Thermal power configuration light storage section combined security power supply method and system

Abstract

The application discloses a thermal power configuration light storage segmented combined security power supply method and system, relates to the technical field of security power supply, and comprises a connection photovoltaic bus, an energy storage bus and a security power supply bus, forming a three-bus system connected through an interconnection circuit breaker; the photovoltaic energy storage system is set as a backup power supply of the security power supply through the interconnection circuit breaker; the photovoltaic energy storage system is connected to a thermal power unit frequency modulation, and meanwhile, the photovoltaic system is used as a controllable load to participate in frequency modulation; a load reduction control strategy is implemented in the photovoltaic system to provide active power support for a power grid. The photovoltaic 400V AC bus, the energy storage 400V AC bus and the 400V security power supply bus are connected through the interconnection circuit breaker, the system makes the photovoltaic energy storage be able to be used as a backup power supply system of the low-voltage 400V security power supply. When the 400V security load does not work or the capacity is insufficient, the system can be rapidly switched to the light storage system for power supply, thereby greatly improving the reliability of the plant low-voltage power supply.

Description

Technical Field

[0001] This invention relates to the field of emergency power supply technology, and in particular to a method and system for configuring a combined solar and energy storage emergency power supply for thermal power plants. Background Technology

[0002] Currently, the typical design of power supply systems for large thermal power units usually includes step-down transformers at the generator outlet. These transformers gradually reduce the voltage from the high voltage at the generator outlet (e.g., 20kV) to the low voltage required by the power supply system (e.g., 6kV and 400V). This design uses power frequency transformers and mainly involves the use of alternating current.

[0003] However, with the continuous increase in unit capacity, the capacity of the plant auxiliary power system is also constantly expanding. The capacity of the high-voltage plant transformer (i.e., the plant auxiliary transformer) increases accordingly, leading to a significant increase in the short-circuit current of the plant auxiliary power system. This places higher demands on the short-circuit breaking capacity of the high-voltage switches. At the same time, in order to meet the requirements of short-circuit thermal stability, the high-voltage cables of the plant auxiliary power system need to be of thicker specifications, which undoubtedly increases investment costs.

[0004] Furthermore, traditional power plant transformers use power frequency transformers, which are bulky and often require capacity expansion when the plant's power supply system capacity needs to be increased. This expansion is costly, time-consuming, and disrupts the power plant's normal power generation.

[0005] Against this backdrop, traditional AC power systems for plant use face several development bottlenecks and urgently require new technological solutions. Compared to traditional AC power systems, DC grid systems are considered to have many advantages. For example, DC grids have a larger power supply capacity, do not require consideration of phase angle and frequency issues, and can achieve asynchronous system interconnection. When plant loads are connected to a DC power system via rectifiers, power conversion efficiency can be improved, equipment losses reduced, and frequency-controlled load driving achieved, thereby simplifying the internal circuitry of the load and reducing failure rates and equipment costs.

[0006] This invention proposes a method and system for configuring a combined photovoltaic and energy storage backup power supply for thermal power plants. The aim is to leverage the advantages of photovoltaic and energy storage systems to solve the problems existing in traditional AC power systems for plant use, thereby improving the reliability and economy of the power system for plant use. Summary of the Invention

[0007] In view of the above-mentioned problems, the present invention is proposed.

[0008] Therefore, the problem this invention aims to solve is: how to address the issue of traditional high-voltage power plant transformers using power frequency transformers, which are bulky and often require capacity expansion when the plant's power supply system capacity needs to be increased. This expansion is costly, time-consuming, and disrupts the power plant's normal power generation.

[0009] To address the aforementioned technical problems, this invention provides the following technical solution: a method for configuring a combined photovoltaic and energy storage backup power supply in thermal power plants, comprising: connecting a photovoltaic bus, an energy storage bus, and a backup power supply bus to form a three-bus system connected by interconnecting circuit breakers; using interconnecting circuit breakers to configure the photovoltaic energy storage system as a backup power source for the backup power supply; connecting the photovoltaic energy storage system to the frequency regulation of the thermal power unit, while simultaneously enabling the photovoltaic system to participate in frequency regulation as a controllable load; implementing a load shedding control strategy in the photovoltaic system to provide active power support to the power grid; the load shedding control strategy includes improving the control system of the plant's photovoltaic inverter, introducing a load shedding control strategy, without changing the main circuit structure or the inverter grid connection strategy.

[0010] As a preferred embodiment of the method for configuring a combined photovoltaic and energy storage backup power supply in thermal power plants according to the present invention, the photovoltaic energy storage system includes constructing a photovoltaic energy storage system for thermal power plants, connecting the photovoltaic AC bus, the energy storage AC bus, and the backup power supply bus through interconnecting circuit breakers, so that the photovoltaic energy storage serves as a backup power supply system for backup power, reducing the plant's power consumption rate, and the energy storage assists the thermal power units in frequency regulation, with the photovoltaic system participating in the frequency regulation of the thermal power units as a controllable load.

[0011] As a preferred embodiment of the method for configuring a combined photovoltaic and energy storage emergency power supply in thermal power plants according to the present invention, the method of using photovoltaic energy storage as a backup power supply system includes using the photovoltaic energy storage system as a backup power supply to provide reliable emergency power supply. When the emergency load is not working or its capacity is insufficient, the power of the photovoltaic energy storage system is transmitted to the emergency power bus by closing the interconnection circuit breaker to ensure the reliability of the plant's low-voltage power supply.

[0012] As a preferred embodiment of the method for configuring a combined solar and energy storage backup power supply in thermal power plants according to the present invention, wherein: the improvement of the plant photovoltaic inverter control system includes, when performing load shedding control in the photovoltaic inverter control system, the active power reserve is expressed as:

[0013] ,

[0014] in, For photovoltaic backup power, For load reduction rate, This refers to the number of photovoltaic arrays connected in parallel. The reference power provided for the main photovoltaic array; the active power reserve required for load shedding control is controlled by... To make changes, that is, to change the active power output by controlling the load shedding rate, and to set... The corresponding relationship is achieved by changing the load shedding rate through detecting fluctuations in the frequency of the plant's photovoltaic bus, thus providing active power support.

[0015] As a preferred embodiment of the method for configuring a combined solar and energy storage power supply for thermal power plants according to the present invention, the load shedding rate includes: in the photovoltaic inverter control system, the frequency of the plant photovoltaic bus voltage is detected by a PLL phase-locked loop, and the load shedding rate is changed according to the frequency change; when the frequency of the plant photovoltaic bus voltage is greater than the rated value, the photovoltaic power generation load shedding rate is increased, i.e., the active power output is reduced; when the frequency of the plant photovoltaic bus voltage is less than the rated value, the load shedding rate is reduced, i.e., the active power output is increased; the same frequency regulation range as the thermal power unit is achieved; a primary frequency regulation dead zone is set in the frequency control link of the photovoltaic inverter; different load shedding rates are set according to different frequency drop depths to achieve dynamic frequency regulation.

[0016] As a preferred embodiment of the method for configuring a combined solar-storage emergency power supply in thermal power plants according to the present invention, the load reduction rate is expressed as:

[0017] ,

[0018] in, Where is the output frequency of the photovoltaic inverter, and F is the relationship between the load shedding rate and the frequency in the corresponding range. , These represent the maximum and minimum allowed frequencies, respectively. Indicates the normal frequency fluctuation range. This is the standard value for the load reduction rate. To achieve the minimum load reduction rate, This is a calculated value for the load reduction rate over a wide range of frequency fluctuations. This is a calculated value for the load reduction rate based on small-range frequency fluctuations. This represents the maximum load reduction rate.

[0019] Another objective of this invention is to provide a system for configuring a combined solar and energy storage power supply for thermal power plants, which solves the problem of configuring a combined solar and energy storage power supply for thermal power plants by constructing a combined solar and energy storage power supply system for thermal power plants.

[0020] To solve the above-mentioned technical problems, the present invention provides the following technical solution: a combined solar-storage emergency power supply system for thermal power plants, comprising a thermal power plant start-up and standby transformer unit and a distributed photovoltaic energy storage emergency access unit; in the thermal power plant start-up and standby transformer unit, the generator is connected to the power grid system through a main transformer, and a high-voltage transformer is arranged at the generator outlet to step down the voltage and connect to the power plant bus; the power grid system is connected to the high-voltage side of the start-up standby transformer, which steps down the voltage, and the low-voltage side of the start-up standby transformer is connected to the power plant bus; in the distributed photovoltaic energy storage emergency access unit, the power plant bus is connected to the thermal power plant start-up and standby transformer. In the unit, on the low-voltage side of the plant service high-voltage transformer and the starting standby transformer, the photovoltaic panels are connected to the photovoltaic bus via the inverter, the energy storage modules are connected to the energy storage bus via the converter, and the security load is connected to the security power bus via the security load access switch. The photovoltaic AC bus, the energy storage AC bus, and the security power bus are connected through interconnecting circuit breakers. The photovoltaic AC bus is connected to the low-voltage side of the photovoltaic step-up transformer, and the high-voltage side of the photovoltaic step-up transformer is connected to the plant service bus. The energy storage AC bus is connected to the low-voltage side of the energy storage step-up transformer, and the high-voltage side of the energy storage step-up transformer is connected to the plant service bus. The security power bus is connected to the low-voltage side of the low-voltage plant transformer, and the high-voltage side of the low-voltage plant transformer is connected to the plant service bus.

[0021] A computer device includes a memory and a processor, the memory storing a computer program, and the processor executing the computer program to implement the steps of the method for configuring a combined solar and energy storage power supply for thermal power plants as described above.

[0022] A computer-readable storage medium having a computer program stored thereon, which, when executed by a processor, implements the steps of the method for configuring a combined solar and energy storage power supply for thermal power plants as described above.

[0023] The beneficial effects of this invention are as follows: The method for configuring a combined solar and energy storage emergency power supply in thermal power plants provided by this invention brings many beneficial effects, which are detailed below:

[0024] 1) Improve power supply reliability and flexibility:

[0025] By connecting the 400V AC busbar for photovoltaic power, the 400V AC busbar for energy storage, and the 400V backup power busbar through interconnecting circuit breakers, this system enables photovoltaic energy storage to serve as a backup power system for the low-voltage 400V backup power supply. When the 400V backup load is not working or its capacity is insufficient, the system can quickly switch to power from the photovoltaic and energy storage system, thereby greatly improving the reliability of the plant's low-voltage power supply.

[0026] 2) Reduce plant power consumption and costs:

[0027] Configuring photovoltaic (PV) and energy storage devices in plant power systems can effectively reduce reliance on traditional power sources, thereby lowering the plant's power consumption rate. Simultaneously, the introduction of PV and energy storage can optimize power load distribution, reduce peak-hour power demand, and help lower electricity costs.

[0028] 3) Supports frequency regulation of thermal power units and grid stability:

[0029] Energy storage devices can serve not only as backup power sources but also as auxiliary power sources for frequency regulation in thermal power units. When grid frequency fluctuates, energy storage devices can respond rapidly, releasing or absorbing electrical energy to help maintain grid frequency stability. Furthermore, photovoltaic systems can also participate as controllable loads in the frequency regulation of thermal power units, further enhancing grid stability.

[0030] 4) Simplify circuit structure and reduce failure rate:

[0031] Compared to traditional AC plant power systems, the DC grid configuration proposed in this invention offers numerous advantages. DC grids eliminate the need to consider phase angle and frequency, enabling asynchronous system interconnection. Plant loads are connected to the DC plant power system via rectifiers, simplifying circuit structure, reducing equipment losses, and lowering the failure rate.

[0032] 5) Improve power conversion efficiency and equipment utilization:

[0033] DC grid configurations can also improve power conversion efficiency because DC power experiences less loss during transmission. Furthermore, the introduction of photovoltaic and energy storage devices can make the plant's power system more efficient in terms of equipment utilization, reducing idle time and waste. Attached Figure Description

[0034] To more clearly illustrate the technical solutions of the embodiments of the present invention, the drawings used in the following description of the embodiments will be briefly introduced. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0035] Figure 1 The flowchart illustrates the method for configuring a combined solar-storage and thermal power supply for thermal power plants according to the first embodiment of the present invention.

[0036] Figure 2 The diagram shows the structure of a combined solar-storage and thermal power system for thermal power plants, as provided in the second embodiment of the present invention.

[0037] In the diagram: 100, Thermal power plant start-up and standby transformer unit; 200, Distributed photovoltaic energy storage safety section access unit; 101, Generator #1; 102, Main Transformer #1; 103, 330kV power grid system; 104, Plant service high-voltage transformer; 105, Start-up standby transformer; 201, 6kV plant service busbar; 202, Photovoltaic connection high-voltage side switch; 203, Photovoltaic step-up transformer; 204, Photovoltaic connection low-voltage side switch; 205, 400V photovoltaic busbar; 206, Photovoltaic grid-connection switch; 207, Photovoltaic inverter. 208. Photovoltaic panel; 209. Switch for interconnecting photovoltaic low-voltage busbar and energy storage low-voltage busbar; 210. Switch for connecting energy storage photovoltaic high-voltage side; 211. Energy storage step-up transformer; 212. Switch for connecting energy storage low-voltage side; 213. Energy storage switch; 214. AC cabinet for energy storage system; 215. Energy storage module; 216. Switch for interconnecting energy storage low-voltage busbar and security power supply busbar; 217. Switch for high-voltage side of low-voltage transformer; 218. Low-voltage transformer; 219. Switch for low-voltage side of low-voltage transformer; 220. Switch for connecting security load; 221. Security load. Detailed Implementation

[0038] To make the above-mentioned objects, features and advantages of the present invention more apparent and understandable, the specific embodiments of the present invention will be described in detail below with reference to the accompanying drawings.

[0039] Many specific details are set forth in the following description in order to provide a full understanding of the invention. However, the invention may also be practiced in other ways different from those described herein, and those skilled in the art can make similar extensions without departing from the spirit of the invention. Therefore, the invention is not limited to the specific embodiments disclosed below.

[0040] Example 1, referring to Figure 1 This is the first embodiment of the present invention, which provides a method for configuring a combined photovoltaic and energy storage backup power supply in a thermal power plant, including: connecting a photovoltaic bus, an energy storage bus, and a backup power supply bus to form a three-bus system connected by interconnecting circuit breakers; setting the photovoltaic energy storage system as a backup power supply for the backup power supply through the interconnecting circuit breakers; connecting the photovoltaic energy storage system to the frequency regulation of the thermal power unit, while simultaneously enabling the photovoltaic system to participate in frequency regulation as a controllable load; and implementing a load shedding control strategy in the photovoltaic system to provide active power support to the power grid.

[0041] S1 connects the photovoltaic bus, energy storage bus, and security power bus to form a three-bus system with interconnected circuit breakers.

[0042] S2. By using interconnecting circuit breakers, the photovoltaic energy storage system is set as a backup power source for the emergency power supply.

[0043] A photovoltaic energy storage system for thermal power plants is constructed by connecting the photovoltaic AC bus, the energy storage AC bus, and the backup power bus through interconnecting circuit breakers. This allows the photovoltaic energy storage to serve as a backup power system for backup power, reducing the plant's power consumption rate. The energy storage assists the thermal power units in frequency regulation, and the photovoltaic system participates in the frequency regulation of the thermal power units as a controllable load.

[0044] Specifically, a photovoltaic energy storage system for thermal power plants is constructed by connecting the photovoltaic 400V AC bus, the energy storage 400V AC bus, and the 400V backup power bus through interconnecting circuit breakers. This allows the photovoltaic energy storage to serve as a low-voltage 400V backup power system, reduce the plant's power consumption rate, assist the thermal power units in frequency regulation, and allow the photovoltaic system to participate in the frequency regulation of the thermal power units as a controllable load.

[0045] S3. Connect the photovoltaic energy storage system to the frequency regulation of the thermal power unit, and at the same time make the photovoltaic system participate in the frequency regulation as a controllable load.

[0046] The photovoltaic energy storage system is used as a backup power source for the emergency power supply, ensuring the reliability of the emergency power supply. When the emergency load is not working or its capacity is insufficient, the power of the photovoltaic energy storage system is transmitted to the emergency power bus by closing the interconnection circuit breaker, thus ensuring the reliability of the plant's low-voltage power supply.

[0047] Specifically, by connecting the 400V AC busbar of photovoltaic power, the 400V AC busbar of energy storage, and the 400V backup power busbar through an interconnecting circuit breaker, the photovoltaic-energy storage system can be used as a backup power source for the 400V backup power supply, ensuring the reliability of the backup power supply. When the 400V backup load is not working or its capacity is insufficient, the power of the photovoltaic-energy storage system can be transferred to the 400V backup power busbar by closing the interconnecting circuit breaker, thus ensuring the reliability of the plant's low-voltage power supply.

[0048] Configuring photovoltaic and energy storage systems in plant power systems can reduce plant power consumption rates. Energy storage can assist thermal power units in frequency regulation, and photovoltaic systems can also participate in the frequency regulation of thermal power units as a controllable load.

[0049] S4. Implement load shedding control strategies in photovoltaic systems to provide active power support to the power grid.

[0050] Improvements were made to the control system of the photovoltaic inverter for plant use, and a load reduction control strategy was introduced to enable the photovoltaic power station to support the frequency of the plant bus without changing the main circuit structure or the inverter grid connection strategy.

[0051] When performing load shedding control in the photovoltaic inverter control system, the active power reserve is:

[0052] ,

[0053] in, For photovoltaic backup power, For load reduction rate, This refers to the number of photovoltaic arrays connected in parallel. The reference power provided for the main photovoltaic array; the active power reserve required for load shedding control is controlled by... To make changes, that is, to change the active power output by controlling the load shedding rate, and to set... The corresponding relationship can be achieved by changing the load shedding rate by detecting the fluctuation of the frequency of the 400V busbar of the plant photovoltaic system, thus enabling active power support.

[0054] In the photovoltaic inverter control system, a PLL (phase-locked loop) detects the current frequency of the 400V bus voltage of the plant's photovoltaic system. The shedding rate is adjusted according to frequency changes, enabling the plant's photovoltaic system to actively support system frequency. When the frequency of the 400V bus voltage of the plant's photovoltaic system is higher than the rated value, the photovoltaic shedding rate is increased, thus reducing active power output. Conversely, when the frequency of the 400V bus voltage of the plant's photovoltaic system is lower than the rated value, the shedding rate is decreased, thus increasing active power output, providing inertia for the system. To achieve the same frequency regulation range as thermal power units, a primary frequency dead zone is set in the frequency control stage of the photovoltaic inverter. Different shedding rates are set according to different frequency drop depths to achieve dynamic frequency adjustment. The shedding rate is expressed as:

[0055] ,

[0056] in, Where is the output frequency of the photovoltaic inverter, and F is the relationship between the load shedding rate and the frequency in the corresponding range. , These represent the maximum and minimum allowed frequencies, respectively. Indicates the normal frequency fluctuation range. This is the standard value for the load reduction rate. To achieve the minimum load reduction rate, This is a calculated value for the load reduction rate over a wide range of frequency fluctuations. This is a calculated value for the load reduction rate based on small-range frequency fluctuations. This represents the maximum load reduction rate.

[0057] The allowable frequency deviation for the power system is ±0.2Hz, therefore, the following settings are made: At this time, the load reduction rate ,Pick This allows the system to operate in maximum power point tracking mode, where all the power stored by the photovoltaic system is fed back to the system through load shedding, thus balancing the system power. When the system frequency is greater than 50.2 Hz, the load shedding rate is set to the maximum to reduce the active power output to the system. This invention sets... The normal fluctuation range of the system is set as follows: ,Right now During this interval, the system operates at a fixed load reduction rate, making . , To connect within the corresponding interval , Linear function, set , .

[0058] Example 2, refer to Figure 2 This is the second embodiment of the present invention, which differs from the previous embodiment in that it provides a combined emergency power supply system for thermal power plants with photovoltaic and energy storage sections, including: a standby transformer unit 100 for thermal power plants and a distributed photovoltaic energy storage emergency access section unit 200.

[0059] In the thermal power plant's start-up and standby transformer unit 100, the generator is connected to the 330kV power grid system via the main transformer. A plant service high-voltage transformer is installed at the generator outlet to step down the 20kV voltage to 6kV and connect it to the 6kV plant service bus. The 330kV power grid system is connected to the high-voltage side of the start-up standby transformer, which steps down the 330kV voltage to 6kV. The low-voltage side of the start-up standby transformer is connected to the 6kV plant service bus.

[0060] In the distributed photovoltaic energy storage security section access unit 200, the 6kV plant service bus is connected to the low-voltage side of the plant service high-voltage transformer and the starting standby transformer in the thermal power plant standby transformer unit 100. The photovoltaic panels are connected to the 400V photovoltaic bus via inverters, and the energy storage modules are connected to the 400V energy storage bus via converters. The security load is connected to the 400V security power bus via a security load access switch. The photovoltaic 400V AC bus, the energy storage 400V AC bus, and the 400V security power bus are connected through interconnecting circuit breakers. The photovoltaic 400V AC bus is connected to the low-voltage side of the photovoltaic step-up transformer. The high-voltage side of the photovoltaic step-up transformer is connected to the 6kV plant service bus. The energy storage 400V AC bus is connected to the low-voltage side of the energy storage step-up transformer. The high-voltage side of the energy storage step-up transformer is connected to the 6kV plant service bus. The 400V security power bus is connected to the low-voltage side of the low-voltage plant transformer. The high-voltage side of the low-voltage plant transformer is connected to the 6kV plant service bus.

[0061] like Figure 2 As shown, 101 is generator #1, 102 is main transformer #1, 103 is the 330kV power grid system, 104 is the plant's high-voltage transformer, and 105 is the start-up standby transformer.

[0062] 201 is the 6kV plant service busbar; 202 is the photovoltaic high-voltage side switch; 203 is the photovoltaic step-up transformer; 204 is the photovoltaic low-voltage side switch; 205 is the 400V photovoltaic busbar; 206 is the photovoltaic grid-connection switch; 207 is the photovoltaic inverter; 208 is the photovoltaic panel; 209 is the interconnection switch between the photovoltaic low-voltage busbar and the energy storage low-voltage busbar; 210 is the energy storage photovoltaic high-voltage side switch; 211 is the energy storage step-up transformer; 212 is the energy storage low-voltage side switch; 213 is the energy storage switch; 214 is the energy storage system AC cabinet; 215 is the energy storage module; 216 is the interconnection switch between the energy storage low-voltage busbar and the security power supply busbar; 217 is the low-voltage plant transformer high-voltage side switch; 218 is the low-voltage plant transformer; 219 is the low-voltage plant transformer low-voltage side switch; 220 is the security load connection switch; 221 is the security load.

[0063] If the aforementioned functions are implemented as 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 this invention, essentially, or the part that contributes to the prior art, or a portion of the 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 to cause a computer device (which may be a personal computer, server, or network device, etc.) to execute all or part of the steps of the methods described in the various embodiments of this invention. The aforementioned storage medium includes various media capable of storing program code, such as USB flash drives, portable hard drives, read-only memory (ROM), random access memory (RAM), magnetic disks, or optical disks.

[0064] The logic and / or steps represented in the flowchart or otherwise described herein, for example, can be considered as a sequenced list of executable instructions for implementing logical functions, and can be embodied in any computer-readable medium for use by, or in conjunction with, an instruction execution system, apparatus, or device (such as a computer-based system, a processor-including system, or other system that can fetch and execute instructions from, an instruction execution system, apparatus, or device). For the purposes of this specification, "computer-readable medium" can be any means that can contain, store, communicate, propagate, or transmit programs for use by, or in conjunction with, an instruction execution system, apparatus, or device.

[0065] More specific examples of computer-readable media (a non-exhaustive list) include: electrical connections (electronic devices) having one or more wires, portable computer disk drives (magnetic devices), random access memory (RAM), read-only memory (ROM), erasable and editable read-only memory (EPROM or flash memory), fiber optic devices, and portable optical disc read-only memory (CDROM). Furthermore, computer-readable media 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 medium, followed by editing, interpreting, or otherwise processing as necessary, and then stored in computer memory.

[0066] It should be understood that various parts of the present invention can be implemented in hardware, software, firmware, or a combination thereof. In the above embodiments, multiple steps or methods can be implemented in software or firmware stored in memory and executed by a suitable instruction execution system. For example, if implemented in hardware, as in another embodiment, it can be implemented using any one or a combination of the following techniques known in the art: discrete logic circuits having logic gates for implementing logical functions on data signals, application-specific integrated circuits (ASICs) having suitable combinational logic gates, 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 are not intended to limit it. Although the present invention has been described in detail with reference to preferred embodiments, those skilled in the art should understand that modifications or equivalent substitutions can be made to the technical solutions of the present invention without departing from the spirit and scope of the technical solutions of the present invention, and all such modifications or substitutions should be covered within the scope of the claims of the present invention.

Claims

1. A method for configuring a combined solar-storage emergency power supply in thermal power plants, characterized in that: include, Connecting the photovoltaic busbar, energy storage busbar, and security power busbar to form a three-busbar system with interconnected circuit breakers; By using interconnecting circuit breakers, the photovoltaic energy storage system can be set as a backup power source for the emergency power supply; Integrate photovoltaic energy storage systems into the frequency regulation of thermal power units, and at the same time enable photovoltaic systems to participate in frequency regulation as controllable loads; Implement load shedding control strategies in photovoltaic systems to provide active power support to the power grid; The load reduction control strategy includes improving the control system of the plant photovoltaic inverter and introducing a load reduction control strategy without changing the main circuit structure or the inverter grid connection strategy. The photovoltaic energy storage system includes constructing a photovoltaic energy storage system for thermal power plants, connecting the photovoltaic AC bus, the energy storage AC bus, and the backup power bus through interconnecting circuit breakers, so that the photovoltaic energy storage serves as a backup power system for backup power, reducing the plant's power consumption rate, and the energy storage assists the thermal power units in frequency regulation, with the photovoltaic system participating in the frequency regulation of the thermal power units as a controllable load. The photovoltaic energy storage system as a backup power source for emergency power supply includes using the photovoltaic energy storage system as a backup power source for emergency power supply to ensure the reliability of emergency power supply. When the emergency load is not working or its capacity is insufficient, the power of the photovoltaic energy storage system is transmitted to the emergency power supply bus by closing the interconnection circuit breaker to ensure the reliability of the plant's low-voltage power supply. The improvement to the plant photovoltaic inverter control system includes, when implementing load shedding control in the photovoltaic inverter control system, expressing the active power reserve as follows: ΔP=σN s P ref Where ΔP is the photovoltaic backup power, σ is the load shedding rate, and N s P represents the number of photovoltaic arrays connected in parallel. ref Reference power provided for the main photovoltaic array; The active power reserve required for load shedding control is changed by controlling σ, that is, by controlling the load shedding rate to change the active power output, setting the f-σ correspondence, and changing the load shedding rate by detecting the fluctuation of the plant photovoltaic bus frequency to achieve active power support.

2. The method for configuring a combined solar-storage emergency power supply for thermal power plants as described in claim 1, characterized in that: The load shedding rate is included in the photovoltaic inverter control system, which detects the frequency of the plant photovoltaic bus voltage through a PLL phase-locked loop and changes the load shedding rate according to the frequency change. When the voltage frequency of the photovoltaic busbar is greater than the rated value, the photovoltaic power generation unloading rate is increased, which means reducing the active power output. When the voltage frequency of the photovoltaic busbar is less than the rated value, the unloading rate is reduced, which means increasing the active power output. To achieve the same frequency regulation range as thermal power units, a primary frequency regulation dead zone is set in the frequency control stage of the photovoltaic inverter. Different load shedding rates are set according to different frequency drop depths to achieve dynamic frequency regulation.

3. The method for configuring a combined solar-storage emergency power supply for thermal power plants as described in claim 2, characterized in that: The load reduction rate is expressed as follows: Where f is the output frequency of the photovoltaic inverter, and F is the relationship between the load shedding rate and the frequency in the corresponding interval. max f min These represent the maximum and minimum allowed frequencies, f and f, respectively. low -f high Indicates the normal frequency fluctuation range, k N k is the standard value for the load reduction rate. min F1(f) is the minimum load reduction rate, F2(f) is the calculated load reduction rate over a large frequency fluctuation range, and F2(f) is the calculated load reduction rate over a small frequency fluctuation range. k max This represents the maximum load reduction rate.

4. A system employing the method for configuring a combined solar-storage emergency power supply in thermal power plants as described in any one of claims 1 to 3, characterized in that: This includes a thermal power plant start-up and standby transformer unit (100) and a distributed photovoltaic energy storage security section access unit (200); In the thermal power plant start-up and standby transformer unit (100), the generator is connected to the power grid system through the main transformer. A plant high-voltage transformer is arranged at the generator outlet to step down the voltage and connect to the plant bus. The power grid system is connected to the high-voltage side of the start-up standby transformer. The start-up standby transformer steps down the voltage and the low-voltage side of the start-up standby transformer is connected to the plant bus. The plant bus in the distributed photovoltaic energy storage security section access unit (200) is connected to the low-voltage side of the plant high-voltage transformer and the starting standby transformer in the thermal power plant standby transformer unit (100). The photovoltaic panels are connected to the photovoltaic bus through the inverter, the energy storage modules are connected to the energy storage bus through the converter, and the security load is connected to the security power bus through the security load access switch. The photovoltaic AC bus, the energy storage AC bus and the security power bus are connected through the interconnection circuit breaker. The photovoltaic AC bus is connected to the low-voltage side of the photovoltaic step-up transformer, the high-voltage side of the photovoltaic step-up transformer is connected to the plant bus, the energy storage AC bus is connected to the low-voltage side of the energy storage step-up transformer, the high-voltage side of the energy storage step-up transformer is connected to the plant bus, the security power bus is connected to the low-voltage side of the low-voltage plant transformer, and the high-voltage side of the low-voltage plant transformer is connected to the plant bus.

5. A computer device comprising a memory and a processor, wherein the memory stores a computer program, characterized in that: When the processor executes the computer program, it implements the steps of the method for configuring a combined solar-storage and thermal power supply in thermal power plants as described in any one of claims 1 to 3.

6. A computer-readable storage medium having a computer program stored thereon, characterized in that: When the computer program is executed by the processor, it implements the steps of the method for configuring a combined solar-storage and thermal power supply in thermal power plants as described in any one of claims 1 to 3.

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