Distributed photovoltaic system and power grid system

Abstract

The invention discloses a distributed photovoltaic system and a power grid system, and relates to the technical field of photovoltaic power generation, the distributed photovoltaic system comprises a plurality of dispersedly arranged photovoltaic units, a confluence device, a boost grid-connected device and a secondary equipment prefabricated cabin, and each photovoltaic unit can convert solar energy into electric energy; the confluence device is connected with each photovoltaic unit through a wire, and the confluence device is used for collecting the electric energy generated by the plurality of dispersedly arranged photovoltaic units; the boosting grid-connected device is used for boosting low-voltage electric energy to high voltage and connecting the electric energy to a high-voltage power grid, the boosting grid-connected device comprises a primary equipment prefabricated cabin, and the convergence device is connected with the primary equipment prefabricated cabin; and the secondary equipment prefabricated cabin is electrically connected with the convergence device and the primary equipment prefabricated cabin. According to the technical scheme, the problem that in an existing rural distributed photovoltaic power station, the total installation amount is limited by the capacity of an existing transformer, and consequently a large number of photovoltaic panels cannot be continuously installed in the village can be solved.

Description

Technical Field

[0001] The present invention relates to the technical field of photovoltaic power generation, and in particular to a distributed photovoltaic system and a power grid system. Background Art

[0002] At present, in the distributed photovoltaic power stations in rural areas, household photovoltaic panels are mainly built on the roofs of rural houses. Because the installed capacity is generally small, the electricity generated by the photovoltaic panels passes through the inverter and the grid-connected box, and is generally connected to the main line near the building in a T-connection manner.

[0003] Although the T-connection grid-connected method is simple, the total amount that can be installed in the village is limited by the existing transformer capacity, which makes it impossible to install a large number of photovoltaic panels continuously in the village. Due to the lack of independent secondary equipment, scheduling and control are impossible, and the quality of the electricity generated by photovoltaic panels is generally low. After years of installation accumulation, it will have a huge impact on the carrying capacity of the local power grid. Summary of the Invention

[0004] The main purpose of this invention is to propose a distributed photovoltaic system and power grid system, which aims to solve the problem that the total installation amount of existing distributed photovoltaic power stations in rural areas is limited by the existing transformer capacity, resulting in the inability to install a large number of photovoltaic panels continuously in the village. At the same time, it provides grid-connected power quality and improves the dispatching and protection capabilities of the power station.

[0005] To achieve the above-mentioned purpose, the distributed photovoltaic system proposed in the present invention includes a plurality of dispersed photovoltaic units, a confluence device, a boosting and grid-connected device and a secondary equipment prefabricated cabin, each of the photovoltaic units can convert solar energy into electrical energy; the confluence device is connected to the wires of each photovoltaic unit, and the confluence device is used to collect the electrical energy generated by the plurality of dispersed photovoltaic units; the boosting and grid-connected device is used to boost low-voltage electrical energy to high voltage and connect the electrical energy to the high-voltage power grid, the boosting and grid-connected device includes a primary equipment prefabricated cabin, the confluence device is connected to the primary equipment prefabricated cabin; the secondary equipment prefabricated cabin is electrically connected to the confluence device and the primary equipment prefabricated cabin; wherein, the primary equipment prefabricated cabin is used for the transmission, distribution and control of electrical energy; the secondary equipment prefabricated cabin is used for the monitoring, protection, control and communication of electrical energy.

[0006] In one embodiment, an inverter is provided between each of the photovoltaic units and a junction device, the junction device includes a grid-connected cabinet and multiple first junction boxes, and a photovoltaic unit is connected to an inverter, a first junction box and the grid-connected cabinet in sequence, each of the first junction boxes is connected in series, and each of the inverters is connected in parallel.

[0007] In one embodiment, the combiner device includes a plurality of grid-connected cabinets, each of the grid-connected cabinets is connected in parallel, and each of the grid-connected cabinets is connected to a plurality of the first combiner boxes.

[0008] In one embodiment, the prefabricated primary equipment cabin has a second combiner box, and the second combiner box connects each of the power cabinets and the prefabricated primary equipment cabin.

[0009] In one embodiment, each of the first combiner boxes is provided with a first circuit breaker, and each of the second combiner boxes is provided with a second circuit breaker. Both the first circuit breakers and the second circuit breakers are electrically connected to the secondary equipment prefabricated cabin.

[0010] In one embodiment, the boost grid-connected device includes a low-voltage cabinet, a transformer, and a high-voltage cabinet. The low-voltage cabinet is connected in series with the transformer and the high-voltage cabinet in sequence. The low-voltage cabinet is connected to the merging device, and the electric energy collected by the merging device can be transmitted to the low-voltage cabinet.

[0011] In one embodiment, a metering device is further provided between the distributed photovoltaic system and the main line, and the metering device is used to measure the electric energy transmitted from the high-voltage cabinet to the main line.

[0012] In one embodiment, the prefabricated primary equipment cabin is provided with a reactive power compensation device, an incoming line cabinet, a station transformer cabinet, a PT cabinet, a metering cabinet, and an outgoing line cabinet.

[0013] In one embodiment, the secondary equipment prefabricated cabin is equipped with telecontrol communication, integrated protection screen, power grid dispatching host and automatic control host.

[0014] The present invention further proposes a power grid system, comprising a main line and at least two distributed photovoltaic systems, each of the distributed photovoltaic systems being connected to the main line, and each of the distributed photovoltaic systems being spaced apart from the main line.

[0015] The distributed photovoltaic system of the present invention realizes efficient conversion of solar energy through multiple dispersed photovoltaic units. Each photovoltaic unit is composed of several photovoltaic panels, which are installed on the roof of rural houses or other suitable locations, and transmit the generated low-voltage DC power to the convergence device through wires. The convergence device adopts a multi-channel input and one-channel output structure to collect the power of multiple photovoltaic units into one channel, and transmit it to the boost grid-connected device through the DC bus. The boost grid-connected device is composed of a primary equipment prefabricated cabin and a secondary equipment prefabricated cabin. The primary equipment prefabricated cabin contains transformers, circuit breakers and other equipment for boosting low-voltage DC power into high-voltage AC power to meet the access requirements of the high-voltage power grid; the secondary equipment prefabricated cabin is equipped with intelligent controllers, protection devices, communication modules, etc. to realize the monitoring, protection and communication functions of electric energy. The communication network of the secondary equipment prefabricated cabin is connected to the convergence device to collect system operation data in real time, and intelligently adjust the output power of the photovoltaic unit according to the grid load and photovoltaic output to optimize the system operation status. For example, when there is sufficient sunlight, the secondary equipment prefabricated cabin can instruct the photovoltaic unit to operate at full power and store excess electricity through the energy storage system; when there is insufficient sunlight or the grid load is peak, the stored energy is released to ensure stable output of the system. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the following briefly introduces the drawings required for use in the embodiments or the description of the prior art. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on the structures shown in these drawings without paying any creative work.

[0017] Figure 1 A schematic structural diagram of an embodiment of a distributed photovoltaic system provided by the present invention;

[0018] Figure 2 This is a structural schematic diagram of another embodiment of the distributed photovoltaic system provided by the present invention.

[0019] Description of Figure Numbers:

[0020] 100. Distributed photovoltaic system; 1. Photovoltaic unit; 2. Merging device; 3. Booster grid-connected device; 31. Primary equipment prefabricated cabin; 4. Secondary equipment prefabricated cabin; 21. Grid-connected cabinet; 22. Inverter; 23. First combiner box; 311. Second combiner box; 5. Metering device.

[0021] The purpose, features and advantages of the present invention will be further described with reference to the accompanying drawings and in conjunction with the embodiments. DETAILED DESCRIPTION

[0022] The following will clearly and completely describe the technical solutions in the embodiments of the present invention in conjunction with the accompanying drawings. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making any creative efforts shall fall within the scope of protection of the present invention.

[0023] It should be noted that if the embodiments of the present invention involve directional indications (such as up, down, left, right, front, back, etc.), the directional indications are only used to explain the relative position relationship, movement status, etc. between the components under a certain specific posture. If the specific posture changes, the directional indications will also change accordingly.

[0024] In addition, if there are descriptions involving "first", "second", etc. in the embodiments of the present invention, the descriptions of "first", "second", etc. are only for descriptive purposes and cannot be understood as indicating or suggesting their relative importance or implicitly indicating the number of the indicated technical features. Therefore, the features limited to "first" and "second" may explicitly or implicitly include at least one of such features. In addition, if "and / or" or "and / or" appears in the full text, its meaning includes three parallel solutions. Taking "A and / or B" as an example, it includes solution A, solution B, or solutions that satisfy both A and B. In addition, the technical solutions between the various embodiments can be combined with each other, but it must be based on the ability of ordinary technicians in this field to implement. When the combination of technical solutions is mutually contradictory or cannot be implemented, it should be deemed that such a combination of technical solutions does not exist and is not within the scope of protection required by the present invention.

[0025] See also Figure 1 and Figure 2 In one embodiment of the present invention, the distributed photovoltaic system 100 includes a plurality of dispersed photovoltaic units 1, a confluence device 2, a boost grid-connected device 3 and a secondary equipment prefabricated cabin 4, each of the photovoltaic units 1 can convert solar energy into electrical energy; the confluence device 2 is connected to each of the photovoltaic units 1 with a wire, and the confluence device 2 is used to collect the electrical energy generated by the plurality of dispersed photovoltaic units 1; the boost grid-connected device 3 is used to boost low-voltage electrical energy to high voltage and connect the electrical energy to the high-voltage power grid, the boost grid-connected device 3 includes a primary equipment prefabricated cabin 31, the confluence device 2 is connected to the primary equipment prefabricated cabin 31; the secondary equipment prefabricated cabin 4 is electrically connected to the confluence device 2 and the primary equipment prefabricated cabin 31; wherein, the primary equipment prefabricated cabin 31 is used for the transmission, distribution and control of electrical energy; the secondary equipment prefabricated cabin 4 is used for the monitoring, protection, control and communication of electrical energy.

[0026] In this embodiment, the distributed photovoltaic system 100 of the present invention achieves efficient operation through reasonable layout and modular design. Specifically, the distributed photovoltaic system 100 includes a plurality of dispersed photovoltaic units 1, a confluence device 2, a boost grid-connected device 3, and a secondary equipment prefabricated cabin 4. The plurality of photovoltaic units 1 are dispersedly arranged on the roof of a rural house or other suitable locations. Each photovoltaic unit 1 is composed of a number of photovoltaic panels and can independently convert solar energy into DC power. The DC power generated by the photovoltaic unit 1 is connected to the confluence device 2 through an inverter 22 or a direct wire. The confluence device 2 adopts a multi-input and one-way output structure to collect the power of the plurality of photovoltaic units 1 into one DC power. Subsequently, the DC power is transmitted to the primary equipment prefabricated cabin 31, and the built-in inverter 22 converts the DC power into low-voltage AC power, and then boosts the voltage to the voltage level required by the high-voltage power grid through a step-up transformer. The primary equipment prefabricated cabin 31 also integrates circuit breakers, disconnectors and other equipment for the transmission, distribution and control of electric energy. The secondary equipment prefabricated cabin 4 is connected to the junction box 2 and the primary equipment prefabricated cabin 31 via communication cables. A built-in monitoring system collects real-time power generation data from the photovoltaic cells 1 and grid operating parameters. Protection devices respond quickly to abnormal conditions based on pre-set logic. A control unit enables remote operation of the photovoltaic cells 1 and the booster equipment. The communication module transmits data to the secondary equipment prefabricated cabin 4, enabling centralized management and scheduling. For example, in a rural area, 100 houses are equipped with photovoltaic cells 1 on their roofs, each generating 5kW. After being combined by the junction box 2, the cells are connected to the 10kV high-voltage grid by the booster grid-connected device 3. The secondary equipment prefabricated cabin 4 monitors the power generation status of each cell in real time and performs scheduling. The integrated design of the junction box 2 and the booster grid-connected device 3 effectively addresses the transformer capacity limitations and low power quality issues associated with traditional T-connection. The modular design of the primary equipment prefabricated cabin 31 and the secondary equipment prefabricated cabin 4 enhances system flexibility and scalability, facilitating capacity expansion and upgrades based on actual needs. Secondly, the centralized monitoring and dispatching capabilities of the secondary equipment prefabricated cabin 4 enable observable, adjustable, and controllable distributed photovoltaic power plants, improving the grid's capacity and operational stability. For example, during peak load periods, the secondary equipment prefabricated cabin 4 can adjust the output power of the photovoltaic units 1 to optimize grid operation. In the event of a PV power plant failure, protective devices can quickly activate, isolating the faulty unit and ensuring grid safety. Furthermore, this system reduces the impact on the grid's carrying capacity, avoiding voltage fluctuations and harmonic pollution caused by the integration of a large number of distributed photovoltaic units, thereby improving the overall operational quality and reliability of the grid.

[0027] In one embodiment of the present invention, see Figure 2An inverter 22 is provided between each of the photovoltaic units 1 and the confluence device 2. The confluence device 2 includes a grid-connected cabinet 21 and multiple first confluence boxes 23. A photovoltaic unit 1 is connected to an inverter 22, a first confluence box 23 and the grid-connected cabinet 21 in sequence. The first confluence boxes 23 are connected in series, and the inverters 22 are connected in parallel.

[0028] In one embodiment, each photovoltaic unit 1 is connected to an independent inverter 22 via a wire. The inverter 22 converts the DC power generated by the photovoltaic unit 1 into AC power. Subsequently, the AC power is transmitted to the first combiner box 23 in the combiner device 2. The combiner device 2 is composed of multiple first combiner boxes 23 and a grid-connected cabinet 21. Each first combiner box 23 is connected in series to form an energy transmission path. The output end of the inverter 22 of each photovoltaic unit 1 is connected in parallel to the corresponding first combiner box 23. The power of multiple photovoltaic units 1 is gradually converged through the first combiner box 23 and finally converged to the grid-connected cabinet 21. The grid-connected cabinet 21 serves as the output end of the combiner device 2 and transmits the converged power to the boost grid-connected device 3 to complete the connection with the power grid. Each photovoltaic unit 1 is equipped with an independent inverter 22, which can flexibly adjust the output power according to the actual power generation situation of the photovoltaic unit 1, thereby improving the power generation efficiency and stability of the system. The parallel connection of inverters 22 ensures the independence of each photovoltaic unit 1. Even if a photovoltaic unit 1 or inverter 22 fails, it will not affect the normal operation of other units. The series connection of the first combiner box 23 enables the step-by-step aggregation of electrical energy, reducing line losses and improving energy transmission efficiency. The grid cabinet 21 serves as the final aggregation point, facilitating centralized management and monitoring, simplifying system operation and maintenance. This structural design also enhances the system's flexibility and scalability, making it easier to increase the number of photovoltaic units 1 or adjust the system configuration according to actual needs.

[0029] In one embodiment of the present invention, see Figure 2 The confluence device 2 includes a plurality of grid cabinets 21 , each grid cabinet 21 is connected in parallel, and each grid cabinet 21 is connected to a plurality of first confluence boxes 23 .

[0030] In this embodiment, the design of the convergence device 2 adopts a plurality of grid-connected cabinets 21 connected in parallel to achieve efficient collection of electric energy. Each grid-connected cabinet 21 is connected to a plurality of first combiner boxes 23 to form a layered electric energy collection architecture. In specific implementation, each photovoltaic unit 1 is first connected to an inverter 22 to convert direct current into alternating current, and then connected to the corresponding first combiner box 23. The electric energy of multiple photovoltaic units 1 is collected through their respective first combiner boxes 23 and then connected to the same grid-connected cabinet 21. Multiple grid-connected cabinets 21 are connected in parallel, and finally the collected electric energy is uniformly connected to the boost grid-connected device 3. For example, in a rural distributed photovoltaic system 100, it is assumed that the system has a total of 40 photovoltaic units 1, and each photovoltaic unit 1 is connected to an inverter 22. These photovoltaic units 1 are divided into 4 groups, with 10 photovoltaic units 1 in each group. The electric energy of each group of photovoltaic units 1 is collected through 10 first junction boxes 23 and then connected to a grid-connected cabinet 21. Four grid-connected cabinets 21 are connected in parallel, and finally all the electric energy is collected and connected to the boost grid-connected device 3. This layered convergence architecture can effectively manage the electric energy collection of a large number of photovoltaic units 1 and ensure the efficient operation of the system. Through the parallel connection of multiple grid-connected cabinets 21, the system can be flexibly expanded to meet the needs of photovoltaic power stations of different sizes. Each grid-connected cabinet 21 is connected to multiple first junction boxes 23, making the electric energy collection process more efficient, reducing line losses, and improving the overall efficiency of the system. This design improves the reliability and flexibility of the system. When a grid-connected cabinet 21 or a first junction box 23 fails, the system can quickly switch to other grid-connected cabinets 21 to ensure the continuous supply of electric energy and reduce the impact on the entire system.

[0031] In one embodiment of the present invention, see Figure 2 The primary equipment prefabricated cabin 31 has a second combiner box 311 , and the second combiner box 311 connects each power cabinet 21 and the primary equipment prefabricated cabin 31 .

[0032] In one embodiment, a second combiner box 311 is provided within the primary equipment prefabricated compartment 31 to further aggregate the electrical energy transmitted from each grid cabinet 21 and connect it to the booster equipment within the primary equipment prefabricated compartment 31. In specific implementation, each grid cabinet 21 is connected to the second combiner box 311 via a high-voltage cable. The second combiner box 311 aggregates the electrical energy from multiple grid cabinets 21 and transmits it to the transformer within the primary equipment prefabricated compartment 31 for boosting. For example, in a rural distributed photovoltaic power station, assume that the system has four grid cabinets 21, each connected to ten first combiner boxes 23, which aggregate the electrical energy from multiple photovoltaic cells 1. These grid cabinets 21 are connected to the second combiner box 311 within the primary equipment prefabricated compartment 31 via high-voltage cables. The second combiner box 311 aggregates the electrical energy from the four grid cabinets 21 and connects it to the transformer for boosting, ultimately boosting the electrical energy to a voltage level suitable for connection to the high-voltage power grid (e.g., 10 kV or higher). This design makes the collection and boosting of electric energy more efficient and orderly, ensuring the stable operation of the system. As an intermediate link, the second junction box 311 further concentrates the electric energy of each grid cabinet 21, reducing the line complexity and line loss between the grid cabinet 21 and the boosting equipment. This design enhances the flexibility and scalability of the system. When it is necessary to add a photovoltaic unit 1 or a grid cabinet 21, it is only necessary to connect the newly added grid cabinet 21 to the second junction box 311, without the need to make large-scale changes to other equipment in the primary equipment prefabricated cabin 31. The setting of the second junction box 311 also improves the reliability of the system. If a grid cabinet 21 fails, the electric energy of other grid cabinets 21 can still be normally collected and transmitted through the second junction box 311, ensuring the continuous operation of the system. For example, in actual operation, if a grid cabinet 21 fails, the system can automatically switch and continue to supply power through other grid cabinets 21, reducing the impact on the power grid.

[0033] In one embodiment of the present invention, see Figure 2 Each first combiner box 23 is provided with a first circuit breaker, and the second combiner box 311 is provided with a second circuit breaker. The first circuit breaker and the second circuit breaker are both electrically connected to the secondary equipment prefabricated cabin 4.

[0034] In this embodiment, each first combiner box 23 is equipped with a first circuit breaker to protect the power transmission line of the photovoltaic unit 1. Simultaneously, a second circuit breaker is installed in the second combiner box 311 to protect the power transmission line from each grid cabinet 21 to the primary equipment prefabricated cabin 31. These circuit breakers are electrically connected to the secondary equipment prefabricated cabin 4 via a communication line, enabling remote monitoring and control. In specific implementations, the first circuit breaker in each first combiner box 23 can detect abnormal current conditions in the photovoltaic unit 1, such as overload or short circuit, and disconnect the circuit when necessary to protect the photovoltaic unit 1 and related equipment. The second circuit breaker in the second combiner box 311 can detect abnormal conditions in the power transmission line from the grid cabinet 21, ensuring the safe transmission of power to the primary equipment prefabricated cabin 31. For example, in a rural distributed photovoltaic power station, assume that the system has 40 photovoltaic units 1, each of which is connected to a first combiner box 23, and each first combiner box 23 is equipped with a first circuit breaker with a rated current of 100A. The electrical energy from these first junction boxes 23 is collected by four grid-connected cabinets 21. Each grid-connected cabinet 21 is connected to a second junction box 311, which contains a second circuit breaker with a rated current of 400A. The secondary equipment prefabricated cabin 4 monitors the status of these circuit breakers in real time through a communication module. Once an anomaly is detected, the opening and closing of the circuit breakers can be remotely controlled to ensure the safe operation of the system. When a current anomaly is detected, the circuit breaker can quickly cut off the circuit to prevent equipment damage and safety accidents. In actual operation, if a photovoltaic unit 1 suffers a short circuit fault, the first circuit breaker can cut off the circuit within milliseconds to protect the photovoltaic panels and inverter 22 from damage. The electrical connection between these circuit breakers and the secondary equipment prefabricated cabin 4 enables remote monitoring and control functions, improving the intelligence level and operation and maintenance efficiency of the system. The secondary equipment prefabricated cabin 4 can obtain the status information of the circuit breakers in real time and remotely operate the circuit breakers when necessary, reducing the workload and time cost of on-site maintenance.

[0035] In one embodiment of the present invention, see Figure 2 The boost grid-connected device 3 includes a low-voltage cabinet, a transformer and a high-voltage cabinet. The low-voltage cabinet is connected in series with the transformer and the high-voltage cabinet in sequence. The low-voltage cabinet is connected to the confluence device 2. The electric energy collected by the confluence device 2 can be transmitted to the low-voltage cabinet.

[0036] In one embodiment, the booster grid-connected device 3 is a key component for converting low-voltage electricity to high-voltage and connecting it to the grid. The booster grid-connected device 3 comprises a low-voltage cabinet, a transformer, and a high-voltage cabinet, which are connected in series. The low-voltage cabinet is connected to the converging device 2 and receives the electricity collected by the converging device 2. The converging device 2 aggregates the electricity from multiple photovoltaic cells 1 and transmits it to the low-voltage cabinet via a low-voltage cable. The low-voltage cabinet is equipped with circuit breakers and protective devices for preliminary processing and protection of the collected electricity. The electricity is then transmitted from the low-voltage cabinet to the transformer, which boosts the low-voltage energy to a voltage level suitable for connection to the high-voltage grid. The boosted energy is then connected to the high-voltage grid via the high-voltage cabinet. For example, in a rural distributed photovoltaic power station, assuming the energy collected by the converging device 2 is 400V AC, it is transmitted through the low-voltage cabinet to the transformer, which boosts the voltage to 10kV. The voltage is then connected to the 10kV high-voltage grid via the high-voltage cabinet. This design ensures efficient transmission and safe connection of electricity. By sequentially connecting low-voltage cabinets, transformers, and high-voltage cabinets in series, the system efficiently boosts low-voltage power to high voltage, meeting the requirements for high-voltage grid access. This design reduces losses during power transmission and improves overall system efficiency. Protection devices within the low-voltage and high-voltage cabinets monitor abnormalities during power transmission, such as overloads and short circuits, in real time and initiate timely protective measures to ensure safe system operation. As the system expands, transformer capacity can be increased or multiple transformers can be connected in parallel to meet increased power transmission requirements. This design not only improves system reliability and cost-effectiveness but also provides strong support for the large-scale deployment and application of distributed photovoltaic power plants.

[0037] In one embodiment of the present invention, see Figure 2 A metering device 5 is further provided between the distributed photovoltaic system 100 and the main line. The metering device 5 is used to measure the electric energy transmitted from the high-voltage cabinet to the main line.

[0038] In this embodiment, the metering device 5 is an important component connecting the boost grid-connected device 3 to the main line, and is used to accurately measure the electrical energy transmitted from the high-voltage cabinet to the main line. The metering device 5 is installed between the high-voltage cabinet and the main line. It collects the current and voltage signals of the high-voltage line through current transformers and voltage transformers, and measures the electrical energy using an energy meter. For example, in a rural distributed photovoltaic power station, assuming the system uses a 10kV high-voltage grid connection, the electrical energy output by the high-voltage cabinet is connected to the metering device 5 through current transformers and voltage transformers. The metering device 5 uses a high-precision intelligent energy meter that can collect electrical energy data in real time and transmit the data to the secondary equipment prefabricated cabin 4 via a communication module. The secondary equipment prefabricated cabin 4 can analyze and manage the metering data, achieving accurate statistics and monitoring of the photovoltaic power station's power generation. In addition, the metering device 5 can be configured for bidirectional metering, measuring both the electrical energy transmitted from the photovoltaic power station to the grid and the electrical energy transmitted from the grid to the photovoltaic power station, providing accurate data support for grid operation and settlement. By precisely measuring the energy transmitted from the high-voltage cabinets to the main line, the system provides grid operators and PV plant owners with accurate power generation data, facilitating electricity billing and subsidy calculations. The bidirectional metering function of Metering Device 5 enables real-time monitoring of energy exchange between the grid and the PV plant, helping to optimize grid operation strategies and PV plant generation scheduling.

[0039] In one embodiment of the present invention, see Figure 2 The primary equipment prefabricated cabin 31 is equipped with reactive compensation device, incoming line cabinet, station transformer cabinet, PT cabinet, metering cabinet and outgoing line cabinet.

[0040] In one embodiment, a variety of key equipment are integrated into the primary equipment prefabricated cabin 31 to ensure the efficient transmission of electric energy and the stable operation of the power grid. Specifically, the primary equipment prefabricated cabin 31 is equipped with a reactive power compensation device, an incoming line cabinet, a station transformer cabinet, a PT cabinet, a metering cabinet, and an outgoing line cabinet. The reactive power compensation device is used to compensate for the reactive power in the system and improve the power factor; the incoming line cabinet is connected to the high-voltage power grid and receives external power; the station transformer cabinet provides low-voltage power to the equipment in the prefabricated cabin; the PT cabinet (voltage transformer cabinet) is used to measure the voltage of the high-voltage line; the metering cabinet is used to accurately measure electric energy; and the outgoing line cabinet outputs electric energy to the main line. For example, in a 10kV distributed photovoltaic power station, the reactive power compensation device in the primary equipment prefabricated cabin 31 uses a static var generator (SVG) with a capacity of ±5Mvar, which can dynamically adjust the reactive power to ensure that the power factor is maintained above 0.95. The incoming line cabinet is connected to the 10kV grid via high-voltage switchgear. The station transformer cabinet steps down the 10kV voltage to 380V to power the control and protection equipment within the prefabricated cabin. The voltage transformer within the PT cabinet converts the 10kV voltage to 100V for metering and protection devices. A high-precision energy meter is installed in the meter cabinet to measure the power entering and leaving the prefabricated cabin. The outgoing line cabinet outputs power to the main line via high-voltage switchgear, ensuring stable power transmission. The installation of a reactive power compensation device effectively improves power quality, enhances the power factor, and reduces grid losses. For example, in actual operation, the dynamic adjustment of the SVG enables the system to maintain a stable power factor above 0.95, significantly reducing the impact of reactive power on the grid. Furthermore, the configuration of the incoming line cabinet and station transformer cabinet ensures stable power supply to the equipment within the prefabricated cabin, enhancing system reliability. The high-precision measurement capabilities of the PT cabinet and meter cabinet provide accurate data support for grid operation and energy billing. The rational design of the outgoing line cabinet ensures efficient power output and reduces transmission losses. This integrated design also improves the compactness and scalability of the prefabricated cabin, facilitating system maintenance and upgrades. For example, when reactive power compensation capacity needs to be increased, simply replace or add the SVG device within the prefabricated cabin, eliminating the need for major modifications to other equipment. This design not only improves the overall performance and cost-effectiveness of the system but also provides strong guarantees for the efficient operation of distributed PV power plants and stable grid access.

[0041] In one embodiment of the present invention, see Figure 2 The secondary equipment prefabricated cabin 4 is equipped with remote communication, integrated protection screen, power grid dispatching host and automatic control host.

[0042] In this embodiment, the secondary equipment prefabricated cabin 4 is the core unit for realizing intelligent management and control of the system. The secondary equipment prefabricated cabin 4 integrates telecontrol communication equipment, integrated protection screen, grid dispatching host and automatic control host. The telecontrol communication equipment is connected to the external grid dispatching center through optical fiber or wireless communication module to transmit photovoltaic system operation data and receive dispatching instructions in real time. The integrated protection screen has a variety of built-in protection devices, which can protect photovoltaic units, confluence devices and boost grid-connected devices from overcurrent, short circuit, overvoltage and other faults. The grid dispatching host is responsible for receiving the dispatching instructions transmitted by the telecontrol communication equipment and performing overall dispatching and management of the system according to the instructions. The automatic control host adjusts the output power of the photovoltaic unit, the operating status of the inverter and the parameters of the boost grid-connected device in real time according to the preset control strategy.

[0043] By integrating telecontrol communications, an integrated protection screen, a grid dispatching host, and an automatic control host within the secondary equipment prefabricated cabin 4, this invention significantly enhances the intelligence and operational stability of distributed photovoltaic systems. Telecontrol communications equipment enables real-time data exchange between the photovoltaic system and the grid dispatching center, enabling the system to rapidly respond to grid dispatch instructions and improving the flexibility and reliability of grid operation. The integrated protection screen provides comprehensive fault protection for the system, effectively preventing equipment damage and grid accidents caused by faults and ensuring safe system operation. The coordinated operation of the grid dispatching host and the automatic control host enables refined management and control of the photovoltaic power station, improving power generation efficiency and power quality. For example, during peak load periods, the grid dispatching host can instruct the photovoltaic power station to increase output power. When light intensity fluctuates, the automatic control host can adjust inverter parameters in real time to ensure that the photovoltaic power station always operates at optimal levels. This highly integrated secondary equipment prefabricated cabin 4 not only improves overall system performance but also reduces operation and maintenance costs and complexity, providing strong support for the widespread application of distributed photovoltaic systems.

[0044] The present invention further provides a power grid system comprising a main line and at least two distributed photovoltaic systems 100. The specific structure of the distributed photovoltaic systems 100 is similar to that of the aforementioned embodiments. Since the present power grid system utilizes all of the technical solutions of all of the aforementioned embodiments, it at least possesses all of the beneficial effects provided by the technical solutions of the aforementioned embodiments, and therefore, no further description is given herein. Each distributed photovoltaic system 100 is connected to the main line, and each distributed photovoltaic system 100 is spaced apart from the main line.

[0045] The above are merely exemplary embodiments of the present invention and are not intended to limit the patent scope of the present invention. Any equivalent structural transformations made using the contents of the present invention's description and drawings under the technical concept of the present invention, or direct / indirect application in other related technical fields, are included in the patent protection scope of the present invention.

Claims

1. A distributed photovoltaic system, characterized in that: include: A plurality of dispersed photovoltaic units (1), each of which is capable of converting solar energy into electrical energy; A converging device (2), the converging device (2) being connected to a conductor of each photovoltaic unit (1), the converging device (2) being used to converge the electrical energy generated by a plurality of dispersed photovoltaic units (1); A boosting and grid-connected device (3), the boosting and grid-connected device (3) is used to boost low-voltage electric energy to high voltage and connect the electric energy to the high-voltage power grid, the boosting and grid-connected device (3) comprises a primary equipment prefabricated cabin (31), the confluence device (2) is connected to the primary equipment prefabricated cabin (31); and A secondary equipment prefabricated cabin (4), wherein the secondary equipment prefabricated cabin (4) is electrically connected to the confluence device (2) and the primary equipment prefabricated cabin (31); The primary equipment prefabricated cabin (31) is used for the transmission, distribution and control of electric energy; and the secondary equipment prefabricated cabin (4) is used for the monitoring, protection, control and communication of electric energy.

2. The distributed photovoltaic system according to claim 1, characterized in that: An inverter (22) is provided between each photovoltaic unit (1) and a confluence device (2); the confluence device (2) comprises a grid-connected cabinet (21) and a plurality of first confluence boxes (23); a photovoltaic unit (1) is sequentially connected to an inverter (22), a first confluence box (23) and the grid-connected cabinet (21); the first confluence boxes (23) are connected in series, and the inverters (22) are connected in parallel.

3. The distributed photovoltaic system according to claim 2, characterized in that: The confluence device (2) comprises a plurality of grid-connected cabinets (21), each of the grid-connected cabinets (21) is connected in parallel, and each of the grid-connected cabinets (21) is connected to a plurality of the first confluence boxes (23).

4. The distributed photovoltaic system according to claim 3, wherein: The primary equipment prefabricated cabin (31) has a second junction box (311), and the second junction box (311) connects each of the grid cabinets (21) and the primary equipment prefabricated cabin (31).

5. The distributed photovoltaic system according to claim 4, characterized in that: Each of the first junction boxes (23) is provided with a first circuit breaker, and each of the second junction boxes (311) is provided with a second circuit breaker. The first circuit breakers and the second circuit breakers are both electrically connected to the secondary equipment prefabricated cabin (4).

6. The distributed photovoltaic system according to any one of claims 1 to 5, characterized in that: The boost grid-connected device (3) comprises a low-voltage cabinet, a transformer, and a high-voltage cabinet. The low-voltage cabinet is connected in series with the transformer and the high-voltage cabinet in sequence. The low-voltage cabinet is connected to the confluence device (2). The electric energy collected by the confluence device (2) can be transmitted to the low-voltage cabinet.

7. The distributed photovoltaic system according to claim 6, characterized in that: A metering device (5) is further provided between the distributed photovoltaic system and the main line, and the metering device (5) is used to measure the electric energy transmitted from the high-voltage cabinet to the main line.

8. The distributed photovoltaic system according to any one of claims 1 to 5, characterized in that: The primary equipment prefabricated cabin (31) is provided with a reactive power compensation device, an incoming line cabinet, a station transformer cabinet, a PT cabinet, a metering cabinet, and an outgoing line cabinet.

9. The distributed photovoltaic system according to any one of claims 1 to 5, characterized in that: The secondary equipment prefabricated cabin (4) is provided with telecontrol communication, a comprehensive protection screen, a power grid dispatching host and an automatic control host.

10. A power grid system, characterized in that: include: Main line; and At least two distributed photovoltaic systems according to any one of claims 1 to 9, each of the distributed photovoltaic systems is connected to the main line, and each of the distributed photovoltaic systems is arranged at intervals from the main line.

Images