Combined energy storage coupling heat supply network frequency modulation auxiliary thermal power generating unit system and method

Abstract

The invention relates to the field of power grid frequency modulation, in particular to a combined energy storage coupling heat supply network frequency modulation auxiliary thermal power generating unit system and method. Comprising a scheduling control platform; one end of the steam turbine generator unit is connected with the dispatching control platform, and the other end of the steam turbine generator unit is connected with the steam supply mother pipe; and one end of the fused salt heat storage unit is connected with the dispatching control platform, and the other end of the fused salt heat storage unit is connected with the steam supply main pipe. Frequency modulation is carried out in the mode that fused salt energy storage and a heat supply network are combined, on one hand, a double fused salt electric heater does not need to be arranged according to frequency modulation power, the electric heater can participate in adjustment in a full-power mode, the engineering cost of a fused salt heat storage unit is reduced, and on the other hand, the problem that energy efficiency is reduced when the electric heater operates in an intermediate load for a long time is solved. During frequency modulation of the heat supply network, through steam self-balance supplement of the fused salt heat storage unit, steam supply stability during frequency modulation of the heat supply network is improved, steam supply pressure fluctuation cannot be caused, and the defects that the heat supply network cannot store energy and generates superheated steam are overcome.

Description

Technical Field

[0001] The present invention relates to the field of power grid frequency regulation, and in particular to a combined energy storage coupled thermal network frequency regulation auxiliary thermal power generation unit system and method. Background Art

[0002] Electricity is difficult to store on a large scale, and the grid dispatch center needs to always maintain the power generation load equal to the power consumption load. When the power generation load in the grid is greater than the power consumption load, the grid frequency increases, and vice versa. Therefore, the process of adjusting the power generation load according to the power consumption load is also called "frequency regulation."

[0003] There are many ways of frequency regulation in the prior art. For example, the Chinese patent application No. 201210304745.8 discloses a method of improving the primary frequency regulation capability of a heating unit by utilizing heat storage in a heat network pipeline. Specifically, a nonlinear filter is used to decompose the unit load command into two parts: a slowly changing steady-state load command and a rapidly changing transient load command. The steady-state load command is sent to the original unit coordinated control system, and the transient load command is divided into two paths. One path is superimposed on the heating steam extraction regulating butterfly valve opening command after passing through a first-order inertia link, and the other path is reversely superimposed on the unit power generation load signal after passing through a transfer function link of the regulating butterfly valve opening to the unit power generation load, and the superimposed signal is then used as the power generation load feedback signal of the original coordinated control system. The problem with the above patent is that the frequency modulation is carried out by utilizing the thermal hysteresis of the heating network, which requires a large scale of the heating network and is not applicable to thermal power units in small heating networks. In addition, the adjustable range of the heating network butterfly valve is limited. Excessive adjustment of the steam supply flow rate will cause serious fluctuations in the heat consumption of heat users. In addition, the regulation dead zone of this technology is during the grid downregulation process, that is, when the heating network is supplying steam at full load, the butterfly valve cannot be opened further, resulting in the inability to achieve grid downregulation.

[0004] For another example, the Chinese patent application number 202410345140.6 discloses a frequency regulation method and system for a molten salt energy storage coupled thermal power unit, which specifically discloses that the frequency regulation response demand of the power grid is decomposed by the VMD algorithm to obtain a residual component and multiple modal components; the adjacent aliasing degrees of all modal components are calculated, and the high-frequency modal component group and the low-frequency modal component group are divided based on the minimum value of the adjacent aliasing degree; if the high-frequency modal component group includes only one modal component, the residual component and the multiple modal components are evenly divided into a high-frequency group and a low-frequency group according to the center frequency, and a variety of fusion methods are used for the modal components in the high-frequency group to obtain different fusion components; the ratio of each fusion component to the frequency regulation response demand of the power grid is calculated to obtain a target ratio group and a target fusion component; the modal component in the high-frequency group corresponding to the target fusion component constitutes a high-frequency component, and the low-frequency group and the remaining modal components in the high-frequency group constitute a low-frequency component; so as to control the molten salt energy storage equipment and the thermal power unit to respond according to the high and low frequency components respectively. The above patent uses molten salt energy storage to modulate the frequency of thermal power units. The electric heater of molten salt energy storage needs to run in the intermediate load section all the time, which will lead to the phenomenon of high quality and low use of electric heating steam for a long time, resulting in reduced energy efficiency. In addition, for the power of the electric heater of molten salt energy storage, a load with double the frequency modulation capacity is required to meet the frequency modulation requirements, which requires a large investment. In addition, if the technology does not run in the intermediate load, its regulation dead zone is in the process of power grid regulation, that is, when the power of the electric heater is 0, the system has no ability to release energy, resulting in the inability to achieve power grid regulation. Summary of the invention

[0005] In response to the problems mentioned in the prior art, the present invention proposes a combined energy storage coupled heat network frequency regulation auxiliary thermal power unit system, which adopts a frequency regulation method combining molten salt energy storage and heat network, and utilizes the opposite characteristics of the dead zones of heat network frequency regulation and molten salt frequency regulation to perform coupled frequency regulation.

[0006] The combined energy storage coupled heat network frequency modulation auxiliary thermal power unit system of the present invention comprises:

[0007] Dispatch control platform;

[0008] Steam turbine generator set, one end of the steam turbine generator set is connected to the dispatching control platform, and the other end is connected to the steam supply main pipe;

[0009] The molten salt heat storage unit has one end connected to the dispatching control platform and the other end connected to the steam supply main pipe.

[0010] Preferably, the molten salt heat storage unit comprises a water supply system, a phase change heat storage unit connected to the water supply system, a high-temperature molten salt tank, a steam drum and a superheater;

[0011] The phase change thermal storage unit is connected to the high temperature molten salt tank;

[0012] One end of the drum is connected to the superheater, and the other end is connected to the phase change heat storage unit;

[0013] The superheater is connected to the phase change thermal storage unit and is also connected to the high-temperature molten salt tank.

[0014] Preferably, a heating component is provided in both the phase change thermal storage unit and the high temperature molten salt tank.

[0015] Preferably, a forced circulation pump is provided between the steam drum and the water supply system.

[0016] Preferably, a water regulating valve is provided between the water supply system and the phase change thermal storage unit.

[0017] Preferably, a pressure self-balancing check valve and a steam supply valve are sequentially arranged between the superheater and the steam supply main pipe according to the steam flow direction.

[0018] Preferably, the dispatching control platform includes an instruction receiving module, an analysis module, a calculation module, a dispatching control module and a pressure analysis module.

[0019] A method for a combined energy storage coupled heat network assisted thermal power generation unit system, comprising:

[0020] When the grid frequency regulation demand increases, the dispatch control platform analyzes the grid dispatch instructions and calls the heat network for frequency regulation. The heat network regulating valve is controlled to open and close according to the grid dispatch instructions. During the opening and closing process of the heat network regulating valve, the molten salt heat storage unit is used to supplement steam to achieve stable steam supply.

[0021] When the grid frequency regulation demand decreases, the steam supply valve is opened, the dispatching control platform analyzes the grid dispatching instructions and starts the phase change heat storage and heat conversion unit electric heating and increases the load. When the grid frequency regulation demand further decreases, the phase change heat storage and heat conversion unit electric heating power decreases, and at the same time, steam is supplemented to the molten salt heat storage unit to compensate for steam fluctuations when the grid frequency regulation demand increases.

[0022] Preferably, the steam supplement process is as follows: when steam fluctuation occurs in the main pipe of the heating network, the steam stored in the steam drum is heated by a heater and sent to the main pipe of the heating network for steam supplement, so as to achieve stable steam supply.

[0023] Preferably, when the steam in the drum is insufficient, the water supply system is started, and saturated steam is generated after heating by the phase change thermal storage unit and sent to the drum for storage; the high-temperature molten salt storage tank provides a heat source for the superheater.

[0024] Compared with the prior art, the present invention has achieved the following technical effects:

[0025] The present invention combines molten salt energy storage with the heat network for frequency modulation, which can make up for the shortcomings of the traditional technology of separate frequency modulation of the heat network and separate frequency modulation of molten salt energy storage. Compared with the traditional separate heat network frequency modulation, the present invention is suitable for any size of thermal power units during frequency modulation, has strong adaptability and multiple usage scenarios; secondly, the traditional heat network cannot store energy during frequency modulation, the present invention can store energy while supplying heat, and the stored heat energy is used to heat the steam, so as to obtain steam at a suitable temperature, avoiding equipment damage caused by overheated steam; in addition, the molten salt heat storage unit provided in the present invention can replenish steam in real time during frequency modulation, realize steam self-balancing, improve the steam supply stability during heat network frequency modulation, thereby reducing the steam supply pressure fluctuation caused by insufficient stability of traditional heat network frequency modulation, and further improve the heating experience of heat users.

[0026] Compared with the traditional single molten salt energy storage frequency modulation, the electric heater of the present invention does not need to be set with double load, because the steam turbine generator set can make up for the frequency modulation dead zone and frequency modulation demand, so the electric heater does not need to be set with double load for the frequency modulation capacity, which effectively reduces the engineering cost. On the other hand, the electric heater can be fully powered for regulation, avoiding the problem of reduced energy efficiency of the electric heater when running at intermediate load for a long time in traditional molten salt energy storage frequency modulation. BRIEF DESCRIPTION OF THE DRAWINGS

[0027] Figure 1 It is a schematic diagram of the system structure of the present invention;

[0028] Figure 2 It is the principle diagram of the present invention;

[0029] Figure 3 Schematic diagram of the method of the present invention.

[0030] Figure numerals: 1. Molten salt heat storage unit; 2. Heat network regulating valve; 3. Steam supply main pipe; 4. Steam turbine generator set; 5. Dispatching control platform; 6. Phase change heat storage unit; 7. High-temperature molten salt tank; 8. Superheater; 9. Steam drum; 10. Water supply system; 11. Pressure self-balancing check valve; 12. Steam supply valve; 13. Forced circulation pump; 14. Water flow regulating valve. DETAILED DESCRIPTION

[0031] Embodiments of the present application are described in detail below, and examples of the embodiments are shown in the accompanying drawings, wherein the same or similar reference numerals throughout represent the same or similar elements or elements with the same or similar functions. The embodiments described below with reference to the accompanying drawings are exemplary and are only used to explain the present application, and cannot be construed as limiting the present application. On the contrary, the embodiments of the present application include all changes, modifications and equivalents that fall within the spirit and connotation of the appended claims.

[0032] like Figure 1As shown, the combined energy storage coupled heat network frequency regulation auxiliary thermal power unit system of the present invention includes: a dispatching control platform 5; a steam turbine generator set 4, one end of the steam turbine generator set 4 is connected to the dispatching control platform 5, and the other end is connected to the steam supply mother pipe 3; a molten salt heat storage unit 1, one end of the molten salt heat storage unit 1 is connected to the dispatching control platform 5, and the other end is connected to the steam supply mother pipe 3.

[0033] In the existing technology, when the thermal hysteresis of the heating network is used for frequency regulation, the scale of the heating network needs to be large, and the thermal power units of small heating networks cannot be applied. In addition, the adjustable range of the heating network butterfly valve is limited. Excessive adjustment of the steam supply flow will cause serious fluctuations in the heat consumption of heat users. In addition, the regulation dead zone of this technology is during the grid downregulation process, that is, when the heating network is supplying steam at full load, the butterfly valve cannot be opened further, resulting in the inability to achieve grid downregulation.

[0034] When using molten salt energy storage to regulate the frequency of thermal power units, the electric heater of molten salt energy storage needs to run in the middle load section all the time, which will lead to the phenomenon of high quality and low use of electric heating steam for a long time, resulting in reduced energy efficiency. In addition, for the power of the electric heater of molten salt energy storage, a load with double the frequency regulation capacity is required to meet the frequency regulation requirements, which requires a large investment. In addition, if the technology does not run in the middle load, its regulation dead zone is in the process of power grid regulation, that is, when the power of the electric heater is 0, the system has no ability to release energy, resulting in the inability to achieve power grid regulation.

[0035] The present invention combines molten salt energy storage with the heat network for frequency modulation. On the one hand, there is no need to set up double molten salt electric heaters for frequency modulation power. The electric heaters can participate in the regulation at full power, which reduces the engineering cost of the molten salt heat storage unit. On the other hand, it solves the problem of reduced energy efficiency of the electric heater when it runs at intermediate load for a long time. When the heat network of the present invention is frequency modulated, the steam self-balancing supplement of the molten salt heat storage unit improves the steam supply stability during the frequency modulation of the heat network, so that it will not cause fluctuations in the steam supply pressure, and solves the disadvantages of the heat network being unable to store energy and produce superheated steam.

[0036] Figure 1 As shown, the molten salt heat storage unit 1 includes a water supply system 10, a phase change heat storage unit 6 connected to the water supply system 10, a high-temperature molten salt tank 7, a steam drum 9 and a superheater 8. The phase change heat storage unit 6 in the embodiment is an energy storage device based on phase change energy storage materials, which uses the property of a substance to absorb or release a large amount of latent heat during the phase change process to store and release heat. The heating component in the phase change heat storage unit 6 can heat the incoming water, and the incoming water generates high-temperature steam after being heated by the phase change heat storage unit 6, and the high-temperature steam is sent to the steam drum 9 for storage; the heating component in the embodiment is an electric heater.

[0037] In the embodiment, the phase change material of the phase change thermal storage unit 6 is preferably solid molten salt. The solid molten salt has a higher energy storage density and better thermal stability. The solid molten salt is a low-temperature salt in the phase change thermal storage unit 6. At this time, the low-temperature salt is heated by the heating component. Due to the difference in density, the liquid molten salt will move up, the solid molten salt will sink, and the volume will expand. The expanded liquid molten salt flows into the high-temperature molten salt tank 7 through a pipeline (by pumping) and is stored in the high-temperature molten salt tank 7. The high-temperature molten salt tank 7 can heat the superheater 8, and after the superheater 8 releases heat, the high-temperature molten salt becomes a low-temperature molten salt and is sent to the phase change thermal storage unit 6 for storage, thereby realizing the circulation of the molten salt between the phase change thermal storage unit 6 and the high-temperature molten salt tank 7.

[0038] In the embodiment, the purpose of the superheater 8 is to allow high-temperature and high-pressure steam to pass through the superheater 8 and perform heat exchange with the superheater 8, thereby further increasing the temperature of the steam; the superheater 8 is preferably a convection superheater 8, which uses the high-temperature molten salt tank 7 to provide a heat source, so that the steam temperature is increased to meet the quality requirements of the steam supply mother pipe 3, and is sent into the steam supply mother pipe 3 to achieve stable steam supply fluctuation pressure.

[0039] In the embodiment, a pressure self-balancing check valve 11 and a steam supply valve 12 are sequentially arranged between the superheater 8 and the steam supply main pipe 3 according to the steam flow direction. In order to ensure the safety, efficiency and stability of steam during the transmission process, valves are arranged at the connection between the superheater 8 and the steam supply main pipe 3, wherein the pressure self-balancing check valve 11 and the steam supply valve 12 are sequentially arranged according to the natural flow direction of steam; the pressure self-balancing check valve 11 has the function of automatically adjusting the steam flow direction and providing additional safety protection under specific conditions (such as pressure fluctuations). Specifically, when the pressure in the steam supply main pipe 3 drops instantaneously, the valve can quickly sense this change and can automatically open after detecting the pressure difference, thereby allowing the saturated steam from the steam drum 9 to pass quickly after being heated by the superheater 8. This process effectively alleviates the problem of unstable steam supply caused by the pressure drop of the steam supply main pipe 3, and can respond quickly in the face of emergencies such as pressure fluctuations, and ensure the stability and reliability of steam supply parameters by automatically adjusting the steam flow direction and heating process.

[0040] according to Figure 2 As shown, the steam supply valve 12 and the heat network regulating valve 2 are set to switch between heat network frequency regulation and molten salt heat storage frequency regulation according to the power grid frequency regulation demand. When the power grid frequency regulation demand increases, the heat network frequency regulation is adopted to adjust the opening of the heat network regulating valve 2 to achieve rapid regulation of the power grid load; when the power grid frequency regulation demand decreases, the molten salt heat storage frequency regulation is adopted to store heat energy during the low load period of the power grid by utilizing the high heat storage density and stability of the molten salt, and at the same time, it can also compensate for the steam fluctuation during the heat network frequency regulation.

[0041] In the embodiment, a forced circulation pump 13 is provided between the steam drum 9 and the water supply system 10, the purpose of which is to ensure that the steam water level in the steam drum 9 can be stably maintained within a predetermined normal range, because the water level in the steam drum 9 is directly related to the safe operation and efficiency of the entire system. Too high a water level may cause steam to carry water, thereby affecting the steam quality and damaging the equipment; too low a water level may cause dry burning, causing equipment damage or even safety accidents; therefore, a forced circulation pump 13 is introduced, the main function of which is to achieve active regulation of the water level of the steam drum 9 by increasing the flow rate and power of the water circulation. Specifically, when the dispatching control platform 5 detects that the water level in the steam drum 9 exceeds the set upper limit, the forced circulation pump 13 will be started to control the water level.

[0042] In the embodiment, a water flow regulating valve 14 is provided between the water supply system 10 and the phase change thermal storage unit 6. The water flow regulating valve 14 is a component connecting the water supply system 10 and the phase change thermal storage unit 6. Its main function is to dynamically adjust and control the water flow passing through according to the requirements of the scheduling control platform 5 or preset conditions, so as to realize precise water flow control between the water supply system 10 and the phase change thermal storage unit 6, thereby improving the thermal storage efficiency and system stability.

[0043] Implementation example Figure 1 As shown, the steam turbine generator set 4 converts the thermal energy of steam into mechanical energy, and then drives the generator to generate electrical energy, which can provide power support for the heating network. In this embodiment, when the heating network frequency modulation is adopted, the dispatching control platform 5 will calculate the amount of power that needs to be adjusted according to the grid dispatching instruction, and then change the flow and resistance characteristics of the heating network by adjusting the opening of the heating network regulating valve 2, thereby affecting the energy consumption of the heating equipment in the heating network, thereby achieving the purpose of frequency modulation.

[0044] The dispatch control platform 5 in the embodiment includes an instruction receiving module, an analysis module, a calculation module, a dispatch control module and a pressure analysis module. The instruction receiving module is used to receive power grid dispatch instructions.

[0045] Analysis module: Analyze the status of the electric heating in the heat network regulating valve 2 and the molten salt heat storage unit 1 in the system, and analyze whether the system is in a state of increasing or decreasing grid frequency regulation demand, or in the process of increasing grid frequency regulation demand to decreasing grid frequency regulation demand.

[0046] Operation module: Analyzes the amplitude that the operation system needs to adjust and converts the frequency-modulated power signal into executable valve opening and electric heater load signals.

[0047] Transportation control module: follow the target value through calling and controlling.

[0048] Pressure analysis module: detects the pressure fluctuation of the heat network in real time, uses the molten salt heat storage unit 1 to automatically stabilize the heat network, and starts the water supply system 10 in the molten salt heat storage unit 1 to produce new steam when the steam volume in the steam drum 9 is insufficient.

[0049] When using, Figure 3 As shown, when the grid frequency regulation demand increases, the dispatching control platform 5 analyzes the grid dispatching instructions and calls the heating network for frequency regulation, and uses the heating network regulating valve 2 to open and close to track the grid dispatching instructions. When the grid needs to be further improved, the heating network regulating valve 2 is closed. When the grid demand decreases, the heating network regulating valve 2 is fully opened. The steam supply fluctuations in the process of opening and closing the heating network regulating valve 2 are self-stabilized by the molten salt heat storage unit 1 to maintain stable steam supply.

[0050] When the grid frequency regulation demand decreases, the steam supply valve 12 is opened, and the dispatching control platform 5 analyzes the grid dispatching instructions, calls the phase change heat storage unit 6 and the electric heater in the high-temperature molten salt tank 7 to start and increase the load. When the grid frequency regulation demand further decreases, the power of the electric heater decreases. In this process, the molten salt heat storage unit 1 can be charged at the same time. When steam fluctuation occurs in the steam supply mother pipe 3, the steam stored in the steam drum 9 is heated to the steam quality required by the steam supply mother pipe 3 by the superheater 8 and then sent to the steam supply mother pipe 3 for steam supply, so as to realize the self-stabilization of the steam supply fluctuation pressure; when the steam stored in the steam drum 9 is insufficient, the water supply system 10 is started, and the saturated steam generated after being heated by the phase change heat storage unit 6 is sent to the steam drum 9 for storage. The heat source of the superheater 8 comes from the high-temperature molten salt storage tank. After heat release, the low-temperature salt in the high-temperature molten salt storage tank is sent to the phase change heat storage unit 6 for storage.

[0051] The embodiment specifically takes a 2x330MW coal-fired thermal power unit in a power plant as an example. The steam turbine is a 17.75 / 540 / 540 subcritical, one-time intermediate reheat, three-cylinder, two-exhaust, condensing steam turbine. After the heat supply transformation, steam can be extracted from the cold section and hot section of the steam turbine to supply heat to the outside. The heating steam capacity of the two units is designed to be 140T / h in total. The regulation capacity of the above two units is only 1%Pe / min, that is, a total regulation capacity of 6.6MW / min. By coupling the combined energy storage coupled heat network frequency modulation auxiliary thermal power unit system and method of the present invention, after the total capacity reaches 10MW, its regulation capacity is increased by nearly 2.5 times.

[0052] It should be noted that, in the description of this application, the terms "first", "second", etc. are only used for descriptive purposes and cannot be understood as indicating or implying relative importance. In addition, in the description of this application, unless otherwise specified, the meaning of "plurality" is two or more.

[0053] Any process or method description in a flowchart or otherwise described herein may be understood to represent a module, segment or portion of code that includes one or more executable instructions for implementing the steps of a specific logical function or process, and the scope of the preferred embodiments of the present application includes alternative implementations in which functions may not be performed in the order shown or discussed, including performing functions in a substantially simultaneous manner or in the reverse order depending on the functions involved, which should be understood by technicians in the technical field to which the embodiments of the present application belong.

[0054] In the description of this specification, the description with reference to the terms "one embodiment", "some embodiments", "example", "specific example", or "some examples" means that the specific features, structures, materials or characteristics described in conjunction with the embodiment or example are included in at least one embodiment or example of the present application. In this specification, the schematic representation of the above terms does not necessarily refer to the same embodiment or example. Moreover, the specific features, structures, materials or characteristics described may be combined in any one or more embodiments or examples in a suitable manner.

[0055] Although the embodiments of the present application have been shown and described above, it can be understood that the above embodiments are exemplary and cannot be understood as limitations on the present application. Ordinary technicians in this field can change, modify, replace and modify the above embodiments within the scope of the present application.

[0056] Embodiments of the present application are described in detail below, and examples of the embodiments are shown in the accompanying drawings, wherein the same or similar reference numerals throughout represent the same or similar elements or elements with the same or similar functions. The embodiments described below with reference to the accompanying drawings are exemplary and are only used to explain the present application, and cannot be construed as limiting the present application. On the contrary, the embodiments of the present application include all changes, modifications and equivalents that fall within the spirit and connotation of the appended claims.

[0057] The examples of the present application are described in detail below, and the examples of the examples are shown in the accompanying drawings, wherein the same or similar reference numerals throughout represent the same or similar elements or elements having the same or similar functions. The examples described below with reference to the accompanying drawings are exemplary and are intended to be used to explain the present application, and should not be construed as limiting the present application.

Claims

1. Combined energy storage coupled heat network frequency modulation auxiliary thermal power unit system, characterized in that: include: Dispatch control platform; Steam turbine generator set, one end of the steam turbine generator set is connected to the dispatching control platform, and the other end is connected to the steam supply main pipe; The molten salt heat storage unit has one end connected to the dispatching control platform and the other end connected to the steam supply main pipe.

2. According to claim 1, the combined energy storage coupled heat network frequency modulation auxiliary thermal power unit system is characterized in that: The molten salt heat storage unit includes a water supply system, a phase change heat storage unit connected to the water supply system, a high-temperature molten salt tank, a steam drum and a superheater; The phase change thermal storage unit is connected to the high temperature molten salt tank; One end of the drum is connected to the superheater, and the other end is connected to the phase change heat storage unit; The superheater is connected to the phase change thermal storage unit and is also connected to the high-temperature molten salt tank.

3. According to claim 2, the combined energy storage coupled thermal network frequency modulation auxiliary thermal power unit system is characterized in that: Heating components are provided in the phase change thermal storage unit and the high-temperature molten salt tank.

4. According to claim 3, the combined energy storage coupled thermal network frequency modulation auxiliary thermal power unit system is characterized in that: A forced circulation pump is provided between the steam drum and the water supply system.

5. According to claim 2, the combined energy storage coupled thermal network frequency modulation auxiliary thermal power unit system is characterized in that: A water regulating valve is provided between the water supply system and the phase change thermal storage unit.

6. According to claim 2, the combined energy storage coupled thermal network frequency modulation auxiliary thermal power unit system is characterized in that: A pressure self-balancing check valve and a steam supply valve are arranged between the superheater and the steam supply main pipe in sequence according to the steam flow direction.

7. According to claim 1, the combined energy storage coupled thermal network frequency modulation auxiliary thermal power unit system is characterized in that: The dispatching control platform includes an instruction receiving module, an analysis module, a calculation module, a dispatching control module and a pressure analysis module.

8. The method of the combined energy storage coupled heat network auxiliary thermal power unit system according to any one of claims 1 to 7, characterized in that: include: When the grid frequency regulation demand increases, the dispatch control platform analyzes the grid dispatch instructions and calls the heat network for frequency regulation. The heat network regulating valve is controlled to open and close according to the grid dispatch instructions. During the opening and closing process of the heat network regulating valve, the molten salt heat storage unit is used to supplement steam to achieve stable steam supply. When the grid frequency regulation demand decreases, the steam supply valve is opened, the dispatching control platform analyzes the grid dispatching instructions and starts the phase change heat storage and heat conversion unit electric heating and increases the load. When the grid frequency regulation demand further decreases, the phase change heat storage and heat conversion unit electric heating power decreases, and at the same time, steam is supplemented to the molten salt heat storage unit to compensate for steam fluctuations when the grid frequency regulation demand increases.

9. The method of combined energy storage coupled to thermal network frequency modulation to assist thermal power generation units according to claim 8, characterized in that: The steam supplement process is as follows: when steam fluctuation occurs in the main pipe of the heating network, the steam stored in the steam drum is heated by the heater and sent to the main pipe of the heating network for steam supplement to achieve stable steam supply.

10. The method of combined energy storage coupled to thermal network frequency modulation to assist thermal power generation units according to claim 9, characterized in that: When the steam in the drum is insufficient, the feed water system is started, and saturated steam is generated after being heated by the phase change thermal storage unit and sent to the drum for storage; the high-temperature molten salt storage tank provides a heat source for the superheater.

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