Photovoltaic low-voltage grid-connected switch cabinet

Abstract

The utility model relates to the technical field of photovoltaic switch equipment, in particular to a photovoltaic low-voltage grid-connected switch cabinet, which comprises a plurality of photovoltaic wire inlet units and wire inlet switches respectively connected onto the plurality of photovoltaic wire inlet units, and one side of each wire inlet switch is respectively connected with a transformer. The transformer is respectively connected with an alternating current grid-connected circuit and a direct current grid-connected circuit, and the alternating current grid-connected circuit and the direct current grid-connected circuit are arranged on the transformer in parallel; the alternating-current grid-connected circuit comprises an electromagnetic wire unit, a normally-open magnetic switch, an inverter and an alternating-current grid-connected outgoing line unit which are sequentially connected along a direction far away from the transformer; the direct current grid-connected circuit comprises a transformer which is sequentially connected with a normally-closed magnetic switch and a direct current grid-connected outgoing line unit in the direction away from the transformer. The photovoltaic low-voltage grid-connected switch cabinet provided by the utility model can prevent the electric energy of a photovoltaic power generation system from being too large, avoids waste of the electric energy, and is convenient for maintainers to maintain an alternating-current grid-connected circuit.

Description

Technical Field

[0001] The utility model relates to the technical field of photovoltaic switch equipment, in particular to a photovoltaic low-voltage grid-connected switch cabinet. Background Art

[0002] my country has abundant solar energy resources, with the average annual daily radiation in most areas reaching 4 kWh / m 2 .d and above, compared with other countries at the same latitude, it is superior to Europe and Japan, and therefore has favorable conditions for the extensive construction of photovoltaic power stations. However, from the perspective of photovoltaic development, ensuring the rationality of the design of low-voltage switch grid cabinets is to ensure their effective function and maximize safety. With the continuous advancement of distributed photovoltaic power generation technology, since photovoltaic panels for photovoltaic power generation need to occupy a large amount of illumination area, the distribution of low-voltage switch grid cabinets presents the characteristics of "dense points and decentralized". The photovoltaic power in a certain area is concentrated through the low-voltage switch grid cabinet, and the concentrated power is transmitted to the power grid using the grid-connected unit to meet the use requirements of photovoltaic energy.

[0003] For photovoltaic power generation systems, the island phenomenon caused by power failure on the grid side requires maintenance personnel to perform maintenance. However, at this time, the photovoltaic power generation system is still in the power generation state. Since the low-voltage switch grid cabinets are scattered in multiple regions, it is difficult for maintenance personnel to repair the low-voltage switch grid cabinets in the first time. Therefore, the photovoltaic power generation system that produces the island phenomenon needs to load a large amount of photovoltaic power. For the components in the photovoltaic power generation system, when the load power of the components is too large, it will cause impact damage to the load components in the power generation, affecting the normal use of the photovoltaic power generation system. To solve this problem, a remote master control switch or a grounding system is installed on the photovoltaic power generation system. That is, when the power of the photovoltaic power generation system is too large, the remote master control switch is controlled to close or the grounding system is used to export the excess power. In this way, although the load components in the invention can be avoided from being damaged, at the same time, the solar energy is also wasted. Therefore, it is a topic worthy of in-depth study to ensure the reasonable transmission of solar energy and ensure that the photovoltaic low-voltage grid-connected switch cabinet effectively plays the role of power transmission. Summary of the invention

[0004] In view of the deficiencies in the prior art, the utility model provides a photovoltaic low-voltage grid-connected switch cabinet that can prevent excessive electrical energy in the photovoltaic power generation system, avoid wasting electrical energy, and facilitate maintenance personnel to maintain the AC grid-connected circuit, thereby overcoming the defects in the prior art.

[0005] The technical solution adopted by the utility model is: a photovoltaic low-voltage grid-connected switch cabinet, comprising a plurality of photovoltaic incoming line units and incoming line switches respectively connected to the plurality of photovoltaic incoming line units, one side of the plurality of incoming line switches respectively connected to a transformer, an AC grid-connected circuit and a DC grid-connected circuit respectively connected to the transformer, and the AC grid-connected circuit and the DC grid-connected circuit are arranged in parallel on the transformer; the AC grid-connected circuit comprises an electromagnetic wire unit, a normally open magnetic switch, an inverter and an AC grid-connected outlet unit which are sequentially connected to the transformer in a direction away from the transformer; the DC grid-connected circuit comprises a normally closed magnetic switch and a DC grid-connected outlet unit which are sequentially connected to the transformer in a direction away from the transformer; the electromagnetic wire unit is located on the induction end of the normally open magnetic switch and the normally closed magnetic switch.

[0006] Preferably, one side of the electromagnetic wire unit has a reset circuit, and the reset circuit includes a button and a protective resistor, wherein two ends of the button are respectively connected to one end of the protective resistor and the output end of the electromagnetic wire unit, and the other end of the protective resistor is connected to the output end of the normally closed magnetic switch.

[0007] Preferably, a filter and an AC grid-connected switch are respectively provided between the inverter and the AC grid-connected output unit, and the inverter is sequentially connected to the filter and the AC grid-connected switch along a direction approaching the AC grid-connected output unit.

[0008] Preferably, a bulb and a grid-connected diode are respectively arranged between the normally closed magnetic switch and the DC grid-connected output unit, the grid-connected diode and the bulb are connected in parallel to one end of the normally closed magnetic switch, and the DC grid-connected output unit is connected to the normally closed magnetic switch through the grid-connected diode.

[0009] Preferably, an incoming line diode and a capacitor are provided between the transformer and the incoming line switch, and the incoming line switch is sequentially connected to the incoming line diode and the capacitor along a direction approaching the transformer.

[0010] Preferably, the number of the AC grid-connected circuits and the DC grid-connected circuits are no less than two, an AC grid-connected bus unit is provided on one side of the AC grid-connected circuit, and the AC grid-connected outgoing line units of several AC grid-connected circuits are all connected to the AC grid-connected bus unit, and a DC grid-connected bus unit is provided on one side of the DC grid-connected circuit, and the DC grid-connected outgoing line units of several DC grid-connected circuits are all connected to the DC grid-connected bus unit.

[0011] The beneficial effects of the utility model are as follows: firstly, the utility model adjusts the voltage generated by the photovoltaic power generation system through the provided transformer, so that the voltage of the collected electric energy meets the requirements of the power grid transmission, and divides two electric energy output modes through the provided AC grid-connected circuit and the DC grid-connected circuit, and with the help of the magnetism of the electromagnetic wire unit, when the AC grid-connected circuit loses power, a normally open magnetic switch and a normally closed magnetic switch are used to make a switching action, so that the electric energy generated by the photovoltaic can be switched and transmitted to the DC grid-connected circuit, so as to prevent the electric energy of the photovoltaic power generation system from being too large and to avoid wasting electric energy, and at the same time, the AC grid-connected circuit is disconnected so that maintenance personnel can maintain the AC grid-connected circuit.

[0012] Secondly, the utility model sets a reset circuit so that after the AC grid-connected circuit is repaired, the AC grid-connected circuit can be reset by pressing a button, so that when the electromagnetic wire unit is energized, the normally open magnetic switch is in a closed state, and the normally closed magnetic switch is in a disconnected state, so as to switch the AC grid-connected circuit to a power supply state, and at the same time the DC grid-connected circuit is in a disconnected state, thereby controlling the photovoltaic power generation to be transmitted to the AC grid-connected circuit; and the utility model sets a filter so that the frequency point of a specific frequency in the AC grid-connected circuit or frequencies other than the frequency point can be effectively filtered out, thereby obtaining a power supply of a specific frequency, so as to facilitate the output of electric energy through the AC grid, and through the set AC grid-connected switch, the AC grid-connected circuit can be switched to the DC grid-connected circuit manually or remotely, so as to meet the switching between the grid-connected circuit and the DC grid-connected circuit.

[0013] Thirdly, the utility model sets a light bulb so that when the DC grid-connected circuit is powered on, the light bulb will light up, so that personnel can understand the current transmission of photovoltaic power. At the same time, the grid-connected diode is set to prevent the power from flowing back into the DC grid-connected circuit, so as to improve the stability of power transmission. In addition, the utility model sets the incoming line diode and capacitor to tune, couple, filter, etc. the incoming line unit, so as to prevent the power from flowing back into the photovoltaic power generation system through the photovoltaic incoming line unit, so as to improve the stability of power transmission. BRIEF DESCRIPTION OF THE DRAWINGS

[0014] Figure 1 It is a circuit diagram of the utility model.

[0015] Figure 2 This is a connection circuit diagram of the photovoltaic incoming line unit and the AC grid-connected circuit and the DC grid-connected circuit in the utility model. DETAILED DESCRIPTION

[0016] like Figures 1 to 2As shown, a photovoltaic low-voltage grid-connected switch cabinet includes a plurality of photovoltaic incoming line units 1 and incoming line switches 2 respectively connected to the plurality of photovoltaic incoming line units 1, one side of the plurality of incoming line switches 2 is respectively connected to a transformer 3, an AC grid-connected circuit and a DC grid-connected circuit are respectively connected to the transformer 3, and the AC grid-connected circuit and the DC grid-connected circuit are arranged in parallel on the transformer 3; the AC grid-connected circuit includes an electromagnetic wire unit 4, a normally open magnetic switch 5, an inverter 6 and an AC grid-connected outlet unit 7 connected in sequence to the transformer 3 in a direction away from the transformer 3; the DC grid-connected circuit includes a normally closed magnetic switch 8 and a DC grid-connected outlet unit 9 connected in sequence to the transformer 3 in a direction away from the transformer 3; the electromagnetic wire unit 4 is located on the induction end of the normally open magnetic switch 5 and the normally closed magnetic switch 8. The photovoltaic incoming line unit 1 is connected to the photovoltaic power generation system so that the photovoltaic power generation electric energy can be transmitted to the photovoltaic incoming line unit 1. For this reason, when the AC grid-connected circuit loses power, the magnetism of the electromagnetic wire unit 4 disappears, and the normally open magnetic switch 5 returns to the normally open state, thereby cutting off the power to the AC grid-connected circuit, so that maintenance personnel can maintain the AC grid-connected circuit. At the same time, the normally closed magnetic switch 8 returns to the normally closed state, so that the photovoltaic power generation can be switched and transmitted to the DC grid-connected circuit to avoid wasting electric energy.

[0017] In this embodiment, the reset circuit on one side of the electromagnetic wire unit 4 includes a button 10 and a protective resistor 11. The two ends of the button 10 are respectively connected to one end of the protective resistor 11 and the output end of the electromagnetic wire unit 4, and the other end of the protective resistor 11 is connected to the output end of the normally closed magnetic switch 8. After the AC grid-connected circuit is repaired, the AC grid-connected circuit is reset by pressing the button 10; that is, the reset circuit is in the power-on state, and the electromagnetic wire unit 4 is controlled to be powered on, so that the normally open magnetic switch 5 is in the closed state and the normally closed magnetic switch 8 is in the open state under the magnetic attraction of the electromagnetic wire unit 4; for this reason, the AC grid-connected circuit is in the power supply state, and at the same time, the DC grid-connected circuit is in the open state, so as to control the power generated by photovoltaic to be transmitted to the AC grid-connected circuit.

[0018] Specifically, a filter 12 and an AC grid-connected switch 13 are respectively arranged between the inverter 6 and the AC grid-connected output unit 7. The inverter 6 is connected to the filter 12 and the AC grid-connected switch 13 in sequence along the direction close to the AC grid-connected output unit 7. The filter 12 is used to effectively filter out the frequency point of a specific frequency in the AC grid-connected circuit or the frequency other than the frequency point, thereby obtaining a power supply of a specific frequency to facilitate the output of electric energy through the AC grid; and the AC grid-connected switch is used to manually or remotely control the AC grid-connected circuit to switch to the DC grid-connected circuit to meet the switching between the grid-connected circuit and the DC grid-connected circuit.

[0019] In this embodiment, a light bulb 14 and a grid-connected diode 15 are respectively arranged between the normally closed magnetic switch 8 and the DC grid-connected output unit 9. The grid-connected diode 15 and the light bulb 14 are connected in parallel to one end of the normally closed magnetic switch 8. The DC grid-connected output unit 9 is connected to the normally closed magnetic switch 8 through the grid-connected diode 15, so that when the DC grid-connected circuit is energized, the light bulb 14 will light up to facilitate personnel to understand the current transmission status of photovoltaic power. At the same time, the grid-connected diode 15 is set to prevent electric energy from flowing back into the DC grid-connected circuit to improve the stability of power transmission.

[0020] It should be pointed out that an incoming line diode 16 and a capacitor 17 are arranged between the transformer 3 and the incoming line switch 2. The incoming line switch 2 is connected to the incoming line diode 16 and the capacitor 17 in sequence along the direction close to the transformer 3. The arranged capacitor plays the role of tuning, coupling, filtering, etc.; and the arranged incoming line diode 16 prevents electric energy from flowing back into the photovoltaic power generation system through the photovoltaic incoming line unit 1, so as to improve the stability of electric energy transmission.

[0021] In this embodiment, the number of the AC grid-connected circuits and the DC grid-connected circuits is no less than two, an AC grid-connected bus unit 18 is provided on one side of the AC grid-connected circuit, and the AC grid-connected line output units 7 of several AC grid-connected circuits are all connected to the AC grid-connected bus unit 18, and a DC grid-connected bus unit 19 is provided on one side of the DC grid-connected circuit, and the DC grid-connected line output units 9 of several DC grid-connected circuits are all connected to the DC grid-connected bus unit 19, thereby completing AC grid connection or DC grid connection, that is, transferring electric energy to the power grid.

[0022] The use of this product is as follows: Figures 1 to 2 As shown, first, after the assembly of this product is completed, the incoming switch 2 and the outgoing terminal of the photovoltaic power generation system are in the disconnected state, and the incoming switch 2 and the outgoing terminal of the photovoltaic power generation system are connected using the photovoltaic incoming unit (1); and the DC grid-connected bus unit (19) is connected to the DC grid, and the AC grid-connected bus unit (18) is connected to the AC grid. Then, the incoming switch 2 is turned on, and the outgoing terminal of the photovoltaic power generation system is controlled to be in the closed state, so that the light bulb 14 is energized and lit, so that the electric energy generated by the photovoltaic power generation system is transmitted to the DC grid; then, by pressing the button 10, the electromagnetic wire unit 4 is controlled to be energized, so that under the magnetic attraction of the electromagnetic wire unit 4, the normally open magnetic switch 5 is in the closed state, and the normally closed magnetic switch 8 is in the disconnected state, so that the AC grid-connected circuit is in the power supply state, and at the same time the DC grid-connected circuit is in the disconnected state, that is, the light bulb 14 loses power and goes out, so as to supply power to the AC grid.

[0023] Through this embodiment, the transformer 3 provided in this embodiment adjusts the voltage generated by the photovoltaic power generation system to facilitate the voltage of the collected electric energy to meet the requirements of the power grid transmission. Through the provided AC grid-connected circuit and DC grid-connected circuit, two electric energy output modes are divided. With the help of the magnetism of the electromagnetic wire unit 4, when the AC grid-connected circuit loses power, the normally open magnetic switch 5 and the normally closed magnetic switch 8 are used to make a switching action, so that the electric energy generated by the photovoltaic can be switched and transmitted to the DC grid-connected circuit, preventing the photovoltaic power generation system from having too much electric energy and avoiding wasting electric energy. At the same time, the AC grid-connected circuit is disconnected so that maintenance personnel can maintain the AC grid-connected circuit.

[0024] The embodiments described above are only preferred embodiments of the present invention and are not intended to limit the scope of implementation of the present invention. Therefore, any equivalent changes or modifications made based on the structures, features and principles described in the patent scope of the present invention should be included in the patent application scope of the present invention.

Claims

1. A photovoltaic low-voltage grid-connected switch cabinet, comprising a plurality of photovoltaic incoming line units (1) and incoming line switches (2) respectively connected to the plurality of photovoltaic incoming line units (1), characterized in that: One side of each of the plurality of incoming line switches (2) is respectively connected to a transformer (3), and an AC grid-connected circuit and a DC grid-connected circuit are respectively connected to the transformer (3), and the AC grid-connected circuit and the DC grid-connected circuit are arranged in parallel on the transformer (3); The AC grid-connected circuit comprises an electromagnetic wire unit (4), a normally open magnetic switch (5), an inverter (6), and an AC grid-connected outlet unit (7) which are sequentially connected to the transformer (3) in a direction away from the transformer (3); The DC grid-connected circuit comprises a transformer (3) connected in sequence to a normally closed magnetic switch (8) and a DC grid-connected outgoing line unit (9) in a direction away from the transformer (3); The electromagnetic wire unit (4) is located on the sensing ends of the normally open magnetic switch (5) and the normally closed magnetic switch (8).

2. The photovoltaic low-voltage grid-connected switch cabinet according to claim 1 is characterized in that: A reset circuit on one side of the electromagnetic wire unit (4), the reset circuit comprising a button (10) and a protective resistor (11), two ends of the button (10) being respectively connected to one end of the protective resistor (11) and an output end of the electromagnetic wire unit (4), and the other end of the protective resistor (11) being connected to the output end of the normally closed magnetic switch (8).

3. The photovoltaic low-voltage grid-connected switch cabinet according to claim 1 is characterized in that: A filter (12) and an AC grid-connected switch (13) are respectively arranged between the inverter (6) and the AC grid-connected output line unit (7), and the inverter (6) is connected to the filter (12) and the AC grid-connected switch (13) in sequence along a direction approaching the AC grid-connected output line unit (7).

4. The photovoltaic low-voltage grid-connected switch cabinet according to claim 1, characterized in that: A light bulb (14) and a grid-connected diode (15) are respectively arranged between the normally closed magnetic switch (8) and the DC grid-connected output line unit (9); the grid-connected diode (15) and the light bulb (14) are connected in parallel to one end of the normally closed magnetic switch (8); and the DC grid-connected output line unit (9) is connected to the normally closed magnetic switch (8) via the grid-connected diode (15).

5. The photovoltaic low-voltage grid-connected switch cabinet according to claim 1, characterized in that: An incoming line diode (16) and a capacitor (17) are provided between the transformer (3) and the incoming line switch (2), and the incoming line switch (2) is connected to the incoming line diode (16) and the capacitor (17) in sequence along a direction approaching the transformer (3).

6. The photovoltaic low-voltage grid-connected switch cabinet according to claim 1, characterized in that: The number of the AC grid-connected circuits and the DC grid-connected circuits is no less than two. An AC grid-connected bus unit (18) is provided on one side of the AC grid-connected circuit, and the AC grid-connected outgoing line units (7) of the plurality of AC grid-connected circuits are all connected to the AC grid-connected bus unit (18). A DC grid-connected bus unit (19) is provided on one side of the DC grid-connected circuit, and the DC grid-connected outgoing line units (9) of the plurality of DC grid-connected circuits are all connected to the DC grid-connected bus unit (19).

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