Safety control method and system for steam extraction energy storage and high-temperature fused salt energy storage

Abstract

The invention discloses a steam extraction energy storage high-temperature fused salt energy storage safety control method and system, and relates to the technical field of thermoelectricity. An electric stop valve and a regulating valve are additionally arranged on a connecting pipeline of a high-pressure cylinder exhaust pipe and a fused salt system, and the connecting pipeline is connected with a control system; monitoring temperature, flow and pressure data of the steam and the fused salt in real time; calculating system energy power and an energy fluctuation coefficient; a threshold value is set for hierarchical control, the adjusting valve is finely adjusted according to slight fluctuation, the adjusting valve is greatly adjusted according to the trend in moderate fluctuation, the electric stop valve and the adjusting valve are closed to the minimum opening degree in serious fluctuation, and gradual recovery is conducted after faults are removed; monitoring data are fed back after the valve acts, the calculation parameters are evaluated again, and the weight coefficient is adjusted. Compared with the prior art, the isolation time of the molten salt system and the host can be shortened to the millisecond level, energy is accurately controlled in real time, a feedback optimization mechanism is provided, and the operation stability and economic benefits are higher.

Description

Technical Field

[0001] The present invention relates to the technical field of thermoelectricity, and particularly to a safety control method and system for steam extraction energy storage high-temperature molten salt energy storage. Background Art

[0002] The load regulation ability of traditional thermal power units is limited. With the continuous increase of the peak-valley difference of the power grid, thermal power units need to have stronger peak regulation capabilities to meet the dynamic changes of power supply and demand. The "steam extraction energy storage" heat storage peak regulation flexibility transformation technology has been developed under such demands, and the high-temperature molten salt energy storage technology route has attracted much attention.

[0003] Taking a 600MW subcritical thermal power unit as an example, after being transformed by using the high-temperature molten salt energy storage technology, a steam extraction molten salt heat storage system including structures such as a low-temperature molten salt tank, a heat exchange platform, and a high-temperature molten salt tank is newly added. During the low valley period of the power grid, the surplus steam heat of the boiler is used to heat the molten salt and store it in the high-temperature molten salt tank, realizing the decoupling of the boiler and the generator set, enabling the unit to flexibly adjust the load, and making room for new energy power generation; during the peak period of the power grid, the stored heat is released again to heat the feed water to generate steam, increasing the peak shaving ability of the generator set.

[0004] However, there are still some problems to be solved urgently in the actual application of the existing technology. On the one hand, both the main steam inlet point of the heat storage system and the heat return point of the heat release system are located at the exhaust pipe of the high-pressure cylinder, and it currently takes 6 minutes for the two isolation gate valves set on this pipeline to close fully. In the event of an accident in the molten salt system, such a long closing time cannot isolate the molten salt system from the main engine in time, posing a great safety hazard, which may lead to the expansion of the accident, causing serious economic losses and safety accidents.

[0005] On the other hand, the existing technology is not precise enough in monitoring and controlling the energy of the system. During the energy storage and release process, there is a lack of real-time and accurate monitoring of the temperature, flow rate of steam and molten salt, and the system pressure, making it difficult to accurately calculate the system energy power and energy fluctuation conditions. This makes the system unable to adjust the operating state in a timely and effective manner in the face of complex working conditions, affecting the stability and efficiency of the system.

[0006] To sum up, although the steam extraction energy storage high-temperature molten salt energy storage technology has great potential in power peak regulation and energy storage, the defects of the existing technology limit its further development and application. It is urgent to develop a technology that can quickly isolate accidents, accurately control energy fluctuations, and ensure the safe and stable operation of the unit, which not only helps to improve the flexibility and reliability of thermal power units, but also provides strong support for the large-scale access of renewable energy, promoting the optimization and sustainable development of the energy structure. Summary of the Invention

[0007] The object of the present invention is to provide a safety control method and system for steam extraction and energy storage with high-temperature molten salt energy storage. The safety control method for steam extraction and energy storage with high-temperature molten salt energy storage realizes the safe and stable operation of the steam extraction and energy storage system with high-temperature molten salt energy storage by adding valves, collecting data to calculate energy power and fluctuation coefficients, controlling the valves in grades according to thresholds, and combining feedback optimization, so as to solve the above problems.

[0008] To achieve the above object, the present invention provides the following technical solutions:

[0009] A safety control method for steam extraction and energy storage with high-temperature molten salt energy storage, characterized by comprising the following steps:

[0010] S1: Add valves, specifically including adding an electric globe valve and a regulating valve on the connecting pipeline between the exhaust pipe of the high-pressure cylinder and the molten salt system, and connecting the electric globe valve and the regulating valve to a control system. Adding an electric globe valve and a regulating valve on the connecting pipeline between the exhaust pipe of the high-pressure cylinder and the molten salt system, and connecting the electric globe valve and the regulating valve to a control system are the basic hardware facilities for realizing safety control. The electric globe valve is mainly used to quickly cut off the flow of the medium in the pipeline in case of emergency, playing the role of isolating the system; the regulating valve is used to accurately adjust the flow rate of steam or molten salt to meet the operation requirements of the system under different working conditions. Through the control system, remote operation and automatic control of these two valves can be realized, improving the response speed and safety of the system.

[0011] S2: Data collection, including real-time monitoring of the temperature and flow data of steam and molten salt, and measurement of the pressure in the system; including a temperature sensor for real-time monitoring of the temperature of steam and molten salt, a pressure sensor for measuring the pressure in the system, and a flow sensor for obtaining the flow data of steam and molten salt.

[0012] S3: Calculate the system energy power, including the calculation of the energy power of steam and the calculation of the energy power of molten salt; the system energy power P is the sum of the energy power of steam and the energy power of molten salt, and its formula is:

[0013] P = P 蒸汽 + P 熔盐

[0014] wherein, P 蒸汽 is the energy power of steam, and P 熔盐 is the energy power of molten salt.

[0015] The calculation formula for the energy power of the steam is:

[0016] P 蒸汽 = h·q m

[0017] wherein, h is the specific enthalpy of steam, obtained by looking up the thermodynamic property chart of steam; q mis the mass flow rate of steam, which is obtained by multiplying the previous volume flow rate by the steam density.

[0018] The calculation formula for the molten salt energy power is

[0019] P 熔盐 = c p ·ρ·q v ·ΔT

[0020] where c p is the specific heat capacity at constant pressure of the molten salt; ρ is the density of the molten salt, which is obtained by referring to the temperature-density relationship curve of the molten salt; q v is the volume flow rate of the molten salt, which is measured by a flow measurement device; ΔT is the temperature change of the molten salt. By calculating the energy power of steam and molten salt, the energy distribution and changes within the system can be comprehensively understood.

[0021] S4: Calculate the energy fluctuation coefficient, comprehensively considering the amplitude, rate, and duration of the change in the system energy power; the energy fluctuation coefficient comprehensively considers the amplitude, rate, and duration of the change in the system energy power, and the calculation formula is as follows:

[0022]

[0023] where t is the current time, T is the set time window; P(i) represents the system energy power at time i; is the average energy power within the time interval [t - T, t], w1, w2, w3 are weight coefficients, and w1 + w2 + w3 = 1, respectively reflecting the influence of the deviation between the current energy power and the average power, the energy power change rate, and the energy power cumulative deviation on the fluctuation coefficient; Δt is the time interval between adjacent measurement times, T is the duration length for calculating the energy power cumulative deviation, and T < t. This formula comprehensively measures the energy fluctuation situation through three parts, reflects the deviation degree between the current energy power and the average power. The greater the deviation, the worse the stability of the system energy; reflects the change rate of the energy power. The faster the change rate, the greater the impact on the stability of the system; considers the cumulative deviation of the energy power over a period of time, more comprehensively reflecting the long-term trend of the system energy fluctuation. By calculating the energy fluctuation coefficient, the operating stability of the system can be more accurately evaluated.

[0024] S5: Energy fluctuation coefficient and valve coordinated control hierarchical strategy; Step S5 energy fluctuation coefficient and valve coordinated control hierarchical strategy includes setting the first threshold EFC1 and the second threshold EFC2, and setting the following levels according to the thresholds:

[0025] Slight fluctuations, i.e., 0 < EFC(t) ≤ EFC1. At this time, the control system sends a fine-tuning command to the regulating valve according to the specific value of the energy fluctuation coefficient. If EFC(t) is close to the upper limit EFC1 of slight fluctuations, the regulating valve will reduce the opening degree; if EFC(t) is close to the lower limit, the opening degree will be fine-tuned to maintain the flow stability, and the motorized globe valve remains fully open. If EFC is close to the upper limit EFC1 of slight fluctuations, it indicates that the energy fluctuation of the system has an increasing trend, and the regulating valve will reduce the opening degree to reduce the flow rate of steam or molten salt, thereby stabilizing the system energy. If EFC is close to the lower limit, the opening degree will be fine-tuned to maintain the flow stability, while the motorized globe valve remains fully open because the fluctuation of the system is small at this time and there is no need to cut off the pipeline.

[0026] Moderate fluctuations, i.e., EFC1 < EFC(t) ≤ EFC2. At this time, the control system issues a larger adjustment command to the regulating valve according to the energy fluctuation coefficient and the fluctuation trend. If the energy fluctuation of the system shows an upward trend, the regulating valve quickly reduces the opening degree; if the fluctuation shows a downward trend and is close to the normal range, the regulating valve moderately increases the opening degree, and the motorized globe valve remains fully open. If the energy fluctuation of the system shows an upward trend, it indicates that there is a risk of energy surplus, and the regulating valve quickly reduces the opening degree to prevent further energy accumulation; if the fluctuation shows a downward trend and is close to the normal range, the regulating valve moderately increases the opening degree to ensure the energy supply of the system. The motorized globe valve still remains fully open at this stage.

[0027] Severe fluctuations, i.e., EFC(t) > EFC2. At this time, the control system immediately issues a command to close the motorized globe valve, cut off the pipeline, prevent the flow of steam or molten salt, isolate the molten salt system from the high-pressure cylinder, and at the same time close the regulating valve to the minimum opening degree. After the system fault is eliminated and stabilized, according to the recovery of the energy fluctuation coefficient, first slowly open the regulating valve to conduct a tentative adjustment of the system. After the system is stable, further adjust the opening degree according to the energy fluctuation condition. If the energy fluctuation coefficient continues to be stable within the normal range, slowly open the motorized globe valve to restore the normal operation of the system. If the energy fluctuation coefficient continues to be stable within the normal range, slowly open the motorized globe valve to restore the normal operation of the system. This hierarchical control strategy can take corresponding measures according to different degrees of system energy fluctuations to ensure the safe and stable operation of the system.

[0028] S6: Feedback and optimization. Specifically, after the valve action, the sensor continuously monitors the operating parameters of the system and real-time feeds these data back to the control system; the control system compares and analyzes the feedback data with the set standard parameters, re-evaluates the calculation parameters of the energy fluctuation coefficient, and adjusts the weight coefficients w1, w2, w3.

[0029] A safety control system for an extraction steam energy storage high-temperature molten salt energy storage system, which includes a data acquisition module, a data processing module, a central control module, and a feedback and optimization module. The data acquisition module collects data at key positions of the system through various sensors; the data processing module performs data preprocessing, energy power calculation, and energy fluctuation coefficient calculation; the central control module receives the results of the data processing module, compares the thresholds and controls the valves, and analyzes the feedback data, adjusts the calculation parameters and control strategies; the data analysis unit of the feedback and optimization module analyzes the feedback data, and the strategy adjustment unit assists the central control module to optimize the parameters and strategies.

[0030] An electric stop valve, a regulating valve, and a control system are added to the connecting pipe between the exhaust pipe of the high-pressure cylinder and the molten salt system to provide a hardware basis for safety control. During operation, relevant data of steam and molten salt are collected in real time by temperature, pressure, and flow sensors. The energy power of steam and molten salt is calculated through specific formulas, and then the system energy power is obtained. Then, the energy fluctuation coefficient is calculated by combining the amplitude, rate, and duration of the change in the system energy power. According to the set first threshold EFC1 and second threshold EFC2, the energy fluctuation situation is classified. During slight fluctuations, the control system finely adjusts the opening of the regulating valve to maintain stable flow; during moderate fluctuations, the regulating valve is adjusted greatly according to the fluctuation trend; during severe fluctuations, the electric stop valve is immediately closed to cut off the pipeline, isolating the molten salt system from the high-pressure cylinder, and the regulating valve is also closed to the minimum opening. After the troubleshooting is stable, it is gradually restored. In addition, after the valve action, the sensors continuously monitor the system operation parameters and feedback them to the control system, compare and analyze them with the standard parameters, re-evaluate the calculation parameters of the energy fluctuation coefficient, and adjust the weight coefficient to achieve system feedback and optimization, ensuring the safe and stable operation of the entire extraction steam energy storage high-temperature molten salt energy storage system.

[0031] Compared with the prior art, the beneficial effects of the present invention are:

[0032] In the prior art, it takes 6 minutes to isolate the heat storage system from the main engine, while this technology adds a pneumatic quick shut-off valve, which can shorten the isolation time to the millisecond level. Once an accident occurs in the molten salt system, the pipeline can be quickly cut off to prevent the accident from spreading, greatly reducing the risk of damage to the unit caused by the accident and ensuring the safe and stable operation of the unit, which is incomparable to the prior art.

[0033] By real-time monitoring the temperature, flow, and pressure data of steam and molten salt, accurately calculating the system energy power and energy fluctuation coefficient, and performing hierarchical control according to the set thresholds. During slight fluctuations, the regulating valve is finely adjusted to maintain stable flow; during moderate fluctuations, it is adjusted greatly according to the trend; during severe fluctuations, it is cut off in time, realizing precise control of the system energy, avoiding damage to equipment caused by large energy fluctuations, and having higher operation stability compared with the prior art.

[0034] It has a feedback and optimization mechanism. After the valve operates, the sensor continuously monitors the operating parameters and feeds them back to the control system. The system compares the standard parameters, re-evaluates and calculates the parameters, and adjusts the weight coefficient. It can continuously optimize the control strategy according to the actual operating conditions, enabling the system to better adapt to various complex working conditions and maintain efficient and stable operation for a long time. The existing technology lacks this self-adaptive optimization ability.

[0035] Effectively prevent and promptly handle accidents in the molten salt system, reduce the frequency of equipment damage and failures, and lower the costs of equipment maintenance and replacement. The self-adaptive optimization function extends the service life of the equipment, further saves maintenance costs, and improves economic benefits, which is difficult to achieve with the existing technology.

[0036] Precise energy control and a fast response mechanism enable the steam extraction and energy storage high-temperature molten salt energy storage system to store and release energy more efficiently during power grid peak shaving. It can better absorb excess energy during off-peak periods and supplement it in a timely manner during peak periods, improving the peak shaving flexibility of thermal power units and optimizing the operation of the power grid. The adjustment accuracy and response speed of the existing technology are relatively weak in this regard. Brief Description of the Drawings

[0037] Figure 1 It is a flow chart of a safety control method for a steam extraction and energy storage high-temperature molten salt energy storage system of the present invention;

[0038] Figure 2 It is a working principle diagram of an embodiment of a safety control method for a steam extraction and energy storage high-temperature molten salt energy storage system of the present invention;

[0039] Figure 3 It is a schematic diagram of a newly added valve in an embodiment of a safety control method for a steam extraction and energy storage high-temperature molten salt energy storage system of the present invention. Specific Implementation Method

[0041] Next, the technical solutions in the embodiments of the present invention will be fully described in conjunction with the drawings in the embodiments of the present invention.

[0042] As Figures 1-3 shown, a safety control method for a steam extraction and energy storage high-temperature molten salt energy storage system is characterized by including the following steps:

[0043] S1: Add valves, including adding electric globe valves, regulating valves, and a control system;

[0044] S2: Data collection, continuously monitor the temperature and flow data of steam and molten salt in real time, and measure the pressure inside the system;

[0045] S3: Calculate the system energy power, including calculating the energy power of steam and the energy power of molten salt;

[0046] S4: Calculate the energy fluctuation coefficient, comprehensively considering the amplitude, rate, and duration of the change in the system energy power;

[0047] S5: Coordinated control hierarchical strategy of energy fluctuation coefficient and valve;

[0048] S6: Feedback and optimization.

[0049] In step S1, valves are added, specifically including adding an electric globe valve and a regulating valve on the connecting pipeline between the exhaust pipe of the high-pressure cylinder and the molten salt system, and connecting the control systems of the electric globe valve and the regulating valve.

[0050] In step S2, data collection includes using temperature sensors to monitor the temperature of steam and molten salt in real time, pressure sensors to measure the pressure inside the system, and flow sensors to obtain the flow rate data of steam and molten salt.

[0051] In step S3, calculating the system energy power includes calculating the energy power of steam and the energy power of molten salt. The system energy power P is the sum of the energy power of steam and the energy power of molten salt, and its formula is:

[0052] P = P 蒸汽 + P 熔盐

[0053] where, P 蒸汽 is the energy power of steam, and P 熔盐 is the energy power of molten salt.

[0054] The formula for calculating the energy power of the steam is:

[0055] P 蒸汽 = h·q m

[0056] where, h is the specific enthalpy of steam, obtained by referring to the thermodynamic property chart of steam; q m is the mass flow rate of steam, obtained by multiplying the previous volume flow rate by the steam density.

[0057] The formula for calculating the energy power of the molten salt is

[0058] P 熔盐 = c p ·ρ·q v ·ΔT

[0059] where, c p is the specific heat capacity at constant pressure of the molten salt; ρ is the density of the molten salt, obtained by referring to the temperature-density relationship curve of the molten salt; q v is the volume flow rate of the molten salt, measured by a flow measurement device; ΔT is the temperature change of the molten salt.

[0060] In step S4, calculating the energy fluctuation coefficient specifically includes comprehensively considering the amplitude, rate, and duration of the change in the system energy power. The calculation formula is as follows:

[0061]

[0062] Among them, t is the current moment, and T is the set time window; P(i) represents the system energy power at moment i. is the average energy power within the time interval [t - T, t]. w1, w2, and w3 are weight coefficients, and w1 + w2 + w3 = 1, respectively reflecting the influence of the deviation between the current energy power and the average power, the change rate of the energy power, and the cumulative deviation of the energy power on the fluctuation coefficient; Δt is the time interval between adjacent measurement moments, and T is the duration length for calculating the cumulative deviation of the energy power, and T < t.

[0063] The step S5 energy fluctuation coefficient and valve collaborative control classification strategy includes setting a first threshold EFC1 and a second threshold EFC2, and setting the following classification according to the thresholds:

[0064] Slight fluctuation, that is, 0 < EFC(t) ≤ EFC1. At this time, the control system sends a fine-tuning instruction to the regulating valve according to the specific value of the energy fluctuation coefficient. If EFC(t) is close to the upper limit EFC1 of the slight fluctuation, the regulating valve will reduce the opening; if EFC(t) is close to the lower limit, the opening will be fine-tuned to maintain the flow stability, and the electric stop valve remains fully open.

[0065] Moderate fluctuation, that is, EFC1 < EFC(t) ≤ EFC2. At this time, the control system issues a larger adjustment instruction to the regulating valve according to the energy fluctuation coefficient and the fluctuation trend. If the system energy fluctuation shows an upward trend, the regulating valve quickly reduces the opening; if the fluctuation shows a downward trend and is close to the normal range, the regulating valve moderately increases the opening, and the electric stop valve remains fully open.

[0066] Severe fluctuation, that is, EFC(t) > EFC2. At this time, the control system immediately issues an instruction to close the electric stop valve, cut off the pipeline, prevent the flow of steam or molten salt, isolate the molten salt system from the high-pressure cylinder. At the same time, the regulating valve is closed to the minimum opening. After the system fault is eliminated and stabilized, according to the recovery situation of the energy fluctuation coefficient, first slowly open the regulating valve to make a tentative adjustment to the system. After the system is stable, further adjust the opening according to the energy fluctuation condition. If the energy fluctuation coefficient continues to be stable within the normal range, slowly open the electric stop valve to restore the normal operation of the system.

[0067] Step S6 Feedback and optimization, specifically after the valve action, the sensor continuously monitors the operating parameters of the system and feeds these data back to the control system in real time; the control system compares and analyzes the feedback data with the set standard parameters, re-evaluates the calculation parameters of the energy fluctuation coefficient, and adjusts the weight coefficients w1, w2, w3.

[0068] A safety control system for an extraction steam energy storage high-temperature molten salt energy storage system, which includes a data acquisition module, a data processing module, a central control module, and a feedback and optimization module. The data acquisition module collects data at key positions of the system through various sensors; the data processing module performs data preprocessing, energy power calculation, and energy fluctuation coefficient calculation; the central control module receives the results of the data processing module, compares the thresholds and controls the valves, and analyzes the feedback data, adjusts the calculation parameters and control strategies; the data analysis unit of the feedback and optimization module analyzes the feedback data, and the strategy adjustment unit assists the central control module to optimize the parameters and strategies.

[0069] Example 1: Taking a 600MW subcritical thermal power unit as an example, using ternary molten salt as the heat storage medium, heat is stored during the low load of the thermal power unit and released during the high load of the thermal power unit, and the load is deeply adjusted in cooperation with the thermal power unit. The main systems for heat storage and release are divided into a molten salt heat storage system, an extraction steam-heat storage system, a molten salt-steam generation SGS system, etc.

[0070] The heat storage process is as follows: When the unit needs to perform deep peak shaving, the extracted main steam is cooled by the molten salt heat exchanger in the molten salt heat storage system, and then part of the steam is mixed with the reheated steam section steam cooled by the molten salt heat exchanger and then returned to the reheated cold section steam system. The remaining steam is cooled to the subcooled water state by the steam heat exchanger and then returned to the power plant thermal system; the extracted reheated steam section steam is cooled by the molten salt heat exchanger and then is ejected to the reheated cold section steam by the main steam through the pressure matcher to ensure that the reheater does not exceed the temperature. The molten salt absorbs the heat released by the main steam and reheated steam from the low-temperature tank through the steam / molten salt heat exchanger and is stored in the high-temperature molten salt tank.

[0071] The heat release process is as follows: The feed water enters the molten salt-steam generation SGS system, passes through the preheater, evaporator and steam drum, is gradually evaporated by the molten salt heating, and then is continuously heated by the high-temperature molten salt in the superheater to reach the appropriate outlet temperature and return to the reheated cold section steam. The high-temperature molten salt returns to the low-temperature molten salt tank after releasing heat through the superheater-evaporator-preheater. The working principle is shown in Figure 2 .

[0072] See Figure 3 , the main steam introduction point of the heat storage system and the heat return point of the heat release system are both located at the exhaust pipe of the high-pressure cylinder. Currently, there are two isolation gate valves installed on this pipeline, and it takes 6 minutes for the valves to close fully. When an accident occurs in the molten salt system, the valves cannot be closed in time to isolate from the main engine, which poses a safety hazard.

[0073] Now, an electric stop valve and a regulating valve are added beside the two isolation gate valves on the connecting pipeline between the high-pressure cylinder exhaust pipe and the molten salt system, and these two valves are connected to the control system. The electric stop valve is mainly used to quickly cut off the flow of steam or molten salt in the pipeline in case of emergency, playing a key role in isolating the system; the regulating valve is used to precisely adjust the flow rate of steam or molten salt to meet the operating requirements of the system under different working conditions. Through the control system, these two valves can be remotely operated and automatically controlled, improving the system response speed and safety. Temperature sensors, pressure sensors, and flow sensors are used to monitor the system in real time. The temperature sensor is responsible for obtaining the temperature data of steam and molten salt in real time, because the temperature change directly reflects the energy change in the system. The pressure sensor measures the pressure in the system, and abnormal pressure may cause safety problems such as pipeline rupture. The flow sensor obtains the flow data of steam and molten salt. Calculate the energy power of steam and molten salt respectively. The system energy power P is the sum of the two, that is, P = P 蒸汽 +P 熔盐 , where the calculation formula for the energy power of steam is P 蒸汽 =h·q m , where h is the enthalpy, obtained from the steam thermodynamic property chart; q m is the density of steam. The calculation formula for the energy power of molten salt is P 熔盐 =c p ·ρ·q v ·ΔT, where c p is the specific heat capacity at constant pressure of molten salt; ρ is the density of molten salt, obtained from the temperature-density relationship curve of molten salt; q v is the volume flow rate of molten salt, measured by the flow measurement device; ΔT is the temperature change of molten salt.

[0074] The energy fluctuation coefficient comprehensively considers the amplitude, rate, and duration of the change in the system energy power. The calculation formula is:

[0075] where t is the current moment, T is the set time window; P(i) represents the system energy power at moment i; is the average energy power within the time interval [t - T, t], w1, w2, w3 are weight coefficients, and w1 + w2 + w3 = 1, respectively reflecting the influence of the deviation between the current energy power and the average power, the energy power change rate, and the energy power cumulative deviation on the fluctuation coefficient; Δt is the time interval between adjacent measurement moments, T is the duration length for calculating the energy power cumulative deviation, and T < t.

[0076] Set the first threshold EFC1 and the second threshold EFC2, and perform hierarchical control according to different ranges of the energy fluctuation coefficient: Slight fluctuation, that is, 0 < EFC(t) ≤ EFC1. At this time, the control system sends a fine-tuning command to the regulating valve according to the specific value of the energy fluctuation coefficient. If EFC(t) is close to the upper limit EFC1 of slight fluctuation, the regulating valve will reduce the opening; if EFC(t) is close to the lower limit, the opening will be fine-tuned to maintain the flow stability, and the motorized globe valve remains fully open.

[0077] Moderate fluctuation, that is, EFC1 < EFC(t) ≤ EFC2. At this time, the control system issues a larger adjustment command to the regulating valve according to the energy fluctuation coefficient and the fluctuation trend. If the system energy fluctuation shows an upward trend, the regulating valve quickly reduces the opening; if the fluctuation shows a downward trend and is close to the normal range, the regulating valve moderately increases the opening, and the motorized globe valve remains fully open.

[0078] Severe fluctuation, that is, EFC(t) > EFC2. At this time, the control system immediately issues a command to close the motorized globe valve, cut off the pipeline, prevent the flow of steam or molten salt, isolate the molten salt system from the high-pressure cylinder. At the same time, the regulating valve is closed to the minimum opening. After the system fault is eliminated and stabilized, according to the recovery of the energy fluctuation coefficient, first slowly open the regulating valve to perform a tentative adjustment on the system. After the system is stable, further adjust the opening according to the energy fluctuation condition. If the energy fluctuation coefficient continues to be stable within the normal range, slowly open the motorized globe valve to resume the normal operation of the system.

[0079] After the valve action, the sensor continuously monitors the operating parameters of the system and real-time feeds back this data to the control system. The control system compares and analyzes the feedback data with the set standard parameters, re-evaluates the calculation parameters of the energy fluctuation coefficient, and adjusts the weight coefficient to optimize the control strategy, so that the system can better adapt to different operating conditions.

Claims

1. A method for controlling the safety of high-temperature molten salt energy storage by extracting steam energy, characterized in that: It includes the following steps: S1: Add valves, including adding an electric globe valve, a regulating valve and a control system; S2: Data collection, real-time monitoring of the temperature and flow data of steam and molten salt, and measurement of the pressure inside the system; S3: Calculate the system energy power, including the calculation of the energy power of steam and the energy power of molten salt; S4: Calculate the energy fluctuation coefficient, comprehensively considering the amplitude, rate and duration of the change in the system energy power; S5: Hierarchical strategy for coordinated control of the energy fluctuation coefficient and the valves; S6: Feedback and optimization.

2. A steam extraction storage high temperature molten salt energy storage safety control method according to claim 1, characterized in that: In step S1, adding valves specifically includes adding an electric globe valve and a regulating valve on the connecting pipe between the exhaust pipe of the high-pressure cylinder and the molten salt system, and connecting the control system to the electric globe valve and the regulating valve.

3. A steam extraction storage high temperature molten salt energy storage safety control method according to claim 1, characterized in that: The data collection in step S2 includes using a temperature sensor to real-time monitor the temperature of steam and molten salt, a pressure sensor to measure the pressure inside the system, and a flow sensor to obtain the flow data of steam and molten salt.

4. A steam extraction storage high temperature molten salt energy storage safety control method according to claim 1, characterized in that: Calculating the system energy power in step S3 includes the calculation of the energy power of steam and the energy power of molten salt. The system energy power P is the sum of the energy power of steam and the energy power of molten salt, and its formula is: P=P 蒸汽 +P 熔盐 Among them, P 蒸汽 is the steam energy power, P 熔盐 is the molten salt energy power.

5. A steam extraction storage high temperature molten salt energy storage safety control method according to claim 4, characterized in that: The calculation formula for the energy power of the steam is: P 蒸汽 =h·q m Where h is the specific enthalpy of steam, which can be found from the thermodynamic properties diagram of steam; q m is the mass flow rate of steam, which is obtained by multiplying the previous volume flow rate by the steam density.

6. A steam extraction storage high temperature molten salt energy storage safety control method according to claim 4, characterized in that: The calculation formula for the energy power of the molten salt is P 熔盐 =c p ·ρ·q v ·ΔT Among them, c p is the constant pressure specific heat capacity of the molten salt; ρ is the density of the molten salt, which can be obtained from the temperature-density relationship curve of the molten salt; q v is the volume flow rate of molten salt, measured by the flow measurement device; ΔT is the temperature change of molten salt.

7. A steam extraction storage high temperature molten salt energy storage safety control method according to claim 1, characterized in that: The calculation of the energy fluctuation coefficient in step S4 specifically includes that the energy fluctuation coefficient comprehensively considers the amplitude, rate and duration of the change in the system energy power, and the calculation formula is as follows: Where t is the current time, T is the set time window; P(i) represents the system energy power at time i; is the average energy power in the time interval [tT, t], w1, w2, w3 are weight coefficients, and w1+w2+w3=1, which respectively reflect the influence of the current energy power deviation from the average power, the energy power change rate, and the energy power cumulative deviation on the fluctuation coefficient; Δt is the time interval between adjacent measurement moments, T is the duration of calculating the energy power cumulative deviation, and T <t。 8. The method for controlling the safety of high-temperature molten salt energy storage by extracting steam energy according to claim 1, characterized in that: The hierarchical strategy for coordinated control of the energy fluctuation coefficient and the valves in step S5 includes setting a first threshold EFC1 and a second threshold EFC2, and setting the following levels according to the thresholds: Slight fluctuation, that is, 0 < EFC(t) ≤ EFC1. At this time, the control system sends a fine-tuning instruction to the regulating valve according to the specific value of the energy fluctuation coefficient. If EFC(t) is close to the upper limit EFC1 of the slight fluctuation, the regulating valve will reduce the opening; if EFC(t) is close to the lower limit, the opening will be fine-tuned to maintain the flow stability, and the electric globe valve remains fully open; Moderate fluctuation, that is, EFC1 < EFC(t) ≤ EFC2. At this time, the control system issues a larger adjustment instruction to the regulating valve according to the energy fluctuation coefficient and the fluctuation trend. If the system energy fluctuation shows an upward trend, the regulating valve quickly reduces the opening; If the fluctuation shows a downward trend and is close to the normal range, the regulating valve moderately increases the opening, and the electric globe valve remains fully open; Severe fluctuation, that is, EFC(t) > EFC2. At this time, the control system immediately issues an instruction to close the electric globe valve, cut off the pipeline, prevent the flow of steam or molten salt, isolate the molten salt system from the high-pressure cylinder. At the same time, the regulating valve is closed to the minimum opening. After the system failure is eliminated and stabilized, according to the recovery of the energy fluctuation coefficient, first slowly open the regulating valve to make a tentative adjustment to the system. After the system is stable, further adjust the opening according to the energy fluctuation condition. If the energy fluctuation coefficient continues to be stable within the normal range, slowly open the electric globe valve to resume the normal operation of the system.

9. A steam extraction storage high temperature molten salt energy storage safety control method according to claim 1, characterized in that: Step S6 feedback and optimization, specifically, after the valve is actuated, the sensor continuously monitors the operating parameters of the system and feeds these data back to the control system in real time; the control system compares and analyzes the feedback data with the set standard parameters, re-evaluates the calculation parameters of the energy fluctuation coefficient, and adjusts the weight coefficients w1, w2, and w3.

10. A steam extraction energy storage high-temperature molten salt energy storage safety control system, comprising a data acquisition module, a data processing module, a central control module and a feedback and optimization module. The data acquisition module collects system key position data through various sensors; the data processing module performs data preprocessing, energy power calculation and energy fluctuation coefficient calculation; the central control module receives the results of the data processing module, compares the threshold and controls the valve, and analyzes the feedback data, adjusts the calculation parameters and control strategy; the data analysis unit of the feedback and optimization module analyzes the feedback data, and the strategy adjustment unit assists the central control module in optimizing parameters and strategies.

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