Grid-connected circuit, grid-connected confluence circuit, energy storage grid-connected cabinet, energy storage confluence grid-connected cabinet and energy storage system

Abstract

The utility model discloses a grid-connected circuit, a grid-connected confluence circuit, an energy storage grid-connected cabinet, an energy storage confluence grid-connected cabinet and an energy storage system. The grid-connected circuit comprises a first auxiliary power supply sub-circuit and a plurality of groups of grid-connected branches, the first auxiliary power supply sub-circuit is electrically connected with the plurality of groups of grid-connected branches, and the first auxiliary power supply sub-circuit is configured to provide auxiliary power supply and overvoltage protection for the grid-connected branches; the plurality of groups of grid-connected branches are connected in parallel, are connected with a matched confluence circuit, and are configured to be electrically connected with corresponding external transformer loops respectively; and electrical interlocking is arranged among the plurality of groups of grid-connected branches, so that only one group of grid-connected branches can operate at the same time. According to the grid-connected circuit provided by the invention, grid connection can be carried out under multiple groups of transformers, charging and discharging control is carried out according to the electrical attributes of the transformers and the overall condition and electrical attributes of the energy storage system, peak-valley arbitrage is realized in the electricity consumption change process, and meanwhile, the condition of simultaneous closing is avoided by adopting an electrical interlocking device.

Description

Technical Field

[0001] This application relates to the field of energy storage system technology, specifically to a grid-connected circuit, a grid-connected bus circuit, an energy storage grid-connected cabinet, an energy storage bus grid-connected cabinet, and an energy storage system. Background Technology

[0002] Currently, in related technologies, the charge capacity of a single energy storage cabinet is mainly 100kW / 200kWh. These cabinets are widely used in various scenarios, with a grid-connected capacity of no more than 1MW under 400V voltage. In application, these energy storage cabinets are typically connected to one or more grid-connected cabinets through a single transformer, and then the grid-connected cabinets are connected to the energy storage cabinets for charging and discharging. Although there is a one-to-one or one-to-many relationship between the transformer and the grid-connected cabinets, the entire energy storage system only charges and discharges through a single transformer. For power-consuming units such as factories, the load rate is relatively high, making peak-valley arbitrage impossible. Furthermore, in most application scenarios, the number of grid-connected cabinets is large, occupying significant space. Utility Model Content

[0003] This application provides a grid-connected circuit, a grid-connected bus circuit, an energy storage grid-connected cabinet, an energy storage bus grid-connected cabinet, and an energy storage system.

[0004] The grid-connected circuit involved in the embodiments of this application includes a first auxiliary power supply circuit and multiple sets of grid-connected sub-circuits. The first auxiliary power supply circuit is configured to provide auxiliary power supply and overvoltage protection to the grid-connected sub-circuits. The multiple sets of grid-connected sub-circuits are connected in parallel and configured to be connected to a matching bus circuit. The multiple sets of grid-connected sub-circuits are configured to be connected to corresponding external transformer circuits respectively.

[0005] Electrical interlocks are provided between the multiple sets of grid-connected sub-circuits to ensure that only one set of grid-connected sub-circuits is in operation at any given time, or to ensure that none of the multiple sets of grid-connected branches are in operation at any given time.

[0006] In some implementations, the grid-connected branch includes a disconnecting switch module and a circuit breaker module, the disconnecting switch module being configured to protect the safety of maintenance personnel during maintenance of the grid-connected circuit;

[0007] The electrical interlock is provided in the circuit breaker module, which is configured to control the on / off state of the grid-connected branch.

[0008] In some embodiments, the grid-connected sub-circuit further includes a first current transformer module and a circuit monitoring module. The first current transformer module is connected in series between the disconnecting switch module and the circuit breaker module, and the circuit monitoring module is configured to monitor the circuit parameters of the first current transformer module.

[0009] In some embodiments, the first current transformer module includes a current transformer, and the circuit monitoring module includes a data acquisition and metering submodule and a power quality monitoring submodule.

[0010] The acquisition and metering submodule is connected to the first current transformer. The acquisition and metering submodule includes a locally powered acquisition unit and a metering electricity meter. The acquisition and metering submodule is configured to acquire the current at the first current transformer and the active and reactive power corresponding to the current over a period of time.

[0011] The power quality monitoring submodule is connected to the second current transformer, and the power quality monitoring submodule is configured to acquire power quality information corresponding to the current introduced by the grid-connected subcircuit.

[0012] In some embodiments, the grid-connected subcircuit further includes an anti-islanding protection module connected to a third current transformer. The anti-islanding protection module is configured to control the circuit breaker module to disconnect when the voltage or frequency at the third current transformer fluctuates and the amplitude of the fluctuation exceeds a preset value.

[0013] In some implementations, the first auxiliary power supply circuit includes a socket, a surge protection device, and multiple miniature circuit breakers;

[0014] The miniature circuit breaker is connected between the socket and the grid-connected sub-circuit, or between the surge protection device and the grid-connected sub-circuit;

[0015] The socket is connected to the external power grid, and the surge protection device is grounded.

[0016] Thus, the grid-connected circuit provided in this application can be connected to the grid under multiple transformers. Based on the electrical properties of the transformers and the overall situation and electrical properties of the energy storage system, charging and discharging control is performed to reduce the transformer load rate. During the process of power consumption change, peak-valley arbitrage is achieved through charging and discharging control. At the same time, an electrical interlocking device is used to ensure that multiple circuit breakers will not close at the same time, thereby eliminating the hidden danger of transformers with different voltages operating in parallel at the same time and improving the safety of the energy storage system.

[0017] The grid-connected bus circuit involved in the embodiments of this application includes a grid-connected sub-circuit and a bus sub-circuit; the grid-connected sub-circuit includes the above-mentioned grid-connected circuit; the bus sub-circuit includes multiple control switches and corresponding energy storage cabinets, and each control switch is connected to a unique corresponding energy storage cabinet.

[0018] In some embodiments, the bus circuit further includes a second current transformer module and a second auxiliary power supply circuit. The second current transformer module includes a circuit breaker, one or more current transformers connected in series, and a current meter connected to the current transformers. The second auxiliary power supply circuit includes a socket, a surge protection device, and multiple miniature circuit breakers. The miniature circuit breakers are connected between the socket and the second current transformer module. The socket is connected to an external power grid, and the surge protection device is grounded.

[0019] Thus, the grid-connected bus circuit provided in this application can be connected to the grid under multiple transformers. Based on the electrical properties of the transformers and the overall situation and electrical properties of the energy storage system, charging and discharging control is performed to reduce the transformer load rate. Peak-valley arbitrage is achieved through charging and discharging control during changes in electricity consumption. Simultaneously, electrical interlocking devices ensure that multiple circuit breakers do not close simultaneously, thereby eliminating the potential danger of transformers with different voltages operating in parallel and improving the safety of the energy storage system. Furthermore, merging the grid-connected sub-circuit and the bus circuit into a single grid-connected bus circuit allows the grid-connected and bus functions to be combined into one or two distribution cabinets, further saving space and materials compared to solutions requiring three or more distribution cabinets to handle both grid-connected and bus functions.

[0020] The energy storage grid-connected cabinet in this application includes the above-mentioned grid-connected circuit and auxiliary devices including copper busbars, cabinets, and terminal blocks.

[0021] The energy storage combiner grid-connected cabinet in this application includes the grid-connected circuit described above, the grid-connected combiner circuit described above, and auxiliary devices including copper busbars, cabinets, and terminal blocks.

[0022] The energy storage system in this application includes the grid-connected circuit described above, and the energy storage system also includes multiple energy storage cabinets and an energy management system.

[0023] The energy storage system in this application includes the grid-connected bus circuit described above, and the energy storage system also includes multiple energy storage cabinets and an energy management system.

[0024] Additional aspects and advantages of embodiments of this application will be set forth in part in the description which follows, and in part will be obvious from the description, or may be learned by practice of embodiments of this application. Attached Figure Description

[0025] The above and / or additional aspects and advantages of this application will become apparent and readily understood from the following description of the embodiments taken in conjunction with the accompanying drawings, wherein:

[0026] Figure 1 This is a schematic diagram of the circuit module of the grid-connected circuit in the embodiment of this application;

[0027] Figure 2 This is a simplified circuit diagram of the grid-connected circuit in the embodiments of this application;

[0028] Figure 3 This is a schematic diagram of the circuit module of the grid-connected bus circuit in the embodiment of this application;

[0029] Figure 4 This is a simplified circuit diagram of the grid-connected bus circuit in the embodiments of this application.

[0030] The circuit includes: 01, external transformer circuit; 02, external transformer circuit; 03, bus circuit; 10, grid-connected circuit; 111, first grid-connected sub-circuit; 112, second grid-connected sub-circuit; 12, first auxiliary power supply circuit; T1, first external transformer; T2, second external transformer; K1, first incoming circuit breaker; K2, second incoming circuit breaker; QS1, first disconnecting switch; CT11, current transformer 1#; CT12, current transformer 2#; CT13, current transformer 3#; 1QF, first circuit breaker; QS2, second disconnecting switch; CT21, current transformer 4#; CT22, current transformer 5#; CT23, current transformer 6#; 2QF, second circuit breaker; 1111, circuit monitoring module; 11111, data acquisition and metering sub-module; 11112. Power quality monitoring submodule; 1112, anti-islanding protection module; 1121, circuit monitoring module; 11211, data acquisition and metering submodule; 11212, power quality monitoring submodule; 1122, anti-islanding protection module; MCCB1, miniature circuit breaker 1#; MCCB2, miniature circuit breaker 2#; MCCB3, miniature circuit breaker 3#; SPD1, surge protection device 1#; QF1, control switch 1#; QF2, control switch 2#; QFn-1, control switch (n-1)#; QFn, control switch n#; MCCB4, miniature circuit breaker 4#; MCCB5, miniature circuit breaker 5#; MCCB6, miniature circuit breaker 6#; SPD2, surge protection device 1#; QF, bus circuit breaker; 21, second current transformer module; CT, current transformer 7#. Detailed Implementation

[0031] The embodiments of this application are described in detail below. Examples of the embodiments are shown in the accompanying drawings, wherein the same or similar reference numerals denote the same or similar elements or elements having the same or similar functions throughout. The embodiments described below with reference to the accompanying drawings are exemplary and are only used to explain the embodiments of this application, and should not be construed as limiting the embodiments of this application.

[0032] The grid-connected circuit in this application includes a first auxiliary power supply circuit and multiple sets of grid-connected branches. The first auxiliary power supply circuit is configured to provide auxiliary power supply and overvoltage protection to the grid-connected branches. The multiple sets of grid-connected branches are connected in parallel and are configured to be connected to the matching bus circuit. The multiple sets of grid-connected branches are configured to be connected to the corresponding external transformer circuits respectively.

[0033] Electrical interlocks are installed between multiple sets of grid-connected branches to ensure that only one set of grid-connected branches is in operation at any given time, or that none of the multiple sets of grid-connected branches are in operation at any given time.

[0034] Please refer to the details. Figure 1 , Figure 1 Taking the setting of two sets of grid-connected branches as an example, the grid-connected circuit 10 in this application embodiment is illustrated. Exemplarily, the power distribution bus in the external transformer circuit 01 and external transformer circuit 02 is a 400V incoming line. External transformer circuit 01 is connected to grid-connected branch 111, and external transformer circuit 02 is connected to grid-connected branch 112. The first grid-connected branch 111 and the second grid-connected branch 112 are connected in parallel and are both connected to the bus circuit 03. At the same time, the first auxiliary power supply circuit 12 is also connected to the bus circuit 03 along with the above two. The first auxiliary power supply circuit 12 has two main functions: firstly, it connects to the external circuit and provides auxiliary power to the components in the first grid-connected branch 111 and the second grid-connected branch 112 that require partial power supply through external power supply; secondly, it provides overvoltage protection for the grid-connected circuit 10 through connection with other external components or ground, preventing the grid-connected circuit 10 from being burned out when there are drastic voltage changes in the external transformer circuit.

[0035] Furthermore, an electrical interlock is provided between the first grid-connected branch 111 and the second grid-connected branch 112. This electrical interlock is generally implemented through an electrical interlocking device controlled by the energy management system (EMS) of the energy storage system. Based on the charging and discharging strategies of the energy storage system at different times, the EMS will issue tripping commands to control the first grid-connected branch 111 to be connected and the second grid-connected branch 112 to be disconnected, or vice versa. Simultaneously, in conjunction with the aforementioned electrical interlocking device, it ensures that when one branch is connected and operating, the other branch is always disconnected, preventing simultaneous operation and thus guaranteeing the correct execution of the charging and discharging strategy. The above example includes two sets of grid-connected branches; the same principle applies to grid-connected circuits with three or more sets of branches, where electrical interlocks are provided between each branch to ensure that only one branch is connected and operating at any given time.

[0036] Furthermore, when grid-connected circuit 10 requires maintenance, all of the aforementioned grid-connected branches must be shut down to ensure the safety of maintenance personnel. Therefore, exemplarily, the aforementioned electrical interlocking device can also ensure that all grid-connected branches are simultaneously disconnected and inoperable, thereby protecting the safety of maintenance personnel.

[0037] In some implementations, the grid-connected branch includes a disconnect switch module and a circuit breaker module, wherein the disconnect switch module is configured to protect the safety of maintenance personnel during grid-connected circuit maintenance.

[0038] Electrical interlocking devices are installed in the circuit breaker module, which is configured to control the on / off state of the grid-connected branch.

[0039] For details, please refer to the following: Figure 2 , Figure 2 exist Figure 1 The circuit structure of the grid-connected circuit is illustrated below. The grid-connected circuit 10 includes a first grid-connected branch 111 and a second grid-connected branch 112. Each grid-connected branch includes a disconnecting switch module and a circuit breaker module. In the first grid-connected branch 111, the disconnecting switch module is a first disconnecting switch QS1, and the circuit breaker module is a first circuit breaker 1QF. In the second grid-connected branch 112, the disconnecting switch module is a second disconnecting switch QS2, and the circuit breaker module is a second circuit breaker 2QF. Furthermore, the external transformer circuit 01 connected to the first grid-connected branch 111 includes a first external transformer T1 and a corresponding incoming circuit breaker K1. The external transformer circuit 02 connected to the second grid-connected branch 112 includes a second external transformer T2 and a corresponding incoming circuit breaker K2.

[0040] Based on the circuit structure described above, the operation mode of the grid-connected circuit 10 will be explained by way of example below:

[0041] First, with the first disconnecting switch QS1 and the second disconnecting switch QS2 closed, when the grid-connected circuit 10 starts, the energy management system (EMS) controls the opening and closing times of 1QF and 2QF according to the charging and discharging strategies of the energy storage system at different times. The external transformers connected during the charging and discharging of the grid-connected circuit 10 are determined based on the installed capacity of the energy storage system, the capacity of the first external transformer T1 and the second external transformer T2, the load factor, and the actual electrical load.

[0042] When the energy storage system needs to be charged during off-peak hours or normal periods, the external transformer with the larger difference in capacity between T1 and T2 and the installed capacity of the energy storage system is selected for charging, based on the load rates of T1 and T2. If it is ultimately determined that the energy storage system will be charged through the second external transformer T2, the EMS first issues a trip command to disconnect 1QF. After receiving the trip position signal of 1QF, it then issues a closing command to close 2QF. When the load rates of T1 and T2 change during charging, causing a change in the above-mentioned charging selection conditions, the EMS can switch the tripping status of 2QF and 1QF according to the actual situation to achieve the switching of external transformers during charging. For example, to ensure safe use, the load rate of the external transformer should be controlled within the range of no more than 90% to 95% during charging.

[0043] When the energy storage system needs to discharge during peak or high-peak periods, the grid-connected circuit 10 selects to prioritize discharging the external transformer with the larger actual load based on the actual load of T1 and T2. If it is ultimately determined to discharge the first external transformer T1, the EMS first issues a tripping command to disconnect 2QF. After receiving the tripping position signal of 2QF, it then issues a closing command to close 1QF. When the actual load of T1 and T2 changes during the discharge process, causing the above-mentioned discharge selection conditions to change, the EMS can switch the tripping and closing states of 2QF and 1QF according to the actual situation to realize the switching of external transformers during discharge. During discharge, the load rate of external transformers should be controlled within the range of no more than 90% to 95%.

[0044] Based on the above electrical interlocking, an electrical interlocking device is set between 1QF and 2QF, which can connect the 1QF's breaker auxiliary node in series with the 2QF's closing circuit, and at the same time connect the 2QF's breaker auxiliary node in series with the 1QF's closing circuit, ensuring that the two circuit breakers 1QF and 2QF cannot be closed at the same time, so as to prevent T1 and T2 from operating in parallel.

[0045] Furthermore, when the energy storage system requires maintenance, to ensure the safety of all components and maintenance personnel, and in accordance with electrical safety regulations, the first circuit breaker 1QF and the second circuit breaker 2QF should be disconnected first, followed by the first disconnecting switch QS1 and the second disconnecting switch QS2. These two sets of disconnecting switches QS1 and QS2 ensure that maintenance personnel avoid contact with the external transformer when maintaining the grid-connected circuit 10, thus protecting their personal safety. After maintenance, when the energy storage system needs to be put into operation, the first disconnecting switch QS1 and the second disconnecting switch QS2 should be closed first, followed by the closure of either the first circuit breaker 1QF or the second circuit breaker 2QF as needed.

[0046] In some implementations, the grid-connected branch also includes a first current transformer module and a circuit monitoring module. The first current transformer module is connected in series between the disconnecting switch module and the circuit breaker module, and the circuit monitoring module is configured to monitor the circuit parameters of the first current transformer module.

[0047] Furthermore, the first current transformer module includes a current transformer, and the circuit monitoring module includes a data acquisition and metering submodule and a power quality monitoring submodule.

[0048] The data acquisition and metering submodule is connected to the first current transformer. The data acquisition and metering submodule includes a locally powered data acquisition unit and a metering electricity meter. The data acquisition and metering submodule is configured to acquire the current at the first current transformer and the active and reactive power corresponding to the current over a period of time.

[0049] The power quality monitoring submodule is connected to the second current transformer and is configured to acquire power quality information corresponding to the current introduced by the grid-connected branch.

[0050] Furthermore, the grid-connected branch also includes an anti-islanding protection module, which is connected to the third current transformer. The anti-islanding protection module is configured to control the circuit breaker module to disconnect when the voltage or frequency at the third current transformer fluctuates and the amplitude of the fluctuation exceeds a preset value.

[0051] For details, please refer to further information. Figure 2 For the first grid-connected branch 111, the first current transformer module includes current transformer 1#CT11, current transformer 2#CT12, and current transformer 3#CT13. The circuit monitoring module 1111 includes a data acquisition and metering submodule 11111 and a power quality monitoring submodule 11112, wherein the data acquisition and metering submodule 11111 is connected to current transformer 1#CT11, and the power quality monitoring submodule 11112 is connected to current transformer 2#CT12. In addition, the first grid-connected branch 111 also includes an anti-islanding protection module 1112, which is connected to current transformer 3#CT13.

[0052] Symmetrically, for the second grid-connected branch 112, the first current transformer module includes current transformers 4# CT21, 5# CT22, and 6# CT23. The circuit monitoring module 1121 includes a data acquisition and metering submodule 11211 and a power quality monitoring submodule 11212, wherein the data acquisition and metering submodule 11211 is connected to current transformer 4# CT21, and the power quality monitoring submodule 11212 is connected to current transformer 5# CT22. Furthermore, the second grid-connected branch 112 also includes an anti-islanding protection module 1122, which is connected to current transformer 6# CT23.

[0053] It should be added that, Figure 2 The current transformers 1#CT11, 2#CT12, 3#CT13, 4#CT21, 5#CT22, and 6#CT23 can represent a single current transformer or a group of multiple current transformers. The choice between using a single current transformer or a group of current transformers can be made based on the actual situation, and this application does not impose any specific limitations.

[0054] For example, in the first grid-connected branch 111, the data acquisition and metering submodule 11111 includes a data acquisition unit and a metering electricity meter with local power supply. The local power supply for the data acquisition unit and the metering electricity meter is generally provided by the first auxiliary power supply module 12. The power quality monitoring module 11112 generally includes a power quality monitoring device.

[0055] Correspondingly, in the second grid-connected branch 112, the data acquisition and metering submodule 11211 also includes a data acquisition unit and a metering energy meter with local power supply. The local power supply for the aforementioned data acquisition unit and metering energy meter is generally provided by the first auxiliary power supply module 12. The power quality monitoring module 11212 generally includes a power quality monitoring device.

[0056] The aforementioned data acquisition and metering submodule is used to measure various circuit parameters at the connected current transformer. The specific parameters measured can be adjusted by changing the type of the electricity meter; this application does not impose specific limitations. For example, the circuit parameters include at least current, active power, and reactive power. The power quality monitoring device is used to measure power quality information at the connected current transformer. When selecting an external transformer, the aforementioned energy management unit (EMS) can, in addition to considering the transformer load, also evaluate based on the monitoring data from the aforementioned data acquisition and metering submodule and power quality monitoring module, indirectly selecting the external transformer that needs to be connected.

[0057] Furthermore, in the first grid-connected branch 111, the anti-islanding protection module 1112 is connected to current transformer 3#CT13. Conversely, in the second grid-connected branch 112, the anti-islanding protection module 1122 is connected to current transformer 6#CT23. Generally, the aforementioned anti-islanding protection modules are connected between the secondary winding output of the corresponding current transformer and the circuit breaker of the corresponding grid-connected branch. For example, taking the first grid-connected branch 111 as an example, the anti-islanding protection module 1112 is connected between current transformer 3#CT13 and the first circuit breaker 1QF. The purpose of setting up the anti-islanding protection module is to trigger the anti-islanding protection module when a voltage or current frequency exceeding the preset fluctuation limit occurs in the corresponding grid-connected branch (i.e., an islanding phenomenon occurs). The anti-islanding protection module then controls the circuit breaker in the corresponding branch to open, thereby protecting the components on the branch and other equipment in the energy storage system. For example, taking the first grid-connected branch 111 as an example, when the first grid-connected branch 111 experiences an islanding phenomenon, the anti-islanding protection module 1112 is triggered, controlling the first circuit breaker 1QF to disconnect, thereby opening the circuit of the first grid-connected branch 111, thus ensuring the safety of all components in the first grid-connected branch 111 and the energy storage system.

[0058] In addition, Figure 2 In addition to the cases shown, in some examples, the first current transformer module may also include only one current transformer. The aforementioned data acquisition and metering submodule 11211, power quality monitoring submodule 11212 and anti-islanding protection module 1112 are all connected to the same current transformer to achieve their respective technical objectives in the above embodiments.

[0059] In some embodiments, the first auxiliary power supply circuit 12 includes a socket, a surge protection device SPD1, and multiple miniature circuit breakers;

[0060] The miniature circuit breaker is connected between the socket and the grid-connected branch, or between the surge protection device SPD1 and the grid-connected branch;

[0061] The socket is connected to the external power grid, and the surge protection device SPD1 is grounded.

[0062] For details, please continue reading Figure 2 , Figure 2An exemplary first auxiliary power supply circuit 12 equipped with three sets of miniature circuit breakers is shown. Miniature circuit breakers 1#MCCB1 and 2#MCCB2 are connected to an external circuit via a socket. When miniature circuit breakers 1#MCCB1 and 2#MCCB2 are turned on, the grid-connected circuit 10 can draw power from the external power grid through the socket to provide auxiliary power to other components in the grid-connected circuit 10. Miniature circuit breaker 3#MCCB3 is connected to surge protection device SPD1 and grounded. When the grid-connected circuit 10 experiences a surge current or voltage due to lightning strikes or other conditions, the surge protection device SPD1 can be used to protect the grid-connected circuit 10 by turning on miniature circuit breaker 3#MCCB3.

[0063] Thus, the grid-connected circuit provided in this application can be connected to the grid under multiple transformers. Based on the electrical properties of the transformers and the overall situation and electrical properties of the energy storage system, charging and discharging control is performed to reduce the transformer load rate. During the process of power consumption change, peak-valley arbitrage is achieved through charging and discharging control. At the same time, an electrical interlocking device is used to ensure that multiple circuit breakers will not close at the same time, thereby eliminating the hidden danger of transformers with different voltages operating in parallel at the same time and improving the safety of the energy storage system.

[0064] The grid-connected bus circuit in this application includes a grid-connected sub-circuit and a bus sub-circuit; the grid-connected sub-circuit includes the aforementioned grid-connected circuit 10; the bus sub-circuit 20 includes multiple control switches and corresponding energy storage cabinets, with each control switch connected to a unique corresponding energy storage cabinet.

[0065] Specifically, please refer to Figure 3 , Figure 3 The diagram illustrates a grid-connected busbar circuit 100 according to an embodiment of this application, which includes the grid-connected circuit 10 described above. The output of the grid-connected circuit 10 is connected to a busbar sub-circuit 20, wherein the busbar sub-circuit 20 has multiple branches connected in parallel, each branch corresponding to a set of energy storage cabinets, and each branch is equipped with a control switch. For example, please refer to... Figure 3 Control switch 1#QF1 is installed on the branch corresponding to energy storage cabinet #1, control switch 2#QF2 is installed on the branch corresponding to energy storage cabinet #2, control switch (n-1)#QFn-1 is installed on the branch corresponding to energy storage cabinet #(n-1), and control switch n#QFn is installed on the branch corresponding to energy storage cabinet #n. The opening and closing of the above control switches are controlled by the energy management system (EMS). The EMS determines the energy storage cabinet that needs to be charged and discharged based on its own energy storage status and parameters, and switches the control switch on the branch corresponding to the determined energy storage cabinet to the closed state. The grid-connected circuit 10 in the above embodiment is used to realize charging and discharging, while keeping the other control switches in the open state.

[0066] Figure 3 The grid-connected bus circuit 100 shown is relatively simple in structure and is suitable for situations where the grid-connected circuit 10 and the bus sub-circuit 20 are combined and set up in the same distribution cabinet.

[0067] In some embodiments, the bus circuit 20 further includes a second current transformer module 21 and a second auxiliary power supply circuit 22. The second current transformer module 21 includes a circuit breaker QF, one or more current transformers connected in series, and a current meter connected to the current transformers. The second auxiliary power supply circuit 22 includes a socket, a surge protection device SPD2, and multiple miniature circuit breakers. The miniature circuit breakers are connected between the socket and the second current transformer module 21. The socket is connected to the external power grid, and the surge protection device SPD2 is grounded.

[0068] Specifically, please refer to Figure 4 In the busbar circuit 20, the second current transformer module 21 includes a busbar circuit breaker QF, a current transformer 7#CT, and a current meter connected to the current transformer 7#CT. It should be noted that the current transformer 7#CT can represent a single current transformer or a group of current transformers. The choice between a single current transformer or a group of current transformers can be made based on actual conditions; this application does not impose specific limitations. The purpose of setting up the aforementioned current meter is to monitor the total current of the busbar circuit 20 so that the user can promptly disconnect the busbar circuit breaker QF when the total current of the busbar circuit 20 exceeds a preset limit, thereby protecting the safety of all components within the busbar circuit 20 and the energy storage cabinets connected to it. For example, the power supply for the aforementioned current meter is a local power supply, generally provided by the second auxiliary power supply circuit 22.

[0069] Furthermore, Figure 4 An exemplary second auxiliary power supply circuit 22 equipped with three sets of miniature circuit breakers is shown. Miniature circuit breakers 4# MCCB4 and 5# MCCB5 are connected to an external circuit via a socket. When miniature circuit breakers 4# MCCB4 and 5# MCCB5 are turned on, the bus circuit 20 can draw power from the external power grid through the socket to provide auxiliary power to other components in the bus circuit 20. Miniature circuit breaker 6# MCCB6 is connected to surge protection device SPD2 and grounded. When the bus circuit 10 experiences a surge current or voltage due to lightning strikes or other events, the surge protection device SPD2 can be used to protect the bus circuit 20 by turning on miniature circuit breaker 6# MCCB6.

[0070] Figure 4The busbar circuit 20 shown has a second current transformer module 21 and a second auxiliary power supply circuit 22 in its circuit structure, which is suitable for situations where the grid-connected circuit 10 and the busbar circuit 20 are respectively set in different distribution cabinets.

[0071] The energy storage grid-connected cabinet in this application includes the aforementioned grid-connected circuit, external transformer, and auxiliary devices including copper busbars, cabinet, and terminal blocks.

[0072] Under these conditions, the grid-connected circuit 10 is set up separately in a cabinet and the circuit connection is completed through auxiliary devices such as copper busbars and terminal blocks.

[0073] The energy storage combiner grid-connected cabinet in this application includes the grid-connected circuit described above, the grid-connected combiner circuit described above, and auxiliary devices including copper busbars, cabinets, and terminal blocks.

[0074] Under these conditions, the grid-connected circuit 10 and the busbar circuit 20 are simultaneously housed in a single cabinet and connected via auxiliary devices such as copper busbars and terminal blocks.

[0075] The above circuit setup can effectively reduce the number of grid-connected cabinets or busbar grid-connected cabinets, saving cabinet materials and cabinet placement space.

[0076] The energy storage system in this application includes the grid-connected circuit 10 described above, and the energy storage system also includes multiple energy storage cabinets and an energy management system.

[0077] The energy storage system in this application includes the grid-connected busbar circuit 100 described above, and also includes multiple energy storage cabinets and an energy management system.

[0078] In the description of this specification, the references to terms such as "some embodiments," "in one example," "exemplarily," etc., indicate that a specific feature, structure, material, or characteristic described in connection with an embodiment or example is included in at least one embodiment or example of this application. In this specification, the illustrative expressions of the above terms do not necessarily refer to the same embodiment or example. Furthermore, the specific features, structures, materials, or characteristics described may be combined in any suitable manner in one or more embodiments or examples. Moreover, without contradiction, those skilled in the art can combine and integrate the different embodiments or examples described in this specification, as well as the features of different embodiments or examples.

[0079] Any process or method described in the flowchart or otherwise herein can be understood as representing a module, segment, or portion of code comprising one or more executable instructions for implementing a particular logical function or process, and the scope of the preferred embodiments of this application includes additional implementations in which functions may be performed not in the order shown or discussed, including substantially simultaneously or in reverse order depending on the function involved, as will be understood by those skilled in the art to which embodiments of this application pertain.

[0080] Although embodiments of this application have been shown and described above, it is understood that the above embodiments are exemplary and should not be construed as limiting this application. Those skilled in the art can make changes, modifications, substitutions and variations to the above embodiments within the scope of this application.

Claims

1. A grid-connected circuit, characterized in that, The grid-connected circuit includes a first auxiliary power supply circuit and multiple sets of grid-connected branches. The first auxiliary power supply circuit is electrically connected to the multiple sets of grid-connected branches. The first auxiliary power supply circuit is configured to provide auxiliary power supply and overvoltage protection to the grid-connected branches. The multiple sets of grid-connected branches are connected in parallel and are connected to the matching bus circuit. The multiple sets of grid-connected branches are configured to be electrically connected to the corresponding external transformer circuit respectively. Electrical interlocks are provided between the multiple sets of grid-connected branches to ensure that only one set of grid-connected branches is in operation at any given time, or that none of the multiple sets of grid-connected branches are in operation at any given time.

2. The grid-connected circuit according to claim 1, characterized in that, The grid-connected branch includes a disconnect switch module and a circuit breaker module. The disconnect switch module is configured to protect the safety of maintenance personnel in the event of maintenance of the grid-connected circuit. The electrical interlock is provided in the circuit breaker module, which is configured to control the on / off state of the grid-connected branch.

3. The grid-connected circuit according to claim 2, characterized in that, The grid-connected branch also includes a first current transformer module and a circuit monitoring module. The first current transformer module is connected in series between the disconnecting switch module and the circuit breaker module. The circuit monitoring module is configured to monitor the circuit parameters of the first current transformer module.

4. The grid-connected circuit according to claim 3, characterized in that, The first current transformer module includes a current transformer, and the circuit monitoring module includes a data acquisition and metering submodule and a power quality monitoring submodule. The acquisition and metering submodule is connected to the first current transformer. The acquisition and metering submodule includes a locally powered acquisition unit and a metering electricity meter. The acquisition and metering submodule is configured to acquire the current at the first current transformer and the active and reactive power corresponding to the current over a period of time. The power quality monitoring submodule is connected to the second current transformer, and the power quality monitoring submodule is configured to acquire power quality information corresponding to the current introduced by the grid-connected branch.

5. The grid-connected circuit according to claim 4, characterized in that, The grid-connected branch also includes an anti-islanding protection module, which is connected to a third current transformer. The anti-islanding protection module is configured to control the circuit breaker module to disconnect when the voltage or frequency at the third current transformer fluctuates and the amplitude of the fluctuation is greater than a preset value.

6. The grid-connected circuit according to claim 1, characterized in that, The first auxiliary power supply circuit includes a socket, a surge protection device, and multiple miniature circuit breakers; The miniature circuit breaker is connected between the socket and the grid-connected branch, or between the surge protection device and the grid-connected branch; The socket is connected to the external power grid, and the surge protection device is grounded.

7. A grid-connected bus circuit, characterized in that, The grid-connected bus circuit includes a grid-connected sub-circuit and a bus sub-circuit; The grid-connected sub-circuit includes the grid-connected circuit as described in any one of claims 1-6; The busbar circuit includes multiple control switches and corresponding energy storage cabinets, with each control switch connected to a unique corresponding energy storage cabinet.

8. The grid-connected bus circuit according to claim 7, characterized in that, The busbar circuit also includes a second current transformer module and a second auxiliary power supply circuit. The second current transformer module includes a circuit breaker, one or more current transformers connected in series, and a current meter connected to the current transformers. The second auxiliary power supply circuit includes a socket, a surge protection device, and multiple miniature circuit breakers. The miniature circuit breakers are connected between the socket and the second current transformer module. The socket is connected to an external power grid, and the surge protection device is grounded.

9. An energy storage grid-connected cabinet, characterized in that, The energy storage grid-connected cabinet includes the grid-connected circuit as described in any one of claims 1-6 and auxiliary devices including copper busbars, cabinet body, and terminal blocks.

10. An energy storage combiner grid-connected cabinet, characterized in that, The energy storage and grid-connected cabinet includes the grid-connected circuit as described in any one of claims 1-6, the grid-connected bus circuit as described in any one of claims 7-8, and auxiliary devices including copper busbars, cabinets, and terminal blocks.

11. An energy storage system, characterized in that, The energy storage system includes the grid-connected circuit as described in any one of claims 1-6, and the energy storage system further includes multiple energy storage cabinets and an energy management system.

12. An energy storage system, characterized in that, The energy storage system includes the grid-connected busbar circuit as described in claim 7 or 8, and the energy storage system also includes multiple energy storage cabinets and an energy management system.

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