Multi-stage distributed photovoltaic power generation integration system based on countercurrent prevention

Abstract

The utility model discloses a multi-stage distributed photovoltaic power generation integration system based on countercurrent prevention, which comprises a photovoltaic power generation assembly, a photovoltaic inverter, a photovoltaic grid-connected cabinet, a user transformer, an II-section bus, a countercurrent prevention segmented metering cabinet, an I-section bus and a power supply special line which are connected in sequence, the photovoltaic inverter is connected with the anti-countercurrent sectional metering cabinet through the power control system cabinet; the I-section bus and the II-section bus are user high-voltage bus sections corresponding to different power generation modes respectively; and the anti-countercurrent sectional metering cabinet is used for preventing the electric quantity of the section II bus from being fed to the section I bus. According to the utility model, through cooperation of the anti-countercurrent segmented metering cabinet and the power control system cabinet, the electric energy flow direction is accurately controlled, and electricity mixing is solved; the buses in different power generation modes meet the requirements of multiple enterprises, the limitation of special lines is broken through, the flexibility and compatibility of equipment connection and bus extension are improved, and the resource utilization rate is improved.

Description

TECHNICAL FIELD

[0001] The utility model relates to photovoltaic power generation technical field especially relates to a kind of multi-period distributed photovoltaic power generation integration system based on anti-reverse flow. BACKGROUND

[0002] The statements in this part are merely provided with the background technical information related to the utility model, and do not necessarily constitute prior art.

[0003] Distributed photovoltaic power generation system refers to a kind of electronic components such as single-crystal silicon solar panel, inverter, current combiner box, grid-connected cabinet, which can be connected with power grid, and carries out bidirectional power transmission with power grid.

[0004] With the development of distributed photovoltaic power generation system, some problems of industrial and commercial distributed photovoltaic power generation system are gradually found, for example, a power supply special line of industrial and commercial users usually cannot meet the grid-connected power generation demand of two photovoltaic power generation enterprises: once the first photovoltaic power generation enterprise registers and occupies the power supply special line, due to the capacity limitation of the power supply special line and the incompatibility of original anti-reverse flow system and other related equipment configuration, the second photovoltaic power generation enterprise cannot handle grid access approval procedures, which leads to the failure to use the power supply special line for grid-connected power generation, and further cannot realize the coexistence of multi-period photovoltaic power generation projects of different photovoltaic enterprises on the same power supply special line. Even though the two enterprises can share a power supply special line in theory, the grid-connected power generated by them will be confused, so that the power supply company cannot accurately distinguish the grid-connected power of the two enterprises. Therefore, industrial and commercial users cannot effectively utilize a large number of idle rooftops, and new energy development is trapped in a bottleneck. UTILITY MODEL CONTENT

[0005] In order to solve the technical problems in the background art, the utility model provides a kind of multi-period distributed photovoltaic power generation integration system based on anti-reverse flow, through the cooperative operation of anti-reverse flow segmented metering cabinet and power control system cabinet, the flow direction of electric energy can be accurately controlled, the grid-connected power confusion problem is effectively solved, so that the power supply company can distinguish the power of different enterprises. Secondly, the busbars of section I and section II correspond to different power generation modes, which can meet the needs of different photovoltaic enterprises, and break through the limitation that the power supply special line cannot coexist with multi-period projects.

[0006] In order to achieve the above purpose, the utility model adopts the following technical solutions:

[0007] A kind of multi-period distributed photovoltaic power generation integration system based on anti-reverse flow, including photovoltaic power generation component, photovoltaic inverter, photovoltaic grid-connected cabinet, user transformer, section II busbar, anti-reverse flow segmented metering cabinet, section I busbar and power supply special line connected in sequence, the photovoltaic inverter and anti-reverse flow segmented metering cabinet are connected by power control system cabinet;

[0008] The I-section busbar and the II-section busbar are respectively user high-voltage busbar sections corresponding to different power generation modes;

[0009] The anti-backflow segmented metering cabinet is used to prevent the power from the II section busbar from feeding into the I section busbar.

[0010] In one implementation, the I-section busbar and the II-section busbar correspond to the Phase I photovoltaic project and the Phase II photovoltaic project, respectively.

[0011] As one implementation method, the power generation mode of the I-section bus is self-consumption with surplus power fed into the grid.

[0012] As one implementation method, the power generation mode of the II section bus is self-consumption, with surplus power not being fed into the grid.

[0013] In one implementation, the photovoltaic inverter, photovoltaic grid-connected cabinet, user transformer, section II busbar, and anti-reverse current segmented metering cabinet are bidirectionally connected; section I busbar is unidirectionally connected to the anti-reverse current segmented metering cabinet and the dedicated power supply line.

[0014] In one implementation, the anti-reverse current segmented metering cabinet includes a current transformer and a unidirectional energy metering device for assessing reverse power consumption.

[0015] In one implementation, the power control system cabinet is used to collect the grid-connected load power and the total power of the inverter of the photovoltaic power generation system, and to determine the active power target value of the photovoltaic inverter by calculating the difference between the grid-connected load power and the preset power.

[0016] In one implementation, the power control system cabinet is also used to adjust the power of the photovoltaic inverter according to the power of the anti-reverse current segmented metering cabinet.

[0017] In one implementation, the I-section busbar and the II-section busbar each include multiple segmented busbars to achieve the expansion of the segmented busbars.

[0018] In one implementation, the photovoltaic inverter and the anti-reverse current segmented metering cabinet are respectively connected to the power control system cabinet through an optical fiber communication unit.

[0019] Compared with the prior art, the beneficial effects of this disclosure are as follows:

[0020] (1) This utility model relates to the field of industrial and commercial distributed photovoltaic power generation. It is an optimization and improvement of a single power supply line for industrial and commercial users to meet the grid connection of multiple photovoltaic power generation projects of different photovoltaic enterprises. Through the anti-reverse current power control system, multiple photovoltaic power generation projects of different photovoltaic enterprises can coexist on the same power supply line.

[0021] (2) This utility model integrates the distributed photovoltaic power generation anti-reverse current power control system with the user's internal power grid into a whole, reducing the technical requirements and engineering difficulty of construction, and also reducing the overall system cost. The distributed photovoltaic power generation anti-reverse current power control system has a fast response speed, timely control, good real-time performance, and convenient operation, making the whole system more economical and having great market application value.

[0022] (3) The specific connection method between the various devices and the scalability of the busbar in this utility model not only improve the system's flexibility and compatibility, but also make full use of the vacant rooftops of industrial and commercial buildings, promote the development of new energy, and break through development bottlenecks. Attached Figure Description

[0023] The accompanying drawings, which form part of this disclosure, are used to provide a further understanding of this disclosure. The illustrative embodiments of this disclosure and their descriptions are used to explain this disclosure and do not constitute a limitation thereof.

[0024] Figure 1 This is a schematic diagram of a multi-phase distributed photovoltaic power generation integration system based on anti-backflow provided in Embodiment 1 of this disclosure;

[0025] Figure 2 This is a wiring diagram of a multi-phase distributed photovoltaic power generation integration system based on anti-backflow provided in Embodiment 1 of this disclosure. Detailed Implementation

[0026] The present disclosure will be further described below with reference to the accompanying drawings and embodiments.

[0027] It should be noted that the following detailed descriptions are exemplary and intended to provide further illustration of this disclosure. Unless otherwise specified, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this disclosure pertains.

[0028] Example 1

[0029] like Figure 1 As shown, this embodiment provides a multi-phase distributed photovoltaic power generation integration system based on anti-reverse current, including photovoltaic power generation modules, photovoltaic inverters, photovoltaic grid-connected cabinets, user transformers, Section II busbars, anti-reverse current segmented metering cabinets, Section I busbars, and dedicated power supply lines connected in sequence. The photovoltaic inverters and the anti-reverse current segmented metering cabinets are connected through a power control system cabinet. Section I and Section II busbars are user high-voltage busbar segments corresponding to different power generation modes, and Section I and Section II busbars correspond to Phase I and Phase II photovoltaic projects, respectively. The anti-reverse current segmented metering cabinet is used to prevent the power from Section II busbars from feeding power back to Section I busbars.

[0030] In this embodiment, the power generation mode of bus section I is configured as self-consumption with surplus power fed into the grid.

[0031] Specifically, Section I busbar is unidirectionally connected to the anti-backflow sectional metering cabinet and the dedicated power supply line, meaning that Section I busbar unidirectionally outputs electrical energy to the anti-backflow sectional metering cabinet and the dedicated power supply line.

[0032] In this connection mode, the electricity generated by the Phase I photovoltaic project is first transmitted to the Phase I busbar. The electricity is then transmitted through the Phase I high-voltage busbar to the user's internal load, allowing the user's internal electrical equipment to directly utilize the electricity generated by the Phase I photovoltaic project, meeting their own electricity needs. When the photovoltaic power on the user side is saturated, meaning the user's internal load needs have been met, and there is still surplus electricity, the Phase I busbar unidirectionally outputs electricity to the dedicated power supply line, realizing the surplus electricity being fed into the grid. This process, through the unidirectional connection, ensures that electricity can only flow in the prescribed direction, from the Phase I busbar to the dedicated power supply line, transmitting excess electricity to the external power grid.

[0033] In this embodiment, the power generation mode of the II section bus is self-generation and self-consumption, with surplus power not being fed into the grid.

[0034] Specifically, the photovoltaic power generation modules point unidirectionally to the photovoltaic inverter, while the photovoltaic inverter, photovoltaic grid-connected cabinet, user transformer, Section II busbar, and anti-reverse current segmented metering cabinet are bidirectionally connected.

[0035] In this connection mode, the electricity generated by the Phase II photovoltaic project, apart from the load on the low-voltage busbar itself, is transmitted to the Section II busbar via the user-side transformer and is limited to use on the Section II high-voltage busbar. The bidirectional connection allows for the rational distribution of electrical energy among the relevant equipment on the Section II busbar, meeting internal load demands. Furthermore, the presence of the anti-reverse flow segmented metering cabinet prevents electrical energy from flowing to the Section I busbar.

[0036] This embodiment, by distinguishing between bidirectional and unidirectional connections, can precisely control the direction of power flow. The anti-reverse flow segmented metering cabinet prevents the power from flowing from the second-section busbar to the first-section busbar and the dedicated power supply line, ensuring the independence of power in each section of the busbar. This ensures that the power generated by the two companies will not be mixed, meeting the needs of different power generation modes corresponding to different busesbars. Thus, it enables multiple phases of photovoltaic power generation projects of different photovoltaic companies to coexist on the same dedicated power supply line.

[0037] The photovoltaic power generation modules commonly use monocrystalline silicon and polycrystalline silicon as materials. After processes such as ingot casting, ingot breaking, and slicing, silicon wafers are produced for further processing. Trace amounts of boron and phosphorus are doped and diffused onto the silicon wafers to form PN junctions. Then, finely prepared silver paste is screen-printed onto the silicon wafers to create grid lines. After sintering, the back electrode is formed, and an anti-reflective coating is applied to the side with the grid lines, thus completing the cell. The cells are arranged and combined to form a battery module, which is a large circuit board. Typically, an aluminum frame surrounds the module, the front is covered with glass, and electrodes are mounted on the back. With the battery module and other auxiliary equipment, a power generation system can be assembled.

[0038] In this specific embodiment, the anti-reverse current segmented metering cabinet includes a current transformer and a unidirectional energy metering device, which is used to assess the reverse power consumption.

[0039] Current transformers are primarily responsible for collecting current signals in the power line. Their high-precision current sensing capability allows for accurate acquisition of current data changes during power transmission. One-way energy metering devices, based on the current data collected by the current transformers and combined with their own energy metering algorithms, accurately measure and analyze the direction and amount of energy flow, specifically recording and judging one-way energy flow. The power supply department provides the necessary equipment for both current transformers and one-way energy metering devices. The equipment is sealed to prevent human intervention, and the power supply department regularly inspects its integrity. The one-way energy metering devices are equipped with communication terminals connected to the power grid system, allowing the power supply department to view data in real time. When reverse energy flow occurs, the one-way energy metering device, based on the abnormal current data transmitted from the current transformers, analyzes and processes the data internally, issues an alarm signal, and uploads the signal to the power supply department. The power supply department simultaneously notifies the photovoltaic power generation company, which then investigates the cause. The power grid's backend system automatically records the reverse energy flow data, and during the monthly power grid settlement, the photovoltaic power generation company is assessed and penalized based on the amount of reverse energy flow.

[0040] The synergistic effect of the current transformer and the unidirectional energy metering device in the anti-reverse flow segmented metering cabinet can distinguish the direction of energy flow, thereby ensuring that the on-grid electricity generated by the two companies sharing a dedicated power supply line will not be confused when the I-section busbar and the II-section busbar are connected to two companies respectively.

[0041] In this specific embodiment, the power control system cabinet is used to collect the grid-connected load power and the total power of the inverter of the photovoltaic power generation system. By calculating the difference between the grid-connected load power and the preset power, the active power target value of the photovoltaic inverter is determined.

[0042] Furthermore, the power control system cabinet dynamically tracks the load power of the anti-reverse current segmented metering cabinet and sends signals to the photovoltaic inverters based on the tracked load power to adjust the output power of each photovoltaic inverter, ensuring that the total power generation does not exceed the load power of the anti-reverse current segmented metering cabinet. When the power control system cabinet detects reverse power in the anti-reverse current segmented metering cabinet, it sends signals to the photovoltaic inverters, progressively shutting down one or more inverters until the reverse power disappears. When the load power increases, the power control system then, based on the power increase and ensuring no reverse power occurs, sequentially matches and engages the photovoltaic inverters.

[0043] The power control system cabinet determines the active power target value of the photovoltaic inverter by calculating the difference between the load power at the grid connection point and the preset power, and dynamically tracks the load power of the anti-reverse current segmented metering cabinet and adjusts the output power of the photovoltaic inverter. This ensures that the power of different enterprises is distributed according to their respective modes, prevents power confusion, and enables different phases of projects to operate according to their own power generation modes, thus ensuring the coexistence of multiple phases of projects.

[0044] like Figure 2 The wiring diagram shown in this embodiment illustrates that, in the event of demand from industrial and commercial users, the user busbar can be divided into sections I and II, as well as sections III, IV, and V, to meet the grid connection and power generation needs of multiple photovoltaic enterprises and their various phases of photovoltaic power generation projects, thus contributing to the rapid development of new energy.

[0045] When a new photovoltaic (PV) company connects to the network, its power generation mode requirements can be met by expanding the number of segmented busbars in section I or section II to connect it to the corresponding busbar. During the connection process, the anti-reverse current segmented metering cabinet ensures that the power flow of the newly connected company conforms to the power generation mode requirements of its busbar, preventing interference with the power flow of the original system and thus ensuring the stable operation of the entire system.

[0046] In one specific implementation, the photovoltaic inverter and the anti-reverse current segmented metering cabinet are respectively connected to the power control system cabinet via fiber optic communication units. The fiber optic communication units are used to achieve high-speed and stable data transmission between the photovoltaic inverter, the power control system cabinet, and the anti-reverse current segmented metering cabinet, ensuring the accurate transmission of system control commands and monitoring data.

[0047] In this embodiment, the anti-reverse current segmented metering cabinet, besides preventing power from the second-stage busbar from feeding back to the first-stage busbar, serves as a key node to enable the coexistence of multiple photovoltaic projects and ensure clear power calculation. Through its internal current transformers and unidirectional power metering devices, it can accurately assess reverse power and differentiate the power consumption of different phases of the project. Simultaneously, combined with the power control system cabinet, it can rationally adjust the photovoltaic inverter power, ensuring that each phase of the project operates according to its own mode, such as feeding surplus power from the first stage to the grid while keeping surplus power from the second stage off the grid, avoiding power confusion and improving system operating efficiency and management convenience.

[0048] Working principle: such as Figure 2 As shown, the Phase II photovoltaic project utilizes user-side transformers for low-voltage grid-connected operation. The generated electricity, besides being used by the loads on the low-voltage busbar itself, is transmitted to the Phase II busbar via the user-side transformer. The photovoltaic power generated on the Phase II busbar is limited to use on the Phase II high-voltage busbar and is then transmitted to other internal loads of the user. Due to the blocking effect of the anti-reverse current segmented metering cabinet, the photovoltaic power generated on the Phase II busbar cannot be fed back to the Phase I busbar. The Phase I photovoltaic project utilizes its own step-up device for high-voltage grid-connected operation via the Phase I photovoltaic grid-connected switch. The generated electricity is transmitted to the Phase I busbar and then to the internal loads of the user through the Phase I high-voltage busbar. It can also be transmitted to the loads on the Phase II busbar through the anti-reverse current segmented metering cabinet. When the user-side photovoltaic power is saturated, the surplus photovoltaic power from Phase I is fed back to the grid through a dedicated power supply line.

[0049] In this embodiment, the anti-reverse flow segmented metering cabinet ensures that Phase I and Phase II projects correspond to different busbars and have different power flow rules, enabling projects from different phases to coexist on the same dedicated power supply line. By setting clear power flow directions and equipment functions, the system can achieve the coexistence of multiple phase projects and power differentiation without relying on complex structures, thus reducing the cost of multi-phase distributed photovoltaic power generation integration systems.

[0050] The above description is merely a preferred embodiment of this utility model and is not intended to limit the utility model. Various modifications and variations can be made to this utility model by those skilled in the art. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of this utility model should be included within the protection scope of this utility model.

Claims

1. A multi-phase distributed photovoltaic power generation integration system based on anti-backflow, characterized in that, It includes photovoltaic power generation components, photovoltaic inverter, photovoltaic grid-connected cabinet, user transformer, section II bus, anti-reverse current segmented metering cabinet, section I bus and dedicated power supply line connected in sequence. The photovoltaic inverter and anti-reverse current segmented metering cabinet are connected through a power control system cabinet. The I-section busbar and the II-section busbar are respectively user high-voltage busbar sections corresponding to different power generation modes; The anti-backflow segmented metering cabinet is used to prevent the power from the II section busbar from feeding into the I section busbar.

2. The multi-phase distributed photovoltaic power generation integration system based on anti-backflow as described in claim 1, characterized in that, The busbar section I and busbar section II correspond to the photovoltaic project phase I and phase II, respectively.

3. The multi-phase distributed photovoltaic power generation integration system based on anti-backflow as described in claim 1, characterized in that, The power generation mode of the bus section I is self-consumption, with surplus power fed into the grid.

4. The multi-phase distributed photovoltaic power generation integration system based on anti-backflow as described in claim 1, characterized in that, The power generation mode of the II section bus is self-consumption, and the surplus power is not fed into the grid.

5. A multi-phase distributed photovoltaic power generation integration system based on anti-backflow as described in claim 1, characterized in that, The photovoltaic inverter, photovoltaic grid-connected cabinet, user transformer, section II busbar, and anti-reverse current segmented metering cabinet are bidirectionally connected; section I busbar is unidirectionally connected to the anti-reverse current segmented metering cabinet and the dedicated power supply line.

6. A multi-phase distributed photovoltaic power generation integration system based on anti-backflow as described in claim 1, characterized in that, The anti-reverse current segmented metering cabinet includes a current transformer and a unidirectional energy metering device, which is used to assess reverse power consumption.

7. A multi-phase distributed photovoltaic power generation integration system based on anti-backflow as described in claim 1, characterized in that, The power control system cabinet is used to collect the grid-connected load power and the total power of the inverter of the photovoltaic power generation system. By calculating the difference between the grid-connected load power and the preset power, the active power target value of the photovoltaic inverter is determined.

8. A multi-phase distributed photovoltaic power generation integration system based on anti-backflow as described in claim 1, characterized in that, The power control system cabinet is also used to adjust the power of the photovoltaic inverter according to the power of the anti-reverse flow segmented metering cabinet.

9. A multi-phase distributed photovoltaic power generation integration system based on anti-backflow as described in claim 1, characterized in that, The I-section busbar and the II-section busbar each contain multiple segmented busbars to achieve the expansion of the segmented busbars.

10. A multi-phase distributed photovoltaic power generation integration system based on anti-backflow as described in claim 1, characterized in that, The photovoltaic inverter and the anti-reverse current segmented metering cabinet are respectively connected to the power control system cabinet through an optical fiber communication unit.

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