Thermal power configuration optical storage backup combined standby transformer starting and standby transformer starting method and system

Abstract

The invention discloses a thermal power configuration light storage and backup combined starting and backup transformer method and system, and relates to the technical field of power distribution network optimization, and the method comprises the steps: arranging a distributed photovoltaic energy storage system in a power utilization system of a thermal power plant; a fundamental wave injection method control strategy is adopted, and a proper amount of fundamental waves are introduced into a modulation wave calculation link; and a photovoltaic inverter thyristor modulation voltage is adjusted by adopting a fundamental wave compensation method. According to the invention, the distributed photovoltaic energy storage system is configured at a thermal power 6kV station section, the distributed photovoltaic energy storage system is connected to the low-voltage side of the thermal power standby transformer and plays a role in serving as a standby power supply of the standby transformer, when station power needs to be supplied by the standby transformer, the distributed photovoltaic energy storage system supplies power at the same time, and on the basis of reducing electric energy consumed by the standby transformer power supply, the distributed photovoltaic energy storage system can be used as a standby power supply of the standby transformer. The power supply reliability can be improved, a fundamental wave injection method control strategy is adopted, a proper amount of fundamental waves are introduced into a modulation wave calculation link, and stable operation of the plant photovoltaic inverter under the power imbalance condition is achieved.

Description

Technical Field

[0001] The present invention relates to the technical field of distribution network optimization, and particularly to a method and system for configuring a photovoltaic energy storage backup combined startup and standby transformer for thermal power generation. Background Art

[0002] Currently, the typical design of the auxiliary power system of large thermal power units is to connect a step-down transformer by tapping from 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 unit capacity 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, the high-voltage cables of 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 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 a DC networking form 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 DC networking form 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 variable-frequency drive of loads, simplify the internal circuit of loads, 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 achieve the stable operation of the auxiliary photovoltaic inverter under power imbalance conditions and solve the problem of excessive distortion rate of the output current of the auxiliary photovoltaic inverter caused by input power imbalance.

[0006] To solve the above technical problem, the present invention provides the following technical solution: a method for configuring a photovoltaic energy storage backup combined startup and standby transformer for thermal power generation, including: arranging a distributed photovoltaic energy storage system in the thermal power plant auxiliary power system; adopting a fundamental wave injection method control strategy to introduce an appropriate amount of fundamental wave into the modulation wave calculation link; and adopting a fundamental wave compensation method to adjust the thyristor modulation voltage of the photovoltaic inverter.

[0007] As a preferred scheme of the method for configuring a photovoltaic energy storage backup combined startup and standby transformer for thermal power generation according to the present invention, wherein: the distributed photovoltaic energy storage system is connected to the low-voltage side of the thermal power startup and standby transformer as a backup power source for the startup and standby transformer. When the auxiliary power of the power plant requires the startup and standby transformer to supply power, the distributed photovoltaic energy storage system supplies power simultaneously.

[0008] As a preferred solution of the method for configuring a photovoltaic energy storage backup combined startup and standby transformer in thermal power generation according to the present invention, wherein: the modulation wave in the x-th thyristor modulation wave calculation link of the fundamental wave injection method control strategy is:

[0009] m x = M x sin(ωt + δ) + k x sin(ωt + δ)

[0010] = (M x + k x ) × sin(ωt + δ) = m a + m b

[0011] Wherein, M x is the original fundamental wave maximum value, ω is the angular frequency, δ is the power angle, k x is the amplitude of the compensated fundamental frequency modulation wave, m a is the modulation wave before compensation, m b is the compensated fundamental frequency modulation wave. After compensation, the modulation wave only contains the fundamental frequency modulation wave. When the modulation wave is a square wave, the maximum amplitude of the fundamental frequency modulation wave is 4 / π.

[0012] As a preferred solution of the method for configuring a photovoltaic energy storage backup combined startup and standby transformer in thermal power generation according to the present invention, wherein: the modulation wave m x consists of two parts: the initial fundamental frequency modulation wave m ax and the compensated fundamental frequency modulation wave m bx . When the photovoltaic inverter operates in a stable state, the x-th thyristor modulation wave m x is expressed as:

[0013]

[0014] Since the same current flows through each thyristor of the photovoltaic inverter, the AC side voltage u Hx of each thyristor is proportional to the output power P T of the inverter, that is:

[0015]

[0016] Combining the above formulas, the initial fundamental frequency modulation wave m ax of each unit is:

[0017]

[0018] Wherein, u Hx is the AC side voltage of each thyristor, u PVx is the DC side voltage of each thyristor, P xOutput power of the x-th thyristor.

[0019] As a preferred embodiment of the method for configuring a photovoltaic energy storage backup combined startup and standby transformer in thermal power plants according to the present invention, wherein: the adjustment of the thyristor modulation voltage of the photovoltaic inverter includes setting the amplitude of the modulation wave of the overmodulation unit to 1 after compensation, and calculating the fundamental frequency modulation wave m compensated by the x-th photovoltaic inverter thyristor bx , expressed as:

[0020] m bx =(1 - M x )×sin(ωt + δ)

[0021] The total fundamental frequency modulation wave m after adopting the fundamental wave compensation method T is:

[0022]

[0023] The thyristor modulation voltage v of the photovoltaic inverter after adopting the fundamental wave compensation method T is:

[0024]

[0025] In a second aspect, another object of the present invention is to provide a system for configuring a photovoltaic energy storage backup combined startup and standby transformer in thermal power plants, including: a standby unit for thermal power plants and a plant photovoltaic energy storage unit; the standby unit for thermal power plants is used as the backup power supply for the startup and standby transformer. When the plant electricity needs to be supplied by the startup and standby transformer, the distributed photovoltaic energy storage system supplies power simultaneously; the plant photovoltaic energy storage unit is used to introduce an appropriate amount of fundamental wave into the modulation wave calculation link to achieve stable operation of the plant photovoltaic inverter under power imbalance conditions.

[0026] As a preferred embodiment of the system for configuring a photovoltaic energy storage backup combined startup and standby transformer in thermal power plants according to the present invention, wherein: the standby unit for thermal power plants includes a generator, a main transformer, a high-voltage plant transformer, and a startup and standby transformer;

[0027] The generator is connected to the 330 kV power grid system through the main transformer to achieve the output and grid connection of electric energy; the high-voltage plant transformer is used to step down the 20 kV voltage at the generator outlet to 6 kV and connect it to the 6 kV plant bus; the startup and standby transformer is used to step down the voltage of the 330 kV power grid system to 6 kV as the backup power supply for the plant electricity, and its low-voltage side is connected to the 6 kV plant bus.

[0028] As a preferred solution of the thermal power configuration photovoltaic storage backup joint start-up and standby transformation system described in the present invention, wherein: the plant photovoltaic energy storage unit includes a 6kV plant bus, a photovoltaic transformer, a photovoltaic convergence 690V bus, a No. 1 photovoltaic inverter, a No. 1 photovoltaic panel, a No. n photovoltaic inverter, a No. n photovoltaic panel, a No. 1 energy storage box transformer, a No. 1 energy storage system AC cabinet, a No. 1 energy storage module, a No. n energy storage box transformer, a No. n energy storage system AC cabinet, and a No. n energy storage module;

[0029] The 6kV plant bus is used to connect the high-voltage plant transformer output, the low-voltage side of the standby transformer and the input point of the distributed photovoltaic energy storage system to realize the distribution and transmission of electric energy; the photovoltaic panel converts direct current into alternating current through the inverter, converges to the photovoltaic convergence 690V bus, and then boosts the voltage to 6kV through the photovoltaic transformer and then connects to the 6kV plant bus; the energy storage module converts the stored electric energy into 6kV alternating current through the converter cabinet and the energy storage box transformer, and merges it into the 6kV plant bus.

[0030] In a third aspect, a computer device includes a memory and a processor, wherein the memory stores a computer program, and when the processor executes the computer program, the steps of the method for jointly starting and changing the thermal power with photovoltaic storage and backup are implemented as described above.

[0031] In a fourth aspect, a computer-readable storage medium stores a computer program thereon, which, when executed by a processor, implements the steps of the method for jointly starting and changing the thermal power with photovoltaic storage and backup as described above.

[0032] Beneficial effects of the invention: A method and system for configuring a thermal power plant with photovoltaic storage and backup combined with a standby transformer of the invention configures a distributed photovoltaic energy storage system in the 6kV plant section of the thermal power plant, and at the same time, the distributed photovoltaic energy storage system is connected to the low-voltage side of the thermal power standby transformer, which can play the role of a standby transformer backup power supply. When the plant power needs to be supplied by the standby transformer, the distributed photovoltaic energy storage system supplies power at the same time, which can improve the power supply reliability on the basis of reducing the power consumption of the standby transformer. Furthermore, in order to solve the problem of excessive output current distortion rate of the plant photovoltaic inverter under unbalanced input power, the fundamental wave injection control strategy is adopted to introduce an appropriate amount of fundamental wave into the modulation wave calculation link, so as to realize the stable operation of the plant photovoltaic inverter under unbalanced power conditions. BRIEF DESCRIPTION OF THE DRAWINGS

[0033] In order to more clearly illustrate the technical solutions of the embodiments of the present invention, the accompanying drawings required for use in the description of the embodiments will be briefly introduced below. Obviously, the accompanying drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other accompanying drawings can be obtained based on these accompanying drawings without paying creative work.

[0034] Figure 1An overall flow chart of a method for combining thermal power generation with photovoltaic storage and backup power generation provided by an embodiment of the present invention;

[0035] Figure 2 A schematic structural diagram of a thermal power generation system with photovoltaic storage and backup provided in accordance with an embodiment of the present invention. DETAILED DESCRIPTION

[0036] In order to make the above-mentioned purposes, features and advantages of the present invention more obvious and easy to understand, the specific implementation methods of the present invention are described in detail below in conjunction with the drawings of the specification. Obviously, the described embodiments are part of the embodiments of the present invention, but not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary persons in the art without creative work should fall within the scope of protection of the present invention.

[0037] In the following description, many specific details are set forth to facilitate a full understanding of the present invention, but the present invention may also be implemented in other ways different from those described herein, and those skilled in the art may make similar generalizations without violating the connotation of the present invention. Therefore, the present invention is not limited to the specific embodiments disclosed below.

[0038] Example 1

[0039] Reference Figure 1 , which is an embodiment of the present invention, provides a method for starting and distributing a thermal power plant with a photovoltaic power storage backup, comprising:

[0040] S1: Arrange a distributed photovoltaic energy storage system in the power system of a thermal power plant;

[0041] Furthermore, the generator in the thermal power plant standby unit 1 is connected to the 330kV power grid system through the main transformer, and a high-voltage plant transformer is arranged at the generator outlet to reduce the voltage from 20kV to 6kV and connect it to the 6kV plant bus. The 330kV power grid system is connected to the high-voltage side of the standby transformer, which reduces the 330kV voltage to 6kV, and the low-voltage side of the standby transformer is connected to the 6kV plant bus. The photovoltaic panels in the plant photovoltaic energy storage unit are connected to the photovoltaic 690V bus through the inverter, and then boosted to 6kV through the photovoltaic transformer to connect to the 6kV plant bus. The distributed energy storage module is converted to 6kV AC through the converter and booster, and then connected to the 6kV plant bus.

[0042] It should be noted that the deployment of distributed photovoltaic energy storage systems in the power consumption system of thermal power plants can reduce the power consumption rate of the plant and improve the reliability of the power supply for the plant. At the same time, the distributed photovoltaic energy storage system is connected to the low-voltage side of the thermal power start-up transformer, which can serve as a backup power source for the start-up transformer. When the plant power needs to be supplied by the start-up transformer, the distributed photovoltaic energy storage system can supply power at the same time. On the basis of reducing the energy consumption of the start-up transformer, the power supply reliability can be improved.

[0043] S2: Adopt the fundamental wave injection method control strategy and introduce an appropriate amount of fundamental wave into the modulation wave calculation link;

[0044] Furthermore, on the basis of harmonic compensation, a fundamental wave compensation method is proposed, introducing an appropriate amount of fundamental wave into the modulation wave calculation link to achieve the stable operation of the plant-use photovoltaic inverter under power imbalance conditions. The modulation wave of the thyristor modulation wave calculation link of the x-th (x = 1, 2,..., n) photovoltaic inverter is:

[0045] m x = M x sin(ωt + δ) + k x sin(ωt + δ)

[0046] =(M x + k x )×sin(ωt + δ) = m a + m b (1)

[0047] Where: M x is the original fundamental wave maximum value; ω is the angular frequency; δ is the power angle; k x is the amplitude of the compensated fundamental frequency modulation wave; m a is the modulation wave before compensation, and m b is the compensated fundamental frequency modulation wave. The compensated modulation wave only contains the fundamental frequency modulation wave, and when the modulation wave is a square wave, the maximum amplitude of the fundamental frequency modulation wave is 4 / π.

[0048] It can be seen from formula (1) that the modulation wave m x is composed of the initial fundamental frequency modulation wave m ax and the compensated fundamental frequency modulation wave m bx . When the photovoltaic inverter operates in a stable state, the modulation wave m x of the x-th thyristor (x = 1, 2,..., n) can be expressed as:

[0049]

[0050] In the formula: u Hx is the AC side voltage of each thyristor; u PVx is the DC side voltage of each thyristor.

[0051] Since the same current flows through each thyristor of the photovoltaic inverter, the AC side voltage u Hx of each thyristor is proportional to the output power P T of the inverter, that is:

[0052]

[0053] Combining Equation (2) and Equation (3) gives the initial fundamental frequency modulation wave m of each unit ax is

[0054]

[0055] where: P x The output power of the x-th thyristor

[0056] S3: Adjust the thyristor modulation voltage of the photovoltaic inverter using the fundamental wave compensation method

[0057] Furthermore, assume that among n photovoltaic inverter thyristors, i photovoltaic inverter thyristors do not undergo overmodulation, and the remaining photovoltaic inverter thyristors undergo overmodulation, i.e., (0 ≤ M1 to M i ≤ 1, 1 ≤ M i+1 to M n ≤ 1.27).

[0058] To minimize the compensated fundamental frequency modulation wave, the amplitude of the modulation wave of the overmodulation unit is 1 after compensation. The fundamental frequency modulation wave m compensated by the x-th photovoltaic inverter thyristor bx is:

[0059] m bx = (1 - M x ) × sin(ωt + δ) (5)

[0060] Then the total fundamental frequency modulation wave m after using the fundamental wave compensation method T is:

[0061]

[0062] The thyristor modulation voltage v of the photovoltaic inverter after using the fundamental wave compensation method T is:

[0063]

[0064] Embodiment 2

[0065] This is an embodiment of the present invention, providing a thermal power configuration photovoltaic energy storage backup combined startup and standby transformer system, including: a thermal power plant standby unit 1 and a plant photovoltaic energy storage unit 2

[0066] The thermal power plant standby unit 1 is used as the backup power supply for the startup and standby transformer. When the plant power needs to be supplied by the startup and standby transformer, the distributed photovoltaic energy storage system supplies power simultaneously

[0067] The plant photovoltaic energy storage unit 2 is used to introduce an appropriate amount of fundamental wave into the modulation wave calculation link to achieve stable operation of the plant photovoltaic inverter under power imbalance conditions

[0068] The thermal power plant standby unit 1 includes a generator 1-1, a main transformer 1-2, a high-voltage transformer 1-3, and a standby transformer 1-5;

[0069] The generator 1-1 is connected to the 330kV power grid system through the main transformer 1-2 to realize the output and grid connection of electric energy; the high-voltage transformer 1-3 is used to reduce the 20kV voltage at the outlet of the generator 1-1 to 6kV and connect it to the 6kV plant bus 2-1; the standby transformer 1-5 is used to reduce the voltage of the 330kV power grid system to 6kV as a backup power source for plant electricity, and its low-voltage side is connected to the 6kV plant bus 2-1.

[0070] The plant photovoltaic energy storage unit 2 includes a 6kV plant bus 2-1, a photovoltaic transformer 2-3, a photovoltaic bus 690V bus 2-4, a No. 1 photovoltaic inverter 2-6, a No. 1 photovoltaic panel 2-7, a No. n photovoltaic inverter 2-9, a No. n photovoltaic panel 2-10, a No. 1 energy storage box transformer 2-12, a No. 1 energy storage system AC cabinet 2-13, a No. 1 energy storage module 2-14, a No. n energy storage box transformer 2-16, a No. n energy storage system AC cabinet 2-17, and a No. n energy storage module 2-18;

[0071] The 6kV plant bus 2-1 is used to connect the high-voltage plant transformer output, the low-voltage side of the standby transformer and the input point of the distributed photovoltaic energy storage system to achieve the distribution and transmission of electric energy; the photovoltaic panel converts direct current into alternating current through the inverter, converges to the photovoltaic convergence 690V bus 2-4, and then boosts the voltage to 6kV through the photovoltaic transformer 2-3 and then connects to the 6kV plant bus 2-1; the energy storage module converts the stored electric energy into 6kV alternating current through the converter cabinet and the energy storage box transformer, and merges it into the 6kV plant bus 2-1.

[0072] 1-4 switch S1: located between the high-voltage transformer and the 6kV plant bus, controls whether the stepped-down electric energy enters the 6kV plant bus.

[0073] 1-6 switch S2: Located between the standby transformer and the 6kV factory bus, it serves as the control switch for the standby power supply. When the main power supply fails, the power of the standby transformer can be introduced into the 6kV factory bus by closing the switch.

[0074] 2-2 Switch S3: Located between the 690V PV busbar and the PV transformer, it controls whether the PV energy storage unit supplies power to the 6kV factory busbar.

[0075] 2-11 switch S4, 2-15 switch S5: located between the distributed energy storage module and the 6kV plant bus, controlling whether the distributed energy storage module supplies power to the 6kV plant bus.

[0076] Switch S1: Usually related to the operating status of the generator, the load demand of the high-voltage transformer and the grid dispatching instructions. The switch is opened and closed according to actual needs through the automatic control system of the thermal power plant or manual operation.

[0077] Switch S2: As the control switch of the standby power supply, its opening and closing are usually related to the fault status of the main power supply, the voltage condition of the 6kV auxiliary bus, and the power grid dispatching instructions. When the main power supply fails or the voltage is abnormal, the automatic control system will detect these signals and automatically close the standby transformer to introduce the standby power supply into the 6kV auxiliary bus. At the same time, it can also be controlled manually.

[0078] Switches S3, S4, S5: They are related to the power generation of the photovoltaic energy storage unit, the load demand of the 6kV auxiliary bus, and the power grid dispatching instructions. Through the automatic control system or manual operation of the photovoltaic energy storage system, the opening and closing of the switches are controlled according to actual needs to achieve grid-connected power generation and power distribution of the photovoltaic energy storage unit.

[0079] When the generator shuts down due to a fault, the automatic control system may immediately disconnect S1 and attempt to close S2 to start the standby transformer SBT as the standby power supply to ensure continuous power supply to the auxiliary power system.

[0080] When the light intensity suddenly decreases, resulting in insufficient power generation of the photovoltaic energy storage system, the automatic control system may adjust the opening and closing state of S3 to obtain more electric energy from the power grid or other power supply sources to meet the auxiliary power demand.

[0081] When a short-circuit fault occurs in the auxiliary power system, the relevant protection devices may quickly disconnect switches such as S2 and S4 to prevent the expansion of the fault and protect the equipment safety. At the same time, the automatic control system may start the standby power supply or take other emergency measures to ensure the stable operation of the auxiliary power system.

[0082] It is implemented through the automatic control system of the power plant (such as DCS, SCADA, etc.) to ensure reliable and stable power supply to the auxiliary power system under various working conditions.

[0083] Embodiment 3

[0084] An embodiment of the present invention, which is different from the previous two embodiments in that:

[0085] If the above-mentioned functions are implemented in the form of software functional units and sold or used as independent products, they can be stored in a computer-readable storage medium. Based on this 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 aforementioned storage medium includes: various media that can store program codes, such as USB flash drives, mobile hard disks, read-only memories (ROM, Read-Only Memory), random access memories (RAM, Random Access Memory), magnetic disks, or optical discs.

[0086] 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 instructions from the instruction execution system, apparatus, or device and execute the instructions), 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 transmit a program for use by or in combination with an instruction execution system, apparatus, or device.

[0087] More specific examples (non-exhaustive list) of computer-readable media include the following: electrical connection parts with one or more wirings (electronic devices), portable computer disk cartridges (magnetic devices), random access memories (RAM), read-only memories (ROM), erasable programmable read-only memories (EPROM or flash memories), fiber optic devices, and portable compact disc read-only memories (CDROM). Additionally, the computer-readable medium can even be paper or other suitable media on which the program can be printed, because the program can be obtained electronically, for example, by optically scanning the paper or other media, then editing, interpreting, or otherwise processing it as appropriate, and then storing it in a computer memory.

[0088] 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 by 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 with logic gate circuits for implementing logical functions on data signals, application specific integrated circuits with suitable combinational logic gate circuits, programmable gate arrays (PGAs), field programmable gate arrays (FPGAs), etc.

[0089] 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 starting and changing a thermal power plant with a photovoltaic power plant and a backup power plant, characterized in that: include: Arrange a distributed photovoltaic energy storage system in the power system of a thermal power plant; Adopt the fundamental wave injection control strategy to introduce an appropriate amount of fundamental wave into the modulation wave calculation link; The fundamental wave compensation method is used to adjust the thyristor modulation voltage of the photovoltaic inverter.

2. The method for combined startup and standby transformation of thermal power configuration with photovoltaic power storage and backup as claimed in claim 1, characterized in that: The distributed photovoltaic energy storage system is connected to the low-voltage side of the thermal power standby transformer as a backup power source for the standby transformer. When the factory electricity needs to be supplied by the standby transformer, the distributed photovoltaic energy storage system supplies power at the same time.

3. The method for combined startup and standby transformation of thermal power configuration with photovoltaic power storage and backup as claimed in claim 1, characterized in that: The modulation wave of the xth photovoltaic inverter thyristor modulation wave calculation link in the fundamental wave injection control strategy is: m x =M x sin(ωt+δ)+k x sin(ωt+δ) =(M x +k x )×sin(ωt+δ)=m a +m b Among them, M x is the maximum value of the original fundamental wave, ω is the angular frequency, δ is the power angle, k x To compensate for the amplitude of the fundamental frequency modulation wave, m a To compensate for the pre-modulation wave, m b The compensated fundamental frequency modulation wave is a compensated fundamental frequency modulation wave. The compensated modulation wave only contains the fundamental frequency modulation wave. When the modulation wave is a square wave, the maximum amplitude of the fundamental frequency modulation wave is 4 / π.

4. The method for combined startup and standby transformation of thermal power configuration with photovoltaic power storage and backup as claimed in claim 3, characterized in that: The modulation wave m x The initial base frequency modulation wave m ax and compensation base frequency modulation wave m bx It consists of two parts. When the photovoltaic inverter is running in a stable state, the xth thyristor modulation wave m x It is expressed as: Since the same current flows through each thyristor of the photovoltaic inverter, the AC side voltage u Hx and inverter output power P T is proportional, that is: Combining the above formulas, we can get the initial baseband modulation wave m of each unit. ax for: Among them, u Hx is the AC side voltage of each thyristor, u PVx is the DC side voltage of each thyristor, P x The output power of the xth thyristor.

5. The method for combined startup and standby transformation of thermal power configuration with photovoltaic power storage and backup as claimed in claim 4, characterized in that: The adjustment of the photovoltaic inverter thyristor modulation voltage includes setting the amplitude of the modulation wave of the overmodulation unit to 1 after compensation, calculating the base frequency modulation wave m of the xth photovoltaic inverter thyristor compensation bx , expressed as: m bx =(1-M x )×sin(ωt+δ) The total amount of fundamental frequency modulation wave m after using the fundamental wave compensation method T for: The thyristor modulation voltage v of the photovoltaic inverter after adopting the fundamental wave compensation method T for:

6. A system using the method for combined startup and standby transformation of thermal power configuration with photovoltaic storage and backup as claimed in any one of claims 1 to 5, characterized in that: include: A thermal power plant standby unit (1) and a plant photovoltaic energy storage unit (2); The thermal power plant standby unit (1) is used to start the standby transformer backup power supply. When the plant power needs to be powered by the standby transformer, the distributed photovoltaic energy storage system supplies power at the same time. The plant photovoltaic energy storage unit (2) is used to introduce an appropriate amount of fundamental wave into the modulation wave calculation link, so as to achieve stable operation of the plant photovoltaic inverter under power imbalance conditions.

7. The thermal power configuration photovoltaic storage backup combined start-up and standby transformation system according to claim 6, characterized in that: The thermal power plant standby unit (1) comprises a generator (1-1), a main transformer (1-2), a high-voltage transformer (1-3), and a standby transformer (1-5); The generator (1-1) is connected to a 330kV power grid system via a main transformer (1-2) to achieve the output and grid connection of electric energy; the high-voltage plant transformer (1-3) is used to reduce the 20kV voltage at the generator (1-1) outlet to 6kV and connect it to a 6kV plant bus (2-1); the standby transformer (1-5) is used to reduce the voltage of the 330kV power grid system to 6kV as a backup power source for plant electricity, and its low-voltage side is connected to the 6kV plant bus (2-1).

8. The thermal power configuration photovoltaic storage backup combined start-up and standby transformation system according to claim 7, characterized in that: The plant photovoltaic energy storage unit (2) comprises a 6 kV plant busbar (2-1), a photovoltaic transformer (2-3), a photovoltaic busbar (2-4), a No. 1 photovoltaic inverter (2-6), a No. 1 photovoltaic panel (2-7), a No. n photovoltaic inverter (2-9), a No. n photovoltaic panel (2-10), a No. 1 energy storage box transformer (2-12), a No. 1 energy storage system AC cabinet (2-13), a No. 1 energy storage module (2-14), a No. n energy storage box transformer (2-16), a No. n energy storage system AC cabinet (2-17), and a No. n energy storage module (2-18); The 6kV plant bus (2-1) is used to connect the high-voltage plant transformer output, the low-voltage side of the standby transformer and the input point of the distributed photovoltaic energy storage system to achieve the distribution and transmission of electric energy; the photovoltaic panel converts direct current into alternating current through an inverter, which is then converged to the photovoltaic convergence 690V bus (2-4), and then boosted to 6kV through the photovoltaic transformer (2-3) and connected to the 6kV plant bus (2-1); the energy storage module converts the stored electric energy into 6kV alternating current through a converter cabinet and an energy storage box transformer, and is then merged into the 6kV plant bus (2-1).

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 jointly starting and changing thermal power with photovoltaic storage and backup according to any one of claims 1 to 5 are implemented.

10. A computer-readable storage medium having a computer program stored thereon, characterized in that: When the computer program is executed by a processor, the steps of the method for jointly starting and changing thermal power with photovoltaic storage and backup according to any one of claims 1 to 5 are implemented.

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