Grid-connected and off-grid switching device and power system

Abstract

The invention discloses a grid-connected and off-grid switching device and a power system, and belongs to the technical field of power electronics. The grid-connected and off-grid switching device comprises a plurality of modularized cabinet bodies, each modularized cabinet body comprises a bus chamber, a switch chamber and a cable chamber which are sequentially arranged in the vertical direction, a bus unit is arranged in the bus chamber, a switch and control unit is arranged in the switch chamber, a cable is arranged in the cable chamber, and the cable is electrically connected with the bus unit through the switch and control unit; the modularized cabinet bodies are connected in a combined cabinet mode, so that the bus units are connected, the cable in at least one modularized cabinet body is used for being electrically connected with a power grid, the cable in at least one modularized cabinet body is used for being electrically connected with an inverter, and the cable in at least one modularized cabinet body is used for being electrically connected with a load. Through the modular design of the cabinet body structure, the installation scene adaptability is higher, and the electrical scheme modular design can also enhance the expansibility and the adaptability.

Description

Technical Field

[0001] This application belongs to the field of power electronics technology, and in particular relates to a grid-connected switching device and a power system. Background Technology

[0002] Off-grid backup power cabinets (also known as integrated photovoltaic-storage on-grid and off-grid cabinets) are comprehensive energy devices that integrate energy storage, photovoltaic power generation, grid interaction, and microgrid management. They support seamless switching between on-grid and off-grid modes and are widely used in industrial, commercial, and residential scenarios. Traditional on-grid and off-grid backup power cabinets suffer from problems such as low development efficiency, insufficient market adaptability, limited scalability due to single solutions, and the spread of single faults with high expansion costs. Summary of the Invention

[0003] This invention aims to solve at least one of the technical problems existing in the prior art. To this end, this invention proposes a grid-connected / off-grid switching device and power system, which has stronger adaptability to installation scenarios and higher scalability and adaptability.

[0004] In a first aspect, this application provides a grid-connected / off-grid switching device, including multiple modular cabinets. Each modular cabinet includes a busbar compartment, a switch compartment, and a cable compartment arranged sequentially in a vertical direction. The busbar compartment is equipped with a busbar unit, the switch compartment is equipped with a switch and a control unit, and the cable compartment is equipped with a cable. The cable is electrically connected to the busbar unit through the switch and the control unit. The modular cabinets are connected in parallel to connect the busbar units. At least one modular cabinet has a cable for electrical connection to the power grid, at least one modular cabinet has a cable for electrical connection to the inverter, and at least one modular cabinet has a cable for electrical connection to the load. The modular cabinet connected to the power grid includes a grid-connected and off-grid switching switch and a grid-connected and off-grid control unit. The grid-connected and off-grid switching switch is electrically connected between the bus unit and the cable. The grid-connected and off-grid control unit is configured to control the grid-connected and off-grid switching switch to be turned on or off.

[0005] According to one embodiment of this application, the modular cabinet has a first through hole in the busbar compartment, and one busbar unit of the two modular cabinets is connected to the other busbar unit through the first through hole via a plug-in terminal.

[0006] According to one embodiment of this application, at least one modular cabinet has a secondary terminal in its switch chamber, which is electrically connected to the busbar unit and / or the switch and control unit.

[0007] According to one embodiment of this application, the modular cabinet has a second through hole in the switch compartment, and the secondary terminals are modular terminals with male and female connectors. One end of the male and female connectors is electrically connected to the busbar unit and / or the switch and control unit, and the other end is electrically connected to a component in another modular cabinet connected to the same cabinet through the second through hole.

[0008] According to one embodiment of this application, the modular cabinet has an air inlet at the bottom, an air outlet at the top, and a fan inside the modular cabinet. The air inlet, air outlet, and fan define a unidirectional air duct within the modular cabinet.

[0009] According to one embodiment of this application, the air inlet is located on the side panel of the modular cabinet and is arranged close to the bottom plate, the air outlet is located on the top plate of the modular cabinet, the air inlet is provided with a straight ventilation louver, and the fan is an axial flow fan.

[0010] According to one embodiment of this application, cables within a plurality of modular cabinets are used for electrical connection to an inverter, and the plurality of modular cabinets electrically connected to the inverter have a plurality of power ratings. The power rating of the off-grid switching device is in the megawatt range.

[0011] According to one embodiment of this application, at least one cable within a modular cabinet is used for electrical connection to a generator; and / or, The cables inside the multiple modular cabinets are used for electrical connection to the inverter.

[0012] According to one embodiment of this application, the modular cabinet electrically connected to the power grid and the modular cabinet electrically connected to the load are the same cabinet.

[0013] Secondly, this application provides a power system including the aforementioned grid-connected / off-grid switching device.

[0014] According to the grid-connected and off-grid switching device and power system of this application, by modular design of the cabinet structure, front operation and front maintenance, it can be installed against the wall and at a corner, or installed in parallel cabinets, making it more adaptable to different installation scenarios. Furthermore, the modular design of the electrical scheme can enhance scalability and adaptability.

[0015] Additional aspects and advantages 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 this application. Attached Figure Description

[0016] The above and / or additional aspects and advantages of the present invention will become apparent and readily understood from the description of the embodiments taken in conjunction with the following drawings, in which: Figure 1 This is one of the schematic diagrams of modular cabinets provided in the embodiments of this application; Figure 2 This is a schematic diagram of the external shape of the modular cabinet provided in the embodiment of this application; Figure 3 This is a schematic diagram of the internal structure of the modular cabinet provided in the embodiments of this application; Figure 4 This is the second schematic diagram of the modular cabinet provided in the embodiments of this application; Figure 5 This is a schematic diagram of the busbar connection structure provided in the embodiments of this application; Figure 6 These are three structural views of the secondary terminal provided in the embodiments of this application; Figure 7 This is a front thermal convection diagram of the grid-connected / off-grid switching device provided in the embodiments of this application; Figure 8 This is a rear thermal convection diagram of the grid-connected / off-grid switching device provided in the embodiments of this application; Figure 9 This is a thermal convection diagram of the back side of the grid-connected / off-grid switching device provided in the embodiments of this application.

[0017] Figure label: Modular cabinet 10, busbar compartment 11, switch compartment 12, cable compartment 13, plug-in terminal 14, air inlet 15, air outlet 16. Detailed Implementation

[0018] The embodiments of this application are described in detail below. Examples of these 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 this application, and should not be construed as limiting this application.

[0019] In the following description, a "circuit" refers to a conductive loop consisting of at least one element or sub-circuit connected by an electrical or electromagnetic link. When an element or circuit is said to be "coupled to" or "connected to" another element, or when an element / circuit is said to be "coupled at" or "connected at" two nodes, it can be directly coupled to or connected to the other element, or there may be intermediate elements. The connection between elements can be physical, logical, or a combination thereof. Conversely, when an element is said to be "directly coupled to" or "directly connected to" another element, it means that there are no intermediate elements between them.

[0020] In the description, the terms "first," "second," etc., are used to distinguish similar objects, not to describe a specific order or sequence. It should be understood that such numerical descriptors can be interchanged where appropriate so that embodiments of this application can be implemented in orders other than those illustrated or described herein, and the objects distinguished by "first," "second," etc., are generally of the same class, not limited in number; for example, a first object can be one or more. Furthermore, in the specification and claims, "and / or" indicates at least one of the connected objects, and the character " / " generally indicates that the preceding and following objects are in an "or" relationship.

[0021] Furthermore, the use of terms such as "one embodiment," "some embodiments," "illustrative embodiment," "example," "specific example," or "some examples" indicates that a specific feature, structure, material, or characteristic described in connection with that 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. Moreover, the specific features, structures, materials, or characteristics described may be combined in any suitable manner in one or more embodiments or examples.

[0022] Reference Figure 1 , Figure 2 and Figure 3 , Figure 1 This is a schematic diagram of the modular cabinet provided in the embodiments of this application. Figure 2 This is a schematic diagram of the external shape of the modular cabinet provided in the embodiment of this application. Figure 3 This is a schematic diagram of the internal structure of the modular cabinet provided in an embodiment of this application. One embodiment of this application proposes a grid-connected / off-grid switching device.

[0023] In this embodiment, the grid-connected / off-grid switching device includes multiple modular cabinets 10. Each modular cabinet 10 includes a busbar compartment 11, a switch compartment 12, and a cable compartment 13 arranged vertically in sequence. The busbar compartment 11 contains busbar units, the switch compartment 12 contains switches and control units, and the cable compartment 13 contains cables. The cables are electrically connected to the busbar units through the switches and control units. The modular cabinets 10 are connected in parallel to connect the busbar units. At least one modular cabinet 10 contains cables for electrical connection to the power grid, at least one modular cabinet 10 contains cables for electrical connection to the inverter, and at least one modular cabinet 10 contains cables for electrical connection to the load. The switches and control units of the modular cabinets 10 connected to the power grid include grid-connected / off-grid switching switches and grid-connected / off-grid control units. The grid-connected / off-grid switching switches are electrically connected to the busbar units and the cables, and the grid-connected / off-grid control units are configured to control the grid-connected / off-grid switching switches to be turned on or off.

[0024] Modular cabinet 10 refers to a structured cabinet based on the same dimensions, such as the standard dimensions of a low-voltage switchgear. As an example, a single modular cabinet 10 can have a width of 800mm, a depth of 1000mm, and a height of 2200mm. Of course, these values ​​can be set according to requirements. For example, the width can be between 600mm and 1000mm, the depth between 800mm and 1200mm, and the height between 2000mm and 2400mm.

[0025] The main body of the modular cabinet 10 can be composed of a plate or beam structure made of materials such as metal or plastic. The internal space can also be defined by plates or beams to divide the busbar compartment 11, switch compartment 12, and cable compartment 13. The partition plates or beams between the busbar compartment 11, switch compartment 12, and cable compartment 13 can be provided with mounting holes (such as 25mm modular holes) for installing each functional unit.

[0026] Each modular cabinet 10 is used to build relatively independent functional units of the electrical scheme, forming different functions based on the specific configuration of the internal switch compartment 12 and cable compartment 13. For example, the functional types may include mains power function, diesel generator function, load function, and inverter function.

[0027] The modular cabinet 10 for mains power function refers to the modular cabinet 10 used for electrical connection with the power grid; the modular cabinet 10 for diesel generator function refers to the modular cabinet 10 used for electrical connection with a diesel generator (or other types of generator); the modular cabinet 10 for load function refers to the modular cabinet 10 used for electrical connection with a load; and the modular cabinet 10 for inverter function refers to the modular cabinet 10 used for electrical connection with an inverter.

[0028] Modular cabinet 10 combined refers to two or more modular cabinets 10 connected together. The modular cabinets 10 in the combined cabinet can be fixed together by connecting structures on the main body, such as bolts or flanges. The opposite sides of the two modular cabinets 10 in the combined cabinet can directly contact each other, reducing the distance between the modular cabinets 10.

[0029] The busbar unit mainly consists of busbars, which can be cables or copper busbars. When the modular cabinets 10 are connected in parallel, the busbars are connected together to form a series busbar, thus pooling the power systems within each modular cabinet 10. When each modular cabinet 10 is connected to the power grid, load, diesel generator, or inverter, the power grid, load, diesel generator, or inverter are connected to the same series busbar to achieve power distribution.

[0030] The specific configuration of switches, control units, and cables can be set according to the functional type of the modular cabinet 10. Each switch can be a relay or an MCCB (molded case circuit breaker). The cables vary depending on the object to be connected. For example, the cables in the modular cabinet 10 connected to the power grid can be three- or four-wire; the cables in the modular cabinet 10 connected to the load can be two-phase; and the cables in the modular cabinet 10 connected to the inverter can be two-phase or three-phase. Of course, cables with different voltage withstand capacities can also be selected based on the power requirements of the object.

[0031] The control unit may include a controller, which may be implemented using an MCU (Microcontroller Unit) chip; or it may be based on a DSP (Digital Signal Processor) chip, an FPGA (Field Programmable Gate Array) chip, or a custom controller chip.

[0032] Typically, a modular cabinet 10 within the grid-connected / off-grid switching device is electrically connected to the power grid. This modular cabinet 10 primarily manages the power supply between the device and the grid. When the grid-connected / off-grid switching switch within the modular cabinet 10 is closed, the device is in a grid-connected state; when the grid-connected / off-grid switching switch within the modular cabinet 10 is open, the device is in an off-grid state. The grid-connected / off-grid switching switch can be a relay, etc.

[0033] As an example, some modular cabinets 10 can also isolate a secondary compartment 12 within the switch compartment, which can be used to house control units, thus achieving isolation between the switch and the control unit.

[0034] The grid-connected / off-grid control unit can adopt a modular single-board design and be centrally installed in the secondary room near the grid-connected / off-grid switching switch, resulting in short wiring and minimal interference. Furthermore, the controller can employ high-precision sampling circuits and high-performance AI chips, enabling rapid sampling and logic judgment, achieving a grid-connected / off-grid switching time of <20ms.

[0035] The on-grid and off-grid switching device also includes at least one modular cabinet 10 that realizes the load function and at least one inverter function, to build a basic power network and realize the electrical solution of "mains power + load + inverter".

[0036] In some embodiments, the modular cabinet 10 electrically connected to the power grid and the modular cabinet 10 electrically connected to the load are the same cabinet.

[0037] Considering that grid-connected and off-grid switching devices typically need to operate under load, integrating the modular cabinet 10 that implements both load and grid functions into one unit can further improve the compactness of the grid-connected and off-grid switching device. The load function can also be directly paralleled with the downstream distribution cabinet, achieving electrical coupling at proximity and reducing customer wiring costs.

[0038] As an example, the modular cabinet 10 integrating load and power grid functions can be twice the standard size in width. Taking the aforementioned standard size as an example, the modular cabinet 10 can be 1600mm wide, 1000mm deep, and 2200mm high. Of course, the width can also be adjusted according to the volume of the internal functional units, such as 1000mm, 1200mm, or 1400mm.

[0039] According to the on-grid / off-grid switching device of this embodiment, the cabinet structure is modularly designed, allowing for front operation and maintenance. It can be installed against the wall or at a corner, or in a parallel cabinet, making it more adaptable to different installation scenarios. Furthermore, the modular design of the electrical scheme can enhance its expandability and adaptability.

[0040] In some embodiments, cables within multiple modular cabinets 10 are used for electrical connection to an inverter, and the multiple modular cabinets electrically connected to the inverter have multiple power ratings; and the power rating of the off-grid switching device is megawatt level.

[0041] It should be noted that the modular cabinet 10, which is electrically connected to the inverter, can have multiple internal wirings to connect multiple inverters. However, all cables in this type of modular cabinet 10 are of the same specification, ensuring that the connected inverters have the same power rating. This embodiment uses multiple modular cabinets 10 electrically connected to the inverters to connect various inverters with different power ratings, realizing an electrical scheme of "mains power + load + N * inverters". The inverters can have power ratings of 80kW, 100kW, or 125kW, etc.

[0042] As an example, the modular cabinet 10 electrically connected to the inverter includes cabinet A and cabinet B. Cabinet A can support an 80kW inverter, and cabinet B supports 15 inverters ranging from 100 to 125kW. Cabinets A and B can be connected in parallel to meet the mixed connection requirements of inverters with different power ratings. The switches and cables in cabinets A and B can use devices and wires of corresponding power ratings.

[0043] In this embodiment, by connecting a large number of inverters, the power level of the grid-connected / off-grid switching device is increased to the megawatt level. The grid-connected / off-grid switching device can cover three types of high-power grid-connected / off-grid cabinets: 1.6MW, 2.0MW, and 2.4MW, realizing a seamless grid-connected / off-grid switching system with an ultra-high power of 2.4MW.

[0044] In some embodiments, cables within at least one modular cabinet 10 are used for electrical connection to a generator; and / or cables within multiple modular cabinets are used for electrical connection to an inverter.

[0045] The generator can be a diesel generator, with at least one modular cabinet 10 realizing the diesel generator function, achieving an electrical solution of "mains power + load + inverter + diesel generator". Of course, the generator can also be other types of generators.

[0046] In this embodiment, multiple modular cabinets 10 can also be electrically connected to the inverter to achieve an electrical solution of "mains power + load + N*inverter + diesel generator". This allows for the upgrading, expansion, and flexible combination of various electrical solutions. The configuration scheme of the modular cabinet 10 with multiple inverter functions can be referred to the above.

[0047] Reference Figure 4 , Figure 4 This is a schematic diagram of the modular cabinets provided in this application embodiment. As an example, the grid-connected / off-grid switching device includes four modular cabinets 10, of which the left one is a modular cabinet 10 integrating load function and mains power function, and the others are a modular cabinet 10 with diesel generator function and two modular cabinets 10 with inverter function. The volume of the modular cabinet 10 integrating load function and mains power function is twice that of the other modular cabinets 10.

[0048] Compared to conventional backup power cabinets that integrate mains power, diesel generator, load, and inverter, which lack sufficient functionality to support client-side loads or other inverter expansions due to their high integration level, conventional backup power cabinets also come standard with a diesel generator interface, leaving this interface resource idle when the user does not configure a diesel generator. The electrical solution provided in this implementation method features a modular design, enhanced scalability and adaptability, and richer interface functionality.

[0049] Reference Figure 5 , Figure 5 This is a schematic diagram of the busbar connection structure provided in an embodiment of this application. In some embodiments, the modular cabinet 10 has a first through hole in the busbar compartment 11, and one busbar unit of the two modular cabinets 10 is connected to the other busbar unit through the first through hole via a plug-in terminal 14.

[0050] In this embodiment, the busbar may have plug-in structures at both ends, one end for connecting to the plug-in terminal 14, and the other end for plugging into the plug-in terminal 14. The busbar may be made of copper busbar, which facilitates connection to the plug-in terminal 14 and plugging. The first through hole provides a reserved plugging position for the busbar chamber 11.

[0051] When two modular cabinets 10 are connected together, a section of the busbar in the busbar compartment 11 of one modular cabinet 10 is connected to a plug-in terminal 14. This plug-in terminal 14 is inserted into the busbar compartment 11 of the other modular cabinet 10 through the first through holes of the two modular cabinets 10, and the plug-in terminal 14 is connected to the other busbar.

[0052] In some embodiments, at least one modular cabinet 10 has a secondary terminal in its switch chamber, which is electrically connected to the busbar unit and / or the switch and control unit.

[0053] Secondary terminals can be used to expand the connection methods within the modular cabinet 10, and can be arranged in the aforementioned secondary compartment. For example, secondary terminals and busbar units can extend power branches from the busbar, which can be used for power supply, etc. Alternatively, secondary terminals can be connected to switches and control units to extend signal loops, which can be used for signal input or output, thereby providing more control methods and realizing flexible strategy configuration.

[0054] In some embodiments, the modular cabinet 10 has a second through hole in the switch chamber 12, and the secondary terminal is a modular terminal with a male and a female connector. One end of the male and female connectors is electrically connected to the busbar unit and / or the switch and control unit, and the other end is electrically connected to a component in another modular cabinet 10 connected to the same cabinet through the second through hole.

[0055] Reference Figure 6 , Figure 6 These are three views of the secondary terminals provided in this embodiment. The secondary terminals can be directly plugged in using male and female terminals, facilitating online parallel expansion and improving the safety and convenience of secondary wiring. The second through hole provides a reserved plugging position for the switch compartment 12.

[0056] As an example, a modular cabinet 10 that implements the mains power function and a modular cabinet 10 that implements the inverter function are installed side-by-side, and both modular cabinets 10 are equipped with secondary terminals. These two secondary terminals are directly connected via a second through-hole. Thus, the grid-connected control unit can communicate with the inverter control unit through the two secondary terminals, thereby achieving interactive control and improving the flexibility and reliability of mains power control and inverter control. This communication can be used to mutually generate sampling information such as voltage or current from their respective modular cabinets 10.

[0057] Compared to conventional backup power cabinets, where the core units, such as the centrally located busbar and relatively complex primary and secondary wiring, feature a modular design for the core units, with a top-mounted front busbar that allows for busbar paralleling and online capacity expansion. Modular paralleling terminal blocks optimize internal circuit layout and wiring, enhancing both safety and convenience.

[0058] In some embodiments, the modular cabinet 10 has an air inlet 15 at the bottom, an air outlet 16 at the top, and a fan inside the modular cabinet. The air inlet 15, the air outlet 16, and the fan define a unidirectional air duct within the modular cabinet 10.

[0059] This implementation method utilizes the thermal pressure difference (chimney effect) generated by the temperature difference between the inside and outside of the cabinet as the basic heat dissipation method. By constructing a unidirectional hot air flow channel that flows from bottom to top in a uniform direction and is highly efficient and forced, the method can achieve directional and efficient removal of a large amount of waste heat generated by high-power devices (such as frame circuit breakers and copper busbars) inside the cabinet.

[0060] Understandably, the modular cabinet 10 may also include sensor devices such as temperature sensors, and the temperature sensors and fans can be connected to the control unit inside the cabinet. The control unit receives feedback signals from the temperature sensors and other sensor devices, monitors the temperature inside the cabinet, and adjusts the fan speed accordingly to achieve intelligent adjustment of heat dissipation capacity.

[0061] As an example, the air inlet 15 is located on the side panel of the modular cabinet and is arranged close to the bottom plate, the air outlet 16 is located on the top plate of the modular cabinet, the air inlet 15 is equipped with a straight ventilation louver, and the fan is an axial flow fan.

[0062] The number of axial flow fans can be one or more, and they can be arranged close to the air outlet 16. The direct ventilation louvers of the air inlet 15 can be used to passively induce low-temperature air into the cabinet, while the axial flow fans are used to actively exhaust high-temperature air. Through the coordinated design of passive air intake and active air exhaust, a highly efficient and directional hot air channel is constructed, which greatly improves the heat dissipation efficiency and meets the heat dissipation requirements of high-power-density cabinets.

[0063] Reference Figure 7 , Figure 8 and Figure 9 , Figure 7 This is a front thermal convection diagram of the grid-connected / off-grid switching device provided in the embodiments of this application. Figure 8 This is a rear thermal convection diagram of the grid-connected / off-grid switching device provided in the embodiments of this application. Figure 9 This is a thermal convection diagram of the back side of the grid-connected / off-grid switching device provided in the embodiments of this application.

[0064] In this example, the bottom-in, top-out air duct layout conforms to the laws of hot air flow, has a simple structure, requires no complex internal air ducts, and is low in cost and easy to maintain. The fault redundancy provided by natural convection improves the reliability of the system in abnormal situations such as fan failure.

[0065] The control unit can also determine, based on sensor signals, that when the off-grid equipment is at low temperature or light load, it can rely on natural convection or low-speed fan operation, thereby reducing energy consumption and operating noise.

[0066] One embodiment of this application also provides a power system including the aforementioned grid-connected / off-grid switching device. The specific structure and principle of the grid-connected / off-grid switching device can be referred to the foregoing embodiments.

[0067] The power system may include at least one of the following: a grid system connected to an on-grid switching device, at least one inverter, at least one load, and at least one diesel generator.

[0068] According to the power system of this application, by adopting a modular cabinet structure, front operation and front maintenance can be achieved, wall-mounted installation and corner installation, as well as parallel cabinet installation, making the installation scenario more adaptable. Furthermore, the modular design of the electrical solution can also enhance scalability and adaptability.

[0069] In this document, the terms "comprising," "including," or any other variations thereof are intended to cover non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements includes not only those elements but also other elements not expressly listed, or elements inherent to such a process, method, article, or apparatus. Without further limitation, an element defined by the phrase "comprising one..." does not exclude the presence of other identical elements in the process, method, article, or apparatus that includes that element. Furthermore, it should be noted that the scope of the methods and apparatuses in the embodiments of this application is not limited to performing functions in the order shown or discussed, but may also include performing functions substantially simultaneously or in the reverse order, depending on the functions involved. For example, the described methods may be performed in a different order than described, and various steps may be added, omitted, or combined. Additionally, features described with reference to certain examples may be combined in other examples.

[0070] Although embodiments of this application have been shown and described, those skilled in the art will understand that various changes, modifications, substitutions and alterations can be made to these embodiments without departing from the principles and spirit of this application, the scope of which is defined by the claims and their equivalents.

Claims

1. A grid-connected / off-grid switching device, characterized in that, It includes multiple modular cabinets, each of which includes a busbar compartment, a switch compartment, and a cable compartment arranged sequentially in a vertical direction. The busbar compartment contains a busbar unit, the switch compartment contains a switch and control unit, and the cable compartment contains a cable. The cable is electrically connected to the busbar unit through the switch and control unit. The modular cabinets are connected in parallel to connect the busbar units. At least one of the cables in the modular cabinet is used for electrical connection to the power grid, at least one of the cables in the modular cabinet is used for electrical connection to the inverter, and at least one of the cables in the modular cabinet is used for electrical connection to the load. The modular cabinet electrically connected to the power grid includes a grid-connected / off-grid switching switch and a grid-connected / off-grid control unit. The grid-connected / off-grid switching switch is electrically connected between the bus unit and the cable. The grid-connected / off-grid control unit is configured to control the grid-connected / off-grid switching switch to be turned on or off.

2. The grid-connected / off-grid switching device according to claim 1, characterized in that, The modular cabinet has a first through hole in the busbar compartment, and one of the busbar units in the two modular cabinets is connected to the other busbar unit through the first through hole via a plug-in terminal.

3. The grid-connected / off-grid switching device according to claim 2, characterized in that, At least one of the modular cabinets has a secondary terminal in the switch chamber, which is electrically connected to the busbar unit and / or the switch and control unit.

4. The grid-connected / off-grid switching device according to claim 3, characterized in that, The modular cabinet has a second through hole in the switch compartment. The secondary terminal is a modular terminal with a male and a female connector. One end of the male connector and the female connector is electrically connected to the busbar unit and / or the switch and control unit, and the other end is connected to the component electrical terminal in another modular cabinet connected to the same cabinet through the second through hole.

5. The grid-connected / off-grid switching device according to any one of claims 1-4, characterized in that, The modular cabinet has an air inlet at the bottom and an air outlet at the top. A fan is installed inside the modular cabinet, and the air inlet, the air outlet, and the fan define a unidirectional air duct within the modular cabinet.

6. The grid-connected / off-grid switching device according to claim 5, characterized in that, The air inlet is located on the side panel of the modular cabinet and is arranged close to the bottom plate. The air outlet is located on the top plate of the modular cabinet. The air inlet is equipped with a straight ventilation louver. The fan is an axial flow fan.

7. The grid-connected / off-grid switching device according to any one of claims 1-4, characterized in that, The cables within the multiple modular cabinets are used for electrical connection to the inverter, and the multiple modular cabinets electrically connected to the inverter have multiple power ratings; The power rating of the on-grid / off-grid switching device is in the megawatt range.

8. The grid-connected / off-grid switching device according to any one of claims 1-4, characterized in that, At least one of the cables within the modular cabinet is used for electrical connection to a generator; and / or, The cables within the multiple modular cabinets are used for electrical connection to the inverter.

9. The grid-connected / off-grid switching device according to any one of claims 1-4, characterized in that, The modular cabinet electrically connected to the power grid and the modular cabinet electrically connected to the load are the same cabinet.

10. An electric power system, characterized in that, The power system includes a grid-connected / off-grid switching device according to any one of claims 1-9.

Images