Thermal power configuration optical storage frequency modulation method and system based on direct current networking

Abstract

The invention discloses a thermal power configuration light storage frequency modulation method and system based on direct current networking, and relates to the technical field of power distribution network optimization, and the method comprises the steps: building a thermal power configuration light storage subsection combined direct current power supply system; a photovoltaic maximum load shedding rate is set, and a part of power instructions exceeding a photovoltaic frequency modulation capability range are distributed to an energy storage system for response; and proposing two frequency modulation effect evaluation indexes according to the frequency adjustment range, and performing effect evaluation on the frequency modulation of the photovoltaic energy storage auxiliary thermal power generating unit. A thermal power configuration photovoltaic and energy storage access thermal power low-voltage system is constructed to form a light-storage integrated system, a photovoltaic energy storage system is accessed to plant power of a thermal power generating unit, light-storage combination assists frequency modulation of the thermal power generating unit while the power utilization rate of a thermal power plant is reduced, and part of power instructions exceeding the photovoltaic frequency modulation capacity range are distributed to energy storage response. Photovoltaic and energy storage are matched to assist the thermal power generating unit in frequency modulation, photovoltaic power generation benefits can be guaranteed, the thermal power generating unit can be assisted in frequency modulation, and more benefits can be obtained.

Description

Technical Field

[0001] The present invention relates to the technical field of distribution network optimization, and particularly to a thermal power configuration optical storage frequency modulation method and system based on DC networking. Background Art

[0002] At present, the typical design of the auxiliary power system of large thermal power units is to connect a step-down transformer through a tap at the generator outlet, which can be divided into two levels of voltage transformation. One level is to step down from 20 kV at the generator outlet to 6 kV, and the other level is to step down from 6 kV to 400 V. All use power frequency transformers and involve alternating current. As the capacity of the unit continues to increase, the capacity of the auxiliary power system also continues to increase. The capacity of the high-voltage auxiliary transformer becomes larger, and the short-circuit current of the auxiliary power system is very large, which puts higher requirements on the short-circuit breaking capacity of high-voltage switches. To meet the requirements of short-circuit thermal stability, high-voltage cables in the auxiliary power system need to select thicker cables, increasing the investment cost. Traditional high-voltage auxiliary transformers use power frequency transformers, which are huge in volume. And in order to obtain a larger capacity of the auxiliary power system, capacity expansion and transformation are often carried out, with huge transformation costs and long construction periods, delaying the normal power generation of the power plant.

[0003] Adopting the form of DC networking in the auxiliary power system can effectively solve some bottleneck problems in the development of traditional AC auxiliary power systems. Compared with traditional AC auxiliary power systems, the form of DC networking has many advantages: the power supply capacity of DC networking is larger; DC networking does not need to consider phase angle and frequency, and can realize the interconnection of asynchronous systems. Auxiliary loads are connected to the DC auxiliary power system through rectifier devices, which can improve the power conversion efficiency, reduce equipment losses, realize load frequency conversion drive, simplify the internal circuit of the load, and reduce the failure rate and equipment cost. Summary of the Invention

[0004] In view of the above existing problems, the present invention is proposed.

[0005] Therefore, the technical problem solved by the present invention is: how to ensure a large power supply capacity while improving the power conversion efficiency, reducing equipment losses, realizing load frequency conversion drive, simplifying the internal circuit of the load, and reducing the failure rate and equipment cost.

[0006] To solve the above technical problems, the present invention provides the following technical solution: a thermal power configuration optical storage frequency modulation method based on DC networking, including: establishing a thermal power configuration optical storage segmented combined DC power supply system; setting the maximum PV load shedding rate, and distributing the part of the power command that exceeds the PV frequency modulation capacity range to the energy storage system for response; proposing two types of frequency modulation effect evaluation indicators according to the frequency regulation range, and evaluating the effect of PV energy storage assisting thermal power units in frequency modulation.

[0007] As a preferred embodiment of the method for configuring a thermal power plant with optical storage for frequency modulation based on DC networking according to the present invention, wherein: the thermal power plant configured with optical storage segmented combined DC power supply system includes configuring a photovoltaic power generation system and an energy storage system to access the low-voltage system of the thermal power plant. The configured photovoltaic power generation system of the thermal power plant includes connecting the 400V bus of the photovoltaic power generation system and the 400V bus of the energy storage system through an interconnection breaker to form an integrated optical storage system. The photovoltaic panels are networked in AC through an inverter, and the energy storage modules are connected to the grid in AC through a converter. The photovoltaic panels and the energy storage modules are connected to the 220V DC power supply bus of the thermal power plant through a DC-DC converter device. The energy storage system accessing the low-voltage system of the thermal power plant includes connecting the photovoltaic energy storage system to the auxiliary power of the thermal power unit.

[0008] As a preferred embodiment of the method for configuring a thermal power plant with optical storage for frequency modulation based on DC networking according to the present invention, wherein: after the power command is allocated, the power adjustment amount of the frequency modulation command allocated to the photovoltaic power generation system and the energy storage system under the coupling of the optical storage is obtained, which is expressed as:

[0009]

[0010] where, ΔP pv_c is the power adjustment amount of the frequency modulation command allocated to the photovoltaic power generation system; ΔP b_c is the power adjustment amount of the frequency modulation command allocated to the energy storage system; ΔP pv is the power adjustment amount of the photovoltaic droop control; P res is the reserved power spare capacity of the photovoltaic power generation; Δf is the frequency adjustment amount of the thermal power unit; ΔP b is the power adjustment amount of the energy storage droop control; P B is the rated power of the energy storage.

[0011] As a preferred embodiment of the method for configuring a thermal power plant with optical storage for frequency modulation based on DC networking according to the present invention, wherein: the objects of the effect evaluation include the step load fluctuation of the thermal power plant and the random continuous load fluctuation of the thermal power plant. When it is the step load fluctuation of the thermal power plant, the frequency modulation evaluation indexes are: the absolute value of the maximum dynamic frequency deviation |Δf m |, the absolute value of the steady-state frequency deviation |Δf s |, the adjustment time t s , |Δf m |, |Δf s |. The smaller |Δf s | is, the more significant the frequency modulation effect is, and the smaller t s is, the faster the frequency modulation response is;

[0012] When it is the random continuous load fluctuation of the thermal power plant, the frequency peak-to-valley difference Δf p_v and the root mean square frequency f RMS are used to evaluate the frequency modulation performance of the auxiliary power optical storage system. The frequency peak-to-valley difference Δf p_v and the root mean square frequency f RMS respectively reflect the frequency stability and the degree of dispersion from the reference value, which are expressed as:

[0013]

[0014] wherein, f max and f min are the maximum and minimum frequencies respectively; n is the number of sampling points; f i is the value of the frequency at the sampling point i; the smaller f RMS is, the better the frequency regulation effect of the photovoltaic energy storage assisted thermal power unit is.

[0015] In a second aspect, another object of the present invention is to provide a thermal power configuration photovoltaic energy storage frequency modulation system based on DC networking, including: a thermal power 400V bus unit, a photovoltaic energy storage grid-connected access DC power converter unit, and a photovoltaic energy storage battery unit; the thermal power 400V bus unit is connected to the 400V low-voltage plant system for providing a unified access point for photovoltaic and energy storage to access the thermal power low-voltage system; the photovoltaic energy storage grid-connected access DC power converter unit is used for realizing the frequency stability of the system by reasonably coordinating the responses of photovoltaic and energy storage when assisting the thermal power unit in frequency modulation; the photovoltaic energy storage battery unit is used for supplying power to the 220V DC security power supply.

[0016] As a preferred solution of the thermal power configuration photovoltaic energy storage frequency modulation system based on DC networking according to the present invention, wherein: the thermal power 400V bus unit includes a 400V photovoltaic bus, a 400V energy storage bus, a 400V plant bus, a first interconnection circuit breaker, a second interconnection circuit breaker, and a DC power grid-connected switch;

[0017] The 400V photovoltaic bus and the 400V energy storage bus are connected through the first interconnection circuit breaker, and the 400V energy storage bus and the 400V plant bus are connected through the second interconnection circuit breaker to form a low-voltage side access point of the photovoltaic energy storage integrated system and are connected to the 400V low-voltage plant system.

[0018] As a preferred solution of the thermal power configuration photovoltaic energy storage frequency modulation system based on DC networking according to the present invention, wherein: the photovoltaic energy storage grid-connected access DC power converter unit includes a photovoltaic inverter, a photovoltaic grid-connected switch, an energy storage converter, an energy storage grid-connected switch, a DC power inverter device, a 220V DC power bus, an energy storage backup DC-DC converter, and a photovoltaic backup DC-DC converter;

[0019] The photovoltaic inverter is connected to the 400V photovoltaic bus through the photovoltaic grid-connected switch, the energy storage converter is connected to the 400V energy storage bus through the energy storage grid-connected switch, and the 220V DC power bus is connected to the 400V plant bus through the DC power inverter device and the DC power grid-connected switch.

[0020] As a preferred solution of the thermal power configuration optical storage frequency modulation system based on DC networking according to the present invention, wherein: the photovoltaic energy storage battery unit includes a photovoltaic panel, an energy storage module and a DC battery. The photovoltaic panel is connected to the 220V DC power bus through a photovoltaic backup DC-DC converter. The energy storage module is connected to the 220V DC power bus through an energy storage backup DC-DC converter. The DC battery is connected to the 220V DC power bus.

[0021] In a third aspect, a computer device includes a memory and a processor. The memory stores a computer program. When the processor executes the computer program, the steps of the above-mentioned thermal power configuration optical storage frequency modulation method based on DC networking are implemented.

[0022] In a fourth aspect, a computer-readable storage medium stores a computer program. When the computer program is executed by a processor, the steps of the above-mentioned thermal power configuration optical storage frequency modulation method based on DC networking are implemented.

[0023] Advantages of the present invention: The thermal power configuration optical storage frequency modulation method and system based on DC networking according to the present invention construct a thermal power configuration with photovoltaic and energy storage connected to the low-voltage system of thermal power. The 400V bus of the photovoltaic and the 400C bus of the energy storage are connected through an interconnection breaker to form an integrated optical storage system. The photovoltaic panel realizes AC networking through an inverter, and the energy storage module is connected to the AC grid through a converter. The photovoltaic panel and the energy storage module are also connected to the 220V DC power bus of thermal power through a DC-DC conversion device, which can be used as a backup system for the DC power supply of thermal power to supply power to the 220V DC security power supply, improve the power supply reliability of the DC power supply system, and extend the power supply duration of the 220V DC security power supply. The photovoltaic energy storage system is connected to the auxiliary power of the thermal power unit, which can reduce the auxiliary power rate of the thermal power plant. It can also jointly assist the thermal power unit in frequency modulation by the optical storage. The part of the power command beyond the frequency modulation capacity range of the photovoltaic is allocated to the energy storage for response, realizing the cooperation between the photovoltaic and the energy storage to assist the thermal power unit in frequency modulation. It can ensure the photovoltaic power generation income while assisting the thermal power unit in frequency regulation to obtain more income. Description of the Drawings

[0024] In order to more clearly illustrate the technical solutions of the embodiments of the present invention, the drawings required for the description of the embodiments will be briefly introduced below. Obviously, the drawings in the following description are only some embodiments of the present invention. For those of ordinary skill in the art, other drawings can be obtained based on these drawings without creative efforts.

[0025] Figure 1 It is the overall flowchart of a thermal power configuration optical storage frequency modulation method based on DC networking provided by an embodiment of the present invention;

[0026] Figure 2Schematic diagram of a thermal power configuration optical storage frequency modulation system based on DC networking provided by an embodiment of the present invention. Detailed implementation manners

[0027] To make the above objects, features, and advantages of the present invention more apparent and understandable, the following provides a detailed description of the specific implementation manners of the present invention with reference to the accompanying drawings of the specification. Obviously, the described embodiments are part of the embodiments of the present invention, rather than all embodiments. All other embodiments obtained by those of ordinary skill in the art based on the embodiments of the present invention without creative efforts shall fall within the protection scope of the present invention.

[0028] In the following description, many specific details are set forth to facilitate a full understanding of the present invention. However, the present invention may also be implemented in other ways different from those described herein. Those skilled in the art can make similar generalizations without departing from the connotation of the present invention. Therefore, the present invention is not limited by the specific embodiments disclosed below.

[0029] Embodiment 1

[0030] Referring to Figure 1 , an embodiment of the present invention provides a thermal power configuration optical storage frequency modulation method based on DC networking, including:

[0031] S1: Establish a thermal power configuration optical storage segmented combined DC power supply system;

[0032] Furthermore, configure a photovoltaic and energy storage system to access the low-voltage system of the thermal power plant. The configuration of the photovoltaic and energy storage system for the thermal power plant includes connecting the 400V bus of the photovoltaic and the 400C bus of the energy storage through an interconnection circuit breaker to form an integrated optical storage system. The photovoltaic panels are connected to the AC network through an inverter, and the energy storage modules are connected to the AC grid through a converter. The photovoltaic panels and the energy storage modules are connected to the 220V DC power supply bus of the thermal power plant through a DC-DC converter device. The connection of the energy storage to the low-voltage system of the thermal power plant includes connecting the photovoltaic energy storage system to the auxiliary power of the thermal power unit.

[0033] S2: Set the maximum load reduction rate of the photovoltaic, and allocate the power commands exceeding the frequency modulation capacity range of the photovoltaic to the energy storage system for response;

[0034] Furthermore, configure a photovoltaic in the auxiliary power of the thermal power plant to enable the photovoltaic to participate in the frequency modulation of the thermal power unit. The existing strategy is to adopt a load reduction control method in the control system of the photovoltaic inverter. Its essence is to make the photovoltaic array deviate from the MPPT operation, so as to reserve a certain power margin for frequency regulation. This control method sacrifices part of the photovoltaic power generation benefit in exchange for the ability of the photovoltaic system to assist the thermal power unit in frequency modulation. Therefore, considering the economic benefits of the photovoltaic system and the frequency stability of the unit, it is necessary to reasonably set the photovoltaic load reduction rate.

[0035] In order to make full use of the high-power and high-frequency charge and discharge characteristics of the plant energy storage, on the premise of reasonably setting the maximum PV load shedding rate, the part of the power command beyond the PV frequency regulation capacity range is allocated to the energy storage system for response. The power regulation amounts of the PV and energy storage for the frequency regulation command under the PV-storage coupling are as follows:

[0036]

[0037] In the formula: ΔP pv_c is the power regulation amount of the PV for the frequency regulation command; ΔP b_c is the power regulation amount of the energy storage for the frequency regulation command; ΔP pv is the power regulation amount of the PV droop control; P res is the reserved power spare capacity of the PV power generation; Δf is the frequency regulation amount of the thermal power unit; ΔP b is the power regulation amount of the energy storage droop control; P B is the rated power of the energy storage.

[0038] S3: According to the frequency regulation range, two types of frequency regulation effect evaluation indexes are proposed to evaluate the effect of the PV energy storage assisting the thermal power unit for frequency regulation.

[0039] Furthermore, according to the frequency regulation range, two types of frequency regulation effect evaluation indexes are proposed to evaluate the effect of the PV energy storage assisting the thermal power unit for frequency regulation.

[0040] 1) For the step load fluctuation of the thermal power, the frequency regulation evaluation indexes are: the absolute value of the maximum dynamic frequency deviation |Δf m |, the absolute value of the steady-state frequency deviation |Δf s |, and the regulation time t s . Among them, the smaller |Δf m | and |Δf s | are, the more significant the frequency regulation effect is, and the smaller t s is, the faster the frequency regulation response is.

[0041] 2) For the random continuous load fluctuation of the thermal power, the frequency peak-to-valley difference Δf p_v and the root mean square of frequency f RMS are used to evaluate the frequency regulation performance of the plant PV energy storage system. The frequency peak-to-valley difference Δf p_v and the root mean square of frequency f RMS respectively reflect the frequency stability and the degree of dispersion from the reference value. It can be expressed as:

[0042]

[0043] In the formula, f max , f min are the maximum and minimum values of the frequency respectively; n is the number of sampling points; f i is the value of the frequency at the sampling point i. f RMSThe smaller it is, the better the frequency regulation effect of the photovoltaic energy storage assisted thermal power unit is indicated.

[0044] Embodiment 2

[0045] This is an embodiment of the present invention, which provides a thermal power configuration photovoltaic energy storage frequency modulation system based on DC networking, including: a thermal power 400V bus unit 1, a photovoltaic energy storage grid-connected access DC power converter unit 2, and a photovoltaic energy storage battery unit 3;

[0046] The thermal power 400V bus unit 1 is connected to the 400V low-voltage industrial power system, and is used to provide a unified access point for photovoltaic and energy storage to access the thermal power low-voltage system; the thermal power 400V bus unit 1 includes a 400V photovoltaic bus 1-1, a 400V energy storage bus 1-3, a 400V industrial bus 1-5, a first interconnection circuit breaker 1-2, a second interconnection circuit breaker 1-4, and a DC power grid-connected switch 1-6;

[0047] The 400V photovoltaic bus 1-1 and the 400V energy storage bus 1-3 are connected through the first interconnection circuit breaker 1-2, and the 400V energy storage bus 1-3 and the 400V industrial bus 1-5 are connected through the second interconnection circuit breaker 1-4 to form a low-voltage side access point of the photovoltaic energy storage integrated system and are connected to the 400V low-voltage industrial power system

[0048] The photovoltaic energy storage grid-connected access DC power converter unit 2 is used to achieve the frequency stability of the system by reasonably allocating the responses of photovoltaic and energy storage when assisting the thermal power unit in frequency modulation; the photovoltaic energy storage grid-connected access DC power converter unit 2 includes a photovoltaic inverter 2-2, a photovoltaic grid-connected switch 2-1, an energy storage converter 2-4, an energy storage grid-connected switch 2-3, a DC power inverter device 2-5, a 220V DC power bus 2-6, an energy storage backup DC-DC converter 2-7, and a photovoltaic backup DC-DC converter 2-8;

[0049] The photovoltaic inverter 2-2 is connected to the 400V photovoltaic bus 1-1 through the photovoltaic grid-connected switch 2-1, the energy storage converter 2-3 is connected to the 400V energy storage bus 1-3 through the energy storage grid-connected switch 2-3, and the 220V DC power bus 2-6 is connected to the 400V industrial bus 1-5 through the DC power inverter device 2-5 and the DC power grid-connected switch 1-6.

[0050] The photovoltaic energy storage battery unit 3 is used to supply power to the 220V DC security power supply.

[0051] The photovoltaic energy storage battery unit 3 includes a photovoltaic panel 3-1, an energy storage module 3-2, and a DC battery 3-3. The photovoltaic panel 3-1 is connected to the 220V DC power bus 2-6 through a photovoltaic backup DC-DC converter 2-8. The energy storage module 3-2 is connected to the 220V DC power bus 2-6 through an energy storage backup DC-DC converter 2-7. The DC battery 3-3 is connected to the 220V DC power bus 2-6.

[0052] When photovoltaic energy storage is needed to supply power to the 220V DC power bus, the photovoltaic and energy storage backup DC-DC converters are turned on, while the photovoltaic inverter and the energy storage converter are turned off. By using power electronic components, circuit breakers can be dispensed with, further saving investment.

[0053] Photovoltaic grid connection switch 2-1 and energy storage grid connection switch 2-3: Control whether the photovoltaic and energy storage are connected to the 400V bus for AC networking. The opening and closing of the switches may be automatically determined by the control systems of the photovoltaic inverter and the energy storage converter according to grid demands and system status, or may be manually controlled.

[0054] DC power grid connection switch 1-6: Control whether the 220V DC power bus is connected to the 400V plant bus through a DC power inverter device. Its opening and closing may be automatically determined by the control system of the DC power system according to the DC bus voltage and load demands.

[0055] Interconnection circuit breakers 1-2, 1-4: As the main switches of the integrated photovoltaic and energy storage system, control whether the photovoltaic and energy storage are connected to the 400V low-voltage plant system as a whole. The opening and closing of the switches may be automatically determined by the electrical control system of the thermal power plant according to system stability and load demands, or may be manually controlled.

[0056] Photovoltaic backup DC-DC converter 2-8 and energy storage backup DC-DC converter 2-7: Turn on when photovoltaic energy storage is needed to supply power to the 220V DC power bus, while the photovoltaic inverter 2-2 and the energy storage converter 2-4 are turned off. The opening and closing of the switches may be automatically determined by the control system of the DC power system according to the DC bus voltage and load demands, or may be manually controlled.

[0057] Linkage between circuits:

[0058] When the photovoltaic or energy storage needs to be connected to the 400V bus for AC networking, the corresponding grid connection switch 2-2 or 2-4 will close, while the DC power grid connection switch 2-6 may remain open to avoid direct connection between the DC and AC systems.

[0059] When the PV energy storage is required to supply power to the 220V DC power bus, the PV backup DC-DC converter 2-8 and the energy storage backup DC-DC converter 2-7 will conduct, while the PV inverter 2-1 and the energy storage converter 2-3 will disconnect to ensure the stability and safety of the DC power system.

[0060] The opening and closing of the interconnection breaker 1-3 may have an interlock relationship with other switches. For example, when the entire PV energy storage integrated system needs to exit the operation, the interconnection breaker will disconnect.

[0061] Embodiment 3

[0062] An embodiment of the present invention, which is different from the previous two embodiments, is as follows:

[0063] If the described function is implemented in the form of a software functional unit and sold or used as an independent product, it can be stored in a computer-readable storage medium. Based on such an understanding, the technical solution of the present invention, in essence, or the part that contributes to the prior art, or a part of this technical solution, can be embodied in the form of a software product. This computer software product is stored in a storage medium and includes several instructions for causing a computer device (which may be a personal computer, a server, or a network device, etc.) to execute all or part of the steps of the methods described in various embodiments of the present invention. The foregoing storage medium includes: USB flash drives, mobile hard disks, read-only memories (ROM, Read-Only Memory), random access memories (RAM, Random Access Memory), magnetic disks, or optical disks, etc., which can store program codes.

[0064] The logic and / or steps represented in the flowchart or described in other ways herein, for example, can be considered as a definite sequence list of executable instructions for implementing logical functions, and can be specifically implemented in any computer-readable medium for use by an instruction execution system, apparatus, or device (such as a computer-based system, a system including a processor, or other systems that can fetch and execute instructions from the instruction execution system, apparatus, or device), or in combination with these instruction execution systems, apparatus, or devices. For the purposes of this specification, a "computer-readable medium" can be any device that can contain, store, communicate, propagate, or transport a program for use by or in connection with an instruction execution system, apparatus, or device.

[0065] More specific examples (a non-exhaustive list) of computer-readable media include the following: electrical connections (electronic devices) having one or more wirings, portable computer diskettes (magnetic devices), random access memory (RAM), read-only memory (ROM), erasable programmable read-only memory (EPROM or flash memory), optical fiber devices, and portable compact disc read-only memory (CDROM). Additionally, the computer-readable media can even be paper or other suitable media on which the program can be printed, since the program can be obtained electronically, for example, by optically scanning the paper or other media, followed by editing, interpretation, or other suitable processing as necessary, and then stored in a computer memory.

[0066] It should be understood that various parts of the present invention can be implemented by hardware, software, firmware, or a combination thereof. In the above embodiments, multiple steps or methods can be implemented by software or firmware stored in a memory and executed by a suitable instruction execution system. For example, if implemented in hardware, as in another embodiment, any one or a combination of the following techniques well known in the art can be used: discrete logic circuits having logic gate circuits for implementing logical functions on data signals, application specific integrated circuits having appropriate combinational logic gate circuits, programmable gate arrays (PGAs), field programmable gate arrays (FPGAs), etc.

[0067] It should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention and not to limit them. Although the present invention has been described in detail with reference to the preferred embodiments, those of ordinary skill in the art should understand that the technical solutions of the present invention can be modified or equivalently replaced without departing from the spirit and scope of the technical solutions of the present invention, and they should all be covered within the scope of the claims of the present invention.

Claims

1. A method for frequency modulation of thermal power generation with photovoltaic storage based on DC networking, characterized in that: include: Establish a thermal power configuration, photovoltaic and storage segmented joint DC power supply system; Set the maximum PV load reduction rate to allocate power instructions that exceed the PV frequency regulation capability to the energy storage system for response; According to the frequency regulation range, two types of frequency regulation effect evaluation indicators are proposed to evaluate the frequency regulation effect of photovoltaic energy storage assisted thermal power units.

2. The method for frequency modulation of thermal power generation with photovoltaic energy storage based on DC networking according to claim 1, characterized in that: The thermal power generation configuration photovoltaic storage segmented joint DC power supply system includes constructing thermal power generation configuration photovoltaic and energy storage access to the thermal power low-voltage system. The construction of thermal power generation configuration photovoltaic includes connecting the photovoltaic 400V bus and the energy storage 400C bus through an interconnecting circuit breaker to form an integrated photovoltaic storage system. The photovoltaic panels realize AC networking through an inverter, and the energy storage module is connected to the AC grid through a converter. The photovoltaic panels and the energy storage modules are connected to the thermal power 220V DC power bus through a DC-DC converter. The energy storage access to the thermal power low-voltage system includes connecting the photovoltaic energy storage system to the thermal power plant power supply.

3. The method for frequency modulation of thermal power generation with photovoltaic energy storage based on DC networking according to claim 1, characterized in that: After the power command allocation is performed, the power adjustment amount of the photovoltaic and energy storage allocation frequency modulation command under the photovoltaic-storage coupling is obtained, which is expressed as: Among them, ΔP pv_c Allocate frequency modulation command power adjustment amount for photovoltaic; ΔP b_c Allocate frequency modulation command power adjustment amount for energy storage; ΔP pv P is the photovoltaic droop control power regulation amount; res Reserve power reserve capacity for photovoltaic power generation; Δf is the frequency adjustment of thermal power units; ΔP b P is the power regulation value for energy storage droop control; B is the energy storage rated power.

4. The method for frequency modulation of thermal power generation with photovoltaic energy storage based on DC networking according to claim 3 is characterized in that: The objects of the effect evaluation include thermal power step load fluctuation and thermal power random continuous load fluctuation. When it is thermal power step load fluctuation, the frequency regulation evaluation index is: the absolute value of the maximum dynamic frequency deviation |Δf m |, Steady-state frequency deviation absolute value |Δf s |、Adjustment time t s , |Δf m |,|Δf s The smaller the |, the more significant the frequency modulation effect is. s The smaller it is, the faster the FM response is; When the thermal power random continuous load fluctuation occurs, the frequency peak-to-valley difference Δf is used. p_v and the frequency RMS f RMS Evaluate the frequency modulation performance of the solar energy storage system used in the factory, the frequency peak-to-valley difference Δf p_v and the frequency RMS f RMS Respectively reflect the frequency stability and the degree of dispersion from the reference value, expressed as: Among them, f max 、f min are the maximum and minimum frequency respectively; n is the number of sampling points; f i is the value of the frequency at sampling point i; f RMS The smaller it is, the better the frequency regulation effect of photovoltaic energy storage in assisting thermal power units is.

5. A system using the method for frequency modulation of thermal power generation with photovoltaic storage based on DC networking as claimed in any one of claims 1 to 4, characterized in that: include: A thermal power 400V busbar unit (1), a photovoltaic energy storage grid-connected DC power supply conversion unit (2), and a photovoltaic energy storage battery unit (3); The thermal power 400V busbar unit (1) is connected to a 400V low-voltage plant system, and is used to provide a unified access point for photovoltaic and energy storage to access the thermal power low-voltage system; The photovoltaic energy storage grid-connected DC power supply conversion unit (2) is used to achieve system frequency stability by reasonably allocating photovoltaic and energy storage responses when assisting the thermal power unit in frequency regulation; The photovoltaic energy storage battery unit (3) is used to provide power for the 220V DC security power supply.

6. The thermal power configuration photovoltaic storage frequency modulation system based on DC networking as claimed in claim 5 is characterized by: The thermal power 400V bus unit (1) comprises a 400V photovoltaic bus (1-1), a 400V energy storage bus (1-3), a 400V plant bus (1-5), a first interconnection circuit breaker (1-2), a second interconnection circuit breaker (1-4) and a DC power grid-connected switch (1-6); The 400V photovoltaic bus (1-1) and the 400V energy storage bus (1-3) are connected via a first interconnecting circuit breaker (1-2), and the 400V energy storage bus (1-3) and the 400V plant bus (1-5) are connected via a second interconnecting circuit breaker (1-4), thereby forming a low-voltage side access point of the photovoltaic and energy storage integrated system and connecting to a 400V low-voltage plant system.

7. The thermal power configuration photovoltaic storage frequency modulation system based on DC networking according to claim 6 is characterized by: The photovoltaic energy storage grid-connected DC power supply conversion unit (2) comprises a photovoltaic inverter (2-2), a photovoltaic grid-connected switch (2-1), an energy storage converter (2-4), an energy storage grid-connected switch (2-3), a DC power supply inverter (2-5), a 220V DC power supply bus (2-6), an energy storage backup DC-DC converter (2-7), and a photovoltaic backup DC-DC converter (2-8); The photovoltaic inverter (2-2) is connected to the 400V photovoltaic bus (1-1) via the photovoltaic grid-connected switch (2-1), the energy storage converter (2-4) is connected to the 400V energy storage bus (1-3) via the energy storage grid-connected switch (2-3), and the 220V DC power bus (2-6) is connected to the 400V factory bus (1-5) via the DC power inverter device (2-5) and the DC power grid-connected switch (1-6).

8. The thermal power configuration photovoltaic storage frequency modulation system based on DC networking according to claim 6 is characterized by: The photovoltaic energy storage battery unit (3) comprises a photovoltaic panel (3-1), an energy storage module (3-2) and a DC battery (3-3); the photovoltaic panel (3-1) is connected to a 220V DC power bus (2-6) via a photovoltaic backup DC-DC converter (2-8); the energy storage module (3-2) is connected to the 220V DC power bus (2-6) via an energy storage backup DC-DC converter (2-7); and the DC battery (3-3) is connected to the 220V DC power bus (2-6).

9. A computer device comprising a memory and a processor, wherein the memory stores a computer program, wherein: When the processor executes the computer program, the steps of the method for frequency modulation of thermal power generation configured with photovoltaic energy storage based on DC networking according to any one of claims 1 to 4 are implemented.

10. A computer-readable storage medium having a computer program stored thereon, characterized in that: When the computer program is executed by the processor, the steps of the method for frequency modulation of thermal power generation configured with photovoltaic energy storage based on DC networking according to any one of claims 1 to 4 are implemented.

Images