Thermal power energy storage distributed high-voltage DC confluence segmented frequency modulation system and method

Abstract

The invention discloses a thermal power storage distributed high-voltage DC confluence segmented frequency modulation system and method, and relates to the field of thermal power storage, and the method comprises the steps: electric energy generated by generators enters a thermal power storage segmented commutation access unit through outlets of a first generator and a second generator; electric energy enters the energy storage grid-connected current converter through the energy storage alternating-current bus and enters the energy storage direct-current boosting confluence unit by adopting a virtual impedance alternating-current droop control scheme, so that power regulation and control are completed. According to the invention, a sectional power regulation strategy is adopted, the output fluctuation of the thermal power generating unit and the load demand change are accurately matched, and the bus voltage oscillation caused by power abrupt change is reduced; through dynamic distribution of the charging and discharging power of the energy storage unit and time sequence coordination of the current conversion module, the energy storage utilization rate is optimized, the service life of equipment is prolonged, the single-point fault risk of traditional centralized current conversion is avoided, and the redundancy reliability of the system is enhanced; the modular segmentation design can flexibly expand the commutation capacity and reduce the system upgrading cost.

Description

Technical Field

[0001] The present invention relates to the field of thermal power energy storage, and in particular to a thermal power energy storage distributed high-voltage direct current convergence segmented frequency modulation system and method. Background Art

[0002] At present, the typical design of the power supply system of large thermal power units is to tap the step-down transformer at the generator outlet, which can be divided into two-stage transformers. The first stage is to step down the 20kV at the generator outlet to 6kV, and the second stage is to step down the 6kV to 400V. Both use industrial frequency transformers and involve AC power. With the continuous increase in the capacity of the unit, the capacity of the power supply system is also increasing. The capacity of the high-voltage power supply transformer is getting larger, and the short-circuit current of the power supply system is very large, which puts higher requirements on the short-circuit breaking capacity of the high-voltage switch. In order to meet the requirements of short-circuit thermal stability, the high-voltage cable of the power supply system needs to choose thicker cables, which increases the investment cost. Traditional high-voltage power supply transformers use industrial frequency transformers, which are huge in size, and in order to obtain a larger capacity of the power supply system, they are often remodeled for capacity expansion. The cost of the transformation is huge, the construction period is long, and the normal power generation of the power plant is delayed.

[0003] The use of DC networking in the power supply system can effectively solve some bottleneck problems in the development of traditional AC power supply systems. Compared with the traditional AC power supply system, DC networking has many advantages: DC networking has a larger power supply capacity; DC networking does not need to consider phase angle and frequency, and can realize asynchronous system interconnection. The power supply load is connected to the DC power supply system through the rectifier, which can improve the efficiency of power conversion and reduce equipment loss, realize load variable frequency 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-mentioned problems, the present invention is proposed.

[0005] Therefore, the technical problem solved by the present invention is: how to achieve dynamic power coordination, frequency regulation accuracy improvement and system redundancy fault tolerance between thermal power units and distributed energy storage through a segmented high-voltage commutation architecture and an adaptive droop control strategy, while suppressing high-voltage DC bus voltage fluctuations.

[0006] In order to solve the above technical problems, the present invention provides the following technical solutions: a thermal power energy storage distributed high-voltage direct current convergence segmented frequency modulation system, which comprises the following steps: A thermal power energy storage segmented commutation access unit, comprising a first generator and a second generator arranged in the thermal power energy storage segmented commutation access unit, wherein the first generator and the second generator are respectively stepped up to 330 kV through a first main transformer and a second main transformer and connected to a 330 kV power grid, and the outlets of the first generator and the second generator are connected to AC 20 kV energy storage A and B segment busbars, and are respectively connected to the A segment energy storage grid-connected converter and the B segment energy storage grid-connected converter through the A segment energy storage AC grid-connected switch and the B segment energy storage AC grid-connected switch; An energy storage DC boost busbar unit, comprising a 28.28 kV DC energy storage busbar disposed on the energy storage DC boost busbar unit, connected to a first energy storage access switch and a second energy storage access switch respectively; The first energy storage access switch sequentially connects the first power electronic transformer high-voltage converter, the high-frequency transformer, the first power electronic transformer low-voltage converter and the first energy storage module; The second energy storage access switch sequentially connects the second power electronic transformer high-voltage converter, the high-frequency transformer, the second power electronic transformer low-voltage converter and the second energy storage module.

[0007] As a preferred solution of a thermal power energy storage distributed high-voltage DC bus segmented frequency modulation system described in the present invention, the energy storage DC boost bus unit includes connecting the DC 28.28kV energy storage bus through the A section energy storage DC grid-connected circuit breaker and the B section energy storage DC grid-connected circuit breaker to the A section energy storage grid-connected converter and the B section energy storage grid-connected converter in the unit respectively, so that the energy storage electric energy interacts with the generator through the segmented high-voltage converter device.

[0008] As a preferred solution of the thermal power energy storage distributed high-voltage direct current convergence segmented frequency regulation system described in the present invention, wherein: the segmented frequency regulation system adopts a segmented commutation solution, using two sets of segmented high-voltage commutation devices, and the two sets of devices are connected through a structure to perform power regulation control; One section of energy storage assists the frequency regulation of the first generator or the second generator alone, or assists the frequency regulation of the first and second generators at the same time, to complete the frequency regulation of the auxiliary thermal power unit; The two sets of segmented high-voltage converter devices are a first power electronic transformer high-voltage converter and a second power electronic transformer high-voltage converter.

[0009] As a preferred solution of the thermal power energy storage distributed high-voltage direct current convergence segmented frequency regulation system described in the present invention, wherein: the segmented high-voltage converter adopts a virtual impedance AC droop control scheme in the segmented high-voltage converter, by establishing voltage-active power and frequency-reactive power droop control equations, and using adaptive virtual impedance to compensate for the voltage-active power droop coefficient, so that the two sets of segmented high-voltage converters assist the thermal power unit in achieving the optimal frequency regulation performance; Adopting an adaptive DC droop control scheme in each energy storage grid-connected converter, the adaptive DC active power-voltage droop coefficient is used to adjust the DC voltage regulation range, active power regulation amount and voltage regulation rate; The energy storage grid-connected converter includes a section A energy storage grid-connected converter, a section B energy storage grid-connected converter, a first power electronic transformer high-voltage converter, a first power electronic transformer low-voltage converter, a second power electronic transformer high-voltage converter, and a second power electronic transformer low-voltage converter.

[0010] Another object of the present invention is to provide a method for segmented frequency modulation of distributed high-voltage direct current convergence in thermal power energy storage.

[0011] In order to solve the above technical problems, the present invention provides the following technical solutions: a thermal power energy storage distributed high voltage direct current convergence segmented frequency modulation method, comprising: the electric energy generated by the generator enters the thermal power energy storage segmented commutation access unit through the outlets of the first generator and the second generator; Electric energy enters the energy storage grid-connected converter through the energy storage AC bus, and enters the energy storage DC boost bus unit using a virtual impedance AC droop control scheme to complete power regulation control.

[0012] As a preferred solution of the thermal power energy storage distributed high-voltage direct current convergence segmented frequency modulation method described in the present invention, the virtual impedance AC droop control solution is to establish voltage-active power and frequency-reactive power droop control equations, and the expression is: , in, is the output voltage amplitude of the i-th set of segmented high-voltage converter devices; The output voltage reference value of the i-th set of segmented high-voltage converter devices; is the voltage-active power droop coefficient of the i-th set of segmented high-voltage converter devices; Output / absorb active power for i sets of segmented high-voltage converter devices; Output frequency current value of the i-th set of segmented high-voltage converter devices; Outputting a frequency reference value for the i-th set of segmented high-voltage converter devices; is the frequency-reactive power droop coefficient of the i-th segmented high-voltage converter device; Output / absorb reactive power for the i-th set of segmented high-voltage converter devices.

[0013] As a preferred solution of the thermal power energy storage distributed high-voltage direct current convergence segmented frequency modulation method described in the present invention, the virtual impedance AC droop control solution includes using adaptive virtual impedance to compensate for the voltage-active power droop coefficient to improve the active power distribution accuracy, and the expression is: , in, The actual power rating output / absorption of the i-th set of segmented high-voltage converter devices; , The output / absorption actual power rating of the first and second sets of segmented high-voltage converters; is the grid connection point voltage of the i-th set of segmented high-voltage converter devices, i.e., the outlet voltage of #1 and #2 generators; , is the adaptive virtual impedance, is the energy storage output voltage reference value; , in, It is the active power PI adjustment proportional coefficient.

[0014] As a preferred solution of the thermal power energy storage distributed high-voltage direct current bus segmented frequency modulation method described in the present invention, the virtual impedance AC droop control solution also includes stabilizing the control of the energy storage bus voltage of the energy storage direct current boost bus unit, and adopting an adaptive direct current active power-voltage droop coefficient in the traditional direct current active power voltage droop control method, and the expression is: , , in, is the DC side output voltage of the jth set of energy storage grid-connected converter; is the DC energy storage bus voltage reference value; is the DC active power-voltage droop coefficient in the control system of the j-th energy storage grid-connected converter; is the current value of active power output / absorbed by the jth set of energy storage grid-connected converter; is the target value of active power output / absorption of the jth set of energy storage grid-connected converter, is the fixed voltage droop control coefficient, is the maximum DC voltage adjustment range of the j-th energy storage grid-connected converter; is the maximum active power regulation value of the j-th energy storage grid-connected converter; is the DC voltage regulation rate of the j-th set of energy storage grid-connected converter. When the deviation is larger, the adaptive DC active power-voltage droop coefficient becomes smaller. When facing the same active power regulation amount, the voltage variation range is reduced.

[0015] 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 above-mentioned method for segmented frequency modulation of distributed high-voltage direct current convergence of thermal power energy storage are implemented.

[0016] A computer-readable storage medium stores a computer program, which, when executed by a processor, implements the steps of a thermal power energy storage distributed high-voltage direct current convergence segmented frequency modulation method as described above.

[0017] Beneficial effects of the present invention: The present invention adopts a segmented power regulation strategy to accurately match the output fluctuations of thermal power units with changes in load demand, reducing bus voltage oscillations caused by power mutations; by dynamically allocating the charging and discharging power of the energy storage unit and coordinating the timing of the commutation module, it optimizes the energy storage utilization rate, extends the equipment life, avoids the single-point failure risk of traditional centralized commutation, and enhances the redundancy reliability of the system; the modular segmented design can flexibly expand the commutation capacity and reduce the system upgrade cost. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] 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.

[0019] Figure 1 A structural diagram of a thermal power energy storage distributed high-voltage direct current convergence segmented frequency modulation system provided for the first embodiment of the present invention.

[0020] Among them: 1. Thermal power energy storage segmented conversion access unit, 11. First generator, 12. No. 1 main transformer, 13. 330kV power grid system, 14. Section A energy storage AC grid-connected switch, 15. Section A energy storage grid-connected converter, 16. Section A energy storage DC grid-connected circuit breaker, 17. Section B energy storage AC grid-connected switch, 18. Section B energy storage grid-connected converter, 19. Section B energy storage DC grid-connected circuit breaker, 110. Second generator, 111. No. 2 main transformer, 2. Energy storage DC boost busbar, 21, 28.28kV DC energy storage busbar, 22, first energy storage access switch, 23, first power electronic transformer high voltage converter, 24, high frequency transformer, 25, first power electronic transformer low voltage converter, 26, first energy storage module, 27, second energy storage access switch, 28, second power electronic transformer high voltage converter, 29, second power electronic transformer low voltage converter, 210, second energy storage module. DETAILED DESCRIPTION

[0021] 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.

[0022] Example 1, reference Figure 1 As one embodiment of the present invention, a thermal power energy storage distributed high voltage direct current convergence segmented frequency modulation system is provided, comprising: The present invention constructs each energy storage module to step up the voltage through a DC transformer, converge to a DC 28.28kV energy storage bus, and respectively connect to the #1 and #2 generator outlets through a segmented high-voltage converter to assist the generator in frequency regulation, thereby achieving the purpose of assisting the frequency regulation of two thermal power units with a segmented energy storage. Furthermore, in order to achieve the voltage stability of the DC 28.28kV energy storage bus, an adaptive DC droop control scheme is adopted in the high-voltage side converter of each energy storage DC transformer to ensure the stability of the DC bus voltage. A virtual impedance AC droop control scheme is adopted in the energy storage grid-connected converter to improve the power distribution accuracy during the frequency regulation process, and ensure that the two sets of segmented high-voltage converters assist the thermal power units in frequency regulation with the best performance.

[0023] Construction of thermal power energy storage segmented commutation access unit: The first step is to connect the generator to the 330kV power grid system through the main transformer to build the basic framework for subsequent power transmission and interaction.

[0024] The thermal power energy storage segmented commutation access unit comprises a first generator and a second generator arranged in the thermal power energy storage segmented commutation access unit 1, wherein the first generator and the second generator are respectively stepped up to 330 kV through a first main transformer and a second main transformer and connected to a 330 kV power grid, and the outlets of the first generator and the second generator are connected to AC 20 kV energy storage A and B segment busbars, and are respectively connected to the A segment energy storage grid-connected converter and the B segment energy storage grid-connected converter 18 through the A segment energy storage AC grid-connected switch and the B segment energy storage AC grid-connected switch; An energy storage DC boost busbar unit, comprising a 28.28 kV DC energy storage busbar disposed on the energy storage DC boost busbar unit, connected to a first energy storage access switch and a second energy storage access switch respectively; The first energy storage access switch sequentially connects the first power electronic transformer high-voltage converter, the high-frequency transformer, the first power electronic transformer low-voltage converter and the first energy storage module; The second energy storage access switch sequentially connects the second power electronic transformer high-voltage converter, the high-frequency transformer, the second power electronic transformer low-voltage converter and the second energy storage module.

[0025] In the second step, based on the connection between the generator and the grid completed in the first step, two sets of segmented high-voltage commutation devices are set in the thermal power energy storage segmented commutation access unit 1, and their AC sides are connected to the #1 and #2 generator outlets through the A and B segment energy storage grid-connected switches respectively. This step, with the help of the connection results of the first step, realizes the connection between the commutation device and the generator outlet, providing an electrical path for energy storage to assist the generator frequency regulation.

[0026] The DC 28.28kV energy storage bus is connected to the A-section energy storage grid-connected converter and the B-section energy storage grid-connected converter in the thermal power energy storage segmented conversion access unit 1 through the A-section energy storage DC grid-connected circuit breaker and the B-section energy storage DC grid-connected circuit breaker, respectively, so that the energy storage electric energy interacts with the generator through the segmented high-voltage conversion device.

[0027] Energy storage DC boost bus unit construction: Step 3: Based on the construction of the thermal power energy storage segmented commutation access unit completed in the previous step, the energy storage DC boost converging unit 2 is constructed. In this unit, each energy storage module performs DC transformation and DC networking. Since its networking form is simple and efficient, it can quickly process the electric energy of each energy storage module. This step is based on the system foundation of the previous step and completes the preliminary construction of the energy storage part.

[0028] Step 4: Based on the energy storage DC boost busbar 2 constructed in step 3, the DC 28.28kV energy storage busbar is connected to the DC side of the energy storage grid-connected converters of sections A and B through the energy storage DC circuit breakers of sections A and B in the thermal power energy storage segmented commutation access unit 1. This step completes the connection between the two units, allowing the energy storage power to interact with the generator through the segmented high-voltage commutation device, and perfecting the electrical connection of the entire system.

[0029] Achieve energy storage assisted frequency regulation function: Step 5, based on the entire system that has been built, adopt the segmented commutation scheme and use two sets of segmented high-voltage commutation devices. These two sets of devices use the existing connection architecture of the system to control the power regulation, so that one section of energy storage can assist the frequency regulation of the #1 or #2 machine alone, or assist the frequency regulation of the #1 and #2 machines at the same time, so as to achieve the purpose of assisting the frequency regulation of the thermal power unit.

[0030] Step 6: On the basis of using segmented high-voltage converters to achieve frequency regulation in step 5, a virtual impedance AC droop control scheme is used in the energy storage grid-connected converter to improve the power distribution accuracy during the frequency regulation process. By establishing voltage-active power and frequency-reactive power droop control equations and using adaptive virtual impedance to compensate for the voltage-active power droop coefficient, the frequency regulation performance of the two sets of segmented high-voltage converters to assist thermal power units is optimized.

[0031] Maintaining stable energy storage bus voltage: In step 7, to achieve stable DC 28.28kV energy storage bus voltage, an adaptive DC droop control scheme is used in each energy storage grid-connected converter based on the entire system architecture and the completed boost convergence of the energy storage module.

[0032] In step 8, the conventional DC active voltage droop control equation is improved according to the adaptive DC droop control scheme adopted in step 7. By adopting the adaptive DC active-voltage droop coefficient, the DC voltage regulation range, active power regulation amount, voltage regulation rate and other factors are adjusted to effectively reduce the DC bus voltage deviation during the active power regulation process and ensure the stability of the DC bus voltage.

[0033] It is further explained that the virtual impedance AC droop control scheme is adopted in the segmented high-voltage converter. By establishing the voltage-active power and frequency-reactive power droop control equations and using adaptive virtual impedance to compensate the voltage-active power droop coefficient, the frequency regulation performance of the two sets of segmented high-voltage converters to assist the thermal power units is optimized. An adaptive DC droop control scheme is adopted in each energy storage grid-connected converter, and an adaptive DC active power-voltage droop coefficient is adopted to adjust according to the DC voltage regulation range, active power regulation amount and voltage regulation rate.

[0034] The energy storage grid-connected converter includes a section A energy storage grid-connected converter, a section B energy storage grid-connected converter, a first power electronic transformer high-voltage converter, a first power electronic transformer low-voltage converter, a second power electronic transformer high-voltage converter, and a second power electronic transformer low-voltage converter.

[0035] It is further explained that: The thermal power energy storage distributed high-voltage DC bus segmented commutation system includes: a thermal power energy storage segmented commutation access unit 1; an energy storage DC boost bus unit 2. Wherein: the generator in the thermal power energy storage segmented commutation access unit 1 is connected to the 330kV power grid system through the main transformer, and contains two sets of segmented high-voltage commutation devices, and the AC side is connected to the #1 and #2 generator outlets through the A section and B section energy storage grid-connected switches respectively. The DC 28.28kV energy storage bus in the energy storage DC boost bus unit 2 is connected to the DC side of the A section and B section energy storage segmented high-voltage commutation devices through the A section and B section energy storage DC circuit breakers in the thermal power energy storage segmented commutation access unit 1. In the energy storage DC boost bus unit 2, each energy storage module is DC-transformed and DC-networked, and the networking form is simple and efficient.

[0036] A further improvement of the present invention is that, in order to realize one-stage energy storage to assist the frequency regulation of two thermal power units, this paper adopts a segmented commutation scheme and two sets of segmented high-voltage commutation devices. By performing power regulation control on the two sets of segmented high-voltage commutation devices, one-stage energy storage can independently assist the frequency regulation of #1 or #2, or simultaneously assist the frequency regulation of #1 and #2.

[0037] A further improvement of the present invention is that a virtual impedance AC droop control scheme is adopted in the segmented high-voltage commutation device to improve the power distribution accuracy during the frequency regulation process and ensure that the two sets of segmented high-voltage commutation devices assist the thermal power units in achieving optimal frequency regulation performance.

[0038] A further improvement of the present invention is that, in order to achieve a stable DC 28.28kV energy storage bus voltage, an adaptive DC droop control scheme is adopted in each high-voltage side converter of the energy storage DC transformer to ensure a stable DC bus voltage.

[0039] A further improvement of the present invention is that in the energy storage DC boost merging unit 2, each energy storage module is DC-transformed and DC-networked, and the networking form is simple and efficient.

[0040] Embodiment 2 is an embodiment of the present invention, which provides a thermal power energy storage distributed high voltage direct current convergence segmented frequency modulation method, comprising: the electric energy generated by the generator enters the thermal power energy storage segmented commutation access unit through the outlets of the first generator and the second generator; Electric energy enters the energy storage grid-connected converter through the energy storage AC bus, and enters the energy storage DC boost bus unit using a virtual impedance AC droop control scheme to complete power regulation control.

[0041] It is further explained that: The virtual impedance AC droop control scheme is to establish voltage-active power and frequency-reactive power droop control equations, which are expressed as follows: (1) in, is the output voltage amplitude of the i-th set of segmented high-voltage converter devices; The output voltage reference value of the i-th set of segmented high-voltage converter devices; is the voltage-active power droop coefficient of the i-th set of segmented high-voltage converter devices; Output / absorb active power for i sets of segmented high-voltage converter devices; Output frequency current value of the i-th set of segmented high-voltage converter devices; Outputting a frequency reference value for the i-th set of segmented high-voltage converter devices; is the frequency-reactive power droop coefficient of the i-th segmented high-voltage converter device; Output / absorb reactive power for the i-th set of segmented high-voltage converter devices.

[0042] The output voltage on the AC side of the high-voltage converter will have low active power distribution accuracy during the frequency regulation process due to the impedance mismatch of the connected transmission line, namely the 20kV energy storage AC bus line, that is, there is an active power regulation deviation.

[0043] Adaptive virtual impedance is used to compensate the voltage-active power droop coefficient to improve the accuracy of active power distribution. The voltage-active power droop compensation coefficient with adaptive virtual impedance is: (2) in, The actual power rating output / absorption of the i-th set of segmented high-voltage converter devices; , The output / absorption actual power rating of the first and second sets of segmented high-voltage converters; is the grid connection point voltage of the i-th set of segmented high-voltage converter devices, i.e., the outlet voltage of #1 and #2 generators; , It is an adaptive virtual impedance that can compensate for active power deviation, distribute active power according to capacity, and accurately adjust power according to frequency modulation instructions. It is the reference value of energy storage output voltage.

[0044] The adaptive virtual impedance can be expressed as: (3) in, is the active power PI adjustment proportional coefficient. Substituting the voltage-active power droop compensation coefficient containing the adaptive virtual impedance in formula (2) into the voltage-active power droop control equation in formula (1), the droop control equation after active power deviation compensation can be obtained as follows: (4) In order to achieve the stability of the DC 28.28kV energy storage bus voltage, an adaptive DC droop control scheme is adopted in the high-voltage side converter of each energy storage DC transformer to ensure the stability of the DC bus voltage.

[0045] The traditional DC active voltage droop control equation is: (5) in, is the DC side output voltage of the high-voltage side converter of the j-th energy storage DC transformer; It is the DC 28.28kV energy storage bus voltage reference value; is the DC active power-voltage droop coefficient in the high-voltage side converter control system of the j-th energy storage DC transformer; is the current value of active power output / absorbed by the high-voltage side converter of the j-th energy storage DC transformer; is the target value of active power output / absorption of the high-voltage side converter of the jth energy storage DC transformer. In order to maintain the DC 28.28kV energy storage bus voltage more stable and reduce the DC bus voltage deviation during active power regulation, an adaptive DC active-voltage droop coefficient is adopted, which can be expressed as: (6) in, is the fixed voltage droop control coefficient, is the maximum DC voltage regulation range of the high-voltage side converter of the j-th energy storage DC transformer; is the maximum active power regulation value of the high-voltage side converter of the j-th energy storage DC transformer; is the DC voltage regulation rate of the high-voltage side converter of the j-th energy storage DC transformer. When the deviation is larger, the adaptive DC active power-voltage droop coefficient becomes smaller. When facing the same active power regulation amount, the voltage variation range is reduced, which can effectively reduce the DC bus voltage deviation.

[0046] If the 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, or the part that contributes to the prior art or the part of the technical solution, can be embodied in the form of a software product. The computer software product is stored in a storage medium, including several instructions for a computer device (which can be a personal computer, a server, or a network device, etc.) to perform all or part of the steps of the methods described in each embodiment of the present invention. The aforementioned storage medium includes: U disk, mobile hard disk, read-only memory (ROM, Read-Only Memory), random access memory (RAM, Random Access Memory), disk or optical disk, etc., which can store program codes.

[0047] The logic and / or steps represented in the flowchart or otherwise described herein, for example, can be considered as an ordered list of executable instructions for implementing logical functions, and can be embodied in any computer-readable medium for use by an instruction execution system, device or apparatus (such as a computer-based system, a system including a processor, or other system that can fetch instructions from an instruction execution system, device or apparatus and execute instructions), or in conjunction with such instruction execution systems, devices or apparatuses. For the purposes of this specification, "computer-readable medium" can be any device that can contain, store, communicate, propagate or transmit a program for use by an instruction execution system, device or apparatus, or in conjunction with such instruction execution systems, devices or apparatuses.

[0048] More specific examples of computer-readable media (a non-exhaustive list) include the following: an electrical connection with one or more wires (electronic device), a portable computer disk case (magnetic device), a random access memory (RAM), a read-only memory (ROM), an erasable and programmable read-only memory (EPROM or flash memory), an optical fiber device, and a portable compact disk read-only memory (CDROM). In addition, the computer-readable medium may even be a paper or other suitable medium on which the program is printed, since the program may be obtained electronically, for example, by optically scanning the paper or other medium, followed by editing, deciphering or, if necessary, processing in another suitable manner, and then stored in a computer memory.

[0049] It should be understood that the various parts of the present invention can be implemented by hardware, software, firmware or a combination thereof. In the above-mentioned 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, it can be implemented by any one of the following technologies known in the art or their combination: a discrete logic circuit having a logic gate circuit for implementing a logic function for a data signal, a dedicated integrated circuit having a suitable combination of logic gate circuits, a programmable gate array (PGA), a field programmable gate array (FPGA), etc.

[0050] It should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention rather than to limit it. Although the present invention has been described in detail with reference to the preferred embodiments, those skilled in the art should understand that the technical solutions of the present invention may be modified or replaced by equivalents without departing from the spirit and scope of the technical solutions of the present invention, which should all be included in the scope of the claims of the present invention.

Claims

1. A thermal power energy storage distributed high voltage direct current convergence segmented frequency modulation system, characterized in that: include: A thermal power energy storage segmented commutation access unit, comprising a first generator and a second generator arranged in the thermal power energy storage segmented commutation access unit, wherein the first generator and the second generator are respectively stepped up to 330 kV through a first main transformer and a second main transformer and connected to a 330 kV power grid, and the outlets of the first generator and the second generator are connected to AC 20 kV energy storage A and B segment busbars, and are respectively connected to the A segment energy storage grid-connected converter and the B segment energy storage grid-connected converter through the A segment energy storage AC grid-connected switch and the B segment energy storage AC grid-connected switch; An energy storage DC boost busbar unit, comprising a 28.28 kV DC energy storage busbar disposed on the energy storage DC boost busbar unit, connected to a first energy storage access switch and a second energy storage access switch respectively; The first energy storage access switch sequentially connects the first power electronic transformer high-voltage converter, the high-frequency transformer, the first power electronic transformer low-voltage converter and the first energy storage module; The second energy storage access switch sequentially connects the second power electronic transformer high-voltage converter, the high-frequency transformer, the second power electronic transformer low-voltage converter and the second energy storage module.

2. A thermal power energy storage distributed high voltage direct current convergence segmented frequency modulation system as claimed in claim 1, characterized in that: The energy storage DC boost merging unit includes connecting the DC 28.28kV energy storage busbar to the A section energy storage grid-connected converter and the B section energy storage grid-connected converter in the unit through the A section energy storage DC grid-connected circuit breaker and the B section energy storage DC grid-connected circuit breaker respectively, so that the energy storage electric energy interacts with the generator through the segmented high-voltage conversion device.

3. A thermal power energy storage distributed high voltage direct current convergence segmented frequency modulation system as claimed in claim 2, characterized in that: The segmented frequency modulation system adopts a segmented commutation scheme, using two sets of segmented high-voltage commutation devices, and the two sets of devices perform power regulation control through a connection architecture; One section of energy storage assists the frequency regulation of the first generator or the second generator alone, or assists the frequency regulation of the first and second generators at the same time, to complete the frequency regulation of the auxiliary thermal power unit; The two sets of segmented high-voltage converter devices are a first power electronic transformer high-voltage converter and a second power electronic transformer high-voltage converter.

4. A thermal power energy storage distributed high voltage direct current convergence segmented frequency modulation system as claimed in claim 3, characterized in that: The segmented high-voltage commutation device adopts a virtual impedance AC droop control scheme in the segmented high-voltage commutation device, establishes voltage active power and frequency reactive power droop control equations, and adopts adaptive virtual impedance to compensate for the voltage active power droop coefficient, so that the frequency regulation performance of the two sets of segmented high-voltage commutation devices to assist the thermal power generation units is optimized; Adopting an adaptive DC droop control scheme in each energy storage grid-connected converter, the adaptive DC active voltage droop coefficient is used to adjust the DC voltage regulation range, active power regulation amount and voltage regulation rate; The energy storage grid-connected converter includes a section A energy storage grid-connected converter, a section B energy storage grid-connected converter, a first power electronic transformer high-voltage converter, a first power electronic transformer low-voltage converter, a second power electronic transformer high-voltage converter, and a second power electronic transformer low-voltage converter.

5. A thermal power energy storage distributed high-voltage direct current bus segmented frequency modulation method, using a thermal power energy storage distributed high-voltage direct current bus segmented frequency modulation system as claimed in any one of claims 1 to 4, characterized in that: The electric energy generated by the generator enters the thermal power energy storage segmented commutation access unit through the outlets of the first generator and the second generator; Electric energy enters the energy storage grid-connected converter through the energy storage AC bus, and enters the energy storage DC boost bus unit using a virtual impedance AC droop control scheme to complete power regulation control.

6. A thermal power energy storage distributed high voltage direct current convergence segmented frequency modulation method as claimed in claim 5, characterized in that: The virtual impedance AC droop control scheme is to establish voltage-active power and frequency-reactive power droop control equations, which are expressed as follows: ， in, is the output voltage amplitude of the i-th set of segmented high-voltage converter devices; The output voltage reference value of the i-th set of segmented high-voltage converter devices; is the voltage-active power droop coefficient of the i-th set of segmented high-voltage converter devices; Output / absorb active power for i sets of segmented high-voltage converter devices; Output frequency current value of the i-th set of segmented high-voltage converter devices; Outputting a frequency reference value for the i-th set of segmented high-voltage converter devices; is the frequency-reactive power droop coefficient of the i-th segmented high-voltage converter device; Output / absorb reactive power for the i-th set of segmented high-voltage converter devices.

7. A thermal power energy storage distributed high voltage direct current convergence segmented frequency modulation method as claimed in claim 6, characterized in that: The virtual impedance AC droop control scheme includes using adaptive virtual impedance to compensate for the voltage-active power droop coefficient to improve the active power distribution accuracy. The expression is: ， in, The actual power rating output / absorption of the i-th set of segmented high-voltage converter devices; , The output / absorption actual power rating of the first and second sets of segmented high-voltage converters; is the grid connection point voltage of the i-th set of segmented high-voltage converter devices, i.e., the outlet voltage of #1 and #2 generators; , is the adaptive virtual impedance, is the energy storage output voltage reference value; ， in, It is the active power PI adjustment proportional coefficient.

8. A thermal power energy storage distributed high voltage direct current convergence segmented frequency modulation method as claimed in claim 7, characterized in that: The virtual impedance AC droop control scheme also includes stabilizing the control of the energy storage bus voltage of the energy storage DC boost bus unit, and adopting an adaptive DC active power-voltage droop coefficient in the traditional DC active power voltage droop control method, which is expressed as: ， ， in, is the DC side output voltage of the jth set of energy storage grid-connected converter; is the DC energy storage bus voltage reference value; is the DC active power-voltage droop coefficient in the control system of the j-th energy storage grid-connected converter; is the current value of active power output / absorbed by the jth set of energy storage grid-connected converter; is the target value of active power output / absorption of the jth set of energy storage grid-connected converter, is the fixed voltage droop control coefficient, is the maximum DC voltage adjustment range of the j-th energy storage grid-connected converter; is the maximum active power regulation value of the j-th energy storage grid-connected converter; is the DC voltage regulation rate of the j-th set of energy storage grid-connected converter. When the deviation is larger, the adaptive DC active power-voltage droop coefficient becomes smaller. When facing the same active power regulation amount, the voltage variation range is reduced.

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 a method for segmented frequency regulation of distributed high-voltage direct current bus of thermal power energy storage as described in any one of claims 5 to 8 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 a method for segmented frequency regulation of a distributed high-voltage direct current bus of thermal power energy storage as described in any one of claims 5 to 8 are implemented.

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