Photovoltaic SVG dynamic compensation cabinet

Abstract

The utility model provides a photovoltaic SVG dynamic compensation cabinet, which comprises a compensation cabinet main body and a capacitor, an operation control box is arranged in the compensation cabinet main body, a high-voltage load switch is arranged above the operation control box, a vacuum contactor is arranged below the operation control box, and the capacitor is arranged above the high-voltage load switch. An SVG module is installed below the vacuum contactor and located below the left side of the compensation cabinet body, a first inversion power unit and a second inversion power unit are arranged on the right side of the operation control box side by side, a centrifugal fan is installed at one end of the top of the compensation cabinet body, and one end of the centrifugal fan is connected with an air pipe. The capacitor is located in the middle of the interior of the compensation cabinet body. According to the utility model, the SVG dynamic reactive power compensator is adopted, the power factor of a power grid can be monitored in real time, accurate reactive power compensation can be provided according to requirements, and the SVG dynamic reactive power compensator can help a photovoltaic power generation system to maintain a high power factor and improve the power generation efficiency by adjusting the phase difference between current and voltage.

Description

Technical Field

[0001] The utility model relates to the technical field of SVG dynamic compensation, and specifically discloses an SVG dynamic compensation cabinet for photovoltaics. Background Art

[0002] Photovoltaic power generation, as a clean and renewable energy form, has become an important part of the global energy transformation; the electrical system of a photovoltaic power station mainly includes photovoltaic arrays, combiner boxes, inverters, transformers and other parts, which have a direct impact on the operation of the system. In the photovoltaic array, multiple photovoltaic strings are set in parallel for power generation, and are used in series using combiner boxes; multiple photovoltaic currents are collected in the combiner box into the inverter, and then the voltage is adjusted to 270V or 315V AC line, and then directly converted to 35kV by a step-up transformer and incorporated into the corresponding power grid; step-up transformers are arranged in photovoltaic power stations to increase 35kV to 110kV and connect to the power grid.

[0003] When a photovoltaic power station is connected to the grid, the power flow distribution of the system changes. If the connected capacity is too large, the voltage at the grid point will exceed the limit. Moreover, changes in light and temperature in the external environment will also cause fluctuations in the active power output at the grid point, resulting in voltage fluctuations and grid voltage imbalance. In addition, when a grid failure occurs, the grid point voltage drops. If the photovoltaic power station has a certain reactive output, it can provide the necessary voltage support for the system. Photovoltaic inverters can generate a certain amount of reactive power, but when the sunshine intensity is sufficient, the active output of the inverter is high, and the reactive power is very small, and it may even be insufficient to compensate for the reactive power loss of the step-up transformer, resulting in a low power factor of the photovoltaic power station. For this reason, we propose an SVG dynamic compensation cabinet for photovoltaics. Utility Model Content

[0004] In view of the above-mentioned defects or deficiencies in the prior art, an SVG dynamic compensation cabinet for photovoltaics includes a compensation cabinet body and a capacitor, an operation control box is installed inside the compensation cabinet body, and a high-voltage load switch is arranged above the operation control box, a vacuum contactor is installed below the operation control box, and an SVG module is installed below the vacuum contactor and at the lower left side of the compensation cabinet body, a No. 1 inverter power unit and a No. 2 inverter power unit are arranged side by side on the right side of the operation control box, a centrifugal fan is installed at one end of the top of the compensation cabinet body, and one end of the centrifugal fan is connected to the air duct, the capacitor is located in the middle of the interior of the compensation cabinet body, a control switch is connected to the top of the capacitor, and a primary wiring terminal is installed above the control switch.

[0005] Preferably, the SVG module adopts RS485 or Ethernet communication mode, and the RS485 interface can support MODBUS communication protocol, power CDT communication protocol, Ethernet communication protocol is IEC / 104, and the rated frequency of the SVG module is 50Hz, and its response speed is no more than 5ms when it is 15Mvar and below, and no more than 10ms when it is above 15Mvar.

[0006] Preferably, a display screen is provided on the front outer surface of the compensation cabinet body, and the display screen is connected to the controller, and the display screen is provided with real-time power parameters, real-time curves and historical curves, historical event records, operation data records, fault recordings, reactive step recordings, voltage step recordings, online power monitoring functions, chain device unit status monitoring, software version and HMI storage space query items.

[0007] Preferably, the inverter power unit No. 1 and the inverter power unit No. 2 use advanced fully-controlled device IGBT chips, whose switching frequency is not less than 500H, and the withstand voltage of the IGBT chip is 1700V.

[0008] Preferably, the compensation cabinet body is in the shape of a cuboid, with a length of 2300 mm, a height of 2405 mm and a width of 1400 mm.

[0009] Preferably, a secondary terminal is installed at the lower end of the inner part of the compensation cabinet body and below the SVG module. Beneficial Effects

[0010] 1. The utility model discloses an SVG dynamic compensation cabinet for photovoltaic power generation. When the system power factor decreases due to changes in light intensity and load fluctuations, the SVG dynamic reactive power compensator can monitor the power factor of the power grid in real time and provide accurate reactive power compensation according to demand to adjust the phase difference between current and voltage, so that the SVG dynamic reactive power compensator can help the photovoltaic power generation system maintain a higher power factor, thereby improving the power generation efficiency.

[0011] 2. The utility model provides an SVG dynamic compensation cabinet for photovoltaics. When a large-scale photovoltaic power generation system is connected, problems such as voltage fluctuation and grid voltage imbalance may occur. By installing an SVG dynamic reactive power compensator, it can respond quickly when a grid failure or voltage fluctuation occurs. It balances the voltage and current of the grid by adjusting the output of reactive power, thereby maintaining the stable operation of the grid.

[0012] 3. The utility model is a SVG dynamic compensation cabinet for photovoltaics. When the photovoltaic power generation system becomes intermittent and unstable, resulting in a decrease in power quality, voltage harmonics will increase and voltage flicker will occur. The installed SVG dynamic reactive power compensator can monitor and control the voltage waveform of the power grid in real time, thereby effectively suppressing voltage harmonics and reducing voltage flicker, improving power quality, and thus improving power supply stability. BRIEF DESCRIPTION OF THE DRAWINGS

[0013] Other features, objects and advantages of the present application will become more apparent by reading the detailed description of non-limiting embodiments made with reference to the following drawings:

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

[0015] Figure 2 It is a side view of the utility model;

[0016] Figure 3 For the utility model

[0017] Figure 4 This is an installation diagram of the utility model.

[0018] In the figure: 1. High-voltage load switch; 2. Operation control box; 3. Vacuum contactor; 4. SVG module; 5. No. 1 inverter power unit; 6. No. 2 inverter power unit; 7. Centrifugal fan; 8. Control switch; 9. Capacitor; 10. Primary wiring terminal; 11. Secondary wiring terminal; 12. Compensation cabinet body. DETAILED DESCRIPTION

[0019] The present application is further described in detail below in conjunction with the accompanying drawings and embodiments. It is to be understood that the specific embodiments described herein are only used to explain the relevant utility model, rather than to limit the utility model. It is also necessary to explain that, for ease of description, only the parts related to the utility model are shown in the accompanying drawings.

[0020] The accompanying drawings in the embodiments of the present invention: different types of section lines in the drawings are not marked according to national standards, nor do they impose any requirements on the materials of the components. Instead, they are used to distinguish the cross-sectional views of the components in the drawings.

[0021] See also Figure 1-4A SVG dynamic compensation cabinet for photovoltaics includes a compensation cabinet body 12 and a capacitor 9. An operation control box 2 is installed inside the compensation cabinet body 12, and a high-voltage load switch 1 is arranged above the operation control box 2. A vacuum contactor 3 is installed below the operation control box 2, and an SVG module 4 is installed below the vacuum contactor 3 and at the lower left side of the compensation cabinet body 12. A No. 1 inverter power unit 5 and a No. 2 inverter power unit 6 are arranged side by side on the right side of the operation control box 2. A centrifugal fan 7 is installed at one end of the top of the compensation cabinet body 12, and one end of the centrifugal fan 7 is connected to the air duct. The capacitor 9 is located in the middle of the compensation cabinet body 12. A control switch 8 is connected to the top of the capacitor 9, and a primary wiring terminal 10 is installed above the control switch 8.

[0022] Among them, the SVG module 4 adopts RS485 or Ethernet communication mode, and the RS485 interface can support MODBUS communication protocol, power CDT communication protocol, Ethernet communication protocol is IEC / 104, and the rated frequency of the SVG module 4 is 50Hz, and its response speed is no more than 5ms when it is 15Mvar and below, and no more than 10ms when it is above 15Mvar.

[0023] Among them, a display screen is arranged on the front outer surface of the compensation cabinet body 12, and the display screen is connected to the controller. The display screen is provided with real-time power parameters, real-time curves and historical curves, historical event records, operation data records, fault recordings, reactive step recordings, voltage step recordings, online power monitoring functions, chain device unit status monitoring, software version and HMI storage space query items.

[0024] Among them, the No. 1 inverter power unit 5 and the No. 2 inverter power unit 6 use advanced fully-controlled device IGBT chips, whose switching frequency is not less than 500H, and the withstand voltage of the IGBT chip is 1700V.

[0025] The compensation cabinet body 12 is in the shape of a cuboid, with a length of 2300 mm, a height of 2405 mm, and a width of 1400 mm.

[0026] A secondary wiring terminal 11 is installed at the lower end of the compensation cabinet body 12 and below the SVG module 4 .

[0027] It should be noted that a photovoltaic SVG dynamic compensation cabinet is mainly composed of an operation control box 2, an SVG module 4, a first inverter power unit 5, a second inverter power unit 6, a centrifugal fan 7, a control switch 8, and a terminal block. The operation control box 2 is composed of a main control box and a display screen. The main control box is composed of various functional boards. It adopts a fully digital controller and a control core composed of DSP+FPGA. It gives full play to the super computing power of DSP and the excellent data processing ability of FPGA, calculates the reactive power required by the power grid in real time, and dynamically tracks and compensates, achieving accurate calculation, high-speed response, and compensation effects; and the display screen interface is a real-time display of the system operation status and data, query and set system operation parameters and whole machine logic control functions, with simple and convenient operation, friendly interface, and a human-computer interaction window; the basic function of the operation control box 2 is to use a complete set of device control system to realize pulse generation and distribution functions according to the changes in system voltage and reactive power, and automatically adjust the reactive output of the device; the complete set of devices has a parameter setting function for the duty officer, and all settings are not affected by power outages and interference signals.

[0028] The core of SVG module 4 is a chain inverter based on IGBT devices. Its power module adopts N+1 or N+2 redundant operation structure. The module control adopts large-scale FPGA chip carrier phase shift multi-level space vector PWM control strategy. It has the effects of simple circuit and strong anti-interference ability. Due to the use of self-excitation starting technology, the impact current is small when the device is put into use. The module panel of SVG module 4 has 4 electrical terminals and 2 optical fiber terminals. The wiring is simple and there are also several status and fault indicator lights for easy maintenance and repair.

[0029] Inverter power unit No. 1 5 and inverter power unit No. 2 6 are chain inverters, in which each phase is composed of multiple power module outputs in series, the main circuit adopts chain, star or triangle connection, each phase is composed of several commutation chain modules, and the commutation element IGBT chip should be an original imported product with a withstand voltage of 1700V.

[0030] When installing the centrifugal fan 7, the air duct shell needs to be extended to the outdoors to form a ventilation cycle between indoors and outdoors. A wire mesh must be installed at the air duct outlet to prevent small animals from entering the air duct. After the air duct is installed, the gap between the wall and the air duct should be sealed with sealing materials to prevent rainwater from entering the SVG body along the air duct. The air filter on the SVG device needs to be cleaned regularly to prevent dust from clogging the filter and affecting the air inlet. If there is an air inlet below the air outlet, a wind shield needs to be installed below the air duct outlet to prevent the hot air from being sucked into the air inlet below.

[0031] The switching frequency of the control switch 8 is not less than 500Hz. The selection of the main circuit components of the device should leave sufficient voltage and current margins, and the components should have good dv / dt and di / dt characteristics.

[0032] During installation, the SVG dynamic compensation cabinet comes with a channel steel base, which is welded to the buried channel steel. The embedded channel steel should be 5mm higher than the foundation plane to ensure reliable grounding of the cabinet. After the equipment is installed, sufficient space should be left in front, behind, left and right. The front distance should be greater than or equal to 1.5 meters, and the distance in the back is 1.0 meters; the distance on the left and right should be greater than or equal to 1.0 meters, and the distance from the cabinet to the roof should not be less than 1.5 meters. In order to ensure the isolation of various connecting cables, it is recommended to install angle iron brackets in the cable trench, angle iron specifications and bracket spacing. The cabinet threading holes and pipe holes should be sealed with fireproof mud after the cables and pipes are installed. The maximum humidity of the on-site installation environment is less than 95% all year round, and the average humidity is less than 90%. If it does not meet the requirements, air conditioning or air-water cooling should be used for heat dissipation. For sites with corrosive gases and conductive dust, air conditioning or air-water cooling must be used for heat dissipation.

[0033] It should be noted that, in the absence of conflict, the embodiments and features in the embodiments of the present application can be combined with each other. The present application will be described in detail below with reference to the accompanying drawings and in combination with the embodiments.

[0034] The above description is only a preferred embodiment of the present application and an explanation of the technical principles used. Those skilled in the art should understand that the scope of the utility model involved in the present application is not limited to the technical solution formed by a specific combination of the above technical features, but should also cover other technical solutions formed by any combination of the above technical features or their equivalent features without departing from the concept of the utility model. For example, the above features are replaced with the technical features with similar functions disclosed in the present application (but not limited to) by each other to form a technical solution.

Claims

1. A SVG dynamic compensation cabinet for photovoltaics, comprising a compensation cabinet body (12) and a capacitor (9), characterized in that: An operation control box (2) is installed inside the compensation cabinet body (12), and a high-voltage load switch (1) is arranged above the operation control box (2). A vacuum contactor (3) is installed below the operation control box (2), and an SVG module (4) is installed below the vacuum contactor (3) and at the lower left side of the compensation cabinet body (12). A first inverter power unit (5) and a second inverter power unit (6) are arranged side by side on the right side of the operation control box (2). A centrifugal fan (7) is installed at one end of the top of the compensation cabinet body (12), and one end of the centrifugal fan (7) is connected to an air duct. The capacitor (9) is located in the middle of the compensation cabinet body (12). A control switch (8) is connected to the top of the capacitor (9), and a primary wiring terminal (10) is installed above the control switch (8).

2. The SVG dynamic compensation cabinet for photovoltaic use according to claim 1, characterized in that: The SVG module (4) adopts RS485 or Ethernet communication mode, and the RS485 interface can support MODBUS communication protocol, power CDT communication protocol, and Ethernet communication protocol is IEC / 104. The rated frequency of the SVG module (4) is 50 Hz, and its response speed is not more than 5 ms when it is 15 Mvar or less, and not more than 10 ms when it is more than 15 Mvar.

3. The SVG dynamic compensation cabinet for photovoltaic use according to claim 1, characterized in that: A display screen is provided on the front outer surface of the compensation cabinet body (12), and the display screen is connected to the controller, and the display screen is provided with real-time electric quantity parameters, real-time curves and historical curves, historical event records, operation data records, fault recording, reactive power step recording, voltage step recording, online electric energy monitoring function, chain device unit status monitoring, software version and HMI storage space query items.

4. The SVG dynamic compensation cabinet for photovoltaic use according to claim 1, characterized in that: The first inverter power unit (5) and the second inverter power unit (6) use advanced fully-controlled device IGBT chips, the switching frequency of which is not less than 500H, and the withstand voltage of the IGBT chip is 1700V.

5. The SVG dynamic compensation cabinet for photovoltaic use according to claim 1, characterized in that: The compensation cabinet body (12) is in the shape of a rectangular parallelepiped, with a length of 2300 mm, a height of 2405 mm and a width of 1400 mm.

6. The SVG dynamic compensation cabinet for photovoltaic use according to claim 1, characterized in that: A secondary wiring terminal (11) is installed at the lower end of the interior of the compensation cabinet body (12) and below the SVG module (4).

Images