CN214337575U - Safe and energy-saving photovoltaic power distribution box system - Google Patents
Safe and energy-saving photovoltaic power distribution box system Download PDFInfo
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- CN214337575U CN214337575U CN202120576023.2U CN202120576023U CN214337575U CN 214337575 U CN214337575 U CN 214337575U CN 202120576023 U CN202120576023 U CN 202120576023U CN 214337575 U CN214337575 U CN 214337575U
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Abstract
The utility model discloses a safe and energy-saving photovoltaic distribution box system, which is applied between a power grid and an inverter and comprises a load switch, a sunshine time synchronization device, an active switching-off and switching-on device and a leakage current detection device, wherein the wire inlet end of the load switch is connected with the power grid end, and the wire outlet end of the load switch is connected with the active switching-off and switching-on device; the leakage current detection device is arranged at the wire outlet end of the active switching-on and switching-off device and is sleeved on the live wire and the zero wire of the active switching-on and switching-off device; the outlet end of the active switching-on/off device passes through the leakage current detection device and is connected with the inverter, and a lightning protection device is also arranged between the leakage current detection device and the inverter; the output of leakage current detection device is connected with main control unit, and the output signal of sunshine time contemporary dress also links to each other with main control unit, the utility model discloses can be according to sunshine condition, electric wire netting voltage condition, the divide-shut brake action of leakage current control initiative divide-shut brake device, the automatic control dc-to-ac converter breaks off with the electric wire netting, reduces the loss, extension dc-to-ac converter life-span.
Description
Technical Field
The utility model relates to a photovoltaic grid-connected power distribution box technical field especially relates to a safe and energy-conserving photovoltaic power distribution box system.
Background
The earth energy is increasingly exhausted, the population and the environment are increasingly stressed, and the development of renewable energy sources becomes a necessary choice for people. Photovoltaic power generation is taken as a main renewable energy source, and the application prospect of the photovoltaic power generation is widely accepted in the whole society. The storage cost of large-scale photovoltaic power generation is huge, so that the photovoltaic power generation needs to be connected with a power grid in a grid mode and is transmitted to other users through a public power grid. A special photovoltaic grid-connected distribution box belongs to one of main devices in the field of distributed power generation, and directly injects clean energy generated by a grid-connected inverter into a public power grid.
The importance of the position of the system as an interface system for connecting the photovoltaic grid-connected inverter with the power grid is self-evident. The current photovoltaic block terminal mainly has the problem in following several aspects: firstly, an output filtering system and an EMC system are generally connected to an alternating current side of the photovoltaic grid-connected inverter, and the system is generally composed of components such as an RLC. The photovoltaic grid-connected inverter automatically and synchronously operates along with the sunshine time, the power generation work is performed when the sunlight is sufficient, and the work is stopped when the sunlight is insufficient at night. After the inverter stops working, the internal relay is disconnected, and the output filtering system and the EMC system are still connected with the power grid. This mode causes a number of undesirable problems: the inverter is lost at night, and energy is wasted; ② the service life of the inverter is shortened. And secondly, the photovoltaic grid-connected net cage is only used as a connection point between the photovoltaic grid-connected inverter and the power grid, and can not be actively disconnected under the conditions of overvoltage, undervoltage and the like of the power grid, and equipment can not be actively protected.
SUMMERY OF THE UTILITY MODEL
The utility model aims at providing a safe energy-conserving photovoltaic block terminal system, can be active carry out divide-shut brake control according to sunshine condition, grid voltage condition, leakage current condition etc. can initiatively divide the branch to be connected of disconnected electric wire netting and dc-to-ac converter night, has reduced the night loss of dc-to-ac converter, can improve power factor simultaneously, has high efficiency, safety, energy-conserving advantage.
In order to achieve the above purpose, the utility model adopts the following technical scheme:
a safe and energy-saving photovoltaic distribution box system is connected between a power grid and an inverter and comprises a load switch, a sunshine time synchronization device, an active switching-on and switching-off device, a leakage current detection device and a main controller; the inlet end of the load switch is connected with the power grid end, and the outlet end of the load switch is connected with the inlet end of the active switching-on/off device; the active switching-on and switching-off device comprises a photoelectric coupler, an electromagnetic relay and an electromagnetic contactor, the electromagnetic contactor is connected between the inverter and the load switch, and the main controller is connected with the electromagnetic relay through the photoelectric coupler; the contact of the electromagnetic relay is connected with the control terminal of the electromagnetic contactor;
the leakage current detection device is arranged at a wire outlet end or a wire inlet end of the active switching-on/off device; the leakage current detection device is connected with the main controller, the leakage current detection device detects whether the leakage current of the inverter is abnormal or not, and the main controller sends an opening and closing command to control the opening and closing of the active opening and closing device according to a detection signal of the leakage current detection device;
sunshine time synchronizing device's output links to each other with main control unit, sunshine time synchronizing device includes photosensitive sensor and takes care of the chip, sunshine time synchronizing device passes through photosensitive sensor converts illumination intensity signal into the signal of telecommunication, handles the back through taking care of the chip, compares with preset's illumination intensity threshold value, transmits than high low level signal for main control unit, main control unit sends divide-shut brake instruction according to signal status and gives initiative divide-shut brake device is in order to control its action, it is the operation comparator to take care of the chip.
Furthermore, the leakage current detection device comprises a leakage current transformer, a square wave oscillation circuit, a sampling circuit, a second-order low-pass filter, a comparator circuit and a self-checking circuit, wherein the leakage current transformer comprises a magnetic ring and two secondary windings, the two secondary windings are respectively a detection winding and a self-checking winding, and the detection winding of the leakage current transformer is sequentially connected with the square wave oscillation circuit, the sampling circuit, the second-order low-pass filter and the comparator circuit; and the self-checking winding of the leakage current transformer is connected with the sampling self-checking circuit and used for calibrating the leakage current transformer.
Furthermore, the detection winding and the self-detection winding are wound on the amorphous magnetic ring together.
Furthermore, the leakage current detection device is sleeved on the live wire and the zero wire of the incoming wire end or the outgoing wire end of the active switching-on/off device.
Furthermore, the outlet end of the active switching-on/off device penetrates through the leakage current detection device to be connected with the inverter, and a lightning protection device is further arranged between the leakage current detection device and the inverter.
Furthermore, the leakage current detection device is sleeved at the wire inlet end of the active switching-on/off device; and the outlet end of the active switching-on/off device is connected with the inverter, and a lightning protection device is also arranged between the leakage current detection device and the inverter.
The beneficial effects of the utility model reside in that: the utility model discloses compare with traditional block terminal and can be according to sunshine condition, grid voltage condition, the divide-shut brake action of leakage current control initiative divide-shut brake device. At night, when the inverter does not need to be connected to the grid, the inverter is automatically controlled to be disconnected from the power grid, loss is reduced, and the service life of the inverter is prolonged. The annual night loss of a single 20kW photovoltaic inverter is about 10 kWh-30 kWh, and the annual distributed installed capacity in 2020 of China is about 1.87 hundred million kilowatts, so that the electric energy can be saved by 93.5MWh every year, and about 1.1 million RMB is achieved.
The sunshine time synchronization device of the utility model adopts the photosensitive sensor to detect the illumination intensity, has the function of automatic synchronization inverter power generation time, controls the disconnection of the power grid and the inverter by the main controller according to the illumination intensity at night, reduces the night loss of the inverter, and can improve the power factor at the same time; when the electric wire netting takes place unusually, perhaps when earth leakage protection is unusual for equipment emergence, main control unit also can control initiative divide-shut brake device disconnection, treats that unusual back automatic recovery of eliminating closes a floodgate, the utility model has the advantages of intelligence is initiative, green energy-conservation, the security is high.
Drawings
FIG. 1 is a system block diagram of an embodiment of the present invention;
FIG. 2 is a specific circuit of the sunshine synchronizing device according to the embodiment of the present invention;
FIG. 3 is a circuit diagram of a leakage current detection device according to an embodiment of the present invention;
FIG. 4 is a circuit of an active switching device according to an embodiment of the present invention;
reference numerals: 1. a power grid; 2. a load switch; 3. an active switching-on and switching-off device; 3.1. an electromagnetic contactor; 3.2. an electromagnetic relay; 3.3. a photoelectric coupler; 4. a leakage current detection device; 5. an inverter; 6. a main controller; 7. a sunshine duration synchronizing device; 8. a lightning protection device; 9. a photosensitive sensor; 10. a leakage current transformer; 10.1. detecting the winding; 10.2. self-checking the winding; 11. a square wave oscillation circuit; 12. a self-checking circuit; 13. a second order low pass filter; 14. a comparator circuit; 15. a sampling circuit; 16. and (6) operating a comparator.
Detailed Description
The invention will be further described with reference to the accompanying drawings and specific embodiments:
example one
As shown in fig. 1, a safe and energy-saving photovoltaic distribution box system is applied between a power grid 1 and an inverter 5, and comprises a load switch 2, a sunshine time synchronization device 7, an active switching-on/off device 3 and a leakage current detection device 4, wherein the incoming line end of the load switch 2 is connected with the power grid 1 end, and the outgoing line end of the load switch 2 is connected with the incoming line end of the active switching-on/off device 3; the leakage current detection device 4 is arranged at the outlet end of the active switching-on/off device 3 and is sleeved on the live line and the zero line of the active switching-on/off device 3; the outlet end of the active switching-on/off device 3 passes through the leakage current detection device 4 and is connected with the inverter 5, and a lightning protection device 8 is also arranged between the leakage current detection device 4 and the inverter 5; the output end of the leakage current detection device 4 is connected with the main controller 6, the sunshine hours are synchronously carried out, and the output signal of the leakage current detection device 7 is also connected with the main controller.
As shown in fig. 4, the active switching-on/off device 3 includes a photoelectric coupler 3.3, an electromagnetic relay 3.2 and an electromagnetic contactor 3.1, the electromagnetic contactor 3.1 is connected between the inverter 5 and the load switch 2, and the main controller 6 is connected with the electromagnetic relay 3.2 through the photoelectric coupler 3.3; the contact of the electromagnetic relay 3.2 is connected with the electromagnetic contactor 3.3.
In this embodiment, the active opening and closing device 3 is an electromagnetic contactor 3.1, the main controller 6 controls whether the coil of the electromagnetic contactor 3.1 is connected with the power supply of 220Vac or not through the electromagnetic relay 3.2, when the electromagnetic relay 3.2 is closed, the electromagnetic contactor 3.1 is connected with the power supply of 220Vac, and when the electromagnetic relay 3.2 is disconnected, the electromagnetic contactor 3.1 cannot be connected with the power supply of 220 Vac.
As shown in fig. 3, the leakage current detection device 4 includes a leakage current transformer 10, a square wave oscillation circuit 11, a sampling circuit 15, a second-order low-pass filter 13, and a self-test circuit 12; the leakage current transformer 10 comprises a magnetic ring and two secondary windings, the two secondary windings are a detection winding 10.1 and a self-detection winding 10.2, the detection winding 10.1 and the self-detection winding 10.2 are wound on the amorphous magnetic ring together, the detection winding of the leakage current transformer 10 detects a leakage current signal, the leakage current signal is processed by a square wave oscillation circuit 11, then the processed leakage current signal is converted into a voltage signal by a sampling circuit 15, the converted voltage signal is conditioned by a second-order low-pass filter 13 and converted into a stable direct current voltage signal, the stable direct current voltage signal is compared with a set threshold voltage by a comparator circuit 14, a comparison result is sent to a main controller 6, the main controller 6 sends a corresponding command to the active switching-closing device 3 according to the comparison result of the comparator circuit 14, wherein the square wave oscillation circuit 11 is designed as a conventional circuit, the sampling circuit 15 is a sampling resistor.
Before the leakage current detection device 4 works, the leakage current transformer 10 needs to be calibrated through the self-checking circuit 12, the self-checking circuit 12 is connected to two ends of the self-checking winding 10.2 of the leakage current transformer 10 and used for calibrating the static error of the leakage current transformer 10, a constant 50mA current is supplied to the self-checking winding 10.2, then whether the measured output is 50mA or not is carried out, and if not, the measured output deviates a certain reference quantity.
Sunshine duration synchronizing device 7 includes photosensitive sensor 9 and conditions the chip, sunshine duration synchronizing device 7 passes through photosensitive sensor 9 and converts illumination intensity signal into the signal of telecommunication, handles the back through conditioning the chip and transmits for main control unit 6, main control unit 6 is through the illumination intensity with receiving and the illumination intensity threshold value comparison of preset, sends the divide-shut brake instruction and gives initiative divide-shut brake device 3 with control its action, conditions the chip and is operation comparator 16, as shown in fig. 2, for sunshine duration synchronizing device 7's concrete circuit diagram.
The active switching-on and switching-off device 3 is controlled by the main controller 6 to be switched on and switched off according to external conditions such as power grid voltage, sunlight conditions, leakage current states and the like. When the voltage of the power grid is higher than the grid-connected upper limit Vup _ lmt or lower than the grid-connected lower limit Vdown _ lmt, the main controller 6 controls the active switching-on/off device 3 to switch off, and the inverter 5 is disconnected from the power grid 1; when the sunshine condition is lower than Rdown _ lmt, the main controller 6 controls the active switching-on and switching-off device 3 to switch off, and the connection between the inverter 5 and the power grid 1 is disconnected; when the leakage current is larger than Ileak _ lmt, the main controller 6 controls the active switching-on and switching-off device 3 to be switched on and switched off, and the inverter 5 is disconnected with the power grid 1.
The photosensitive sensor 9 is preferably adopted to track the illumination intensity in real time, the illumination intensity is extremely weak at night, the main controller 6 controls the active switching-on and switching-off device 3 to disconnect the inverter 5 from the power grid 1, and the night loss of the inverter 5 is reduced; the protection device has the functions of leakage current protection and power grid overvoltage and undervoltage protection, and is high in safety.
Example two
The utility model provides an energy-conserving photovoltaic block terminal system of safety is applied to between 1 and the dc-to-ac converter 5 of electric wire netting, including load switch 2, sunshine time synchronization device 7, initiative divide closing device 3, leakage current detection device 4, with the connected mode difference in the embodiment one: the positions of the leakage current detection device 4 and the active opening and closing device 3 are interchanged, and the leakage current detection device is sleeved at the wire inlet end of the active opening and closing device 3; the control method and control logic of this embodiment are the same as those of the first embodiment.
Various other modifications and changes may be made by those skilled in the art based on the above-described technical solutions and concepts, and all such modifications and changes are intended to fall within the scope of the claims.
Claims (6)
1. A safe and energy-saving photovoltaic distribution box system is connected between a power grid and an inverter and is characterized by comprising a load switch, a sunshine time synchronization device, an active opening and closing device, a leakage current detection device and a main controller; the inlet end of the load switch is connected with the power grid end, and the outlet end of the load switch is connected with the inlet end of the active switching-on/off device; the active switching-on and switching-off device comprises a photoelectric coupler, an electromagnetic relay and an electromagnetic contactor, the electromagnetic contactor is connected between the inverter and the load switch, and the main controller is connected with the electromagnetic relay through the photoelectric coupler; the contact of the electromagnetic relay is connected with the control terminal of the electromagnetic contactor;
the leakage current detection device is arranged at a wire outlet end or a wire inlet end of the active switching-on/off device; the main controller sends an opening and closing command to control the active opening and closing device to be closed and opened according to a detection signal of the leakage current detection device;
the output end of the sunshine time synchronizing device is connected with the main controller; the sunshine time synchronizing device comprises a photosensitive sensor and a conditioning chip, the photosensitive sensor converts an illumination intensity signal into an electric signal, and the conditioning chip is an operation comparator.
2. The safe and energy-saving photovoltaic distribution box system according to claim 1, wherein the leakage current detection device comprises a leakage current transformer, a square wave oscillating circuit, a sampling circuit, a second-order low-pass filter, a comparator circuit and a self-checking circuit, the leakage current transformer comprises a magnetic ring and two secondary windings, the two secondary windings are a detection winding and a self-checking winding respectively, and the detection winding of the leakage current transformer is sequentially connected with the square wave oscillating circuit, the sampling circuit, the second-order low-pass filter and the comparator circuit; and the self-checking winding of the leakage current transformer is connected with the sampling self-checking circuit and used for calibrating the leakage current transformer.
3. A safe and energy-saving photovoltaic distribution box system according to claim 1, wherein the leakage current detection device is sleeved on the live line and the neutral line of the active switching-on/off device.
4. A safe and energy-saving photovoltaic distribution box system according to claim 2, wherein the secondary winding and the self-checking winding of the leakage current transformer are wound on the amorphous magnetic ring together.
5. The safe and energy-saving photovoltaic distribution box system according to claim 1, wherein the outlet of the active switching-closing device is connected to the inverter through the leakage current detection device, and a lightning protection device is further disposed between the leakage current detection device and the inverter.
6. A safe and energy-saving photovoltaic distribution box system according to claim 1, wherein the leakage current detection device is sleeved at the incoming line end of the active switching-on/off device; and the outlet end of the active switching-on/off device is connected with the inverter, and a lightning protection device is also arranged between the leakage current detection device and the inverter.
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| Application Number | Priority Date | Filing Date | Title |
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| CN202120576023.2U CN214337575U (en) | 2021-03-22 | 2021-03-22 | Safe and energy-saving photovoltaic power distribution box system |
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| CN202120576023.2U CN214337575U (en) | 2021-03-22 | 2021-03-22 | Safe and energy-saving photovoltaic power distribution box system |
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Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US11538628B2 (en) | 2019-12-02 | 2022-12-27 | Panoramic Power Ltd. | Self calibration by signal injection |
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2021
- 2021-03-22 CN CN202120576023.2U patent/CN214337575U/en active Active
Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US11538628B2 (en) | 2019-12-02 | 2022-12-27 | Panoramic Power Ltd. | Self calibration by signal injection |
| US11705275B2 (en) * | 2019-12-02 | 2023-07-18 | Panoramic Power Ltd. | Self calibration by double signal sampling |
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