阅读说明：本技术 基于10kV能量路由器重构的变电站用电源系统及控制方法 (Power supply system for transformer substation based on 10kV energy router reconstruction and control method ) 是由 金林 冷旭东 罗平东 刘之尧 于 2021-09-03 设计创作，主要内容包括：本发明公开了一种基于10kV能量路由器重构的变电站用电源系统,包括：能量路由器,所述能量路由器由双向AC/DC电子固态变压器、单向DC/DC光伏电池阵列接口电路和双向DC/DC储能电池阵列接口电路组成,所述双向AC/DC电子固态变压器的一端与电网接口连接,另一端与DC汇流母线连接,所述单向DC/DC光伏电池阵列接口电路和所述双向DC/DC储能电池阵列接口电路与DC汇流母线连接；柔性交流电源系统,所述柔性交流电源系统与所述能量路由器引出的DC汇流母线连接；柔性直流电源系统,所述柔性直流电源系统与所述能量路由器引出的DC汇流母线连接；柔性通讯电源系统,所述柔性通讯电源系统与所述能量路由器引出的DC汇流母线连接。解决了变电站大规模接入光伏、储能后,影响电网安全可靠性运行的问题,同时优化了站用电源系统设计。(The invention discloses a power supply system for a transformer substation based on 10kV energy router reconstruction, which comprises: the energy router consists of a bidirectional AC/DC electronic solid-state transformer, a unidirectional DC/DC photovoltaic cell array interface circuit and a bidirectional DC/DC energy storage cell array interface circuit, wherein one end of the bidirectional AC/DC electronic solid-state transformer is connected with a power grid interface, the other end of the bidirectional AC/DC electronic solid-state transformer is connected with a DC bus bar, and the unidirectional DC/DC photovoltaic cell array interface circuit and the bidirectional DC/DC energy storage cell array interface circuit are connected with the DC bus bar; the flexible alternating current power supply system is connected with a DC bus bar led out from the energy router; the flexible direct-current power supply system is connected with a DC bus bar led out from the energy router; and the flexible communication power supply system is connected with the DC bus bar led out by the energy router. The problem of the transformer substation influence the safe and reliable operation of the power grid after large-scale photovoltaic and energy storage access is solved, and the design of a power system for the substation is optimized.)

1. A power supply system for a transformer substation based on 10kV energy router reconfiguration is characterized by comprising:

the energy router consists of a bidirectional AC/DC electronic solid-state transformer, a unidirectional DC/DC photovoltaic cell array interface circuit and a bidirectional DC/DC energy storage cell array interface circuit, wherein one end of the bidirectional AC/DC electronic solid-state transformer is connected with a power grid interface, the other end of the bidirectional AC/DC electronic solid-state transformer is connected with a DC bus bar, and the unidirectional DC/DC photovoltaic cell array interface circuit and the bidirectional DC/DC energy storage cell array interface circuit are connected with the DC bus bar;

the flexible alternating current power supply system is connected with a DC bus bar led out from the energy router;

the flexible direct-current power supply system is connected with a DC bus bar led out from the energy router;

and the flexible communication power supply system is connected with the DC bus bar led out by the energy router.

2. The substation power supply system based on 10kV energy router reconfiguration according to claim 1, wherein said unidirectional DC/DC photovoltaic cell array interface circuit is composed of a first unidirectional DC/DC conversion module, an output end of said first unidirectional DC/DC conversion module is connected with a DC bus bar, an input end of said first unidirectional DC/DC conversion module is connected with an output end of a photovoltaic array, and said first unidirectional DC/DC conversion module and said photovoltaic array constitute a flexible photovoltaic system.

3. The power supply system for the transformer substation based on 10kV energy router reconfiguration according to claim 1, wherein the bidirectional DC/DC energy storage battery array interface circuit is composed of bidirectional DC/DC conversion modules, one ends of the bidirectional DC/DC conversion modules are connected with a DC bus bar, the other ends of the bidirectional DC/DC conversion modules are connected with an energy storage battery array, and the bidirectional DC/DC conversion modules and the energy storage battery array form a set of flexible energy storage system.

4. The substation power supply system based on 10kV energy router reconfiguration according to claim 3, characterized in that said flexible energy storage systems are at least two groups.

5. The substation power supply system based on 10kV energy router reconfiguration according to claim 1, characterized in that said flexible AC power supply system comprises a DC/AC conversion module, the input end of said DC/AC conversion module is connected with a DC bus bar, and the output end of said DC/AC conversion module is connected with an AC power load.

6. The substation power supply system based on 10kV energy router reconfiguration according to claim 1, characterized in that said flexible DC power supply system comprises a second unidirectional DC/DC conversion module, the input end of said second unidirectional DC/DC conversion module is connected with a DC bus bar, and the output end of said second unidirectional DC/DC conversion module is connected with a DC power supply load.

7. The substation power supply system based on 10kV energy router reconfiguration according to claim 1, characterized in that, the flexible communication power supply system comprises a third unidirectional DC/DC conversion module, an input end of the third unidirectional DC/DC conversion module is connected with a DC bus bar, and an output end of the third unidirectional DC/DC conversion module is connected with a DC communication power load.

8. The substation power supply system based on 10kV energy router reconfiguration according to claim 1, characterized in that said energy router is a multiport 10kV energy router and said bidirectional AC/DC electronic solid state transformer is a 10kV bidirectional AC/DC electronic solid state transformer.

Technical Field

The invention relates to the technical field of power supplies for flexible stations, in particular to a power supply system for a transformer substation based on 10kV energy router reconstruction and a control method.

Background

The existing substation power supply is mainly provided with a substation alternating current power supply subsystem for AC380V through voltage reduction of a 10kV transformer, the substation alternating current power supply AC/DC is rectified into DC220V/DC110V, a storage battery is used as a standby power supply to form the substation direct current power supply subsystem, an AC normal power supply and storage battery backup UPS sub-power supply system is used for supplying power, and the substation alternating current power supply AC/DC is rectified into DC48V and the storage battery is used as the standby power supply to form the substation direct current communication power supply subsystem. The station power supply system does not generally comprise a photovoltaic system and an energy storage system, a storage battery serving as a standby power supply is in a floating charging state for a long time when in normal operation, and regulations require that the storage battery cannot be separated from a direct current bus. The power architecture for a conventional substation is shown in fig. 3.

In 9/22/2020, the Chinese government announced more powerful policies and measures, and carbon emission of carbon dioxide was strived to reach a peak value by 2030 and strived to achieve "carbon neutralization" by 2060. The grid company is the prime force for carbon neutralization. According to the methods for accounting greenhouse gas emissions and the report guidelines (trial) of Chinese power grid enterprises issued and implemented in 2013, greenhouse gas emissions of power grid enterprises are mainly from: the emission generated in the repair and retirement process of SF6 equipment; and carbon dioxide generated in the power production link corresponding to the power transmission and distribution loss is discharged. At present, power grid companies gradually build SF6 recovery and treatment centers in various provinces, and 100% recovery treatment is basically realized. The emission is mainly carbon dioxide emission corresponding to power transmission and distribution loss, and the calculation formula is as follows:

the carbon dioxide emission (tCO2) caused by line loss is line loss electricity (MWh) multiplied by annual average power supply emission factor (tCO2/MWh) of the regional power grid.

Grid companies can achieve the goal of carbon reduction by reducing line losses, reducing power supply emission factors.

The number of transformer substations of a power grid company is large, photovoltaic cell panels are installed on roofs, enclosing walls and the like of the transformer substations, and container type energy storage systems deployed in the idle spaces are all good modes for the transformer substations to develop new energy and reduce carbon emission factors. The transformer substation becomes a main battlefield for realizing carbon reduction of a power grid company

The conventional station of transformer substation uses power supply system by 10kV conventional electromagnetic induction formula transformer, interchange switched systems, station with alternating current power supply system, station with direct current power supply system, station with UPS power supply system, station with communication power supply system, monitored control system etc. constitute, its framework is as attached figure 3, the characteristic is: 1. the conventional station power supply system does not contain a photovoltaic, energy storage and other distributed power supply systems. 2. The power supply for the conventional station is a unidirectional power supply, and electric energy cannot be reversely fed back to a power grid. 3. The flexible control is a technology for quickly and accurately controlling each link of electric energy based on a power electronic technology. A conventional 10kV transformer is a transformer based on an electromagnetic induction principle and does not have the capabilities of bidirectional electric energy control and electric energy quality regulation. 4. The station alternating current power supply system does not have a flexible control function; a storage battery pack in a station direct current power supply system is directly hung on a direct current bus, and under the condition that an alternating current power supply loses power, the storage battery pack is directly discharged under load without control, and does not have a flexible control function. 5. One of the measures for improving the reliability of the AC power supply system for the station is to adopt two paths of AC incoming line power supplies for switching. 6. The battery pack is used as a backup power supply of a station direct-current power supply system, a station UPS power supply system and a station communication power supply system, and has the disadvantages of large maintenance workload, easy failure and the like.

There are generally two conventional schemes for connecting a transformer substation to photovoltaic and energy storage: (1) the photovoltaic power is converted through the photovoltaic power inverter and stored energy through the alternating current AC380V power bus for the PCS access station; (2) photovoltaic inversion and energy storage PCS are connected to a 10kV bus through a single 10kV conventional transformer.

However, the above-described scheme has the following problems:

problem 1: if the photovoltaic energy storage is constructed in a large scale in a transformer substation, because the conventional transformer does not have the function of controlling the tide, a large amount of photovoltaic and energy storage of the transformer substation become uncontrollable power sources of a power grid and become unknown factors influencing the safe operation of the power grid.

Problem 2: if the photovoltaic energy storage station AC power supply access scheme is adopted, the safety and reliability of the station AC power supply are affected due to the instability or failure of the new energy trend; if the scheme that photovoltaic energy storage is connected into a 10kV bus through a special transformer is adopted, although interference on a station power supply is avoided, the problem 1 still exists, and meanwhile, the design of the existing station power supply is not optimized, and the scheme is still an imperfect scheme.

Disclosure of Invention

The invention mainly aims to provide a power supply system for a transformer substation based on 10kV energy router reconstruction, which can effectively solve the problems in the background technology.

In order to achieve the purpose, the invention adopts the technical scheme that:

a power supply system for a transformer substation based on 10kV energy router reconfiguration includes:

the energy router consists of a bidirectional AC/DC electronic solid-state transformer, a unidirectional DC/DC photovoltaic cell array interface circuit and a bidirectional DC/DC energy storage cell array interface circuit, wherein one end of the bidirectional AC/DC electronic solid-state transformer is connected with a power grid interface, the other end of the bidirectional AC/DC electronic solid-state transformer is connected with a DC bus bar, and the unidirectional DC/DC photovoltaic cell array interface circuit and the bidirectional DC/DC energy storage cell array interface circuit are connected with the DC bus bar;

the flexible alternating current power supply system is connected with a DC bus bar led out from the energy router;

the flexible direct-current power supply system is connected with a DC bus bar led out from the energy router;

and the flexible communication power supply system is connected with the DC bus bar led out by the energy router.

Furthermore, the unidirectional DC/DC photovoltaic cell array interface circuit is composed of a first unidirectional DC/DC conversion module, an output end of the first unidirectional DC/DC conversion module is connected with the DC bus bar, an input end of the first unidirectional DC/DC conversion module is connected with an output end of the photovoltaic array, and the first unidirectional DC/DC conversion module and the photovoltaic array form a flexible photovoltaic system.

Furthermore, the bidirectional DC/DC energy storage battery array interface circuit is composed of a bidirectional DC/DC conversion module, one end of the bidirectional DC/DC conversion module is connected with the DC bus bar, the other end of the bidirectional DC/DC conversion module is connected with the energy storage battery array, and the bidirectional DC/DC conversion module and the energy storage battery array form a group of flexible energy storage system.

Further, the flexible energy storage systems are at least two groups.

Further, the flexible alternating current power supply system comprises a DC/AC conversion module, wherein the input end of the DC/AC conversion module is connected with the DC bus bar, and the output end of the DC/AC conversion module is connected with an alternating current power supply load.

Further, the flexible direct current power supply system comprises a second unidirectional DC/DC conversion module, wherein the input end of the second unidirectional DC/DC conversion module is connected with the DC bus bar, and the output end of the second unidirectional DC/DC conversion module is connected with the direct current power supply load.

Furthermore, the flexible communication power supply system comprises a third unidirectional DC/DC conversion module, wherein the input end of the third unidirectional DC/DC conversion module is connected with the DC bus bar, and the output end of the third unidirectional DC/DC conversion module is connected with the DC communication power supply load.

Further, the energy router is a multi-port 10KV energy router, and the bidirectional AC/DC electronic solid-state transformer is a 10KV bidirectional AC/DC electronic solid-state transformer.

The power supply control method for the transformer substation based on 10kV energy router reconstruction of the power supply system for the transformer substation based on 10kV energy router reconstruction comprises the following steps:

the flexible photovoltaic system is enabled to preferentially supply power loads for the station, and when the flexible photovoltaic system meets the power loads for the station, the redundant part of electric energy charges the energy storage battery;

one group of flexible energy storage systems is in a standby power supply operation state, the other group of flexible energy storage systems is in an energy storage system charge-discharge operation state, and the two groups of flexible energy storage systems alternately work;

the flexible energy storage system is discharged to supply power load for the station preferentially, and redundant electric energy is fed back to the power grid under the control of the 10KV bidirectional AC/DC electronic solid-state transformer.

Further, the method also comprises the following steps:

when the 10kV alternating current is in power failure, the flexible photovoltaic system and the flexible energy storage system are used as a standby power supply of a station power supply to supply power for a station power supply load, and the emergency power supply requirements of different loads are met by cutting off the load in a time-sharing mode.

Compared with the prior art, the invention has the following beneficial effects:

the 10kV bidirectional AC/DC electronic solid-state transformer replaces a 10kV conventional electromagnetic induction type transformer, a photovoltaic system and an energy storage system become standard configurations, the energy storage system becomes a standby power supply of the whole system, a conventional direct-current power supply storage battery pack, a UPS power supply storage battery pack and a communication power supply storage battery pack are cancelled, and an alternating-current power supply system for a flexible station obtained by unidirectional DC/AC conversion replaces an alternating-current power supply system for a conventional station and the UPS power supply system;

the power supply system for the flexible station takes a power electronic conversion technology as a core, high-frequency transformers are isolated between the input and the output of all power conversion modules, and all subsystems have a flexible control function;

the photovoltaic and energy storage are connected to a power grid through a 10kV electronic solid-state transformer, the tidal current direction and the electric energy quality are controllable, the 10kV flexible solid-state transformer, a flexible photovoltaic system and a flexible energy storage system form a whole and are controlled by the power grid dispatching, a station power supply system becomes a bidirectional controllable power supply, and the station power supply not only takes power from the power grid, but also feeds power to the power grid, so that the station power supply becomes an important ring of an energy internet;

the flexible energy storage system is provided with two groups, one group is in a standby power supply operation state, and the other group is used for charging and discharging the energy storage system. The two groups of energy storage systems alternately work;

the system is in modular redundancy design, so that high reliability is provided;

various power electronic conversion functions are formed by sub power supply units which are connected in parallel and have redundancy, the system operation cannot be influenced by the faults of a few sub power supply units, particularly, the flexible solid-state transformer of 10kV which is used for total station bidirectional energy control and the flexible energy storage system which bears the carbon reduction task and a backup power supply cannot influence the safety and reliability of the system due to the faults of a few modules or storage batteries;

drawings

Fig. 1 is a schematic diagram of a system structure of a substation power supply system based on 10kV energy router reconfiguration.

Fig. 2 is a 10kV energy router schematic block diagram of a substation power supply system reconstructed based on a 10kV energy router according to the present invention.

Fig. 3 is a diagram of a conventional power supply architecture for a station.

In the figure: 10. a 10KV bidirectional AC/DC electronic solid-state transformer; 20. a first unidirectional DC/DC conversion module; 30. a bidirectional DC/DC conversion module; 40. a DC/AC conversion module; 50. a second unidirectional DC/DC conversion module; 60. a third unidirectional DC/DC conversion module; 70. a photovoltaic array; 80. an array of energy storage cells.

Detailed Description

In order to make the technical means, the creation characteristics, the achievement purposes and the effects of the invention easy to understand, the invention is further described with the specific embodiments.

As shown in fig. 1-2, a power supply system for a transformer substation based on 10kV energy router reconfiguration includes:

the energy router consists of a bidirectional AC/DC electronic solid-state transformer, a unidirectional DC/DC photovoltaic cell array interface circuit and a bidirectional DC/DC energy storage cell array interface circuit, wherein one end of the bidirectional AC/DC electronic solid-state transformer is connected with a power grid interface, the other end of the bidirectional AC/DC electronic solid-state transformer is connected with a DC bus bar, and the unidirectional DC/DC photovoltaic cell array interface circuit and the bidirectional DC/DC energy storage cell array interface circuit are connected with the DC bus bar;

the flexible alternating current power supply system is connected with a DC bus bar led out from the energy router;

the flexible direct-current power supply system is connected with a DC bus bar led out from the energy router;

and the flexible communication power supply system is connected with the DC bus bar led out by the energy router.

The unidirectional DC/DC photovoltaic cell array interface circuit is composed of a first unidirectional DC/DC conversion module 20, an output end of the first unidirectional DC/DC conversion module 20 is connected with a DC bus bar, an input end of the first unidirectional DC/DC conversion module 20 is connected with an output end of a photovoltaic array 70, and the first unidirectional DC/DC conversion module 20 and the photovoltaic array 70 form a flexible photovoltaic system.

The bidirectional DC/DC energy storage battery array interface circuit is composed of a bidirectional DC/DC conversion module 30, one end of the bidirectional DC/DC conversion module 30 is connected with a DC bus bar, the other end of the bidirectional DC/DC conversion module 30 is connected with an energy storage battery array 80, and the bidirectional DC/DC conversion module 30 and the energy storage battery array 80 form a flexible energy storage system.

Wherein, the flexible energy storage system is at least two groups.

The flexible alternating current power supply system comprises a DC/AC conversion module 40, wherein the input end of the DC/AC conversion module 40 is connected with a DC bus bar, and the output end of the DC/AC conversion module 40 is connected with an alternating current power supply load.

The flexible direct current power supply system comprises a second unidirectional DC/DC conversion module 50, wherein the input end of the second unidirectional DC/DC conversion module 50 is connected with the DC bus bar, and the output end of the second unidirectional DC/DC conversion module 50 is connected with the direct current power supply load.

The flexible communication power supply system comprises a third unidirectional DC/DC conversion module 60, wherein the input end of the third unidirectional DC/DC conversion module 60 is connected with the DC bus bar, and the output end of the third unidirectional DC/DC conversion module 60 is connected with the DC communication power supply load.

The energy router is a multi-port 10KV energy router, and the bidirectional AC/DC electronic solid-state transformer is a 10KV bidirectional AC/DC electronic solid-state transformer 10.

The power supply control method for the transformer substation based on 10kV energy router reconstruction of the power supply system for the transformer substation based on 10kV energy router reconstruction comprises the following steps:

the flexible photovoltaic system is enabled to preferentially supply power loads for the station, and when the flexible photovoltaic system meets the power loads for the station, the redundant part of electric energy charges the energy storage battery;

one group of flexible energy storage systems is in a standby power supply operation state, the other group of flexible energy storage systems is in an energy storage system charge-discharge operation state, and the two groups of flexible energy storage systems alternately work;

the flexible energy storage system is discharged to supply power load for the station preferentially, and redundant electric energy is fed back to the power grid under the control of the 10KV bidirectional AC/DC electronic solid-state transformer.

Wherein, still include the following step:

when the 10kV alternating current is in power failure, the flexible photovoltaic system and the flexible energy storage system are used as a standby power supply of a station power supply to supply power for a station power supply load, and the emergency power supply requirements of different loads are met by cutting off the load in a time-sharing mode.

In the embodiment, the photovoltaic and the stored energy are connected into a power grid through a 10kV electronic solid-state transformer; the sub-systems of the power supply for the station can be isolated from each other, photovoltaic and energy storage of the power supply for the station are accessed, and meanwhile, the power supply system becomes a standby power supply system of the sub-systems of the power supply for the station. The two problems mentioned in the background art are solved, the design of the existing power supply for the station is optimized, and the effect of '1 +1> 2' is achieved, specifically:

the multi-port 10kV energy router is composed of a 10kV bidirectional AC/DC electronic solid-state transformer, a unidirectional DC/DC photovoltaic battery array interface circuit and a bidirectional DC/DC energy storage battery array interface circuit.

A power supply system for a flexible station is constructed by taking a multi-port 10kV energy router as a core. The power supply system for the flexible station comprises a 10kV electronic solid-state transformer, a flexible photovoltaic system, a flexible energy storage system, a flexible alternating current power supply system, a flexible direct current power supply system, a flexible communication power supply system, a monitoring system and the like.

Compared with the conventional power system architecture for the station, the power system architecture for the station has the main differences that:

1. the conventional power supply system for the station uses a 10kV conventional electromagnetic induction type transformer, and does not have bidirectional electric energy control capability and electric energy quality regulation capability, and the 10kV bidirectional AC/DC electronic solid-state transformer is adopted to replace the 10kV conventional electromagnetic induction type transformer, so that the system can feed back the electric energy of the energy storage system to the power grid, and has bidirectional electric energy control capability and controllable electric energy quality.

2. Firstly, the conventional electromagnetic induction type transformer does not have a tidal current control function, so that the constructed photovoltaic energy storage system of the transformer substation becomes an uncontrollable power supply of a power grid and becomes a potential safety hazard of the operation of the power grid; secondly, if the photovoltaic energy storage station uses an alternating current power supply access scheme, the instability or the fault of a new energy trend can affect the safety and the reliability of the station alternating current power supply; thirdly, if the photovoltaic energy storage uses a scheme that a special transformer is connected to a 10kV bus, although no interference is generated on the station power supply, the first problem still exists, and the design of the existing station power supply is not optimized. According to the photovoltaic energy storage system, the photovoltaic energy storage system is connected into a power grid through the 10kV electronic solid-state transformer, and the power flow direction and the power quality are controllable. The 10kV flexible solid-state transformer, the flexible photovoltaic system and the flexible energy storage system form a whole, the control from power grid dispatching is received, the station power supply system becomes a bidirectional controllable power supply, in addition, each subsystem of the station power supply can be isolated from each other, photovoltaic and energy storage of the station power supply are accessed, and meanwhile, the station power supply system becomes a standby power supply system of each subsystem of the station power supply, so that the photovoltaic system and the energy storage system become standard configuration;

3. direct current power supply storage battery, UPS power supply storage battery, the communication power supply storage battery that conventional station used the power are difficult to maintain, easy trouble, and energy storage system becomes entire system's stand-by power supply in this application, and other subsystems do not dispose the back-up power supply system, and the maintenance work volume reduces greatly.

4. According to the flexible station AC power supply system, the AC power supply system for the flexible station obtained by unidirectional DC/AC conversion is used for replacing a conventional AC power supply system for the station and a UPS power supply system.

The power supply system for the flexible station takes a power electronic conversion technology as a core, the input and the output of all power conversion modules are isolated by high-frequency transformers, and all subsystems have a flexible control function.

Photovoltaic and energy storage are connected to a power grid through a 10kV electronic solid-state transformer. The 10kV flexible solid-state transformer, the flexible photovoltaic system and the flexible energy storage system form a whole and are controlled by power grid dispatching. The station power system becomes a bidirectional controllable power source. The station power supply not only takes electricity from the power grid, but also feeds electricity to the power grid, and becomes an important ring of an energy internet.

The flexible energy storage system is configured with two groups: one group is in a standby power supply operation state; and one group is used for charging and discharging the energy storage system. The two groups of energy storage systems work alternately.

The system is in a modular redundant design, and high reliability is provided.

Various power electronic conversion functions are formed by the sub power supply units which are connected in parallel and redundant, and the system operation cannot be influenced by the faults of a few sub power supply units. Particularly, the flexible solid-state transformer of 10kV used as total station bidirectional energy control and the flexible energy storage system bearing the carbon reduction task and the backup power supply cannot influence the safety and reliability of the system due to the faults of a few modules or storage batteries.

The power system architecture for the flexible station is shown in the attached figure 3, the flexible photovoltaic system and the flexible energy storage system are used as standby power sources of power loads for other stations through a whole station direct current bus, and the standby power source system with the characteristic that a storage battery is not configured for other subsystems under the condition of alternating current power failure is omitted.

The normal operation mode of the system is as follows:

(1) when the photovoltaic is sufficient, the power supply station is preferentially supplied with power loads, and redundant parts charge the energy storage battery;

(2) the flexible energy storage system is configured with two groups: one group is in a standby power supply operation state; and one group is used for charging and discharging the energy storage system. The two groups of energy storage systems work alternately.

(3) The energy storage system can utilize the peak-to-valley time difference for charging and discharging. The energy storage system discharges power loads for the priority supply station, and redundant electric energy is fed back to the power grid under the control of the 10kV flexible solid-state transformer.

10kV alternating current power failure operation mode:

when the 10kV alternating current is in power failure, the flexible photovoltaic system and the flexible energy storage system are used as a standby power supply of the station power supply to supply power for the station power supply load. In order to ensure different discharging power supply time, the emergency power supply requirements of different loads can be ensured by adopting a strategy of cutting off the loads in a time-sharing manner.

By using the power supply system for the flexible station, the difficult problems of photovoltaic access and energy storage of a large-scale substation of a power grid are solved, and technical innovation is brought.

The power supply system for the flexible station not only achieves carbon neutralization to a power grid company and has important influence, but also plays a positive role in improving the safety of the power supply for the substation and changing the functions of the substation: the transformer substation is not only a center for distributing electric energy, but also a center for peak clipping and valley filling, and the stabilizer for optimizing the quality of the electric energy.

The foregoing shows and describes the general principles and broad features of the present invention and advantages thereof. It will be understood by those skilled in the art that the present invention is not limited to the embodiments described above, which are described in the specification and illustrated only to illustrate the principle of the present invention, but that various changes and modifications may be made therein without departing from the spirit and scope of the present invention, which fall within the scope of the invention as claimed. The scope of the invention is defined by the appended claims and equivalents thereof.