CN113067547B - Monitoring device, monitoring method of photovoltaic string and readable storage medium - Google Patents
Monitoring device, monitoring method of photovoltaic string and readable storage medium Download PDFInfo
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- 238000012544 monitoring process Methods 0.000 title claims abstract description 62
- 238000012806 monitoring device Methods 0.000 title claims abstract description 58
- 238000000034 method Methods 0.000 title claims abstract description 56
- 230000002159 abnormal effect Effects 0.000 claims abstract description 28
- 238000001514 detection method Methods 0.000 claims description 42
- 238000010248 power generation Methods 0.000 claims description 31
- 238000007599 discharging Methods 0.000 claims description 16
- 230000005611 electricity Effects 0.000 claims description 3
- 230000000694 effects Effects 0.000 abstract description 7
- 238000004146 energy storage Methods 0.000 description 9
- 238000004891 communication Methods 0.000 description 5
- 238000010586 diagram Methods 0.000 description 5
- 230000006870 function Effects 0.000 description 5
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- H—ELECTRICITY
- H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
- H02S—GENERATION OF ELECTRIC POWER BY CONVERSION OF INFRARED RADIATION, VISIBLE LIGHT OR ULTRAVIOLET LIGHT, e.g. USING PHOTOVOLTAIC [PV] MODULES
- H02S50/00—Monitoring or testing of PV systems, e.g. load balancing or fault identification
- H02S50/10—Testing of PV devices, e.g. of PV modules or single PV cells
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- G—PHYSICS
- G01—MEASURING; TESTING
- G01R—MEASURING ELECTRIC VARIABLES; MEASURING MAGNETIC VARIABLES
- G01R19/00—Arrangements for measuring currents or voltages or for indicating presence or sign thereof
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- Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
- Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
- Y02E—REDUCTION OF GREENHOUSE GAS [GHG] EMISSIONS, RELATED TO ENERGY GENERATION, TRANSMISSION OR DISTRIBUTION
- Y02E10/00—Energy generation through renewable energy sources
- Y02E10/50—Photovoltaic [PV] energy
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Abstract
The invention discloses a monitoring method, a monitoring device and a readable storage medium of a photovoltaic string, wherein the monitoring method of the photovoltaic string comprises the following steps: acquiring a voltage value detected by a voltage sensor; when the voltage value detected by the voltage sensor is smaller than a preset voltage value, closing a first switch unit; acquiring a first current value detected by a first current sensor; when the first current value is smaller than a first preset current value, the photovoltaic string is judged to be abnormal, and the effect of monitoring the abnormal condition of the photovoltaic string is achieved.
Description
Technical Field
The invention relates to the technical field of photovoltaics, in particular to a monitoring device, a monitoring method of a photovoltaic string and a readable storage medium.
Background
The existing photovoltaic power generation stations are generally built in remote areas, no specially-assigned person is responsible for daily management, the safety of a photovoltaic module is poor, and when the photovoltaic module is abnormal (such as failure, theft and the like), a photovoltaic power generation system cannot timely know the detailed conditions of a photovoltaic group string, so that abnormal power generation is caused for a long time, power generation loss is caused, and the power generation condition of the photovoltaic power generation system is influenced.
The above is only for the purpose of assisting understanding of the technical aspects of the present invention, and does not represent an admission that the above is prior art.
Disclosure of Invention
The invention mainly aims to provide a monitoring method, a monitoring device and a readable storage medium of a photovoltaic string, and aims to achieve the effect of monitoring the abnormal condition of the photovoltaic string.
To achieve the above object, the present invention provides a monitoring device, comprising:
detecting the positive electrode;
detecting a negative electrode;
the discharging loop is connected between the detection positive electrode and the detection negative electrode and comprises a battery unit, a first switch unit and a resistor which are connected in series;
a first current sensor connected in series with the discharge circuit;
and the voltage sensor is connected between the detection positive electrode and the detection negative electrode so as to detect the voltage between the detection positive electrode and the detection negative electrode.
Optionally, the monitoring device further comprises:
the charging circuit is connected between the detection positive electrode and the detection negative electrode and comprises the battery unit and a second switch unit which are connected in series;
a second current sensor connected in series on the charging loop.
Optionally, the discharge circuit further comprises:
a first diode, wherein the first diode is connected in series on the discharge loop, the anode of the first diode is connected with the cathode of the battery unit, and the cathode of the first diode is connected with the detection cathode;
the charging circuit further includes:
and the second diode is connected in series on the charging loop, the anode of the second diode is connected with the detection anode, and the cathode of the second diode is connected with the anode of the battery unit.
Optionally, the monitoring device further comprises:
an output positive electrode connected with the detection positive electrode through a third switching unit;
and the output negative electrode is connected with the detection negative electrode through a fourth switch unit.
In addition, in order to achieve the above object, the present invention provides a monitoring method for a photovoltaic string, which is applied to the above monitoring apparatus, the monitoring apparatus is connected in parallel with the photovoltaic string and an output device in a photovoltaic power generation system, and the monitoring method for the photovoltaic string comprises the following steps:
acquiring a voltage value detected by a voltage sensor;
when the voltage value detected by the voltage sensor is smaller than a preset voltage value, closing a first switch unit;
acquiring a first current value detected by a first current sensor;
and when the first current value is smaller than a first preset current value, judging that the photovoltaic string is abnormal.
Optionally, after the step of determining that the photovoltaic string is abnormal when the first current value is smaller than a first preset current value, the method further includes:
turning off the first switching unit;
and/or outputting prompt information of the abnormity of the photovoltaic string.
Optionally, after the step of obtaining the voltage value detected by the voltage sensor, the monitoring method for the photovoltaic string further includes:
and when the voltage value detected by the voltage inductor is greater than or equal to the preset voltage value, closing the second switch unit so as to charge the battery unit through the photovoltaic group string.
Optionally, when the voltage value detected by the voltage sensor is greater than or equal to the preset voltage value, the step of closing the second switch unit includes:
when the voltage value detected by the voltage inductor is greater than or equal to the preset voltage value, closing the third switching unit and the fourth switching unit;
acquiring the current electric quantity stored in the battery unit;
and when the electric storage quantity is smaller than the preset electric storage quantity, closing the second switch unit.
Optionally, when the power storage amount is less than the preset power storage amount, after the step of closing the second switch unit, the method further includes:
when a second current value detected by the second current sensor is greater than or equal to a second preset current value, the second switch unit is switched off;
or when the electric storage capacity of the battery unit is monitored to be larger than or equal to the preset electric storage capacity, the second switch unit is switched off.
Optionally, after the step of obtaining the first current value detected by the first current sensor, the method further includes:
when the first current value is larger than or equal to the first preset current value, outputting the first current value;
and after the preset time, returning to the step of acquiring the first current value detected by the first current sensor.
In addition, in order to achieve the above object, the present invention also provides a monitoring device, including: the monitoring program of the photovoltaic string is stored on the memory and can run on the processor, and when being executed by the processor, the monitoring program of the photovoltaic string realizes the steps of the monitoring method of the photovoltaic string.
In addition, to achieve the above object, the present invention further provides a readable storage medium, where a monitoring program of a pv string is stored, and the monitoring program of the pv string is executed by a processor to implement the steps of the monitoring method of the pv string as described above.
According to the monitoring method, the monitoring device and the readable storage medium of the photovoltaic string, which are provided by the embodiment of the invention, the voltage value detected by the voltage sensor is obtained; when the voltage value detected by the voltage sensor is smaller than a preset voltage value, closing a first switch unit; acquiring a first current value detected by a first current sensor; when the first current value is smaller than a first preset current value, the photovoltaic string is judged to be abnormal, and the effect of monitoring the abnormal condition of the photovoltaic string is achieved.
Drawings
Fig. 1 is a schematic diagram of a hardware architecture of a monitoring device according to an embodiment of the present invention;
FIG. 2 is a schematic structural diagram of a monitoring device according to an embodiment of the present invention;
FIG. 3 is a schematic view of another structure of a monitoring device according to an embodiment of the present invention;
fig. 4 is a schematic flow chart of a monitoring method of a photovoltaic string according to a first embodiment of the present invention;
fig. 5 is a schematic flow chart of a monitoring method for photovoltaic strings according to a second embodiment of the present invention;
fig. 6 is a schematic flow chart of a monitoring method for photovoltaic strings according to a third embodiment of the present invention;
fig. 7 is a schematic flowchart of a monitoring method for photovoltaic strings according to a fourth embodiment of the present invention;
fig. 8 illustrates a photovoltaic power generation system with a monitoring function according to an embodiment of the present invention;
fig. 9 is another photovoltaic power generation system with a monitoring function according to an embodiment of the present invention.
The implementation, functional features and advantages of the objects of the present invention will be further explained with reference to the accompanying drawings.
Detailed Description
It should be understood that the specific embodiments described herein are merely illustrative of the invention and are not intended to limit the invention.
The existing photovoltaic power generation stations are generally built in remote areas, no specially-assigned person is responsible for daily management, the safety of a photovoltaic module is poor, and when the photovoltaic module is abnormal (such as failure, theft and the like), a photovoltaic power generation system cannot timely know the detailed conditions of a photovoltaic group string, so that abnormal power generation is caused for a long time, power generation loss is caused, and the power generation condition of the photovoltaic power generation system is influenced.
In order to solve the above-mentioned defects, an embodiment of the present invention provides a monitoring method, a monitoring device, and a readable storage medium for a photovoltaic string, where the monitoring method for a photovoltaic string mainly includes the following steps:
acquiring a voltage value detected by a voltage sensor;
when the voltage value detected by the voltage sensor is smaller than a preset voltage value, closing a first switch unit;
acquiring a first current value detected by a first current sensor;
and when the first current value is smaller than a first preset current value, judging that the photovoltaic string is abnormal.
According to the scheme, the voltage value of the photovoltaic string is detected through the voltage sensor, whether the photovoltaic string is in a power generation state or not is judged according to the voltage value, the first switch unit is closed when the photovoltaic string is not in the power generation state, the battery unit is controlled to start discharging, so that the discharging loop generates current, then the current value is detected through the current inductor, whether the discharging loop is normal or not is judged according to the current value, namely whether the photovoltaic string is abnormal or not is judged, and the effect of monitoring the abnormal condition of the photovoltaic string is achieved.
As shown in fig. 1, fig. 1 is a schematic diagram of a hardware architecture of a monitoring device according to an embodiment of the present invention.
As shown in fig. 1, the monitoring device may include: a processor 1001, such as a CPU, a user interface 1003, a network interface 1004, a memory 1005, a communication bus 1002. Wherein a communication bus 1002 is used to enable connective communication between these components. The user interface 1003 may comprise a Display screen (Display), an input unit such as keys, etc., and the optional user interface 1003 may also comprise a standard wired interface, a wireless interface. The network interface 1004 may optionally include a standard wired interface, a wireless interface (e.g., WI-FI interface). The memory 1005 may be a high-speed RAM memory or a non-volatile memory (e.g., a magnetic disk memory). The memory 1005 may alternatively be a storage device separate from the processor 1001.
Those skilled in the art will appreciate that the hardware architecture of the monitoring device shown in fig. 1 does not constitute a limitation of the monitoring device, and may include more or fewer components than those shown, or some components in combination, or a different arrangement of components.
As shown in fig. 1, a memory 1005, which is a kind of computer storage medium, may include therein an operating system, a network communication module, a user interface module, and a monitoring program of the photovoltaic string.
In the monitoring apparatus shown in fig. 1, the network interface 1004 is mainly used for connecting to a backend server and performing data communication with the backend server; the processor 1001 may be configured to invoke a monitoring program for the photovoltaic string stored in the memory 1005 and perform the following operations:
acquiring a voltage value detected by a voltage sensor;
when the voltage value detected by the voltage sensor is smaller than a preset voltage value, closing a first switch unit;
acquiring a first current value detected by a first current sensor;
and when the first current value is smaller than a first preset current value, judging that the photovoltaic string is abnormal.
Further, the processor 1001 may be configured to call a monitoring program of the pv string stored in the memory 1005, and further perform the following operations:
turning off the first switching unit;
and/or outputting prompt information of the abnormity of the photovoltaic string.
Further, the processor 1001 may be configured to call a monitoring program of the pv string stored in the memory 1005, and further perform the following operations:
and when the voltage value detected by the voltage inductor is greater than or equal to the preset voltage value, closing the second switch unit so as to charge the battery unit through the photovoltaic group string.
Further, the processor 1001 may be configured to call a monitoring program of the pv string stored in the memory 1005, and further perform the following operations:
when the voltage value detected by the voltage inductor is greater than or equal to the preset voltage value, closing the third switching unit and the fourth switching unit;
acquiring the current electric quantity stored in the battery unit;
and when the electric storage quantity is smaller than the preset electric storage quantity, closing the second switch unit.
Further, the processor 1001 may be configured to call a monitoring program of the pv string stored in the memory 1005, and further perform the following operations:
when a second current value detected by the second current sensor is greater than or equal to a second preset current value, the second switch unit is switched off;
or when the electric storage capacity of the battery unit is monitored to be larger than or equal to the preset electric storage capacity, the second switch unit is switched off.
Further, the processor 1001 may be configured to call a monitoring program of the pv string stored in the memory 1005, and further perform the following operations:
when the first current value is larger than or equal to the first preset current value, outputting the first current value;
and after the preset time, returning to the step of acquiring the first current value detected by the first current sensor.
Referring to fig. 2, fig. 2 is a schematic structural diagram of a monitoring device according to an embodiment of the present invention.
Specifically, the monitoring device includes: the battery pack comprises a detection anode Pvin +, a detection cathode Pvin-, a discharge circuit and a voltage sensor 20, wherein the discharge circuit is connected between the detection anode Pvin + and the detection cathode Pvin-, the discharge circuit comprises a battery unit 10, a first switch unit K1 and a resistor R which are connected in series, a first current sensor CT1 is connected in series on the discharge circuit, and the voltage sensor 20 is connected between the detection anode Pvin + and the detection cathode Pvin-to detect the voltage between the detection anode Pvin + and the detection cathode Pvin-.
And a detection positive electrode Pvin + of the monitoring device can be connected with a positive electrode of the photovoltaic string D, and a detection negative electrode Pvin-of the monitoring device can be connected with a negative electrode of the photovoltaic string D, so that the effect of monitoring the photovoltaic string through the monitoring device is achieved. After the photovoltaic string D is connected to the circuit, the photovoltaic string D can function as a diode, so that the photovoltaic string D can be equivalent to a diode in this embodiment.
In the technical solution disclosed in this embodiment, the monitoring device may detect the voltage between the positive electrode Pvin + and the negative electrode Pvin-through the voltage sensor 20, that is, detect the voltage of the photovoltaic string D, control the battery unit 10 to discharge when it is detected that the photovoltaic string D is not generating power, detect the current of the discharge circuit through the first current sensor CT1, and determine whether the photovoltaic string D is abnormal according to the current of the discharge circuit.
Based on the foregoing embodiments, referring to fig. 3, fig. 3 is another schematic structural diagram of a monitoring device according to an embodiment of the present invention.
Alternatively, since the stored electric energy of the battery unit 10 is limited, in order to improve the service time of the monitoring device, the monitoring device may further include a charging circuit, wherein the charging circuit is connected between the detection positive electrode Pvin + and the detection negative electrode Pvin-, the charging circuit includes the battery unit 10 and the second switching unit K2 connected in series, and the second current sensor CT2 is connected in series to the charging circuit.
Optionally, since the string D of photovoltaic groups may generate a reverse voltage, which may pose a threat to the monitoring device, especially to the battery unit 10, in order to ensure the safety of the battery unit 10 and to ensure the current flow of the discharging loop and the charging loop, the discharging loop further includes a first diode D1, the first diode D1 is connected in series to the discharging loop, the anode of the first diode D1 is connected to the cathode of the battery unit 10, and the cathode of the first diode D1 is connected to the detection cathode Pvin —; the charging circuit further comprises a second diode D2, the second diode D2 is connected in series to the charging circuit, the anode of the second diode D2 is connected to the detection anode Pvin +, and the cathode of the second diode D2 is connected to the anode of the battery cell 10.
Optionally, since the monitoring device is an external device and is connected to the photovoltaic string, in order to avoid an influence of the monitoring device on the photovoltaic power generation system, the monitoring device may further include: an output positive electrode Pvout +, which is connected to the detection positive electrode Pvin + via a third switching unit K3; negative output terminal Pvout-, which is connected to negative detection terminal Pvin-via fourth switching unit K4.
Specifically, because the output devices such as the energy storage device and the photovoltaic inverter can be connected between the detection positive electrode Pvin + and the detection negative electrode Pvin-, when the third switching unit K3 and the fourth switching unit K4 are not turned off, after the battery unit 10 discharges current, current is generated among the backflow circuits of the battery unit 10, the first current sensor CT1, the third switching unit K3, the output device, the fourth switching unit K4, the first diode D1, the resistor R, and the first switching unit K1, so that the judgment process of the monitoring device for judging whether the photovoltaic group string D is abnormal is influenced.
Therefore, before the monitoring device starts monitoring the photovoltaic string D, that is, when the voltage value detected by the voltage sensor 20 is smaller than the preset voltage value, the third switching unit K3 and the fourth switching unit K4 are turned off, so as to prevent the first current sensor CT1 from detecting a wrong current, and improve the accuracy of the monitoring device in determining the abnormality of the photovoltaic string D.
Alternatively, since the battery performance of the battery unit 10 disposed inside the monitoring device may be different, the battery unit 10 may generate a short-time continuous current (i.e., a continuous current for a fixed time period) or a transient pulse current, which is not limited herein.
Optionally, the monitoring device may further comprise a fifth switching unit K5 for controlling the switching on and off of the monitoring device.
As shown in fig. 4, in the first embodiment of the monitoring method of a photovoltaic string of the present invention, the monitoring method of a photovoltaic string includes the following steps:
step S10, acquiring a voltage value detected by a voltage sensor;
step S20, when the voltage value detected by the voltage sensor is smaller than a preset voltage value, closing a first switch unit;
step S30, acquiring a first current value detected by the first current sensor;
and step S40, when the first current value is smaller than a first preset current value, judging that the photovoltaic string is abnormal.
In this embodiment, the method for detecting the pv string is applied to the monitoring apparatus as described above, and the monitoring apparatus is connected in parallel with the pv string and the output device in the pv power generation system, where the output device may be a junction device, a pv inverter, an energy storage device, and the like. The voltage sensor is used for detecting the voltage of the photovoltaic string connected with the monitoring device, and the preset voltage value is a threshold value for judging whether the photovoltaic string is in a power generation state. The first current sensor is used for detecting current of a loop where the current is located, and the first preset current value is a threshold value for judging whether the photovoltaic string is abnormal or not.
After the monitoring device is started, a voltage value detected by the voltage sensor is obtained through the processor, the voltage value is compared with a preset voltage value, when the voltage value is smaller than the preset voltage value, the photovoltaic group string is judged not to be in a power generation state, then the first switch unit is closed, the battery unit is controlled to start discharging, and therefore current generated by the battery unit flows through the first switch unit, the resistor, the first diode, the fifth switch unit, the detection cathode, the photovoltaic group string, the detection anode and the first current sensor to form a loop; since the battery unit is damaged by the excessive current/voltage, a resistor may be further disposed in the monitoring device to consume the current/voltage generated by the battery unit. And then, acquiring a first current value detected by the first current sensor, comparing the first current value with a first preset current value, and judging that the photovoltaic string is abnormal when the first current value is smaller than the first preset current value, namely, the monitoring device cannot form a loop with the photovoltaic string due to the abnormality of the photovoltaic string, so that the current cannot be detected or a tiny current cannot be detected.
In the technical scheme disclosed in this embodiment, the voltage value of the photovoltaic string is detected by the voltage sensor, so as to determine whether the photovoltaic string is in a power generation state according to the voltage value, and when the photovoltaic string is not in the power generation state, the first switch unit is closed, and the battery unit is controlled to start discharging, so that the discharging loop generates current, and then the current value is detected by the current inductor, so as to determine whether the discharging loop is normal according to the current value, that is, whether the photovoltaic string is abnormal is determined, and the effect of monitoring the abnormal condition of the photovoltaic string is achieved.
Optionally, as shown in fig. 5, based on the first embodiment, in a second embodiment of the monitoring method for a photovoltaic string of the present invention, after step S40, the method further includes:
step S50, turning off the first switch unit;
and step S60, and/or outputting prompt information of the abnormity of the photovoltaic string.
In this embodiment, after determining that there is an abnormality in the photovoltaic string, the processor may turn off the first switch unit, or control the battery unit to stop discharging, so as to end the monitoring process of the monitoring device.
The processor may further output prompt information of the photovoltaic string after determining that the photovoltaic string is abnormal, and may exemplarily send the prompt information to a mobile terminal/a photovoltaic monitoring system of a user through a wired network or a wireless network; or the output unit of the monitoring device outputs prompt information, such as the display screen outputs prompt information, the buzzer outputs prompt tones and the like.
In the technical scheme disclosed in this embodiment, after it is determined that the photovoltaic string has the prompt information, the monitoring process is ended by turning off the first switch unit, and the user is prompted that the photovoltaic string is abnormal by outputting the prompt information.
Optionally, as shown in fig. 6, based on the first embodiment, in a third embodiment of the monitoring method for a photovoltaic string of the present invention, after step S20, the method further includes:
and step S70, when the voltage value detected by the voltage sensor is greater than or equal to the preset voltage value, closing a second switch unit to charge the battery unit through the photovoltaic string.
In this embodiment, when the voltage value detected by the voltage sensor is greater than or equal to the preset voltage value, the processor determines that the photovoltaic string is in the power generation state, and then closes the second switch unit, so that the current generated by the photovoltaic string can flow through the second diode, the second switch unit, the battery unit, the second current sensor and the fifth switch unit, so as to charge the battery unit through the current generated by the photovoltaic string.
Exemplarily, the step S70 further includes:
step S71, when the voltage value detected by the voltage sensor is greater than or equal to the preset voltage value, closing the third switching unit and the fourth switching unit;
step S72, acquiring the current electric storage capacity of the battery unit;
and step S73, when the electricity storage quantity is smaller than the preset electricity storage quantity, closing the second switch unit.
In this embodiment, when the voltage value detected by the voltage sensor is greater than or equal to the preset voltage value, the processor determines that the photovoltaic string is in a power generation state, and then closes the third switching unit and the fourth switching unit, so that the current generated by the photovoltaic string can flow to the output device; meanwhile, the current electric storage quantity of the battery unit can be acquired, when the electric storage quantity is smaller than the preset electric storage quantity, the battery unit is judged to have low energy storage and needs to be charged, and the second switch unit is closed at the moment so as to charge the battery unit.
Optionally, after the step S73, the method further includes:
step S74, turning off the second switch unit when the second current value detected by the second current sensor is greater than or equal to a second preset current value;
step S75, or when it is monitored that the power storage amount of the battery unit is greater than or equal to the preset power storage amount, turning off the second switch unit.
In this embodiment, the second preset current value is a maximum current value that the battery unit can bear; the preset electric storage amount is the upper limit of the energy storage of the battery unit.
And after the second switch unit is closed, the processor acquires a second current value detected by the second current sensor in real time, compares the second current value with a second preset current value, judges that the current generated by the photovoltaic string is overlarge when the second current value is greater than or equal to the second preset current value, and then disconnects the second switch unit to avoid the damage of the overlarge current to the battery unit.
The processor can also monitor the electric energy storage amount of the battery unit in real time after the second switch unit is closed, judge that the stored energy of the battery unit reaches the upper limit of the stored energy when the electric energy storage amount is monitored to be larger than or equal to the preset electric energy storage amount, and then disconnect the second switch unit.
In the technical scheme disclosed in this embodiment, the second switch unit is closed to charge the battery unit, so as to prolong the working time of the monitoring device.
Optionally, as shown in fig. 7, based on the first embodiment, in a fourth embodiment of the monitoring method for a photovoltaic string of the present invention, after step S30, the method further includes:
step S80, when the first current value is greater than or equal to the first preset current value, outputting the first current value;
and step S90, after the preset time, returning to the step of acquiring the first current value detected by the first current sensor.
In this embodiment, when the first current value is greater than or equal to the first preset current value, the processor preliminarily determines that the photovoltaic string is in a normal state, and then outputs the first current value, so that a user further determines whether the photovoltaic string is abnormal according to the first current value; the processor also starts timing after acquiring the first current value detected by the first current sensor, acquires the first current value detected by the first current sensor again after the timing duration reaches the preset duration, and then executes the monitoring process.
In the technical scheme disclosed in the embodiment, the first current value detected by the first current sensor is obtained at regular time, so that the effect of monitoring the photovoltaic string for a long time is achieved.
Optionally, as shown in fig. 8, fig. 8 is a photovoltaic power generation system with a monitoring function according to an embodiment of the present invention, where the photovoltaic power generation system includes at least one monitoring device, and each monitoring device may be connected to at least one photovoltaic string Pv; at least one photovoltaic inverter, each photovoltaic inverter being connectable to at least two monitoring devices, and each photovoltaic inverter being connectable to an input of the power grid.
Alternatively, as shown in fig. 9, fig. 9 is another photovoltaic power generation system with monitoring function according to an embodiment of the present invention, where the photovoltaic power generation system includes at least one monitoring device, and each monitoring device may be connected to at least one photovoltaic string Pv; at least one energy storage device, each energy storage device may be associated with at least two monitoring devices.
In addition, an embodiment of the present invention further provides a monitoring apparatus, where the monitoring apparatus includes a memory, a processor, and a monitoring program of a pv string that is stored in the memory and is capable of running on the processor, and when the monitoring program of the pv string is executed by the processor, the steps of the monitoring method of the pv string according to the above embodiments are implemented.
In addition, an embodiment of the present invention further provides a readable storage medium, where a monitoring program of a pv string is stored on the readable storage medium, and when the monitoring program of the pv string is executed by a processor, the steps of the monitoring method of the pv string according to the above embodiments are implemented.
It should be noted that, in this document, the terms "comprises," "comprising," or any other variation thereof, are intended to cover a non-exclusive inclusion, such that a process, method, article, or system that comprises a list of elements does not include only those elements but may include other elements not expressly listed or inherent to such process, method, article, or system. Without further limitation, an element defined by the phrase "comprising an … …" does not exclude the presence of other like elements in a process, method, article, or system that comprises the element.
The above-mentioned serial numbers of the embodiments of the present invention are merely for description and do not represent the merits of the embodiments.
Through the above description of the embodiments, those skilled in the art will clearly understand that the method of the above embodiments can be implemented by software plus a necessary general hardware platform, and certainly can also be implemented by hardware, but in many cases, the former is a better implementation manner. Based on such understanding, the technical solution of the present invention may be embodied in the form of a software product, which is stored in a storage medium (e.g. ROM/RAM, magnetic disk, optical disk) as described above and includes instructions for causing a monitoring device to execute the method according to the embodiments of the present invention.
The above description is only a preferred embodiment of the present invention, and is not intended to limit the scope of the present invention, and all equivalent structures or equivalent processes performed by the present invention or directly or indirectly applied to other related technical fields are also included in the scope of the present invention.
Claims (11)
1. A monitoring device for a photovoltaic string, the monitoring device comprising:
detecting the positive electrode;
detecting a negative electrode;
the discharging loop is connected between the detection positive electrode and the detection negative electrode, the discharging loop comprises a battery unit, a first switch unit and a resistor which are connected in series, and the battery unit is used for discharging to the discharging loop when the photovoltaic string does not generate electricity;
the first current sensor is connected in series with the discharge loop and used for detecting a first current value of the discharge loop;
the voltage sensor is connected between the detection positive electrode and the detection negative electrode so as to detect a voltage value between the detection positive electrode and the detection negative electrode, and the power generation state of the photovoltaic string is judged according to the voltage value;
the monitoring method applied to the photovoltaic string of the monitoring device comprises the following steps:
acquiring a voltage value detected by a voltage sensor;
when the voltage value detected by the voltage sensor is smaller than a preset voltage value, closing a first switch unit;
acquiring a first current value detected by a first current sensor;
and when the first current value is smaller than a first preset current value, judging that the photovoltaic string is abnormal.
2. The monitoring device of claim 1, further comprising:
the charging circuit is connected between the detection positive electrode and the detection negative electrode and comprises the battery unit and a second switch unit which are connected in series;
a second current sensor connected in series on the charging loop.
3. The monitoring device of claim 2, further comprising:
an output positive electrode connected with the detection positive electrode through a third switching unit;
and the output negative electrode is connected with the detection negative electrode through a fourth switch unit.
4. A method for monitoring a pv string, which is applied to the monitoring apparatus according to claim 1, wherein the monitoring apparatus is connected in parallel with the pv string and an output device in a pv power generation system, and the method for monitoring the pv string comprises the following steps:
acquiring a voltage value detected by a voltage sensor;
when the voltage value detected by the voltage sensor is smaller than a preset voltage value, closing a first switch unit;
acquiring a first current value detected by a first current sensor;
and when the first current value is smaller than a first preset current value, judging that the photovoltaic string is abnormal.
5. The method for monitoring photovoltaic string according to claim 4, wherein after the step of determining that the photovoltaic string is abnormal when the first current value is smaller than the first preset current value, the method further comprises:
turning off the first switching unit;
and/or outputting prompt information of the abnormity of the photovoltaic string.
6. The method for monitoring a pv string according to claim 4, applied to the monitoring apparatus according to claim 2, wherein after the step of obtaining the voltage value detected by the voltage sensor, the method for monitoring a pv string further comprises:
and when the voltage value detected by the voltage sensor is greater than or equal to the preset voltage value, closing a second switch unit so as to charge the battery unit through the photovoltaic group string.
7. The method for monitoring a photovoltaic string according to claim 6, wherein when the voltage value detected by the voltage sensor is greater than or equal to the preset voltage value, the step of closing the second switch unit comprises:
when the voltage value detected by the voltage sensor is greater than or equal to the preset voltage value, closing the third switching unit and the fourth switching unit;
acquiring the current electric quantity stored in the battery unit;
and when the electric storage quantity is smaller than the preset electric storage quantity, closing the second switch unit.
8. The method for monitoring a photovoltaic string according to claim 7, wherein after the step of closing the second switch unit when the stored energy is less than the preset stored energy, the method further comprises:
when a second current value detected by a second current sensor is greater than or equal to a second preset current value, the second switch unit is switched off;
or when the electric storage capacity of the battery unit is monitored to be larger than or equal to the preset electric storage capacity, the second switch unit is switched off.
9. The method for monitoring a photovoltaic string according to claim 4, wherein the step of obtaining the first current value detected by the first current sensor is followed by further comprising:
when the first current value is larger than or equal to the first preset current value, outputting the first current value;
and after the preset time, returning to the step of acquiring the first current value detected by the first current sensor.
10. A monitoring device for a photovoltaic string, the monitoring device comprising: memory, processor and a monitoring program of a string of photovoltaic groups stored on the memory and executable on the processor, the monitoring program of a string of photovoltaic groups implementing the steps of the monitoring method of a string of photovoltaic groups according to any one of claims 4 to 9 when executed by the processor.
11. A readable storage medium, wherein a monitoring program of a pv string is stored thereon, and when executed by a processor, the monitoring program of the pv string implements the steps of the monitoring method of the pv string according to any one of claims 4 to 9.
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| CN205407336U (en) * | 2016-03-03 | 2016-07-27 | 阳光电源股份有限公司 | Electrostatic discharge carrier wave transmitting system and photovoltaic cell board monitored control system |
| CN206595720U (en) * | 2017-02-08 | 2017-10-27 | 浙江佳明天和缘光伏科技有限公司 | A kind of photovoltaic generation monitoring system of got lines crossed based on group cable communication and single-point current detecting |
| CN208675189U (en) * | 2018-08-01 | 2019-03-29 | 北京智芯微电子科技有限公司 | Photovoltaic module monitoring device based on Big Dipper short message |
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