A molten salt and water cascade energy storage system and scheduling method

Abstract

The present invention provides a molten salt and water cascade energy storage system and a scheduling method, belonging to the technical field of heat exchange equipment, and specifically comprising: an air compressor unit, a heat storage and exchange system, a gas storage reservoir and a turbine, wherein the heat storage and exchange system comprises a low-temperature molten salt tank, a high-temperature molten salt tank, a low-temperature water tank, a high-temperature water tank, a molten salt heat exchanger and a water heat exchanger, and molten salt heat exchangers and water heat exchangers are correspondingly provided between the connection loops between the air compressor unit and the gas storage reservoir, and between the turbine and the gas storage reservoir, the low-temperature molten salt tank and the high-temperature molten salt tank are connected by means of the molten salt heat exchanger in the connection loops between the air compressor unit and the gas storage reservoir, and between the turbine and the gas storage reservoir, and the low-temperature water tank and the high-temperature water tank are connected by means of the water heat exchanger in the connection loops between the air compressor unit and the gas storage reservoir, and between the turbine and the gas storage reservoir, thereby improving the heat energy recovery rate.

Description

Technical Field

[0001] The present invention belongs to the technical field of heat exchange equipment, and in particular relates to a molten salt and water cascade energy storage system and a scheduling method. Background Art

[0002] For energy systems that include compressed air, turbines, and molten salt energy storage systems, existing molten salt energy storage systems have difficulty achieving low temperatures. Currently, existing products on the market can only be used up to 180°C, and the low-temperature portion can only be recovered through water. A similar technical solution is provided in invention patent application CN202510430176.9, "A Molten Salt Heat Storage System and Control Method Based on Electricity Price Regulation."

[0003] However, in the above technical solution, if only a molten salt and water cascade energy storage system is used, a large amount of heat energy will not be collected after the compressed air passes through the heat exchanger, resulting in energy waste; for water, if the operating temperature is too high, the cost of the storage system will increase and the water storage tank will be difficult to manufacture.

[0004] Therefore, in order to solve the above technical problems, the present application provides a molten salt and water cascade energy storage system and a scheduling method. Summary of the Invention

[0005] To achieve the purpose of the present invention, the present invention adopts the following technical solutions:

[0006] Specifically, the present application provides a molten salt and water cascade energy storage system, which has high energy utilization efficiency and flexible regulation.

[0007] To achieve the above-mentioned purpose of the invention, the present application provides a molten salt and water cascade energy storage system, comprising the following contents:

[0008] An air compressor unit, a heat storage and exchange system, a gas storage reservoir and a turbine, wherein the heat storage and exchange system includes a low-temperature molten salt tank, a high-temperature molten salt tank, a low-temperature water tank, a high-temperature water tank, a molten salt heat exchanger and a water heat exchanger. Molten salt heat exchangers and water heat exchangers are correspondingly provided between the connection loops between the air compressor unit and the gas storage reservoir, and between the turbine and the gas storage reservoir. The low-temperature molten salt tank and the high-temperature molten salt tank are connected using the molten salt heat exchanger in the connection loops between the air compressor unit and the gas storage reservoir, and between the turbine and the gas storage reservoir. The low-temperature water tank and the high-temperature water tank are connected using the water heat exchanger in the connection loops between the air compressor unit and the gas storage reservoir, and between the turbine and the gas storage reservoir.

[0009] A further technical solution is that when the low-temperature molten salt tank and the high-temperature molten salt tank are connected using the molten salt heat exchanger in the connecting loop between the air compressor unit and the gas storage reservoir and the turbine and the gas storage reservoir, valves are provided between the energy release loop and the energy storage loop of the low-temperature molten salt tank and the high-temperature molten salt tank and the molten salt heat exchanger.

[0010] A further technical solution is that when the low-temperature water tank and the high-temperature water tank are connected using the water heat exchanger in the connecting circuit between the air compressor unit and the gas storage reservoir, and the turbine and the gas storage reservoir, valves are provided between the energy release circuit and the energy storage circuit of the low-temperature water tank and the high-temperature water tank and the water heat exchanger.

[0011] A further technical solution is that the low-temperature molten salt tank and the high-temperature molten salt tank constitute a molten salt and water cascade energy storage system, and the low-temperature water tank and the high-temperature water tank constitute a water storage and heat exchange system.

[0012] A further technical solution is that when the cascade energy storage heating and power generation system is in the energy storage mode, it includes the following contents:

[0013] The molten salt and water cascade energy storage system and the water storage and heat exchange system start to operate. The low-temperature molten salt flows from the low-temperature molten salt tank through the molten salt heat exchanger and returns to the low-temperature molten salt tank. The low-temperature water flows from the low-temperature water tank through the water heat exchanger and returns to the low-temperature water tank. Then, when the target conditions are met, the air compressor unit starts to operate. Finally, the gas storage reservoir opens to store gas.

[0014] A further technical solution is that when the cascade energy storage heating and power generation system stops, the following steps are included:

[0015] The air compressor unit stops running, the molten salt and water cascade energy storage system and the water storage heat exchange system stop running, the molten salt heat exchanger and the water heat exchanger stop running, and the high-temperature molten salt tank and the high-temperature water tank enter the static stage.

[0016] It is understandable that when the cascade energy storage heating and power generation system is in the energy release mode, it includes the following:

[0017] High-temperature molten salt flows from the high-temperature molten salt tank through the molten salt heat exchanger and returns to the low-temperature molten salt tank, and high-temperature water flows from the high-temperature water tank through the water heat exchanger and returns to the low-temperature water tank; then, the gas storage begins to release gas; finally, the turbine starts to run.

[0018] Furthermore, when the cascade energy storage heating and power generation system is in the startup stage, the molten salt heat exchanger is used to heat the molten salt medium of the low-temperature molten salt tank, and the cold side molten salt outlet temperature of the molten salt heat exchanger is monitored in real time. When the outlet temperature reaches the design energy storage temperature of the high-temperature molten salt tank, the control system switches the flow pipeline of the molten salt, and the molten salt in the low-temperature molten salt tank flows into the high-temperature molten salt tank through the molten salt heat exchanger.

[0019] It is understandable that when the low-temperature molten salt tank of the cascade energy storage heating and power generation system, and the connecting pipes and valves of the low-temperature molten salt tank are frozen and blocked, the following are included:

[0020] The hot water storage and heat exchange system stops running immediately, the control system switches the compressed air circulation line, discharges the high-temperature compressed air into the atmosphere through the exhaust port, and shuts down the air compressor unit according to the preset descent rate.

[0021] Furthermore, when a failure occurs in the hot water storage and heat exchange system on the high temperature side of the cascade energy storage heating and power generation system, the following steps are included:

[0022] Start the standby high-pressure hot water tank to provide heat exchange medium to the water heat exchanger, and gradually adjust the gas storage discharge flow according to the preset discharge rate until the flow and temperature requirements of the compressed air in the air compressor unit are met. Then, shut down the turbine. Finally, the molten salt and water cascade energy storage system and the hot water storage and heat exchange system stop operating.

[0023] The high-temperature side hot water storage and heat exchange system includes a high-temperature water tank, connecting pipes of the high-temperature water tank, valves and a water heat exchanger.

[0024] In a second aspect, the present application provides a scheduling method for a molten salt and water cascade energy storage system, which is applied to the above-mentioned molten salt and water cascade energy storage system, specifically comprising:

[0025] S1 obtains energy storage regulation data of the molten salt and water cascade energy storage system, and determines the energy storage response deviation of the low-temperature molten salt system at different operating temperatures based on the energy storage regulation data. When the energy storage response deviation meets the requirements, proceed to the next step;

[0026] S2: determining a target energy storage adjustment period based on energy storage adjustment data on different dates, determining distribution data of the target energy storage adjustment period on different dates, and determining, based on the distribution data, when a distribution dispersion degree of the target energy storage adjustment period meets a requirement, determining an optimized period of a temperature control strategy within the target energy storage adjustment period based on the distribution data;

[0027] S3 determines the temperature treatment strategy of the low-temperature molten salt tank in different optimization periods based on the energy storage response deviation in different optimization periods and the time required for different operating temperatures to reach the target operating temperature that meets the energy storage regulation requirements of the high-temperature molten salt tank.

[0028] A further technical solution is that the energy storage regulation data includes the number of energy storage regulation times of the molten salt and water cascade energy storage system and the energy storage regulation amounts for different energy storage regulation times.

[0029] A further technical solution is that the energy storage response deviation at the operating temperature includes the energy storage regulation rate at different operating temperatures and the deviation between the energy storage regulation rate requirement and the energy storage regulation rate at different historical energy storage regulation times.

[0030] A further technical solution is that the method for determining the temperature treatment strategy of the low-temperature molten salt tank in the optimization period is:

[0031] Based on the energy storage response deviations in different optimization periods, determining the number of energy storage adjustments during which the energy storage regulation rate requirement in the optimization period cannot meet the requirements, and using this number as the regulation deviation number;

[0032] The time required to reach the target operating temperature required for energy storage regulation of the high-temperature molten salt tank at different operating temperatures is used to determine the regulation processing time at the available temperature.

[0033] The temperature treatment strategy of the low-temperature molten salt tank in the optimization period is determined according to the number of adjustment deviations and the adjustment treatment duration.

[0034] Specifically, the energy storage adjustment rate requirement cannot meet the required number of energy storage adjustments, which is the number of energy storage adjustments when the energy storage adjustment rate is less than the energy storage adjustment rate requirement during energy storage adjustment.

[0035] Compared with the prior art, the present invention has the following beneficial effects:

[0036] During energy storage, the high-temperature compressed air generated by the air compressor flows sequentially through a molten salt heat exchanger and a water heat exchanger. During energy release, the low-temperature compressed air within the gas storage reservoir flows sequentially through a water heat exchanger and a molten salt heat exchanger. The operating temperature range of the molten salt (wide-temperature molten salt) heat storage medium in the molten salt and water cascade energy storage system is 180°C to 600°C, while the operating temperature range of the water (pressurized water) heat storage medium in the hot water heat storage system is 40°C to 185°C. Combining the two enables cascaded heat storage and exchange, cooling the compressed air from, for example, 350°C to 40°C and collecting and storing (substantially) all of the released heat energy. This fully utilizes the respective characteristics of molten salt and water, maximizing the maximum energy storage capacity of the heat storage and exchange system, improving the system's energy storage and power generation efficiency, and reducing system costs. While achieving low-temperature molten salt is difficult, it can achieve both high-temperature power generation and cascaded energy utilization, while also reducing costs. The expansion process corresponds to this, and the heat storage medium water and the heat storage medium molten salt are heated in sequence from low to high temperature, thereby releasing (substantially) all the stored thermal energy.

[0037] The coupling degree between the molten salt and water cascade energy storage system and the hot water storage and heat exchange system within the "cascade heat storage" system is high, and their behaviors will be more closely related to each other. By designing a control system, it can monitor the inlet and outlet temperatures and flow rates of each pipeline in real time, judge the flow state of the medium in the pipe, and respond to abnormal temperature, abnormal flow and other problems in a timely manner. It can also control the electronic flow valve to realize flow regulation and flow line switching in a timely manner.

[0038] In order to prevent emergency situations that seriously endanger the safe operation of the system, such as power outages, molten salt pump failures, and hot water pump failures, the system can also be equipped with spare high-pressure hot water storage tanks and high-pressure compressed air storage tanks to serve as heat sources or power sources in emergency situations to shut down the system safely and orderly. The high-pressure hot water storage tanks and high-pressure compressed air storage tanks can further compress the medium in the high-temperature water tanks and high-temperature molten salt tanks for storage or collection of super-high-temperature compressed air. The pressure in the high-pressure hot water storage tanks and high-pressure compressed air storage tanks must be high enough, or the gravitational potential energy of the storage tank arrangement must be large enough to ensure that during the period of emergency shutdown of the turbine, heat supply can be completed or the molten salt can be pushed back to the storage tank without external force.

[0039] Based on the energy storage response deviation in different optimization periods and the time required for different operating temperatures to reach the target operating temperature that meets the energy storage regulation of the high-temperature molten salt tank, the temperature treatment strategy of the low-temperature molten salt tank in different optimization periods is determined, thereby achieving optimized adjustment of the temperature treatment strategy of the low-temperature molten salt tank in the optimization period with greater energy storage regulation demand and higher regulation rate demand, ensuring that the low-temperature molten salt tank can operate in a reasonable temperature range, thereby improving the efficiency of energy storage regulation processing.

[0040] Other features and advantages will be described in the following description. The objectives and other advantages of the present invention are realized and obtained by the structures particularly pointed out in the description and drawings.

[0041] In order to make the above-mentioned objects, features and advantages of the present invention more obvious and easy to understand, preferred embodiments are given below and described in detail with reference to the accompanying drawings. BRIEF DESCRIPTION OF THE DRAWINGS

[0042] The above and other features and advantages of the present invention will become more apparent by describing in detail example embodiments thereof with reference to the accompanying drawings;

[0043] Figure 1 It is a framework diagram of a molten salt and water cascade energy storage system;

[0044] Figure 2 It is a schematic diagram of the startup process in the molten salt and water cascade energy storage system;

[0045] Figure 3 It is a schematic diagram of temperature control during system operation;

[0046] Figure 4 This is a schematic diagram of the abnormal handling strategy when freezing and blocking occurs;

[0047] Figure 5 It is a schematic diagram of the abnormal handling strategy when a failure occurs in the hot water storage heat exchange system on the high temperature side;

[0048] Figure 6It is a flow chart of a scheduling method for a molten salt and water cascade energy storage system;

[0049] Figure 7 It is a flow chart for judging whether the energy storage response deviation meets the requirements;

[0050] Figure 8 The present invention is a flow chart of a method for determining a temperature treatment strategy of a low-temperature molten salt tank in an optimization period. DETAILED DESCRIPTION

[0051] To help those skilled in the art better understand the technical solutions in this specification, the following will provide a clear and complete description of the technical solutions in the embodiments of this specification, in conjunction with the accompanying drawings. Obviously, the described embodiments are only part of the embodiments of this specification, not all of them. All other embodiments obtained by those skilled in the art based on the embodiments of this specification without creative work should fall within the scope of protection of this specification.

[0052] Example 1

[0053] Specifically, such as Figure 1 As shown, a molten salt and water cascade energy storage system includes the following:

[0054] An air compressor unit, a heat storage and exchange system, a gas storage reservoir and a turbine, wherein the heat storage and exchange system includes a low-temperature molten salt tank, a high-temperature molten salt tank, a low-temperature water tank, a high-temperature water tank, a molten salt heat exchanger and a water heat exchanger. Molten salt heat exchangers and water heat exchangers are correspondingly provided between the connection loops between the air compressor unit and the gas storage reservoir, and between the turbine and the gas storage reservoir. The low-temperature molten salt tank and the high-temperature molten salt tank are connected using the molten salt heat exchanger in the connection loops between the air compressor unit and the gas storage reservoir, and between the turbine and the gas storage reservoir. The low-temperature water tank and the high-temperature water tank are connected using the water heat exchanger in the connection loops between the air compressor unit and the gas storage reservoir, and between the turbine and the gas storage reservoir.

[0055] Furthermore, when the low-temperature molten salt tank and the high-temperature molten salt tank are connected using the molten salt heat exchanger in the connecting loop between the air compressor unit and the gas storage reservoir, and the turbine and the gas storage reservoir, valves are provided between the energy release loop and the energy storage loop of the low-temperature molten salt tank and the high-temperature molten salt tank and the molten salt heat exchanger.

[0056] Specifically, when the low-temperature water tank and the high-temperature water tank are connected using the water heat exchanger in the connecting circuit between the air compressor unit and the gas storage reservoir, and the turbine and the gas storage reservoir, valves are provided between the energy release circuit and the energy storage circuit of the low-temperature water tank and the high-temperature water tank and the water heat exchanger.

[0057] It can be understood that the low-temperature molten salt tank and the high-temperature molten salt tank constitute a molten salt and water cascade energy storage system, and the low-temperature water tank and the high-temperature water tank constitute a water storage and heat exchange system.

[0058] Furthermore, when the cascade energy storage heating and power generation system is in the energy storage mode, the following contents are included:

[0059] The molten salt and water cascade energy storage system and the water storage and heat exchange system start to operate. The low-temperature molten salt flows from the low-temperature molten salt tank through the molten salt heat exchanger and returns to the low-temperature molten salt tank. The low-temperature water flows from the low-temperature water tank through the water heat exchanger and returns to the low-temperature water tank. Then, when the target conditions are met, the air compressor unit starts to operate. Finally, the gas storage reservoir opens to store gas.

[0060] Specifically, when the cascade energy storage heating and power generation system stops, the following steps are included:

[0061] The air compressor unit stops running, the molten salt and water cascade energy storage system and the water storage heat exchange system stop running, the molten salt heat exchanger and the water heat exchanger stop running, and the high-temperature molten salt tank and the high-temperature water tank enter the static stage.

[0062] It is understandable that when the cascade energy storage heating and power generation system is in the energy release mode, it includes the following:

[0063] High-temperature molten salt flows from the high-temperature molten salt tank through the molten salt heat exchanger and returns to the low-temperature molten salt tank, and high-temperature water flows from the high-temperature water tank through the water heat exchanger and returns to the low-temperature water tank; then, the gas storage begins to release gas; finally, the turbine starts to run.

[0064] Furthermore, when the cascade energy storage heating and power generation system is in the startup stage, the molten salt heat exchanger is used to heat the molten salt medium of the low-temperature molten salt tank, and the cold side molten salt outlet temperature of the molten salt heat exchanger is monitored in real time. When the outlet temperature reaches the design energy storage temperature of the high-temperature molten salt tank, the control system switches the flow pipeline of the molten salt, and the molten salt in the low-temperature molten salt tank flows into the high-temperature molten salt tank through the molten salt heat exchanger.

[0065] It is understandable that if Figure 2Figure 2 shows the startup process for a molten salt and water cascade energy storage system. The operating temperature range of the molten salt (wide-temperature lava) heat storage medium is 180°C to 600°C, while the operating temperature range of the water (pressurized water) heat storage medium in the hot water storage and heat exchange system is 40°C to 185°C. The temperature of the compressed air is 35-40°C. Since each system has a different optimal operating temperature range, temperature matching is crucial during system operation. During the initial operation of the energy storage process, the molten salt in the low-temperature molten salt tank is relatively low. After passing through the molten salt heat exchanger with high-temperature compressed air, its temperature may not reach the designed energy storage temperature of the high-temperature molten salt tank. Therefore, during the initial operation, the molten salt in the molten salt heat exchanger should be circulated back to the low-temperature molten salt tank. The control system monitors the molten salt outlet temperature on the cold side of the molten salt heat exchanger in real time. When the outlet temperature reaches the designed energy storage temperature of the high-temperature molten salt tank, the control system switches the molten salt flow channel, allowing the molten salt to flow into the high-temperature molten salt tank. (An "×" in the figure indicates device shutdown.)

[0066] During the energy storage process, at the initial stage of system operation, the water temperature in the low-temperature water tank is relatively low. After passing through the water heat exchanger with high-temperature compressed air, its temperature may not reach the designed energy storage temperature of the high-temperature water tank. Therefore, in the initial stage of operation, the water in the water heat exchanger should be circulated back to the low-temperature water tank. The control system monitors the outlet temperature of the cold side of the water heat exchanger in real time. When the outlet temperature reaches the designed energy storage temperature of the high-temperature water tank, the control system switches the water flow pipe, and the water flows into the high-temperature water tank. (The control strategy and water flow path are similar to those of the molten salt and water cascade energy storage system described above.)

[0067] When the system is running, Figure 3 Figure 2 shows a schematic diagram of temperature control during system operation. As mentioned above, the molten salt and water cascade energy storage system and the hot water storage and heat exchange system switch the heat exchange medium flow channels to achieve temperature matching. Therefore, fluctuations in the heat exchange medium's temperature may cause fluctuations in the compressed air temperature. The control system monitors the compressed air's temperature before it enters the storage system. If the compressed air temperature exceeds the storage system's designed storage temperature, the control system switches the compressed air flow channel, storing the abnormally high compressed air in a backup compressed air tank or discharging it into the atmosphere through an exhaust port. This prevents the introduction of high-temperature compressed air into the storage system, which could affect its safe operation and storage capacity. (An "×" in the figure indicates a device is off.)

[0068] It is understandable that when the low-temperature molten salt tank of the cascade energy storage heating and power generation system, and the connecting pipes and valves of the low-temperature molten salt tank are frozen and blocked, the following are included:

[0069] The hot water storage and heat exchange system stops running immediately, the control system switches the compressed air circulation line, discharges the high-temperature compressed air into the atmosphere through the exhaust port, and shuts down the air compressor unit according to the preset descent rate.

[0070] It's important to note that molten salt is an excellent energy storage medium, but its freezing point is much higher than the ambient temperature. Low-temperature molten salt faces varying degrees of risk of freezing and blockage when passing through equipment, pipelines, and valves. Therefore, molten salt energy storage system pipelines require appropriate anti-freeze design measures, such as adjusting pipeline slopes, optimizing pipeline structures, and adding compressed air. Steam or electric heating technologies are also used to keep the molten salt molten, and to insulate the pipelines and equipment to minimize heat loss. Furthermore, if a freeze blockage occurs, the control system can quickly determine the blockage's location by monitoring the temperature and flow of the heat exchange medium.

[0071] like Figure 4 The figure below is a schematic diagram of the abnormal handling strategy for freezing blockage. During the energy storage process, if the low-temperature side equipment, pipelines, and valves freeze, most of the compressed air's heat cannot be stored in the molten salt and water cascade energy storage system, compromising the safe operation of both the hot water heat exchange system and the gas storage reservoir. When the control system detects freezing blockage of the low-temperature side molten salt by monitoring the temperature and flow of the heat exchange medium, it immediately shuts down the hot water heat exchange system to prevent the high-temperature compressed gas from abnormally heating the water and causing vaporization, which could threaten the safety of the hot water heat exchange system. The control system then switches the compressed air flow path, discharging the high-temperature compressed air into the atmosphere through the exhaust port. This prevents the high-temperature compressed air from entering the gas storage reservoir, which could affect its safe operation and storage capacity. Finally, the compressed air units are shut down in an orderly and slow manner. (In the figure, ! indicates a fault, numbers indicate the control sequence, and × indicates equipment shutdown).

[0072] The low-temperature side hot water storage and heat exchange system fault handling strategy involves the following: During energy storage, if a fault occurs on the low-temperature side of the hot water storage and heat exchange system, some of the compressed air's heat cannot be stored by the hot water storage and heat exchange system, preventing the compressed air temperature from being lowered to the gas storage's designed storage temperature. This compromises the safe operation of the gas storage. When the control system detects a fault on the low-temperature side of the hot water storage and heat exchange system by monitoring the temperature and flow of the heat exchange medium, it first switches the compressed air flow path, discharging the high-temperature compressed air into the atmosphere through the exhaust port. This prevents the high-temperature compressed air from entering the gas storage, which could affect its safe operation and storage capacity. Subsequently, the compressed air unit is shut down in an orderly and slow manner. Finally, the molten salt and water cascade energy storage system ceases operation. (The control strategy is similar to the low-temperature side molten salt freeze blockage treatment described above.)

[0073] Furthermore, when a failure occurs in the hot water storage and heat exchange system on the high temperature side of the cascade energy storage heating and power generation system, the following steps are included:

[0074] Start the standby high-pressure hot water tank to provide heat exchange medium to the water heat exchanger, and gradually adjust the gas storage discharge flow according to the preset discharge rate until the flow and temperature requirements of the compressed air in the air compressor unit are met. Then, shut down the turbine. Finally, the molten salt and water cascade energy storage system and the hot water storage and heat exchange system stop operating.

[0075] The high-temperature side hot water storage and heat exchange system includes a high-temperature water tank, connecting pipes of the high-temperature water tank, valves and a water heat exchanger.

[0076] like Figure 5 The figure below illustrates the abnormal handling strategy for a failure in the hot water storage and heat exchange system on the high-temperature side. During the energy release process, if the hot water storage and heat exchange system fails and the water heat exchanger fails to operate properly, the initial heating of the low-temperature compressed air cannot be achieved. This will cause the subsequent heat exchange conditions of the molten salt heat exchanger to deviate from the designed operating conditions, resulting in a decrease in the system's power generation efficiency and, in severe cases, jeopardizing the safe operation of the molten salt and water cascade energy storage system. The control system detects a failure on the high-temperature side of the hot water storage and heat exchange system by monitoring the temperature and flow of the heat exchange medium. First, the backup high-pressure hot water tank is activated to supply heat exchange medium to the water heat exchanger. Subsequently, the gas storage bleed flow rate is gradually adjusted to minimize energy loss. Subsequently, the turbine expander is gradually and orderly shut down to meet the compressed air flow and temperature requirements within the expander, ensuring a safe and orderly shutdown of the expander unit. Finally, the molten salt and water cascade energy storage system and the hot water storage and heat exchange system are shut down. (In the figure, ! indicates a failure, numbers indicate the control sequence, and × indicates device shutdown).

[0077] Fault handling strategy for the high-temperature side molten salt and water cascade energy storage system. During the energy release process, if the high-temperature side molten salt and water cascade energy storage system fails and the molten salt pump fails to operate properly, the molten salt heat exchanger will also fail to operate properly, preventing secondary heating of the low-temperature compressed air and reducing power generation efficiency. Furthermore, the turbine expander will experience a significant temperature drop. If the initial compressed air temperature is not high enough, moisture will condense within the compressed air, threatening the safe operation of the expander. When the control system detects a fault on the low-temperature side of the molten salt and water cascade energy storage system by monitoring the temperature and flow of the heat exchange medium, it first activates the high-pressure compressed air storage tank as a power source to propel the high-temperature molten salt to complete the heat exchange and activates the electric heater to ensure that the compressed air temperature meets the safe operation requirements of the turbine expander. Subsequently, the air discharge flow from the gas storage reservoir is gradually adjusted. The turbine expander is then shut down in a gradual and orderly manner to meet the compressed air flow and temperature requirements within the expander, ensuring a safe and orderly shutdown of the expander. Finally, the hot water storage heat exchange system is shut down. (The control strategy is similar to the fault handling strategy for the high-temperature side hot water storage heat exchange system described above.)

[0078] Example 2

[0079] Based on the deviation between the energy storage regulation rate and the energy storage regulation rate requirements for different historical energy storage regulation times, the regulation rate deviation at different operating temperatures is determined. Based on the regulation rate deviation, the regulation rate deviation times at different operating temperatures are determined. When there is no operating temperature at which the regulation rate deviation times meet the requirements, it is determined that the energy storage response deviation does not meet the requirements.

[0080] When the proportion of the number of dates in different energy storage regulation target periods is less than the preset proportion threshold, it means that the distribution dispersion of the energy storage regulation target period is relatively high, and it can be directly determined that the distribution dispersion of the energy storage regulation target period does not meet the requirements.

[0081] The optimized period of the temperature control strategy in the energy storage adjustment target period is the energy storage adjustment target period in which the number of dates accounts for more than the second number proportion threshold. In a possible embodiment, the energy storage adjustment target period in which the number of dates accounts for more than 0.5 is used as the optimized period.

[0082] Based on the energy storage response deviation in different optimization periods, the number of energy storage adjustments during which the energy storage regulation rate demand in the optimization period cannot meet the requirement is determined, and the number is used as the regulation deviation number. When the regulation deviation number does not meet the requirement, that is, when it is greater than a threshold, in order to ensure the regulation reliability of the optimization period, the operating temperature of the low-temperature molten salt tank is directly stabilized at an operating temperature that can meet the energy storage demand of the high-temperature molten salt tank. That is, at the operating temperature, there is no need to first heat the molten salt medium of the low-temperature molten salt tank, and the high-temperature molten salt tank can be directly used for energy storage regulation, that is, the molten salt medium of the low-temperature molten salt tank directly enters the high-temperature molten salt tank;

[0083] In addition, if the number of adjustment deviations meets the requirements, the number of adjustment deviations at this time is small. Therefore, the adaptation values ​​of different adjustment time available temperatures can be determined based on the adjustment processing time at the adjustment time available temperature, based on the number of adjustment deviations and the ratio of the number of adjustment deviations to the adjustment processing time, and the adjustment time available temperature with the adaptation value greater than the maximum adjustment processing time in the preset adaptation threshold is used as the temperature processing target of the low-temperature molten salt tank in the optimization period, wherein the preset adaptation threshold is determined according to the number of adjustment deviations, and the larger the number of adjustment deviations, the larger the preset adaptation threshold.

[0084] Second, as Figure 6 As shown, the present application provides a scheduling method for a molten salt and water cascade energy storage system, which is applied to the above-mentioned molten salt and water cascade energy storage system, specifically including:

[0085] S1 obtains energy storage regulation data of the molten salt and water cascade energy storage system, and determines the energy storage response deviation of the low-temperature molten salt system at different operating temperatures based on the energy storage regulation data. When the energy storage response deviation meets the requirements, proceed to the next step;

[0086] Furthermore, the energy storage regulation data includes the number of energy storage regulation times of the molten salt and water cascade energy storage system and the energy storage regulation amounts for different energy storage regulation times.

[0087] Specifically, the energy storage response deviation at the operating temperature includes the energy storage regulation rate at different operating temperatures and the deviation between the energy storage regulation rate requirement and the energy storage regulation rate at different historical energy storage regulation times.

[0088] It is understandable that when the operating temperature is low, during the startup of the molten salt and water cascade energy storage system, in order to avoid the temperature of the molten salt medium flowing into the low-temperature molten salt tank being too high, a lower heating temperature needs to be used, thereby making the energy storage regulation rate lower.

[0089] It should also be noted that during the startup process, when the molten salt heat exchanger is used to heat the low-temperature molten salt device, as the operating temperature increases, the flow rate of the molten salt medium gradually increases, which makes the heating rate of the molten salt medium gradually increase. Therefore, the difference in operating temperature will cause the energy storage regulation rate to change.

[0090] It should be noted that the operating temperature is the operating temperature of the low-temperature molten salt tank of the molten salt and water cascade energy storage system when it is not heated, that is, the operating temperature during normal operation when it is not in the energy storage regulation process.

[0091] Specifically, such as Figure 7 As shown, judging that the energy storage response deviation meets the requirements specifically includes:

[0092] Determine the energy storage regulation rate of the low-temperature molten salt system at different operating temperatures based on the energy storage response deviation of the low-temperature molten salt system, and determine the regulation rate deviation at different operating temperatures based on the deviation between the energy storage regulation rate and the energy storage regulation rate requirements for different historical energy storage regulation times;

[0093] determining the number of regulation rate deviations at different operating temperatures based on the regulation rate deviation;

[0094] Determine whether the energy storage regulation deviation meets the requirements according to the number of regulation rate deviations.

[0095] It can be understood that when there is no operating temperature at which the number of adjustment rate deviations meets the requirement, it is determined that the energy storage response deviation does not meet the requirement.

[0096] The specific number of regulation rate deviations is the number of historical energy storage adjustments in which the regulation rate deviation is greater than a preset deviation threshold.

[0097] It should be noted that when there is no operating temperature at which the number of adjustment rate deviations meets the requirements, that is, when the number of adjustment rate deviations is less than the preset adjustment number threshold, the operating temperature of the low-temperature molten salt tank is stabilized at an operating temperature that can meet the energy storage requirements of the high-temperature molten salt tank, that is, at the operating temperature, there is no need to first heat the molten salt medium of the low-temperature molten salt tank, and the high-temperature molten salt tank can be directly used for energy storage adjustment, that is, the molten salt medium of the low-temperature molten salt tank directly enters the high-temperature molten salt tank.

[0098] Optionally, determining whether the energy storage response deviation meets the requirements specifically includes:

[0099] S11 determines an energy storage regulation rate of the low-temperature molten salt system at different operating temperatures based on an energy storage response deviation of the low-temperature molten salt system, determines a regulation rate deviation at different operating temperatures based on a deviation between the energy storage regulation rate and energy storage regulation rate requirements for different historical energy storage regulation times, and determines the number of regulation rate deviations at different operating temperatures based on the regulation rate deviation;

[0100] It can be understood that in the above steps, if there is no operating temperature at which the number of adjustment rate deviations meets the requirements, that is, when the number of adjustment rate deviations is less than the operating temperature at the preset adjustment number threshold, the operating temperature of the low-temperature molten salt tank is stabilized at an operating temperature that can meet the energy storage requirements of the high-temperature molten salt tank, that is, at the operating temperature, there is no need to first perform a heating treatment on the molten salt medium of the low-temperature molten salt tank, and the high-temperature molten salt tank can be directly used for energy storage adjustment, that is, the molten salt medium of the low-temperature molten salt tank directly enters the high-temperature molten salt tank;

[0101] It should also be noted that even if there is an operating temperature at which the number of adjustment rate deviations meets the requirements, if at different operating temperatures, the number of adjustment rate deviations in which the adjustment rate deviation amount is not within the preset deviation amount range does not meet the requirements, that is, the number of adjustment rate deviations with larger adjustment rate deviation amounts is greater than the preset number threshold, then it is necessary to stabilize the operating temperature of the low-temperature molten salt tank at an operating temperature that can meet the energy storage requirements of the high-temperature molten salt tank, that is, at the operating temperature, there is no need to first heat the molten salt medium of the low-temperature molten salt tank, and the high-temperature molten salt tank can be directly used for energy storage regulation, that is, the molten salt medium of the low-temperature molten salt tank directly enters the high-temperature molten salt tank;

[0102] If the number of adjustment rate deviations where the adjustment rate deviation is not within the preset deviation range meets the requirements and the number of adjustment rate deviations meets the required operating temperature, it will be used as the available operating temperature and proceed to the next step for further judgment.

[0103] S12 determines the adjustment processing time of different operating temperatures based on the fastest time required for different operating temperatures to reach the target operating temperature that satisfies the high-temperature molten salt tank for energy storage adjustment;

[0104] It should be noted that, in the above steps, if the adjustment processing time at different available operating temperatures is greater than the preset adjustment time threshold, it means that the adjustment time at different available operating temperatures is too long. Therefore, in order to meet the energy storage adjustment demand, it is necessary to stabilize the operating temperature of the low-temperature molten salt tank at an operating temperature that can meet the energy storage demand of the high-temperature molten salt tank, that is, at the operating temperature, there is no need to first perform a heating treatment on the molten salt medium of the low-temperature molten salt tank, and the high-temperature molten salt tank can be directly used for energy storage adjustment, that is, the molten salt medium of the low-temperature molten salt tank directly enters the high-temperature molten salt tank;

[0105] When there is an operating temperature whose adjustment processing time is not greater than the preset adjustment time threshold, it is used as the adjustment time available temperature and the process proceeds to the next step.

[0106] S13 determines whether the energy storage regulation deviation meets the requirements according to the number of regulation rate deviations and regulation processing time at different operating temperatures.

[0107] In a possible embodiment, the preset time thresholds at different available adjustment time temperatures are determined based on the number of adjustment rate deviations at different available adjustment time temperatures. When there is no available adjustment time temperature at which the adjustment processing time is less than the preset time threshold, it is determined that the energy storage adjustment deviation does not meet the requirements.

[0108] It should also be noted that there is a preset corresponding relationship between the preset time threshold and the number of adjustment rate deviations, wherein the greater the number of adjustment rate deviations, the greater the preset time threshold.

[0109] S2: determining a target energy storage adjustment period based on energy storage adjustment data on different dates, determining distribution data of the target energy storage adjustment period on different dates, and determining, based on the distribution data, when a distribution dispersion degree of the target energy storage adjustment period meets a requirement, determining an optimized period of a temperature control strategy within the target energy storage adjustment period based on the distribution data;

[0110] Furthermore, the target energy storage adjustment period is a period in which the total number of historical energy storage adjustments in the period on different dates is greater than a preset energy storage adjustment number threshold.

[0111] Specifically, determining whether the distribution discreteness of the target energy storage regulation period meets the requirements specifically includes:

[0112] Using the distribution data of energy storage regulation target periods on different dates, determine the proportion of dates in different energy storage regulation target periods;

[0113] According to the proportion of the number of dates in different energy storage regulation target periods, it is determined whether the distribution dispersion degree of the energy storage regulation target period meets the requirements.

[0114] Specifically, when the proportion of the number of dates in different energy storage regulation target periods is less than the preset proportion threshold, it means that the distribution dispersion of the energy storage regulation target period is relatively high. Therefore, on this basis, it can be directly determined that the distribution dispersion of the energy storage regulation target period does not meet the requirements.

[0115] It should be noted that when the distribution discreteness of the energy storage adjustment target period does not meet the requirements, the operating temperature of the low-temperature molten salt tank will be stabilized at the operating temperature where the adjustment rate deviation number is less than the preset adjustment number threshold in different time periods, and the operating temperature with the shortest adjustment processing time will be adjusted.

[0116] Furthermore, the optimized period of the temperature control strategy in the energy storage adjustment target period is the energy storage adjustment target period in which the number of dates accounts for more than the second number proportion threshold. In a possible embodiment, the energy storage adjustment target period in which the number of dates accounts for more than 0.5 is used as the optimized period.

[0117] S3 determines the temperature treatment strategy of the low-temperature molten salt tank in different optimization periods based on the energy storage response deviation in different optimization periods and the time required for different operating temperatures to reach the target operating temperature that meets the energy storage regulation requirements of the high-temperature molten salt tank.

[0118] Specifically, such as Figure 8 As shown, the method for determining the temperature treatment strategy of the low-temperature molten salt tank in the optimization period is:

[0119] Based on the energy storage response deviations in different optimization periods, determining the number of energy storage adjustments during which the energy storage regulation rate requirement in the optimization period cannot meet the requirements, and using this number as the regulation deviation number;

[0120] The time required to reach the target operating temperature required for energy storage regulation of the high-temperature molten salt tank at different operating temperatures is used to determine the regulation processing time at the available temperature.

[0121] The temperature treatment strategy of the low-temperature molten salt tank in the optimization period is determined according to the number of adjustment deviations and the adjustment treatment duration.

[0122] Specifically, the energy storage adjustment rate requirement cannot meet the required number of energy storage adjustments, which is the number of energy storage adjustments when the energy storage adjustment rate is less than the energy storage adjustment rate requirement during energy storage adjustment.

[0123] It can be understood that when the number of adjustment deviations does not meet the requirements, that is, it is greater than the threshold, in order to ensure the adjustment reliability of the optimization period, the operating temperature of the low-temperature molten salt tank is directly stabilized at an operating temperature that can meet the energy storage requirements of the high-temperature molten salt tank. That is, at the operating temperature, there is no need to first heat the molten salt medium of the low-temperature molten salt tank, and the high-temperature molten salt tank can be directly used for energy storage adjustment, that is, the molten salt medium of the low-temperature molten salt tank directly enters the high-temperature molten salt tank.

[0124] In addition, if the number of adjustment deviations meets the requirements, the number of adjustment deviations at this time is small. Therefore, the adaptation values ​​of different adjustment time available temperatures can be determined based on the adjustment processing time at the adjustment time available temperature, based on the number of adjustment deviations and the ratio of the number of adjustment deviations to the adjustment processing time, and the adjustment time available temperature with the adaptation value greater than the maximum adjustment processing time in the preset adaptation threshold is used as the temperature processing target of the low-temperature molten salt tank in the optimization period, wherein the preset adaptation threshold is determined according to the number of adjustment deviations, and the larger the number of adjustment deviations, the larger the preset adaptation threshold.

[0125] In another embodiment, the method for determining the temperature treatment strategy of the low-temperature molten salt tank in the optimization period is:

[0126] S41 determines the number of energy storage adjustments during the optimization period during which the energy storage regulation rate demand cannot meet the requirements based on the energy storage response deviation in different optimization periods, and uses this number as the number of regulation deviations. The time required to reach the target operating temperature for energy storage regulation of the high-temperature molten salt tank at different operating temperatures is used to determine the regulation processing time at the available temperature.

[0127] It should be noted that when the number of adjustment deviations does not meet the requirements, that is, when it is greater than the threshold, in order to ensure the adjustment reliability of the optimization period, the operating temperature of the low-temperature molten salt tank is directly stabilized at an operating temperature that can meet the energy storage requirements of the high-temperature molten salt tank. That is, it is necessary to stabilize the operating temperature of the low-temperature molten salt tank at an operating temperature that can meet the energy storage requirements of the high-temperature molten salt tank. At the operating temperature, there is no need to first heat the molten salt medium of the low-temperature molten salt tank, and the high-temperature molten salt tank can be directly used for energy storage adjustment, that is, the molten salt medium of the low-temperature molten salt tank directly enters the high-temperature molten salt tank.

[0128] In addition, if the number of adjustment deviations meets the requirements, the number of adjustment deviations at this time is small. Therefore, the adaptation values ​​of different adjustment time available temperatures can be determined based on the adjustment processing time at the adjustment time available temperature, based on the adjustment deviation number, and based on the ratio of the adjustment deviation number to the adjustment processing time. When there is no adjustment time available temperature with an adaptation value greater than the preset adaptation threshold, it means that the operating temperature of the low-temperature molten salt tank needs to be stabilized at an operating temperature that can meet the energy storage requirements of the high-temperature molten salt tank. At the operating temperature, there is no need to first heat the molten salt medium of the low-temperature molten salt tank, and the high-temperature molten salt tank can be directly used for energy storage adjustment, that is, the molten salt medium of the low-temperature molten salt tank directly enters the high-temperature molten salt tank.

[0129] If there is an available temperature for adjustment time with an adaptation value greater than the preset adaptation threshold, the available temperature for adjustment time with an adaptation value greater than the preset adaptation threshold is used as the available control target and the process proceeds to the next step.

[0130] S42 determines, based on energy storage adjustment rate requirements in different adjustment deviation times and energy storage adjustment rates at different adjustment duration available temperatures, an adaptation deviation number in the adjustment deviation times when using the adjustment duration available temperature;

[0131] It can be understood that the number of adaptation deviations is the number of energy storage deviations in which the energy storage adjustment rate of the available temperature during the adjustment time is less than the energy storage adjustment rate requirement by an amount greater than a preset rate threshold.

[0132] In addition, it should be further explained that if there is an available control target whose number of adaptation deviations meets the requirements, that is, if there is an available control target whose number of adaptation deviations is less than the threshold, then the available control target with the smallest number of adaptation deviations is directly used as the temperature processing target of the low-temperature molten salt tank in the optimization period.

[0133] It should also be noted that if there is no available control target whose number of adaptation deviations meets the requirements, and the number of adaptation deviations under different available control targets is greater than the preset adaptation deviation number threshold, then the adjustment rates of different available control targets cannot meet the requirements. Therefore, on this basis, it is necessary to stabilize the operating temperature of the low-temperature molten salt tank at an operating temperature that can meet the energy storage requirements of the high-temperature molten salt tank. At the operating temperature, there is no need to first heat the molten salt medium of the low-temperature molten salt tank, and the high-temperature molten salt tank can be directly used for energy storage adjustment, that is, the molten salt medium of the low-temperature molten salt tank directly enters the high-temperature molten salt tank. When there is an available adjustment target whose number of adaptation deviations is not greater than the preset adaptation deviation number threshold, it is used as a screening adjustment target and directly proceeds to the next step.

[0134] S43 determines a temperature processing strategy for the low-temperature molten salt tank in the optimization period according to the number of adjustment deviations, the adjustment processing time at different available temperatures for different adjustment time periods, and the number of adaptation deviations.

[0135] In a possible embodiment, the adjustment power adaptation value is determined by the ratio of the number of adaptation deviations to the number of adjustment deviations, and the comprehensive adaptation value is determined according to the sum of the adjustment power adaptation value and the adaptation value. The screening adjustment target with the largest comprehensive adaptation value is used as the temperature processing target of the low-temperature molten salt tank in the optimization period.

[0136] In another embodiment, the adjustment power adaptation value is determined by the ratio of the adaptation deviation number to the adjustment deviation number, and the screening adjustment target with the largest product of the adjustment power adaptation value and the adaptation value is used as the temperature processing target of the low-temperature molten salt tank in the optimization period.

[0137] The various embodiments in this specification are described in a progressive manner. Similar portions between the various embodiments can be referenced to each other, and each embodiment focuses on the differences from the other embodiments. In particular, the device, apparatus, and non-volatile computer storage medium embodiments are generally similar to the method embodiments, so their descriptions are relatively simplified. For relevant details, refer to the descriptions of the method embodiments.

[0138] The foregoing description of this specification describes specific embodiments. Other embodiments are within the scope of the appended claims. In some cases, the actions or steps recited in the claims can be performed in an order different from that described in the embodiments and still achieve the desired results. Furthermore, the processes depicted in the accompanying drawings do not necessarily require the specific order shown or the sequential order to achieve the desired results. In certain embodiments, multitasking and parallel processing are also possible or may be advantageous.

[0139] The foregoing description is merely one or more embodiments of this specification and is not intended to limit this specification. It will be apparent to those skilled in the art that various modifications and variations may be made to one or more embodiments of this specification. Any modifications, equivalent substitutions, or improvements made within the spirit and principles of one or more embodiments of this specification are intended to be within the scope of the claims of this specification.

Claims

1. A scheduling method for a molten salt and water cascade energy storage system, characterized in that: Includes the following: An air compressor unit, a heat storage and exchange system, a gas storage reservoir, and a turbine, wherein the heat storage and exchange system includes a low-temperature molten salt tank, a high-temperature molten salt tank, a low-temperature water tank, a high-temperature water tank, a molten salt heat exchanger, and a water heat exchanger; molten salt heat exchangers and water heat exchangers are correspondingly provided between the connection loops between the air compressor unit and the gas storage reservoir, and between the turbine and the gas storage reservoir; the low-temperature molten salt tank and the high-temperature molten salt tank are connected using the molten salt heat exchanger in the connection loops between the air compressor unit and the gas storage reservoir, and between the turbine and the gas storage reservoir; and the low-temperature water tank and the high-temperature water tank are connected using the water heat exchanger in the connection loops between the air compressor unit and the gas storage reservoir, and between the turbine and the gas storage reservoir; Obtaining energy storage regulation data of the molten salt and water cascade energy storage system, and determining the energy storage response deviation of the low-temperature molten salt system at different operating temperatures based on the energy storage regulation data, and proceeding to the next step when the energy storage response deviation meets the requirements; Determining a target energy storage adjustment period based on energy storage adjustment data on different dates, determining distribution data of the target energy storage adjustment period on different dates, and determining, based on the distribution data, when a distribution dispersion degree of the target energy storage adjustment period meets a requirement, determining an optimized period of a temperature control strategy within the target energy storage adjustment period based on the distribution data; Based on the energy storage response deviation in different optimization periods and the time required for different operating temperatures to reach the target operating temperature that satisfies the high-temperature molten salt tank for energy storage regulation, the temperature treatment strategy for the low-temperature molten salt tank in different optimization periods is determined; The method for determining the temperature treatment strategy of the low-temperature molten salt tank in the optimization period is: Based on the energy storage response deviations in different optimization periods, determining the number of energy storage adjustments during which the energy storage regulation rate requirement in the optimization period cannot meet the requirements, and using this number as the regulation deviation number; The time required to reach the target operating temperature required for energy storage regulation of the high-temperature molten salt tank at different operating temperatures is used to determine the regulation processing time at the available temperature. The temperature treatment strategy of the low-temperature molten salt tank in the optimization period is determined according to the number of adjustment deviations and the adjustment treatment duration.

2. The scheduling method of a molten salt and water cascade energy storage system according to claim 1, characterized in that: When the low-temperature molten salt tank and the high-temperature molten salt tank are connected using the molten salt heat exchanger in the connection loop between the air compressor unit and the gas storage reservoir and the turbine and the gas storage reservoir, valves are provided between the energy release loop and the energy storage loop of the low-temperature molten salt tank and the high-temperature molten salt tank and the molten salt heat exchanger.

3. The scheduling method of a molten salt and water cascade energy storage system according to claim 1, characterized in that: When the low-temperature water tank and the high-temperature water tank are connected using the water heat exchanger in the connecting circuit between the air compressor unit and the gas storage reservoir, and the turbine and the gas storage reservoir, valves are provided between the energy release circuit and the energy storage circuit of the low-temperature water tank and the high-temperature water tank and the water heat exchanger.

4. The scheduling method of a molten salt and water cascade energy storage system according to claim 1, characterized in that: When the cascade energy storage heating system is in energy storage mode, it includes the following: The molten salt and water cascade energy storage system and the water storage and heat exchange system start to operate. The low-temperature molten salt flows from the low-temperature molten salt tank through the molten salt heat exchanger and returns to the low-temperature molten salt tank. The low-temperature water flows from the low-temperature water tank through the water heat exchanger and returns to the low-temperature water tank. Then, when the target conditions are met, the air compressor unit starts to operate. Finally, the gas storage reservoir opens to store gas.

5. The scheduling method of a molten salt and water cascade energy storage system according to claim 1, characterized in that: When the cascade energy storage heating system is in the energy release mode, it includes the following: The high-temperature molten salt flows from the high-temperature molten salt tank through the molten salt heat exchanger and returns to the low-temperature molten salt tank, and the high-temperature water flows from the high-temperature water tank through the water heat exchanger and returns to the low-temperature water tank; Then the gas reservoir begins to drain; finally, the turbine starts running.

6. The scheduling method of a molten salt and water cascade energy storage system according to claim 1, characterized in that: When the cascade energy storage heating system is in the startup stage, the molten salt medium of the low-temperature molten salt tank is heated by the molten salt heat exchanger, and the molten salt outlet temperature on the cold side of the molten salt heat exchanger is monitored in real time. When the outlet temperature reaches the designed energy storage temperature of the high-temperature molten salt tank, the control system switches the flow pipeline of the molten salt, and the molten salt in the low-temperature molten salt tank flows into the high-temperature molten salt tank through the molten salt heat exchanger.

7. The scheduling method of a molten salt and water cascade energy storage system according to claim 1, characterized in that: When the low-temperature molten salt tank of the cascade energy storage heating system, and the connecting pipes and valves of the low-temperature molten salt tank are frozen and blocked, the following are included: The hot water storage and heat exchange system stops running immediately, the control system switches the compressed air circulation line, discharges the high-temperature compressed air into the atmosphere through the exhaust port, and shuts down the air compressor unit according to the preset descent rate.

8. The scheduling method for a molten salt and water cascade energy storage system according to claim 1, characterized in that: When a failure occurs in the hot water storage and heat exchange system on the high temperature side of the cascade energy storage heating system, the following procedures are included: Start the standby high-pressure hot water tank to provide heat exchange medium to the water heat exchanger, and gradually adjust the gas storage discharge flow according to the preset discharge rate until the flow and temperature requirements of the compressed air in the air compressor unit are met. Then, shut down the turbine. Finally, the molten salt and water cascade energy storage system and the hot water storage and heat exchange system stop operating.

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