Distributed photovoltaic power generation system

Abstract

The utility model provides a distributed photovoltaic power generation system, and relates to the technical field of power generation and distribution. Comprising a photovoltaic area, a grid-connected power distribution unit, a voltage conversion module and a power distribution module, and the power distribution module comprises a load direct supply unit and a power grid access unit; the output side of the photovoltaic area is connected with the input side of the grid-connected power distribution unit, the output side of the grid-connected power distribution unit is connected with the low-voltage input side of the voltage conversion module, the low-voltage output side of the voltage conversion module is connected with the load direct supply unit, and the high-voltage output side of the voltage conversion module is connected with the power grid access unit. According to the utility model, different power supply outputs can be adapted through multi-voltage-level power distribution, and the problem of limitation of the existing distributed photovoltaic power generation system in actual use is solved.

Description

Technical Field

[0001] This utility model relates to the field of power generation and distribution technology, specifically a distributed photovoltaic power generation system. Background Technology

[0002] In recent years, with the promotion of clean energy, photovoltaic (PV) power generation systems have been widely used in industrial, commercial, and residential sectors due to their advantages such as reducing energy loss and carbon emissions. Specifically, a PV power generation system refers to a system that uses solar energy to generate electricity; its core is the direct conversion of solar energy into electrical energy through photovoltaic modules (i.e., solar panels). Traditional and commonly used PV power generation systems are typically centralized PV power plants, which have played an important role in energy transition. However, with technological advancements, the technical limitations and application restrictions of centralized PV power plants have become increasingly apparent, such as difficulty in adapting to dispersed user needs, significant line losses during long-distance transmission, and high operation and maintenance costs. Therefore, distributed PV power generation systems are becoming a key area of ​​market development.

[0003] Distributed photovoltaic (PV) power generation systems are a form of PV power generation developed and consumed locally. Their core characteristic is construction at or near the user's site, with the generated electricity primarily meeting the user's own needs, and surplus electricity fed into the grid. However, existing distributed PV power generation systems also have some limitations in practical applications. Specifically: existing distributed PV power generation systems typically use a single voltage level for power distribution, making it difficult to directly meet the differentiated needs of grid connection and local loads. This necessitates the use of multiple additional devices, leading to lower operating efficiency and less precise control over the balance between self-consumption and grid connection of surplus electricity. Furthermore, existing distributed PV power generation systems are prone to unreasonable layout of PV modules and inverters in the PV area, which can limit power generation efficiency and increase the failure rate.

[0004] In summary, this utility model provides a novel distributed photovoltaic power generation system. By optimizing the system architecture and improving the voltage conversion and power distribution modules, the overall performance of the distributed photovoltaic power generation system can be effectively enhanced. Utility Model Content

[0005] The purpose of this utility model is to provide a novel distributed photovoltaic power generation system to solve the limitations of existing distributed photovoltaic power generation systems in practical use, as mentioned in the background art.

[0006] This utility model is achieved using the following technical solution:

[0007] A distributed photovoltaic power generation system includes a photovoltaic area, a grid-connected distribution unit, a voltage conversion module, and a distribution module. The distribution module includes a load direct supply unit and a grid access unit. The output side of the photovoltaic area is connected to the input side of the grid-connected distribution unit, the output side of the grid-connected distribution unit is connected to the low-voltage input side of the voltage conversion module, the low-voltage output side of the voltage conversion module is connected to the load direct supply unit, and the high-voltage output side of the voltage conversion module is connected to the grid access unit.

[0008] In the distributed photovoltaic power generation system provided by this utility model, the photovoltaic zone is used to convert light energy into electrical energy, the grid-connected distribution unit is used to collect the electrical energy of the photovoltaic zone and distribute it to the voltage conversion module, the voltage conversion module is used to convert the voltage level of the electrical energy of the grid-connected distribution unit, and the load direct supply unit and the grid access unit in the distribution module are used for local load power supply and high-voltage grid access, respectively.

[0009] Furthermore, the photovoltaic zone includes several photovoltaic modules, which are connected to multiple inverters, and the multiple inverters are all connected to a grid-connected cabinet.

[0010] Furthermore, the grid-connected power distribution unit is a 0.4kV low-voltage side unit, and a grid connection point is provided in the 0.4kV low-voltage side unit, which corresponds to the grid-connected cabinet.

[0011] Furthermore, the voltage conversion module includes a transformer, wherein the high-voltage side winding of the transformer is connected in a delta configuration and the low-voltage side winding is connected in a star configuration.

[0012] Furthermore, the load direct supply unit is a 0.66-0.8kV low-voltage side unit, and a switching element is provided in the 0.66-0.8kV low-voltage side unit, which is connected to the MF device or the EAF device.

[0013] Furthermore, the power grid access unit is a 10kV high-voltage side unit, which is equipped with several high-voltage distribution cabinets, and these cabinets are connected to the 10kV power grid.

[0014] Furthermore, the photovoltaic modules are divided into two groups, and the inverters connected to the photovoltaic modules are also divided into two groups. Each group of inverters is connected to a grid-connected cabinet, and the two grid-connected cabinets are respectively connected to two grid-connected points in the 0.4kV low-voltage side unit.

[0015] Furthermore, both grid connection points are connected to the outgoing line cabinet, and one of the grid connection points is also connected to the capacitor bank and the incoming line cabinet in sequence. The output side of the incoming line cabinet is connected to the low-voltage input side of the voltage conversion module.

[0016] Furthermore, an overcurrent protection device is provided between the inverter and the photovoltaic module, which is a fuse or a circuit breaker.

[0017] Furthermore, the high-voltage distribution cabinet is equipped with a relay protection device, which includes an overvoltage protection unit, an undervoltage protection unit, and a short-circuit protection unit.

[0018] The beneficial effects achieved by this utility model are:

[0019] This invention provides a distributed photovoltaic power generation system. By setting up an energy path of "photovoltaic area → grid-connected distribution unit → voltage conversion module → load direct supply unit / grid access unit", the process of energy collection, conversion and distribution can be clearly defined. Based on this, compared with the limitations of traditional photovoltaic power generation systems, this invention can adapt to different power outputs through multi-voltage level distribution, achieving good self-consumption and surplus power grid connection effects. Attached Figure Description

[0020] Figure 1 This is a schematic diagram of the distributed photovoltaic power generation system described in an embodiment of this utility model.

[0021] In the diagram: 1. Photovoltaic area; 2. Grid-connected power distribution unit; 3. Voltage conversion module; 4. Load direct supply unit; 5. Grid access unit. Detailed Implementation

[0022] The technical solutions of the present invention will be clearly and completely described below with reference to the accompanying drawings of the embodiments of the present invention.

[0023] Example 1

[0024] This embodiment provides a distributed photovoltaic power generation system, such as Figure 1 As shown:

[0025] The system includes a photovoltaic zone 1, a grid-connected power distribution unit 2, a voltage conversion module 3, and a power distribution module. The power distribution module includes a load direct supply unit 4 and a grid access unit 5. In this structure, the photovoltaic zone 1 converts solar energy into electrical energy. The grid-connected power distribution unit 2 collects the electrical energy from the photovoltaic zone 1 and distributes it to the voltage conversion module 3. The voltage conversion module 3 converts the voltage level of the electrical energy from the grid-connected power distribution unit 2. The load direct supply unit 4 and the grid access unit 5 in the power distribution module are used for local load power supply and high-voltage grid access, respectively.

[0026] Specifically, in this embodiment:

[0027] Photovoltaic zone 1 includes 7 photovoltaic modules (PV1-PV7), 7 inverters (NB1-NB7), and 2 grid-connected cabinets (AM1, AM2). Each photovoltaic module contains several photovoltaic solar panels, and the 7 photovoltaic modules are connected to the corresponding 7 inverters. The 7 inverters have different power parameters, including 30kW and 40kW for small-scale photovoltaic modules and 100kW and 150kW for large-scale photovoltaic modules. The 7 photovoltaic modules are divided into two groups (PV1-PV3, PV4-PV7), and the 7 inverters are also divided into two groups (NB1-NB3, NB4-NB7), with each group of inverters connected to one grid-connected cabinet. In this structure, the use of inverters with different power ratings can accommodate photovoltaic modules of different sizes, thereby maximizing the utilization of solar resources and improving solar energy conversion efficiency. The partitioned photovoltaic modules facilitate maintenance and repair, and reduce the impact of a failure in one area on the entire photovoltaic system, thus improving system reliability.

[0028] Grid-connected distribution unit 2 is a 0.4kV low-voltage side unit, which has two grid connection points (PCO1 and PCO2), each corresponding to one of the two grid-connected cabinets. Both grid connection points are connected to the outgoing cabinet OC. Grid connection point PCO2 is also connected to the capacitor bank ACP and the incoming cabinet IC in sequence. The output side of the incoming cabinet IC is connected to the low-voltage input side of the voltage conversion module 3. In this structure, the two grid connection points are used to collect power from the photovoltaic area. The grid connection points are connected to the outgoing cabinet OC to achieve power distribution. The capacitor bank ACP is used for reactive power compensation, and the incoming cabinet IC is used for power distribution and circuit protection.

[0029] The voltage conversion module 3 includes a transformer T. The high-voltage winding of transformer T is connected in a delta configuration, and the low-voltage winding is connected in a star configuration. Transformer T is a model S13~500kVA with a voltage rating of 10±2×2.5% / 0.66 / 0.4kV, an impedance voltage of 6.5%, a connection group of Dyn11, and a capacity ratio of 500 / 500 / 400. In this structure, transformer T is the core conversion device. Through the delta connection of the high-voltage winding and the star connection of the low-voltage winding, it ensures phase matching between the high and low voltage sides, enabling it to receive 0.4kV low-voltage photovoltaic power and convert it into two outputs to meet the dual voltage requirements of grid connection and local loads.

[0030] Load direct supply unit 4 is a 0.66–0.8kV low-voltage side unit. This unit is equipped with switching elements that can be selectively connected to MF equipment (such as motors) or EAF equipment (such as electric arc furnaces). Based on this, it can directly supply power to the plant load, achieving self-generation and self-consumption.

[0031] Grid access unit 5 is a 10kV high-voltage side unit, which is equipped with three high-voltage distribution cabinets (AA1~AA2), all of which are connected to the 10kV power grid. Based on this, surplus electricity can be fed into the grid.

[0032] Additionally, depending on the actual situation, an overcurrent protection device, such as a fuse or circuit breaker, can be installed between the inverter and the photovoltaic modules. A relay protection device, including overvoltage protection, undervoltage protection, and short-circuit protection units, can be installed in the high-voltage distribution cabinet. In this structure, the overcurrent protection device can monitor the current in real time and cut off the circuit when the photovoltaic module circuit current is abnormal; the relay protection device is used to monitor the voltage and current on the grid side and activate protection when an abnormality occurs.

[0033] Based on the above structure, the distributed photovoltaic power generation system described in this embodiment operates as follows: First, the photovoltaic modules in photovoltaic zone 1 absorb light energy to generate direct current (DC). This DC is converted into alternating current (AC) by an inverter. The converted AC is then fed to two grid-connected cabinets and enters the grid-connected distribution unit 2 through the grid connection point. Then, the grid-connected distribution unit 2 transmits 0.4kV power to the voltage conversion module 3. The transformer T in the voltage conversion module 3 outputs 0.66–0.8kV low-voltage power to the load direct supply unit 4, which, through switching elements, connects to either MF equipment (such as the motor driving a wind turbine) or EAF equipment (such as an electric arc furnace) to directly supply power to the plant load. Alternatively, it can step up the 0.4kV power to 10kV and connect it to the 10kV grid through the high-voltage side grid access module.

[0034] It should be noted that the parts of the above solution that are not described in detail or in detail are all prior art, and are not improvements made by this utility model to the prior art, nor are they within the protection scope of the technical solution of this utility model. Therefore, they will not be elaborated on in this article.

[0035] Of course, the above description is only a preferred embodiment of this utility model and should not be considered as limiting the scope of the embodiments of this utility model. This utility model is not limited to the above examples, and all equivalent changes and improvements made by those skilled in the art within the scope of this utility model should be included in the patent coverage of this utility model.

Claims

1. A distributed photovoltaic power generation system, characterized in that: It includes a photovoltaic zone (1), a grid-connected power distribution unit (2), a voltage conversion module (3), and a power distribution module. The power distribution module includes a load direct supply unit (4) and a grid access unit (5). The output side of the photovoltaic zone (1) is connected to the input side of the grid-connected power distribution unit (2), the output side of the grid-connected power distribution unit (2) is connected to the low-voltage input side of the voltage conversion module (3), the low-voltage output side of the voltage conversion module (3) is connected to the load direct supply unit (4), and the high-voltage output side of the voltage conversion module (3) is connected to the grid access unit (5).

2. The distributed photovoltaic power generation system according to claim 1, characterized in that: The photovoltaic area (1) includes several photovoltaic modules, which are connected to multiple inverters, and the multiple inverters are all connected to the grid-connected cabinet.

3. The distributed photovoltaic power generation system according to claim 2, characterized in that: The grid-connected power distribution unit (2) is a 0.4kV low-voltage side unit. The 0.4kV low-voltage side unit is equipped with a grid connection point, which corresponds to the grid-connected cabinet.

4. The distributed photovoltaic power system of claim 1, wherein: The voltage conversion module (3) includes a transformer, wherein the high-voltage side winding of the transformer is connected in a delta configuration and the low-voltage side winding is connected in a star configuration.

5. The distributed photovoltaic power system of claim 1, wherein: The load direct supply unit (4) is a 0.66-0.8kV low-voltage side unit. The 0.66-0.8kV low-voltage side unit is equipped with a switching element, which is connected to the MF device or the EAF device.

6. The distributed photovoltaic power system of claim 1, wherein: The grid access unit (5) is a 10kV high-voltage side unit. The 10kV high-voltage side unit is equipped with several high-voltage distribution cabinets, which are connected to the 10kV power grid.

7. The distributed photovoltaic power system of claim 3, wherein: The photovoltaic modules are divided into two groups, and the inverters connected to the photovoltaic modules are also divided into two groups. Each group of inverters is connected to a grid-connected cabinet, and the two grid-connected cabinets are respectively connected to two grid-connected points in the 0.4kV low-voltage side unit.

8. The distributed photovoltaic power system of claim 7, wherein: Both grid connection points are connected to the outgoing line cabinet, and one of the grid connection points is also connected to the capacitor cabinet and the incoming line cabinet in sequence. The output side of the incoming line cabinet is connected to the low-voltage input side of the voltage conversion module (3).

9. The distributed photovoltaic power system of claim 2, wherein: An overcurrent protection device, which is a fuse or circuit breaker, is provided between the inverter and the photovoltaic module.

10. The distributed photovoltaic power system of claim 6, wherein: The high-voltage distribution cabinet is equipped with a relay protection device, which includes an overvoltage protection unit, an undervoltage protection unit, and a short-circuit protection unit.

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