CN218958879U

CN218958879U - Photovoltaic grid-connected circuit structure

Info

Publication number: CN218958879U
Application number: CN202222721385.3U
Authority: CN
Inventors: 瞿世鹏; 徐臣; 王风雷; 张乐斌; 李一琨; 肖宝辉; 郑勇; 胡海军; 司小雷; 解胜权; 李英林
Original assignee: State Grid Comprehensive Energy Service Group Co ltd
Current assignee: State Grid Comprehensive Energy Service Group Co ltd
Priority date: 2022-10-14
Filing date: 2022-10-14
Publication date: 2023-05-02
Anticipated expiration: 2032-10-14

Abstract

The application relates to a photovoltaic grid-connected circuit structure, include: branch box and DC inverter. The direct current side of the direct current inverter is electrically connected with a plurality of photovoltaic group strings in the photovoltaic square matrix, and a branch box is electrically connected between the photovoltaic square matrix and the direct current inverter; each branch in the branch box is connected with a direct current fuse, a line current transformer and a line temperature sensor in series; the direct current fuse is electrically connected with the photovoltaic group string; the branch box is also provided with a box body temperature sensor, a communication unit and a busbar; the line current transformer, the line temperature sensor and the box body temperature sensor are all electrically connected with the communication unit. According to the photovoltaic grid-connected circuit structure, the direct-current inverter can be protected under the condition that the components are over-current, the current and the temperature of each loop can be monitored in real time, and feedback is timely carried out when faults occur, so that harm to personnel and equipment in the fault state is avoided.

Description

Photovoltaic grid-connected circuit structure

Technical Field

The application relates to the field of branch boxes, in particular to a photovoltaic grid-connected circuit structure.

Background

When the photovoltaic module is connected with the serial direct current inverter, the bypass diode is generally connected with each module in parallel to realize protection. When the battery assembly works normally, the bypass diode is reversely cut off, and no effect is generated on the circuit; if an abnormally operating battery piece exists in the battery self-construction parallel to the bypass diode, the reverse bias voltage is higher than the minimum voltage of the battery piece, and the bypass diode is conducted at the moment to short-circuit the abnormally operating battery piece, so that the output of the battery end is protected.

However, the over-current in the photovoltaic array comes from the ground fault in the component connecting line or the fault current of the internal component, the junction box or the component lead due to the short circuit, but the conventional diode cannot effectively meet the over-current protection requirement, and when the diode is conducted, the system cannot timely feed back the fault position and state.

In the prior art, the series inverter system is generally not provided with an overcurrent protection electric appliance at the access position of the inverter due to the limitation of a connection mode, the space of inverter equipment and the like, so that overload, ground fault, short circuit and arc fault which are difficult to monitor and protect caused by component side faults are difficult to cut off in time and feed back the system. Therefore, it is necessary to provide a dc side branch box integrating protection and monitoring to solve the above problems.

Disclosure of Invention

In view of this, the application provides a photovoltaic grid-connected circuit structure, can protect the dc-to-ac converter under the condition of subassembly overcurrent, can also monitor each return circuit electric current, temperature in real time, in time feed back when breaking down to avoid producing harm to personnel and equipment under the fault condition.

According to an aspect of the present application, there is provided a photovoltaic grid-connected circuit structure, including: branch box and DC inverter.

The direct current side of the direct current inverter is electrically connected with a plurality of photovoltaic group strings in a photovoltaic matrix, and the branch box is electrically connected between the photovoltaic matrix and the direct current inverter.

And each branch of the branch box is connected with a direct current fuse, a line current transformer and a line temperature sensor in series.

The direct current fuse is electrically connected with the photovoltaic group string.

And a box body temperature sensor, a communication unit and a bus are also arranged in the branch box.

The line current transformer, the line temperature sensor and the box body temperature sensor are all electrically connected with the communication unit.

In one possible implementation, the communication unit, the line current transformer, the line temperature sensor and the tank temperature sensor are connected by a communication cable.

In one possible implementation, the line current transformer is directly sleeved on the outgoing line of each plastic shell switch; the line temperature sensor is arranged inside the branch box.

In one possible implementation, the communication unit transmits to the monitoring host via 485 line using the robbus protocol.

In a possible implementation manner, the communication unit is further electrically connected with a power module, and an SPD may be optionally installed between the communication unit and the power module.

In one possible implementation manner, the photovoltaic array is formed by connecting a plurality of photovoltaic groups in series-parallel bypass diodes in series.

The beneficial effects of this application: according to another aspect of the application, a photovoltaic grid-connected circuit structure is provided, through setting up direct current fuses at the inside string circuit inlet end of group that is to cut in of branch box, each return circuit sets up current transformer and temperature sensor and communication unit, branch circuit monitor terminal and communication unit power are concentrated by monitoring system host computer and supply power, branch circuit current transformer directly overlaps on the play line of each plastic case switch, temperature sensor sets up in the box inside, the electrical quantity that branch circuit monitor terminal gathered utilizes MODBUS protocol transmission to communication unit through 485 lines, according to the photovoltaic grid-connected circuit structure of this application can protect direct current inverter under the subassembly overcurrent condition, can also each return circuit current of real-time supervision, temperature, timely feedback when breaking down, in order to avoid producing harm to personnel and equipment under the fault state.

Other features and aspects of the present application will become apparent from the following detailed description of exemplary embodiments, which proceeds with reference to the accompanying drawings.

Drawings

The accompanying drawings, which are incorporated in and constitute a part of this specification, illustrate exemplary embodiments, features and aspects of the present application and together with the description, serve to explain the principles of the present application.

FIG. 1 shows an overall circuit diagram of a photovoltaic grid-tie circuit architecture of an embodiment of the present application;

fig. 2 shows a schematic structural diagram of a photovoltaic grid-connected circuit structure according to an embodiment of the present application.

Detailed Description

Various exemplary embodiments, features and aspects of the present application will be described in detail below with reference to the accompanying drawings. In the drawings, like reference numbers indicate identical or functionally similar elements. Although various aspects of the embodiments are illustrated in the accompanying drawings, the drawings are not necessarily drawn to scale unless specifically indicated.

It should be understood, however, that the terms "center," "longitudinal," "transverse," "length," "width," "upper," "lower," "front," "rear," "left," "right," "vertical," "horizontal," "top," "bottom," "inner," "outer," "clockwise," "counter-clockwise," "axial," "radial," "circumferential," and the like indicate or are based on the orientation or positional relationship shown in the drawings, and are merely for convenience of description or to simplify the description, and do not indicate or imply that the devices or elements referred to must have a particular orientation, be configured and operated in a particular orientation, and therefore should not be construed as limiting the present application.

Furthermore, the terms "first," "second," and the like, are used for descriptive purposes only and are not to be construed as indicating or implying a relative importance or implicitly indicating the number of technical features indicated. Thus, a feature defining "a first" or "a second" may explicitly or implicitly include one or more such feature. In the description of the present application, the meaning of "a plurality" is two or more, unless explicitly defined otherwise.

The word "exemplary" is used herein to mean "serving as an example, embodiment, or illustration. Any embodiment described herein as "exemplary" is not necessarily to be construed as preferred or advantageous over other embodiments.

In addition, numerous specific details are set forth in the following detailed description in order to provide a better understanding of the present application. It will be understood by those skilled in the art that the present application may be practiced without some of these specific details. In some instances, methods, means, elements, and circuits have not been described in detail as not to unnecessarily obscure the present application.

Fig. 1 shows an overall circuit diagram of a photovoltaic grid-tie circuit structure according to an embodiment of the present application. As shown in fig. 1 and 2, the photovoltaic grid-connected circuit structure includes: a branch box 120 and a dc-inverter 130.

The dc side of the dc-dc converter 130 is electrically connected to a plurality of photovoltaic strings 111 in the photovoltaic array 110, and a branch box 120 is electrically connected between the photovoltaic array 110 and the dc-dc converter 130.

Each branch of the branch box 120 is connected with a direct current fuse 121, a line current transformer 123 and a line temperature sensor 124 in series.

The direct current fuse 121 is electrically connected with the photovoltaic string 111; when the component is in an overcurrent condition, the direct current fuse 121 can fuse the solution, so that the circuit is broken, and the protection of equipment and personnel is realized.

Also provided in the branch box 120 are a box temperature sensor 122, a communication unit 126, and a bus 125.

The line current transformer 123, the line temperature sensor 124 and the box temperature sensor 122 are all electrically connected with the communication unit 126; the communication unit 126 may receive signals from the line current transformer 123, the line temperature sensor 124 and the tank temperature sensor 122, detect the current and temperature of each loop in real time, and timely feed back the system status to the monitoring host when a fault occurs.

In one possible implementation, the communication unit 126, the line current transformer 124, the line temperature sensor 124, and the tank temperature sensor 122 are connected by a communication cable 127.

In one possible implementation, the line current transformer 124 is directly sleeved on the outgoing line of each plastic shell switch; the line temperature sensor 124 is disposed inside the junction box 120.

In one possible implementation, the communication unit 126 transmits to the monitoring host via 485 line using the robbus protocol.

In one possible implementation, the communication unit 126 is also electrically connected to a power module 140, and an SPD128 may also be optionally installed between the communication unit 126 and the power module 140.

In one possible implementation, the photovoltaic array 110 is formed by connecting a plurality of photovoltaic strings 111 in parallel with bypass diodes 112 and then connecting the bypass diodes in series with each other.

Therefore, the direct-current fuse is arranged in the branch box to serve as an overcurrent protection device, the direct-current inverter is protected under the condition that the component is overcurrent, the electric fire monitoring system is additionally arranged, the current and the temperature of each loop are monitored in real time, and the system state is timely fed back to the monitoring system host when the fault occurs, so that harm to personnel and equipment in the fault state is avoided.

The embodiments of the present application have been described above, the foregoing description is exemplary, not exhaustive, and not limited to the embodiments disclosed. Many modifications and variations will be apparent to those of ordinary skill in the art without departing from the scope and spirit of the various embodiments described. The terminology used herein was chosen in order to best explain the principles of the embodiments, the practical application, or the improvement of technology in the marketplace, or to enable others of ordinary skill in the art to understand the embodiments disclosed herein.

Claims

1. A photovoltaic grid-tie circuit structure, comprising: a branch box and a DC inverter;

the direct current side of the direct current inverter is electrically connected with a plurality of photovoltaic group strings in a photovoltaic matrix, and the branch box is electrically connected between the photovoltaic matrix and the direct current inverter;

each branch of the branch box is connected with a direct current fuse, a line current transformer and a line temperature sensor in series;

the direct current fuse is electrically connected with the photovoltaic group string;

the branch box is also provided with a box body temperature sensor, a communication unit and a bus;

2. The photovoltaic grid-tie circuit architecture of claim 1, wherein the communication unit, the line current transformer, the line temperature sensor and the tank temperature sensor are connected by a communication cable.

3. The photovoltaic grid-connected circuit structure according to claim 1, wherein the line current transformer is directly sleeved on the outgoing line of each plastic shell switch; the line temperature sensor is arranged inside the branch box.

4. The photovoltaic grid-tie circuit architecture of claim 1, wherein the communication unit transmits to the monitoring host via 485 line using robbus protocol.

5. The photovoltaic grid-connected circuit structure according to claim 1, wherein the communication unit is further electrically connected to a power module, and an SPD is optionally installed between the communication unit and the power module.

6. The photovoltaic grid-connected circuit structure according to claim 1, wherein the photovoltaic square matrix is formed by connecting a plurality of photovoltaic groups of series-parallel bypass diodes in series.