods, determining the target thermal storage connection method from the five thermal storage connection methods based on the range matched by the load adjustment range in the load adjustment parameters; In the process of determining the target connection method from the heat release connection methods, the target heat release connection method is determined from five heat release connection methods based on the range of the load adjustment amplitude matched in the load adjustment parameters. Among them, for heat storage and heat release connection methods used in pairs to respond to the same load adjustment range, the connection span of the target heat release connection method is greater than the connection span of the target heat storage connection method paired with it.

[0068] Furthermore, the method also includes: during the execution of the thermal storage operation with the frequency regulation type of large-scale load increase and peak shaving, cutting off the transition connection mode to cause the unit's power generation load to increase in the first step. After the first step increase, the fluid connection network is switched to the target heat release connection mode that matches the load adjustment range, so that all the low temperature feedwater at the feedwater pump outlet flows through the transition heat storage device and is sent to the outlet of the high pressure heater group or the boiler inlet. At the same time, the boiler increases the main steam flow rate according to the allowable load increase rate, so that the unit's power generation load generates a second step increase and then continues to increase until the heat stored in the transition heat storage device is completely released. After the second step increase, the target heat release connection method is maintained, and all the low-temperature feedwater at the outlet of the feedwater pump flows through the target heat storage device for heating and then is sent out. At the same time, the boiler continues to increase the main steam flow, so that the unit's power generation load will generate a third step increase. After the third step increase, the target heat release connection is maintained, and all the low-temperature feedwater at the outlet of the feedwater pump flows through the target heat storage device for heating before being sent out. At the same time, the boiler continues to increase the main steam flow to the target value, causing the unit's power generation load to generate a fourth step increase and then continue to increase until the remaining heat stored in the target heat storage device is completely released and the unit load reaches the target high load.

[0069] It is obvious to those skilled in the art that the modules or steps of the present invention described above can be implemented using general computing methods. They can be centralized on a single computing method or distributed across a network of multiple computing methods. Optionally, they can be implemented using program code executable by the computing methods, thereby storing them in a storage method for execution by the computing methods. In some cases, the steps shown or described can be performed in a different order than those presented here, or they can be fabricated as separate integrated circuit modules, or multiple modules or steps can be fabricated as a single integrated circuit module. Thus, the present invention is not limited to any particular hardware and software combination.

[0070] The above description is merely a preferred embodiment of the present invention and is not intended to limit the invention. Various modifications and variations can be made to the present invention by those skilled in the art. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the scope of protection of the present invention.

Claims

1. A fast frequency modulation system for a thermal power generating unit based on a solid-state heat storage device, characterized in that, include: High-pressure heater assembly, fluid connection network, model prediction control unit and at least one solid-state thermal storage device; The high-pressure heater group includes multiple high-pressure heaters connected in sequence according to pressure level. The high-pressure side high-pressure heater is connected to the main feedwater inlet, and the low-pressure side high-pressure heater is connected to the feedwater pump inlet. The feedwater pump is used to inject the feedwater after it has passed through the high-pressure heater group and the solid thermal storage device into the boiler. The fluid connection network includes multiple switchable preset connection methods, any of which is used to selectively couple the solid thermal storage device to any two target high-pressure heaters in the high-pressure heater group; The model prediction and control unit is used to dynamically optimize the ratio and flow distribution of heat storage or heat release, and control the switching of the fluid connection network and the water supply flow based on the optimization results, so as to heat or cool the unit's water supply through the corresponding solid-state heat storage device and adjust the unit's power generation load.

2. The system of claim 1, wherein, The preset connection methods include multiple heat storage connection methods and multiple heat release connection methods; Any of the aforementioned thermal storage connection methods is used to lead the high-temperature feedwater from the high-pressure heater to the inlet of the low-pressure heater after cooling by the solid thermal storage device, thereby reducing the power generation load of the turbine. Any of the aforementioned heat-dissipating connection methods is used to heat the low-temperature feedwater from the feedwater pump outlet or the low-pressure-level high-pressure heater via the solid-state heat storage device, and then lead it to the outlet or inlet of the high-pressure-level high-pressure heater to increase the power generation load of the turbine.

3. The system of claim 1, wherein, The preset connection methods include multiple heat storage connection methods with different connection spans, and multiple heat release connection methods with different connection spans; Different connection spans for thermal storage have different load reduction ranges, and different connection spans for heat release have different load increase ranges. The number of heat storage connection methods and heat release connection methods is the same.

4. The system of claim 1, wherein, The model prediction control unit is specifically used for: Based on the received frequency modulation command, determine the frequency modulation type and load adjustment parameters; Based on the frequency regulation type, the load adjustment parameters, and the real-time operating parameters of the unit, the target connection method and the target thermal storage device are determined from multiple preset connection methods; The fluid connection network is switched to the target connection mode, and the water supply flow is controlled with a first flow rate to heat or cool the water supply through the target thermal storage device, thereby responding to the frequency modulation command.

5. The system of claim 4, wherein, The model prediction control unit is specifically used for: When the frequency regulation type is a significant load reduction and peak shaving, one of the thermal storage connection methods is determined as the target connection method, and the idle or matching thermal storage device is taken as the target thermal storage device. When the frequency regulation type is a large-scale load increase and peak shaving, one of the heat release connection methods is determined as the target connection method, and the heat storage device used in the previous load reduction process is taken as the target heat storage device.

6. The system of claim 5, wherein, The model prediction control unit is specifically used for: When the frequency regulation type is small-amplitude bidirectional AGC frequency regulation, if the load adjustment parameter is load reduction, then one of the thermal storage connection methods will be determined as the target connection method, and the idle or matching thermal storage device will be used as the target thermal storage device. If the load adjustment parameter is to increase the load, then one of the heat release connection methods will be determined as the target connection method, and the heat storage device used in the previous load reduction process will be used as the target heat storage device.

7. The system of claim 5 or 6, wherein, The heat storage connection method includes the first heat storage connection method to the fifth heat storage connection method, and the number of high-pressure heaters connected to each heat storage connection method increases sequentially, and the corresponding load adjustment range increases sequentially; the heat release connection method includes the first heat release connection method to the fifth heat release connection method, and the number of high-pressure heaters connected to each heat release connection method increases sequentially, and the corresponding load adjustment range increases sequentially. The model prediction control unit is specifically used for: In the process of determining the target connection method from the thermal storage connection methods, the target thermal storage connection method is determined from five thermal storage connection methods based on the range of load adjustment amplitude matched in the load adjustment parameters. In the process of determining the target connection method from the heat release connection methods, the target heat release connection method is determined from five heat release connection methods based on the range of the load adjustment amplitude matched in the load adjustment parameters. Among them, for heat storage and heat release connection methods used in pairs to respond to the same load adjustment range, the connection span of the target heat release connection method is greater than the connection span of the target heat storage connection method paired with it.

8. The system of claim 1, wherein, The model prediction control unit is specifically used for: During the low-load stable combustion phase of the unit in the thermal storage operation process where the frequency regulation type is large-scale load reduction and peak shaving, the target thermal storage connection mode is maintained, and the target thermal storage device is switched to a transitional thermal storage device. The feedwater flow rate is controlled by a second flow rate, and the feedwater is cooled by the transitional thermal storage device, wherein the second flow rate is less than the first flow rate when the target thermal storage device performs the cooling operation.

9. The system of claim 8, wherein, The model prediction control unit is specifically used for: During the execution of the thermal storage operation with the frequency regulation type of large-scale load increase and peak shaving, the transition connection is cut off, causing the unit's power generation load to increase in the first step. After the first step increase, the fluid connection network is switched to the target heat release connection mode that matches the load adjustment range, so that all the low temperature feedwater at the feedwater pump outlet flows through the transition heat storage device and is sent to the outlet of the high pressure heater group or the boiler inlet. At the same time, the boiler increases the main steam flow rate according to the allowable load increase rate, so that the unit's power generation load generates a second step increase and then continues to increase until the heat stored in the transition heat storage device is completely released. After the second step increase, the target heat release connection method is maintained, and all the low-temperature feedwater at the outlet of the feedwater pump flows through the target heat storage device for heating and then is sent out. At the same time, the boiler continues to increase the main steam flow, so that the unit's power generation load will generate a third step increase. After the third step increase, the target heat release connection is maintained, and all the low-temperature feedwater at the outlet of the feedwater pump flows through the target heat storage device for heating before being sent out. At the same time, the boiler continues to increase the main steam flow to the target value, causing the unit's power generation load to generate a fourth step increase and then continue to increase until the remaining heat stored in the target heat storage device is completely released and the unit load reaches the target high load.

10. A method for fast frequency regulation of a thermal power unit based on a solid-state heat storage device, characterized in that, The method is applied to a rapid frequency regulation system for thermal power units based on solid-state thermal storage devices as described in any one of claims 1-9. The system includes a high-pressure heater group, a fluid connection network, a model prediction control unit, and at least one solid-state thermal storage device. The high-pressure heater group includes multiple high-pressure heaters connected in sequence according to pressure levels. The high-pressure side heater is connected to the main feedwater inlet, and the low-pressure side heater is connected to the feedwater pump inlet. The feedwater pump is used to inject feedwater, after being processed by the high-pressure heater group and the solid-state thermal storage device, into the boiler. The fluid connection network includes multiple switchable preset connection modes. The method includes: The solid-state thermal storage device can be selectively coupled to any two target high-pressure heaters in the high-pressure heater group via any of the fluid connection networks; The model prediction control unit dynamically optimizes the ratio and flow distribution of heat storage or release, and controls the switching of the fluid connection network and the water supply flow based on the optimization results, so as to heat or cool the unit's feedwater through the corresponding solid-state thermal storage device and regulate the unit's power generation load.

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