120kw automatic grid-connected and off-grid switching cabinet optical storage system

Abstract

The utility model relates to the field of parallel and off -grid switching technology discloses a 120kW automatic parallel and off -grid switching cabinet light storage system, including the grid side loop, the grid side loop includes static transfer switch, and static transfer switch outgoing line end connects equipment branch, energy storage system loop and light storage system loop respectively. The above technical scheme improves the reliability of the system through the redundant design of the energy storage cabinet and the photovoltaic inverter, ensures that the system can still operate normally when single equipment fails, and the multi-mode switching cooperates with the redundant design, ensuring that the product adapts to complex power grid environment and extreme scene demand.

Description

Technical Field

[0001] This utility model relates to the field of grid-connected and off-grid switching technology, and in particular to a 120kW automatic grid-connected and off-grid switching cabinet optical storage system. Background Technology

[0002] In power systems, grid-connected and off-grid switching cabinets are used to ensure uninterrupted operation of loads. Supplying power to the load through the main grid is called grid-connected, while supplying power through backup power sources such as energy storage systems is called off-grid. The grid-connected and off-grid switching cabinet achieves grid-connected / off-grid switching control by installing frame circuit breakers with mutually exclusive switching states between the power grid and the energy storage converter (PCS, an important component of the energy storage system).

[0003] Data shows that the current technology in the field of grid-connected and off-grid switching cabinets mainly focuses on achieving reliable switching between the power grid and independent power sources (such as diesel generators, small wind turbines, etc.) to ensure uninterrupted power supply to critical loads during grid failures or power outages. However, with the rapid development of renewable energy and the increasing demand for energy management, existing grid-connected and off-grid switching cabinet systems still need improvement in terms of functionality and integration, slow switching speed, redundancy and scalability, and security.

[0004] Chinese patent document CN120222473A discloses a "parallel-to-offline switching control circuit and parallel-to-offline switching cabinet". This circuit uses a parallel-to-offline switching control circuit to achieve manual operation by the user via buttons, controlling the opening and closing of any controlled frame circuit breaker in the parallel-to-offline switching cabinet. A detection unit detects whether there is power on the local AC bus of the parallel-to-offline switching cabinet to determine whether the other frame circuit breaker has already opened before closing. If the other frame circuit breaker has not opened, the controlled frame circuit breaker is automatically locked, preventing it from closing. Even if the user misoperates, the controlled frame circuit breaker will not actually close. However, the components in this technical solution are relatively independent, lacking modular design, and the switching speed is slow. Utility Model Content

[0005] This utility model mainly solves the technical problems of relatively independent components, lack of modular design, and slow switching speed in the original technical solution. It provides a 120kW automatic grid-connected and off-grid switching cabinet photovoltaic-storage system. The system reliability is improved by the redundant design of the energy storage cabinet and photovoltaic inverter, ensuring that the system can still operate normally when a single device fails. The multi-mode switching combined with the redundant design ensures that the product can adapt to complex power grid environments and extreme scenario requirements.

[0006] The above-mentioned technical problems of this utility model are mainly solved by the following technical solution: This utility model includes a grid-side circuit, the grid-side circuit includes a static transfer switch, and the output terminals of the static transfer switch are respectively connected to the equipment branch, the energy storage system circuit and the photovoltaic-storage system circuit.

[0007] Compared to traditional grid-connected and off-grid switching cabinet systems, this application consists of one main circuit and three branch circuits. The switching cabinet highly integrates various components such as meters, sensors, STS static transfer switches, AC miniature circuit breakers, AC circuit breakers, and molded case circuit breakers, resulting in a more compact overall design. This not only saves space but also reduces the need for additional cabinets. Furthermore, in terms of functionality, this product highly integrates the AC circuit breakers controlling the main circuit and branch circuits into the same switching cabinet, enabling multi-energy coordinated control through a single cabinet. The system is also equipped with sensors and meters, achieving integrated core functions such as energy metering, real-time monitoring, rapid switching, and safety protection; thus improving the product's functionality and level of integration.

[0008] Preferably, the grid-side circuit includes a static transfer switch, with its output terminals connected to the equipment branch, the energy storage system circuit, and the photovoltaic-storage system circuit, respectively. The 120kW automatic grid-connected / off-grid switching cabinet's photovoltaic-storage system is connected to the MCCB1 molded case circuit breaker's input terminal via 380V three-phase AC power. The MCCB1 molded case circuit breaker's output terminal is connected to the current transformer CT1's input terminal and the electricity meter PJ1. The current transformer CT's output terminal is connected to the static transfer switch STS module U / V / W grid side.

[0009] Preferably, the equipment branch includes a second current transformer and a load-side energy meter. The input terminal of the second current transformer is connected to the output terminal of the static transfer switch, and the output terminal of the second current transformer is connected to the client equipment circuit and other equipment circuits respectively.

[0010] Preferably, the client-side equipment circuit includes a backup AC circuit breaker. The incoming terminal of the backup AC circuit breaker is connected to the outgoing terminal of the static transfer switch (STS), and the outgoing terminal of the backup AC circuit breaker is connected to the client-side equipment. A circuit from the A / B / C leads of the load terminal of the static transfer switch (STS) module is connected to the incoming terminal of the MCCB4 molded case circuit breaker, and the outgoing terminal of the MCCB4 molded case circuit breaker is connected to the client-side equipment.

[0011] Preferably, the other equipment circuits include a first AC miniature circuit breaker, a second AC miniature circuit breaker, and a third AC miniature circuit breaker. The input terminals of the first, second, and third AC miniature circuit breakers are connected to the output terminals of the static transfer switch, and the output terminals are respectively connected to other equipment including a cooling fan and a temperature sensor. The A / B / C lead-out circuits of the static transfer switch STS module load terminal are respectively connected to the input terminals of the MCB1~3 AC miniature circuit breakers, and the output terminals of the MCB1~3 AC miniature circuit breakers are connected to other equipment such as cooling fans or temperature sensors.

[0012] Preferably, the energy storage system circuit includes an energy storage AC circuit breaker. The incoming terminal of the energy storage AC circuit breaker is connected to the outgoing terminal of a static transfer switch, and the outgoing terminal of the energy storage AC circuit breaker is connected to the air-cooled system energy storage cabinet. Branch line two of the A / B / C outgoing terminals of the static transfer switch STS module load terminal is connected to the incoming terminal of the MCCB2 AC circuit breaker, and the outgoing terminal of the MCCB2 AC circuit breaker is connected to the 115kWh air-cooled system energy storage cabinet.

[0013] Preferably, the photovoltaic-storage system circuit includes a photovoltaic AC circuit breaker. The input terminal of the photovoltaic AC circuit breaker is connected to the output terminal of a static transfer switch (STS). The output terminal of the photovoltaic AC circuit breaker is connected to a photovoltaic system consisting of a photovoltaic inverter and photovoltaic modules. The third branch of the A / B / C output terminal of the load side of the static transfer switch (STS) module is connected to the input terminal of the MCCB3 AC circuit breaker. The output terminal of the MCCB3 AC circuit breaker is connected to a photovoltaic system consisting of a 50kW photovoltaic inverter (INV) and photovoltaic modules.

[0014] Preferably, the system also includes a power-on alarm indicator, a running alarm indicator, and an emergency stop button located on the grid-connected / off-grid switching cabinet. The power-on alarm indicator displays the power-on alarm fault status, the running alarm indicator displays the running alarm fault status, and when an abnormality occurs, pressing the emergency stop button will stop the grid-connected / off-grid switching cabinet from operation.

[0015] Preferably, the system also includes a first grounding point and a second grounding point respectively located on the front and rear sides of the grid-connected switching cabinet. These serve as electrical connection points between the grid-connected switching cabinet and the earth, thus providing grounding protection for the switching cabinet.

[0016] Preferably, the air-cooled system circuit includes a first cooling fan and a second cooling fan installed on the inner wall of the grid-connected switching cabinet. The first cooling fan and the second cooling fan remove heat from the heat-generating components inside the cabinet.

[0017] The beneficial effects of this utility model are: the system dynamically adjusts the power source according to actual power demand, weather conditions or electricity price fluctuations, thereby improving the redundancy and scalability of the product.

[0018] In terms of safety, the system is equipped with a triple protection mechanism: miniature circuit breaker (overcurrent) + molded case circuit breaker (short circuit) + STS protection (built-in overvoltage / undervoltage, overfrequency / underfrequency protection); it can cut off the circuit in time when the equipment fails or is overloaded, protecting the equipment and personnel safety.

[0019] Meanwhile, the redundant design of the energy storage cabinet and photovoltaic inverter improves system reliability, ensuring that the system can still operate normally in the event of a single device failure. Multi-mode switching and redundancy design ensure that the product can adapt to complex power grid environments and extreme scenario requirements. Attached Figure Description

[0020] Figure 1This is a circuit principle connection structure diagram of this utility model.

[0021] Figure 2 This is a schematic diagram of the front structure of a 120KW automatic grid-connected / off-grid switching cabinet according to this utility model.

[0022] Figure 3 This is a schematic diagram of the back structure of a 120KW automatic grid-connected / off-grid switching cabinet according to this utility model.

[0023] In the diagram, 1 is the grid-side energy meter, 2 is the load-side energy meter, 3 is the first 6P terminal block, 4 is the second 6P terminal block, 5 is the power-on alarm indicator, 6 is the operation alarm indicator, 7 is the emergency stop button, 8 is the first current transformer, 9 is the photovoltaic AC circuit breaker, 10 is the energy storage AC circuit breaker, 11 is the first AC miniature circuit breaker, 12 is the second AC miniature circuit breaker, 13 is the third AC miniature circuit breaker, 14 is the static transfer switch, 15 is the second current transformer, 16 is the standby AC circuit breaker, 17 is the grid-side AC circuit breaker, 18 is the first cooling fan, 19 is the second cooling fan, 20 is the first grounding point, and 21 is the second grounding point. Detailed Implementation

[0024] To make the objectives, technical solutions, and advantages of this invention clearer, the technical solutions of this application will be further described in detail below through embodiments and in conjunction with the accompanying drawings. It should be understood that the specific embodiments described herein are only one preferred embodiment of this application and are only used to explain this application. They do not limit the scope of protection of this application. All other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of this invention.

[0025] The technical solution of this utility model will be further described in detail below through embodiments and in conjunction with the accompanying drawings.

[0026] Example: This example describes a 120kW automatic grid-connected / off-grid switching cabinet photovoltaic-storage system, such as... Figure 1 As shown, it includes a grid-side circuit, which includes a static transfer switch (14). The output terminals of the static transfer switch (14) are respectively connected to the equipment branch, the energy storage system circuit and the photovoltaic-storage system circuit.

[0027] Compared to traditional grid-connected and off-grid switching cabinet systems, this application consists of one main circuit and three branch circuits. The switching cabinet highly integrates various components such as meters, sensors, STS static transfer switches, AC miniature circuit breakers, AC circuit breakers, and molded case circuit breakers, resulting in a more compact overall design. This not only saves space but also reduces the need for additional cabinets. Furthermore, in terms of functionality, this product highly integrates the AC circuit breakers controlling the main circuit and branch circuits into the same switching cabinet, enabling multi-energy coordinated control through a single cabinet. The system is also equipped with sensors and meters, achieving integrated core functions such as energy metering, real-time monitoring, rapid switching, and safety protection; thus improving the product's functionality and level of integration.

[0028] The grid-side circuit includes a static transfer switch (14), whose output terminals are connected to the equipment branch, the energy storage system circuit, and the photovoltaic-storage system circuit, respectively. The 120kW automatic grid-connected switching cabinet photovoltaic-storage system is connected to the input terminal of the MCCB1 molded case circuit breaker via 380V three-phase AC power. The output terminal of the MCCB1 molded case circuit breaker is connected to the input terminal of the current transformer CT1 and the meter PJ1. The output terminal of the current transformer CT is connected to the grid side of the static transfer switch STS module U / V / W.

[0029] The equipment branch includes a second current transformer (15) and a load-side energy meter. The input terminal of the second current transformer (15) is connected to the output terminal of the static transfer switch (14). The output terminal of the second current transformer (15) is connected to the client equipment circuit and other equipment circuits respectively. The client equipment circuit includes a standby AC circuit breaker (16). The input terminal of the standby AC circuit breaker (16) is connected to the output terminal of the static transfer switch (14). The output terminal of the standby AC circuit breaker (16) is connected to the client's required equipment. The A / B / C lead-out circuit of the load terminal of the static transfer switch STS module is connected to the input terminal of the MCCB4 molded case circuit breaker. The output terminal of the MCCB4 molded case circuit breaker is connected to the client's required equipment. Other equipment circuits include a first AC miniature circuit breaker (11), a second AC miniature circuit breaker (12), and a third AC miniature circuit breaker (13). The input terminals of the first AC miniature circuit breaker (11), the second AC miniature circuit breaker (12), and the third AC miniature circuit breaker (13) are connected to the output terminals of a static transfer switch (14), and the output terminals are respectively connected to other equipment including cooling fans and temperature sensors. The A / B / C lead-out circuits of the load terminals of the static transfer switch STS module are respectively connected to the input terminals of the MCB1~3 AC miniature circuit breakers, and the output terminals of the MCB1~3 AC miniature circuit breakers are connected to other equipment such as cooling fans or temperature sensors.

[0030] The energy storage system circuit includes an energy storage AC circuit breaker (10). The incoming terminal of the energy storage AC circuit breaker (10) is connected to the outgoing terminal of the static transfer switch (14), and the outgoing terminal of the energy storage AC circuit breaker (10) is connected to the air-cooled system energy storage cabinet. The second branch of the A / B / C outgoing terminal of the load terminal of the static transfer switch STS module is connected to the incoming terminal of the MCCB2 AC circuit breaker, and the outgoing terminal of the MCCB2 AC circuit breaker is connected to the 115kWh air-cooled system energy storage cabinet.

[0031] The photovoltaic-storage system circuit includes a photovoltaic AC circuit breaker (9). The input terminal of the photovoltaic AC circuit breaker (9) is connected to the output terminal of the static transfer switch (14). The output terminal of the photovoltaic AC circuit breaker (9) is connected to the photovoltaic system composed of a photovoltaic inverter and photovoltaic modules. The three output branches of the load terminal A / B / C of the static transfer switch STS module are connected to the input terminal of the MCCB3 AC circuit breaker. The output terminal of the MCCB3 AC circuit breaker is connected to the photovoltaic system composed of a 50kW photovoltaic inverter INV and photovoltaic modules.

[0032] like Figure 2 , Figure 3 As shown, the system also includes a power-on alarm indicator, a running alarm indicator, and an emergency stop button located on the grid-connected switching cabinet. The power-on alarm indicator displays the power-on alarm fault status, and the running alarm indicator displays the running alarm fault status. When an abnormality occurs, pressing the emergency stop button will stop the grid-connected switching cabinet. The system also includes a first grounding point and a second grounding point located on the front and rear sides of the grid-connected switching cabinet, respectively. These serve as electrical connection points between the grid-connected switching cabinet and the earth, providing grounding protection for the switchgear. The air-cooling system circuit includes a first cooling fan and a second cooling fan located on the inner wall of the grid-connected switching cabinet. The first and second cooling fans remove heat from the heat-generating components inside the cabinet. Example 2

[0033] Compared to traditional grid-connected and off-grid switching cabinet systems, this product consists of one main circuit and three branch circuits. The switching cabinet highly integrates various components such as meters, sensors, STS static transfer switches, AC miniature circuit breakers, AC circuit breakers, and molded case circuit breakers, resulting in a more compact overall design. This not only saves space but also reduces the need for additional cabinets. Furthermore, in terms of functionality, this product highly integrates the AC circuit breakers controlling the main circuit and branch circuits into the same switching cabinet, enabling multi-energy coordinated control through a single cabinet. The system is also equipped with sensors and meters, achieving integrated core functions such as energy metering, real-time monitoring, rapid switching, and safety protection; thus improving the product's functionality and level of integration.

[0034] In terms of switching and response speed, this product adopts STS static transfer switch. Compared with traditional manual switching, mechanical switching relies on manual operation or electromagnetic relays. Through millisecond-level switching speed and intelligent response strategy, it achieves an order-of-magnitude improvement in switching and response speed, ensuring "zero interruption" of critical loads, reducing downtime losses, and adapting to high-reliability power supply scenarios.

[0035] Meanwhile, the on-grid and off-grid switching cabinet adopts a highly integrated design, which can be uniformly managed and monitored through the same switching cabinet. When the main STS module fails, the backup module can seamlessly take over. While ensuring uninterrupted operation of the load, it greatly reduces the time required for manual troubleshooting and path switching, which helps to improve the system's coordination and response speed.

[0036] Regarding redundancy and scalability, the STS module supports N+1 redundancy configuration and adopts multiple power path backup. The main circuit serves as the core power supply channel, with one of the three branches serving as the primary power supply and the other two as backups. This ensures that there are still two levels of redundancy support even if a single branch fails. When the main circuit power supply fails, the system can automatically or manually switch to any branch power supply to avoid power interruption.

[0037] In terms of scalability, the product achieves seamless switching between multiple modes: "automatic", "grid-connected to off-grid", and "off-grid to grid-connected" modes.

[0038] Grid-connected mode: In this mode, as long as the mains power is normal, the STS module is in grid-connected state by default. During the day, the grid supplies power to the energy storage cabinet and the load; the photovoltaic side supplies power to the energy storage cabinet and the load, and the energy storage cabinet replenishes power to the grid; the energy storage cabinet receives power from the grid and the photovoltaic side for energy storage while also replenishing power to the grid and the load; the priority of power supply to the load is photovoltaic side >> energy storage cabinet >> grid. At night, the photovoltaic side stops supplying power, and the energy storage cabinet receives power from the grid for energy storage while also replenishing power to the grid and the load; the priority of power supply to the load is energy storage cabinet >> grid.

[0039] Off-grid mode: This mode automatically switches when grid power is interrupted. During the day, the photovoltaic (PV) system supplies power to the energy storage cabinet and the load, and the energy storage cabinet also replenishes power to the grid. The energy storage cabinet receives power from the PV system for energy storage while simultaneously replenishing power to the grid and the load. The priority for power supply to the load is: PV system >> energy storage cabinet. At night, when PV power supply stops, the energy storage cabinet uses its own stored energy to replenish power to the grid and the load.

[0040] 1) "Automatic Mode": In automatic mode, STS will default to grid-connected status regardless of whether the mains power, energy storage cabinet or photovoltaic side is powered on.

[0041] 2) "Grid-connected to off-grid switch": When the grid is abnormal or the STS detects that the grid amplitude and frequency are not within the allowable operating range, the STS sends a grid-connected to off-grid switch signal (high level). At the same time, the STS disconnects and the system switches to off-grid state. After receiving the grid-connected to off-grid switch signal, the energy storage cabinet must immediately and automatically switch to off-grid operation and give a response signal (high level is active) to ensure that the STS is in off-grid state.

[0042] 3) "Off-grid to grid-connected": When the amplitude and frequency on the grid side are within the allowable switching range, the STS first sends an off-grid to grid-connected IO signal (low level). When the STS receives the response signal from the energy storage cabinet (low level is active), the STS engages, connects to the grid, and automatically switches from off-grid to grid-connected operation.

[0043] The system can dynamically adjust the power source based on actual electricity demand, weather conditions, or electricity price fluctuations, thereby improving the product's redundancy and scalability.

[0044] In terms of safety, the system is equipped with a triple protection mechanism: miniature circuit breaker (overcurrent) + molded case circuit breaker (short circuit) + STS protection (built-in overvoltage / undervoltage, overfrequency / underfrequency protection); it can cut off the circuit in time when the equipment fails or is overloaded, protecting the equipment and personnel safety.

[0045] Meanwhile, the redundant design of the energy storage cabinet and photovoltaic inverter improves system reliability, ensuring that the system can still operate normally in the event of a single device failure. Multi-mode switching and redundancy design ensure that the product can adapt to complex power grid environments and extreme scenario requirements.

[0046] The specific embodiments described herein are merely illustrative examples illustrating the spirit of the invention. The above embodiments only express several implementation methods of this application, and their descriptions are relatively specific and detailed, but they should not be construed as limiting the scope of protection of this application. It should be noted that those skilled in the art to which this application pertains can make various modifications or additions to the described specific embodiments or use similar methods to replace them, but without departing from the spirit of this application or exceeding the scope defined by the appended claims. For those skilled in the art, multiple variations and improvements can be made without departing from the concept of this application. Therefore, the scope of protection of this application should be determined by the appended claims.

Claims

1. A 120kW automatic grid-connected / off-grid switching cabinet photovoltaic-storage system, characterized in that, It includes a grid-side circuit, which includes a static transfer switch (14), and the output terminals of the static transfer switch (14) are respectively connected to the equipment branch, the energy storage system circuit and the photovoltaic-storage system circuit.

2. The 120kW automatic grid-connected / off-grid switching cabinet photovoltaic-storage system according to claim 1, characterized in that, The grid-side circuit includes a grid-side AC circuit breaker (17), the incoming terminal of which is connected to the power supply terminal, the outgoing terminal of which is connected to the incoming terminal of the first current transformer (8) and the grid-side energy meter (1), respectively, and the outgoing terminal of the first current transformer (8) is connected to the incoming terminal of the static transfer switch (14).

3. A 120kW automatic grid-connected / off-grid switching cabinet photovoltaic-storage system according to claim 1, characterized in that, The equipment branch includes a second current transformer (15) and a load-side energy meter. The input terminal of the second current transformer (15) is connected to the output terminal of the static transfer switch (14). The output terminal of the second current transformer (15) is connected to the client equipment circuit and other equipment circuits respectively.

4. A 120kW automatic grid-connected / off-grid switching cabinet photovoltaic-storage system according to claim 3, characterized in that, The client equipment circuit includes a backup AC circuit breaker (16), the incoming terminal of the backup AC circuit breaker (16) is connected to the outgoing terminal of the static transfer switch (14), and the outgoing terminal of the backup AC circuit breaker (16) is connected to the client equipment in need.

5. A 120kW automatic grid-connected / off-grid switching cabinet photovoltaic-storage system according to claim 3, characterized in that, The other equipment circuits include a first AC miniature circuit breaker (11), a second AC miniature circuit breaker (12), and a third AC miniature circuit breaker (13). The input terminals of the first AC miniature circuit breaker (11), the second AC miniature circuit breaker (12), and the third AC miniature circuit breaker (13) are connected to the output terminals of a static transfer switch (14), and the output terminals are respectively connected to other equipment including a cooling fan and a temperature sensor.

6. A 120kW automatic grid-connected / off-grid switching cabinet photovoltaic-storage system according to claim 1, characterized in that, The energy storage system circuit includes an energy storage AC circuit breaker (10), the incoming terminal of the energy storage AC circuit breaker (10) is connected to the outgoing terminal of the static transfer switch (14), and the outgoing terminal of the energy storage AC circuit breaker (10) is connected to the air-cooled system energy storage cabinet.

7. A 120kW automatic grid-connected / off-grid switching cabinet photovoltaic-storage system according to claim 1, characterized in that, The photovoltaic energy storage system circuit includes a photovoltaic AC circuit breaker (9). The input terminal of the photovoltaic AC circuit breaker (9) is connected to the output terminal of the static transfer switch (14). The output terminal of the photovoltaic AC circuit breaker (9) is connected to the photovoltaic system composed of a photovoltaic inverter and photovoltaic modules.

8. A 120kW automatic grid-connected / off-grid switching cabinet photovoltaic-storage system according to claim 1, characterized in that, It also includes power-on alarm indicator lights, operation alarm indicator lights, and emergency stop buttons installed on the grid-connected / off-grid switching cabinet.

9. A 120kW automatic grid-connected / off-grid switching cabinet photovoltaic-storage system according to claim 1, characterized in that, It also includes a first grounding point and a second grounding point respectively set on the front and rear sides of the grid-connected switching cabinet.

10. A 120kW automatic grid-connected / off-grid switching cabinet photovoltaic-storage system according to claim 1, characterized in that, The air-cooled system circuit includes a first cooling fan and a second cooling fan installed on the inner wall of the grid-connected / off-grid switching cabinet.

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