Frequency modulation system of fused salt energy storage coupling thermal power generating unit

Abstract

The invention discloses a frequency modulation system of a fused salt energy storage coupling thermal power generating unit, belongs to the technical field of frequency modulation of power systems, and aims to solve the problems of low frequency modulation response speed, low energy storage efficiency and insufficient system coordination of the conventional thermal power generating unit. The system comprises a fused salt energy storage subsystem, a thermal power generating unit main system, a coupling heat exchange device, a power grid frequency monitoring module and a frequency modulation coordination control system, wherein the fused salt energy storage subsystem realizes efficient heat energy storage and release through a layered fused salt storage tank, a fused salt circulating pump, a heat exchanger and an auxiliary electric heating device; the thermal power generating unit main system is responsible for conventional power generation; the coupling heat exchange device injects fused salt heat energy into the main steam pipeline, and the steam enthalpy value is increased; the power grid frequency monitoring module collects frequency data in real time and calculates deviation; the frequency modulation coordination control system dynamically adjusts the fused salt flow and the operation mode through a fuzzy self-tuning PID unit, a heat exchange optimization distribution unit and a state judgment module, and three modes of quick response, combined frequency modulation and conventional stability are achieved.

Description

Technical Field

[0001] This invention relates to the field of power system frequency regulation technology, specifically a frequency regulation system for molten salt energy storage coupled to thermal power units. Background Technology

[0002] With the transformation of the global energy structure and the continuous increase in the proportion of renewable energy, the frequency stability of the power grid faces increasingly severe challenges. Traditional thermal power units, as the main support for grid frequency regulation, are limited in response speed and regulation capacity by the inertia of the coal combustion process and the adjustment range of mechanical equipment. Especially when facing sudden load changes or fluctuations in renewable energy output (such as wind and solar power), they struggle to adapt quickly, leading to increased frequency deviations and affecting the safe operation of the power grid. Furthermore, existing frequency regulation technologies largely rely on deep peak shaving by thermal power units or auxiliary energy storage devices (such as battery storage). However, battery storage suffers from high costs, limited lifespan, and environmental impacts, making it difficult to meet the needs of large-scale, long-term frequency regulation.

[0003] Molten salt energy storage technology has been widely used in solar thermal power generation due to its high thermal density, long lifespan, and low operating costs. However, existing molten salt energy storage systems are mainly used for thermal energy storage and release and have not been effectively integrated into the frequency regulation system of thermal power units, resulting in their potential not being fully utilized. There is limited research on the coupling of traditional thermal power units and molten salt energy storage, especially lacking coordinated control strategies for real-time grid frequency regulation, which limits the system's application efficiency and economy under dynamic loads.

[0004] To address the aforementioned problems, there is an urgent need to develop a frequency regulation system that couples molten salt energy storage to thermal power units. This system would utilize the high-efficiency thermal storage characteristics of molten salt to quickly respond to frequency deviations, while simultaneously combining this with the steady-state power output capability of the thermal power units to achieve efficient and economical grid frequency regulation. This invention aims to overcome the shortcomings of existing technologies, such as slow response speed, low energy storage efficiency, and insufficient system coordination, providing a new technical solution for stable grid operation. Summary of the Invention

[0005] The purpose of this invention is to provide a frequency regulation system for molten salt energy storage coupled thermal power units to solve the problems mentioned in the background art.

[0006] To achieve the above objectives, the present invention provides the following technical solution: A frequency regulation system for a molten salt energy storage coupled thermal power unit includes: Molten salt energy storage subsystem and main system of thermal power unit; Conventional control modules include the combustion control system and the turbine regulation system, which are used to regulate the unit's conventional load operating status. Coupled heat exchange device: installed in the main steam pipeline, used to receive molten salt heat energy output from the molten salt heat exchanger, transfer the heat to the boiler steam, increase the steam enthalpy value, and realize the effective injection of external heat source; Power grid frequency monitoring module: used to monitor the current power grid frequency value in real time. and with the set rated frequency Compare and obtain frequency deviation This provides real-time data for frequency modulation control; Frequency modulation coordinated control system, including: Fuzzy self-tuning PID unit: calculates the required target heat transfer power based on the frequency deviation. ; Heat exchange optimization distribution unit: Determines the required molten salt flow rate based on molten salt characteristics and heat exchange efficiency. ; Status judgment module: dynamically switches the frequency modulation mode based on the degree of frequency change; All control commands are transmitted to relevant subsystems through the industrial control network, enabling dynamic linkage and load regulation between the thermal power main system and the molten salt energy storage subsystem.

[0007] As a preferred embodiment of the present invention, the molten salt energy storage subsystem includes: Molten salt storage tank: Used to store high-temperature molten salt. The tank body is designed with a layered structure to distinguish between high-temperature, medium-temperature and low-temperature zones, and is equipped with a temperature monitoring device. Molten salt circulation pump: Its inlet is connected to the bottom outlet of the molten salt storage tank through an insulated pipe, and it is used to extract high-temperature molten salt from the storage tank; Molten salt heat exchanger: Its inlet is connected to the outlet of the molten salt circulation pump, and the outlet is connected to the middle or top of the molten salt storage tank through a return pipe to realize the return of molten salt after heat exchange; Auxiliary electric heating device: installed in the molten salt pipeline, mainly used to maintain or increase the molten salt temperature to meet the needs of rapid frequency adjustment; Temperature control module: works in conjunction with molten salt circulation pump, auxiliary electric heating device and layered structure of storage tank to control molten salt flow and temperature, so as to ensure stable operation of the system; The main system of a thermal power unit includes: Boiler: Used to generate high-temperature, high-pressure steam; Main steam pipe: connects the boiler and the steam turbine, and steam enters the steam turbine through this path; Steam turbine: Used to convert steam energy into mechanical energy, its main shaft is connected to a generator; Generator: Converts the mechanical energy output of a steam turbine into electrical energy.

[0008] As a preferred technical solution of the present invention, the power grid frequency deviation The calculation method for the rate of change is as follows: ; ; in, This is the system's rated reference frequency, typically 50Hz. This is the currently collected power grid frequency value. The continuous sampling interval is expressed in seconds.

[0009] As a preferred technical solution of the present invention, the fuzzy self-tuning PID control unit outputs the target heat transfer power through the following formula. : ; in, , , The proportional, integral, and derivative parameters for fuzzy logic are adaptively corrected based on the absolute value of frequency offset and fluctuation trend. This is the instantaneous thermal power that the molten salt heat exchanger needs to output in order to achieve stable frequency return; The target heat exchange power With molten salt flow rate The following thermodynamic relationship exists between them: ; in, This refers to the density of molten salt, expressed in kg / m³. 3 , This refers to the specific heat capacity of molten salt, expressed in J / kg·K. This refers to the molten salt flow rate, in meters (m³). 3 / s, , For the temperature difference between the inlet and outlet of the molten salt heat exchanger, and The temperature data is obtained from temperature sensors, which are located at the inlet and outlet of the molten salt heat exchanger.

[0010] As a preferred technical solution of the present invention, the increase in turbine power resulting from the increase in steam enthalpy is... This can be obtained through the following conversion: ; in, To determine the overall efficiency of the heat exchange-steam-electricity conversion, factors such as pipe loss and heat transfer efficiency should be considered. Enthalpy value per unit of steam; The additional power output is measured in W.

[0011] As a preferred embodiment of the present invention, the heat exchange optimization distribution unit calculates the optimal molten salt flow rate using the following objective function. ,Right now: ; in, , , For each adjustment objective, the weighting factors are... The current molten salt temperature, For the desired molten salt temperature, the first term is the main target for frequency regulation, the second term limits sudden changes in pump speed, and the third term ensures heat transfer stability.

[0012] As a preferred embodiment of the present invention, the molten salt storage tank is provided with three temperature zones inside: High-temperature zone (T>550℃): Connect to the frequency regulation emergency output and prioritize supply for high-load response; Medium temperature zone (350℃≤T≤550℃): Conventional circulation zone, used for stable heating; Low temperature zone (T<350℃): Backup buffer zone, only activated when the system is in low temperature standby or under extreme conditions; The temperature control module adjusts the molten salt extraction layer based on real-time temperature data to maximize the controllability and efficiency of the heat source.

[0013] As a preferred technical solution of the present invention, the power grid frequency signal After being processed by the following exponentially weighted moving average filter: ; in, For the filter sensitivity coefficient, To smooth the frequency signal after processing and avoid misjudging short-term fluctuations.

[0014] As a preferred technical solution of the present invention, the frequency modulation coordination control system has three operating modes: Fast Response Mode: When At that time, the system triggers a rapid molten salt heating response; Joint FM mode: When At that time, the thermal power plant and the thermal storage system work together; Normal stable mode: when At the same time, maintain the normal power output of thermal power plants and keep energy storage on standby.

[0015] As a preferred technical solution of the present invention, the frequency modulation coordination control system is interconnected with the plant-level DCS system and dispatch center via industrial Ethernet, and supports: Data on grid frequency, electrical power, heat exchange power, molten salt temperature, and flow rate are uploaded. Remote issuance of control commands and policy modification; Supports standard communication protocols such as IEC61850 and Modbus-TCP; The system log supports redundant local storage and cloud backup.

[0016] Compared with the prior art, the beneficial effects of the present invention are: 1. The molten salt energy storage coupled thermal power unit frequency regulation system of the present invention significantly improves the response speed and stability of power grid frequency regulation; through the rapid heat injection of the molten salt energy storage subsystem, the system can quickly enter the fast response mode when the power grid frequency deviation exceeds 0.2Hz, and use the high heat storage density characteristics of molten salt to provide additional heat power in a short time. Combined with the steady-state output of thermal power unit, it effectively shortens the frequency recovery time and meets the power grid's demand for rapid frequency regulation. 2. The system of the present invention achieves precise regulation of molten salt flow and temperature through the intelligent control strategy of fuzzy self-tuning PID unit and heat exchange optimization distribution unit, and optimizes heat distribution efficiency; the layered molten salt storage tank design (high temperature zone, medium temperature zone, low temperature zone) combined with the dynamic adjustment of temperature control module ensures the stability of heat source and the economy of system operation, reduces energy loss, and improves the overall economic benefits of frequency regulation. 3. The system of this invention interconnects with the plant-level DCS system and dispatch center via industrial Ethernet, supports real-time data uploading and remote command issuance, and adopts the IEC61850 and Modbus-TCP standard protocols to ensure the efficiency and reliability of control; redundant storage of logs and cloud backup further enhance the traceability and security of the system, providing strong support for the intelligent management and stable operation of the power grid. Attached Figure Description

[0017] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the accompanying drawings used in the description of the embodiments of the present invention or the prior art will be briefly introduced and explained below. Obviously, the accompanying drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0018] Figure 1 This is a system block diagram of a frequency regulation system for a molten salt energy storage coupled thermal power unit according to the present invention; Figure 2 This is a logic block diagram of the frequency regulation coordination control system of the frequency regulation system of the molten salt energy storage coupled thermal power unit of the present invention. Detailed Implementation

[0019] The following will be based on embodiments of the present invention. Figures 1-2The technical solutions in the embodiments of the present invention will be clearly and completely described below. Obviously, the embodiments described below are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the scope of protection of the present invention. In order to provide a clearer explanation and description of the technical solutions and implementation methods of the present invention, the following describes specific embodiments that implement the preferred technical solutions of the present invention.

[0020] The present invention provides a frequency regulation system for molten salt energy storage coupled with thermal power units. Its core lies in achieving efficient dynamic regulation of the power grid frequency through the coordinated linkage between the molten salt energy storage subsystem and the main system of the thermal power unit. The following provides a systematic and logical description of the specific implementation of the system, covering the system structure, operation mechanism, calculation method and control strategy.

[0021] The system mainly consists of a molten salt energy storage subsystem, a thermal power unit main system, a coupled heat exchange device, a power grid frequency monitoring module, and a frequency regulation coordination control system. The molten salt energy storage subsystem includes a molten salt storage tank, a molten salt circulating pump, a molten salt heat exchanger, an auxiliary electric heating device, and a temperature control module.

[0022] The molten salt storage tank features a layered design, divided into a high-temperature zone (T > 550℃), a medium-temperature zone (350℃ < T ≤ 550℃), and a low-temperature zone (T < 350℃), respectively for emergency high-load response, conventional heating, and system backup buffer. Temperature monitoring devices are installed inside the tank to collect real-time molten salt temperature data for each zone. A molten salt circulation pump draws high-temperature molten salt from the bottom of the tank through insulated pipes and transports it to a molten salt heat exchanger for heat exchange. After heat exchange, the molten salt returns to the middle or top of the tank through a return pipe.

[0023] An auxiliary electric heating device is installed in the molten salt pipeline to maintain or increase the molten salt temperature when the frequency needs to be adjusted rapidly.

[0024] The temperature control module works in conjunction with the molten salt circulation pump, heating device, and layered structure of the storage tank to dynamically adjust the molten salt flow rate and extraction layer based on real-time temperature data, thereby ensuring the stability and efficiency of the heat source. The main system of the thermal power unit consists of a boiler, main steam pipeline, steam turbine, and generator, and is responsible for conventional power generation tasks.

[0025] The boiler generates high-temperature, high-pressure steam, which is fed into the turbine through the main steam pipeline. The turbine converts the steam energy into mechanical energy and drives the generator to output electrical energy. The conventional control module maintains the unit's normal load operation through the combustion control system and the turbine regulation system. A coupled heat exchange device installed in the main steam pipeline receives the molten salt heat energy output from the molten salt heat exchanger and transfers the heat to the boiler steam, increasing the steam enthalpy value. This achieves effective injection of external heat sources and enhances frequency regulation response capability. The power grid frequency monitoring module is responsible for real-time acquisition of the current power grid frequency value. and with the set rated frequency Compare the data and calculate the frequency deviation and rate of change.

[0026] The frequency deviation formula is: ; The formula for the rate of change of frequency is: ; in, Sampling interval (unit: seconds). To reduce short-term fluctuation interference, the frequency signal is processed by exponentially weighted moving average filtering: ; in, For the filter sensitivity coefficient, To smooth the frequency signal after processing and avoid misjudging short-term fluctuations.

[0027] These parameters provide real-time and accurate feedback for the frequency modulation coordinated control system.

[0028] The frequency modulation and coordination control system serves as the core of the system, comprising a fuzzy self-tuning PID unit, a heat exchange optimization allocation unit, and a state judgment module.

[0029] The fuzzy self-tuning PID unit is based on the frequency deviation. and rate of change The target thermal power is calculated by adaptively adjusting the proportional, integral, and derivative parameters: ; in, , , The parameters for real-time adjustment of fuzzy logic are dynamically corrected based on the absolute value and fluctuation trend of the frequency deviation. This refers to the instantaneous thermal power output by the molten salt heat exchanger.

[0030] The thermodynamic relationship between heat exchange power and molten salt flow rate is as follows: Where, is the density of the molten salt (unit: kg / m³), Specific heat capacity of molten salt (unit: J / kg·K), Molten salt flow rate (unit: m³ / s), The temperature difference between the inlet and outlet of the heat exchanger (unit: K) is obtained by temperature sensors installed at the inlet and outlet of the heat exchanger.

[0031] The heat exchange optimization distribution unit optimizes the molten salt flow rate using an objective function: ; in, , , As a weighting factor, The current molten salt temperature, To achieve the desired temperature, the first term optimizes frequency regulation, the second term limits sudden changes in pump speed, and the third term ensures heat exchange stability.

[0032] The status judgment module dynamically switches the operating mode based on the frequency deviation: when When it enters the fast response mode, it triggers molten salt heating; when When it enters the joint frequency regulation mode, thermal power and thermal storage work together; when When the system enters a normal stable mode, it maintains the normal output of thermal power plants, and energy storage is on standby. The increase in steam power is calculated using the following formula: ; in, To determine the overall efficiency of the heat exchange-steam-electricity conversion (considering factors such as pipe losses and heat transfer efficiency), The value is the enthalpy of steam per unit (unit: J / kg). The additional power output (unit: W) reflects the contribution of molten salt energy storage to frequency regulation.

[0033] The system is interconnected with the plant-level DCS system and dispatch center via industrial Ethernet, supporting real-time uploading of data such as grid frequency, power, heat exchange power, molten salt temperature and flow rate, as well as remote issuance of control commands and policy correction. The communication protocol complies with IEC61850 and Modbus-TCP standards. The system logs adopt redundant local storage and cloud backup, ensuring data security and traceability.

[0034] Through the above design, this invention can respond quickly to grid frequency fluctuations, achieving efficient frequency regulation by utilizing the thermal inertia of molten salt energy storage and the steady-state output of thermal power units. The three-layer temperature zone structure of the molten salt storage tank and the precise adjustment of the temperature control module ensure the controllability and stability of the heat source; the intelligent algorithms of the fuzzy self-tuning PID unit and the optimized allocation unit improve the system's adaptability to frequency deviations; and the heat injection of the coupled heat exchange device enhances the frequency regulation capability. The overall system exhibits excellent dynamic response and stability in real grid scenarios, demonstrating significant engineering application value.

[0035] The following is a detailed explanation using several examples: Example 1: Frequency regulation process in fast response mode; Scenario description: Assume the current time is May 12, 2025, a sudden increase in grid load causes the grid frequency to drop from 50Hz to 49.7Hz, frequency deviation. The triggering conditions for the fast response mode are met. The system needs to rapidly inject thermal power to stabilize the frequency.

[0036] 1. Implementation Process: Frequency Monitoring and Mode Switching: The power grid frequency monitoring module collects frequency data in real time and calculates the frequency deviation. ; The rate of change of frequency is calculated using the formula: ; Assuming sampling interval Frequency deviation at the previous moment ,but: ; The status judgment module detected Switch to fast response mode and prioritize the activation of the molten salt energy storage subsystem.

[0037] 2. Molten salt heat source preparation: The temperature control module reads the temperature data of the high-temperature zone (T > 550℃) of the molten salt storage tank, such as the current temperature. .

[0038] The auxiliary electric heating device is activated to maintain the molten salt temperature above 550°C, ensuring the availability of the heat source.

[0039] 3. Heat exchange power calculation: The fuzzy self-tuning PID unit calculates the heat exchange power based on... and rate of change Dynamically adjust parameters (assuming the fuzzy logic adaptive result is) , , ).

[0040] The formula for calculating the target heat exchange power is: ; Assume the integral term (Based on short-term integrals), substituting the parameters: ; 4. Flow Optimization and Allocation: Calculate the required molten salt flow rate based on thermodynamic relationships. The formula is: ; in, (Molten salt density) (Specific heat capacity of molten salt) (Assume the outlet temperature is 530℃).

[0041] Substitute into the calculation: ; The heat exchange optimization distribution unit optimizes the molten salt flow rate using an objective function, as shown in the formula: ; Set weighting factors , , Desired temperature Current temperature Flow rate of change The flow rate is relatively small, and after optimization, it remains at 0.344 L / s.

[0042] 5. Heat injection and power enhancement: The molten salt circulation pump extracts high-temperature molten salt at an optimized flow rate of 0.344 L / s, and the coupled heat exchange device transfers the heat to the main steam pipeline.

[0043] The formula for steam power increment is: ; in, (Heat exchange-steam-electricity conversion efficiency) (Vaporific value). Substitute into the calculation: ; 6. Feedback and Adjustment: The frequency signal is filtered. ; set up Frequency at the previous moment ,but: ; The monitoring module continuously updates the data, and the frequency modulation and coordination control system adjusts the heat exchange power according to the new deviation until the frequency is restored to 50Hz.

[0044] Results: By rapidly heating with molten salt, the system increased the frequency from 49.7Hz to 49.9Hz within 3 minutes, verifying the effectiveness of the fast response mode.

[0045] Example 2: Frequency modulation process in combined frequency modulation mode; Scenario description: The power grid load fluctuates relatively slowly, and the frequency drops from 50Hz to 49.85Hz. The conditions for joint frequency modulation mode are met. The system requires thermal power and molten salt energy storage to work together.

[0046] Implementation process: 1. Frequency Monitoring and Mode Switching: The power grid frequency monitoring module calculates: ; Rate of change: (Assume the deviation at the previous moment was 0.1Hz); The status judgment module switches to the joint frequency regulation mode and initiates the coordinated regulation of the thermal power main system and molten salt energy storage.

[0047] 2. Thermal power plant base regulation: The conventional control module increases the amount of coal burned in the boiler through the combustion control system, and the turbine regulation system optimizes the steam flow, thereby increasing the base output by approximately 300kW.

[0048] 3. Molten Salt Heat Source Supplementation: The temperature control module draws molten salt from the medium-temperature zone (T=400℃), and the auxiliary electric heating device raises the temperature to 450℃. The fuzzy self-tuning PID unit then... Adjust parameters , , Calculate the target heat transfer power: (Assume the integral term is 0.1).

[0049] 4. Flow optimization and allocation: Based on thermodynamic relationships: ; set up Substitute: ; The objective function optimizes traffic flow, let... , , This ensures a stable pump speed and near .

[0050] 5. Heat Injection and Power Boost: Molten salt enters the heat exchanger at a flow rate of 0.185 L / s. Calculate the additional output: ; The total output is 300kW (thermal power) + 68kW (molten salt) = 368kW.

[0051] 6. Feedback and Adjustment: Filtered Frequency: ; The system was continuously optimized until the frequency was restored to 50Hz.

[0052] Results: The combined frequency regulation mode increased the frequency from 49.85Hz to 49.98Hz within 8 minutes, demonstrating the synergistic advantages of thermal power and energy storage.

[0053] The contents not described in detail in this description are existing technologies known to those skilled in the art. Although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art can still modify the technical solutions described in the foregoing embodiments or make equivalent substitutions for some of the technical features. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the protection scope of the present invention.

Claims

1. A frequency regulation system for a molten salt energy storage coupled thermal power unit, characterized in that, include: Molten salt energy storage subsystem and main system of thermal power unit; Conventional control modules include the combustion control system and the turbine regulation system, which are used to regulate the unit's conventional load operating status. Coupled heat exchange device: installed in the main steam pipeline, used to receive molten salt heat energy output from the molten salt heat exchanger, transfer the heat to the boiler steam, increase the steam enthalpy value, and realize the effective injection of external heat source; Power grid frequency monitoring module: used to monitor the current power grid frequency value in real time. and with the set rated frequency Compare and obtain frequency deviation This provides real-time data for frequency modulation control; Frequency modulation coordinated control system, including: Fuzzy self-tuning PID unit: calculates the required target heat transfer power based on the frequency deviation. ; Heat exchange optimization distribution unit: Determines the required molten salt flow rate based on molten salt characteristics and heat exchange efficiency. ; Status judgment module: dynamically switches the frequency modulation mode based on the degree of frequency change; All control commands are transmitted to relevant subsystems through the industrial control network, enabling dynamic linkage and load regulation between the thermal power main system and the molten salt energy storage subsystem.

2. The frequency regulation system for a molten salt energy storage coupled thermal power unit according to claim 1, characterized in that, The molten salt energy storage subsystem includes: Molten salt storage tank: Used to store high-temperature molten salt. The tank body is designed with a layered structure to distinguish between high-temperature, medium-temperature and low-temperature zones, and is equipped with a temperature monitoring device. Molten salt circulation pump: Its inlet is connected to the bottom outlet of the molten salt storage tank through an insulated pipe, and it is used to extract high-temperature molten salt from the storage tank; Molten salt heat exchanger: Its inlet is connected to the outlet of the molten salt circulation pump, and the outlet is connected to the middle or top of the molten salt storage tank through a return pipe to realize the return of molten salt after heat exchange; Auxiliary electric heating device: installed in the molten salt pipeline, mainly used to maintain or increase the molten salt temperature to meet the needs of rapid frequency adjustment; Temperature control module: works in conjunction with molten salt circulation pump, auxiliary electric heating device and layered structure of storage tank to control molten salt flow and temperature, so as to ensure stable operation of the system; The main system of a thermal power unit includes: Boiler: Used to generate high-temperature, high-pressure steam; Main steam pipe: connects the boiler and the steam turbine, and steam enters the steam turbine through this path; Steam turbine: Used to convert steam energy into mechanical energy, its main shaft is connected to a generator; Generator: Converts the mechanical energy output of a steam turbine into electrical energy.

3. The frequency regulation system for a molten salt energy storage coupled thermal power unit according to claim 1, characterized in that, The power grid frequency deviation The calculation method for the rate of change is as follows: ； ； in, This is the system's rated reference frequency, typically 50Hz. This is the currently collected power grid frequency value. The continuous sampling interval is expressed in seconds.

4. The frequency regulation system for a molten salt energy storage coupled thermal power unit according to claim 1, characterized in that, The fuzzy self-tuning PID control unit outputs the target heat exchange power using the following formula. : ； in, , , The proportional, integral, and derivative parameters for fuzzy logic are adaptively corrected based on the absolute value of frequency offset and fluctuation trend. This is the instantaneous thermal power that the molten salt heat exchanger needs to output in order to achieve stable frequency return; The target heat exchange power With molten salt flow rate The following thermodynamic relationship exists between them: ； in, This refers to the density of molten salt, expressed in kg / m³. 3 , This refers to the specific heat capacity of molten salt, expressed in J / kg·K. This refers to the molten salt flow rate, in meters (m³). 3 / s, , For the temperature difference between the inlet and outlet of the molten salt heat exchanger, and The temperature data is obtained from temperature sensors, which are located at the inlet and outlet of the molten salt heat exchanger.

5. The frequency regulation system for a molten salt energy storage coupled thermal power unit according to claim 1, characterized in that, The increase in turbine power resulting from the increase in steam enthalpy This can be obtained through the following conversion: ； in, To determine the overall efficiency of the heat exchange-steam-electricity conversion, factors such as pipe loss and heat transfer efficiency should be considered. Enthalpy value per unit of steam; The additional power output is measured in W.

6. The frequency regulation system for a molten salt energy storage coupled thermal power unit according to claim 1, characterized in that, The heat exchange optimization allocation unit calculates the optimal molten salt flow rate using the following objective function. ,Right now: ； in, , , For each adjustment objective, the weighting factors are... The current molten salt temperature, For the desired molten salt temperature, the first term is the main target for frequency regulation, the second term limits sudden changes in pump speed, and the third term ensures heat transfer stability.

7. The frequency regulation system for a molten salt energy storage coupled thermal power unit according to claim 2, characterized in that, The molten salt storage tank has three temperature zones inside: High-temperature zone (T>550℃): Connect to the frequency regulation emergency output and prioritize supply for high-load response; Medium temperature zone (350℃≤T≤550℃): Conventional circulation zone, used for stable heating; Low temperature zone (T<350℃): Backup buffer zone, only activated when the system is in low temperature standby or under extreme conditions; The temperature control module adjusts the molten salt extraction layer based on real-time temperature data to maximize the controllability and efficiency of the heat source.

8. The frequency regulation system for a molten salt energy storage coupled thermal power unit according to claim 1, characterized in that, The power grid frequency signal After being processed by the following exponentially weighted moving average filter: ； in, For the filter sensitivity coefficient, To smooth the frequency signal after processing and avoid misjudging short-term fluctuations.

9. The frequency regulation system for a molten salt energy storage coupled thermal power unit according to claim 1, characterized in that, The frequency modulation coordination control system has three operating modes: Fast Response Mode: When At that time, the system triggers a rapid molten salt heating response; Joint FM mode: When At that time, the thermal power plant and the thermal storage system work together; Normal stable mode: when At the same time, maintain the normal power output of thermal power plants and keep energy storage on standby.

10. The frequency regulation system for a molten salt energy storage coupled thermal power unit according to claim 1, characterized in that, The frequency modulation coordination control system is interconnected with the plant-level DCS system and dispatch center via industrial Ethernet, supporting: Data on grid frequency, electrical power, heat exchange power, molten salt temperature, and flow rate are uploaded. Remote issuance of control commands and policy modification; Supports standard communication protocols such as IEC61850 and Modbus-TCP; The system log supports redundant local storage and cloud backup.

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