Energy storage system, power transmission system, control method, unit, and storage medium

Abstract

The embodiment of the invention provides an energy storage system, a power transmission system, a control method for black start of the power transmission system, an energy storage control unit and a storage medium, and relates to the technical field of power grid black start, and the energy storage system comprises an energy storage device and the energy storage control unit. The energy storage control unit is used for controlling the energy storage device to output electric energy according to the capacity information of the energy storage device and the power demand information of the power transmission system for black start under the condition that the power transmission system breaks down, and is used for providing start electric energy for black start for the power transmission system. According to the embodiment of the invention, the output electric energy of the energy storage device can be matched with the power demand of black start, the accuracy of controlling the output electric energy is improved, smooth completion of black start can be ensured, and the success rate and stability of the black start process are improved.

Description

Energy storage system, power transmission system, control method, unit and storage medium Technical Field

[0001] The present application relates to the technical field of power grid black start, and in particular to an energy storage system, a power transmission system, a control method for black start of a power transmission system, an energy storage control unit, and a storage medium. Background Art

[0002] A power grid black start refers to a situation where the entire power grid system stops operating due to a fault (isolated small power grids may still operate), and is in a completely "black" state. Without relying on the help of other systems, the power grid system starts up the generator sets with self-starting capabilities, which in turn drive the start-up of generator sets without self-starting capabilities, gradually expanding the scope of recovery of the power grid system and ultimately achieving the recovery of the entire power grid system. In related technologies, the black start of the power grid system is usually provided by hydropower units, wind turbines, and energy storage systems. However, hydropower units are unable to generate electricity during the dry season, wind turbines have problems with intermittent and fluctuating output power, and energy storage systems have insufficient capacity. Therefore, there is a problem that the power grid system cannot successfully complete the black start.

[0003] Summary of the Invention

[0004] The present disclosure provides an energy storage system, a power transmission system, a control method for a black start of a power transmission system, an energy storage control unit, and a storage medium, which can improve the success rate and stability of a black start process.

[0005] In a first aspect, the present disclosure provides an energy storage system, comprising: an energy storage device and an energy storage control unit; the energy storage control unit is configured to, in the event of a power transmission system failure, control the energy storage device to output electrical energy based on capacity information of the energy storage device and power requirement information of the power transmission system for a black start, thereby providing starting power for the power transmission system to perform a black start.

[0006] The energy storage system disclosed herein provides starting power for a black start through an energy storage device, thereby avoiding the self-excitation problem that occurs when a motor unit is used for a black start. The energy storage control unit matches the output power of the energy storage device with the power requirement for the black start based on the capacity information of the energy storage device and the power requirement for the black start, thereby ensuring the smooth completion of the black start and improving the success rate and stability of the black start process.

[0007] In some embodiments, the energy storage system includes: a first communication unit, through which the energy storage control unit establishes a communication connection with the dispatching system; the energy storage control unit is used to receive the power demand information sent by the dispatching system, and when it is determined that the capacity of the energy storage device meets the power demand of the black start, return an indication information confirming that the black start is met to the dispatching system; or, when it is determined that the capacity of the energy storage device does not meet the power demand of the black start, send the capacity information to the dispatching system; and control the energy storage device to output electric energy based on the power demand information or the first electric energy dispatching information returned by the dispatching system.

[0008] The energy storage control unit is connected to the dispatching system via a communication unit and can obtain comprehensive and accurate black start power demand information from the dispatching system. When it is determined that the capacity of the energy storage device can meet the total power required for the black start, the energy storage control unit controls the energy storage device to independently provide the starting power required for the black start. When it is determined that the capacity of the energy storage device does not meet the total power required for the black start, the dispatching system performs unified power coordination and scheduling. The energy storage control unit controls the energy storage device to output the starting power based on the power scheduling information returned by the dispatching system, and collaborates with other systems to complete the black start. This ensures the smooth completion of the black start regardless of whether the capacity of the energy storage device meets or does not meet the total power required for the black start, thereby improving the success rate and stability of the black start process.

[0009] In some embodiments, the energy storage system includes: a second communication unit; the energy storage control unit establishes a communication connection with the starting power control device through the second communication unit, and the energy storage control unit is used to control the energy storage device to output electric energy based on the power demand information when it is determined that the capacity of the energy storage device meets the power requirement of the black start; or, when it is determined that the capacity of the energy storage device does not meet the power requirement of the black start, send second electric energy scheduling information to the starting power control device, and control the energy storage device to output electric energy based on the power information and time that the energy storage device needs to output.

[0010] The energy storage control unit is connected to the starting power control device via a communication unit. When it is determined that the capacity of the energy storage device can meet the total power required for the black start, the energy storage control unit controls the energy storage device to independently provide the starting power required for the black start. When it is determined that the capacity of the energy storage device does not meet the total power required for the black start, the energy storage control unit performs unified power coordination and scheduling, and cooperates with other starting power devices to complete the black start. This ensures the smooth completion of the black start regardless of whether the capacity of the energy storage device meets or does not meet the total power required for the black start, thereby improving the success rate and stability of the black start process.

[0011] In some embodiments, the energy storage device includes: multiple energy storage module subunits, which are connected in series to form the energy storage device, and each energy storage subunit is respectively connected to the energy storage control unit; the energy storage control unit is used to obtain the remaining capacity of the energy storage subunit to determine the capacity information of the energy storage device; and control the energy storage subunit to output electrical energy.

[0012] The energy storage device adopts a modular multi-level cascade structure, which can improve the configuration capacity of the energy storage device; the energy storage control unit can obtain accurate capacity information of the energy storage device by detecting the capacity of each energy storage module sub-unit and independently controlling the output power of each energy storage module sub-unit. It can also provide a variety of power outputs for black start based on power demand, improving the control accuracy and precision of power output during the black start process, and ensuring the power demand and power supply of the black start process.

[0013] In some embodiments, the energy storage module subunit includes: a control subunit, a power unit and an energy storage unit; the energy storage unit includes an energy storage circuit formed by a battery pack and a pre-charging circuit connected in series; the energy storage circuit is connected in parallel with the first end of the corresponding power unit; the second end of each power unit is connected in series; the control subunit is respectively connected to the corresponding power unit, battery pack, pre-charging circuit, and is connected to the energy storage control unit, and is used to return the remaining capacity of the battery pack when receiving a capacity acquisition instruction sent by the energy storage control unit; and control the state of the power unit and control the on and off of the pre-charging circuit when receiving a control instruction sent by the energy storage control unit.

[0014] The energy storage module subunit uses a battery pack as its energy source. Through the charging and discharging functions of the battery pack, the energy storage module subunit can provide stable electric energy for a long time. The control subunit controls the power unit and pre-charge circuit to control the charging and discharging of the battery pack, which can improve the stability of the charging and discharging current of the battery pack. It has the advantages of good harmonic characteristics and low equivalent switching frequency, which can effectively prevent the battery pack from overcharging and over-discharging, making the charging and discharging of the battery pack safer and more reliable, and improving the service life of the battery pack. The pre-charge circuit can limit the peak current of the battery pack, play a protective role, reduce the impact current of the battery pack, improve the safety of the battery pack, and extend the service life of the battery pack.

[0015] In some embodiments, the energy storage system further includes: a current limiting circuit and an energy storage inductor; the current limiting circuit is arranged on the connection line between the first end or the second end of the energy storage device and the DC bus of the power transmission system; and / or the energy storage inductor is arranged on the connection line between the first end and / or the second end of the energy storage device and the DC bus of the power transmission system.

[0016] By connecting the energy storage device and the DC bus of the power transmission system through a current limiting circuit, an energy storage reactor, etc., the instantaneous impact current generated when the energy storage device and the DC bus are switched into grid connection can be reduced, thereby improving the safety of the energy storage system and extending the service life of the battery pack.

[0017] In some embodiments, the current limiting circuit includes: a starting resistor and a bypass switch connected in parallel with the starting resistor; the energy storage control unit is connected to the bypass switch to control the opening or closing of the bypass switch, so as to use the starting resistor for current limiting or short-circuiting the starting resistor.

[0018] By setting the starting resistor, the peak current of charging or discharging can be limited to play a protective role; the energy storage control unit closes the bypass switch when the energy storage device is in the charging and discharging working state to short-circuit the starting resistor and reduce the power consumed by the starting resistor.

[0019] In some embodiments, the energy storage system further includes a fault detection unit, which is arranged on the DC bus of the power transmission system and is configured to detect current data of the DC bus; and / or a DC control and protection unit, which is connected to the converter of the power transmission system and is used to obtain data of the converter and fault status information of the AC power grid of the power transmission system connected to the converter; the energy storage control unit is connected to the fault detection unit and / or the DC control and protection unit, and is used to determine whether a black start is required based on at least one of the current data, the converter data and the fault status information.

[0020] By detecting the current on the DC bus through the fault detection unit and obtaining the converter data and AC grid fault status information through the DC control and protection unit, the energy storage control unit can respond accurately and quickly when a grid fault occurs, thereby enhancing the sensitivity of the energy storage system, enabling rapid black start and troubleshooting, and improving the reliability of the transmission system.

[0021] A second aspect of the present disclosure provides a power transmission system, comprising the energy storage system provided by the first aspect of the present disclosure.

[0022] The power transmission system of the present disclosure has the advantages of the energy storage system of the present disclosure.

[0023] In some embodiments, the power transmission system includes: a DC bus, a converter and an AC power grid; the DC bus includes: a positive DC bus and a negative DC bus; both ends of the positive DC bus and the negative DC bus are respectively connected to the AC power grid through the converter.

[0024] By setting up an energy storage system on the DC side of the transmission system, the energy storage control unit selects the energy storage module sub-units to output electric energy to the DC bus based on the remaining capacity and power demand information or electric energy scheduling information, which can provide the transmission system with starting electric energy for black start; realizing a DC direct-connected energy storage method in the transmission system has the advantages of a high degree of modularity; it can improve the accuracy of controlling the output electric energy, effectively improve the regulation capability of the output electric energy, and improve the success rate and stability of the black start process.

[0025] A third aspect of the present disclosure provides a control method for a black start of a power transmission system, comprising: in the event of a failure in the power transmission system, obtaining capacity information of an energy storage device and power requirement information of the power transmission system for a black start; and controlling the energy storage device to output electric energy based on the capacity information and the power requirement information to provide starting electric energy for the black start to the power transmission system.

[0026] The control method for black start of a power transmission system disclosed in the present invention can match the output power of the energy storage device with the power demand of the black start, ensure the smooth completion of the black start, and improve the success rate and stability of the black start process.

[0027] In some embodiments, controlling the energy storage device to output electrical energy based on the capacity information and the power demand information to provide the power transmission system with starting electrical energy for a black start includes: when it is determined based on the capacity information and the power demand information that the capacity of the energy storage device meets the power demand for the black start, determining the power that the energy storage device needs to output according to the power demand information, so as to control the energy storage device to output electrical energy; or, when it is determined based on the capacity information and the power demand information that the capacity of the energy storage device does not meet the power demand for the black start, determining the power that the energy storage device needs to output and the startup time of the energy storage device according to at least one of the capacity information and the power demand information, so as to control the energy storage device to output electrical energy.

[0028] When the capacity of the energy storage device meets or does not meet the total power required for the black start, the power that the energy storage device needs to output or the power that the energy storage device needs to output and the startup time of the energy storage device are determined to control the energy storage device to output the starting power to complete the black start independently or in collaboration with other systems, thereby improving the success rate and stability of the black start process.

[0029] In some embodiments, obtaining the power requirement information of the transmission system for black start includes: receiving the power requirement information sent by the scheduling system; determining the power that the energy storage device needs to output based on the power requirement information includes: returning an indication information confirming that the black start is met to the scheduling system, and determining the power that the energy storage device needs to output based on the power requirement information; determining the power that the energy storage device needs to output and the start-up time of the energy storage device based on at least one of the capacity information and the power requirement information includes: sending the capacity information to the scheduling system and determining the power that the energy storage device needs to output and the start-up time of the energy storage device based on the first electric energy scheduling information returned by the scheduling system.

[0030] By obtaining power demand information from the dispatching system, comprehensive and accurate power demand information can be obtained. When the capacity of the energy storage device can meet the total power required for the black start, the energy storage device is controlled to independently provide the required power for the black start. When the capacity of the energy storage device does not meet the total power required for the black start, the dispatching system determines the power required to be output by the energy storage device and the start-up time of the energy storage device, and controls the energy storage device to coordinate with other systems to output the starting power to complete the black start. This can ensure the smooth completion of the black start regardless of whether the capacity of the energy storage device meets or does not meet the total power required for the black start, thereby improving the success rate and stability of the black start process.

[0031] In some embodiments, when the dispatching system determines, based on the received capacity information, that the capacity of the energy storage device does not meet the power requirement for a black start, the dispatching system determines, based on the capacity information, the power that the energy storage device needs to output; the dispatching system selects other starting power sources based on the power deviation between the power that the energy storage device needs to output and the power requirement for a black start, and determines the startup sequence of the energy storage device and the other starting power sources; the dispatching system sends the first electric energy dispatching information to the energy storage device; wherein, the information carried by the first electric energy dispatching information includes: the power that the energy storage device needs to output and startup time information.

[0032] Through unified power coordination and scheduling through the dispatching system, the starting power required by the energy storage device and the startup sequence are determined, so that the energy storage system and other systems can cooperate to complete the black start, which can ensure the smooth completion of the black start and improve the success rate and stability of the black start process.

[0033] In some embodiments, obtaining the power requirement information of the power transmission system for black start includes: obtaining the pre-configured power requirement information; determining the power that the energy storage device needs to output and the start-up time of the energy storage device based on at least one of the capacity information and the power requirement information includes: determining the power that the energy storage device needs to output and the supplementary power for black start based on the capacity information and the power requirement information; selecting a starting electric energy device based on the supplementary power and determining the start-up sequence and start-up time of the energy storage device and the selected starting electric energy device; sending second electric energy scheduling information to the starting electric energy control device; wherein, the information carried by the second electric energy scheduling information includes: the power that needs to be output and the start-up time information corresponding to the selected starting electric energy device; the starting electric energy control device controls the selected starting electric energy device to output electric energy based on the second electric energy scheduling information sent by the energy storage control unit.

[0034] Determining the startup sequence of the energy storage device and the selected startup electric energy device includes: determining the startup sequence based on power supply types of the energy storage device and the selected startup electric energy device and a startup sequence strategy corresponding to the power supply type.

[0035] If it is determined that the capacity of the energy storage device can meet the total power required for the black start, the energy storage control unit controls the energy storage device to independently provide the starting power required for the black start. If it is determined that the capacity of the energy storage device does not meet the total power required for the black start, the energy storage control unit performs unified power coordination and scheduling to determine the starting power required by itself and the energy storage device, as well as the starting sequence. This can ensure the smooth completion of the black start regardless of whether the capacity of the energy storage device meets or does not meet the total power required for the black start, thereby improving the success rate and stability of the black start process.

[0036] In some embodiments, the energy storage device includes a plurality of energy storage module subunits connected in series; the method further includes: obtaining the remaining capacity of each energy storage module subunit, and determining the capacity information based on the remaining capacity; and controlling the energy storage device to output electrical energy includes: selecting and controlling at least one energy storage module subunit from the plurality of energy storage module subunits to output electrical energy to the power transmission system.

[0037] By detecting the capacity of each energy storage module subunit of an energy storage device with a multi-level cascade structure and independently controlling the output power of each energy storage module subunit, accurate capacity information of the energy storage device can be obtained, and a variety of power outputs for black start can be provided based on power requirements, which can improve the accuracy and precision of power output control during the black start process.

[0038] In some embodiments, selecting and controlling at least one energy storage module subunit from the multiple energy storage module subunits to output electrical energy to the power transmission system includes: based on the remaining capacity and the power required to be output by the energy storage device, and using an SOC balancing control strategy to select and control the at least one energy storage module subunit to output a DC voltage.

[0039] Selecting the energy storage module subunits to output electrical energy based on the remaining capacity and the power required to be output by the energy storage device can improve the accuracy of controlling the output electrical energy, effectively improve the regulation capability of the output electrical energy, and improve the success rate and stability of the black start process; using the SOC balancing control strategy to control the DC bus voltage output by the energy storage module subunits can maintain the stability of the DC bus voltage, and can adjust the SOC convergence of the battery packs of each energy storage module subunit, better utilize the available capacity of the battery pack, improve the availability of the battery pack, make the electrical energy output by the energy storage module subunits more stable, and extend the service life of the battery pack.

[0040] In some embodiments, the use of the SOC balancing control strategy to select and control the output DC voltage of the at least one energy storage module subunit includes: sorting according to the SOC information of each energy storage module subunit to obtain an SOC sorting result; selecting the at least one energy storage module subunit according to the SOC sorting result; and performing PI control on the at least one energy storage module subunit based on a reference voltage and / or a reference current and the real-time voltage and / or real-time current of the at least one energy storage module subunit to output a DC bus voltage to the DC bus.

[0041] Based on the SOC balancing control strategy and according to the SOC sorting results, the energy storage module subunits are selected, and the PI control method is used to control the selected energy storage module subunits to output power to the DC bus. This can improve the accuracy of controlling the output power and enhance the success rate and stability of the black start process.

[0042] In some embodiments, the power transmission system includes a DC bus, a converter, and an AC power grid; the two ends of the DC bus are respectively connected to the AC power grid through the converter; before providing starting power for a black start to the power transmission system, the method further includes: determining whether the AC power grid needs to perform a black start.

[0043] By installing an energy storage system on the DC side of the transmission system and outputting electrical energy to the DC bus through the energy storage device, the transmission system can be provided with starting power for a black start. By determining whether a black start is required for the AC power grid, an accurate and rapid response can be made when a fault occurs, allowing for rapid troubleshooting.

[0044] In some embodiments, determining whether the AC power grid needs to be black-started includes: obtaining at least one of current data of the DC bus, data of the converter, and fault status information of the AC power grid to determine whether the AC power grid needs to be black-started.

[0045] Fault detection is performed based on the current data on the DC bus, the data of the converter, and the fault status information of the AC power grid. Accurate and rapid responses can be made to power grid faults, which enhances the sensitivity of the energy storage system, enables rapid black start and troubleshooting, and improves the reliability and management level of the power transmission system.

[0046] In some embodiments, when the power transmission system operates normally, the energy storage device is controlled to charge according to the capacity information.

[0047] By controlling the energy storage device to charge when it is suitable for charging, power conversion and energy storage can be achieved, ensuring that the energy storage device is fully charged, providing stable power, and ensuring the smooth completion of the black start process.

[0048] The fourth aspect of the present disclosure provides an energy storage control unit, comprising: a memory; and a processor coupled to the memory, the processor being configured to execute the control method for black start of a power transmission system provided in the third aspect of the present disclosure based on instructions stored in the memory.

[0049] The energy storage control unit disclosed in the present invention has the advantages of the control method for black start of a power transmission system disclosed in the present invention.

[0050] A fifth aspect of the present disclosure provides a computer-readable storage medium storing computer instructions, which are executed by a processor to provide a control method for black start of a power transmission system provided in the third aspect of the present disclosure. BRIEF DESCRIPTION OF THE DRAWINGS

[0051] In order to more clearly illustrate the technical solutions of the embodiments of the present application, the following is a brief introduction to the drawings required for use in the embodiments of the present application. Obviously, the drawings described below are only some embodiments of the present application. For ordinary technicians in this field, other drawings can be obtained based on the drawings without creative work.

[0052] FIG1 is a schematic diagram of a first system structure of some embodiments of the energy storage system disclosed in this application;

[0053] FIG2 is a schematic diagram of a second system structure of some embodiments of the energy storage system disclosed in this application;

[0054] FIG3 is a schematic diagram of a third system structure of some embodiments of the energy storage system disclosed in this application;

[0055] FIG4 is a schematic diagram of a fourth system structure of some embodiments of the energy storage system disclosed in this application;

[0056] FIG5 is a schematic diagram of a fifth system structure of some embodiments of the energy storage system disclosed in this application;

[0057] FIG6A is a sixth system structure diagram of some embodiments of the energy storage system disclosed in the present application; FIG6B is a first connection diagram of the control subunit in the energy storage module subunit and other units; FIG6C is a second connection diagram of the control subunit in the energy storage module subunit and other units;

[0058] FIG7 is a flow chart of some embodiments of a control method for black start of a power transmission system disclosed herein;

[0059] FIG8 is a schematic diagram of a flow chart of controlling the energy storage device to output electric energy in some embodiments of the control method for black start of a power transmission system disclosed herein;

[0060] FIG9 is a schematic diagram of a process of sending electric energy scheduling information by a scheduling system in some embodiments of the control method for black start of a power transmission system disclosed herein;

[0061] FIG10 is a schematic diagram of a flow chart of controlling the energy storage device to output electric energy in some embodiments of the control method for black start of a power transmission system disclosed herein;

[0062] FIG11 is a schematic diagram of a flow chart of electric energy output control in some embodiments of the control method for black start of a power transmission system disclosed herein;

[0063] FIG12 is a schematic diagram of modules in some embodiments of the energy storage control unit disclosed herein. DETAILED DESCRIPTION

[0064] The following detailed description of the embodiments of the present application is provided in conjunction with the accompanying drawings and examples. The following detailed description of the embodiments and the accompanying drawings are used to illustrate the principles of the present application, but are not intended to limit the scope of the present application, that is, the present application is not limited to the described embodiments.

[0065] In the description of the embodiments of the present application, the term "multiple" refers to more than two (including two). Similarly, "multiple groups" refers to more than two groups (including two groups), and "multiple pieces" refers to more than two pieces (including two pieces).

[0066] This application uses descriptions of directions or positional relationships such as "up", "down", "top", "bottom", "front", "back", "inside" and "outside" to facilitate the description of this application, and does not indicate or imply that the device referred to must have a specific direction, be constructed and operated in a specific direction. Therefore, it should not be understood as limiting the scope of protection of this application.

[0067] Furthermore, the terms "first," "second," and "third," etc., are used for descriptive purposes only and should not be construed as indicating or implying relative importance. "Perpendicular" does not strictly refer to perpendicularity, but rather to the tolerances allowed. "Parallel" does not strictly refer to parallelism, but rather to the tolerances allowed. The directional terms used in the following description refer to the directions shown in the figures and are not intended to limit the specific structure of this application.

[0068] It should also be noted that, in the description of this application, unless otherwise specified or limited, the terms "installed," "connected," and "connected" should be understood broadly. For example, they can refer to fixed connections, detachable connections, or integral connections; they can refer to direct connections or indirect connections through an intermediary. Those skilled in the art will understand the specific meanings of these terms in this application based on the specific circumstances.

[0069] In some embodiments, as shown in FIG1 , the present disclosure provides an energy storage system comprising an energy storage control unit 11 and an energy storage device 12. Energy storage device 12 can be a variety of energy storage devices and employ a variety of energy storage methods. For example, energy storage device 11 can include a battery pack, such as a lithium battery pack, which provides electrical energy. Providing starting power for a black start using energy storage device 12 can avoid the self-excitation problem that can occur when using a motor set for a black start.

[0070] The energy storage system may belong to the power transmission system 20 and serve as a subsystem of the power transmission system 20. The energy storage control unit 11 may obtain the capacity information of the energy storage device 12 and the power requirement information of the power transmission system 20 for a black start in a variety of ways. For example, a control subunit may be provided in the energy storage device 12, and the capacity information of the energy storage device 12 may be sent to the energy storage control unit 11 via the control subunit. Alternatively, a detection unit for detecting the capacity may be provided in the energy storage device 12, and the energy storage control unit 11 may obtain the capacity information of the energy storage device 12 detected by the detection unit. The power requirement information of the power transmission system 20 for a black start may be pre-stored in the energy storage control unit 11, or sent to the energy storage control unit 11 by other systems such as a dispatching system.

[0071] The energy storage control unit 11 can use various methods to determine whether the transmission system 20 has experienced a fault. For example, the energy storage control unit 11 can determine whether the transmission system 20 has experienced a fault by acquiring information collected by a detection device installed on the transmission system 20. Alternatively, the energy storage control unit 11 can determine whether the transmission system 20 has experienced a fault based on instructions sent by other systems, such as the dispatching system. In the event of a fault in the transmission system 20, the energy storage control unit 11 controls the energy storage device 12 to output electrical energy based on the capacity information of the energy storage device 12 and the power requirement information of the transmission system 20 for a black start, thereby providing the transmission system 20 with starting power for the black start. The power requirement information of the transmission system 20 for a black start includes the power output required by the starting power supply. The transmission system 20 can be a variety of systems, such as a flexible direct current transmission system. By controlling the output power of the energy storage device 12 based on the capacity information of the energy storage device and the power requirement information for a black start, the energy storage control unit 11 can accurately match the power requirement for the black start, ensuring the smooth completion of the black start and improving the success rate and stability of the black start process.

[0072] In some embodiments, as shown in FIG2 , the energy storage control unit 11 is communicatively connected to the dispatching system 30. The dispatching system 30 is an intelligent power grid dispatching automation system that can obtain and provide various real-time information required for the operation of the transmission system 20 (including power, bus voltage and other information), and control the operation of the transmission system 20 and perform dispatching decision management. The dispatching system 30 is an independent system relative to the transmission system 20. The dispatching system 30 can manage the transmission system 20 and perform operations such as power dispatching. It can be connected and communicated with the energy storage control unit 11 through an Ethernet network, a bus network, a wireless network, etc., and can perform data exchange. When a fault occurs in the transmission system 20, the dispatching system 30 determines the power demand information based on the network topology of the transmission system 20 and the power demand of the motor unit for black start, and can coordinate and control the starting power supply for the black start.

[0073] The energy storage system includes a first communication unit 60. The energy storage control unit 11 establishes a communication connection with the dispatching system 30 through the first communication unit 60 and exchanges data with the dispatching system 30 via an Ethernet network, a bus network, a wireless network, etc. The energy storage control unit 11 may also be provided with a communication interface for establishing a communication connection with the dispatching system 30.

[0074] The energy storage control unit 11 receives the power demand information sent by the dispatch system 20. If, based on the capacity information and power demand information of the energy storage device 12, it determines that the capacity of the energy storage device 12 can meet the power demand of the black start, it returns an indication to the dispatch system 30 confirming that the black start has been met. Based on the power demand information, the energy storage control unit 11 controls the energy storage device 12 to output electrical energy, independently providing the starting power for the black start. For example, if, based on the capacity of the energy storage device 12, the energy storage control unit 11 determines that the power output of the energy storage device 12 is greater than the power demand of the black start, it returns an indication to the dispatch system 30 confirming that the black start has been met.

[0075] If the energy storage control unit 11 determines that the capacity of the energy storage device 12 does not meet the power requirement for the black start, it sends the capacity information to the dispatching system 30 and controls the energy storage device to output electric energy based on the first electric energy dispatching information returned by the dispatching system 30. For example, if the energy storage control unit 11 determines based on the capacity of the energy storage device 12 that the electric energy power that the energy storage device 12 can output is less than or equal to the power requirement for the black start, it sends the capacity information of the energy storage device 12 to the dispatching system 30.

[0076] The dispatch system 30 prioritizes the startup capabilities of each system providing black start power and determines the startup time of each system. The systems collaborate to complete the startup and restoration of the power grid. The first power dispatch information includes the power output and startup time information required by the energy storage system of the present disclosure.

[0077] By communicating with the dispatching system 30 through the energy storage control unit 11, comprehensive and accurate power demand information can be obtained from the dispatching system 30. The energy storage control unit 11 switches the operating model of the energy storage device 12 to the black start mode. When it is determined that the capacity of the energy storage device 12 can meet the total power required for the black start, the energy storage control unit 11 controls the energy storage device 12 to independently provide the electric energy required for the black start; when it is determined that the capacity of the energy storage device 12 does not meet the total power required for the black start, the dispatching system 30 performs unified power coordination and scheduling. Based on the first electric energy dispatching information returned by the dispatching system 30, the energy storage control unit 11 controls the energy storage device 12 to output the starting electric energy, and cooperates with other systems to complete the black start. It can ensure the smooth completion of the black start whether the capacity of the energy storage device 12 meets or does not meet the total power required for the black start, thereby improving the success rate and stability of the black start process.

[0078] In some embodiments, as shown in FIG3 , the power transmission system includes a starting power control device 40 and a starting power device 50 . The energy storage control unit 11 is in communication with the starting power control device 40 . The starting power control device 40 is used to control the power output of the starting power device 50 . Multiple starting power devices 50 can be provided within the power transmission system 20 . Each starting power device 50 can provide starting power for a black start. The starting power control device 40 can be provided in a one-to-one or one-to-many correspondence with the starting power device 50 to control the power output of the corresponding starting power device 50 . The starting power control device 40 and the energy storage control unit 11 can be connected and exchange data via an Ethernet network, a bus network, a wireless network, or the like.

[0079] The energy storage control unit 11 can be preconfigured with power requirement information for a black start, as well as power information and power supply types for the electrical energy that each starting electrical energy device 50 can output. If the energy storage control unit 11 determines, based on the capacity information and power requirement information of the energy storage device 12, that the capacity of the energy storage device 12 can meet the power requirement for the black start, it then controls the energy storage device 12 to output electrical energy based on the power requirement information, independently providing the starting electrical energy for the black start. For example, if the energy storage control unit 11 determines, based on the capacity of the energy storage device 12, that the electrical energy that the energy storage device 12 can output is greater than the power requirement for the black start, it determines that it can independently provide the starting electrical energy for the black start.

[0080] If the energy storage control unit 11 determines that the capacity of the energy storage device 12 does not meet the black start power requirement, it determines the power required to be output by the energy storage device 12 and the black start supplemental power. Based on the black start supplemental power and the power information of the electric energy that can be output by each starting electric energy device 50, the energy storage control unit 11 selects a starting electric energy device 50 so that the total power of the electric energy output by the selected starting electric energy devices 50 is greater than or equal to the black start supplemental power.

[0081] The energy storage control unit 11 determines the startup sequence for the energy storage device 12 and the selected startup power device 50. For example, the energy storage control unit 11 determines the startup sequence based on the power supply type of the energy storage device 12 and the selected startup power device 50, as well as the startup sequence strategy corresponding to the power supply type. Power supply types include battery power supply, thermal power supply, wind power supply, and photovoltaic power supply. The startup sequence strategy includes multiple startup priorities, for example, battery power supply has the highest startup priority, thermal power supply has a lower startup priority than battery power supply, etc. The energy storage control unit 11 determines the startup time of the energy storage device 12 and the selected startup power device 50 according to the startup sequence, and the energy storage device 12 and the selected startup power device 50 cooperate to complete the startup and recovery of the power grid. The energy storage control unit 11 sends second power scheduling information to the startup power control device 40 corresponding to the selected startup power device 50. The second power scheduling information includes the power required to be output by the startup power device 50 and the startup time information. The starting power control device 40 controls the selected starting power device 50 to output power according to the second power scheduling information.

[0082] For example, the selected starting power energy device 50 is powered by a thermal power unit, and the power supply type is a thermal power supply type. The energy storage control unit 11 can preferentially control the energy storage control unit 12 to start and output electric energy. After providing corresponding power support, the starting power energy device 50 outputs electric energy and provides power support; or, the selected starting power energy device 50 is powered by battery energy storage, and the power supply type is a battery power supply type; the energy storage control unit 11 can control the energy storage device 12 and the selected starting power energy device 50 to output electric energy synchronously.

[0083] The energy storage system includes a second communication unit 70. The energy storage control unit 11 establishes a communication connection with the starting power control device 40 through the second communication unit 70, and exchanges data with the starting power control device 40 via an Ethernet network, a bus network, a wireless network, etc. The energy storage control unit 11 may also be provided with a communication interface for establishing a communication connection with the starting power control device 40.

[0084] The energy storage control unit 11 is communicated with the starting power control device 40. When it is determined that the capacity of the energy storage device 12 can meet the total power required for the black start, the energy storage control unit 11 controls the energy storage device 12 to independently provide the starting power required for the black start. When it is determined that the capacity of the energy storage device 12 does not meet the total power required for the black start, the energy storage control unit 11 itself performs unified power coordination and scheduling, and cooperates with other starting power devices 50 to complete the black start. This can ensure the smooth completion of the black start regardless of whether the capacity of the energy storage device 12 meets or does not meet the total power required for the black start, thereby improving the success rate and stability of the black start process.

[0085] In some embodiments, as shown in FIG4 , the energy storage device includes energy storage module subunits 121, 122, ..., 12n. The energy storage control unit 11 obtains the remaining capacity of each energy storage module subunit and determines the capacity information of the energy storage device based on the remaining capacity. Based on the remaining capacity of each energy storage module subunit and the power demand information of the transmission system 20 or the first power scheduling information issued by the scheduling system 30, the energy storage control unit 11 selects one or more energy storage module subunits from the energy storage module subunits 121, 122, ..., 12n, and controls the one or more energy storage module subunits to output power to the transmission system 20. The number n of energy storage module subunits can be configured according to the voltage level and support capacity of the transmission system.

[0086] The energy storage device 12 adopts a modular multi-level cascade structure, which can improve the configuration capacity of the energy storage device; the energy storage control unit 11 detects the capacity of each energy storage module subunit and independently controls the output power of each energy storage module subunit, which can obtain accurate capacity information of the energy storage device and provide a variety of power outputs for black start based on power requirements, which can improve the control accuracy and precision of power output during the black start process.

[0087] The energy storage system includes a first communication unit 60 and a second communication unit 70. The energy storage control unit 11 establishes a communication connection with the dispatching system 30 through the first communication unit 60, and exchanges data with the dispatching system 30. The energy storage control unit 11 establishes a communication connection with the starting power control device 40 through the second communication unit 70, and exchanges data with the starting power control device 40. The first communication unit 60 and the second communication unit 70 can be set up independently or integrated with the energy storage control unit 11. The energy storage control unit 11 can also establish communication connections with the dispatching system 30 and the starting power control device 40 respectively through a communication unit (integrating the functions of the first communication unit 60 and the second communication unit 70) to exchange data. The energy storage control unit 11 itself can also be provided with a communication interface for establishing communication connections with the dispatching system 30 and the starting power control device 40 respectively.

[0088] The energy storage control unit 11 and the first communication unit 60 can be connected via a bus, a network cable, or the like. The first communication unit 60 and the dispatching system 30 can be connected via an Ethernet network, a bus network, a wireless network, or the like. The energy storage control unit 11 receives power demand information sent by the dispatching system 30 via the first communication unit 60. If it is determined that the capacity of the energy storage device meets the power requirement for a black start, the energy storage control unit 11 returns an indication confirming that the black start is met to the dispatching system 30 via the first communication unit 60. If it is determined that the capacity of the energy storage device does not meet the power requirement for a black start, the energy storage control unit 11 sends capacity information to the dispatching system 30 via the first communication unit 60 and receives the first electric energy dispatch information returned by the dispatching system 30.

[0089] The energy storage control unit 11 is communicatively connected to the dispatching system 30 via the first communication unit 60, and can obtain comprehensive and accurate black start power requirement information from the dispatching system 30. When it is determined that the capacity of the energy storage device does not meet the total power required for the black start, the dispatching system 30 can be accepted for unified power coordination and scheduling. Whether the capacity of the energy storage device meets or does not meet the total power required for the black start, the black start can be successfully completed, thereby improving the success rate and stability of the black start process.

[0090] The energy storage control unit 11 and the second communication unit 70 can be connected via a bus, a network cable, or the like. The second communication unit 70 and the starting power control device 40 can be connected via an Ethernet network, a bus network, a wireless network, or the like. If it is determined that the capacity of the energy storage device does not meet the power requirement for a black start, the energy storage control unit 11 sends the second power scheduling information to the starting power control device 40 via the second communication unit 70.

[0091] The energy storage control unit 11 is in communication with the starting power control device 40 via the second communication unit 70. When it is determined that the capacity of the energy storage device does not meet the total power required for the black start, the energy storage control unit 11 performs unified power coordination and scheduling, and collaborates with other starting power devices to complete the black start. This ensures the smooth completion of the black start even when the capacity of the energy storage device meets or does not meet the total power required for the black start, thereby improving the success rate and stability of the black start process.

[0092] In some embodiments, the power transmission system may be a variety of power transmission systems, including a DC bus, a converter, and an AC grid. The DC bus includes a positive DC bus and a negative DC bus, and the ends of the positive DC bus and the negative DC bus are respectively connected to the AC grid through converters. For example, the power transmission system is a flexible DC transmission system, which may be a high-voltage flexible DC transmission system, a sea breeze flexible DC transmission system, a medium- and low-voltage flexible DC distribution network system, etc. Flexible DC transmission is a new transmission technology based on voltage source converters, self-shutoff devices, and pulse width modulation technology. It has the advantages of being able to supply power to passive networks, preventing commutation failures, and easily forming a multi-terminal DC system. As shown in Figure 5, the flexible DC transmission system includes a positive DC bus 25, a negative DC bus 26, converters 21 and 22, and AC grids 23 and 24. AC grids 23 and 24 can be of various types, and converters 21 and 22 can be of various types, such as voltage-sourced converters (VSCs). The positive DC bus 25 and the negative DC bus 26 are connected to the AC grids 23 and 24 via converters 21 and 22, respectively. A starting power control device and a starting power device can be provided within AC grid 23.

[0093] Energy storage module subunits 121, 122, ..., 12n, etc. are connected in series or in parallel to form an energy storage device, with both ends of the energy storage device connected to the positive DC bus 25 and the negative DC bus 26, respectively. Based on the remaining capacity of energy storage module subunits 121, 122, ..., 12n, etc., as well as the power demand information for the black start of the power transmission system or the first power scheduling information sent by the scheduling system 30, the energy storage control unit 11 selects and controls one or more energy storage module subunits 121, 122, ..., 12n to output power to the positive DC bus 25 and the negative DC bus 26, thereby providing starting power to the AC power grids 23 and 24.

[0094] The disclosed energy storage system is installed on the DC side of the power transmission system. The energy storage control unit 11 selects energy storage module subunits to output power to the DC bus based on the remaining capacity of the energy storage device and the power demand information or power scheduling information of the power transmission system for a black start, thereby providing the power transmission system with starting energy for the black start. The modular multi-level cascaded energy storage device enables distributed integration of multiple energy storage module subunits, implementing a DC direct-connect energy storage method in the power transmission system. This has the advantages of a high degree of modularity, improving the accuracy of controlling output power, and effectively enhancing the output power regulation capability.

[0095] In some embodiments, as shown in FIG6A , VSC converters 21 and 22 are respectively configured at the sending and receiving ends of the HVDC flexible power transmission system. VSC converters 21 and 22 are connected to AC grids 23 and 24, respectively. An energy storage device is configured on the DC side of the HVDC flexible power transmission system. The energy storage device is composed of energy storage module subunits 121, 122, and 12n connected in series. A current limiting circuit is provided on the connection line between the first end of the energy storage device and the positive DC bus 25 or the connection line between the second end of the energy storage device and the negative DC bus 26. The number of energy storage reactors can be one or two, and they are provided on the connection line between the first end of the energy storage device and the positive DC bus 25 and / or the connection line between the second end of the energy storage device and the negative DC bus. For example, the energy storage device is connected between the positive DC bus 25 and the negative DC bus 26 via energy storage reactors 18 and 19. An isolation switch may also be provided on the connection line between the first end of the energy storage device and the positive DC bus 25, or on the connection line between the second end of the energy storage device and the negative DC bus 26. For example, an isolation switch 16 may be provided on the connection line between the first end of the energy storage device and the positive DC bus 25. Isolation switch 16 may be an isolating switch, etc., which can isolate the energy storage device from the power grid, forming a clearly visible disconnect point, facilitating maintenance and ensuring personnel safety.

[0096] Setting a modular multi-level cascaded direct-mounted energy storage device on the DC side of the high-voltage flexible DC transmission system can increase the capacity of the energy storage device and improve the grid's output power regulation capability. Connecting the energy storage device and DC busbars 25, 26 via current-limiting circuits and energy storage reactors 18, 19 can reduce the instantaneous surge current generated when the energy storage device and DC busbars 25, 26 are connected to the grid, thereby improving the safety of the energy storage system and extending the service life of the energy storage device.

[0097] The current limiting circuit can have various structures. For example, the current limiting circuit includes a starting resistor 171 and a bypass switch 172, which are connected in parallel. By providing the starting resistor 171, the peak current of charging or discharging can be limited, providing protection. The energy storage control unit 11 is connected to the bypass switch 172. When the energy storage device is in the initial charging or discharging state, the energy storage control unit 11 controls the bypass switch 172 to open. When the energy storage device is in the charging or discharging operating state, the energy storage control unit 11 closes the bypass switch 172 to short-circuit the starting resistor 171 and reduce the power consumed by the starting resistor 171.

[0098] The energy storage module subunit includes a power unit 1221 and an energy storage unit 1222. Energy storage unit 1222 is connected to power unit 1221, and energy storage unit 1222 transmits electrical energy through power unit 1221 and is charged. Power unit 1221 can adopt a variety of circuit structures. For example, power unit 1221 includes a rectifier circuit, which can be a half-bridge, full-bridge, or quasi-full-bridge rectifier circuit. As shown in Figure 6A, power unit 1221 includes a half-bridge rectifier circuit.

[0099] Energy storage unit 1222 can employ a variety of circuit structures. For example, energy storage unit 1222 includes an energy storage circuit formed by a battery pack 1225 for storing electrical energy and a pre-charge circuit 1224 connected in series. The number of pre-charge circuits 1224 can be one or more, and can be provided on one or both sides of battery pack 1225. For example, a contactor, which is a switching component, can be provided in the energy storage circuit. For example, contactors 1223 and 1230 can be provided in the energy storage circuit. Battery pack 1225 can include a lithium battery pack, etc.

[0100] The pre-charge circuit can adopt various structures. For example, pre-charge circuit 1224 includes a first switch 1226, a second switch 1227, and a pre-charge resistor 1228, with the first switch 1226 and the pre-charge resistor 1228 connected in series. A pre-charge circuit can also be set on the other side of the battery pack 1225, including a first switch 1231, a second switch 1232, and a pre-charge resistor 1233, with the first switch 1231 and the pre-charge resistor 1233 connected in series.

[0101] During the initial stages of charging or discharging of battery pack 1225, closing first switch 1226 and first switch 1231 activates pre-charging resistors 1228 and 1233, thereby limiting the peak current of charging or discharging, providing protection. When battery pack 1225 is in normal charging and discharging operation, closing second switch 1227 and second switch 1232 short-circuits pre-charging resistors 1228 and 1233, reducing the energy consumed by activating pre-charging resistor 1228.

[0102] As shown in FIG6B , a control subunit 1229 is provided in each energy storage module subunit, and each control subunit 1229 is connected to the energy storage control unit 11. The control subunit 1229 receives instructions issued by the energy storage control unit 11 and performs corresponding functions based on the instructions. The energy storage control unit 11 obtains the remaining capacity of the battery pack from the control subunit 1229, adds the remaining capacity of the battery packs of each energy storage module subunit, and determines the capacity information of the energy storage device. The energy storage control unit 11 sends a control instruction to the control subunit 1229 to control the corresponding energy storage module subunit to output electrical energy. The control subunit 1229 can be implemented in various ways. For example, the control subunit 1229 includes one or more processors and a memory. The memory can be a volatile memory and / or a non-volatile memory for storing one or more computer program instructions. The processor can execute the program instructions to communicate with the energy storage control unit and complete other functions that it needs to process.

[0103] The control subunit 1229 is connected to each corresponding battery pack 1225, receives a capacity acquisition instruction sent by the energy storage control unit 11, obtains the remaining capacity of the battery pack 1225, and sends the remaining capacity of the battery pack 1225 to the energy storage control unit 11. The control subunit 1229 is connected to the power unit 1221 and the pre-charge circuit, receives a control instruction sent by the energy storage control unit 11, controls the state of the power unit 1221, and controls the on / off of the pre-charge circuit.

[0104] The control instructions may be of various types. For example, if the control instruction is an output power control instruction, the control subunit 1229 controls the power unit 1221 to be in an on state and controls the pre-charge circuit to be conductive, so that the battery pack 1225 outputs power through the power unit 1221. If the control instruction is a stop power output control instruction, the control subunit 1229 controls the power unit 1221 to be in an off state and controls the pre-charge circuit to be disconnected, so that the battery pack 1225 stops outputting power through the power unit 1221.

[0105] The pre-charge circuit 1224 can adopt a variety of structures, and the control subunit 1229 can use a variety of methods to control the on and off of the pre-charge circuit. As shown in Figure 6C, the control subunit 1229 is connected to the first switch 1226, the first switch 1231, the second switch 1227, and the second switch 1232 respectively. The output power control instruction includes an initial output power control instruction and a normal output power control instruction. Upon receiving the initial output power control instruction and the normal output power control instruction, the control subunit 1229 controls the power unit 1221 to be in the on state. When the output power control instruction is the initial output power control instruction, the control subunit 1229 closes the first switch 1226 and the first switch 1231 and disconnects the second switch 1227 and the second switch 1232 according to the instruction, and uses the pre-charging resistor 1228 and the pre-charging resistor 1233 to limit the current; when the output power control instruction is the normal output power control instruction, the control subunit 1229 closes the first switch 1226, the first switch 1231, the second switch 1227 and the second switch 1232 according to the instruction to short-circuit the pre-charging resistor 1228 and the pre-charging resistor 1233.

[0106] During the initial stages of charging and discharging, the energy storage control unit sends an initial output power control instruction to the control subunit. The control subunit closes the first switch to activate the pre-charge resistor, limiting the peak current during charging or discharging, providing protection and improving the safety of the battery pack. When the battery pack is in normal charging and discharging operation, the energy storage control unit sends a normal output power control instruction to the control subunit. The control subunit closes the first and second switches to short-circuit the pre-charge resistor, reducing the energy consumed by activating the pre-charge resistor.

[0107] Energy storage module subunits 121, 122, ..., 12n, etc., use battery packs as their energy source. The battery pack's charging and discharging functions enable the energy storage module subunits to provide stable, long-term electrical energy, offering advantages such as good harmonic characteristics and a low equivalent switching frequency. Power unit 1221 controls the charging and discharging of the battery pack, improving the stability of the battery pack's charging and discharging currents. This effectively prevents overcharging and over-discharging, making the battery pack's charging and discharging safer and more reliable, and extending the battery pack's service life. Energy storage unit 1222, by providing a pre-charge circuit, can limit the battery pack's peak current, providing protection and reducing the battery pack's inrush current. This improves the battery pack's operational safety and extends its service life.

[0108] A variety of detection units can be used for fault detection. Fault detection units 13 and 14 are respectively provided on the positive DC bus 25 and the negative DC bus 26. There can also be one fault detection unit, provided on either the positive DC bus 25 or the negative DC bus 26. Fault detection units 13 and 14 can use a variety of detection devices to detect current, voltage, and other data on the positive DC bus 25 and / or the negative DC bus 26.

[0109] The DC control and protection unit 15 is connected to the VSC converters 21 and 22. The DC control and protection unit 15 can utilize various detection devices to obtain data from the VSC converters 21 and 22 and fault status information from the AC grids 23 and 24. The VSC converter 21 and 22 data includes data such as converter node voltages and corresponding output or input power. Fault status information includes grid fault information transmitted by the management system within the AC grids 23 and 24. The energy storage control unit 11 can connect to and exchange data with the starting power control device via the DC control and protection unit 15. Either the fault detection unit or the DC control and protection unit alone can be provided, or both can be provided.

[0110] Fault detection units 13 and 14 monitor current data (or voltage data) on the positive DC bus 25 and negative DC bus 26 in real time and transmit this data to the energy storage control unit 11 via a bus, optical fiber, or wireless communication. The DC control and protection unit 15 acquires real-time data from the VSC converters 21 and 22 and fault status information from the AC grid 23 and 24, and transmits this data to the energy storage control unit 11 via a bus, optical fiber, or wireless communication. Based on one or more of the current data, converter data, and fault status information, the energy storage control unit 11 determines whether the AC grid 23 and 24 is operating normally and whether a black start is required.

[0111] For example, if the energy storage control unit 11 determines that the current on the positive DC bus 25 and the negative DC bus 26 is 0, or the data of the VSC converters 21 and 22 is that the node voltage is 0 and the corresponding output or input power is 0, or the fault status information of the AC power grid 23 and 24 obtained through the DC control and protection unit 15 is that the power grid is in a power-off state, etc., then the energy storage control unit 11 determines that the transmission system is operating abnormally and is in a power-off state, and a black start is required.

[0112] Based on the detection of the current on the DC bus by the fault detection units 13 and 14, the data of the VSC converters 21 and 22 and the fault status information of the AC power grids 23 and 24 obtained by the DC control and protection unit 15 can enable the energy storage control unit 11 to respond accurately and quickly when a power grid fault occurs, and can quickly perform a black start and troubleshoot the fault, thereby improving the reliability of the transmission system and enhancing the management level of the transmission system.

[0113] When energy storage control unit 11 determines that a black start is required, it adjusts the operating mode to the black start mode. Energy storage control unit 11 determines the remaining capacity of energy storage module subunit 121, energy storage module subunit 122, ..., energy storage module subunit 12n by obtaining the remaining SOC (State of Charge) information of the battery cells in energy storage module subunit 121, energy storage module subunit 122, ..., energy storage module subunit 12n. Energy storage control unit 11 obtains capacity information of the energy storage device based on the remaining capacity of all energy storage module subunits.

[0114] The energy storage control unit 11 sends a power request to the dispatching system 30 and receives information from the dispatching system regarding the power requirements of the transmission system for a black start. If the energy storage control unit 11 determines that the capacity of the energy storage device meets the power requirements for a black start and that the energy storage device has independent startup capabilities, it returns an indication confirming that the black start is met to the dispatching system 30. Based on the remaining capacity of the storage device and the power requirements of the transmission system for a black start, the energy storage control unit 11 selects and controls one or more energy storage module subunits 121, 122, ..., 12n to output power to the positive DC bus 25 and the negative DC bus 26.

[0115] If the energy storage control unit 11 determines that the capacity of the energy storage device does not meet the power requirement for the black start and that the energy storage device does not have independent startup capabilities, it sends the capacity information of the energy storage device to the dispatching system 30. The dispatching system 30 determines the power required by the energy storage device based on the capacity information of the energy storage device. Based on the power deviation between the required power output of the energy storage device and the power requirement for the black start, it selects other starting power sources. The other starting power sources can be units in the wind power grid, new energy power grid, etc., and determines the startup order of the energy storage device and other starting power sources. For example, the dispatching system 30 reallocates the power required for the black start, configures other starting power sources that are closest to the power deviation, and determines the startup order.

[0116] The dispatching system 30 sends first power dispatch information to the energy storage control unit 11. This first power dispatch information includes the required output power and startup time of the energy storage device. For example, if the required output power of the energy storage device is 100W, the startup time information indicates the time it takes for the energy storage device to start and output power. The dispatching system 30 can control the energy storage system of the present disclosure and other startup power sources to collaborate according to a predetermined priority order, sequentially inputting power to provide the transmission system with startup power for a black start.

[0117] The energy storage control unit 11 selects and controls one or more energy storage module subunits 121, 122, ... 12n to output electric energy to the positive DC bus 25 and the negative DC bus 26 based on the remaining capacity of the energy storage device and the first electric energy scheduling information sent by the scheduling system 30.

[0118] As shown in FIG6A , the energy storage control unit 11 selects and controls one or more energy storage module subunits 121, 122, ..., 12n based on the remaining capacity of the energy storage device and the power demand information or the first electric energy dispatching information sent by the dispatching system 30 to output a DC bus voltage to the positive DC bus 25 and the negative DC bus 26, thereby driving the VSC converters 21, 22 and the devices in the AC power grids 23, 24 to start and recover.

[0119] For example, the energy storage control unit 11 can determine the number and location of energy storage module subunits that need to output electrical energy based on the remaining capacity of the energy storage device and the power demand information or first electrical energy dispatch information sent by the dispatch system 30, and adopt multiple SOC balancing control strategies. It can also control the selected energy storage module subunits to output a DC bus voltage to the DC bus, thereby maintaining the DC bus voltage stability. Through power regulation, the SOC balance of the battery cells of different energy storage module subunits can be ensured. The energy storage control unit 11 controls one or more energy storage module subunits to output a DC bus voltage to the DC bus, driving the VSC converters 21 and 22 to start up in sequence. The electrical energy output by the one or more energy storage module subunits then drives the AC grids 23 and 24 through the VSC converters 21 and 22 to complete grid startup and recovery.

[0120] By using the SOC balancing control strategy to control the DC bus voltage output by the energy storage module sub-units through the energy storage control unit 11, the stability of the DC bus voltage can be maintained, the SOC of the battery packs of each energy storage module sub-unit can be adjusted to converge, the available capacity of the battery pack can be better utilized, the availability of the battery pack can be improved, the electric energy output by the energy storage device can be more stable, and the service life of the battery pack can be extended.

[0121] When the power transmission system is operating normally, energy storage control unit 111 controls the energy storage device to charge based on its capacity information. If energy storage control unit 111 determines that AC grids 23 and 24 are operating normally based on one or more of the current or voltage data on the DC bus, converter data, and fault status information, it configures the energy storage device to charge and can employ various SOC balancing control strategies for charging control.

[0122] The energy storage control unit 11 controls the energy storage device to charge when charging is suitable, can realize power conversion and energy storage, ensure that the energy storage device is fully charged, can provide stable electric energy, ensure the smooth completion of the black start process, and improve the success rate and stability of the black start process.

[0123] The energy storage system disclosed in the present invention can solve the problem of being unable to successfully complete a black start when using hydropower units, wind turbines, and energy storage systems to provide starting power after a power transmission system failure. It can accurately match the power requirements of the black start and improve the success rate and stability of the black start process.

[0124] In some embodiments, the present disclosure provides a power transmission system comprising the energy storage system described in any of the above embodiments. The power transmission system may be a flexible direct current transmission system or other system. The power transmission system of the present disclosure has the advantages of the energy storage system described in any of the above embodiments.

[0125] In some embodiments, the present disclosure provides a control method for a black start of a power transmission system, wherein the energy storage system includes an energy storage device and an energy storage control unit, and the control method for a black start of a power transmission system of the present disclosure is executed in the energy storage control unit. FIG7 is a flow diagram of some embodiments of the control method for a black start of a power transmission system of the present disclosure, as shown in FIG7:

[0126] Step 701 : When a power transmission system fails, obtain capacity information of an energy storage device and power requirement information of the power transmission system for a black start.

[0127] Step 702 : Based on the capacity information and the power demand information, the energy storage device is controlled to output electric energy, so as to provide starting electric energy for a black start to the power transmission system.

[0128] The energy storage control unit can be implemented in a variety of ways to implement the control methods for black start of a power transmission system according to various embodiments of the present disclosure. For example, the energy storage control unit includes one or more processors and a memory. The processor can be a central processing unit (CPU) or other processing unit with data processing capabilities and / or instruction execution capabilities. The memory can be a volatile memory and / or non-volatile memory for storing one or more computer program instructions. The processor can execute the program instructions to implement the control methods for black start of a power transmission system according to various embodiments of the present disclosure or other desired functions.

[0129] The disclosed control method for a black start of a power transmission system controls the output power of an energy storage device based on its capacity information and the power requirement information for the black start. This method can accurately match the power requirement for the black start, ensure the smooth completion of the black start, and improve the success rate and stability of the black start process.

[0130] In some embodiments, when it is determined based on the capacity information and the power demand information that the capacity of the energy storage device meets the power requirement for a black start, the power that the energy storage device needs to output is determined based on the power demand information to control the energy storage device from outputting electrical energy; alternatively, when it is determined based on the capacity information and the power demand information that the capacity of the energy storage device does not meet the power requirement for a black start, the power that the energy storage device needs to output and the start-up time of the energy storage device are determined based on at least one of the capacity information and the power demand information to control the energy storage device from outputting electrical energy.

[0131] The energy storage control unit determines the power that the energy storage device needs to output, or the power that the energy storage device needs to output and the startup time of the energy storage device, when the capacity of the energy storage device meets or does not meet the total power required for the black start. This is used to control the energy storage device to output the starting power to complete the black start independently or in collaboration with other systems, thereby improving the success rate and stability of the black start process.

[0132] In some embodiments, the energy storage control unit is in communication with the dispatching system. FIG8 is a flow chart of controlling the energy storage device to output electric energy in some embodiments of the control method for black start of a power transmission system disclosed herein, as shown in FIG8 :

[0133] Step 801: Receive power demand information sent by the scheduling system.

[0134] Step 802 : Determine whether the capacity of the energy storage device meets the power requirement of the black start based on the capacity information and the power requirement information. If yes, proceed to step 803 ; if not, proceed to step 804 .

[0135] Step 803: Return the indication information confirming that the black start conditions are met to the dispatching system, and control the energy storage device to output electric energy based on the power demand information.

[0136] Step 804: Send capacity information to the dispatching system; and control the energy storage device to output electric energy based on the first electric energy dispatching information returned by the dispatching system.

[0137] The dispatch system is equipped with a functional device for communicating with the energy storage control unit and performing other processing functions. This functional device can be implemented in various ways. For example, the functional device includes one or more processors and memory. The memory can be volatile memory and / or non-volatile memory for storing one or more computer program instructions. The processor can execute the program instructions to achieve communication with the energy storage control unit and complete other processing functions required by the processor.

[0138] By obtaining the transmission system's power demand information for black starts from the dispatching system, comprehensive and accurate power demand information can be obtained. This ensures the smooth completion of black starts even when the capacity of the energy storage device meets or does not meet the total power required for black starts, thereby improving the success rate and stability of the black start process.

[0139] FIG9 is a schematic diagram of a process of sending electric energy dispatching information by a dispatching system in some embodiments of the control method for black start of a power transmission system disclosed in the present invention, as shown in FIG9 :

[0140] Step 901 : When it is determined based on the capacity information that the capacity of the energy storage device does not meet the power requirement of the black start, the dispatching system determines the power that the energy storage device needs to output based on the capacity information.

[0141] In step 902 , the dispatching system selects other starting power sources based on the power deviation between the required output power and the power requirement of the black start, and determines the starting sequence of the energy storage device and the other starting power sources.

[0142] Step 903: The dispatching system sends first electric energy dispatching information to the energy storage device; wherein the first electric energy dispatching information carries information including: required output power and start-up time information.

[0143] Through unified power coordination and scheduling through the dispatching system, the starting power required by the energy storage device and the startup sequence are determined, so that the energy storage system and other systems can cooperate to complete the black start, which can ensure the smooth completion of the black start and improve the success rate and stability of the black start process.

[0144] FIG10 is a schematic diagram of a flow chart of controlling the energy storage device to output electric energy in some embodiments of the control method for black start of a power transmission system disclosed herein, as shown in FIG10 :

[0145] Step 1001 : Determine whether the capacity of the energy storage device meets the power requirement of the black start based on the capacity information and the power requirement information. If yes, proceed to step 1002 ; if not, proceed to step 1003 .

[0146] Step 1002: Control the energy storage device to output electric energy based on the power demand information.

[0147] Step 1003: Determine the power that the energy storage device needs to output and the supplementary power for black start.

[0148] Step 1004 : Select a starting electric energy device based on the supplemental power and determine a starting sequence of the energy storage device and the selected starting electric energy device.

[0149] Step 1005: Send second power scheduling information to the starting power control device corresponding to the selected starting power device. The second power scheduling information carries information such as the power required to be output by the starting power device and the starting time information.

[0150] The kinetic energy control system is provided with a functional device for communicating with the energy storage control unit and performing other processing functions. This functional device can be implemented in various ways. For example, the functional device includes one or more processors and memory. The memory can be volatile memory and / or non-volatile memory for storing one or more computer program instructions. The processor can execute the program instructions to achieve communication with the energy storage control unit and complete other functions that the processor needs to process.

[0151] By performing unified power coordination and scheduling through the energy storage control unit itself, the black start can be successfully completed even when the capacity of the energy storage device meets or does not meet the total power required for the black start, thereby improving the success rate and stability of the black start process.

[0152] In some embodiments, the energy storage device includes multiple energy storage module subunits. FIG11 is a flow chart of power output control in some embodiments of the control method for black start of a power transmission system disclosed in the present invention, as shown in FIG11:

[0153] Step 1101 : Based on the remaining capacity and the power demand information of the power transmission system for black start or the first power scheduling information, select and control at least one energy storage module subunit from a plurality of energy storage module subunits to output power to the power transmission system.

[0154] By detecting the capacity of each energy storage module subunit in an energy storage device with a multi-level cascade structure and independently controlling the output power of each energy storage module subunit, accurate capacity information of the energy storage device can be obtained, and a variety of power outputs for black start can be provided based on power requirements, which can improve the accuracy and precision of power output control during the black start process.

[0155] In some embodiments, the power transmission system includes a flexible direct current (HVDC) power transmission system; the flexible HVDC power transmission system includes a DC bus, a converter, and an AC grid; the two ends of the DC bus are connected to the AC grid through the converter, respectively; a plurality of energy storage module subunits are connected in series or in parallel to form an energy storage device, and the energy storage device is connected to the DC bus.

[0156] There are a variety of methods that can be used to select and control the energy storage module subunits to output electrical energy to the power transmission system. For example, based on the remaining capacity and the power demand information of the power transmission system for black start or the first power scheduling information, at least one energy storage module subunit is selected and controlled to output electrical energy to the DC bus to provide starting power to the AC power grid. There are a variety of methods that can be used to control the energy storage module subunits to output electrical energy to the DC bus. For example, based on the remaining capacity and the power demand information of the power transmission system for black start or the first power scheduling information, and using the SOC balancing control strategy, at least one energy storage module subunit is selected and controlled to output the DC bus voltage to the DC bus, driving the converters located at both ends of the DC bus to start in sequence, so that the electrical energy output by at least one energy storage module subunit drives the equipment in the AC power grid to start and recover via the converter.

[0157] By using the SOC balancing control strategy to select and control the output DC bus voltage of the energy storage module sub-units, the stability of the DC bus voltage can be maintained, and the SOC convergence of the battery packs of each energy storage module sub-unit can be adjusted to better utilize the available capacity of the battery pack and improve the availability of the battery pack.

[0158] In some embodiments, the SOC balancing control strategy includes a ranking selection strategy. The SOC information of each energy storage module subunit is sorted to obtain an SOC ranking result. The SOC balancing control strategy is then used to select at least one energy storage module subunit based on the SOC ranking result. For example, the SOC information of each energy storage module subunit is sorted from high to low, and the ranking selection strategy is used to select at least one energy storage module subunit that ranks at the top of the SOC ranking result to meet the power demand or power scheduling requirements of the transmission system for black start.

[0159] The SOC balancing control strategy includes a variety of discharge control methods, such as the PI control method. A sub-controller is provided in each energy storage module sub-unit, which can communicate data with the energy storage control unit. The energy storage control unit controls the discharge of the energy storage module sub-unit by sending a control command to the sub-controller. The energy storage control unit can pre-set at least one of the reference voltage and the reference current, and collect at least one of the real-time voltage and the real-time current of the selected energy storage module sub-unit. The energy storage control unit can use the PI control method to perform PI control on at least one energy storage module sub-unit based on the reference voltage and / or reference current and the real-time voltage and / or real-time current of at least one energy storage module sub-unit, so as to output the DC bus voltage to the DC bus.

[0160] Based on the SOC balancing control strategy and according to the SOC sorting results, the energy storage module subunits are selected, and the PI control method is used to control the selected energy storage module subunits to output power to the DC bus. This can improve the accuracy of controlling the output power and enhance the success rate and stability of the black start process.

[0161] In some embodiments, the energy storage device is connected to the DC bus via an isolating switch, a current-limiting circuit, and an energy storage reactor. The current-limiting circuit includes a starting resistor and a bypass switch, which are connected in parallel. When the energy storage device is in a charge-discharge operating state, the bypass switch is controlled to close to short-circuit the starting resistor. By closing the bypass switch to short-circuit the starting resistor during the charge-discharge operating state, the energy consumed by the starting resistor can be reduced.

[0162] The energy storage system includes a fault detection unit and a DC control and protection unit. The fault detection unit is located on the DC bus and detects the DC bus current data (or voltage data). The DC control and protection unit is connected to the converter to obtain converter data and AC grid fault status information. A determination is made based on at least one of the current data, converter data, and fault status information to determine whether the AC grid requires a black start. Fault detection based on DC bus current data, converter data, and AC grid fault status information enables accurate and rapid response to grid faults, enabling timely black start and troubleshooting, thereby improving the reliability of the power transmission system.

[0163] Under normal operation of the transmission system, the energy storage device is controlled to charge according to the capacity information. This can ensure that the energy storage device provides stable power, ensure the smooth completion of the black start process, and improve the success rate and stability of the black start process.

[0164] In some embodiments, the present disclosure provides an energy storage control unit. Figure 12 is a block diagram of an energy storage control unit according to one embodiment of the present disclosure. As shown in Figure 12, the energy storage control unit may include a memory 1201, a processor 1202, a communication interface 1203, and a bus 1204. Memory 1201 is used to store instructions. Processor 1202 is coupled to memory 1201 and is configured to execute, based on the instructions stored in memory 1201, the control method for black start of a power transmission system according to any of the above-described embodiments.

[0165] Memory 1201 can be high-speed RAM, non-volatile memory, or a memory array. Memory 1201 can also be divided into blocks, and the blocks can be combined into virtual volumes according to certain rules. Processor 1202 can be a central processing unit (CPU), an application-specific integrated circuit (ASIC), or one or more integrated circuits configured to implement the control method for black start of a power transmission system disclosed herein.

[0166] In one embodiment, the present disclosure provides a computer-readable storage medium storing computer instructions, wherein the instructions are executed by a processor to implement the control method for black start of a power transmission system in any of the above embodiments.

[0167] The computer-readable storage medium can adopt any combination of one or more readable media. The readable medium can be a readable signal medium or a readable storage medium. The readable storage medium can, for example, include but is not limited to a system, device or component of electricity, magnetism, light, electromagnetic, infrared, or semiconductor, or any combination thereof. More specific examples (non-exhaustive enumeration) of readable storage media can include: an electrical connection with one or more wires, a portable disk, a hard disk, a random access memory (RAM), a read-only memory (ROM), an erasable programmable read-only memory (EPROM or flash memory), an optical fiber, a portable compact disk read-only memory (CD-ROM), an optical storage device, a magnetic storage device, or any suitable combination thereof.

[0168] The present disclosure is described with reference to the flowcharts and / or block diagrams of the methods, devices (systems) and computer program products according to the embodiments of the present disclosure. It should be understood that each process and / or box in the flowchart and / or block diagram and the combination of the processes and / or boxes in the flowchart and / or block diagram can be implemented by computer program instructions. These computer program instructions can be provided to a processor of a general-purpose computer, a special-purpose computer, an embedded processor or other programmable data processing device to produce a machine, so that the instructions executed by the processor of the computer or other programmable data processing device generate a device for implementing the functions specified in one or more processes in the flowchart and / or one or more boxes in the block diagram.

[0169] These computer program instructions may also be stored in a computer-readable memory that can direct a computer or other programmable data processing device to operate in a specific manner, so that the instructions stored in the computer-readable memory produce a product including an instruction device that implements the functions specified in one or more processes in the flowchart and / or one or more boxes in the block diagram.

[0170] The methods and systems of the present disclosure may be implemented in many ways. For example, the methods and systems of the present disclosure may be implemented by software, hardware, firmware, or any combination of software, hardware, and firmware. The above order of steps for the method is for illustration only, and the steps of the method of the present disclosure are not limited to the order specifically described above unless otherwise specified. In addition, in some embodiments, the present disclosure may also be implemented as programs recorded in a recording medium, which include machine-readable instructions for implementing the methods according to the present disclosure. Therefore, the present disclosure also covers recording media that store programs for executing the methods according to the present disclosure.

[0171] Although the present application has been described with reference to preferred embodiments, various modifications may be made thereto and components may be substituted with equivalents without departing from the scope of the present application. In particular, the various technical features described in the various embodiments may be combined in any manner as long as there are no structural conflicts. The present application is not limited to the specific embodiments disclosed herein, but encompasses all technical solutions within the scope of the claims.

Claims

1. An energy storage system comprising: Energy storage device and energy storage control unit; The energy storage control unit is used to control the energy storage device to output electric energy in the event of a power transmission system failure, based on the capacity information of the energy storage device and the power requirement information of the power transmission system for black start, so as to provide the power transmission system with starting electric energy for black start.

2. The energy storage system according to claim 1, comprising: a first communication unit; The energy storage control unit establishes a communication connection with the scheduling system through the first communication unit; The energy storage control unit is configured to receive the power demand information sent by the dispatching system; if it is determined that the capacity of the energy storage device meets the power demand of the black start, return an indication to the dispatching system confirming that the black start is met; or, if it is determined that the capacity of the energy storage device does not meet the power demand of the black start, send the capacity information to the dispatching system; The energy storage device is controlled to output electric energy based on the power demand information or the first electric energy scheduling information returned by the scheduling system.

3. The energy storage system according to claim 1, comprising: a second communication unit; The energy storage control unit establishes a communication connection with the starting power control device through the second communication unit; The energy storage control unit is configured to control the energy storage device to output electric energy based on the power demand information when it is determined that the capacity of the energy storage device meets the power demand of the black start; or, when it is determined that the capacity of the energy storage device does not meet the power demand of the black start, send second electric energy scheduling information to the starting electric energy control device, and control the energy storage device to output electric energy based on the power information and time that the energy storage device needs to output.

4. The energy storage system according to claim 1, wherein: The energy storage device includes a plurality of energy storage module subunits; the plurality of energy storage module subunits are connected in series to form the energy storage device, and each energy storage subunit is respectively connected to the energy storage control unit; The energy storage control unit is used to obtain the remaining capacity of the energy storage subunit to determine the capacity information of the energy storage device; and control the energy storage subunit to output electric energy.

5. The energy storage system according to claim 4, wherein: The energy storage module subunit includes: a control subunit, a power unit and an energy storage unit; the energy storage unit includes an energy storage circuit formed by a battery pack and a pre-charge circuit in series, the energy storage circuit is connected in parallel with the first end of the corresponding power unit; the second ends of each power unit are connected in series; The control subunit is respectively connected to the corresponding power unit, battery pack, pre-charge circuit, and is also connected to the energy storage control unit; The control subunit is used to return the remaining capacity of the battery pack upon receiving a capacity acquisition instruction sent by the energy storage control unit; and to control the state of the power unit and the on / off of the pre-charging circuit upon receiving a control instruction sent by the energy storage control unit.

6. The energy storage system according to claim 1, comprising: Current limiting circuits and energy storage reactances; The current limiting circuit is provided on a connection line between the first end or the second end of the energy storage device and the DC bus of the power transmission system; And / or, the energy storage reactance is provided on a connection line between the first end and / or the second end of the energy storage device and a DC busbar of the power transmission system.

7. The energy storage system according to claim 6, wherein: The current limiting circuit includes a starting resistor and a bypass switch connected in parallel with the starting resistor; The energy storage control unit is connected to the bypass switch and is used to control the opening or closing of the bypass switch so as to use the starting resistor for current limiting or short-circuiting the starting resistor.

8. The energy storage system according to claim 1, further comprising: a fault detection unit, disposed on a DC bus of the power transmission system and configured to detect current data of the DC bus; and / or, a DC control and protection unit connected to the converter of the power transmission system, and configured to obtain data of the converter and fault status information of the AC power grid of the power transmission system connected to the converter; The energy storage control unit is connected to the fault detection unit and / or the DC control and protection unit, and is used to determine whether a black start is required based on at least one of the current data, the converter data and the fault status information.

9. A power transmission system comprising: The energy storage system according to any one of claims 1 to 8.

10. The power transmission system according to claim 9, wherein: The power transmission system includes: a DC bus, a converter and an AC grid; the DC bus includes: a positive DC bus and a negative DC bus; both ends of the positive DC bus and the negative DC bus are connected to the AC grid through the converter respectively; The first end and the second end of the energy storage device of the energy storage system are respectively connected to the positive DC bus and the negative DC bus.

11. A control method for black start of a power transmission system, comprising: In the event of a power transmission system failure, obtaining capacity information of the energy storage device and power demand information of the power transmission system for a black start; The energy storage device is controlled to output electric energy based on the capacity information and the power demand information, so as to provide starting electric energy for performing a black start to the power transmission system.

12. The control method according to claim 11, wherein controlling the energy storage device to output electric energy based on the capacity information and the power demand information to provide starting electric energy for performing a black start on the power transmission system comprises: In the case where it is determined based on the capacity information and the power requirement information that the capacity of the energy storage device meets the power requirement of the black start, determining the power that the energy storage device needs to output according to the power requirement information to control the energy storage device to output electric energy; or When it is determined based on the capacity information and the power requirement information that the capacity of the energy storage device does not meet the power requirement of the black start, the power that the energy storage device needs to output and the start-up time of the energy storage device are determined according to at least one of the capacity information and the power requirement information to control the output of electrical energy by the energy storage device.

13. The control method according to claim 12, wherein: Acquiring the power requirement information of the power transmission system for the black start includes: receiving the power demand information sent by the scheduling system; The determining, according to the power demand information, the power that the energy storage device needs to output includes: Returning to the dispatching system an indication message confirming that the black start condition is met, and determining the power that the energy storage device needs to output based on the power demand information; The determining, based on at least one of the capacity information and the power requirement information, the power that the energy storage device needs to output and the startup time of the energy storage device includes: sending the capacity information to the scheduling system; The power that the energy storage device needs to output and the start-up time of the energy storage device are determined based on the first electric energy scheduling information returned by the scheduling system.

14. The control method according to claim 13, wherein: When the dispatching system determines, based on the received capacity information, that the capacity of the energy storage device does not meet the power requirement of the black start, the dispatching system determines, based on the capacity information, the power that the energy storage device needs to output; The scheduling system selects other starting power sources based on the power deviation between the power required to be output by the energy storage device and the power requirement of the black start, and determines the starting order of the energy storage device and the other starting power sources; The dispatching system sends the first electric energy dispatching information to the energy storage device; The information carried by the first electric energy scheduling information includes: the power that the energy storage device needs to output and the startup time information.

15. The control method according to claim 12, wherein: Obtaining the power requirement information of the power transmission system for a black start includes: Obtaining the pre-configured power demand information; The determining, based on at least one of the capacity information and the power requirement information, the power that the energy storage device needs to output and the startup time of the energy storage device includes: Determining the power that the energy storage device needs to output and the supplementary power for black start based on the capacity information and the power demand information; Selecting a starting electric energy device based on the supplementary power and determining a starting sequence and starting time for the energy storage device and the selected starting electric energy device; Sending second electric energy scheduling information to the starting electric energy control device; Among them, the information carried by the second electric energy scheduling information includes: the power required to be output and the starting time information corresponding to the selected starting electric energy device; the starting electric energy control device controls the selected starting electric energy device to output electric energy based on the second electric energy scheduling information sent by the energy storage control unit.

16. The control method according to claim 15, wherein determining the startup sequence of the energy storage device and the selected startup electric energy device comprises: The startup sequence is determined based on the power supply types of the energy storage device and the selected startup electric energy device and a startup sequence strategy corresponding to the power supply types.

17. The control method according to claim 11, wherein: The energy storage device comprises a plurality of energy storage module subunits connected in series; The method further comprises: Obtaining the remaining capacity of each energy storage module subunit, and determining the capacity information based on the remaining capacity; The controlling the energy storage device to output electric energy comprises: At least one energy storage module subunit is selected from the plurality of energy storage module subunits and controlled to output electric energy to the power transmission system.

18. The control method according to claim 17, wherein selecting and controlling at least one energy storage module subunit from the plurality of energy storage module subunits to output electric energy to the power transmission system comprises: Based on the remaining capacity and the power that the energy storage device needs to output, an SOC balancing control strategy is used to select and control the at least one energy storage module subunit to output a DC voltage.

19. The control method according to claim 18, wherein: The selecting and controlling the output DC voltage of the at least one energy storage module subunit using the SOC balancing control strategy includes: Sort the subunits of each energy storage module according to the SOC information to obtain the SOC sorting result; Selecting at least one energy storage module subunit according to the SOC sorting result; Based on the reference voltage and / or reference current and the real-time voltage and / or real-time current of the at least one energy storage module subunit, PI control is performed on the at least one energy storage module subunit to output a DC voltage.

20. The control method according to claim 11, wherein the power transmission system comprises a DC bus, a converter, and an AC grid; two ends of the DC bus are respectively connected to the AC grid via the converter; and before providing starting power for a black start to the power transmission system, the method further comprises: Determine whether the AC power grid needs to be black started.

21. The control method according to claim 20, wherein determining whether the AC power grid needs to perform a black start comprises: At least one of the current data of the DC bus, the data of the converter, and the fault status information of the AC power grid is obtained to determine whether the AC power grid needs to be black started.

22. The control method according to any one of claims 11 to 21, further comprising: When the power transmission system operates normally, the energy storage device is controlled to be charged according to the capacity information.

23. An energy storage control unit, comprising: Memory; and a processor coupled to the memory, wherein the processor is configured to execute the method according to any one of claims 11 to 22 based on instructions stored in the memory.

24. A computer-readable storage medium storing computer instructions, wherein the instructions are executed by a processor to perform the method according to any one of claims 11 to 22.

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