WO2024001681A1

WO2024001681A1 - Hybrid energy storage assisted thermal power frequency modulation system

Info

Publication number: WO2024001681A1
Application number: PCT/CN2023/098355
Authority: WO
Inventors: 林松青; 潘喜良; 戴海鹏; 杜武荣; 石敦义; 黄秀晶; 梁晓斌; 王冰礁; 张智远; 李�昊; 李腾旭; 詹修平; 杨沛豪; 兀鹏越; 寇水潮; 王小辉; 燕云飞; 郭昊; 殷悦; 李志鹏
Original assignee: 华能罗源发电有限责任公司; 西安热工研究院有限公司
Priority date: 2022-06-29
Filing date: 2023-06-05
Publication date: 2024-01-04
Also published as: CN218102597U

Abstract

A hybrid energy storage assisted thermal power frequency modulation system, comprising: a thermal power generation grid-connected unit, a startup/standby transformer standby energy storage unit, and a high voltage plant transformer conventional energy storage unit. A high voltage side of the thermal power generation grid-connected unit is connected to a high voltage side of the startup/standby transformer standby energy storage unit, and a low voltage side of the thermal power generation grid-connected unit is connected to a low voltage side of the startup/standby transformer standby energy storage unit and the high voltage plant transformer conventional energy storage unit.

Description

Hybrid energy storage auxiliary thermal power frequency regulation system

Cross-references to related applications

This application is filed based on a Chinese patent application with application number 202221657709.5 and a filing date of June 29, 2022, and claims the priority of the Chinese patent application. The entire content of the Chinese patent application is hereby incorporated into this application as a reference.

Technical field

The present disclosure relates to the field of power transmission technology, and in particular, to a hybrid energy storage-assisted thermal power frequency modulation system.

Background technique

With the increase in the amount of wind power and conventional energy storage connected to the grid, the rapid development of interconnected large power grids, large-capacity power generation and long-distance power transmission, the frequency regulation task of the power system has become more arduous. In related technologies, frequency modulated power supplies are mainly thermal power units and hydropower units. The working principle is to track the system frequency changes by adjusting the active power output of the unit. However, thermal power units usually have problems such as long response lag and low unit ramp rate. They cannot accurately track power grid dispatching instructions, exposing phenomena such as adjustment time delays, adjustment deviations, and adjustment reversals. In addition, the frequent power conversion operation of thermal power units will aggravate the fatigue and wear of the unit equipment and affect the operating life of the unit.

Contents of the invention

Embodiments of the present disclosure provide a hybrid energy storage-assisted thermal power frequency regulation system, including: a thermal power generation grid-connected unit, a backup energy storage unit for a start-up transformer, and a conventional energy storage unit for a high-power transformer;

Wherein, the high-voltage side of the thermal power generation grid-connected unit is connected to the high-voltage side of the start-up transformer backup energy storage unit, and the low-voltage side of the thermal power generation grid-connected unit is connected to the low voltage side of the start-up transformer backup energy storage unit. Side and the high factory transform into conventional energy storage units.

In one embodiment of the present disclosure, the thermal power generation grid-connected unit includes: a generator, a generator main transformer and a power grid transmission bus;

Wherein, the outlet of the generator is connected to the low-voltage side of the generator main transformer, and the high-voltage side of the generator main transformer is connected to the power grid transmission bus;

The outlet of the generator is the low-voltage side of the thermal power generation grid-connected unit, and the power grid transmission bus is the high-voltage side of the thermal power generation grid-connected unit.

In one embodiment of the present disclosure, the voltage level corresponding to the electric energy output by the generator is 20kV.

In one embodiment of the present disclosure, the voltage level of the power grid transmission bus is 220kV.

In one embodiment of the present disclosure, the backup energy storage unit of the startup transformer includes: the thermal power unit startup transformer, the low-voltage side A branch bus of the startup transformer, the low-voltage side B branch bus of the startup transformer, and the low-voltage side A branch bus of the startup transformer. Branch circuit breakers, backup energy storage step-up transformers, backup energy storage grid-connected circuit breakers, backup energy storage converters and backup energy storage equipment;

Wherein, the low-voltage side of the starter transformer of the thermal power unit is connected to the A branch bus of the low-voltage side of the starter transformer and the B branch bus of the low-voltage side of the starter transformer. The A branch bus of the low-voltage side of the starter transformer passes through the starter transformer. Standby transformer low-voltage side branch A circuit breaker Connected to the outlet of the generator, the low-voltage side B branch bus of the starter transformer is connected to the standby energy storage boost transformer, and the standby energy storage boost transformer is connected to the standby energy storage grid-connected circuit breaker. The AC side of the backup energy storage converter, and the DC side of the backup energy storage converter are connected to the backup energy storage device;

The high-voltage side of the startup transformer of the thermal power unit is the high-voltage side of the backup energy storage unit of the startup transformer, and one end of the low-voltage side A branch circuit breaker of the startup transformer connected to the outlet of the generator is the startup transformer. The low voltage side of the backup energy storage unit.

In one embodiment of the present disclosure, the high-voltage conventional energy storage unit includes: a split-winding high-voltage transformer, a 6kV factory A branch, a 6kV factory B branch, a 6kV factory A branch circuit breaker, a 6kV factory A branch Branch load, 6kV factory B branch circuit breaker, 6kV factory B branch load, conventional energy storage power electronic transformer PET grid-connected circuit breaker, PET, conventional energy storage PET low-voltage side circuit breaker, conventional energy storage inverter and conventional energy storage energy equipment;

Wherein, the high voltage side of the split winding high power transformer is connected to the outlet of the generator, and the low voltage side of the split winding high power transformer is connected to the 6kV power plant A branch and the 6kV power plant B branch, so The 6kV factory A branch is connected to the 6kV factory A branch load through the 6kV factory A branch circuit breaker, and the 6kV factory B branch is connected to the 6kV factory through the 6kV factory B branch circuit breaker. With B branch load, the high voltage side of the PET is connected to the 6kV factory B branch through the conventional energy storage PET grid-connected circuit breaker, and the low voltage side of the PET is connected through the conventional energy storage PET low voltage side circuit breaker. to the AC side of the conventional energy storage converter, and the DC side of the conventional energy storage converter is connected to the conventional energy storage device.

In one embodiment of the present disclosure, the PET includes: a conventional energy storage PET high-voltage DC-DC converter, a conventional energy storage PET high-voltage side filter capacitor, a conventional energy storage PET high-frequency DC-DC DC-DC transformer, a conventional energy storage PET Energy-saving PET low-voltage side filter capacitors and conventional energy-storage PET low-voltage AC-DC converters;

Wherein, the AC side of the conventional energy storage PET high-voltage DC-DC converter is connected to the conventional energy storage PET grid-connected circuit breaker, and the high voltage side of the conventional energy storage PET high-frequency DC-DC transformer passes through the conventional energy storage PET The energy-storage PET high-voltage side filter capacitor is connected to the DC side of the conventional energy-storage PET high-voltage DC-DC converter, and the DC side of the conventional energy-storage PET low-voltage AC-DC converter is filtered by the conventional energy-storage PET low-voltage side. The capacitor is connected to the low-voltage side of the conventional energy-storage PET high-frequency DC-DC transformer, and the AC side of the conventional energy-storage PET low-voltage AC-DC converter is connected to the conventional energy-storage PET low-voltage side circuit breaker.

In one embodiment of the present disclosure, the PET is composed of modular multi-level converter MMC power electronic components.

In summary, the embodiments of the present disclosure at least bring the following beneficial effects:

1. This disclosure can improve the response speed of the hybrid energy storage-assisted thermal power frequency regulation system when performing frequency regulation tasks by using a hybrid energy storage auxiliary thermal power frequency regulation system composed of a backup energy storage unit for a start-up transformer and a conventional energy storage unit for a high-power transformer. Increase the unit’s climbing rate.

2. This disclosure responds to grid load changes by utilizing the fast charging/discharging capabilities of backup energy storage equipment and conventional energy storage equipment. Whether it is primary frequency modulation, secondary frequency modulation or multiple frequency modulation, it can assist thermal power generation grid-connected units to perform optimal operations. Excellent power matching. Therefore, the frequency regulation revenue of thermal power plants can be increased, the output fluctuation of generators can be reduced, the safety of thermal power units can be improved, and the aging of thermal power unit equipment caused by frequent load adjustments can be reduced. It can reduce the number of power conversion operations; furthermore, it can reduce the fatigue and wear of thermal power unit equipment, and improve the operation of thermal power unit equipment. life.

3. By using PET, this disclosure can improve the conventional energy storage power supply efficiency of the conventional energy storage unit of the factory, and can save the energy storage system construction cost of the conventional energy storage unit of the factory. Moreover, by using PET, the present disclosure can improve the speed and accuracy of power changes in response to unit frequency adjustment.

4. The PET used in this disclosure adopts high-frequency electromagnetic coupling technology. On the basis of realizing the voltage level conversion, isolation and other functions of traditional transformers, it can also flexibly transform voltage, which can effectively reduce the area and volume of the transformer.

5. The PET used in this disclosure is composed of MMC power electronic components. MMC power electronic components have low output harmonics, high power conversion efficiency, and high scalability. The voltage conversion of the MMC power electronic component is controllable, which can effectively suppress the short-circuit current caused by ground faults and reduce the expansion of the fault scope during a fault.

Additional aspects and advantages of the disclosure will be set forth in part in the description which follows, and in part will be obvious from the description, or may be learned by practice of the disclosure.

Description of drawings

The above and/or additional aspects and advantages of the present disclosure will become apparent and readily understood from the following description of the embodiments in conjunction with the accompanying drawings, in which:

Figure 1 is a schematic structural diagram of a hybrid energy storage-assisted thermal power frequency regulation system provided by an embodiment of the present disclosure.

Explanation of reference symbols: 1—Thermal power generation grid-connected unit; 2—Start-up transformer backup energy storage unit; 3—High-power plant transformer conventional energy storage unit;

1-1—Generator; 1-2—Generator main transformer; 1-3—Power grid transmission busbar;

2-1—The thermal power unit’s starting transformer; 2-2—The A branch busbar on the low-voltage side of the Qibei transformer; 2-3—The B branch busbar on the low-voltage side of the Qibei transformer; 2-4—The branch A circuit breaker on the low-voltage side of the Qibei transformer; 2-5—Standby energy storage boost transformer; 2-6—Standby energy storage grid-connected circuit breaker; 2-7—Standby energy storage converter; 2-8—Standby energy storage equipment;

3-1—Split winding high factory transformer; 3-2—6kV factory A branch; 3-3—6kV factory B branch; 3-4—6kV factory A branch circuit breaker; 3-5—6kV factory A Branch load; 3-6—6kV factory B branch circuit breaker; 3-7—6kV factory B branch load; 3-8—conventional energy storage PET grid-connected circuit breaker; 3-9—conventional energy storage PET high-voltage direct- AC current converter; 3-10—conventional energy storage PET high-voltage side filter capacitor; 3-11—conventional energy storage PET high-frequency DC-DC transformer; 3-12—conventional energy storage PET low-voltage side filter capacitor; 3-13—conventional Energy storage PET low-voltage AC-DC converter; 3-14—Conventional energy storage PET low-voltage side circuit breaker; 3-15—Conventional energy storage converter; 3-16—Conventional energy storage equipment.

Detailed ways

Embodiments of the present disclosure are described in detail below, examples of which are illustrated in the accompanying drawings, wherein the same or similar reference numerals throughout represent the same or similar elements or elements having the same or similar functions. The embodiments described below with reference to the drawings are exemplary and are only used to explain the present disclosure and are not to be construed as limitations of the present disclosure. On the contrary, the disclosed embodiments include all changes, modifications and equivalents falling within the spirit and scope of the appended claims.

The present disclosure will be described in detail below with reference to specific embodiments.

As shown in Figure 1, an embodiment of the present disclosure provides a hybrid energy storage-assisted thermal power frequency regulation system, including: a thermal power generation grid-connected unit 1, a backup energy storage unit 2 for a start-up transformer, and a conventional energy storage unit 3 for a high-power transformer.

Among them, the high-voltage side of the thermal power generation grid-connected unit 1 is connected to the high-voltage side of the backup energy storage unit 2 of the start-up transformer, and the low-voltage side of the thermal power generation grid-connected unit 1 is connected to the low-voltage side and high-voltage side of the backup energy storage unit 2 of the start-up transformer. Energy storage unit 3.

According to some embodiments, hybrid energy storage technology is a large-scale energy storage technology that is one of the key technical supports for energy transformation. Because it can provide various auxiliary services such as peak shaving, frequency modulation, and emergency response for the power grid, it has received widespread attention in the industry in recent years. focus on.

In some embodiments, the backup energy storage unit 2 and the conventional energy storage unit 3 provided by the embodiments of the present disclosure may be a hybrid energy storage system composed of flywheel energy storage + lithium battery, respectively. Equipment 2-8 and conventional energy storage equipment 3-12 are connected to thermal power units through inverters and can have bidirectional power flow capabilities. Furthermore, it has the advantages of rapid power adjustment and diverse application modes.

In the embodiment of the present disclosure, the thermal power generation grid-connected unit 1 includes: a generator 1-1, a generator main transformer 1-2 and a power grid transmission bus 1-3.

Among them, the outlet of the generator 1-1 is connected to the low-voltage side of the generator main transformer 1-2, and the high-voltage side of the generator main transformer 1-2 is connected to the power grid transmission bus 1-3.

The outlet of the generator 1-1 is the low-voltage side of the thermal power generation grid-connected unit 1, and the grid transmission bus 1-3 is the high-voltage side of the thermal power generation grid-connected unit 1.

In the embodiment of the present disclosure, the voltage level corresponding to the electric energy output by the generator 1-1 is 20kV.

In the embodiment of the present disclosure, the voltage level of the power grid transmission buses 1-3 is 220kV.

According to some embodiments, the generator main transformer 1-2 can boost the electric energy output by the generator 1-1 from 20kV to 220kV.

In the embodiment of the present disclosure, the backup energy storage unit 2 of the start-up transformer includes: the start-up transformer 2-1 of the thermal power unit, the low-voltage side A branch bus of the start-up transformer 2-2, the low-voltage side B branch bus of the start-up transformer 2-3, Qibei transformer low-voltage side A branch circuit breaker 2-4, spare energy storage booster transformer 2-5, spare energy storage grid-connected circuit breaker 2-6, spare energy storage converter 2-7 and spare energy storage equipment 2- 8.

Among them, the low-voltage side of Qibei transformer 2-1 of the thermal power unit is connected to the A branch busbar 2-2 of the Qibei transformer low-voltage side and the B branch busbar 2-3 of the Qibei transformer low-voltage side. The A branch busbar 2-2 of the Qibei transformer low-voltage side It is connected to the outlet of the generator 1-1 through the A branch circuit breaker 2-4 on the low-voltage side of the Qibei substation. The B branch busbar 2-3 on the low-voltage side of the Qibei transformer is connected to the backup energy storage step-up transformer 2-5. The backup energy storage step-up transformer 2-5 The voltage transformer 2-5 is connected to the AC side of the backup energy storage converter 2-7 through the backup energy storage grid-connected circuit breaker 2-6, and the DC side of the backup energy storage converter 2-7 is connected to the backup energy storage device 2 -8.

The high-voltage side of the thermal power unit's backup transformer 2-1 is the high-voltage side of the backup energy storage unit 2 of the backup transformer. The low-voltage side branch A circuit breaker 2-4 of the backup transformer is connected to the outlet of the generator 1-1. The low voltage side of the backup energy storage unit 2.

According to some embodiments, when the thermal power plant is out of power for maintenance, the thermal power unit start-up transformer 2-1 can provide power for the thermal power plant.

In the embodiment of the present disclosure, the conventional energy storage unit 3 of the high power transformer includes: a split winding high power transformer 3-1, a 6kV power plant A branch 3-2, a 6kV power plant B branch 3-3, and a 6kV power plant A branch circuit breaker. 3-4, 6kV factory A branch load 3-5, 6kV factory B branch circuit breaker 3-6, 6kV factory B branch load 3-7, conventional energy storage power electronic transformer (Power Electronic Transformer, PET) and Network circuit breaker 3-8, PET, conventional energy storage PET low-voltage side circuit breaker 3-14, conventional energy storage inverter 3-15 and conventional energy storage equipment 3-16.

Among them, the high-voltage side of the split-winding high-voltage transformer 3-1 is connected to the outlet of the generator 1-1, and the low-voltage side of the split-winding high-voltage transformer 3-1 is connected to the 6kV factory A branch 3-2 and the 6kV factory B branch. 3-3, the 6kV factory A branch 3-2 is connected to the 6kV factory A branch load 3-5 through the 6kV factory A branch circuit breaker 3-4, and the 6kV factory B branch 3-3 is disconnected through the 6kV factory B branch The breaker 3-6 is connected to the 6kV factory B branch load 3-7. The high voltage side of the PET is connected to the 6kV factory B branch 3-3 through the conventional energy storage PET grid-connected circuit breaker 3-8. The low voltage side of the PET is connected to the 6kV factory B branch 3-3 through the conventional energy storage PET grid-connected circuit breaker 3-8. The energy PET low-voltage side circuit breaker 3-14 is connected to the AC side of the conventional energy storage converter 3-15, and the DC side of the conventional energy storage converter 3-15 is connected to the conventional energy storage device 3-16.

According to some embodiments, PET refers to a new type of power electronic equipment that is implemented through power electronics technology and high-frequency transformers (which operate at a higher frequency than power frequency transformers) and have but are not limited to the functions of traditional power frequency AC transformers. Compared with traditional power frequency transformers, the cost is lower, and PET is suitable for applications such as enriching system functions and improving system performance.

According to some embodiments, when controlling the energy storage converter, that is, the backup energy storage converter 2-7 and the conventional energy storage converter 3-15, a droop control method can be used to achieve active and reactive power solution. coupling control.

In the embodiment of the present disclosure, PET includes: conventional energy storage PET high-voltage DC-DC converter 3-9, conventional energy storage PET high-voltage side filter capacitor 3-10, conventional energy storage PET high-frequency DC-DC DC-DC transformer 3 -11. Conventional energy storage PET low-voltage side filter capacitor 3-12 and conventional energy storage PET low-voltage AC-DC converter 3-13.

Among them, the AC side of the conventional energy storage PET high-voltage DC-DC converter 3-9 is connected to the conventional energy storage PET grid-connected circuit breaker 3-8, and the high-voltage side of the conventional energy storage PET high-frequency DC-DC transformer 3-9 is connected to the conventional energy storage PET high-frequency DC-DC transformer 3-9. The energy storage PET high-voltage side filter capacitor 3-10 is connected to the DC side of the conventional energy storage PET high-voltage AC-DC converter 3-9, and the DC side of the conventional energy storage PET low-voltage AC-DC converter 3-13 passes through the conventional energy storage The PET low-voltage side filter capacitor 3-12 is connected to the low-voltage side of the conventional energy storage PET high-frequency DC-DC transformer 3-11, and the AC side of the conventional energy storage PET low-voltage AC-DC converter 3-13 is connected to the conventional energy storage PET Low voltage side circuit breaker 3-14.

In the embodiment of the present disclosure, PET is composed of modular multilevel converter (Modular Multilevel Converter, MMC) power electronic components.

According to some embodiments, MMC power electronic components refer to power electronic components composed of at least two sub-modules with the same structure cascaded. The structure of the sub-module includes but is not limited to half H-bridge type, full H-bridge type and double clamp sub-module type.

According to some embodiments, when the hybrid energy storage-assisted thermal power frequency regulation system provided by the embodiments of the present disclosure is working, if the hybrid energy storage-assisted thermal power frequency regulation system obtains a frequency regulation instruction for the thermal power generation grid-connected unit 1, then the hybrid energy storage-assisted thermal power frequency regulation system In response to the frequency modulation command, the high-power transformer can be controlled to transform into the conventional energy storage unit 3 and the start-up transformer into the backup energy storage unit 2 .

In some embodiments, when the hybrid energy storage-assisted thermal power frequency regulation system determines that the power signal corresponding to the frequency regulation command is less than the first power threshold, the hybrid energy storage-assisted thermal power frequency regulation system can respond to the frequency regulation command and control the high power plant to convert into a conventional energy storage unit. 3. Release energy to the thermal power generation grid-connected unit 1, or absorb the energy released by the thermal power generation grid-connected unit 1.

In some embodiments, when the hybrid energy storage-assisted thermal power frequency regulation system determines that the power signal corresponding to the frequency regulation command is greater than the second power threshold, the hybrid energy storage-assisted thermal power frequency regulation system can respond to the frequency regulation command and control the high power plant to change to conventional energy storage. The unit 3 and the backup energy storage unit 2 release energy to the thermal power generation grid-connected unit 1, or absorb the energy released by the thermal power generation grid-connected unit 1, and the second power threshold is not less than the first power threshold.

According to some embodiments, when the hybrid energy storage auxiliary thermal power frequency regulation system responds to the frequency regulation command, it controls the conventional energy storage unit 3 and the reserve energy storage unit 2 to release energy to the thermal power generation grid-connected unit 1, or absorb the thermal power generation. When the energy released by the grid-connected unit 1 is released, the hybrid energy storage auxiliary thermal power frequency regulation system can control the backup energy storage device 2-8 to be connected to the thermal power unit to start the backup transformer 2-1. Furthermore, the hybrid energy storage auxiliary thermal power frequency regulation system can control the backup energy storage device 2-8 and the conventional energy storage device 3-16 to jointly absorb energy or jointly release energy to respond to the frequency change corresponding to the frequency modulation command.

According to some embodiments, the frequency modulation instruction refers to an instruction for instructing to perform frequency modulation on the thermal power generation grid-connected unit 1 . This frequency modulation instruction does not refer to a fixed instruction. The frequency modulation instructions include but are not limited to frequency increase instructions, frequency decrease instructions, and so on.

In some embodiments, the frequency increase instruction, also known as the load increase instruction, refers to an instruction used to instruct to increase the frequency of the thermal power generation grid-connected unit 1 . If the frequency regulation command is a frequency increase command, the hybrid energy storage auxiliary thermal power frequency regulation system can control the backup energy storage device 2-8 and the conventional energy storage device 3-16 to release electric energy.

In some embodiments, the frequency reduction instruction, also known as the load reduction instruction, refers to an instruction for instructing to reduce the frequency of the thermal power generation grid-connected unit 1 . If the frequency regulation command is a frequency drop command, the hybrid energy storage auxiliary thermal power frequency regulation system can control the backup energy storage device 2-8 and the conventional energy storage device 3-16 to absorb electric energy.

In some embodiments, when the frequency regulation command is a frequency increase command, the hybrid energy storage auxiliary thermal power frequency regulation system can respond to the frequency increase command by controlling the high power supply to the conventional energy storage unit 3 and/or the start-up power supply to the backup energy storage unit 2. The thermal power generation grid-connected unit 1 releases energy.

In some embodiments, when the frequency regulation command is a frequency drop command, the hybrid energy storage auxiliary thermal power frequency regulation system can respond to the frequency drop command by controlling the high power supply to the conventional energy storage unit 3 and/or the start-up power supply to the backup energy storage unit 2 to absorb the energy. The energy released by thermal power generation grid-connected unit 1.

1. This disclosure can improve the response speed of the hybrid energy storage auxiliary thermal power frequency modulation system when performing frequency modulation tasks by using a hybrid energy storage-assisted thermal power frequency modulation system composed of a backup energy storage unit 2 and a conventional energy storage unit 3. , which can increase the unit’s climbing rate.

2. This disclosure adopts a hybrid energy storage auxiliary thermal power frequency regulation system composed of a backup energy storage unit 2 of a high-voltage transformer and a conventional energy storage unit 3 of a high-power transformer. This hybrid energy storage auxiliary thermal power frequency regulation system can be used to auxiliary thermal power generation grid-connected units. 1. Participate in power grid frequency mediation. Furthermore, the fast charging/discharging capabilities of the backup energy storage equipment 2-8 and the conventional energy storage equipment 3-16 can be used to respond to grid load changes, whether it is primary frequency modulation, secondary frequency modulation or multiple frequency modulation, to assist thermal power generation and Network unit 1 performs optimal power matching. Therefore, the frequency regulation revenue of the thermal power plant can be increased, the output fluctuation of the generator 1-1 can be reduced, the safety of the thermal power unit can be improved, and the aging of the thermal power unit equipment caused by frequent load adjustment can be reduced. It can reduce the number of power conversion operations; furthermore, it can reduce the fatigue and wear of thermal power unit equipment, and improve the operating life of thermal power unit equipment.

3. Since the backup energy storage equipment 2-8 passes through the backup energy storage converter 2-7, the backup energy storage grid-connected circuit breaker 2-6, the backup energy storage booster transformer 2-5 and the low-voltage side B branch bus of the Qibei transformer 2-3 is connected to the thermal power unit start-up transformer 2-1, and the conventional energy storage equipment 3-16 passes through the conventional energy storage inverter 3-15, conventional energy storage PET low-voltage side circuit breaker 3-14, PET, conventional energy storage PET Grid-connected circuit breaker 3-8 and 6kV factory B branch 3-3 are connected to the split winding high factory transformer 3-1, backup energy storage equipment 2-8 and conventional energy storage Devices 3-16 are connected to different transformers respectively. Therefore, the load factor of the split winding transformer 3-1 can be reduced, and the split winding transformer 3-1 can be ensured to operate with a certain margin, which can effectively reduce the load on the transformer without increasing the split winding transformer. The capacity of the transformer is 3-1 and the thermal power unit is ready to transform 2-1.

4. By using PET, this disclosure can improve the conventional energy storage power supply efficiency of the conventional energy storage unit 3 of the factory, and can save the energy storage system construction cost of the conventional energy storage unit 3 of the factory. Moreover, by using PET, the present disclosure can improve the speed and accuracy of power changes in response to unit frequency adjustment.

5. The PET used in this disclosure adopts high-frequency electromagnetic coupling technology. Compared with traditional power frequency transformers, on the basis of realizing the voltage level conversion, isolation and other functions of traditional transformers, it can also flexibly transform voltage, which can effectively reduce the size of the transformer. Ground area and volume.

6. The PET used in this disclosure is composed of MMC power electronic components. MMC power electronic components have low output harmonics, high power conversion efficiency, and high scalability. The voltage conversion of the MMC power electronic component is controllable, which can effectively suppress the short-circuit current caused by ground faults and reduce the expansion of the fault scope during a fault.

7. By controlling the conventional energy storage unit of the high-power transformer and the backup energy storage unit of the start-up transformer to perform actions corresponding to the power signal corresponding to the frequency modulation command, the present disclosure can accurately track the power grid dispatching command, reduce the adjustment delay time, and reduce the adjustment deviation. , Reduce adjustment reversal and other phenomena.

In the description of this specification, reference to the terms "one embodiment," "some embodiments," "an example," "specific examples," or "some examples" or the like means that specific features are described in connection with the embodiment or example. , structures, materials, or features are included in at least one embodiment or example of the present disclosure. In this specification, the schematic expressions of the above terms may be directed to different embodiments or examples. Furthermore, the specific features, structures, materials or characteristics described may be combined in any suitable manner in any one or more embodiments or examples. Furthermore, those skilled in the art may combine and combine different embodiments or examples and features of different embodiments or examples described in this specification unless they are inconsistent with each other.

In addition, the terms “first” and “second” are used for descriptive purposes only and cannot be understood as indicating or implying relative importance or implicitly indicating the quantity of indicated technical features. Therefore, features defined as "first" and "second" may explicitly or implicitly include at least one of these features. In the description of the present disclosure, "plurality" means at least two, such as two, three, etc., unless otherwise expressly and specifically limited.

In this disclosure, unless otherwise explicitly stated and limited, the terms "installation", "connection", "connection", "fixing" and other terms should be understood in a broad sense. For example, it can be a fixed connection or a detachable connection. , or integrated; it can be a mechanical connection or an electrical connection; it can be a direct connection or an indirect connection through an intermediate medium; it can be an internal connection between two elements or an interaction between two elements. For those of ordinary skill in the art, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

Although the embodiments of the present disclosure have been shown and described, those of ordinary skill in the art will appreciate that various changes, modifications, substitutions and variations can be made to these embodiments without departing from the principles and purposes of the disclosure. The scope of the disclosure is defined by the claims and their equivalents.

Claims

A hybrid energy storage auxiliary thermal power frequency regulation system, including: a thermal power generation grid-connected unit, a backup energy storage unit for a start-up transformer, and a conventional energy storage unit for a high-power transformer;

Wherein, the high-voltage side of the thermal power generation grid-connected unit is connected to the high-voltage side of the start-up transformer backup energy storage unit, and the low-voltage side of the thermal power generation grid-connected unit is connected to the low voltage side of the start-up transformer backup energy storage unit. Side and the high plant transform into conventional energy storage units.
The hybrid energy storage auxiliary thermal power frequency regulation system according to claim 1, wherein the thermal power generation grid-connected unit includes: a generator, a generator main transformer and a power grid transmission bus;

Wherein, the outlet of the generator is connected to the low-voltage side of the generator main transformer, and the high-voltage side of the generator main transformer is connected to the power grid transmission bus;

The outlet of the generator is the low-voltage side of the thermal power generation grid-connected unit, and the power grid transmission bus is the high-voltage side of the thermal power generation grid-connected unit.
The hybrid energy storage auxiliary thermal power frequency regulation system according to claim 2, wherein the voltage level corresponding to the electric energy output by the generator is 20kV.
The hybrid energy storage auxiliary thermal power frequency regulation system according to claim 2 or 3, wherein the voltage level of the power grid transmission bus is 220kV.
The hybrid energy storage auxiliary thermal power frequency regulation system according to any one of claims 2 to 4, wherein the backup energy storage unit for the startup transformer includes: the thermal power unit startup transformer, the startup transformer low-voltage side A branch bus, the startup transformer. The B branch busbar of the low-voltage side of the standby transformer, the branch A circuit breaker of the low-voltage side of the starting transformer, the standby energy storage booster transformer, the standby energy storage grid-connected circuit breaker, the standby energy storage converter and the standby energy storage equipment;

Wherein, the low-voltage side of the starter transformer of the thermal power unit is connected to the A branch bus of the low-voltage side of the starter transformer and the B branch bus of the low-voltage side of the starter transformer. The A branch bus of the low-voltage side of the starter transformer passes through the starter transformer. The A branch circuit breaker on the low-voltage side of the backup transformer is connected to the outlet of the generator, the B branch busbar on the low-voltage side of the backup transformer is connected to the backup energy storage boost transformer, and the backup energy storage boost transformer passes through the backup transformer. The energy storage grid-connected circuit breaker is connected to the AC side of the backup energy storage converter, and the DC side of the backup energy storage converter is connected to the backup energy storage device;

The high-voltage side of the startup transformer of the thermal power unit is the high-voltage side of the backup energy storage unit of the startup transformer, and one end of the low-voltage side A branch circuit breaker of the startup transformer connected to the outlet of the generator is the startup transformer. The low voltage side of the backup energy storage unit.
The hybrid energy storage auxiliary thermal power frequency modulation system according to any one of claims 2 to 5, wherein the high-voltage conventional energy storage unit includes: split winding high-voltage transformer, 6kV plant A branch, 6kV plant B Branch, 6kV factory A branch circuit breaker, 6kV factory A branch load, 6kV factory B branch circuit breaker, 6kV factory B branch load, conventional energy storage power electronic transformer PET grid-connected circuit breaker, PET, conventional energy storage PET Low-voltage side circuit breakers, conventional energy storage converters and conventional energy storage equipment;

Wherein, the high voltage side of the split winding high power transformer is connected to the outlet of the generator, and the low voltage side of the split winding high power transformer is connected to the 6kV power plant A branch and the 6kV power plant B branch, so The 6kV factory A branch is connected to the 6kV factory A branch load through the 6kV factory A branch circuit breaker, and the 6kV factory B branch is connected to the 6kV factory through the 6kV factory B branch circuit breaker. With B branch load, the high voltage side of the PET passes through the normal The conventional energy storage PET grid-connected circuit breaker is connected to the 6kV factory B branch, and the low voltage side of the PET is connected to the AC side of the conventional energy storage inverter through the conventional energy storage PET low voltage side circuit breaker. The DC side of the conventional energy storage converter is connected to the conventional energy storage device.
The hybrid energy storage auxiliary thermal power frequency modulation system as claimed in claim 6, wherein the PET includes: a conventional energy storage PET high-voltage DC converter, a conventional energy storage PET high-voltage side filter capacitor, a conventional energy storage PET high-frequency DC- DC DC-DC transformer, conventional energy storage PET low-voltage side filter capacitor and conventional energy storage PET low-voltage AC-DC converter;

Wherein, the AC side of the conventional energy storage PET high-voltage DC-DC converter is connected to the conventional energy storage PET grid-connected circuit breaker, and the high voltage side of the conventional energy storage PET high-frequency DC-DC transformer passes through the conventional energy storage PET The energy-storage PET high-voltage side filter capacitor is connected to the DC side of the conventional energy-storage PET high-voltage DC-DC converter, and the DC side of the conventional energy-storage PET low-voltage AC-DC converter is filtered by the conventional energy-storage PET low-voltage side. The capacitor is connected to the low-voltage side of the conventional energy-storage PET high-frequency DC-DC transformer, and the AC side of the conventional energy-storage PET low-voltage AC-DC converter is connected to the conventional energy-storage PET low-voltage side circuit breaker.
The hybrid energy storage auxiliary thermal power frequency regulation system according to claim 6, wherein the PET is composed of modular multi-level converter MMC power electronic components.