Photovoltaic grid-connected cabinet

Abstract

The application belongs to the technical field of photovoltaic, and specifically discloses a photovoltaic grid-connected cabinet. The photovoltaic grid-connected cabinet is characterized in that the first circuit breaker is arranged below the mutual inductor unit, the second circuit breaker is arranged side by side with the first circuit breaker and below the mutual inductor unit, the disconnector is arranged below the first circuit breaker, the power generation cable is connected with the photovoltaic power generation side and the second circuit breaker, and the outgoing cable is connected with the disconnector and the power consumption side, so that the external cable connected with the photovoltaic grid-connected cabinet can enter and exit from the lower part of the cabinet body, the length of the outgoing cable in the cabinet body is shortened, the outgoing cable does not need to be bent, the size of the photovoltaic grid-connected cabinet can be reduced, and the occupied space of the photovoltaic grid-connected cabinet is reduced.

Description

A photovoltaic grid-connected cabinet Technical Field

[0001] This invention relates to the field of photovoltaic technology, and in particular to a photovoltaic grid-connected cabinet. Background Technology

[0002] With the modernization of agriculture, electricity consumption in livestock farming has been steadily increasing in recent years. The demand for photovoltaic (PV) power generation in livestock farms is becoming increasingly prominent. Currently, the "self-consumption with surplus power fed into the grid" model dominates PV grid-connected solutions.

[0003] In a photovoltaic (PV) power generation system, current flows from the generation side to the consumption side. In grid-connected system design, the PV grid-connected cabinet connects multiple inverters in parallel, aggregating the power supply and transmitting it to the consumption side. Therefore, the PV grid-connected cabinet is a crucial link in the power transmission from the generation side to the consumption side. In existing technology, external cables connecting to the generation side enter the PV grid-connected cabinet from the bottom. The current flow inside the cabinet is from bottom to top, and then the cables are led out from the bottom of the cabinet to the consumption side. The cables leading the current to the consumption side typically run from the top to the bottom of the cabinet, occupying space and requiring sufficient construction space within the cabinet due to the cables' thickness and rigidity, resulting in a large bending radius. Summary of the Invention

[0004] The purpose of this invention is to provide a photovoltaic grid-connected cabinet that solves the problem that the cables leading the current to the power consumption side in the photovoltaic grid-connected cabinet usually run from the top to the bottom of the cabinet, which not only occupies space inside the cabinet, but also requires sufficient construction space inside the cabinet because the cables are relatively thick and stiff and have a large bending radius inside the cabinet.

[0005] To achieve this objective, the present invention adopts the following technical solution:

[0006] A photovoltaic grid-connected cabinet includes:

[0007] Cabinet;

[0008] The current transformer unit is disposed at the top of the cabinet along the first direction;

[0009] The first circuit breaker is disposed below the current transformer unit along a first direction, which is the vertical direction of the cabinet;

[0010] A disconnecting switch is disposed below the first circuit breaker along the first direction;

[0011] At least one second circuit breaker is disposed below the current transformer unit along a first direction and is disposed side by side with the first circuit breaker and the disconnecting switch along a second direction, the second direction being perpendicular to the first direction;

[0012] The second circuit breaker's input terminal is used to connect to the power generation cable on the photovoltaic power generation side. The output terminal of the second circuit breaker is connected to the input terminal of the first circuit breaker via a busbar and the current transformer unit. The output terminal of the first circuit breaker is connected to the input terminal of the disconnecting switch. The output terminal of the disconnecting switch is used to connect to the outgoing cable on the power consumption side.

[0013] As an optional technical solution for the aforementioned photovoltaic grid-connected cabinet, the current transformer unit includes three metering current transformers, which correspond one-to-one with the three-phase outgoing terminals of the second circuit breaker. Each phase outgoing terminal of the second circuit breaker is connected to a set of busbars, which pass through the corresponding metering current transformers. The incoming and outgoing terminals of the second circuit breaker are arranged along a third direction, which is perpendicular to the first and second directions.

[0014] The incoming terminal of the first circuit breaker is positioned above the outgoing terminal along a first direction, and the three-phase incoming terminals of the first circuit breaker are connected to the corresponding busbars.

[0015] The incoming terminal of the disconnecting switch is positioned above the outgoing terminal along a first direction. The incoming terminal of the disconnecting switch is connected to the outgoing terminal of the first circuit breaker, and the outgoing terminal of the disconnecting switch is used to connect to the outgoing cable.

[0016] As an optional technical solution for the aforementioned photovoltaic grid-connected cabinet, multiple second circuit breakers are provided, and the multiple second circuit breakers are spaced apart along the first direction. The three-phase input terminals of each second circuit breaker are respectively connected to a first busbar, which is used to connect to the power generation cable.

[0017] The busbar includes a second busbar and a busbar. The three-phase outgoing terminals of each second circuit breaker are respectively connected to the second busbar. The second busbars of the same phase of multiple second circuit breakers are connected in series through the busbar. The busbar passes through the metering transformer and is connected to the incoming terminal of the first circuit breaker.

[0018] As an optional technical solution for the aforementioned photovoltaic grid-connected cabinet, the first busbar and the second busbar extend along the second direction respectively. The busbar includes a first section, a second section and a third section connected in sequence. The first section extends along the first direction and is connected in series with the second busbar. The second section extends along the second direction and passes through the metering transformer. The third section is connected to the incoming terminal of the first circuit breaker.

[0019] As an optional technical solution for the aforementioned photovoltaic grid-connected cabinet, at least one air inlet filter device is provided on the outside of the cabinet. The air inlet filter device includes a filter box, a control component, a drive component, and a protective cover. The filter box is disposed on the cabinet, and the protective cover is disposed on the outside of the filter box. The protective cover is provided with an air inlet hole. The drive component is connected to the protective cover, and the control component is used to control the drive component to drive the protective cover to open or to cover the outside of the filter box.

[0020] As an optional technical solution for the aforementioned photovoltaic grid-connected cabinet, the filter box includes a filter chamber and a gas chamber that are connected. The gas chamber is connected to the interior of the cabinet, and the filter chamber is connected to the external environment. A desiccant is provided in the filter chamber, and the desiccant is used to dry the air entering the filter chamber.

[0021] As an optional technical solution for the aforementioned photovoltaic grid-connected cabinet, the desiccant includes silica gel desiccant.

[0022] As an optional technical solution for the aforementioned photovoltaic grid-connected cabinet, the top of the cabinet is provided with a canopy unit, and the edge of the canopy unit extends downward along a first direction with a drainage section, the cross-sectional shape of which is an inverted triangle.

[0023] As an optional technical solution for the aforementioned photovoltaic grid-connected cabinet, the canopy unit includes a cover plate, a top plate, and a side plate. The top plate covers the top of the cabinet body and protrudes circumferentially from the cabinet body. The edge of the top plate bends downward in a first direction and is connected to the edge of the cover plate through the side plate. The bent portion of the top plate and the side plate form the drainage section.

[0024] As an optional technical solution for the aforementioned photovoltaic grid-connected cabinet, the top of the cabinet is provided with a canopy unit, which includes a cover plate, a top plate, and a side plate. The top plate covers the top of the cabinet and has a heat dissipation vent that communicates with the inside of the cabinet. The top plate is connected to the edge of the cover plate circumferentially through the side plate. The top plate protrudes circumferentially from the cabinet, and the part of the top plate protruding from the cabinet is provided with a bridge membrane heat dissipation hole.

[0025] The beneficial effects of this invention are:

[0026] The photovoltaic grid-connected cabinet provided by this invention has a first circuit breaker located below the current transformer unit, a second circuit breaker arranged side-by-side with the first circuit breaker and also located below the current transformer unit, and a disconnecting switch located below the first circuit breaker. A power generation cable connects the photovoltaic power generation side and the second circuit breaker, and an outgoing cable connects the disconnecting switch and the power consumption side, enabling external cables connected to the photovoltaic grid-connected cabinet to enter and exit from the bottom of the cabinet. Furthermore, the disconnecting switch being located at the bottom of the cabinet shortens the length of the outgoing cable within the cabinet, does not occupy space within the cabinet, and allows the outgoing cable to be directly led into the grid-connected cabinet's basic unit without bending it. This eliminates the need to reserve space within the cabinet for bending cables, reducing the size of the photovoltaic grid-connected cabinet and consequently reducing the space it occupies. Attached Figure Description

[0027] Figure 1 is a front view of the photovoltaic grid-connected cabinet provided in an embodiment of the present invention;

[0028] Figure 2 is a left view of the photovoltaic grid-connected cabinet provided in an embodiment of the present invention;

[0029] Figure 3 is a right view of the photovoltaic grid-connected cabinet provided in an embodiment of the present invention;

[0030] Figure 4 is a rear view of the photovoltaic grid-connected cabinet provided in an embodiment of the present invention;

[0031] Figure 5 is an electrical connection circuit diagram of the current transformer unit, the first circuit breaker, the disconnecting switch and the second circuit breaker provided in an embodiment of the present invention;

[0032] Figure 6 is a schematic diagram of the external structure of the photovoltaic grid-connected cabinet provided in an embodiment of the present invention;

[0033] Figure 7 is a structural schematic diagram of the ceiling unit provided in an embodiment of the present invention;

[0034] Figure 8 is a schematic diagram of the structure of the protective cover of the air inlet filter device provided in an embodiment of the present invention covering the outside of the filter box;

[0035] Figure 9 is a schematic diagram of the structure of the air intake filter device provided in an embodiment of the present invention with the protective cover open.

[0036] In the picture:

[0037] 100. Generating cable; 200. Outgoing cable;

[0038] 1. Cabinet; 2. Instrument transformer unit; 3. First circuit breaker; 4. Disconnecting switch; 5. Second circuit breaker; 6. Grid-connected cabinet foundation unit; 7. Metering instrument unit; 8. Multifunctional measurement and control unit; 9. Ceiling unit; 10. Air inlet filter device;

[0039] 11. First chamber; 12. Second chamber; 13. Third chamber; 14. Water guide channel structure;

[0040] 21. Metering transformer;

[0041] 32. Current transformer;

[0042] 42. Disconnect switch handle;

[0043] 52. Multifunctional measurement and control instrument; 53. First busbar; 54. Second busbar; 55. Busbar; 551. First section; 552. Second section; 553. Third section;

[0044] 91. Cover plate; 92. Drainage section; 93. Top plate; 931. Heat dissipation vent; 94. Side plate; 95. Heat dissipation assembly; 951. Mounting plate; 952. Negative pressure axial flow fan; 96. Bridge membrane heat dissipation hole; 97. Fire prevention and extinguishing device;

[0045] 101. Filter box; 1011. Filter chamber; 1012. Gas chamber; 102. Desiccant; 103. Control components; 104. Drive components; 105. Protective cover. Detailed Implementation

[0046] The present invention will now be described in further detail with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are merely illustrative of the invention and not intended to limit it. Furthermore, it should be noted that, for ease of description, the accompanying drawings show only the parts relevant to the present invention, and not all of the structures.

[0047] In the description of this invention, unless otherwise explicitly specified and limited, the terms "connected," "linked," and "fixed" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral part; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; they can refer to the internal communication of two components or the interaction between two components. Those skilled in the art can understand the specific meaning of the above terms in this invention based on the specific circumstances.

[0048] In this invention, unless otherwise explicitly specified and limited, "above" or "below" the second feature can include direct contact between the first and second features, or contact between the first and second features through another feature between them. Furthermore, "above," "over," and "on top" of the second feature includes the first feature directly above or diagonally above the second feature, or simply indicates that the first feature is at a higher horizontal level than the second feature. "Below," "below," and "under" the second feature includes the first feature directly below or diagonally below the second feature, or simply indicates that the first feature is at a lower horizontal level than the second feature.

[0049] In the description of this embodiment, the terms "upper," "lower," "right," etc., refer to the orientation or positional relationship shown in the accompanying drawings. They are used only for ease of description and simplification of operation, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on the present invention. In addition, the terms "first" and "second" are used only for distinction in description and have no special meaning.

[0050] This embodiment provides a photovoltaic grid-connected cabinet for connecting the photovoltaic power generation side and the power consumption side. The photovoltaic grid-connected cabinet collects the current from the photovoltaic power generation side and transmits it to the power consumption side.

[0051] As shown in Figures 1 and 2, the photovoltaic grid-connected cabinet provided in this embodiment includes a cabinet 1. The cabinet 1 contains a current transformer unit 2, a first circuit breaker 3, a disconnecting switch 4, and at least one second circuit breaker 5. The current transformer unit 2 is located at the top of the cabinet 1 along a first direction. The current transformer unit 2 is used to measure the current data on the photovoltaic power generation side and is a dedicated component of the power bureau. The first circuit breaker 3 is located below the current transformer unit 2 along a first direction, which is the vertical direction of the cabinet 1. The disconnecting switch 4 is located below the first circuit breaker 3 along a first direction. The second circuit breaker 5 is located below the current transformer unit 2 along a first direction and is arranged side-by-side with the first circuit breaker 3 and the disconnecting switch 4 along a second direction, which is perpendicular to the first direction. The incoming terminal of the second circuit breaker 5 is used to connect to the power generation cable 100 on the photovoltaic power generation side. The outgoing terminal of the second circuit breaker 5 is connected to the incoming terminal of the first circuit breaker 3 via the busbar and the current transformer unit 2. The outgoing terminal of the first circuit breaker 3 is connected to the incoming terminal of the disconnecting switch 4. The outgoing terminal of the disconnecting switch 4 is used to connect to the outgoing cable 200 on the power consumption side.

[0052] At least one photovoltaic inverter is installed on the photovoltaic power generation side. The current converted by the photovoltaic inverter enters the second circuit breaker 5 through the power generation cable 100, and then flows through the current transformer unit 2, the first circuit breaker 3 and the disconnect switch 4 in sequence, and is then led out to the power consumption side through the outgoing cable 200. The photovoltaic grid-connected cabinet plays the role of combining the current on the photovoltaic power generation side.

[0053] When the photovoltaic grid-connected cabinet is installed on site, a grid-connected cabinet base unit 6 is set up on site, and the cabinet body 1 is set up above the grid-connected cabinet base unit 6. The grid-connected cabinet base unit 6 is used for the transmission cable 100 and the outgoing cable 200 to pass through. One end of the transmission cable 100 is used to connect to the photovoltaic power generation side, and the other end of the transmission cable 100 passes through the grid-connected cabinet base unit 6 and the cabinet body 1 and is connected to the second circuit breaker 5. One end of the outgoing cable 200 is connected to the disconnecting switch 4, and the other end of the outgoing cable 200 passes through the cabinet body 1 and the grid-connected cabinet base unit 6 in sequence and is used to connect to the power consumption side.

[0054] The first circuit breaker 3 is located below the current transformer unit 2. The second circuit breaker 5 is located side by side with the first circuit breaker 3 and below the current transformer unit 2. The disconnecting switch 4 is located below the first circuit breaker 3. The power generation cable 100 connects the photovoltaic power generation side and the second circuit breaker 5. The outgoing cable 200 connects the disconnecting switch 4 and the power consumption side, so that the external cable connected to the photovoltaic grid-connected cabinet can enter and exit from the bottom of the cabinet 1. The disconnecting switch 4 is located at the bottom inside the cabinet 1, which shortens the length of the outgoing cable 200 inside the cabinet 1 and does not occupy the space inside the cabinet 1. The outgoing cable 200 can be directly led into the grid-connected cabinet base unit 6 without bending the outgoing cable 200, and thus there is no need to reserve space for bending the cable inside the cabinet 1. This can reduce the size of the photovoltaic grid-connected cabinet and thus reduce the space occupied by the photovoltaic grid-connected cabinet.

[0055] The second direction mentioned above is perpendicular to the first direction, and the second direction is the width direction of cabinet 1.

[0056] Optionally, in the second direction, the first circuit breaker 3 and the disconnecting switch 4 are located at the front of the cabinet 1, and the second circuit breaker 5 is located at the rear of the cabinet 1.

[0057] Inside the cabinet 1, a first chamber 11 and a second chamber 12 are arranged sequentially from top to bottom along a first direction. The current transformer unit 2 is located in the first chamber 11, and the first circuit breaker 3, the disconnecting switch 4, and the second circuit breaker 5 are all located in the second chamber 12. An insulating epoxy board is used to separate the first chamber 11 and the second chamber 12 inside the cabinet 1, and the periphery of the insulating epoxy board is sealed to the inner wall of the cabinet 1 by a lead seal structure to comply with power grid metering standards.

[0058] In some embodiments, as shown in Figures 3 and 4, the instrument transformer unit 2 includes three metering instrument transformers 21, which are dedicated components of the power company. The three metering instrument transformers 21 correspond one-to-one with the three-phase outgoing terminals of the second circuit breaker 5. Each phase outgoing terminal of the second circuit breaker 5 is connected to a set of busbars, which pass through the corresponding metering instrument transformer 21. The photovoltaic inverters on the photovoltaic power generation side are also configured one-to-one with the second circuit breaker 5. The three-phase outgoing terminals of each photovoltaic inverter are connected to the three-phase incoming terminals of the corresponding second circuit breaker 5 via power generation cables 100. The three-phase outgoing terminals of the second circuit breaker 5 are connected to the corresponding busbars, which pass through the corresponding metering instrument transformers 21. The metering instrument transformers 21 measure current data.

[0059] In existing technologies, to improve the safety factor of photovoltaic grid-connected cabinets and facilitate circuit breaker connection, circuit breakers with reverse connection function are typically used, meaning the incoming and outgoing terminals of the circuit breaker can be interchanged. However, circuit breakers with reverse connection function are expensive and relatively rare. Therefore, to solve the above problems, in this embodiment, the incoming and outgoing terminals of each second circuit breaker 5 are arranged along a third direction, which is perpendicular to the first and second directions, where the third direction is the length direction of the cabinet 1. The three-phase incoming terminals of the second circuit breaker 5 are respectively used to connect to the power generation cable 100, and the three-phase outgoing terminals of the second circuit breaker 5 are connected to three sets of busbars. The second circuit breaker 5 is arranged laterally along the third direction, which facilitates the connection of the second circuit breaker 5 to the power generation cable 100 and the busbars, minimizes the bending or usage of the busbars, and does not occupy space within the cabinet 1. Furthermore, there is no need to use circuit breakers with reverse connection functions to meet the wiring requirements of the circuit breakers, thereby reducing the production cost of photovoltaic grid-connected cabinets, which is beneficial to the development of the photovoltaic industry, and the photovoltaic grid-connected cabinets have a high safety factor. In addition, in order to facilitate the connection of the power generation cable 100 to the incoming end of the second circuit breaker 5, copper busbars are connected to the incoming end of the second circuit breaker 5 respectively, and the power generation cable 100 is connected to the corresponding copper busbars.

[0060] The aforementioned second circuit breaker 5 can be a molded case circuit breaker or a miniature circuit breaker. The selected molded case circuit breaker meets the system voltage and current requirements based on the capacity of the photovoltaic inverter. Furthermore, the second circuit breaker 5 can be paired with current transformers, multi-functional measurement and control instruments 52, and other devices to monitor various electrical parameters of the branch circuits in real time.

[0061] Referring to Figure 3, the incoming terminal of the first circuit breaker 3 is positioned above the outgoing terminal along the first direction, and the three-phase incoming terminals of the first circuit breaker 3 are connected to the corresponding busbars. The metering transformer 21 is positioned above the first circuit breaker 3, and the incoming terminal of the first circuit breaker 3 also faces the metering transformer 21. This facilitates the connection of the busbar through the metering transformer 21 to the incoming terminal of the first circuit breaker 3, conforming to the wiring rule of the first circuit breaker 3 with incoming and outgoing lines. This ensures a high safety factor, eliminates the need for circuit breakers with reverse connection functions, and allows the use of a standard first circuit breaker 3 to meet the requirements, thus reducing the production cost of the photovoltaic grid-connected cabinet.

[0062] The first circuit breaker 3 can be either a molded case circuit breaker or a frame circuit breaker. The appropriate molded case circuit breaker must be selected based on the photovoltaic power generation capacity to meet the system voltage, current, and other functional requirements. Furthermore, the first circuit breaker 3 can be equipped with anti-islanding and electrically operated devices to ensure the safe operation of the photovoltaic grid-connected system.

[0063] In some embodiments, multiple second circuit breakers 5 are provided, and the multiple second circuit breakers 5 are spaced apart along a first direction. To facilitate wiring to the incoming and outgoing terminals of the second circuit breakers 5, the incoming terminals of each of the three phases of the second circuit breaker 5 are respectively connected to a first busbar 53, leading out the incoming terminals of the second circuit breaker 5, which facilitates the connection of the first busbar 53 to the power generation cable 100. The busbar includes a second busbar 54 and a busbar 55. The outgoing terminals of each of the three phases of the second circuit breaker 5 are respectively connected to a second busbar 54, leading out the outgoing terminals of the second circuit breaker 5. The second busbars 54 of the same phase of the multiple second circuit breakers 5 are connected in series through the busbar 55, so that the multiple currents on the power generation side are combined. The busbar 55 passes through the metering transformer 21 and is connected to the incoming terminal of the first circuit breaker 3.

[0064] Optionally, the first busbar 53 and the second busbar 54 extend along a second direction, and the busbar 55 includes a first section 551, a second section 552, and a third section 553 connected in sequence. The first section 551 extends along a first direction and is connected in series with the second busbar 54, allowing multiple second busbars 54 of the same phase of the second circuit breakers 5 arranged along the first direction to be connected in series. The second section 552 extends along the second direction and passes through the metering transformer 21, facilitating the passage of the design quantity transformer 21. The third section 553 is connected to the incoming terminal of the first circuit breaker 3. The above-described structure of the busbar 55 can achieve the connection of the first circuit breaker 3 and the second circuit breaker 5, and the passage of the design quantity transformer 21, while reducing the space occupied inside the cabinet 1.

[0065] The disconnector switch 4 is located below the first circuit breaker 3. The incoming terminal of the disconnector switch 4 is positioned above the outgoing terminal along a first direction, and the incoming terminal of the disconnector switch 4 is electrically connected to the outgoing terminal of the first circuit breaker 3. Optionally, the incoming terminal of the disconnector switch 4 can be connected to the outgoing terminal of the first circuit breaker 3 via a busbar. A current transformer 32 can also be installed between the disconnector switch 4 and the first circuit breaker 3, with one current transformer 32 corresponding to each phase of the first circuit breaker 3. The outgoing terminal of the disconnector switch 4 is connected to one end of the outgoing cable 200. The corresponding positioning of the incoming terminal of the disconnector switch 4 and the outgoing terminal of the first circuit breaker 3 facilitates wiring, conforms to the wiring rule of upper-in, lower-out wiring for the disconnector switch 4, has a high safety factor, eliminates the need for a disconnector switch 4 with reverse connection functionality, and allows the use of a standard disconnector switch 4 to meet the requirements, thus reducing the production cost of the photovoltaic grid-connected cabinet. Furthermore, since the outgoing cable 200 connected to the outgoing terminal of the disconnector switch 4 can be directly introduced into the grid-connected cabinet base unit 6, the amount of outgoing cable 200 used can be effectively reduced, the space occupied by the outgoing cable 200 in the cabinet 1 can be reduced, the space utilization rate in the cabinet 1 can be improved, and the construction cost can be reduced. The outgoing cable 200 can be directly introduced into the grid-connected cabinet base unit 6, avoiding the problem of the outgoing cable 200 requiring a large construction space due to the bending radius in the cabinet 1.

[0066] The disconnector switch 4 needs to be selected according to the photovoltaic power generation capacity to meet the system voltage, current and other functions. The disconnector switch 4 can also be connected to the disconnector switch handle 42, which is located on the outside of the cabinet 1, so that the user can open and close the disconnector switch 4 without opening the cabinet door of the cabinet 1.

[0067] The aforementioned grid-connected cabinet base unit 6 is located below the cabinet body 1. Both the generator cable 100 and the outgoing cable 200 need to pass through the cabinet body 1. Therefore, an inlet hole and an outlet hole are provided at the bottom of the cabinet body 1. The inlet hole is for the generator cable 100 to pass through, and the outlet hole is for the outgoing cable 200 to pass through. To improve the sealing of the cabinet body 1, waterproof glands or tower-shaped rubber rings can be installed at the inlet and outlet holes, and fireproof sealant can be used to seal them, preventing humid gases from entering the cabinet body 1 through the inlet and outlet holes.

[0068] In some embodiments, referring to Figures 3 and 4, a metering instrument unit 7 is also provided inside the cabinet 1. The metering instrument unit 7 is arranged at the top of the cabinet 1 along a first direction and is arranged side by side with the current transformer unit 2 along a second direction. The metering instrument unit 7 is used to measure and acquire the electrical energy data of the photovoltaic power generation side. The metering instrument unit 7 is used in conjunction with the current transformer unit 2. The metering instrument unit 7 includes professional metering instruments with remote data collection function, used to measure the electrical energy data of the photovoltaic power generation system. A third chamber 13 is arranged side by side with the first chamber 11 along the second direction inside the cabinet 1. The third chamber 13 is used to house the metering instrument unit 7. An insulating epoxy board is provided inside the cabinet 1 to separate the third chamber 13 from the first chamber 11 and the second chamber 12. The periphery of the insulating epoxy board is sealed to the inner wall of the cabinet 1 by a lead seal structure to comply with the power grid metering standards.

[0069] Along the first direction, a multi-functional monitoring and control unit 8 is located below the second circuit breaker 5 and the disconnecting switch 4. The multi-functional monitoring and control unit 8 includes at least one of the following: an anti-islanding device, a power quality detection device, a multi-functional instrument, and an electrical control device. Different devices can be configured according to usage requirements to meet various electrical parameters within the photovoltaic grid-connected cabinet, as well as environmental parameters such as temperature and humidity, thus satisfying the human-machine interaction needs of electrical operation and maintenance. The multi-functional monitoring and control unit 8 is used in conjunction with the current transformer 32.

[0070] The aforementioned anti-islanding protection device is a protective device used to prevent distributed power sources from losing connection with the grid and forming islands. It mainly targets islanding caused by voltage or frequency anomalies on the photovoltaic power generation side. After the distributed photovoltaic system is equipped with the anti-islanding protection device, when either the power consumption side or the photovoltaic power generation side loses power, the anti-islanding device will quickly send a trip signal to the circuit breaker in the photovoltaic grid-connected cabinet, causing the circuit breaker to open. This ensures the safety of maintenance personnel on both sides of the photovoltaic system and solves the islanding problem in the photovoltaic power station.

[0071] Power quality testing devices are used to measure and analyze the AC power quality from the generation side to the consumption side. The indicators they measure and analyze include: power supply frequency deviation, power supply voltage deviation, power supply voltage fluctuation and flicker, allowable unbalance of three-phase power supply voltage, grid harmonics, application of wavelet transform to measure and analyze harmonics of non-stationary time-varying signals, and measurement and analysis of the impact of various electrical devices on the power quality of the public power grid under different operating conditions.

[0072] The multi-functional instrument has functions such as power measurement, multi-rate power metering, four-quadrant power metering, harmonic analysis, remote signaling input, remote control output, SOE event recording, and network communication. It is mainly used for comprehensive monitoring and diagnosis of power supply quality and power management of related systems at the grid connection point.

[0073] The electrical control device works in conjunction with the anti-islanding device to monitor the operating status of the grid-connected cabinet, parameters such as temperature and humidity inside the cabinet, and can display them on the screen. This meets the human-machine interaction needs of electrical operation and maintenance, and can also control the opening and closing of the grid-connected cabinet and provide fault alarms.

[0074] As shown in Figure 5, each second circuit breaker 5 is connected to a photovoltaic inverter. The three-phase output terminals of each photovoltaic inverter are connected to the three-phase input terminals of the corresponding second circuit breaker 5 through the power generation cable 100. The same phases of multiple second circuit breakers 5 are connected to achieve current collection. The current collection busbar 55 then passes through the corresponding metering transformer 21 and is connected to the three-phase input terminals of the first circuit breaker 3. The three-phase output terminals of the first circuit breaker 3 are respectively connected to transformers 32 and then connected to the disconnecting switch 4. The output cable 200 is connected to the disconnecting switch 4, thereby collecting and diverting the current from the photovoltaic power generation side to the power consumption side.

[0075] The busbars mentioned above can be cables or busbars, and their materials can be copper or aluminum, without specific limitations.

[0076] As shown in Figure 6, the photovoltaic grid-connected cabinet is installed outdoors. To improve the protection level of the photovoltaic grid-connected cabinet, a canopy unit 9 is installed on the top of the cabinet. The edge of the canopy unit 9 extends downward along the first direction with a drainage section 92. The cross-sectional shape of the drainage section 92 is an inverted triangle. Rainwater falling on the canopy unit 9 can fall from the apex of the drainage section 92, preventing it from flowing into the inner side of the canopy unit 9 to the surface of the cabinet 1 due to the gravity of the water flow and the surface tension of the water flow. In the prior art, the part of the cabinet door that contacts the cabinet body is usually provided with a water guide channel structure 14, and the part of the door that contacts the cabinet body is also provided with a sealing strip. Rainwater on the top of the cabinet 1 is discharged downward through the water guide channel structure 14. However, the water guide channel structure 14 has a limited load-bearing capacity. When the water volume is too large, rainwater will seep into the cabinet 1 through the sealing strip, causing the protection to fail. Therefore, in this embodiment, a drainage part 92 is provided on the ceiling 9, which can change the direction of rainwater flow, reduce the load-bearing pressure of the water guide channel structure 14, and improve the protection capability of the photovoltaic grid-connected cabinet.

[0077] Optionally, as shown in Figure 7, the canopy unit 9 includes a cover plate 91, a top plate 93, and a side plate 94. The top plate 93 covers the top of the cabinet and is connected to the edge of the cover plate 91 circumferentially through the side plate 94. The top plate 93, side plate 94, and cover plate 91 form a cavity. A drainage section 92 is provided along the circumferential edge of the top plate 93 and protrudes from the top plate 93 in a first direction. The cover plate 91 can be a conical structure to guide rainwater falling onto the cover plate 91 and prevent rainwater from accumulating on the cover plate 91 and increasing the pressure on the cabinet 1.

[0078] The top plate 93 protrudes circumferentially from the cabinet 1. The edge of the top plate 93 bends downward in a first direction and is connected to the edge of the cover plate 91 via a side plate 94. The bent portion of the top plate 93 and the side plate 94 form a drainage section 92. The structure is simple and easy to process and assemble. Optionally, the edge of the top plate 93 is inclined towards the side away from the cabinet 1, and the side plate 94 extends downward in the first direction to connect with the edge of the top plate 93, forming a drainage section 92 with a right-angled triangular cross-section, so that water flows downward and prevents water from flowing towards the cabinet 1.

[0079] The top plate 93 is provided with a heat dissipation vent 931 that communicates with the cabinet 1. Specifically, the top of the cabinet 1 is open, and the top plate 93 is connected to the top of the cabinet 1 and closes the opening. The top plate 93 protrudes circumferentially from the cabinet 1, and the portion of the top plate 93 protruding from the cabinet 1 is provided with a bridge membrane heat dissipation hole 96. Hot air inside the cabinet 1 flows into the ceiling unit 9 through the heat dissipation vent 931, and then is discharged to the external environment through the bridge membrane heat dissipation hole 96, thus achieving heat dissipation inside the cabinet 1. In addition, the bridge membrane heat dissipation hole 96 also improves the sealing performance of the cabinet 1, preventing dust and other impurities from entering the ceiling unit 9 through the bridge membrane heat dissipation hole 96 and then entering the cabinet 1 through the heat dissipation vent 931.

[0080] A heat dissipation component 95 is detachably installed at the heat dissipation vent 931 of the top plate 93. The heat dissipation component 95 is used to extract air from the cabinet 1. The heat dissipation component 95 can be activated according to the temperature inside the cabinet 1. When the temperature inside the cabinet 1 is higher than a preset temperature value, the heat dissipation component 95 is activated to extract air from the cabinet 1, realizing the circulation of air inside the cabinet 1 and ensuring that the temperature inside the cabinet 1 meets the requirements. The air extracted by the heat dissipation component 95 enters the cavity enclosed by the top plate 93, side plate 94 and cover plate 91, and is discharged to the external environment through the bridge membrane heat dissipation hole 96, thereby realizing the heat dissipation of the cabinet 1.

[0081] The heat dissipation holes 96 on the top plate 93 are arranged around the circumference of the cabinet 1 to improve heat dissipation efficiency. The top plate 93 is rectangular, and the cover plate 91 is a four-sided pyramid structure. Several heat dissipation holes 96 are formed on each edge of the top plate 93. The heat dissipation holes 96 are elongated holes, and multiple heat dissipation holes 96 are arranged in parallel along the edge of the top plate 93. The top plate 93 is connected to the cabinet 1 by welding to ensure the airtightness of the cabinet 1.

[0082] The heat dissipation component 95 is detachable from the top plate 93. Optionally, the heat dissipation component 95 includes a mounting plate 951, which is detachably mounted at the heat dissipation holes of the top plate 93. The mounting plate 951 is equipped with a negative pressure axial flow fan 952, which can exhaust the air inside the cabinet 1 to the outside of the cabinet 1 to ensure that the temperature inside the cabinet 1 meets the requirements.

[0083] Optionally, a fire suppression device 97 is provided on the side of the top plate 93 facing the interior of the cabinet 1. The fire suppression device 97 monitors the fire situation inside the cabinet 1 and can extinguish the fire. The fire suppression device 97 is communicatively connected to the fire monitoring backend of the livestock farm area. The fire suppression device 97 can transmit the monitored fire signal to the fire monitoring backend, which can then control the fire suppression device 97 to extinguish the fire. The fire suppression device 97 can also automatically perform fire extinguishing operations. The structure of the fire suppression device 97 and its communication structure with the fire monitoring backend are existing technologies and will not be described in detail here.

[0084] This photovoltaic grid-connected cabinet can be applied to livestock farms. Due to the special environment of livestock farms, the photovoltaic grid-connected cabinet is placed in an environment full of chlorine, ammonia, and other particles, especially under high humidity conditions, which can form highly corrosive acidic and alkaline substances. When the air inside the photovoltaic grid-connected cabinet exchanges with the air in the external environment, air carrying acidic and alkaline substances enters the cabinet 1, causing corrosion to the components inside the cabinet 1, thereby affecting the normal operation and service life of the photovoltaic grid-connected cabinet. To solve the above problems, as shown in Figures 4, 8, and 9, in one embodiment, at least one air intake filter 10 is provided on the outside of the cabinet 1 to filter out acidic and alkaline substances in the air. The air intake filtration device 10 includes a filter box 101, a control component 103, a drive component 104, and a protective cover 105. The filter box 101 is mounted on the cabinet 1, and the protective cover 105 covers the outside of the filter box 101. The protective cover 105 has an air inlet. The drive component 104 is connected to the protective cover 105. The control component 103 controls the drive component 104 to open or close the protective cover 105 over the filter box 101. When the control component 103 controls the drive component 104 to open the protective cover 105, the filter box 101 can be exposed to sunlight. During normal air filtration, the control component 103 controls the drive component 104 to close the protective cover 105 over the outside of the filter box 101, and air enters the filter box 101 through the air inlet on the protective cover 105.

[0085] The filter box 101 includes a filter chamber 1011 and a gas chamber 1012 that are connected to each other. The gas chamber 1012 is connected to the interior of the cabinet 1, while the filter chamber 1011 is connected to the external environment. A desiccant 102 is provided in the filter chamber 1011 to dry the air entering the filter chamber. After being dried by the desiccant in the filter chamber 1011, the outside air enters the gas chamber 1012, preventing acidic substances from entering the gas chamber 1012 and the interior of the cabinet 1. The gas chamber 1012 acts as a buffer for the filtered gas.

[0086] Optionally, the desiccant 102 includes silica gel desiccant, which is reusable and can filter acidic or alkaline substances in the air. Under normal use, the desiccant 102 is in an effectively dry state. When the desiccant 102 is saturated and cannot be effectively dried, air-drying the desiccant 102 allows for its reuse. To avoid removing the desiccant 102 for air-drying, in some embodiments, the sidewall of the filter chamber 1011 of the filter box 101 is made into a grid structure. When the desiccant 102 is in an undryable state, the control component 103 controls the drive component 104 to open the protective cover 105, exposing the desiccant 102 to sunlight. During normal air filtration, the control component 103 controls the drive component 104 to cover the outside of the filter box 101, and air enters the filter box 101 through the air inlet on the protective cover 105.

[0087] The control component 103 includes a controller that controls the operation of the drive component 104. The control component 103 may also include temperature, humidity, light intensity, and airflow sensors, which detect external temperature, humidity, light intensity, and airflow to determine if the external environment meets the conditions for drying the desiccant 102. If it does, the drive component 104 is controlled to open the protective cover 105. Drying the desiccant 102 can be performed periodically. After the desiccant 102 has been used for a preset time and the external environment meets the drying conditions, the protective cover 105 is opened to allow the desiccant 102 to dry. The structure of the control component 103 and the communication connection between the control component 103 and the drive component 104 are existing technologies and will not be described in detail here.

[0088] Optionally, one end of the protective cover 105 is rotatably connected to the filter box 101, and the driving member 104 is connected to one end of the protective cover 105. The driving member 104 can drive the protective cover 105 to rotate about the axis rotatably connected to the filter box 101. The driving member 104 can be a hydraulic rod, which extends out to drive the protective cover 105 to cover the outside of the filter box 101, and retracts to drive the protective cover 105 to open.

[0089] Obviously, the above embodiments of the present invention are merely examples for clearly illustrating the present invention, and are not intended to limit the implementation of the present invention. Those skilled in the art will be able to make various obvious changes, readjustments, and substitutions without departing from the scope of protection of the present invention. It is neither necessary nor possible to exhaustively describe all embodiments here. Any modifications, equivalent substitutions, and improvements made within the spirit and principles of the present invention should be included within the scope of protection of the claims of the present invention.

Claims

1. A photovoltaic grid-connected cabinet, characterized in that, include: Cabinet (1); current transformer unit (2), disposed at the top of the cabinet (1) along a first direction; first circuit breaker (3), disposed below the current transformer unit (2) along a first direction, with the input end of the first circuit breaker (3) disposed above the output end along a first direction, the first direction being the vertical direction of the cabinet (1); disconnector switch (4), disposed below the first circuit breaker (3) along a first direction, with the input end of the disconnector switch (4) disposed above the output end along a first direction; multiple second circuit breakers (5), multiple second circuit breakers (5) are spaced apart along a first direction, disposed below the current transformer unit (2) along a first direction, and arranged side by side with the first circuit breaker (3) and the disconnector switch (4) along a second direction, with the input and output ends of the second circuit breakers (5) arranged along a third direction, the third direction, the first direction and the second direction being perpendicular to each other; the current transformer unit (2) includes three Metering transformers (21), the three metering transformers (21) correspond one-to-one with the three-phase output terminals of the second circuit breaker (5); wherein, the output terminal of each phase of the second circuit breaker (5) is connected to a set of busbars, the busbars include a second busbar (54) and a busbar (55), the output terminals of the three phases of each second circuit breaker (5) are respectively connected to the second busbar (54), the second busbars (54) of the same phase of multiple second circuit breakers (5) are connected in series through the busbar (55), the busbar (55) passes through the corresponding metering transformers (21) and is connected to the input terminal of the first circuit breaker (3), the input terminal of the second circuit breaker (5) is used to connect to the power generation cable (100) on the photovoltaic power generation side, the output terminal of the first circuit breaker (3) is connected to the input terminal of the disconnect switch (4), the output terminal of the disconnect switch (4) is used to connect to the output cable (200) on the power consumption side.

2. The photovoltaic grid-connected cabinet according to claim 1, characterized in that, Each of the three phases of the second circuit breaker (5) is connected to a first busbar (53), which is used to connect to the power generation cable (100).

3. The photovoltaic grid-connected cabinet according to claim 2, characterized in that, The first busbar (53) and the second busbar (54) extend along the second direction respectively. The busbar (55) includes a first section (551), a second section (552) and a third section (553) connected in sequence. The first section (551) extends along the first direction and is connected in series with the second busbar (54). The second section (552) extends along the second direction and passes through the metering transformer (21). The third section (553) is connected to the incoming terminal of the first circuit breaker (3).

4. The photovoltaic grid-connected cabinet according to any one of claims 1-3, characterized in that, At least one air intake filter device (10) is provided on the outside of the cabinet (1). The air intake filter device (10) includes a filter box (101), a control component (103), a drive component (104), and a protective cover (105). The filter box (101) is disposed on the cabinet (1). The protective cover (105) is disposed on the outside of the filter box (101). The protective cover (105) is provided with an air intake hole. The drive component (104) is connected to the protective cover (105). The control component (103) is used to control the drive component (104) to drive the protective cover (105) to open or to be disposed on the outside of the filter box (101).

5. The photovoltaic grid-connected cabinet according to claim 4, characterized in that, The filter box (101) includes a filter chamber (1011) and a gas chamber (1012) that are connected. The gas chamber (1012) is connected to the interior of the cabinet (1). The filter chamber (1011) is connected to the external environment. The filter chamber (1011) is provided with a desiccant (102) for drying the air entering the filter chamber (1011).

6. The photovoltaic grid-connected cabinet according to claim 5, characterized in that, The desiccant (102) includes silica gel desiccant.

7. The photovoltaic grid-connected cabinet according to any one of claims 1-3, characterized in that, The top of the cabinet (1) is provided with a canopy unit (9), and the edge of the canopy unit (9) extends downward along the first direction with a drainage part (92), the cross-sectional shape of the drainage part (92) is an inverted triangle.

8. The photovoltaic grid-connected cabinet according to claim 7, characterized in that, The canopy unit (9) includes a cover plate (91), a top plate (93) and a side plate (94). The top plate (93) covers the top of the cabinet (1). The top plate (93) protrudes circumferentially from the cabinet (1). The edge of the top plate (93) bends downward in a first direction and is connected to the edge of the cover plate (91) through the side plate (94). The bent part of the top plate (93) and the side plate (94) form the drainage part (92).

9. The photovoltaic grid-connected cabinet according to any one of claims 1-3, characterized in that, The top of the cabinet (1) is provided with a canopy unit (9), which includes a cover plate (91), a top plate (93) and a side plate (94). The top plate (93) covers the top of the cabinet (1). The top plate (93) is provided with a heat dissipation vent (931) communicating with the inside of the cabinet (1). The top plate (93) is connected to the edge of the cover plate (91) circumferentially through the side plate (94). The top plate (93) protrudes circumferentially from the cabinet (1). The part of the top plate (93) protruding from the cabinet (1) is provided with a bridge membrane heat dissipation hole (96).

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