Intelligent photovoltaic grid-connected cabinet

Abstract

The utility model relates to the technical field of complete switch equipment production and manufacturing and new energy power generation, in particular to an intelligent photovoltaic grid-connected cabinet, which comprises a photovoltaic grid-connected cabinet, and a low-voltage V photovoltaic grid-connected access module capable of converting direct-current electric energy into alternating-current electric energy is arranged in the photovoltaic grid-connected cabinet. The photovoltaic grid-connected cabinet is internally provided with a metering module which can be used for measuring key parameters such as generating capacity and operation efficiency of a photovoltaic system, an islanding protection module which can protect a power grid and the photovoltaic system, and an anti-countercurrent protection module which can monitor the power grid; and an SVG real-time dynamic compensation unit capable of performing reactive compensation and filtering is arranged in the photovoltaic grid-connected cabinet.

Description

Technical Field

[0001] The utility model relates to the field of production and manufacturing of complete sets of switchgear and new energy power generation technology, in particular to an intelligent photovoltaic grid-connected cabinet. Background Art

[0002] With the development of new energy, new energy such as photovoltaic and wind power will gradually evolve from the main source of incremental power generation to the main source of installed power, and vigorously develop distributed smart grids. According to 5.1.1 of "Q / GDW 11147-2017 Design Specifications for Distributed Power Access to Distribution Networks", for a single grid connection point, the voltage level to be connected should be determined after comprehensive comparison based on the principles of safety, flexibility, and economy, according to the capacity of distributed power sources, power generation characteristics, conductor current carrying capacity, upstream transformer and line acceptance capacity, and distribution network conditions in the user's area. If both high and low voltage levels have access conditions, low voltage level access shall be preferred.

[0003] With the promotion of the policy, the capacity of a single grid-connected point has been expanded to 500kW in some areas.

[0004] The rooftop photovoltaic projects of enterprises generally adopt the method of generating electricity for their own use and connecting the surplus electricity to the grid. The enterprises have configured reactive power compensation internally. The low power factor period of photovoltaic power generation generally occurs during the unstable period of photovoltaic power generation. In many current 380V photovoltaic grid-connected projects, the grid-connected cabinet only collects the AC power converted by the inverter and directly connects it to the low-voltage incoming line of the user's original power distribution (before the reactive power compensation device). The access equipment of photovoltaic new energy and the supporting reactive power compensation device are mostly connected to the user's outgoing line side. After the photovoltaic power project is connected, the power factor will not meet the standard to a certain extent, resulting in the user being fined by the power supply company for electricity fees. It may also affect the normal operation of the company's high-precision production equipment due to excessive power harmonics. Utility Model Content

[0005] 1. Technical issues to be resolved

[0006] In view of the deficiencies in the prior art, the utility model provides an intelligent photovoltaic grid-connected cabinet, which solves the problems raised in the above-mentioned background technology.

[0007] (II) Technical solution

[0008] To achieve the above purpose, the utility model is implemented through the following technical solutions: an intelligent photovoltaic grid-connected cabinet, including a photovoltaic grid-connected cabinet, a low-voltage V photovoltaic grid-connected access module for converting DC power into AC power, a metering module for measuring key parameters such as the power generation and operating efficiency of the photovoltaic system, an island protection module for protecting the power grid and the photovoltaic system, an anti-reverse flow protection module for monitoring the power grid, and an SVG real-time dynamic compensation unit for reactive power compensation and filtering. Low-voltage 400V photovoltaic grid-connected access module: responsible for converting the DC power generated by the photovoltaic power generation system into AC power and connecting it to the low-voltage 400V power grid. In this process, it is necessary to ensure that the voltage, frequency and phase match the power grid to avoid impact on the power grid. Metering module: used to measure key parameters such as the power generation and operating efficiency of the photovoltaic system, and provide data support for system monitoring and management. Through metering data, the operating status of the system can be evaluated, and problems can be discovered and solved in a timely manner. Island protection module: When the grid fails or blackouts, the photovoltaic system may continue to supply power, forming an island. The island protection device can detect the island phenomenon and promptly cut off the connection between the photovoltaic system and the grid to prevent damage to the grid and the photovoltaic system. Anti-reverse flow protection module: In some cases, the photovoltaic system may transmit reverse current to the grid, which will affect the stability and safety of the grid. The anti-reverse flow protection device can monitor the current flow in real time, and once the reverse current is detected, it will promptly cut off the connection between the photovoltaic system and the grid. SVG module: It is a power electronic device used for reactive power compensation and filtering. In the photovoltaic system, the SVG module can be used to adjust reactive power, improve the power factor of the power system, and improve the efficiency and stability of the grid. At the same time, the SVG module can also filter out harmonics in the grid and reduce the impact of harmonics on the photovoltaic system and the grid. In summary, low-voltage 400V photovoltaic grid-connected access, metering, island protection, anti-reverse flow protection and SVG modules each play an important role in the photovoltaic power generation system. The relationship between them is interrelated and mutually supportive, and they jointly ensure the safe, stable operation and efficient utilization of the photovoltaic system. In this solution, each component is modularized, so that the photovoltaic grid-connected cabinet has a high degree of integration and can improve the convenience of photovoltaic access construction and maintenance.

[0009] Furthermore, the SVG real-time dynamic compensation unit includes an SVG module, and a plurality of SVG modules are provided in the photovoltaic grid-connected cabinet.

[0010] Furthermore, the number of SVG modules provided in the photovoltaic grid-connected cabinet is less than or equal to six.

[0011] Furthermore, a fan is provided at the bottom end of the photovoltaic grid-connected cabinet, an opening and closing door is provided in the photovoltaic grid-connected cabinet, and a heat dissipation hole is provided in the opening and closing door.

[0012] Furthermore, the length of the photovoltaic grid-connected cabinet body is 1200 mm, the depth of the photovoltaic grid-connected cabinet body is 800 mm, and the height of the photovoltaic grid-connected cabinet body is 2200 mm.

[0013] Compared with the existing technology, the intelligent photovoltaic grid-connected cabinet has the characteristics of integrated grid-connected compensation, modularization, small size, intelligence and high integration. It is particularly suitable for rooftop photovoltaic grid-connected access in the limited space of the distribution room of enterprise users, ensuring that the electric energy generated by the photovoltaic power generation system can be safely, efficiently and stably connected to the public power grid and meet the relevant grid-connected technical standards and requirements. BRIEF DESCRIPTION OF THE DRAWINGS

[0014] Figure 1 It is a schematic diagram of the structure of the utility model;

[0015] Figure 2 It is a schematic diagram of the process of coordination of various modules in the photovoltaic grid-connected cabinet of the utility model;

[0016] Figure 3 This is a circuit diagram of the utility model.

[0017] In the figure: 1. Photovoltaic grid-connected cabinet; 2. Low-voltage 400V photovoltaic grid-connected access module; 3. Metering module; 4. Island protection module; 5. Anti-backflow protection module; 6. SVG real-time dynamic compensation unit; 7. SVG module; 8. Fan; 9. Opening and closing door. DETAILED DESCRIPTION

[0018] The technical solutions in the embodiments of the present invention will be described clearly and completely below in conjunction with the drawings in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, rather than all of the embodiments.

[0019] See also Figures 1 to 3The utility model provides a technical solution: an intelligent photovoltaic grid-connected cabinet, including a photovoltaic grid-connected cabinet 1, a fan 8 is provided at the bottom of the photovoltaic grid-connected cabinet 1, an opening and closing door 9 is provided in the photovoltaic grid-connected cabinet 1, and a heat dissipation hole is provided in the opening and closing door 9, two fans 8 are provided at the bottom of the photovoltaic grid-connected cabinet 1, and heat dissipation holes are provided in the front opening and closing door 9 and the rear opening and closing door 9 of the photovoltaic grid-connected cabinet 1. The length of the photovoltaic grid-connected cabinet 1 is 1200mm, the depth of the photovoltaic grid-connected cabinet 1 is 800mm, and the height of the photovoltaic grid-connected cabinet 1 is 2200mm. The photovoltaic grid-connected cabinet 1 is provided with a low-voltage 400V photovoltaic device for converting DC power into AC power. The photovoltaic grid-connected access module 2 is provided in the photovoltaic grid-connected cabinet 1, and a metering module 3 is provided for measuring key parameters such as power generation and operation efficiency of the photovoltaic system. The photovoltaic grid-connected cabinet 1 is provided with an island protection module 4 for protecting the power grid and the photovoltaic system. The photovoltaic grid-connected cabinet 1 is provided with an anti-reverse flow protection module 5 for monitoring the power grid. The photovoltaic grid-connected cabinet 1 is provided with an SVG real-time dynamic compensation unit 6 for reactive power compensation and filtering. The SVG real-time dynamic compensation unit 6 includes an SVG module 7. The photovoltaic grid-connected cabinet 1 is provided with a plurality of SVG modules 7. The number of SVG modules 7 arranged in the photovoltaic grid-connected cabinet 1 is less than or equal to six.

[0020] The electrical components mentioned in this article are all connected to an external main controller and 380V commercial power, and the main controller can be a conventional known device for control such as a computer.

[0021] The photovoltaic access point in this solution is at the user's incoming line (before the reactive power compensation device). We only need to consider the impact of the stability of photovoltaic power generation itself on the power quality, and comprehensively determine the reactive power compensation capacity to be about 15% of the photovoltaic full power generation capacity; for the large proportion of power generation, the impact of harmonics needs to be considered, and it is generally recommended to consider 10% of the harmonic current; by configuring the working mode of SVG, harmonics and reactive power can be controlled at the same time. The recommended configuration is as follows:

[0022] Recommended configuration table for PV access point before user reactive power compensation device:

[0023] Serial number Grid-connected capacity (kVA) SVG configuration capacity (kvar) 1 400～630 120 2 200~400(inclusive) 90 3 200 and below 60

[0024] At the beginning of the electricity planning and design of existing corporate photovoltaic power generation projects, the access of photovoltaic and other new energy power generation was not taken into consideration. The user's distribution room did not reserve a location for the installation of grid-connected equipment. The access equipment for photovoltaic new energy and the supporting reactive power compensation devices were mostly connected in parallel to the user's outgoing line side.

[0025] The intelligent photovoltaic grid-connected cabinet adopts standardized design according to the relevant specifications of low-voltage photovoltaic access voltage level, integrating photovoltaic grid connection, reactive power compensation and integrated terminal communication. Reactive power compensation can be configured with up to 6 pluggable 30kvar SVG modules, and the configuration of SVG modules can be increased or decreased according to the reactive power situation on site, so that a single photovoltaic grid connection is reduced from the traditional 2X800mm to 1200mm, reducing the requirements for distribution network space, reducing the one-time investment of equipment, and improving equipment maintainability. Compared with traditional photovoltaic access projects, it has the following advantages:

[0026] 1) Photovoltaic grid connection, metering and power quality management are integrated, and the reactive power compensation unit is equipped with a separate main power switch;

[0027] 2) Modularization and high integration improve the convenience of photovoltaic access construction and maintenance;

[0028] 3) The photovoltaic grid-connected specifications are standardized, and different capacity combinations are connected to the grid to improve the standardization of photovoltaic access. The reactive power compensation unit adopts a 6-module photovoltaic-specific 30kvar SVG design;

[0029] 4) With built-in current sampling CT protection function, it can prevent SVG from forming an open circuit and generating high voltage;

[0030] 5) Multi-compensation modular redundant design to improve the reliability of compensation;

[0031] 6) Photovoltaic grid-connected and compensation units can be connected to the incoming and outgoing lines respectively as needed, with local parameter setting and query functions;

[0032] 7) Equipped with multiple protections such as power generation metering and anti-islanding protection;

[0033] 8) It can be connected to the low-carbon energy management system platform, allowing enterprises to fully understand energy consumption and power quality in real time.

[0034] In the description of this specification, the terms "connect", "install", "fix", "set", etc. are understood in a broad sense. For example, "connection" can be a fixed connection or an indirect connection through an intermediate component without affecting the relationship between components and the technical effect. It can also be an integral connection or a partial connection. As in this example, for ordinary technicians in this field, the specific meanings of the above terms in this utility model or utility model can be understood according to the specific circumstances.

[0035] The above description is only a preferred specific implementation manner of the present invention, but the protection scope of the present invention is not limited thereto. Any technician familiar with the technical field can make equivalent replacements or changes within the technical scope disclosed by the present invention according to the technical scheme and the utility model concept of the present invention, which should be covered by the protection scope of the present invention.

Claims

1. An intelligent photovoltaic grid-connected cabinet, comprising a photovoltaic grid-connected cabinet (1), characterized in that: The photovoltaic grid-connected cabinet (1) is provided with a low-voltage 400V photovoltaic grid-connected access module (2) capable of converting direct current electric energy into alternating current electric energy; the photovoltaic grid-connected cabinet (1) is provided with a metering module (3) capable of measuring the power generation and key parameters of the operating efficiency of the photovoltaic system; the photovoltaic grid-connected cabinet (1) is provided with an island protection module (4) capable of protecting the power grid and the photovoltaic system; the photovoltaic grid-connected cabinet (1) is provided with an anti-reverse flow protection module (5) capable of monitoring the power grid; the photovoltaic grid-connected cabinet (1) is provided with an SVG real-time dynamic compensation unit (6) capable of performing reactive power compensation and filtering; the SVG real-time dynamic compensation unit (6) comprises an SVG module (7); and the photovoltaic grid-connected cabinet (1) is provided with a plurality of SVG modules (7).

2. The intelligent photovoltaic grid-connected cabinet according to claim 1, characterized in that: The number of SVG modules (7) provided in the photovoltaic grid-connected cabinet (1) is less than or equal to six.

3. The intelligent photovoltaic grid-connected cabinet according to claim 2, characterized in that: A fan (8) is provided at the bottom end of the photovoltaic grid-connected cabinet (1), an opening and closing door (9) is provided in the photovoltaic grid-connected cabinet (1), and a heat dissipation hole is provided in the opening and closing door (9).

4. The intelligent photovoltaic grid-connected cabinet according to claim 3, characterized in that: Two fans (8) are provided at the bottom end of the photovoltaic grid-connected cabinet (1), and heat dissipation holes are provided in the front opening and closing door (9) and the rear opening and closing door (9) of the photovoltaic grid-connected cabinet (1).

5. The intelligent photovoltaic grid-connected cabinet according to claim 4, characterized in that: The length of the photovoltaic grid-connected cabinet (1) is 1200 mm, the depth of the photovoltaic grid-connected cabinet (1) is 800 mm, and the height of the photovoltaic grid-connected cabinet (1) is 2200 mm.

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