WO2024065656A1

WO2024065656A1 - Energy storage system, power transmission system, control method, control unit, and storage medium

Info

Publication number: WO2024065656A1
Application number: PCT/CN2022/123219
Authority: WO
Inventors: 余东旭; 卢艳华; 徐祥祥; 梁李柳元; 梁鹏飞
Original assignee: 宁德时代未来能源(上海)研究院有限公司
Priority date: 2022-09-30
Filing date: 2022-09-30
Publication date: 2024-04-04

Abstract

Embodiments of the present application relate to the technical field of power grid black starts, and provide an energy storage system, a power transmission system, a control method for a black start of the power transmission system, an energy storage control unit, and a storage medium. The energy storage system comprises: an energy storage device and an energy storage control unit. The energy storage control unit is used for controlling, according to capacity information of the energy storage device and power demand information for a black start of a power transmission system when a failure occurs to the power transmission system, the energy storage device to output electrical energy, so as to provide starting electrical energy for the black start to the power transmission system. According to the embodiments of the present application, the electrical energy outputted by the energy storage device can be matched with the power demand of the black start, so that the accuracy of controlling the outputted electrical energy is improved, and smooth completion of the black start can be ensured, thereby improving the success rate and stability of the black start process.

Description

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

Technical Field

The present application relates to the technical field of black start of power grids, 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 technique

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 remain in operation), 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 drive the generator sets without self-starting capabilities in the power grid system to start up, gradually expanding the recovery range of the power grid system and ultimately achieving the recovery of the entire power grid system. In related technologies, the black start of a power grid system is usually provided with starting power 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.

Summary of the invention

The present disclosure provides 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, which can improve the success rate and stability of a black start process.

A first aspect of 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 control the energy storage device to output electric energy in the event of a failure in a power transmission system, based on capacity information of the energy storage device and power demand information of the power transmission system for a black start, so as to provide starting electric energy for a black start to the power transmission system.

The energy storage system disclosed in the present invention provides starting power for black start through an energy storage device, thereby avoiding the self-excitation problem generated when a motor unit is used for black start; the energy storage control unit matches the output power of the energy storage device with the power requirement for black start according to the capacity information of the energy storage device and the power requirement information for black start, thereby ensuring the smooth completion of the black start and improving the success rate and stability of the black start process.

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 to the dispatching system an indication information confirming that the black start is met; 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; based on the power demand information or the first electric energy dispatching information returned by the dispatching system, control the energy storage device to output electric energy.

The energy storage control unit is connected to the dispatching system through the 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 dispatching, and the energy storage control unit controls the energy storage device to output the starting power based on the power dispatching information returned by the dispatching system, and cooperates with other systems to complete the black start, which can ensure the smooth completion of the black start 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.

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 power 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 power scheduling information to the starting power control device, and control the energy storage device to output power based on the power information and time that the energy storage device needs to output.

The energy storage control unit is connected to the starting power control device through the 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 by itself, and cooperates with other starting power devices to complete the black start. When 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.

In some embodiments, the energy storage device includes: a plurality of energy storage module sub-units, the plurality of energy storage module sub-units are connected in series to form the energy storage device, and each energy storage sub-unit 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 sub-unit to determine the capacity information of the energy storage device; and control the energy storage sub-unit to output electrical energy.

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 subunit and independently controlling the output power of each energy storage module subunit, and can provide a variety of power outputs for black start based on power demand, which improves the control accuracy and precision of power output during the black start process and ensures the power demand and power supply of the black start process.

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 ends of each power unit are 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, for returning the remaining capacity of the battery pack upon receiving a capacity acquisition instruction sent by the energy storage control unit; and controlling the state of the power unit and controlling the on and off of the pre-charging circuit upon receiving a control instruction sent by the energy storage control unit.

The energy storage module subunit uses a battery pack as an 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 the pre-charging 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, and has the advantages of good harmonic characteristics and low equivalent switching frequency. It can effectively prevent the battery pack from being overcharged or over-discharged, making the charging and discharging of the battery pack safer and more reliable, and prolonging the service life of the battery pack. The pre-charging 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.

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.

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 to the grid can be reduced, the safety of the energy storage system can be improved, and the service life of the battery pack can be extended.

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 to use the starting resistor for current limiting or short-circuiting the starting resistor.

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 electric energy consumed by the starting resistor.

In some embodiments, the energy storage system also 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.

The current on the DC bus is detected by the fault detection unit, and the data of the converter and the fault status information of the AC power grid are obtained by the DC control and protection unit. This enables the energy storage control unit to respond accurately and quickly when a power 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.

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.

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

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.

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-unit 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-hanging energy storage method in the transmission system has the advantages of a high degree of modularization; it can improve the accuracy of controlling the output electric energy, effectively improve the regulation ability of the output electric energy, and improve the success rate and stability of the black start process.

A third aspect of the present disclosure provides a control method for 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 black start; based on the capacity information and the power requirement information, controlling the energy storage device to output electric energy, and providing starting electric energy for black start to the power transmission system.

The control method for black start of a power transmission system disclosed in the present invention can match the output electric energy of the energy storage device with the power demand of the black start, thereby ensuring the smooth completion of the black start and improving the success rate and stability of the black start process.

In some embodiments, controlling the energy storage device to output electric energy based on the capacity information and the power demand information to provide the power transmission system with starting electric 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 a 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 electric 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 a black start, determining the power that the energy storage device needs to output and the starting 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 electric energy.

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 start-up time of the energy storage device are determined to control the energy storage device to output the starting power for the black start independently or in coordination with other systems, thereby improving the success rate and stability of the black start process.

In some embodiments, obtaining the power requirement information of the power transmission system for a black start includes: receiving the power requirement information sent by a scheduling system; determining the power that the energy storage device needs to output based on the power requirement information includes: returning an indication message confirming that the black start is satisfied 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.

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 electric energy required 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 that the energy storage device needs to output and the start-up time of the energy storage device, so as to control the energy storage device to coordinate with other systems to output the starting electric energy for the black start, which can ensure the smooth completion of the black start 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.

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 of the black start, the dispatching system determines the power that the energy storage device needs to output based on the capacity information; 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 of the black start, and determines the starting 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 the start-up time information.

Through unified power coordination and dispatching by the dispatching system, the starting power that the energy storage device needs to output and the starting sequence are determined, so that the energy storage system and other systems can work together 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.

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 according to 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.

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.

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, it performs unified power coordination and scheduling by itself to determine the starting power that it and the energy storage device need to output and the starting sequence, so that the black start can be successfully completed 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.

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 electric energy includes: 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.

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 control accuracy and precision of power output during the black start process.

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 that the energy storage device needs to output, and using an SOC balancing control strategy to select and control the at least one energy storage module subunit to output a DC voltage.

Selecting the output power of the energy storage module subunit based on the remaining capacity and the power that the energy storage device needs to output can improve the accuracy of controlling the output power, effectively improve the regulation capability of the output power, and improve the success rate and stability of the black start process; using the SOC balancing control strategy to control the output DC bus voltage of the energy storage module subunit 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 output power of the energy storage module subunit more stable, and extend the service life of the battery pack.

In some embodiments, the use of the SOC balancing control strategy to select and control the at least one energy storage module subunit to output a DC voltage includes: sorting 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 a real-time voltage and/or a real-time current of the at least one energy storage module subunit to output a DC bus voltage to the DC bus.

Based on the SOC balancing control strategy and according to the SOC sorting results, the energy storage module sub-units are selected, and the PI control method is used to control the selected energy storage module sub-units to output electric energy to the DC bus. This can improve the accuracy of controlling the output electric energy and improve the success rate and stability of the black start process.

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 also includes: determining whether the AC power grid needs to perform a black start.

By setting up an energy storage system on the DC side of the transmission system and outputting electric energy to the DC bus through the energy storage device, it is possible to provide the transmission system with starting power for a black start. By judging whether a black start is required for the AC power grid, it is possible to respond accurately and quickly when a fault occurs and eliminate the fault quickly.

In some embodiments, the determining whether the AC power grid needs to be black-started includes: obtaining 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 to determine whether the AC power grid needs to be black-started.

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 response can be made when a power grid fault occurs, which enhances the sensitivity of the energy storage system, enables rapid black start and troubleshooting, and can improve the reliability of the transmission system while also improving the management level of the transmission system.

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

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 electric energy, and ensuring the smooth completion of the black start process.

The fourth aspect of the present disclosure provides an energy storage control unit, comprising: a memory; and a processor coupled to the memory, wherein the processor is 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.

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.

A fifth aspect of the present disclosure provides a computer-readable storage medium, which stores computer instructions, and the instructions 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

In order to more clearly illustrate the technical solutions of the embodiments of the present application, the drawings required for use in the embodiments of the present application will be briefly introduced below. 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.

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

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

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

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

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

6A is a sixth system structure schematic diagram of some embodiments of the energy storage system disclosed in the present application; FIG. 6B is a first connection schematic diagram of the control subunit in the energy storage module subunit and other units; FIG. 6C is a second connection schematic diagram of the control subunit in the energy storage module subunit and other units;

FIG7 is a flow chart of some embodiments of a control method for black start of a power transmission system disclosed in the present invention;

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

FIG9 is a schematic diagram of a flow chart of a dispatching system sending electric energy dispatching information in some embodiments of the control method for black start of a power transmission system disclosed in the present invention;

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

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 in the present invention;

FIG. 12 is a schematic diagram of modules in some embodiments of the energy storage control unit disclosed herein.

Detailed ways

The following detailed description and drawings of the embodiments of the present application are used to illustrate the principles of the present application, but cannot be used to limit the scope of the present application, that is, the present application is not limited to the described embodiments.

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).

The present application uses descriptions such as "upper", "lower", "top", "bottom", "front", "back", "inside" and "outside" to indicate directions or positional relationships. This is only for the convenience of describing the present 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 the present application.

In addition, the terms "first", "second", "third", etc. are used for descriptive purposes only and should not be understood as indicating or implying relative importance. "Vertical" is not strictly perpendicular, but is within the tolerance range. "Parallel" is not strictly parallel, but is within the tolerance range. The directional words appearing in the following description are all directions shown in the figures, and are not intended to limit the specific structure of the present application.

In the description of this application, it should also be noted that, unless otherwise clearly specified and limited, the terms "installed", "connected", and "connected" should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral connection; it can be directly connected or indirectly connected through an intermediate medium. For ordinary technicians in this field, the specific meanings of the above terms in this application can be understood according to the specific circumstances.

In some embodiments, as shown in FIG1 , the present disclosure provides an energy storage system, including an energy storage control unit 11 and an energy storage device 12. The energy storage device 12 can be a variety of energy storage devices, and a variety of energy storage methods can be used. For example, the energy storage device 11 includes a battery pack, and the battery pack can be a lithium battery pack, etc., and the battery pack provides electrical energy to the outside. Providing the starting power for black start by the energy storage device 12 can avoid the self-excitation problem generated when the motor unit is used for black start.

The energy storage system may belong to the power transmission system 20, 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 demand information of the power transmission system 20 for black start in a variety of ways. For example, a control subunit is provided in the energy storage device 12, and the capacity information of the energy storage device 12 is sent to the energy storage control unit 11 through the control subunit, or a detection unit for detecting the capacity is provided in the energy storage device 12, and the energy storage control unit 11 obtains the capacity information of the energy storage device 12 detected by the detection unit. The power demand information of the power transmission system 20 for 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 the dispatching system.

The energy storage control unit 11 can use a variety of methods to determine whether the power transmission system 20 has a fault. For example, the energy storage control unit 11 can determine whether the power transmission system 20 has a fault by obtaining information collected by a detection device set for the power transmission system 20, or the energy storage control unit 11 determines that the power transmission system 20 has a fault according to instructions sent by other systems such as a dispatching system. In the case of a fault in the power transmission system 20, the energy storage control unit 11 controls the energy storage device 12 to output electric energy according to the capacity information of the energy storage device 12 and the power demand information of the power transmission system 20 for black start, so as to provide the power transmission system 20 with starting electric energy for black start. The power demand information of the power transmission system 20 for black start includes the electric energy power that the starting power supply needs to output, and the power transmission system 20 can be a variety of systems, such as a flexible direct current transmission system. By controlling the output electric energy of the energy storage device 12 according to the capacity information of the energy storage device and the power demand information for black start by the energy storage control unit 11, the power demand for black start can be accurately matched, the smooth completion of black start is ensured, and the success rate and stability of the black start process are improved.

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 (including power, bus voltage and other information) required for the operation of the power transmission system 20, and control the operation of the power transmission system 20 and perform dispatching decision management. The dispatching system 30 is an independent system relative to the power transmission system 20. The dispatching system 30 can manage the power 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 data can be exchanged. When a fault occurs in the power transmission system 20, the dispatching system 30 determines the power demand information based on the network topology of the power 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.

The energy storage system includes a first communication unit 60, and 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 through an Ethernet network, a bus network, a wireless network, etc. The energy storage control unit 11 itself can also be provided with a communication interface for establishing a communication connection with the dispatching system 30.

The energy storage control unit 11 receives the power demand information sent by the dispatching system 20. If it is determined based on the capacity information and power demand information of the energy storage device 12 that the capacity of the energy storage device 12 can meet the power demand of the black start, then the energy storage control unit 11 returns the indication information confirming that the black start is met to the dispatching system 30, and controls the energy storage device 12 to output electric energy based on the power demand information, and independently provides the starting electric 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 electric energy power that the energy storage device 12 can output is greater than the power demand of the black start, then the energy storage control unit 11 returns the indication information confirming that the black start is met to the dispatching system 30.

If the energy storage control unit 11 determines that the capacity of the energy storage device 12 does not meet the power requirement of 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 that the electric energy power that the energy storage device 12 can output is less than or equal to the power requirement of the black start based on the capacity of the energy storage device 12, the capacity information of the energy storage device 12 is sent to the dispatching system 30.

The dispatch system 30 configures the priority according to the startup capability of each system providing black start power, and determines the startup time of each system, and each system cooperates to complete the startup and recovery of the power grid. The first power dispatch information includes the power and startup time information required to be output by the energy storage system of the present disclosure.

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 operation 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. The energy storage control unit 11 controls the energy storage device 12 to output the starting electric energy based on the first electric energy dispatching information returned by the dispatching system 30, and cooperates with other systems to complete the black start. It can ensure the smooth completion of the black start when 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.

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

The power demand information for the black start, as well as the power information and power supply type of the electric energy that each starting electric energy device 50 can output, can be pre-configured in the energy storage control unit 11. If the energy storage control unit 11 determines that the capacity of the energy storage device 12 can meet the power demand of the black start based on the capacity information and power demand information of the energy storage device 12, it controls the energy storage device 12 to output electric energy based on the power demand information and independently provides the starting electric energy for the black start. For example, if the energy storage control unit 11 determines that the electric energy power that the energy storage device 12 can output is greater than the power demand of the black start based on the capacity of the energy storage device 12, it determines that it can independently provide the starting electric energy for the black start.

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

The energy storage control unit 11 determines the start-up sequence of the energy storage device 12 and the selected start-up electric energy device 50. For example, the energy storage control unit 11 determines the start-up sequence based on the power supply type of the energy storage device 12 and the selected start-up electric energy device 50 and the start-up sequence strategy corresponding to the power supply type. The power supply type includes battery power supply type, thermal power supply type, wind power supply type and photovoltaic power supply type. The start-up sequence strategy includes multiple start-up priorities, for example, the battery power supply has the highest start-up priority, the thermal power supply has a lower start-up priority than the battery power supply, etc. The energy storage control unit 11 determines the start-up time of the energy storage device 12 and the selected start-up electric energy device 50 according to the start-up sequence, and the energy storage device 12 and the selected start-up electric energy device 50 cooperate to complete the start-up recovery of the power grid. The energy storage control unit 11 sends the second electric energy dispatching information to the start-up electric energy control device 40 corresponding to the selected start-up electric energy device 50, and the second electric energy dispatching information includes the power and start-up time information that the start-up electric energy device 50 needs to output. The starting power control device 40 controls the selected starting power device 50 to output power according to the second power scheduling information.

For example, the selected starting power 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 device 50 outputs electric energy and provides power support; or, the selected starting power 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 device 50 to output electric energy synchronously.

The energy storage system includes a second communication unit 70, and 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 through an Ethernet network, a bus network, a wireless network, etc. The energy storage control unit 11 itself can also be provided with a communication interface for establishing a communication connection with the starting power control device 40.

The energy storage control unit 11 is connected to the starting power control device 40 through communication. 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. When the capacity of the energy storage device 12 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.

In some embodiments, as shown in FIG4 , the energy storage device includes energy storage module subunit 121, energy storage module subunit 122, ... energy storage module subunit 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 power transmission system 20 or the first electric energy dispatching information issued by the dispatching system 30, the energy storage control unit 11 selects one or more energy storage module subunits from the energy storage module subunit 121, energy storage module subunit 122, ... energy storage module subunit 12n, and controls the one or more energy storage module subunits to output electric energy to the power transmission system 20. The number n of energy storage module subunits can be configured according to the voltage level and support capacity of the power transmission system.

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, so as to obtain accurate capacity information of the energy storage device and provide a variety of power outputs for black start based on power demand, which can improve the control accuracy and precision of power output during the black start process.

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 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.

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

The energy storage control unit 11 is connected to the dispatching system 30 through the first communication unit 60, and can obtain comprehensive and accurate black start power demand 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, it can accept the unified power coordination and scheduling of the dispatching system 30, and when 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.

The energy storage control unit 11 and the second communication unit 70 may be connected via a bus, a network cable, etc. The second communication unit 70 and the starting power control device 40 may be connected via an Ethernet network, a bus network, a wireless network, etc. When it is determined that the capacity of the energy storage device does not meet the power requirement of the 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.

The energy storage control unit 11 is connected to the starting power control device 40 for communication 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 completes unified power coordination and scheduling, and cooperates with other starting power devices to complete the black start. This ensures that the black start is successfully completed 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.

In some embodiments, the power transmission system may be a variety of power transmission systems, including a DC bus, a converter, and an AC power grid, etc. The DC bus includes a positive DC bus and a negative DC bus, and both ends of the positive DC bus and the negative DC bus are connected to the AC power grid through converters. For example, the power transmission system is a flexible DC transmission system, and the flexible DC transmission system 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 type of 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, not having commutation failures, and being easy to form a multi-terminal DC system. As shown in FIG5 , the flexible DC power transmission system includes a positive DC bus 25, a negative DC bus 26, converters 21, 22, and AC grids 23, 24, etc.; the AC grids 23, 24 can be a variety of AC grids; the converters 21, 22 can be a variety of converters, for example, the converters 21, 22 are VSC (Voltage Sourced Converter) converters, etc. The positive DC bus 25 and the negative DC bus 26 are connected to the AC grids 23, 24 through the converters 21, 22, respectively. A starting power control device and a starting power device can be set in the AC grid 23.

The energy storage module subunit 121, the energy storage module subunit 122 ... the energy storage module subunit 12n, etc. are connected in series or in parallel to form an energy storage device, and the two ends of the energy storage device are respectively connected to the positive DC bus 25 and the negative DC bus 26. The energy storage control unit 11 selects and controls one or more energy storage module subunits of the energy storage module subunit 121, the energy storage module subunit 122 ... the energy storage module subunit 12n to output electric energy to the positive DC bus 25 and the negative DC bus 26 to provide starting electric energy to the AC power grids 23 and 24 based on the remaining capacity of the energy storage module subunit 121, the energy storage module subunit 122 ... the energy storage module subunit 12n, etc. and the power demand information of the power transmission system for black start or the first electric energy dispatching information sent by the dispatching system 30.

The energy storage system disclosed in the present invention is arranged on the DC side of the power transmission system, and the energy storage control unit 11 selects the energy storage module subunit to output electric energy to the DC bus based on the remaining capacity of the energy storage device and the power demand information or electric energy dispatch information of the power transmission system for black start, so as to provide the power transmission system with starting electric energy for black start. Through the energy storage device with modular multi-level cascade structure, the distributed integration of multiple energy storage module subunits can be realized, and the DC direct-hanging energy storage method can be realized in the power transmission system, which has the advantages of high modularity, can improve the accuracy of controlling the output electric energy, and effectively improve the regulation ability of the output electric energy.

In some embodiments, as shown in FIG6A , VSC converters 21 and 22 are respectively arranged at the sending end and the receiving end of the high-voltage flexible direct current transmission system, and the VSC converters 21 and 22 are respectively connected to the AC power grids 23 and 24, and an energy storage device is arranged on the DC side of the high-voltage flexible direct current transmission system, and the energy storage device is composed of energy storage module subunits 121, energy storage module subunits 122...energy storage module subunits 12n connected in series. A current limiting circuit is arranged 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, which are arranged 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 through energy storage reactors 18 and 19. An isolating 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 the connection line between the second end of the energy storage device and the negative DC bus 26. For example, an isolating switch 16 is provided on the connection line between the first end of the energy storage device and the positive DC bus 25. The isolating switch 16 may be an isolating switch, etc., which can isolate the energy storage device from the power grid and form an obvious disconnection point, which is convenient for maintenance and can ensure the safety of personnel.

By setting a direct-mounted energy storage device based on modular multi-level cascading on the DC side of the high-voltage flexible DC transmission system, the capacity of the energy storage device can be increased and the regulating ability of the power grid output power can be improved; by connecting the energy storage device and the

DC bus

25, 26 through the current limiting circuit, energy storage reactor 18, 19, etc., the instantaneous impact current generated when the energy storage device and the

DC bus

25, 26 are switched to the grid can be reduced, which can improve the safety of the energy storage system and extend the service life of the energy storage device.

The current limiting circuit can have a variety of structures. For example, the current limiting circuit includes a starting resistor 171 and a bypass switch 172, and the starting resistor 171 and the bypass switch 172 are connected in parallel. By setting the starting resistor 171, the peak current of charging or discharging can be limited to play a protective role; the energy storage control unit 11 is connected to the bypass switch 172. When the energy storage device is in the initial state of charging and discharging, the energy storage control unit 11 controls the bypass switch 172 to be disconnected. When the energy storage device is in the charging and discharging working 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.

The energy storage module subunit includes a power unit 1221 and an energy storage unit 1222. The energy storage unit 1222 is connected to the power unit 1221, and the energy storage unit 1222 transmits electric energy and is charged through the power unit 1221. The power unit 1221 can adopt a variety of circuit structures. For example, the power unit 1221 includes a rectifier circuit, and the rectifier circuit can be a half-bridge, full-bridge, or quasi-full-bridge rectifier circuit. As shown in FIG6A, the power unit 1221 includes a half-bridge rectifier circuit.

The energy storage unit 1222 can adopt a variety of circuit structures. For example, the energy storage unit 1222 includes an energy storage circuit formed by a battery pack 1225 for storing electric energy and a pre-charging circuit 1224 connected in series. The number of pre-charging circuits 1224 can be one or more, and can be set on one side or both sides of the battery pack 1225. For example, a contactor can also be set in the energy storage circuit. The contactor is a switching component, and the number of contactors is 1 or more. For example, contactors 1223 and contactors 1230 are set in the energy storage circuit. The battery pack 1225 includes a lithium battery pack, etc.

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

When the battery pack 1225 is in the initial stage of charging and discharging, the peak current of charging or discharging can be limited by closing the first switch 1226 and the first switch 1231, and starting the pre-charging resistor 1228 and the pre-charging resistor 1233, so as to play a protective role. When the battery pack 1225 is in the normal working state of charging and discharging, the second switch 1227 and the second switch 1232 are closed to short-circuit the pre-charging resistor 1228 and the pre-charging resistor 1233, so as to reduce the power consumed by starting the pre-charging resistor 1228.

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 a variety of ways. For example, the control subunit 1229 includes one or more processors and a memory, and the memory can be a volatile memory and/or a non-volatile memory for storing one or more computer program instructions. The processor can run the program instructions to realize communication with the energy storage control unit and complete other functions that need to be processed by itself.

The control subunit 1229 is connected to the corresponding battery packs 1225, receives the 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-charging circuit, receives the control instruction sent by the energy storage control unit 11, controls the state of the power unit 1221 and controls the on and off of the pre-charging circuit.

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 state of the power unit 1221 to be in the on state and controls the pre-charge circuit to be on, 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 state of the power unit 1221 to be in the 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.

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. When the control subunit 1229 receives the initial output power control instruction and the normal output power control instruction, the state of the control power unit 1221 is the on state. When the output power control instruction is an 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 a 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.

When the battery pack is in the initial stage of charging and discharging, the energy storage control unit sends an initial output power control instruction to the control subunit, and the control subunit closes the first switch to start the pre-charging resistor, which can limit the peak current of charging or discharging, play a protective role, and improve the safety of the battery pack. When the battery pack is in the normal working state of charging and discharging, the energy storage control unit sends a normal output power control instruction to the control subunit, and the control subunit closes the first switch and the second switch to short-circuit the pre-charging resistor, thereby reducing the power consumed by starting the pre-charging resistor.

Energy storage module subunit 121, energy storage module subunit 122, ... energy storage module subunit 12n, etc. use battery packs as energy sources. The charging and discharging functions of the battery packs can enable the energy storage module subunits to provide stable electric energy for a long time, and have advantages such as good harmonic characteristics and low equivalent switching frequency. By controlling the charging and discharging of the battery pack by the power unit 1221, the stability of the charging and discharging current of the battery pack can be improved, and the battery pack can be effectively prevented from being overcharged or over-discharged, making the charging and discharging of the battery pack safer and more reliable, and improving the service life of the battery pack. By setting a pre-charging circuit, the energy storage unit 1222 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.

A variety of detection units can be used for fault detection. The fault detection units 13 and 14 are respectively arranged on the positive DC bus 25 and the negative DC bus 26. The number of fault detection units can also be one, which is arranged on the positive DC bus 25 or the negative DC bus 26. The fault detection units 13 and 14 can use a variety of detection devices to detect the current, voltage data, etc. of the positive DC bus 25 and/or the negative DC bus 26.

The DC control and protection unit 15 is connected to the VSC converters 21 and 22. The DC control and protection unit 15 can use a variety of detection devices to obtain the data of the VSC converters 21 and 22 and the fault status information of the AC power grids 23 and 24; the data of the VSC converters 21 and 22 include: data such as the converter node voltage and the corresponding output or input power; the fault status information includes the grid fault information sent by the management system in the AC power grids 23 and 24. The energy storage control unit 11 can be connected to the starting power control device through the DC control and protection unit 15 and perform data exchange. Only a fault detection unit or a DC control and protection unit can be set, or both a fault detection unit and a DC control and protection unit can be set.

The fault detection units 13 and 14 detect the current data (or voltage data) on the positive DC bus 25 and the negative DC bus 26 in real time, and can send them to the energy storage control unit 11 through communication methods such as bus, optical fiber and wireless communication. The DC control and protection unit 15 can obtain the data of the VSC converters 21 and 22 and the fault status information of the AC power grid 23 and 24 in real time, and can send them to the energy storage control unit 11 through communication methods such as bus, optical fiber and wireless communication. The energy storage control unit 11 determines whether the operation of the AC power grid 23 and 24 is normal and whether a black start is required based on one or more of the current data, the converter data and the fault status information.

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, 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, 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.

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 eliminate the fault, thereby improving the reliability of the power transmission system and improving the management level of the power transmission system.

When the energy storage control unit 11 determines that a black start is required, the operation mode is adjusted to the black start operation mode. The energy storage control unit 11 determines the remaining capacity of the energy storage module subunit 121, the energy storage module subunit 122... the energy storage module subunit 12n by acquiring the remaining SOC (State of Charge) information of the battery cells in the energy storage module subunit 121, the energy storage module subunit 122... the energy storage module subunit 12n; the energy storage control unit 11 obtains the capacity information of the energy storage device based on the remaining capacity of all the energy storage module subunits.

The energy storage control unit 11 sends a power request to the dispatching system 30, and receives the power demand information of the power transmission system for black start sent by the dispatching system. If the energy storage control unit 11 determines that the capacity of the energy storage device meets the power demand of the black start and the energy storage device has the ability to start independently, it returns an indication message confirming that the black start is met to the dispatching system 30. Based on the remaining capacity of the storage device and the power demand information of the power transmission system for black start, the energy storage control unit 11 selects and controls one or more energy storage module subunits 121, energy storage module subunit 122...energy storage module subunit 12n to output electric energy to the positive DC bus 25 and the negative DC bus 26.

If the energy storage control unit 11 determines that the capacity of the energy storage device does not meet the power requirement of the black start and the energy storage device does not have the independent starting capability, the capacity information of the energy storage device is sent to the dispatching system 30, so that the dispatching system 30 determines the power that the energy storage device needs to output according to the capacity information of the energy storage device, and 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 of the black start. The other starting power sources can be units in the wind power grid, the new energy grid, etc., and determine the starting sequence of the energy storage device and other starting power sources. For example, the dispatching system 30 configures other starting power sources that are closest to the power deviation by redistributing the power required for the black start, and determines the starting sequence.

The dispatching system 30 sends the first electric energy dispatching information to the energy storage control unit 11. The information carried by the first electric energy dispatching information includes the power that the energy storage device needs to output and the startup time information. For example, the power that the energy storage device needs to output is 100w, and the startup time information is the time when the energy storage device starts and outputs electric energy. The dispatching system 30 can control the energy storage system of the present disclosure and other starting power sources to cooperate in a predetermined priority order, input electric energy in sequence, and provide the transmission system with starting electric energy for black start.

The energy storage control unit 11 selects and controls one or more energy storage module subunits among the 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 dispatching information sent by the dispatching system 30.

As shown in FIG6A , the energy storage control unit 11 selects and controls one or more energy storage module subunits among the energy storage module subunits 121, 122, ... 12n to output a DC bus voltage to the positive DC bus 25 and the negative DC bus 26 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, thereby driving the VSC converters 21, 22 and the equipment in the AC power grids 23, 24 to start and recover.

For example, the energy storage control unit 11 can determine the number and position of the energy storage module subunits that need to output electric energy 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, and adopt a variety of SOC balancing control strategies, and control the selected energy storage module subunits to output the DC bus voltage to the DC bus, which can maintain the DC bus voltage stable, and through power regulation, the SOC balance of the battery cells of different energy storage module subunits can be guaranteed. The energy storage control unit 11 controls one or more energy storage module subunits to output the DC bus voltage to the DC bus, driving the VSC converters 21 and 22 to start in sequence, and then the electric energy output by the one or more energy storage module subunits drives the AC power grids 23 and 24 through the VSC converters 21 and 22 to complete the power grid startup recovery.

By using the SOC balancing control strategy through the energy storage control unit 11 to control the DC bus voltage output by the energy storage module sub-unit, the stability of the DC bus voltage can be maintained, the SOC convergence of the battery packs of each energy storage module sub-unit can be adjusted, 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.

When the power transmission system is operating normally, the energy storage control unit 111 controls the energy storage device to charge according to the capacity information of the energy storage device. If the energy storage control unit 111 determines that the AC power grid 23, 24 is operating normally according to one or more of the current or voltage data on the DC bus, the data of the converter and the fault status information, the energy storage device is configured to be in a charging state, and a variety of SOC balancing control strategies can be used for charging control.

The energy storage control unit 11 controls the energy storage device to charge when it is suitable for charging, 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.

The energy storage system disclosed in the present invention can solve the problem of not being able to successfully complete a black start when using hydropower units, wind power units, 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.

In some embodiments, the present disclosure provides a power transmission system, including the energy storage system in any of the above embodiments. The power transmission system may be a flexible direct current transmission system or the like. The power transmission system of the present disclosure has the advantages of the energy storage system in any of the above embodiments.

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 chart of some embodiments of the control method for a black start of a power transmission system of the present disclosure, as shown in FIG7:

Step 701: when a power transmission system fails, obtain capacity information of an energy storage device and power demand information of the power transmission system for a black start.

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 the transmission system with starting electric energy for performing a black start.

The energy storage control unit can be implemented in a variety of ways to implement the control method for black start of a power transmission system in 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 forms of processing units with data processing capabilities and/or instruction execution capabilities, and the memory can be a volatile memory and/or a non-volatile memory to store one or more computer program instructions, and the processor can run the program instructions to implement the control method for black start of a power transmission system in various embodiments of the present disclosure or other desired functions.

The control method for black start of a power transmission system disclosed in the present invention controls the output electric energy of the energy storage device according to the capacity information of the energy storage device and the power demand information for the black start, can accurately match the power demand for the black start, ensure the smooth completion of the black start, and improve the success rate and stability of the black start process.

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 demand of the 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 to output electric 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 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 based on at least one of the capacity information and the power demand information to control the energy storage device to output electric energy.

By using the energy storage control unit to determine the power that the energy storage device needs to output or the power that the energy storage device needs to output and the start-up 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, the energy storage device is controlled to output the starting power to complete the black start independently or in coordination with other systems, thereby improving the success rate and stability of the black start process.

In some embodiments, the energy storage control unit is connected to the dispatching system in communication. 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 in the present invention, as shown in FIG8:

Step 801, receiving power demand information sent by the scheduling system.

Step 802 , based on the capacity information and the power demand information, determine whether the capacity of the energy storage device meets the power demand of the black start, if yes, proceed to step 803 , if no, proceed to step 804 .

Step 803, returning indication information confirming that the black start conditions are met to the dispatching system, and controlling the energy storage device to output electric energy based on the power demand information.

Step 804, sending capacity information to the dispatching system; and controlling the energy storage device to output electric energy based on the first electric energy dispatching information returned by the dispatching system.

The dispatching system is provided with a functional device for communicating with the energy storage control unit and completing other processing functions. This functional device can be implemented in a variety of ways. For example, the functional device 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 run the program instructions to achieve communication with the energy storage control unit and complete other functions that need to be processed by itself.

By obtaining the power demand information of the transmission system for black start from the dispatching system, comprehensive and accurate power demand information can be obtained; the black start can be successfully completed 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.

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

Step 901: When it is determined according to 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 according to the capacity information.

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.

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: power to be output and start-up time information.

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 in the present invention, as shown in FIG10 :

Step 1001, based on the capacity information and the power demand information, determine whether the capacity of the energy storage device meets the power demand of the black start, if yes, proceed to step 1002, if no, proceed to step 1003.

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

Step 1003: determine the power that the energy storage device needs to output and the supplementary power for the black start.

Step 1004 , selecting a starting electric energy device based on the supplemental power and determining a starting sequence of the energy storage device and the selected starting electric energy device.

Step 1005: Send second power dispatch information to the starting power control device corresponding to the selected starting power device. The second power dispatch information carries information including the power required to be output by the starting power device and the starting time information.

The kinetic energy control system is provided with a functional device for communicating with the energy storage control unit and completing other processing functions. This functional device can be implemented in a variety of ways. For example, the functional device includes one or more processors and a memory, and the memory can be a volatile memory and/or a non-volatile memory for storing one or more computer program instructions. The processor can run the program instructions to communicate with the energy storage control unit and complete other functions that need to be processed by itself.

By performing unified power coordination and scheduling by the energy storage control unit itself, the black start can be successfully completed 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.

In some embodiments, the energy storage device includes a plurality of 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:

Step 1101 , based on the remaining capacity and the power demand information of the power transmission system for black start or the first power dispatching 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.

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 control accuracy and precision of power output during the black start process.

In some embodiments, the power transmission system includes a flexible direct current power transmission system; the flexible direct current power transmission system includes a direct current bus, a converter and an alternating current grid; the two ends of the direct current bus are respectively connected through a converter and an alternating current grid; 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 direct current bus.

There are many methods for selecting and controlling the energy storage module subunits to output electric 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 electric energy scheduling information, at least one energy storage module subunit is selected and controlled to output electric energy to the DC bus to provide starting electric energy to the AC power grid. There are many methods for controlling the energy storage module subunits to output electric 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 electric energy 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 electric 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.

By using the SOC balancing control strategy to select and control the output DC bus voltage of the energy storage module sub-unit, 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.

In some embodiments, the SOC balance control strategy includes a sorting selection strategy, etc. Sorting is performed according to the SOC information of each energy storage module subunit to obtain an SOC sorting result; using the SOC balance control strategy and based on the SOC sorting result, at least one energy storage module subunit is selected. For example, the SOC information of each energy storage module subunit is sorted from high to low, and the sorting selection strategy is used to select at least one energy storage module subunit ranked at the top of the SOC sorting result to meet the power demand of the power transmission system for black start or the requirements of power scheduling.

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 the reference current and the real-time voltage and/or the real-time current of at least one energy storage module sub-unit, so as to output the DC bus voltage to the DC bus.

In some embodiments, the energy storage device is connected to the DC bus through an isolation switch device, a current limiting circuit, and an energy storage reactor; the current limiting circuit includes a starting resistor and a bypass switch, and the starting resistor and the bypass switch are connected in parallel. When the energy storage device is in a charge and discharge working state, the bypass switch is controlled to close to short-circuit the starting resistor. By closing the bypass switch when the energy storage device is in a charge and discharge working state to short-circuit the starting resistor, the electric energy consumed by the starting resistor can be reduced.

The energy storage system includes a fault detection unit and a DC control and protection unit. The fault detection unit is arranged on the DC bus to detect the current data (or voltage data) of the DC bus; the DC control and protection unit is connected to the converter to obtain the data of the converter and the fault status information of the AC power grid. It is judged whether the AC power grid needs to be black-started based on at least one of the current data, the data of the converter and the fault status information. 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. When a fault occurs in the power grid, an accurate and rapid response can be made, and a black-start can be performed and the fault can be eliminated in time, thereby improving the reliability of the power transmission system.

When the power transmission system is operating normally, the energy storage device is controlled to charge according to the capacity information, which 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.

In some embodiments, the present disclosure provides an energy storage control unit. FIG12 is a module schematic diagram of an embodiment of an energy storage control unit according to the present disclosure. As shown in FIG12, the energy storage control unit may include a memory 1201, a processor 1202, a communication interface 1203, and a bus 1204. The memory 1201 is used to store instructions, the processor 1202 is coupled to the memory 1201, and the processor 1202 is configured to execute the control method for black start of the power transmission system in any of the above embodiments based on the instructions stored in the memory 1201.

The memory 1201 may be a high-speed RAM memory, a non-volatile memory, etc. The memory 1201 may also be a memory array. The memory 1201 may also be divided into blocks, and the blocks may be combined into virtual volumes according to certain rules. The processor 1202 may be a central processing unit CPU, or an application specific integrated circuit ASIC (Application Specific Integrated Circuit), or one or more integrated circuits configured to implement the control method for black start of a power transmission system disclosed in the present invention.

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

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 include, for example, but is not limited to, a system, device or device of electricity, magnetism, light, electromagnetic, infrared, or semiconductor, or any combination of the above. 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 of the above.

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 produce a device for implementing the functions specified in one process or multiple processes in the flowchart and/or one box or multiple boxes in the block diagram.

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 work in a specific manner, so that the instructions stored in the computer-readable memory produce a manufactured 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.

The method and system of the present disclosure may be implemented in many ways. For example, the method and system 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 specifically stated. In addition, in some embodiments, the present disclosure may also be implemented as a program recorded in a recording medium, which includes machine-readable instructions for implementing the method according to the present disclosure. Therefore, the present disclosure also covers a recording medium storing a program for executing the method according to the present disclosure.

Although the present application has been described with reference to preferred embodiments, various modifications may be made thereto and parts thereof may be replaced with equivalents without departing from the scope of the present application. In particular, the various technical features mentioned 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 includes all technical solutions falling within the scope of the claims.

Claims

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 failure in the power transmission system, based on capacity information of the energy storage device and power demand information of the power transmission system for a black start, so as to provide the power transmission system with starting electric energy for a black start.
The energy storage system according to claim 1, comprising: a first communication unit;

The energy storage control unit establishes a communication connection with the dispatching system through the first communication unit;

The energy storage control unit is used to receive the power demand information sent by the dispatching system; when it is determined that the capacity of the energy storage device meets the power demand of the black start, return to the dispatching system an indication information confirming that the black start is met; 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.
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 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 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.
The energy storage system according to claim 1, wherein:

The energy storage device comprises a plurality of energy storage module sub-units; the plurality of energy storage module sub-units are connected in series to form the energy storage device, and each energy storage sub-unit 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.
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 connecting a battery pack and a pre-charge circuit in series, and 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-charging 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 control the state of the power unit and control the on and off of the pre-charging circuit upon receiving a control instruction sent by the energy storage control unit.
The energy storage system according to claim 1, comprising: a current limiting circuit and an energy storage reactance;

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.
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 a starting resistor for current limiting or to short-circuit the starting resistor.
The energy storage system according to claim 1, further comprising:

a fault detection unit, arranged on the 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, for acquiring 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.
A power transmission system, comprising:

An energy storage system as claimed in any one of claims 1 to 8.
The power transmission system according to claim 9, wherein the power transmission system comprises: a DC bus, a converter and an AC grid; the DC bus comprises: 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 grid through the converter;

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.
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 black start to the power transmission system.
The control method according to claim 11, wherein the controlling the energy storage device to output electric energy based on the capacity information and the power demand information to provide the power transmission system with starting electric energy for a black start 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, the power that the energy storage device needs to output is determined 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 energy storage device to output electrical energy.
The control method according to claim 12, wherein obtaining the power requirement information of the power transmission system for black start comprises:

Receiving the power demand information sent by the dispatching system;

The step of determining the power that the energy storage device needs to output according to the power demand information 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 the power that the energy storage device needs to output and the start-up time of the energy storage device according to at least one of the capacity information and the power demand information 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.
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 dispatching 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;

Among them, the information carried by the first electric energy scheduling information includes: the power that the energy storage device needs to output and the start time information.
The control method according to claim 12, wherein obtaining the power demand information of the power transmission system for black start comprises:

Acquiring the pre-configured power demand information;

The determining the power that the energy storage device needs to output and the start-up time of the energy storage device according to at least one of the capacity information and the power demand information includes:

Determine 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 of the energy storage device and the selected starting electric energy device;

Sending second electric energy dispatching information to the starting electric energy control device;

Among them, the information carried by the second power scheduling information includes: the power required to be output and the starting time information corresponding to the selected starting power device; the starting power control device controls the selected starting power device to output power based on the second power scheduling information sent by the energy storage control unit.
The control method according to claim 15, wherein determining the start-up sequence of the energy storage device and the selected start-up electric energy device comprises:

The startup sequence is determined based on the power supply type of the energy storage device and the selected startup electric energy device and a startup sequence strategy corresponding to the power supply type.
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:

Acquire the remaining capacity of each energy storage module subunit, and determine 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.
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.
The control method according to claim 18, wherein the step of selecting and controlling the output DC voltage of the at least one energy storage module subunit using the SOC balancing control strategy comprises:

Sort the SOC information of each energy storage module subunit to obtain the SOC sorting result;

According to the SOC ranking result, selecting at least one energy storage module subunit;

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.
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 through the converter; before providing the power transmission system with starting power for a black start, the method further comprises:

Determine whether the AC power grid needs to be black started.
The control method according to claim 20, wherein the 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.
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.
An energy storage control unit, comprising:

A memory; and a processor coupled to the memory, the processor being configured to execute the method according to any one of claims 11-22 based on instructions stored in the memory.
A computer-readable storage medium stores computer instructions, wherein the instructions are executed by a processor according to any one of claims 11 to 22.