Photovoltaic energy storage system, grounding method and wiring device

Abstract

The invention relates to a photovoltaic energy storage system, in particular to a photovoltaic energy storage system, a grounding method and a wiring device. The photovoltaic energy storage system comprises a power distribution cabinet, photovoltaic equipment, energy storage equipment and an energy storage converter, the power distribution cabinet, the photovoltaic equipment, the energy storage equipment and the energy storage converter are grounded through ground wires respectively, each ground wire is connected with angle iron and then buried underground, and the angle iron is connected in series through a connecting line to form an annular connecting line. And the power distribution cabinet, the photovoltaic equipment, the energy storage equipment and the energy storage converter are surrounded by the annular connecting line. The anti-interference capability of a large-scale energy storage system, especially a system with more than 1MW, can be well optimized, and can be used as the grounding of a megawatt-level energy storage power station, so that the interference problem of the large-scale energy storage system is solved, all the grounds are connected together through connecting wires, the unification of reference zero potential of the whole energy storage system is ensured, and the reliability of the whole energy storage system is improved. And external strong interference is shielded through the looped network, so that the whole system is isolated to a certain extent.

Description

Technical Field

[0001] This invention relates to a photovoltaic energy storage system, and more particularly to a photovoltaic energy storage system, a grounding method, and a wiring device. Background Technology

[0002] To ensure the safe operation of photovoltaic (PV) energy storage systems, existing systems typically use a distribution cabinet for grounding. The distribution cabinet grounding unit connects the ground wires of all system components to a unified distribution cabinet grounding copper busbar via series and / or parallel connections. This busbar then extends to angle iron buried deep underground, forming the grounding for the entire system. This grounding method has limitations on system size and deployment environment. For larger systems or systems deployed in complex electromagnetic environments, it cannot achieve adequate grounding. Various interferences form circulating currents on the ground wires, continuously interfering with all components of the system. Over time, a large amount of interference accumulates in the grounding system, filling the entire system's communication with noise. In severe cases, this can cause communication failure, rendering the entire system unable to operate normally. Summary of the Invention

[0003] To address the aforementioned problems, in a first aspect, embodiments of this application provide a photovoltaic energy storage system, the system comprising: The system includes a power distribution cabinet, photovoltaic equipment, energy storage equipment, and energy storage converter. Each of the power distribution cabinet, photovoltaic equipment, energy storage equipment, and energy storage converter is grounded through a ground wire. Each ground wire is connected to an angle iron and buried underground. The angle irons are connected in series by connecting wires to form a ring connection line. The ring connection line surrounds the power distribution cabinet, photovoltaic equipment, energy storage equipment, and energy storage converter within its ring.

[0004] The above method effectively optimizes the anti-interference capability of large-scale energy storage systems, especially those above 1MW. It can be used as the grounding for megawatt-level energy storage power stations, solving the interference problem of large-scale energy storage systems. Furthermore, by connecting all grounds together through connecting lines, it ensures the uniformity of the reference zero potential of the entire energy storage system and shields against strong external interference through the ring network, thus providing a certain degree of isolation for the entire system.

[0005] In one possible implementation, the connecting line is provided with a plurality of stripped wire segments, which are distributed at intervals on the connecting line.

[0006] In one possible implementation, the photovoltaic equipment and energy storage equipment are arranged at 180 degrees in the equipment cluster, so that they have the farthest equipment distance in the equipment cluster.

[0007] In one possible implementation, the distribution cabinet further includes a power grid and load distribution module and a low-voltage control module, wherein the power grid and load distribution module and the low-voltage control module are connected to the same ground wire and angle iron.

[0008] In one possible implementation, the length of the ground wire is greater than or equal to 30m.

[0009] In one possible implementation, the connecting wire is a single-core wire with a diameter of 1 square millimeter.

[0010] Secondly, embodiments of this application also provide a grounding method for grounding the photovoltaic energy storage device of the first aspect, the method comprising the steps of: The distribution cabinets, photovoltaic equipment, energy storage equipment and energy storage converters are arranged into equipment clusters; Each of the power distribution cabinet, photovoltaic equipment, energy storage equipment, and energy storage converter is individually connected to a ground wire. The grounding wires are buried underground using angle irons; Angle irons are connected in series by connecting wires to form a closed loop connection line, which surrounds the equipment cluster.

[0011] Thirdly, embodiments of this application also provide a wiring device for grounding a photovoltaic energy storage device according to the first aspect, the device comprising: Multiple ground wires are connected to the power distribution cabinet, photovoltaic equipment, energy storage equipment and energy storage converter respectively; Multiple angle irons, each angle iron connected to a ground wire; A connecting line is used to connect the multiple angle irons in series to form a closed loop connecting line, which surrounds the equipment cluster. Attached Figure Description

[0012] Figure 1 This is a schematic diagram of the modular structure of the photovoltaic energy storage system in the first embodiment; Figure 2 The CAN bus communication test waveform of the photovoltaic energy storage system when the distribution cabinet is uniformly grounded; Figure 3 The waveforms for CAN bus communication of the photovoltaic energy storage system in the first embodiment are shown. Figure 4 A flowchart of the second embodiment of the present invention. Detailed Implementation

[0013] The following detailed description, in conjunction with specific embodiments and accompanying drawings, clarifies that the described embodiments are only a portion, not all, of the embodiments. All other embodiments obtained by those skilled in the art based on the following embodiments without inventive effort are also within the scope of protection of this invention.

[0014] It should be understood that if the controllers or control circuits involved in the embodiments are conventional control technologies or units for those skilled in the art, such as the control circuits of the controllers, they can be implemented by those skilled in the art using existing technologies.

[0015] The disclosure of the embodiments provides many different implementations or examples for different ways of implementing the present invention. To simplify the disclosure of the present invention, the embodiments describe components and arrangements of specific examples. Of course, these are merely examples and are not intended to limit the present invention. Furthermore, reference numerals and / or reference letters may be repeated in different examples in the embodiments; such repetition is for simplification and clarity and does not in itself indicate a relationship between the various implementations and / or arrangements discussed. Moreover, if examples of various specific processes and materials are provided in the embodiments, those skilled in the art will recognize the application of other processes and / or the use of other materials.

[0016] First, it should be noted that the photovoltaic energy storage system of the first embodiment of this application, such as Figure 1 As shown, the system includes: The system comprises a distribution cabinet 1, a photovoltaic device 2, an energy storage device 3, and an energy storage converter 4. The distribution cabinet 1 is connected to a first ground wire 5, the photovoltaic device 2 is connected to a second ground wire 6, the energy storage device 3 is connected to a third ground wire 7, and the energy storage converter 4 is connected to a fourth ground wire 8. The first ground wire 5 is connected to a first angle iron 9, the second ground wire 6 is connected to a second angle iron 10, the third ground wire is connected to a third angle iron 11, and the fourth ground wire is connected to a fourth angle iron 12. Each ground wire extends outwards from the periphery of its respective device, distributing the angle irons around the outer edges of each component of the photovoltaic energy storage system. The angle irons are then connected in series via connecting wires 13 to form a closed loop, with the connecting wires 13 surrounding the periphery of each component of the photovoltaic energy storage system. The ground wires, angle irons, and connecting wires are buried deep underground. Since the ground wires are connected to surface equipment, their connecting ends protrude above the ground and connect to the corresponding component.

[0017] Among them, the distribution cabinet 1 (AC / DC power distribution unit) is the central hub for power distribution, collection, and protection of the system. Its main functions include: power collection, concentrating power from multiple circuits; power distribution, distributing electrical energy to loads or transmitting it to the power grid; and protection, equipped with circuit breakers, fuses, surge protectors, and other components to quickly disconnect faulty circuits in the event of overload, short circuit, grounding, or lightning strikes, thus protecting equipment and personnel safety. In this embodiment, the distribution cabinet 1 mainly includes a power grid and load distribution module 101 and a low-voltage control module 102. The power grid and load distribution module 101 and the low-voltage control module 102 are connected to the first angle iron 9 via a common grounding method through the first ground wire 5.

[0018] Photovoltaic equipment 2 (photovoltaic module / array) is the energy input end of the system, and its core function is to directly convert the radiant energy of sunlight into direct current electrical energy. Photovoltaic modules (usually photovoltaic panels) generate electrical energy through the photoelectric effect.

[0019] Energy storage device 3 (battery module / system) mainly refers to the battery module and battery management system (BMS). Its main function is to store the excess electrical energy generated by photovoltaic equipment during peak power generation but not immediately used, as well as the electrical energy obtained from the grid during off-peak electricity prices. At the same time, it can release the stored electrical energy during peak electricity consumption periods, when photovoltaic power generation is not in progress, or when the grid experiences a power outage, to supply the load, thus realizing the time transfer of electrical energy and stable power supply.

[0020] The Power Storage Converter (PCS) is the energy conversion and control center of the system. It enables bidirectional flow and precise control of electrical energy: during charging, it converts AC power to DC power to charge the battery (rectification); during discharging, it converts the DC power from the battery to AC power to supply the load or transmit it to the grid (inversion). The PCS is also responsible for communicating with the battery management system and the energy management system to ensure the safe and efficient charging and discharging of the battery, and to provide active and reactive power support according to the needs of the grid or users.

[0021] It should be noted that since the connecting lines are buried deep underground, while the various components of the photovoltaic energy storage equipment are generally located on the ground or on ground appendages, the aforementioned connecting lines 13 surrounding the periphery of the various components of the photovoltaic energy storage system indicates that the connecting lines are deployed within the projection range of the various equipment components on the ground.

[0022] After the above grounding connection, the anti-interference capability of large-scale energy storage systems, especially those above 1MW, is well optimized. It can be used as the grounding for megawatt-level energy storage power stations. It not only solves the interference problem of large-scale energy storage systems, but also connects all the grounds together through the connecting line. This ensures the uniformity of the reference zero potential of the entire energy storage system, and shields strong external interference through the ring network, thus providing a certain degree of isolation for the entire system.

[0023] like Figure 2 and Figure 3 As shown, Figure 2 The waveforms are from a CAN bus communication test of a photovoltaic energy storage system under existing grounding methods. It can be seen that the CAN bus has significant interference when using traditional grounding schemes in photovoltaic energy storage systems. 1.2V is the point for determining high and low levels. A value above 1.2V is considered high, and a value below 1.2V is considered low. It is evident that the existing grounding method has a large amount of noise interference. Some high levels will be identified as low levels, and some low levels will be identified as high levels, making it impossible for the transceiver to accurately identify the information. Figure 3 This is the CAN bus communication test waveform of the photovoltaic energy storage system in the first embodiment, provided by... Figure 3As can be seen, the communication waveform becomes stable, with almost no fluctuations.

[0024] In this embodiment, since each component of the entire system is grounded separately, the reference zero potential of each component is not uniform, which has a certain impact on system control. Therefore, after connecting them with connecting lines, each component of the entire photovoltaic energy storage system can have a uniform reference zero potential.

[0025] Because multiple components in the system can potentially interfere with each other via a common ground path, current always chooses the path of lowest impedance to return to the source. If the return paths of various components overlap on a ground plane, their return currents will cross-interfere. This type of interference is generally ground loop noise and high-frequency noise coupling. To further manage the current return path, thereby eliminating common impedance coupling and preventing noise crosstalk, in this embodiment, the connecting line is provided with multiple stripped wire segments, which are spaced apart. This operation is mainly to prevent interference from forming a circulating current through the connecting line. The spacing between the stripped wire segments can be 3-5m, and the exposed wire of each stripped segment is about 5cm. After stripping, the wire is buried underground according to the above steps to form a segmented grounding.

[0026] Because photovoltaic inverters and energy storage converters (PCS) are high-frequency, high-power interference sources among the various components of photovoltaic energy storage equipment, even after being individually grounded, there will still be a certain degree of earth coupling. If the distance between the two grounding electrodes is not far enough, especially under high-frequency interference, potential difference coupling will still exist between them due to the conductivity of the earth itself. High-frequency interference current can still be induced through the earth to the grounding grid of another device, thus causing electromagnetic compatibility problems at the system level. Therefore, photovoltaic equipment and energy storage equipment generate the most external interference. Therefore, in this embodiment, the photovoltaic equipment and energy storage equipment are arranged at 180 degrees in the equipment cluster, so that they have the farthest equipment distance in the cluster.

[0027] In the power distribution cabinet, the power distribution cabinet further includes a power grid and load distribution module and a low-voltage control module, the power grid and load distribution module and the low-voltage control module are connected to the same ground wire and angle iron.

[0028] In other specific aspects of implementation, in this embodiment, the length of the ground wire is greater than or equal to 30m, and the connecting wire is a single-core wire with a diameter of 1 square millimeter.

[0029] In the first embodiment, the technical solution of separately grounding the distribution cabinet 1, photovoltaic equipment 2, energy storage equipment 3, and energy storage converter 4 is used as an example to illustrate the connection of angle irons into a loop. In actual implementation, the photovoltaic energy storage system is not limited to the above-mentioned component modules. The concept of the above embodiment can be used to add equipment. At the same time, each component device is not limited to a single device. For example, photovoltaic equipment 2 can be composed of multiple photovoltaic panels, and energy storage equipment can also include multiple energy storage boxes. For the multiple individual components inside each component device, they can be grounded separately according to the above grounding method, or they can be grounded uniformly and then grounded according to the above method.

[0030] The second embodiment also provides a grounding method for implementing the grounding of the photovoltaic energy storage device in the first embodiment, the method comprising the following steps: S1. Arrange the power distribution cabinet, photovoltaic equipment, energy storage equipment and energy storage converter into an equipment cluster; S2. Connect the power distribution cabinet, photovoltaic equipment, energy storage equipment and energy storage converter to the ground wire individually; S3. Bury the grounding wires underground using angle irons; S4. Angle irons are connected in series by connecting wires to form a closed loop connection line, which surrounds the equipment cluster.

[0031] After the above steps, the photovoltaic energy storage device in the first embodiment can be grounded, and the aforementioned technical effects can be achieved, which will not be repeated here.

[0032] The third embodiment provides a wiring device for grounding a photovoltaic energy storage device in the first aspect, the device comprising: Multiple ground wires, each ground wire being connected to the power distribution cabinet, photovoltaic equipment, energy storage equipment, and energy storage converter respectively; Multiple angle irons, each angle iron connected to a ground wire; A connecting line is used to connect the multiple angle irons in series to form a closed loop connecting line, which surrounds the equipment cluster.

[0033] The composition of the grounding device can be referred to in the first embodiment and Figure 1 As shown, the wiring device in this embodiment is obtained by removing the various components of the photovoltaic energy storage device. Its working principle is also described in detail in the first embodiment.

[0034] The above description is merely a preferred embodiment of the present application and does not limit the scope of disclosure of the embodiments of the present application. Any equivalent structural or procedural transformations made using the description and drawings of the embodiments of the present application, or direct or indirect applications in other related technical fields, are similarly included within the scope of patent protection supported by the embodiments of the present application.

Claims

1. A photovoltaic energy storage system, characterized in that, include: The system includes a power distribution cabinet, photovoltaic equipment, energy storage equipment, and energy storage converter. Each of the power distribution cabinet, photovoltaic equipment, energy storage equipment, and energy storage converter is grounded through a ground wire. Each ground wire is connected to an angle iron and buried underground. The angle irons are connected in series by connecting wires to form a ring connection line. The ring connection line surrounds the power distribution cabinet, photovoltaic equipment, energy storage equipment, and energy storage converter within its ring.

2. The photovoltaic energy storage system as described in claim 1, characterized in that, The connecting line is provided with multiple stripped wire segments, which are distributed at intervals on the connecting line.

3. The photovoltaic energy storage system as described in claim 1, characterized in that, The photovoltaic equipment and energy storage equipment are arranged at a 180-degree angle in the equipment cluster, making them the furthest apart in the cluster.

4. The photovoltaic energy storage system as described in claim 1, characterized in that, The distribution cabinet further includes a power grid and load distribution module and a low-voltage control module, wherein the power grid and load distribution module and the low-voltage control module are connected to the same ground wire and angle iron.

5. The photovoltaic energy storage system as described in claim 1, characterized in that, The length of the ground wire is greater than or equal to 30m.

6. The photovoltaic energy storage system as described in claim 1, characterized in that, The connecting wire is a single-core wire with a diameter of 1 square millimeter.

7. The grounding method for a photovoltaic energy storage system as described in any one of claims 1-6, the method comprising the steps of: The distribution cabinets, photovoltaic equipment, energy storage equipment and energy storage converters are arranged into equipment clusters; Each of the power distribution cabinet, photovoltaic equipment, energy storage equipment, and energy storage converter is individually connected to a ground wire. The grounding wires are buried underground using angle irons; Angle irons are connected in series by connecting wires to form a closed loop connection line, which surrounds the equipment cluster.

8. The wiring device for a photovoltaic energy storage system as described in any one of claims 1-6, the device comprising: Multiple ground wires are connected to the power distribution cabinet, photovoltaic equipment, energy storage equipment and energy storage converter respectively; Multiple angle irons, each angle iron connected to a ground wire; A connecting line is used to connect the multiple angle irons in series to form a closed loop connecting line, which surrounds the equipment cluster.

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