CN111969952A - Fault detection method, device and equipment for photovoltaic string and computer readable storage medium - Google Patents
Fault detection method, device and equipment for photovoltaic string and computer readable storage medium Download PDFInfo
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- H02S—GENERATION OF ELECTRIC POWER BY CONVERSION OF INFRARED RADIATION, VISIBLE LIGHT OR ULTRAVIOLET LIGHT, e.g. USING PHOTOVOLTAIC [PV] MODULES
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Abstract
The invention discloses a fault detection method, a fault detection device, equipment and a computer-readable storage medium of a photovoltaic string, wherein the method comprises the steps of acquiring a voltage value of an MPPT unit; when the voltage value of the MPPT unit is larger than a first preset voltage value, determining a first electrical performance parameter of each photovoltaic string, wherein the first electrical performance parameter comprises at least one of a first current and a first voltage; when the voltage value of the MPPT unit is smaller than a second preset voltage value, determining a second electrical performance parameter of each photovoltaic string, wherein the second preset voltage value is smaller than the first preset voltage value, and the second electrical performance parameter comprises at least one of a second current and a second voltage; and determining a faulty photovoltaic string according to the first electrical performance parameter and the second electrical performance parameter. The invention saves the cost of photovoltaic string fault detection.
Description
Technical Field
The invention relates to the technical field of photovoltaic power generation, in particular to a method, a device and equipment for detecting faults of a photovoltaic string and a computer readable storage medium.
Background
Solar energy becomes one of the most potential renewable energy sources with the advantages of abundant resources, wide distribution, cleanness and the like, the solar photovoltaic power generation industry develops rapidly, and the market application scale is continuously enlarged. The solar photovoltaic power generation industry has higher and higher requirements on reliable and stable operation of a photovoltaic power generation system, so that the solar photovoltaic power generation industry is of great importance to operation and maintenance of the photovoltaic system. The photovoltaic string is used as an important component of a photovoltaic power generation system, the price is high, so that the photovoltaic string is particularly important for fault detection, and for a large photovoltaic power station, the number of the photovoltaic strings is large, and once a fault is generated, troubleshooting and diagnosis are difficult.
In the related technical solution, an inverter with an IV characteristic curve scanning function is required to detect a fault condition of a photovoltaic string, but at the present stage, the number of inverters with the IV characteristic curve scanning function is still small, and the price is high. For a large number of inverters without the IV characteristic curve scanning function, the inverter software and the communication system need to be upgraded, so that the cost of the photovoltaic string fault detection is high.
Disclosure of Invention
The invention mainly aims to provide a method, a device and equipment for detecting faults of photovoltaic strings and a computer readable storage medium, and aims to solve the problem of high cost of fault detection of the photovoltaic strings.
In order to achieve the above object, the invention provides a method for detecting a fault of a photovoltaic string, which comprises the following steps:
acquiring a voltage value of the MPPT unit;
when the voltage value of the MPPT unit is larger than a first preset voltage value, determining a first electrical performance parameter of each photovoltaic string, wherein the first electrical performance parameter comprises at least one of a first current and a first voltage;
when the voltage value of the MPPT unit is smaller than a second preset voltage value, determining a second electrical performance parameter of each photovoltaic string, wherein the second preset voltage value is smaller than the first preset voltage value, and the second electrical performance parameter comprises at least one of a second current and a second voltage;
and determining a faulty photovoltaic string according to the first electrical performance parameter and the second electrical performance parameter.
In one embodiment, the step of determining a faulty photovoltaic string as a function of the first electrical performance parameter and the second electrical performance parameter further comprises:
determining an electrical property parameter of the plurality of first electrical property parameters having a largest parameter value as a first target parameter, determining a first deviation parameter of each of the first electrical property parameters other than the first target parameter from the first target parameter, the first deviation parameter comprising at least one of a first deviation ratio and a first deviation value;
determining the electrical property parameter with the largest parameter value among the plurality of second electrical property parameters as a second target parameter, and determining a second deviation parameter of each of the second electrical property parameters except the second target parameter from the second target parameter, wherein the second deviation parameter comprises at least one of a second deviation ratio and a second deviation value;
and if the first deviation parameter is larger than a preset first threshold value and the second deviation parameter is smaller than a preset second threshold value, taking the photovoltaic string corresponding to the first deviation parameter and the second deviation parameter as a fault photovoltaic string.
In an embodiment, before the step of using the pv string corresponding to the first deviation parameter and the second deviation parameter as the faulty pv string if the first deviation parameter is greater than a preset first threshold and the second deviation parameter is less than a preset second threshold, the step of determining the faulty pv string according to the first electrical performance parameter and the second electrical performance parameter further includes:
acquiring the preset first threshold corresponding to a first parameter interval in which the first target parameter is located;
and acquiring the preset second threshold corresponding to the second parameter interval in which the second target parameter is located.
In an embodiment, before the step of obtaining the preset first threshold corresponding to the first parameter interval in which the first target parameter is located, the method further includes:
acquiring illumination amplitude information;
determining a plurality of parameter intervals according to the illumination amplitude information;
determining the first parameter interval in a plurality of parameter intervals according to the first target parameter;
and determining the second parameter interval in a plurality of parameter intervals according to the second target parameter.
In an embodiment, after the step of obtaining the voltage value of the MPPT unit, the method further includes:
if the voltage value of the MPPT unit is smaller than or equal to a first preset voltage value, reducing the power limit value of the inverter;
and returning to the step of acquiring the voltage value of the MPPT unit.
In an embodiment, after the step of obtaining the voltage value of the MPPT unit, the method further includes:
acquiring historical voltage data of the MPPT unit;
determining the voltage change rate of the MPPT unit according to the historical voltage data;
and if the voltage change rate of the MPPT unit meets a preset range, determining the voltage upper limit value of the MPPT unit as a second preset voltage value in the historical voltage data.
In an embodiment, after the step of obtaining the voltage value of the MPPT unit, the method further includes:
and determining the voltage value of the MPPT unit under the limited power according to the second preset voltage value, and taking the voltage value under the limited power as a first preset voltage value.
In an embodiment, after the step of determining the faulty photovoltaic string according to the first electrical performance parameter and the second electrical performance parameter, the method further includes:
and generating fault alarm information according to the fault photovoltaic group string and sending the fault alarm information to a preset terminal.
In order to achieve the above object, the present invention further provides a device for detecting a fault of a photovoltaic string, where the device for detecting a fault of a photovoltaic string includes:
the acquisition module is used for acquiring the voltage value of the MPPT unit;
a first analysis module for determining a first electrical performance parameter of each photovoltaic string when a voltage value of the MPPT unit is greater than a first preset voltage value, the first electrical performance parameter including at least one of a first current and a first voltage;
the second analysis module is used for determining a second electrical performance parameter of each photovoltaic group string when the voltage value of the MPPT unit is smaller than a second preset voltage value, wherein the second preset voltage value is smaller than the first preset voltage value, and the second electrical performance parameter comprises at least one of a second current and a second voltage;
a determination module to determine a faulty photovoltaic string based on the first electrical performance parameter and the second electrical performance parameter.
In order to achieve the above object, the present invention further provides a fault detection device for a pv string, which includes a memory, a processor, and a fault detection program for a pv string stored in the memory and executable on the processor, wherein the fault detection program for a pv string, when executed by the processor, implements the steps of the fault detection method for a pv string as described above.
To achieve the above object, the present invention further provides a computer-readable storage medium storing a fault detection program of a pv string, which when executed by a processor, implements the steps of the fault detection method of the pv string as described above.
The invention provides a fault detection method, a fault detection device, equipment and a computer-readable storage medium for a photovoltaic string, which are used for acquiring a voltage value of an MPPT unit; when the voltage value of the MPPT unit is larger than a first preset voltage value, determining a first electrical performance parameter of each photovoltaic string, wherein the first electrical performance parameter comprises at least one of a first current and a first voltage; when the voltage value of the MPPT unit is smaller than a second preset voltage value, determining a second electrical performance parameter of each photovoltaic string, wherein the second preset voltage value is smaller than the first preset voltage value, and the second electrical performance parameter comprises at least one of second current and second voltage; and determining the faulty photovoltaic string according to the first electrical performance parameter and the second electrical performance parameter. The first electrical performance parameter and the second electrical performance parameter of each photovoltaic string are determined according to the voltage value of the MPPT unit, the fault photovoltaic string is determined according to the first electrical performance parameter and the second electrical performance parameter, an inverter for IV characteristic scanning is not needed, the accuracy of fault detection of the fault photovoltaic string is guaranteed, and meanwhile the cost of fault detection of the photovoltaic string is saved.
Drawings
Fig. 1 is a schematic hardware structure diagram of a fault detection apparatus for a photovoltaic string according to an embodiment of the present invention;
fig. 2 is a schematic flow chart of a fault detection method for a photovoltaic string according to a first embodiment of the present invention;
FIG. 3 is a schematic diagram of current values of a normal photovoltaic string and a faulty photovoltaic string in the method for detecting a fault in a photovoltaic string according to the present invention;
fig. 4 is a detailed flowchart of step S40 of the method for detecting a fault in a photovoltaic string according to the second embodiment of the present invention;
fig. 5 is a detailed flowchart of step S40 of the method for detecting a fault in a photovoltaic string according to the third embodiment of the present invention;
fig. 6 is a schematic flow chart of a method for detecting a fault in a photovoltaic string according to a fourth embodiment of the present invention;
fig. 7 is a schematic flow chart of a fifth embodiment of the method for detecting a fault in a photovoltaic string according to the present invention;
fig. 8 is a schematic structural diagram of a fault detection device for a photovoltaic string according to 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 main solution of the embodiment of the invention is as follows: acquiring a voltage value of the MPPT unit; when the voltage value of the MPPT unit is larger than a first preset voltage value, determining a first electrical performance parameter of each photovoltaic string, wherein the first electrical performance parameter comprises at least one of a first current and a first voltage; when the voltage value of the MPPT unit is smaller than a second preset voltage value, determining a second electrical performance parameter of each photovoltaic string, wherein the second preset voltage value is smaller than the first preset voltage value, and the second electrical performance parameter comprises at least one of a second current and a second voltage; and determining a faulty photovoltaic string according to the first electrical performance parameter and the second electrical performance parameter.
The first electrical performance parameter and the second electrical performance parameter of each photovoltaic string are determined according to the voltage value of the MPPT unit, the fault photovoltaic string is determined according to the first electrical performance parameter and the second electrical performance parameter, an inverter for IV characteristic scanning is not needed, the accuracy of fault detection of the fault photovoltaic string is guaranteed, and meanwhile the cost of fault detection of the photovoltaic string is saved.
As an implementation, the fault detection device based on the photovoltaic string may be as shown in fig. 1.
The embodiment of the invention relates to a fault detection device of a photovoltaic string, which comprises: a processor 101, e.g. a CPU, a memory 102, a communication bus 103. Wherein a communication bus 103 is used for enabling the connection communication between these components.
The memory 102 may be a high-speed RAM memory or a non-volatile memory (e.g., a disk memory). As shown in fig. 1, a fault detection program of a photovoltaic string may be included in a memory 102 as a computer-readable storage medium; and the processor 101 may be configured to invoke a fault detection program for the string of photovoltaic strings stored in the memory 102 and perform the following operations:
acquiring a voltage value of the MPPT unit;
when the voltage value of the MPPT unit is larger than a first preset voltage value, determining a first electrical performance parameter of each photovoltaic string, wherein the first electrical performance parameter comprises at least one of a first current and a first voltage;
when the voltage value of the MPPT unit is smaller than a second preset voltage value, determining a second electrical performance parameter of each photovoltaic string, wherein the second preset voltage value is smaller than the first preset voltage value, and the second electrical performance parameter comprises at least one of a second current and a second voltage;
and determining a faulty photovoltaic string according to the first electrical performance parameter and the second electrical performance parameter.
In an embodiment, the processor 101 may be configured to invoke a fault detection program for the string of photovoltaic strings stored in the memory 102 and perform the following operations:
determining an electrical property parameter of the plurality of first electrical property parameters having a largest parameter value as a first target parameter, determining a first deviation parameter of each of the first electrical property parameters other than the first target parameter from the first target parameter, the first deviation parameter comprising at least one of a first deviation ratio and a first deviation value;
determining the electrical property parameter with the largest parameter value among the plurality of second electrical property parameters as a second target parameter, and determining a second deviation parameter of each of the second electrical property parameters except the second target parameter from the second target parameter, wherein the second deviation parameter comprises at least one of a second deviation ratio and a second deviation value;
and if the first deviation parameter is larger than a preset first threshold value and the second deviation parameter is smaller than a preset second threshold value, taking the photovoltaic string corresponding to the first deviation parameter and the second deviation parameter as a fault photovoltaic string.
In an embodiment, the processor 101 may be configured to invoke a fault detection program for the string of photovoltaic strings stored in the memory 102 and perform the following operations:
acquiring the preset first threshold corresponding to a first parameter interval in which the first target parameter is located;
and acquiring the preset second threshold corresponding to the second parameter interval in which the second target parameter is located.
In an embodiment, the processor 101 may be configured to invoke a fault detection program for the string of photovoltaic strings stored in the memory 102 and perform the following operations:
acquiring illumination amplitude information;
determining a plurality of parameter intervals according to the illumination amplitude information;
determining the first parameter interval in a plurality of parameter intervals according to the first target parameter;
and determining the second parameter interval in a plurality of parameter intervals according to the second target parameter.
In an embodiment, the processor 101 may be configured to invoke a fault detection program for the string of photovoltaic strings stored in the memory 102 and perform the following operations:
if the voltage value of the MPPT unit is smaller than or equal to a first preset voltage value, reducing the power limit value of the inverter;
and returning to the step of acquiring the voltage value of the MPPT unit.
In an embodiment, the processor 101 may be configured to invoke a fault detection program for the string of photovoltaic strings stored in the memory 102 and perform the following operations:
acquiring historical voltage data of the MPPT unit;
determining the voltage change rate of the MPPT unit according to the historical voltage data;
and if the voltage change rate of the MPPT unit meets a preset range, determining the voltage upper limit value of the MPPT unit as a second preset voltage value in the historical voltage data.
In an embodiment, the processor 101 may be configured to invoke a fault detection program for the string of photovoltaic strings stored in the memory 102 and perform the following operations:
and determining the voltage value of the MPPT unit under the limited power according to the second preset voltage value, and taking the voltage value under the limited power as a first preset voltage value.
Based on the hardware architecture of the fault detection device of the photovoltaic string, the embodiment of the fault detection method of the photovoltaic string is provided.
In an embodiment, the processor 101 may be configured to invoke a fault detection program for the string of photovoltaic strings stored in the memory 102 and perform the following operations:
and generating fault alarm information according to the fault photovoltaic group string and sending the fault alarm information to a preset terminal.
Referring to fig. 2, fig. 2 is a first embodiment of the method for detecting a fault of a photovoltaic string according to the present invention, and the method for detecting a fault of a photovoltaic string includes the following steps:
in step S10, a voltage value of the MPPT unit is acquired.
Specifically, the voltage value of the MPPT unit may be a voltage value measured at the current time, or may be each voltage value in the history voltage data. Therefore, the voltage value of the MPPT unit at the current moment can be obtained by measuring a voltmeter connected with the MPPT unit in parallel, and the voltage value of the MPPT unit at any moment can also be obtained by historical voltage data.
Step S20, when the voltage value of the MPPT unit is greater than a first preset voltage value, determining a first electrical performance parameter of each photovoltaic string, where the first electrical performance parameter includes at least one of a first current and a first voltage.
Specifically, the first preset voltage value is a minimum voltage value of the MPPT unit under a power limit condition, the first electrical property parameter is a characteristic parameter of the photovoltaic string, and the first electrical property parameter at least includes one of a current value and a voltage value of the photovoltaic string, that is, one of a first current and a first voltage.
Step S30, when the voltage value of the MPPT unit is smaller than a second preset voltage value, determining a second electrical performance parameter of each photovoltaic string, where the second preset voltage value is smaller than the first preset voltage value, and the second electrical performance parameter includes at least one of a second current and a second voltage.
Specifically, the second preset voltage value is a maximum voltage value of the MPPT unit under an unlimited power condition, and the first preset voltage value is greater than the second preset voltage value. The second electrical property parameter is a characteristic parameter of the photovoltaic string, and the second electrical property parameter includes at least one of a current value and a voltage value of the photovoltaic string, i.e., one of a second current and a second voltage.
And step S40, determining a fault photovoltaic string according to the first electrical performance parameter and the second electrical performance parameter.
Specifically, a faulty or normal photovoltaic string of the plurality of photovoltaic strings may be determined based on the first electrical performance parameter and the second electrical performance parameter. The first electrical property parameter and the second electrical property parameter are characteristic parameters of the photovoltaic string in different voltage ranges, and the photovoltaic string corresponding to the first electrical property parameter and the second electrical property parameter can be determined to be a faulty photovoltaic string under the condition that the first electrical property parameter meets a preset threshold corresponding to the voltage range where the first electrical property parameter is located and the second electrical property parameter meets a preset threshold corresponding to the voltage range where the second electrical property parameter is located. Illustratively, as shown in fig. 3, a and b are current values of a normal pv string, c is a current value of a failed pv string, and d is a voltage value of an MPPT unit. Under the condition of limited power, when the voltage value of the MPPT unit is greater than a first preset voltage, the current value of the fault photovoltaic string is far smaller than that of the normal photovoltaic string. And when the voltage value of the MPPT unit is smaller than the second preset voltage, the difference value between the current value of the normal photovoltaic string and the current value of the fault photovoltaic string is smaller. The current value of the photovoltaic string can be measured according to the adjustment of the voltage value of the MPPT unit under the limited power. Under the condition of power limitation, the difference value between the normal photovoltaic string and the fault photovoltaic string is different from the difference value between the normal photovoltaic string and the fault photovoltaic string, and the current values of the normal photovoltaic string and the fault photovoltaic string are greatly different under the condition of power limitation, so that the fault photovoltaic string is screened out.
After the fault photovoltaic group string is determined, fault warning information is generated according to the fault photovoltaic group string and is sent to a preset terminal, and therefore maintenance personnel are informed to overhaul and maintain.
In the technical scheme of this embodiment, whether the photovoltaic string corresponding to the first electrical performance parameter and the second electrical performance parameter is a faulty photovoltaic string is determined by calculating a first deviation ratio and a first deviation value between the first electrical performance parameter and the first target parameter at different voltages under the limited power and a first deviation ratio and a first deviation value between the second electrical performance parameter and the first target parameter at different voltages, and under the condition of limited power, analysis on the faulty photovoltaic string is more accurate than under the condition of unlimited power. And whether the photovoltaic array string has faults is diagnosed, software is not upgraded or an inverter with an IV scanning function is installed, and only historical voltage data needs to be measured, so that the cost is saved.
Referring to fig. 4, fig. 4 is a second embodiment of the method for detecting a fault of a photovoltaic string according to the present invention, and based on the first embodiment, the step S40 includes:
step S41, determining the electrical property parameter with the largest parameter value among the plurality of first electrical property parameters as a first target parameter, and determining a first deviation parameter of each of the first electrical property parameters except the first target parameter from the first target parameter, the first deviation parameter including at least one of a first deviation ratio and a first deviation value.
And step S42, determining the electrical property parameter with the largest parameter value among the plurality of second electrical property parameters as a second target parameter, and determining a second deviation parameter of each of the second electrical property parameters except the second target parameter from the second target parameter, wherein the second deviation parameter comprises at least one of a second deviation ratio and a second deviation value.
Step S43, if the first deviation parameter is greater than a preset first threshold value, and the second deviation parameter is less than a preset second threshold value, the photovoltaic string corresponding to the first deviation parameter and the second deviation parameter is used as a faulty photovoltaic string.
Specifically, the first target parameter is an electrical property parameter with the largest parameter value among a plurality of first electrical property parameters at the same time, and each first electrical property parameter except the first target parameter and a first deviation parameter of the first target parameter are respectively determined, wherein the first deviation parameter comprises one of a first deviation ratio and a first deviation value. The first deviation value is a difference value between the first target parameter and the first electrical property parameter, and the first deviation ratio is a ratio of the first deviation value to the first target parameter. The first deviation parameter is used to measure the degree of difference between each of the first electrical property parameters and the first target parameter.
The second target parameter is the electrical property parameter with the largest parameter value in the plurality of second electrical property parameters at the same time, and each second electrical property parameter except the second target parameter and a second deviation parameter of the second target parameter are respectively determined, wherein the second deviation parameter comprises one of a second deviation ratio and a second deviation value. The second deviation value is a difference between the second target parameter and the second electrical property parameter, and the second deviation ratio is a ratio of the second deviation value to the second target parameter. The second deviation parameter is used to measure the degree of difference between each of the second electrical property parameters and the second target parameter.
If the first deviation parameter is greater than the preset first threshold, Ix > a and/or Ix > b may be provided, where Ix is the first deviation ratio, Ix is the first deviation value, both the first deviation ratio and the first deviation value are greater than or equal to 0, and the second deviation parameter is less than the preset second threshold, Iz < c and/or Iz < d may be provided, where Iz is the second deviation ratio, Iz is the second deviation value, both the second deviation ratio and the second deviation value are greater than or equal to 0. The photovoltaic string corresponding to the first deviation parameter and the second deviation parameter can be determined as a faulty photovoltaic string.
If the first deviation parameter is smaller than the preset first threshold, Ix may be < a and/or Ix < b, where Ix is the first deviation ratio and Ix is the first deviation value. The second deviation parameter is smaller than a preset second threshold, and may be Iz < c and/or Iz < d, where Iz is a second deviation ratio and Iz is a second deviation value. It may be determined that the pv strings corresponding to the first deviation parameter and the second deviation parameter are normal pv strings.
If the first deviation parameter is greater than the preset first threshold, it may be Ix > a and/or Ix > b, where Ix is the first deviation ratio and Ix is the first deviation value. The second deviation parameter is larger than a preset second threshold value, and may be Iz > c and/or Iz > d, where Iz is a second deviation ratio and Iz is a second deviation value. It may be determined that the pv strings corresponding to the first deviation parameter and the second deviation parameter are normal pv strings.
If the first deviation parameter is smaller than the preset first threshold, Ix may be < a and/or Ix < b, where Ix is the first deviation ratio and Ix is the first deviation value. The second deviation parameter is larger than a preset second threshold value, and may be Iz > c and/or Iz > d, where Iz is a second deviation ratio and Iz is a second deviation value. It can also be determined that the pv strings corresponding to the first deviation parameter and the second deviation parameter are normal pv strings.
In the technical scheme of this embodiment, through carrying out the calculation of deviation proportion and deviation value to first electrical property parameter and second electrical property parameter to judge the deviation proportion and the deviation value that obtain, can carry out the troubleshooting to the fault condition of photovoltaic group cluster, obtain trouble photovoltaic group cluster, the maintenance and the maintenance of follow-up photovoltaic system of being convenient for.
Referring to fig. 5, fig. 5 is a third embodiment of the method for detecting a fault of a photovoltaic string according to the present invention, and based on the first or second embodiment, before step S43, the step S40 further includes:
step S44, acquiring the preset first threshold corresponding to the first parameter interval in which the first target parameter is located;
step S45, obtaining the preset second threshold corresponding to the second parameter interval in which the second target parameter is located.
Specifically, under different weather conditions or the shielding condition, the illumination amplitude is different, so that the electrical performance parameters are different in size, and the single threshold value cannot accurately judge the fault condition of the photovoltaic module under the condition that the first electrical performance parameter and the second electrical performance parameter are larger or smaller, so that different threshold values need to be set to judge the first deviation parameter and the second deviation parameter, and the analysis accuracy is improved.
Acquiring illumination amplitude information; determining a plurality of parameter intervals according to the illumination amplitude information; determining the first parameter interval in a plurality of parameter intervals according to the first target parameter; and determining the second parameter interval in a plurality of parameter intervals according to the second target parameter.
The plurality of parameter intervals may be n intervals (n is a natural number greater than or equal to 1) divided by size from 1 to n, and respectively correspond to n different thresholds, for example, if the first target parameter belongs to the nth interval, the first threshold corresponding to the first target parameter is An and An, and it is determined whether a first deviation ratio in the first deviation parameter of the first electrical performance parameter of each photovoltaic string satisfies Ix > An, and whether the first deviation value satisfies Ix > An. And if the second target parameter belongs to the nth interval, the second threshold corresponding to the second target parameter is Bn and Bn, and whether a first deviation proportion in the second deviation parameters of the second electrical performance parameters of each photovoltaic group string meets Iz < Bn or not and whether the first deviation value meets Iz < Bn or not are judged, wherein An is greater than Bn and An is greater than Bn.
In the technical scheme of this embodiment, the first electrical property parameter and the second electrical property parameter of the photovoltaic string are determined by determining the first threshold and the second threshold of the multi-stage parameter interval, so as to obtain a faulty photovoltaic string, thereby preventing the situation that the single threshold cannot be determined due to the small or large parameter values of the first electrical property parameter and the second electrical property parameter, and improving the accuracy of fault analysis.
Referring to fig. 6, fig. 6 is a fourth embodiment of the method for detecting a fault of a photovoltaic string according to the present invention, and based on any one of the first to third embodiments, after step S10, the method further includes:
step S50, if the voltage value of the MPPT unit is less than or equal to a first preset voltage value, reducing the power limit of the inverter;
in step S60, the procedure of acquiring the voltage value of the MPPT unit is returned to.
Specifically, the voltage values of the MPPT units larger than a first preset voltage value are searched in the historical voltage data, and if the voltage values of all the MPPT units are smaller than or equal to the first preset voltage value, the power limit value of the inverter is reduced, so that the voltage value of the MPPT unit is larger than the first preset voltage value. And then returning to the step of acquiring the voltage value of the MPPT unit.
In the technical scheme of this embodiment, the power limit of the inverter is continuously adjusted, so that the voltage value of the MPPT unit is greater than a first preset voltage value, and thus the first electrical property parameter is obtained to perform the subsequent steps.
Referring to fig. 7, fig. 7 is a fifth embodiment of the method for detecting a fault of a photovoltaic string according to the present invention, and based on any one of the first to fourth embodiments, after step S10, the method further includes:
step S70, acquiring historical voltage data of the MPPT unit;
step S80, determining the voltage change rate of the MPPT unit according to the historical voltage data;
step S90, if the voltage change rate of the MPPT unit satisfies a preset range, determining the upper limit of the MPPT unit voltage in the historical voltage data as a second preset voltage value.
Specifically, the historical voltage data is voltage data under the condition of unlimited power, the voltage change rate of the MPPT unit is determined according to the time and the voltage value of the historical voltage data, when the voltage change rate of the MPPT unit meets a preset range, the voltage upper limit value of the MPPT unit is determined, and if the voltage change rate of the MPPT unit does not belong to a normal range, namely, the voltage change rate is large, the determination of the voltage upper limit value of the MPPT unit has an error.
After step S90, the method further includes:
and determining the voltage value of the MPPT unit under the limited power according to the second preset voltage value, and taking the voltage value under the limited power as a first preset voltage value.
The voltage value of the MPPT unit under the power limit condition can be obtained by adding a preset voltage value to the second preset voltage value, so that the first preset voltage value is obtained.
In the technical scheme of this embodiment, a second preset voltage value is determined according to the historical voltage data, and a first preset voltage value is determined according to the second preset voltage value, so that the first electrical property parameter and the second electrical property parameter are obtained, and the subsequent steps are performed.
Referring to fig. 8, the present invention provides a fault detection apparatus of a photovoltaic string, including:
an obtaining module 100, configured to obtain a voltage value of the MPPT unit;
a first analysis module 200 for determining a first electrical performance parameter of each photovoltaic string when the voltage value of the MPPT unit is greater than a first preset voltage value, the first electrical performance parameter including at least one of a first current and a first voltage;
a second analysis module 300, configured to determine a second electrical performance parameter of each photovoltaic string when the voltage value of the MPPT unit is smaller than a second preset voltage value, where the second preset voltage value is smaller than the first preset voltage value, and the second electrical performance parameter includes at least one of a second current and a second voltage;
a determining module 400 for determining a faulty photovoltaic string based on the first electrical performance parameter and the second electrical performance parameter.
The invention further provides a fault detection device for a photovoltaic string, which includes a memory, a processor, and a fault detection program for a photovoltaic string stored in the memory and executable on the processor, wherein the fault detection program for a photovoltaic string, when executed by the processor, implements the steps of the fault detection method for a photovoltaic string according to the above embodiment.
The present invention also provides a computer-readable storage medium storing a fault detection program of a pv string, which when executed by a processor implements the steps of the method for detecting a fault in a pv string as described in the above embodiments.
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.
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 apparatus 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 apparatus. 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 apparatus that comprises the element.
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 computer-readable storage medium (such as ROM/RAM, magnetic disk, optical disk) as described above, and includes several instructions for enabling a terminal device (such as a mobile phone, a computer, a server, an air conditioner, or a network 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 not intended to limit the scope of the present invention, and all modifications of equivalent structures and equivalent processes, which are made by using the contents of the present specification and the accompanying drawings, or directly or indirectly applied to other related technical fields, are included in the scope of the present invention.
Claims (11)
1. A fault detection method of a photovoltaic string is characterized in that the fault detection method of the photovoltaic string is applied to a photovoltaic power generation system, the photovoltaic power generation system comprises a Maximum Power Point Tracking (MPPT) unit and a plurality of photovoltaic strings connected in parallel, the plurality of photovoltaic strings are connected in series with the MPPT unit after being connected in parallel, and the fault detection method of the photovoltaic strings comprises the following steps:
acquiring a voltage value of the MPPT unit;
when the voltage value of the MPPT unit is larger than a first preset voltage value, determining a first electrical performance parameter of each photovoltaic string, wherein the first electrical performance parameter comprises at least one of a first current and a first voltage;
when the voltage value of the MPPT unit is smaller than a second preset voltage value, determining a second electrical performance parameter of each photovoltaic string, wherein the second preset voltage value is smaller than the first preset voltage value, and the second electrical performance parameter comprises at least one of a second current and a second voltage;
and determining a faulty photovoltaic string according to the first electrical performance parameter and the second electrical performance parameter.
2. The method of fault detection of a photovoltaic string of claim 1, wherein said step of determining a faulty photovoltaic string based on said first electrical property parameter and said second electrical property parameter further comprises:
determining an electrical property parameter of the plurality of first electrical property parameters having a largest parameter value as a first target parameter, determining a first deviation parameter of each of the first electrical property parameters other than the first target parameter from the first target parameter, the first deviation parameter comprising at least one of a first deviation ratio and a first deviation value;
determining the electrical property parameter with the largest parameter value among the plurality of second electrical property parameters as a second target parameter, and determining a second deviation parameter of each of the second electrical property parameters except the second target parameter from the second target parameter, wherein the second deviation parameter comprises at least one of a second deviation ratio and a second deviation value;
and if the first deviation parameter is larger than a preset first threshold value and the second deviation parameter is smaller than a preset second threshold value, taking the photovoltaic string corresponding to the first deviation parameter and the second deviation parameter as a fault photovoltaic string.
3. The method according to claim 2, wherein, before the step of using the pv string corresponding to the first deviation parameter and the second deviation parameter as the faulty pv string if the first deviation parameter is greater than a preset first threshold and the second deviation parameter is less than a preset second threshold, the step of determining the faulty pv string according to the first electrical property parameter and the second electrical property parameter further comprises:
acquiring the preset first threshold corresponding to a first parameter interval in which the first target parameter is located;
and acquiring the preset second threshold corresponding to the second parameter interval in which the second target parameter is located.
4. The method for detecting faults of photovoltaic strings according to claim 3, wherein before the step of obtaining the preset first threshold corresponding to the first parameter interval in which the first target parameter is located, the method further comprises:
acquiring illumination amplitude information;
determining a plurality of parameter intervals according to the illumination amplitude information;
determining the first parameter interval in a plurality of parameter intervals according to the first target parameter;
and determining the second parameter interval in a plurality of parameter intervals according to the second target parameter.
5. The method for detecting faults in strings of photovoltaic cells according to claim 1, wherein the step of obtaining the voltage value of the MPPT unit is followed by further comprising:
if the voltage value of the MPPT unit is smaller than or equal to a first preset voltage value, reducing the power limit value of the inverter;
and returning to the step of acquiring the voltage value of the MPPT unit.
6. The method for detecting faults in strings of photovoltaic cells according to claim 1, wherein the step of obtaining the voltage value of the MPPT unit is followed by further comprising:
acquiring historical voltage data of the MPPT unit;
determining the voltage change rate of the MPPT unit according to the historical voltage data;
and if the voltage change rate of the MPPT unit meets a preset range, determining the voltage upper limit value of the MPPT unit as a second preset voltage value in the historical voltage data.
7. The method for detecting faults in strings of photovoltaic cells according to claim 1, wherein the step of obtaining the voltage value of the MPPT unit is followed by further comprising:
and determining the voltage value of the MPPT unit under the limited power according to the second preset voltage value, and taking the voltage value under the limited power as a first preset voltage value.
8. The method of fault detection of a photovoltaic string as claimed in claims 1 to 7, wherein after said step of determining a faulty photovoltaic string based on said first electrical property parameter and said second electrical property parameter, further comprising:
and generating fault alarm information according to the fault photovoltaic group string and sending the fault alarm information to a preset terminal.
9. A fault detection device for a photovoltaic string, the fault detection device comprising:
the acquisition module is used for acquiring the voltage value of the MPPT unit;
a first analysis module for determining a first electrical performance parameter of each photovoltaic string when a voltage value of the MPPT unit is greater than a first preset voltage value, the first electrical performance parameter including at least one of a first current and a first voltage;
the second analysis module is used for determining a second electrical performance parameter of each photovoltaic group string when the voltage value of the MPPT unit is smaller than a second preset voltage value, wherein the second preset voltage value is smaller than the first preset voltage value, and the second electrical performance parameter comprises at least one of a second current and a second voltage;
a determination module to determine a faulty photovoltaic string based on the first electrical performance parameter and the second electrical performance parameter.
10. A fault detection device of a string of photovoltaic groups, characterized in that it comprises a memory, a processor and a fault detection program of a string of photovoltaic groups stored in said memory and executable on said processor, said fault detection program of a string of photovoltaic groups, when executed by said processor, implementing the steps of the fault detection method of a string of photovoltaic groups according to any one of claims 1 to 8.
11. A computer-readable storage medium, characterized in that the computer-readable storage medium stores a fault detection program of a photovoltaic group string, which when executed by a processor implements the steps of the fault detection method of a photovoltaic group string according to any one of claims 1 to 8.
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| CN113792088A (en) * | 2021-09-10 | 2021-12-14 | 阳光电源股份有限公司 | Fault detection method and device for photovoltaic string and storage medium |
Citations (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN108055002A (en) * | 2017-12-14 | 2018-05-18 | 艾思玛新能源技术（上海）有限公司苏州高新区分公司 | A kind of photovoltaic string formation monitoring method and system |
| WO2020087128A1 (en) * | 2018-10-31 | 2020-05-07 | The University Of Queensland | Solar farm fault detection and diagnosis |
-
2020
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Patent Citations (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN108055002A (en) * | 2017-12-14 | 2018-05-18 | 艾思玛新能源技术（上海）有限公司苏州高新区分公司 | A kind of photovoltaic string formation monitoring method and system |
| WO2020087128A1 (en) * | 2018-10-31 | 2020-05-07 | The University Of Queensland | Solar farm fault detection and diagnosis |
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN113792088A (en) * | 2021-09-10 | 2021-12-14 | 阳光电源股份有限公司 | Fault detection method and device for photovoltaic string and storage medium |
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