Distributed photovoltaic grid-connected intelligent switch device and system

Abstract

The utility model discloses a distributed photovoltaic grid-connected intelligent switch device and system, the intelligent switch device is arranged between an inverter and a power grid of the distributed photovoltaic grid-connected system, and the intelligent switch device comprises a control mainboard fixedly connected in a first housing and a reclosing mechanism in a second housing; through the processor, the measuring chip, the precise mutual inductor and the current protection mechanism which are arranged in the control main board and through the combination of the reclosing mechanism, the purpose of rapid grid connection is achieved, and the problem that grid connection time is long after an existing distributed photovoltaic system breaks down and is off-grid is solved.

Description

TECHNICAL FIELD

[0001] The utility model relates to photovoltaic grid switch technical field, concretely is a kind of distributed photovoltaic grid intelligent switch device and distributed photovoltaic grid intelligent switch system. BACKGROUND

[0002] Photovoltaic grid switch needs to have loss of voltage tripping and check voltage closing function, simultaneously also needs to have certain protective measure, according to different region to improve different standard, but existing photovoltaic grid switch, after the distributed photovoltaic fault off-grid, need to wait for professional repair personnel to find fault point after processing, especially since 99% above fault is instantaneous current fault, it can be automatically eliminated within the scheduled time, in this case, wait for professional repair personnel to know fault point after processing, greatly extend the time from fault occurrence to re-grid, the time-consuming process is longer, seriously affect economic benefit.

[0003] For example, Chinese patent application No. CN202221338951.6 discloses a distributed photovoltaic power generation grid-connected system, which includes a photovoltaic panel array configured to convert light energy into electrical energy; a voltage disturbance circuit in communication with the photovoltaic panel array, the voltage disturbance circuit being configured to output a disturbance voltage; an inverter in communication with the voltage disturbance circuit to receive the disturbance voltage output by the voltage disturbance circuit; and a grid-connected switch in communication with the inverter and the power grid, the grid-connected switch being configured to disconnect the circuit between the inverter and the power grid when the voltage output by the inverter exceeds an island voltage threshold.

[0004] However, in actual use, when the device fails, although the grid-connected switch can disconnect the circuit between the inverter and the power grid when the voltage output by the inverter exceeds the island voltage threshold, i.e., when the island phenomenon occurs, the photovoltaic panel array can be disconnected from the power grid, thereby effectively eliminating the island phenomenon in the distributed photovoltaic power generation grid-connected system. However, the elimination of the fault still requires professional repair personnel to handle on-site, and cannot solve the problem of long time from off-grid to grid-connected.

[0005] Therefore, there is an urgent need for a distributed photovoltaic grid intelligent switch device and system that can realize grid-connected after off-grid, in order to solve the problem mentioned above. Utility model content

[0006] The utility model aims at providing a distributed photovoltaic grid intelligent switch device and system to solve the technical problem of long time from off-grid to grid-connected after the distributed photovoltaic fault off-grid, which requires waiting for professional repair personnel to handle on-site.

[0007] To achieve the above-mentioned objectives, an embodiment of the present application provides, on the one hand, a distributed photovoltaic grid-connected intelligent switching device, which is arranged between the inverter of the distributed photovoltaic grid-connected system and the power grid, and includes a first shell, a second shell used in conjunction with the first shell, and a control mainboard, and the control mainboard is fixedly connected in the first shell; the control mainboard is provided with a processor, a measuring chip, a precision mutual inductor and a current protection mechanism, and the processor is circuit-associated with the measuring chip, and the measuring chip is circuit-associated with the precision mutual inductor, and the precision mutual inductor is circuit-connected in series with the current protection mechanism; a reclosing mechanism is provided inside the second shell, the reclosing mechanism is connected to the control mainboard, and the reclosing mechanism is circuit-connected in parallel with the circuit protection mechanism.

[0008] Furthermore, the precision transformer includes a precision voltage transformer and a precision current transformer, and the precision voltage transformer and the precision current transformer can effectively sense and control the voltage and current of the mainboard during operation.

[0009] Furthermore, the current protection mechanism includes a three-phase AC / DC power supply group and a current protection circuit.

[0010] Furthermore, the current protection circuit is associated with the reclosing mechanism circuit of the reclosing mechanism.

[0011] Furthermore, the reclosing mechanism includes an induction motor, a worm is provided at the bottom of the induction motor, a first turbine is provided in the middle of the second housing, the induction motor is meshedly connected to the first turbine via the worm, and the left end of the first turbine is meshedly connected to the second turbine;

[0012] A fixed rotating shaft is provided on the top of the second shell, the right end of the fixed rotating shaft is connected to the driving shaft, a switch piece is fixedly connected to the outside of the driving shaft, and a turbine piece is provided at the bottom of the fixed rotating shaft, which is engaged with the top of the second turbine.

[0013] Furthermore, the drive shaft is provided with three groups, and the drive shaft is rotationally connected with the inside of the first shell, and the induction motor is a permanent magnet DC motor. The rear end of the induction motor is provided with a power interface and a signal interface, and the induction motor is inductively connected to the control main board through the signal interface.

[0014] Furthermore, the drive shaft passes through the top of the control main board.

[0015] Furthermore, the control main board is provided with a switch action output information interface, a switch reset information interface and a wireless Internet of Things interface, and the switch action output information interface, the switch reset information interface and the wireless Internet of Things interface are electrically connected to the signal interface of the induction motor through an induction connection line.

[0016] Another aspect of the present application provides a distributed photovoltaic grid-connected intelligent switch system, comprising a photovoltaic assembly, an inverter and a power grid, and further comprising the distributed photovoltaic grid-connected intelligent switch device of any one of the above embodiments arranged between the inverter and the power grid.

[0017] Compared with the prior art, the present application has the following beneficial effects:

[0018] The present application provides a distributed photovoltaic grid-connected intelligent switch device to achieve the technical effect of timely re-grid after distributed photovoltaic fault off-grid.

[0019] Specifically, through the processor, the measurement chip, the precision mutual inductor and the current protection mechanism arranged on the control mainboard in the first shell, and the reclosing mechanism in the second shell, when the distributed photovoltaic system fails abnormally, the processor, the measurement chip and the precision mutual inductor on the control mainboard collect the abnormal signal of the photovoltaic circuit and transmit it to the current protection mechanism. The current protection mechanism will disconnect the circuit between the inverter and the power grid according to the fault reason. At this time, the reclosing mechanism connected with the processor of the control mainboard receives the disconnection signal and performs automatic reclosing operation within a preset time, so that the circuit between the inverter and the power grid is connected, the power supply is restored, and the technical effect of fast grid connection is achieved, greatly improving the economic benefit.

[0020] Further, the switching action output information interface, the switching reset information interface and the wireless Internet of Things interface are electrically connected with the signal interface of the induction motor of the reclosing mechanism, which ensures the stability of the signal transmission between the control mainboard and the reclosing mechanism, thereby increasing the timeliness and effectiveness of the distributed photovoltaic grid-connected system after off-grid.

[0021] Further, the current protection circuit is associated with the reclosing mechanism circuit of the reclosing mechanism, so that when the current protection circuit abnormally disconnects, the reclosing mechanism circuit is switched to realize the grid connection of the inverter and the power grid, achieving the technical effect of stable and fast grid connection. BRIEF DESCRIPTION OF DRAWINGS

[0022] Figure 1 is a front view of the reclosing mechanism arranged in the second shell in the embodiment of the present application;

[0023] Figure 2 is a front view of the control mainboard arranged in the first shell in the embodiment of the present application;

[0024] Figure 3 is a structural schematic view of the intelligent switch device in the embodiment of the present application;

[0025] Figure 4It is a structure schematic view of a control mainboard in the embodiment of the application.

[0026] Figure 5 It is a structure schematic view of a current protection mechanism in another embodiment of the application.

[0027] Figure 6 It is a structure schematic view of a distributed photovoltaic grid-connected intelligent switch system in another embodiment of the application.

[0028] In the figure: 1, first shell; 2, control mainboard; 201, processor; 202, measurement chip; 203, precision mutual inductor; 204, precision voltage mutual inductor; 205, precision current mutual inductor; 206, three-phase AC / DC power supply group; 207, current protection circuit; 208, switch action output information interface; 209, switch reset information interface; 210, wireless Internet of Things interface; 3, second shell; 4, induction motor; 5, power supply interface; 6, first turbine; 7, second turbine; 8, turbine blade; 9, fixed rotating shaft; 10, drive shaft; 11, switch blade. DETAILED DESCRIPTION

[0029] The technical solutions in the embodiments of the application will be clearly and completely described below with reference to the drawings in the embodiments of the application. Obviously, the described embodiments are only part of the embodiments of the application, rather than all the embodiments of the application.

[0030] Embodiment one

[0031] In order to solve the technical problem that it is difficult to solve the long time of distributed photovoltaic off-grid and re-grid in the prior art, the following scheme is disclosed in the embodiment:

[0032] Please refer to Figures 1-5 The embodiment provides a distributed photovoltaic grid-connected intelligent switch device, which is arranged between an inverter and a power grid of a distributed photovoltaic grid-connected system, plays a role of protection, off-grid and timely re-griding, and comprises a first shell 1, a second shell 3 and a control mainboard 2 arranged in the first shell 1. Figure 4 As shown in the figure, the control mainboard 2 is internally provided with a processor 201, a measurement chip 202, a precision mutual inductor 203 and a current protection mechanism, the processor 201 is in circuit association with the measurement chip 202, the measurement chip 202 is associated with the precision mutual inductor 203, and the precision mutual inductor 203 is associated with the current protection mechanism. Figure 1 Figure 4 ​As shown, the second housing 3 is internally provided with a reclosing mechanism connected with the control mainboard through a reclosing mechanism circuit, and the reclosing mechanism is in circuit parallel connection with the circuit protection mechanism. The precision mutual inductor 203 includes a precision voltage mutual inductor 204 and a precision current mutual inductor 205, which can effectively sense the voltage and current of the control mainboard during operation.

[0033] With the technical scheme of the embodiment, when the distributed photovoltaic device fails abnormally, the processor, the measurement chip, the precision mutual inductor on the control mainboard in the first housing collect the abnormal signal of the photovoltaic circuit and transmit it to the current protection mechanism. The current protection mechanism will disconnect the circuit between the inverter and the power grid according to the fault reason. At this time, the reclosing mechanism connected with the processor of the control mainboard receives the disconnection signal and performs automatic reclosing operation within a preset time, so that the circuit between the inverter and the power grid is connected, and the power supply is restored, thereby realizing the technical effect that the distributed photovoltaic device can be quickly and timely connected to the grid after abnormal fault off-grid, avoiding the trouble that the equipment fault must be handled by special personnel on site in the prior art, greatly improving the economic benefit, and also improving the satisfaction of power generation users.

[0034] It should be noted that the circuit of the current protection mechanism and the reclosing mechanism in the embodiment is in parallel connection. In the normal working condition of the distributed photovoltaic device, the reclosing mechanism is disconnected, and the circuit protection circuit normally operates to supply power and connect to the grid. When the distributed photovoltaic device appears general transient fault off-grid, within a preset time, generally about 1 minute, the transient fault will be automatically eliminated. The preferred method is to perform reclosing operation by using the accurate and high-accuracy verification no-voltage reclosing, and to restore timely power supply and grid connection. If the reclosing operation is performed again and disconnected, it will not be reclosed, which can be preliminarily determined as an extremely rare persistent fault. In this special case, special personnel need to be on site to handle and eliminate the fault before connecting to the grid.

[0035] Through repeated determination experiments, it is proved that the distributed photovoltaic grid-connected intelligent switch device provided by the embodiment can solve more than 99% of the distributed photovoltaic fault problems, and the success rate of transient fault is 100%, so that the technical effect that the distributed photovoltaic device can be timely connected to the grid after off-grid fault can be realized.

[0036] Embodiment two

[0037] On the basis of embodiment one, the embodiment is a preferred embodiment, like Figure 4 , 5As shown, the current protection mechanism of the embodiment includes a three-phase AC / DC power supply set 206 and a current protection circuit 207; the current protection circuit includes a residual current protection circuit, an instantaneous short-circuit protection circuit and a three-phase current imbalance protection circuit; wherein the residual current circuit induces a relatively small AC current from the leakage current through a zero sequence transformer, and the induced AC current is introduced into the related sampling circuit of the control mainboard. The three-phase imbalance current detection circuit is processed by the principle of zero crossing.

[0038] Specifically, the current protection mechanism of the embodiment has an overvoltage protection function. When the circuit monitors that the incoming voltage exceeds the industry standard value, overvoltage processing will be performed, the current protection mechanism is disconnected and powered off, and no longer works, thereby playing a protection role. The specific implementation method can adopt six 200K resistors, one 20K resistor for series connection and voltage division, then take the voltage at the end of the 20K resistor, perform AD conversion to convert the analog signal into a digital signal, and the processor judges and processes the converted digital signal. When the number exceeds the threshold value we set, the processor will send a command to make the protection mechanism disconnect, thereby playing a protection role. When the current of the three-phase power is unbalanced, the three-phase imbalance current protection circuit will generate a signal change, which will be transmitted to the processor and judged to make a disconnect action to achieve the protection effect.

[0039] When the current protection mechanism is disconnected, the processor transmits the disconnection signal to the reclosing mechanism, at which time the reclosing mechanism performs automatic reclosing operation to make the reclosing mechanism circuit connected to continue grid power supply, thereby achieving the effect of timely and rapid re-grid after off-grid.

[0040] Embodiment three

[0041] On the basis of embodiment one, the embodiment is a preferred embodiment, as shown in Figures 1-3 As shown, the second housing 3 is internally provided with a reclosing mechanism, and the reclosing mechanism is connected with the switch piece 11. The reclosing mechanism includes an induction motor 4, and the bottom of the induction motor 4 is provided with a worm, the middle of the second housing 3 is provided with a first turbine 6, the induction motor 4 is engaged with the first turbine 6 through the worm, and the left end of the first turbine 6 is engaged with a second turbine 7; the top of the second housing 3 is provided with a fixed rotating shaft 9, and the bottom of the fixed rotating shaft 9 is provided with a turbine blade 8, and the turbine blade 8 can be engaged with the top of the second turbine 7, the right end of the fixed rotating shaft 9 is connected with a drive shaft 10, the drive shaft 10 passes through the top of the control mainboard 2, and the outer side of the drive shaft 10 is fixedly connected with the switch piece 11.

[0042] The driving shaft 10 is provided with three groups, and the driving shaft 10 is rotatably connected with the first shell 1, and the induction motor 4 is a permanent magnet DC motor, the rear end of the induction motor 4 is provided with a power supply interface 5 and a signal interface, and the induction motor 4 is in circuit induction with the control mainboard 2, the control mainboard 2 is internally provided with a switch action output information interface 208, a switch reset information interface 209 and a wireless Internet of Things interface 210, the switch action output information interface 208, the switch reset information interface 209 and the wireless Internet of Things interface 210 are electrically connected with the signal interface of the induction motor through an induction connecting line, so that the control mainboard and the reclosing mechanism are electrically connected, the stability of signal transmission between the control mainboard and the reclosing mechanism is ensured, and the timeliness and effectiveness of the distributed photovoltaic grid-connected system after being reconnected to the grid after being disconnected from the grid are improved.

[0043] Embodiment four

[0044] The embodiment provides a distributed photovoltaic grid-connected intelligent switch system, as shown in the figure, the system comprises a photovoltaic assembly, an inverter and a power grid, and further comprises the distributed photovoltaic grid-connected intelligent switch device in any one of the above-mentioned embodiment one, embodiment two and embodiment three arranged between the inverter and the power grid. Figure 6

[0045] In summary, the distributed photovoltaic fault disconnection reclosing intelligent switch device is provided, and the technical effect that the distributed photovoltaic system can be reconnected to the grid in time after being disconnected from the grid is realized.

[0046] Specifically, the processor, the measurement chip, the precision mutual inductor and the current protection mechanism on the control mainboard in the first shell and the reclosing mechanism in the second shell are arranged, when the distributed photovoltaic system is abnormal due to faults, the processor, the measurement chip and the precision mutual inductor on the control mainboard collect abnormal signals of the photovoltaic circuit and transmit the abnormal signals to the current protection mechanism, the current protection mechanism disconnects the circuit between the inverter and the power grid according to the fault reason; at this time, the reclosing mechanism connected with the processor of the control mainboard receives the disconnection signal and performs automatic reclosing operation within a preset time, so that the circuit between the inverter and the power grid is connected, power supply is restored, and the technical effect of rapid grid connection is realized, and economic benefits are greatly improved.

[0047] Further, the switch action output information interface, the switch reset information interface and the wireless Internet of Things interface are electrically connected with the signal interface of the induction motor of the reclosing mechanism, the stability of signal transmission between the control mainboard and the reclosing mechanism is ensured, and the timeliness and effectiveness of the distributed photovoltaic grid-connected system after being reconnected to the grid after being disconnected from the grid are improved.

[0048] ​Further, by associating the current protection circuit with the reclosing mechanism circuit of the reclosing mechanism, when the current protection circuit abnormally disconnects, the reclosing mechanism circuit is switched to use to realize the grid connection of the inverter and the power grid, so as to achieve the technical effect of stable and rapid grid connection.

[0049] The contents not described in detail in the specification belong to the prior art known to those skilled in the art.

[0050] The above refers to the structural diagram of various embodiments of the present application. It should be noted that the distributed photovoltaic intelligent switch device and system of the present application includes a plurality of program modules in the above embodiments, each of which includes a plurality of individual software objects or components for realizing various functions. These software objects or components can be embodied in hardware by using interconnecting components such as wired or wireless lines.

[0051] Unless otherwise defined, the technical terms or scientific terms used in the embodiments of the present application should be understood as the usual meaning understood by those skilled in the art. The "first", "second" and similar words used in the embodiments of the present application do not represent any order, quantity or importance, but are only used to distinguish different components. "Include" or "contain" and similar words mean that the elements or objects before the word cover the elements or objects listed after the word and their equivalents, without excluding other elements or objects. "Connected" or "connected" and similar words are not limited to physical or mechanical connection, but can include electrical connection, whether direct or indirect. "Up", "down", "left", "right" and the like are only used to represent relative positional relationship, when the absolute position of the described object changes, the relative positional relationship may also change accordingly.

[0052] So far, the embodiments of the present application have been described in detail. In order to avoid obscuring the concept of the present application, the conventional means in the technical field to which the present application belongs are not described. Although the preferred embodiments of the present application have been described, the present application is not limited to the disclosed embodiments, but should be interpreted in the broadest sense within the scope of the appended claims.

Claims

1. A distributed photovoltaic grid-connected intelligent switch device, which is arranged between an inverter and a power grid of a distributed photovoltaic grid-connected system, comprising a first shell, a second shell used in cooperation with the first shell, and a control mainboard, characterized in that, The control mainboard is fixedly connected in the first shell; The control mainboard is provided with a processor, a measuring chip, a precision mutual inductor and a current protection mechanism, the processor is in circuit association with the measuring chip, the measuring chip is in circuit association with the precision mutual inductor, and the precision mutual inductor is in circuit series connection with the current protection mechanism; The second shell is internally provided with a reclosing mechanism, the reclosing mechanism is connected with the control mainboard, and the reclosing mechanism is in circuit parallel connection with the current protection mechanism.

2. The distributed photovoltaic grid-tie intelligent switch device of claim 1, wherein, The precision mutual inductor comprises a precision voltage mutual inductor and a precision current mutual inductor, and can effectively induct the voltage and current of the control mainboard during operation.

3. The distributed photovoltaic grid-tie intelligent switch device of claim 1, wherein, The current protection mechanism comprises a three-phase AC / DC power supply group and a current protection circuit.

4. The distributed PV grid-tie intelligent switch device of claim 3, wherein, The current protection circuit is in circuit association with the reclosing mechanism circuit of the reclosing mechanism.

5. The distributed photovoltaic grid-tie intelligent switch device of claim 1, wherein, The reclosing mechanism comprises an induction motor, the bottom of the induction motor is provided with a worm, the middle of the second shell is provided with a first turbine, the induction motor is meshed and connected with the first turbine through the worm, and the left end of the first turbine is meshed and connected with a second turbine; The top of the second shell is provided with a fixed rotating shaft, the right end of the fixed rotating shaft is connected with a driving shaft, the outer side of the driving shaft is fixedly connected with a switch piece, the bottom of the fixed rotating shaft is provided with a turbine piece, and the turbine piece is meshed with the top of the second turbine.

6. The distributed photovoltaic grid-tie intelligent switch device of claim 5, wherein, The driving shaft is provided with three groups, the driving shaft is in rotating connection with the inside of the first shell, the induction motor is a permanent magnet DC motor, the rear end of the induction motor is provided with a power supply interface and a signal interface, and the induction motor is inductive connected with the control mainboard through the signal interface.

7. The distributed photovoltaic grid-tie intelligent switch device of claim 5, wherein, The driving shaft penetrates through the top of the control mainboard.

8. The distributed PV grid-tie intelligent switch device of claim 6, wherein, The control mainboard is provided with a switch action output information interface, a switch reset information interface and a wireless Internet of Things interface, and the switch action output information interface, the switch reset information interface and the wireless Internet of Things interface are electrically connected with the signal interface of the induction motor through an inductive connecting line.

9. A distributed photovoltaic grid-tie intelligent switch system comprising a photovoltaic assembly, an inverter and a grid, characterized in that, The distributed photovoltaic grid-connected intelligent switch device of any one of claims 1-8 is arranged between an inverter and a power grid.

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