Carbon dioxide energy storage power station system
By employing a multi-level modular electrical wiring structure and a variable frequency starter, the complexity and reliability issues of compressed carbon dioxide energy storage power stations are resolved, achieving efficient and reliable power conversion and system expansion, making it suitable for large-capacity compressed carbon dioxide energy storage power stations.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2025-12-02
- Publication Date
- 2026-04-07
AI Technical Summary
Existing compressed carbon dioxide energy storage power stations have complex electrical wiring structures, low efficiency, and insufficient reliability, making it difficult to adapt to the needs of high power and wide load variations.
It adopts a multi-level, modular electrical wiring structure, including high-voltage power distribution equipment, energy release main transformer, energy storage transformer, energy release generator, circuit breaker and compressor. The decoupling of compression energy storage and expansion energy release is achieved through frequency conversion starting device and current limiting reactor. The modular design and redundant power supply simplify the grid connection process and improve system reliability and scalability.
It achieves efficient decoupling of energy storage and energy release operations, improves system flexibility and security, simplifies grid peak-shaving response, reduces equipment costs, and improves the reliability and economy of power plants. It is suitable for large-scale energy storage power plants with a capacity of hundreds of megawatts.
Smart Images
Figure CN121813701A_ABST
Abstract
Description
TECHNICAL FIELD
[0001] The present application relates to the technical field of compressed carbon dioxide energy storage, in particular to an electrical wiring structure suitable for large-capacity compressed carbon dioxide energy storage power station. BACKGROUND
[0002] New energy storage technology is an important measure to solve the safe and stable operation of high-proportion renewable energy power grids and is also an indispensable means of power transfer. Compressed carbon dioxide energy storage is a new large-scale physical energy storage technology that realizes electric energy storage and release through compressed / expanding CO2. It compresses carbon dioxide at night during the low valley voltage of the power grid to store it in liquid form in a liquid tank. During the daytime peak electricity consumption period, high-pressure carbon dioxide is released from the liquid tank to be delivered to a carbon dioxide turbine to generate power, and the expanded carbon dioxide at normal pressure is stored in a gas tank. Compressed CO2 energy storage power stations have advantages such as high energy density, long service life, and environmental friendliness, and are mainly used in power grid peak shaving and renewable energy consumption fields. However, the existing electrical wiring structure has problems such as complex structure, low efficiency, and insufficient reliability, making it difficult to meet the high-power and wide-load variation requirements of the CO2 energy storage system.
[0003] Therefore, the present application provides an efficient, reliable, and large-capacity compressed carbon dioxide energy storage power station electrical wiring structure that optimizes electric energy conversion efficiency and improves system reliability and economy. SUMMARY
[0004] The technical problem to be solved by the present application is to provide a carbon dioxide energy storage power station system that is suitable for large-capacity compressed carbon dioxide energy storage power stations and has multi-level, modular structure and high efficiency and reliability.
[0005] To solve the above technical problems, the technical solution adopted by the present application is as follows: A carbon dioxide energy storage power station system includes a high-voltage power distribution device, an energy release main transformer, an energy storage transformer, an energy release generator, a circuit breaker, an energy storage system mainly including a compressor, and an energy release system mainly composed of an energy release generator and an energy release main transformer. The energy release main transformer and the energy storage transformer are respectively connected in parallel with the high-voltage power distribution device. The compressor includes a low-pressure compressor and a high-pressure compressor. The low-pressure compressor is connected to one outgoing winding of the energy storage transformer through a low-pressure compressor outlet circuit breaker, and the high-pressure compressor is connected to another outgoing winding of the energy storage transformer through a high-pressure compressor outlet circuit breaker. The compressor uses a variable frequency starting device.
[0006] A further improvement of the technical solution of the present application is that the low-pressure compressor and the high-pressure compressor are started by the same set of variable frequency starting devices, and the variable frequency starting device is connected in parallel with the high-pressure compressor and the high-pressure compressor outlet circuit breaker through a variable frequency starting device outlet circuit breaker.
[0007] Further improvement of the technical scheme of the present application is that the high-voltage compressor and the outlet circuit breaker of the variable frequency starting device are further connected between an outlet winding of the energy storage transformer and the outlet circuit breaker of the high-voltage compressor and the variable frequency starting device.
[0008] Further improvement of the technical scheme of the present application is that at least two sets of energy storage systems are provided, and the energy storage transformers of each set of energy storage systems are connected in parallel on the high-voltage power distribution device.
[0009] Further improvement of the technical scheme of the present application is that the energy storage transformers of each energy storage system are further connected to the outlet winding of the high-voltage compressor and are respectively connected in parallel with a current limiting reactor, and the current limiting reactors of each energy storage system are further connected through a respective auxiliary branch circuit breaker and an energy storage system auxiliary bus tie switch.
[0010] Further improvement of the technical scheme of the present application is that the variable frequency starting device of each energy storage system is separately provided in a different room from other equipment of the energy storage system.
[0011] Due to the adoption of the above technical scheme, the present application has achieved the following technical progress: 1. Efficient decoupling of energy storage and energy release conditions, improving system flexibility. The present application uses special transformers (energy storage transformers and energy release main transformers) to realize the decoupling of compression energy storage and expansion energy release, avoiding the risk of short circuit or reverse power supply during mode switching, ensuring the stability of the electrical system during mode switching, and improving the safety of the system.
[0012] The present application uses high-voltage power distribution devices as a unified interface, simplifies the grid connection process, supports fast switching, adapts to grid peak shaving demand, and improves the response speed of the power station.
[0013] In the energy storage mode, the energy storage transformer directly supplies power to the compressor and auxiliary equipment, without the need for the energy release main transformer to operate, thereby reducing the loss. In the energy release mode, the energy release generator is directly boosted to the grid voltage through the energy release main transformer, avoiding multi-stage switching of auxiliary power, and achieving higher efficiency.
[0014] 2. Modular wiring scheme, improving scalability and reliability The energy storage transformer independently configured for each set of energy storage system is a load regulating step-down transformer, the high-voltage compressor, the low-voltage compressor, and the auxiliary power are connected by independent busbars and controlled by independent circuit breakers, realizing physical isolation and improving system reliability and independence. The independent busbars used in the present application can supply power in segments and start the high-voltage / low-voltage compressor in stages, avoiding large current surges when starting simultaneously. Each bus segment is provided with independent relay protection devices (such as differential protection and overcurrent protection), and fault location and removal are faster.
[0015] The high-pressure compressor and the low-pressure compressor are divided into different busbars, and can be flexibly switched according to the working condition. When one compression line is shut down for maintenance, the other lines can still work normally, thereby guaranteeing the overall availability of the power station.
[0016] The modular unit is formed, so that the construction or capacity expansion can be realized in stages. By increasing the compressor module and the corresponding busbar section, the GW-level capacity can be flexibly expanded, and the electrical structure does not need to be significantly changed.
[0017] The sections of the auxiliary bus are interconnected and redundant, and each two auxiliary busbars of the energy storage system are used as backup for each other, so that the power supply reliability is improved.
[0018] 3. Accurate control of short-circuit current, reduction of equipment cost and enhancement of safety The current limiting reactor is additionally arranged in front of the auxiliary bus, so that the short-circuit current is limited within 40 kA, the bus voltage drop is less than or equal to 5%, the short-circuit capacity requirement of the switch device is reduced, and the cost is saved.
[0019] 4. Overall optimization of the system, and remarkable comprehensive benefits The current limiting measure and the redundant power supply are adopted in the application, so that the system reliability is improved while the cost is reduced. The application reduces the coupling of the energy storage / energy release working conditions, reduces the operation complexity, and improves the safety. The modular design is adopted, so that the maintenance and capacity expansion are facilitated, and the application is suitable for the hundreds of megawatt-level and above large energy storage power stations. The application is particularly suitable for the hundreds of megawatt-level compressed carbon dioxide energy storage power stations, can significantly improve the economy, the reliability and the grid adaptability, and helps the construction of new power systems. BRIEF DESCRIPTION OF DRAWINGS
[0020] Figure 1 is the main wiring structure diagram of the compressed carbon dioxide energy storage power station of the application; Figure 2 is the arrangement and connection busbar arrangement diagram of the high-voltage power distribution device of the application; Among them, 1, high-voltage power distribution device, 2, energy release main transformer, 3, energy storage transformer, 4, energy release generator, 5, low-pressure compressor, 6, high-pressure compressor, 7, current limiting reactor, 8, low-pressure compressor outlet circuit breaker, 9, high-pressure compressor and variable frequency starting device outlet circuit breaker, 10, auxiliary branch circuit breaker, 11, energy storage system auxiliary bus tie switch, 12, high-pressure compressor outlet circuit breaker, 13, variable frequency starting device outlet circuit breaker, 14, variable frequency starting device. DETAILED DESCRIPTION
[0021] The carbon dioxide energy storage power station system of the present application comprises a high-voltage power distribution device 1, a discharge main transformer 2, a discharge generator 4, an energy storage transformer 3, a current-limiting reactor 7, an energy storage system mainly composed of compressors, and circuit breakers for connecting the devices; the discharge generator 4 is connected with the discharge main transformer 2 to form a discharge system. The energy storage system is provided with at least two sets, and the energy storage transformer 3 of each set of energy storage system is connected in parallel on the high-voltage power distribution device 1, so that the capacity can be expanded indefinitely.
[0022] The discharge main transformer 2 and the energy storage transformer 3 are connected in parallel with the high-voltage power distribution device 1; the compressor of each set of energy storage system comprises a low-pressure compressor 5 and a high-pressure compressor 6, the low-pressure compressor 5 is connected with one outgoing winding of the energy storage transformer 3 through a low-pressure compressor outlet circuit breaker 8, and the high-pressure compressor 6 is connected with another outgoing winding of the energy storage transformer 3 through a high-pressure compressor outlet circuit breaker 12.
[0023] The compressor adopts variable frequency starting, the low-pressure compressor 5 and the high-pressure compressor 6 adopt one-drag-two starting of the same set of variable frequency starting device 14, the variable frequency starting device 14 is connected with one winding at the outgoing end of the energy storage transformer 3 through a variable frequency starting device outlet circuit breaker 13, and the variable frequency starting device 14 and the variable frequency starting device outlet circuit breaker 13 are connected in parallel with the high-pressure compressor 6 and the high-pressure compressor outlet circuit breaker 12 thereof. A high-pressure compressor and variable frequency starting device outlet circuit breaker 9 is further connected between the variable frequency starting device outlet circuit breaker 13 and the high-pressure compressor outlet circuit breaker 12 in front of the variable frequency starting device outlet circuit breaker 13 and the outgoing winding of the energy storage transformer 3. The variable frequency starting device 14 of each energy storage system can be placed in a room alone, and other devices of the energy storage system are arranged separately in different rooms.
[0024] The outgoing winding of the high-pressure compressor 6 of each energy storage system is further connected with the current-limiting reactor 7 in parallel, and the current-limiting reactor 7 is in parallel relationship with the high-pressure compressor 6, and the current-limiting reactors 7 of each energy storage system are further connected with each other through independent plant branch circuit breakers 10 and energy storage system plant bus tie switches 11. Figure 1 The connection structure of the present application of the two sets of energy storage systems is shown, and the two sets of energy storage systems are connected with each other through the current-limiting reactors 7, the plant branch circuit breakers 10, and the energy storage system plant bus tie switches 11.
[0025] The energy releasing system and the energy storage system of the carbon dioxide energy storage power station system of the application are decoupled through the energy storage transformer 3 and the energy releasing main transformer 2, the high-voltage power distribution device 1 serves as the unified interface of the energy storage transformer and the energy releasing main transformer, and the functions of power collection and distribution in the energy storage and energy releasing conditions are considered, so that the grid connection process is simplified. In the energy storage condition, the high-voltage power distribution device 1 in the power station sends power to each compressor and the station auxiliary bus section through the energy storage transformer 3 to drive each compressor and its auxiliary equipment to work, so that the energy storage operation is realized; the auxiliary equipment and non-production power not mentioned in the application are taken from the station auxiliary bus section of the energy storage system. In the energy releasing condition, the energy releasing generator 4 is driven by the CO2 expander to generate power, the power is connected to the high-voltage power distribution device 1 through the energy releasing main transformer 2, and then is sent to the upper-level collection station. The above two conditions are operated in time periods, the energy releasing generator, the energy releasing main transformer and the energy storage transformer can be effectively decoupled, the intelligent scheduling of the high-voltage power distribution device 1 can realize the quick switching of the energy storage and energy releasing conditions, adapt to the power grid peak shaving demand, and improve the response speed of the power station.
[0026] The application can realize a modularized wiring scheme: one energy storage transformer 3 is configured for each set of energy storage system, the energy storage transformer 3 is a split step-down transformer with on-load voltage regulation, two independent outgoing winding groups are branched from the low-voltage side of the energy storage transformer 3, one outgoing winding group is connected with the bus section of the low-voltage compressor 5, and the other outgoing winding group is connected with the bus section of a high-voltage compressor 6 and a station auxiliary bus section, each bus section is provided with an independent circuit breaker control to realize physical isolation. The bus section of the low-voltage compressor 5 is taken from the low-voltage winding group A of the energy storage transformer, and the bus section of the high-voltage compressor (including the power supply of the compressor variable frequency starting device) and the power supply of the station auxiliary bus section are taken from the winding group B of the energy storage transformer, each energy storage system forms an independent unit, which is convenient for phased construction or capacity expansion, and the newly added energy storage system only needs to copy the same wiring structure.
[0027] The station auxiliary bus current limiting wiring scheme of the application is that the energy storage transformer 3 is of the on-load voltage regulation type, a current limiting reactor (which can be a common current limiting reactor or a deep current limiting reactor device) is arranged at the front end of the station auxiliary bus section, the short-circuit current of the station auxiliary bus is controlled to be within 40kA, and the voltage drop of the bus is controlled to be within 5% of the nominal voltage. The station auxiliary bus sections of every two sets of energy storage systems are interconnected, and serve as standby power sources for each other, so that the reliability of power supply is improved.
[0028] The wiring structure of the application reduces the connection between the compressor energy storage condition and the energy releasing generation condition, effectively decouples the double conditions, and is high in flexibility and safety; each set of energy storage system adopts a modularized and redundant design, so that the reliability, independence and expandability of the compression system are improved; effective current limiting measures and interconnection structure are adopted, so that the cost of the station auxiliary equipment is effectively reduced, and the safety and reliability of the station auxiliary operation are improved.
Claims
1. A carbon dioxide energy storage power station system, characterized in that: The system includes a high-voltage power distribution device (1), an energy-releasing main transformer (2), an energy storage transformer (3), an energy-releasing generator (4), a circuit breaker, an energy storage system mainly including a compressor, and an energy-releasing system mainly composed of an energy-releasing generator (4) and an energy-releasing main transformer (2). The energy-releasing main transformer (2) and the energy storage transformer (3) are connected in parallel with the high-voltage power distribution device (1). The compressor includes a low-voltage compressor (5) and a high-voltage compressor (6). The low-voltage compressor (5) is connected to one of the output windings of the energy storage transformer (3) through a low-voltage compressor outlet circuit breaker (8). The high-voltage compressor (6) is connected to the other output winding of the energy storage transformer (3) through a high-voltage compressor outlet circuit breaker (12). The compressor is started by frequency conversion.
2. The power station system for carbon dioxide energy storage according to claim 1, characterized in that: The low-pressure compressor (5) and the high-pressure compressor (6) are started by the same set of variable frequency starter (14), which is connected in parallel with the high-pressure compressor (6) and the high-pressure compressor outlet circuit breaker (12) through the variable frequency starter outlet circuit breaker (13).
3. A carbon dioxide energy storage power station system according to claim 2, characterized in that: The high-voltage compressor and the output circuit breaker (9) of the variable frequency starter are also connected between the output circuit breaker (13) of the variable frequency starter, the output circuit breaker (12) of the high-voltage compressor, and one output winding of the energy storage transformer (3).
4. A carbon dioxide energy storage power station system according to any one of claims 1-3, characterized in that: The energy storage system is provided in at least two sets, and the energy storage transformer (3) of each set of energy storage system is connected in parallel to the high voltage power distribution device (1).
5. A carbon dioxide energy storage power station system according to claim 4, characterized in that: Each energy storage system’s energy storage transformer (3) is connected to the output winding of the high-voltage compressor (6) and a current-limiting reactor (7) is connected in parallel. The current-limiting reactors (7) of each energy storage system are also connected to each other through their respective plant branch circuit breakers (10) and the plant bus tie switch (11) of the energy storage system.
6. A carbon dioxide energy storage power station system according to claim 5, characterized in that: The frequency converter starting device (14) of each energy storage system is set up separately from other equipment of the energy storage system in different rooms.