A method and system for detecting the backsheet temperature of a photovoltaic module

Abstract

This invention discloses a method and system for detecting the backsheet temperature of photovoltaic modules, relating to the field of photovoltaic operation monitoring technology. The method includes: calculating local temperature rise values ​​based on an optical fiber thermal zone address chain and marking trusted optical fiber clips; acquiring solar irradiance, ambient wind speed, dust accumulation, module voltage, and module current, and performing operational condition correction on the local temperature rise values ​​to obtain operational condition-corrected temperature rise values; calculating the temperature rise response difference, unit irradiance temperature rise response, and residual temperature rise based on the operational condition-corrected temperature rise values, and calculating the comprehensive score of the thermal zone response and the output power deviation; using the comprehensive score of the thermal zone response and the output power deviation to screen for anomalies in the corresponding thermal zones, obtaining thermoelectrically correlated abnormal thermal zones; this invention solves the problem of difficulty in correlating and locating local thermal anomalies and electrical output anomalies on the backsheet by constructing an optical fiber thermal zone address chain.

Description

Technical Field

[0001] This invention relates to the field of photovoltaic operation monitoring technology, and in particular to a method and system for detecting the backsheet temperature of photovoltaic modules. Background Technology

[0002] With the increasing scale of photovoltaic power plant construction and the growing demand for refined operation and maintenance of photovoltaic modules, the backsheet temperature detection of photovoltaic modules has gradually evolved from manual inspection, infrared thermal imaging, and a small number of point temperature sensors to a comprehensive online monitoring method that combines distributed fiber optic temperature measurement, module electrical parameter acquisition, and environmental condition monitoring. Related methods typically assess the module's thermal state by collecting data such as backsheet temperature, solar irradiance, ambient temperature, wind speed, and module output power, and use this data to help identify risks such as hot spots, wiring abnormalities, dust accumulation due to shading, or localized aging.

[0003] Existing methods still have shortcomings. First, conventional temperature detection lacks a correlation and localization mechanism, making it difficult to reach a consistent judgment between local thermal anomalies and electrical performance deviations. Second, backplane temperature measurement results are easily affected by various factors. Evaluating the thermal status of components based solely on single-point or average temperatures can easily mask local high-risk hot areas, reducing the targeted nature of operation and maintenance. Summary of the Invention

[0004] In view of the aforementioned existing problems, the present invention is proposed.

[0005] Therefore, this invention provides a method for detecting the backsheet temperature of photovoltaic modules to solve the problem of difficulty in correlating and locating local thermal anomalies and electrical output anomalies on the backsheet.

[0006] To solve the above-mentioned technical problems, the present invention provides the following technical solution: In a first aspect, the present invention provides a method for detecting the backsheet temperature of a photovoltaic module, comprising: Fiber optic clips are installed on the backplane of photovoltaic modules. The sensing fiber segment, isolation fiber segment, backplane coordinates, hot zone and corresponding substring number of each fiber optic clip are associated to form a fiber optic hot zone address chain. Calculate the local temperature rise value based on the fiber optic hot zone address chain and mark the trusted fiber clips; The system acquires solar irradiance, ambient wind speed, dust accumulation, module voltage, and module current, and performs operating condition correction on the local temperature rise to obtain the operating condition corrected temperature rise value. The temperature rise response difference, unit irradiation temperature rise response and temperature rise residual are calculated based on the temperature rise value corrected under operating conditions. The comprehensive score of the hot zone response and the output power deviation are also calculated. The hot zone response comprehensive score and output power deviation are used to screen the hot zones for anomalies and obtain the thermoelectric correlation abnormal hot zones. A base contribution ratio is set for the hot zone of each trusted fiber clip. The base contribution ratio is adjusted based on the abnormal hot zone of thermoelectric correlation to obtain the adjusted contribution ratio. The backplane representative temperature and thermal risk index are calculated based on the adjusted contribution ratio, and a closed-loop record of the component thermal state is established.

[0007] In a preferred embodiment of the photovoltaic module backsheet temperature detection method of the present invention, the amount of dust accumulation is obtained by collecting the light transmittance of a clean reference sheet and the light transmittance of a dust accumulation sampling sheet and calculating them.

[0008] As a preferred embodiment of the photovoltaic module backsheet temperature detection method of the present invention, the specific steps of calculating the local temperature rise value based on the optical fiber thermal zone address chain and marking the trusted optical fiber clip are as follows: According to the fiber optic thermal zone address chain, read the backplane contact temperature corresponding to the sensing fiber segment in each fiber clip and the local ambient temperature corresponding to the isolation fiber segment. The difference between the backplane contact temperature and the local ambient temperature is used as the local temperature rise value, and the reliable fiber clips are marked according to the local temperature rise value.

[0009] As a preferred embodiment of the photovoltaic module backsheet temperature detection method of the present invention, the specific steps of marking the reliable optical fiber clip based on the local temperature rise value are as follows: According to the hot zone to which each fiber clip belongs in the fiber hot zone address chain, the local temperature rise values ​​of each hot zone are arranged to obtain a local temperature rise map. The difference between adjacent local temperature rise values ​​in the local temperature rise map is calculated to obtain the temperature rise difference between adjacent values; The low temperature threshold is set based on the local ambient temperature, and the temperature rise difference threshold is set based on the historical adjacent temperature rise difference. When the local temperature rise of the fiber optic clamp is less than the low temperature threshold, and the temperature rise difference between adjacent fiber optic clamps is greater than the temperature rise difference threshold, the fiber optic clamp's bonding status is judged as loose. When the local temperature rise of the fiber clip is not less than the low temperature threshold, or the temperature rise difference between adjacent fiber clips is not greater than the temperature rise difference threshold, the fiber clip bonding status is determined to be bonded. When the fiber optic clip is judged to be properly attached, the corresponding fiber optic clip is marked as a reliable fiber optic clip. When the fiber optic clip is judged to be loose, the corresponding fiber optic clip is marked as a low-reliability fiber optic clip.

[0010] As a preferred embodiment of the photovoltaic module backsheet temperature detection method of the present invention, the specific steps of performing operating condition correction on the local temperature rise value are as follows: The actual output power of the component is calculated using component voltage and component current, the irradiance value is calculated based on solar irradiance, and the air cooling heat dissipation value is calculated based on ambient wind speed. The operating condition correction temperature rise value is calculated using the actual output power of the components, the irradiation value, the air cooling heat dissipation value, the dust accumulation amount, and the local temperature rise value.

[0011] As a preferred embodiment of the photovoltaic module backsheet temperature detection method of the present invention, the specific steps for calculating the temperature rise response difference component, the unit irradiation temperature rise response, and the residual temperature rise are as follows: Differential calculations are performed on the temperature rise values ​​corrected for adjacent operating conditions to obtain the temperature rise response difference component; The solar irradiance is differentially calculated to obtain the change in solar irradiance. The ratio of the temperature rise response difference to the change in solar irradiance is taken as the temperature rise response per unit irradiance. Calculate the average of the operating condition corrected temperature rise values ​​for all the corresponding hot zones as the base temperature rise, and use the base temperature rise and the operating condition corrected temperature rise value to calculate the residual temperature rise.

[0012] As a preferred embodiment of the photovoltaic module backsheet temperature detection method of the present invention, the specific steps of anomaly screening for the corresponding hot zone are as follows: The temperature rise response difference component, the temperature rise response amount per unit irradiation, and the temperature rise residual amount were normalized to obtain the normalized temperature rise response difference component, the normalized temperature rise response amount, and the normalized temperature rise residual amount. The sum of the normalized temperature rise response difference, the normalized temperature rise response quantity, and the normalized temperature rise residual quantity is used as the comprehensive score of the thermal zone response. The average value of the comprehensive score of the thermal response is calculated as the benchmark for the comprehensive score. Thermal areas whose comprehensive scores of thermal response are higher than the benchmark for the comprehensive score are identified as candidate abnormal thermal areas. The deviation of output power is calculated using the actual output power of the component, the amount of dust accumulation, and the irradiation effect. Candidate abnormal hot zones whose output power deviation exceeds a preset deviation threshold are identified as thermoelectric-related abnormal hot zones.

[0013] As a preferred embodiment of the photovoltaic module backsheet temperature detection method of the present invention, the calculation of the backsheet representative temperature and thermal risk index includes the following steps: The operating condition correction temperature rise value corresponding to the trusted fiber clip is taken as the trusted hot zone temperature rise value, and the backplane contact temperature corresponding to the trusted fiber clip is taken as the trusted backplane temperature. A basic contribution ratio is set for the thermal zone of each trusted fiber clip based on the thermal zone to which the trusted fiber clip belongs and the thermoelectric correlation abnormal thermal zone. The basic contribution ratio of each hot zone is evenly distributed to each trusted fiber clip to obtain the corrected contribution ratio of each trusted fiber clip. The correction contribution ratio corresponding to the thermoelectric associated abnormal hot zone is adjusted, while the correction contribution ratio corresponding to the non-thermoelectric associated abnormal hot zone remains unchanged, thus obtaining the adjusted contribution ratio. The sum of all adjustment contribution ratios is taken as the total contribution ratio, and the ratio of the adjustment contribution ratio of each trusted fiber clip to the total contribution ratio is taken as the thermal fidelity contribution ratio of each trusted fiber clip. The thermal fidelity contribution ratio of each trusted fiber clip is used as a weight to weight and sum the trusted backplane temperatures to obtain the representative backplane temperature. The highest value of the backplate contact temperature corresponding to the thermoelectric abnormal hot zone is taken as the highest abnormal backplate contact temperature. When the highest abnormal backplate contact temperature is higher than the representative temperature of the backplate, the highest abnormal backplate contact temperature is used as the thermal risk indicator. When there is no thermoelectric abnormal hot zone, the representative temperature of the backplate is used as the thermal risk indicator.

[0014] As a preferred embodiment of the photovoltaic module backsheet temperature detection method of the present invention, the specific steps for establishing a closed-loop record of the module's thermal state are as follows: The thermal status level of photovoltaic modules is classified according to the temperature represented by the backsheet, thermal risk indicators, and abnormal thermal zones associated with thermoelectricity. The fiber clip number, backplane coordinates, the corresponding hot zone and the corresponding substring number of the thermoelectric correlation abnormal hot zone are used as the hot zone positioning information. Pre-set operation and maintenance actions are assigned to photovoltaic modules based on hot zone location information and thermal status level; The preset maintenance actions, fiber optic hot zone address chain, local temperature rise value, operating condition correction temperature rise value, thermoelectric abnormal hot zone, backplane representative temperature and thermal risk indicators are merged into a closed-loop record of component thermal status.

[0015] Secondly, the present invention provides a photovoltaic module backsheet temperature detection system, comprising: The association module deploys fiber clips on the backplane of the photovoltaic module and associates the sensing fiber segment, isolation fiber segment, backplane coordinates, hot zone and corresponding substring number of each fiber clip to form a fiber hot zone address chain. The marking module calculates the local temperature rise value based on the fiber optic hot zone address chain and marks the trusted fiber clips; The calibration module acquires solar irradiance, ambient wind speed, dust accumulation, component voltage, and component current, and performs operating condition correction on the local temperature rise value to obtain the operating condition corrected temperature rise value. The screening module calculates the temperature rise response difference, unit irradiation temperature rise response, and temperature rise residue based on the operating condition corrected temperature rise value, and calculates the comprehensive score of the hot zone response and the output power deviation. It uses the comprehensive score of the hot zone response and the output power deviation to screen the hot zones for anomalies and obtain the thermoelectric correlation abnormal hot zones. The recording module sets a basic contribution ratio for the hot zone of each trusted fiber clip, adjusts the basic contribution ratio based on the abnormal hot zone of thermoelectric correlation to obtain the adjusted contribution ratio, calculates the backplane representative temperature and thermal risk index based on the adjusted contribution ratio, and establishes a closed-loop record of the component thermal state.

[0016] The beneficial effects of this invention are as follows: By constructing an optical fiber thermal zone address chain, the backplane temperature acquisition results are no longer limited to isolated measurement points, but can be mapped to specific thermal zones and electrical structure locations. This helps improve the correlation and identification accuracy between local thermal anomalies and electrical output anomalies, and solves the problem of difficulty in associating and locating local thermal anomalies and electrical output anomalies on the backplane. In addition, by calculating the local temperature rise value through the sensing fiber segment and the isolation fiber segment, the impact of loose fiber clamps or local environmental disturbances on the detection results is reduced, avoiding the masking of high-risk thermal zones by average evaluation, and improving the targeting of operation and maintenance. Attached Figure Description

[0017] To more clearly illustrate the technical solutions of the embodiments of the present invention, the drawings used in the following description of the embodiments will be briefly introduced. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0018] Figure 1 This is a flowchart of a method for detecting the backsheet temperature of a photovoltaic module.

[0019] Figure 2 This is a schematic diagram of a photovoltaic module backsheet temperature detection system.

[0020] Figure 3 This diagram illustrates the calculation of the temperature rise response difference component, the temperature rise response per unit irradiation, and the residual temperature rise.

[0021] Figure 4 A schematic diagram for generating a closed-loop record of the component's thermal state. Detailed Implementation

[0022] To make the above-mentioned objects, features and advantages of the present invention more apparent and understandable, the specific embodiments of the present invention will be described in detail below with reference to the accompanying drawings.

[0023] Many specific details are set forth in the following description in order to provide a full understanding of the invention. However, the invention may also be practiced in other ways different from those described herein, and those skilled in the art can make similar extensions without departing from the spirit of the invention. Therefore, the invention is not limited to the specific embodiments disclosed below.

[0024] Secondly, the term "one embodiment" or "embodiment" as used herein refers to a specific feature, structure, or characteristic that may be included in at least one implementation of the present invention. The phrase "in one embodiment" appearing in different places in this specification does not necessarily refer to the same embodiment, nor is it a single or selective embodiment that is mutually exclusive with other embodiments.

[0025] Reference Figures 1-4 As one embodiment of the present invention, this embodiment provides a method for detecting the backsheet temperature of a photovoltaic module, comprising the following steps: S1: Install fiber optic clips on the backplane of the photovoltaic module, and associate the sensing fiber segment, isolation fiber segment, backplane coordinates, hot zone and corresponding substring number of each fiber optic clip to form a fiber optic hot zone address chain.

[0026] Fiber optic clips are installed on the back panel of the photovoltaic module, so that the sensing fiber segment in each fiber optic clip is attached to the back panel of the photovoltaic module, and the isolation fiber segment in each fiber optic clip is isolated from the back panel of the photovoltaic module by a heat insulation layer.

[0027] Record the component number, fiber clip number, backplane coordinates, hot zone, corresponding substring number, sensing fiber segment position, and isolation fiber segment position for each fiber clip.

[0028] The corresponding heat zone refers to the functional temperature area where each optical fiber is clamped on the backsheet of the photovoltaic module, including the junction box affected area, the main heated area, and the edge heat exchange area.

[0029] The corresponding substring number refers to the internal electrical substring identifier of the component corresponding to the backplane coordinates of the fiber clip.

[0030] Associating the component number, fiber clip number, backplane coordinates, corresponding hot zone, sensing fiber segment position, isolation fiber segment position, and corresponding substring number with the fiber clip number yields the fiber clip association record.

[0031] The fiber optic clamp association records are sorted according to the order in which the continuous temperature measurement fiber passes through each fiber clamp to form a fiber optic thermal zone address chain.

[0032] S2: Calculate the local temperature rise value based on the fiber optic hot zone address chain and mark the trusted fiber clip.

[0033] S2.1: According to the position of the sensing fiber segment of each fiber clip in the fiber optic hot zone address chain, read the temperature sampling value of each sensing fiber segment, and calculate the average value of the temperature sampling value of each sensing fiber segment as the backplane contact temperature of each fiber clip.

[0034] According to the location of the isolated fiber segment in each fiber clip in the fiber optic hot zone address chain, the temperature sampling value of each isolated fiber segment is read, and the average value of the temperature sampling value of each isolated fiber segment is calculated as the local ambient temperature of each fiber clip.

[0035] By associating the backplane contact temperature with the local ambient temperature according to the fiber clip number in the fiber optic hot zone address chain, the fiber clip temperature record for each fiber clip is obtained.

[0036] The difference between the backplate contact temperature and the local ambient temperature in the fiber clip temperature record of each fiber clip is taken as the local temperature rise value of the hot zone to which the fiber clip belongs.

[0037] S2.2: Establish a backsheet coordinate system with the lower left corner of the photovoltaic module backsheet as the origin, and the long side and short side of the module as the first and second coordinate axes, respectively.

[0038] Mark the corresponding hot zone of the fiber clip in the backplane coordinate system to obtain the location map of the corresponding hot zone. Mark the local temperature rise value of each corresponding hot zone on the location map of the corresponding hot zone to obtain the local temperature rise map.

[0039] The absolute value of the difference in local temperature rise between two adjacent fiber clips in the local temperature rise diagram is taken as the spatial temperature rise difference, and the maximum value of the spatial temperature rise difference corresponding to each fiber clip is taken as the adjacent temperature rise difference.

[0040] The average local ambient temperature of each fiber clip at the same sampling time is taken as the average local ambient temperature.

[0041] Calculate the absolute deviation between the local ambient temperature of each fiber clip and the average local ambient temperature, and use the sum of the maximum absolute deviation and the temperature measurement accuracy value of the continuous temperature measuring fiber as the low temperature threshold.

[0042] Based on historical adjacent temperature rise differences, a percentile method is used to set the temperature rise difference threshold. For example, the historical adjacent temperature rise differences are arranged from smallest to largest, and the 95th percentile historical adjacent temperature rise difference is selected as the temperature rise difference threshold.

[0043] It should also be noted that the 95th percentile was chosen because it can cover normal adjacent temperature rise fluctuations while retaining abnormal abrupt changes as candidates for loosening or abnormal fit. A percentile greater than 95 percentile would miss some slight loosening or early fit abnormalities, while a percentile less than 95 percentile would misjudge adjacent temperature rise fluctuations under normal operating conditions as loosening.

[0044] When the local temperature rise of the fiber optic clamp is less than the low temperature threshold, and the temperature rise difference between adjacent fiber optic clamps is greater than the temperature rise difference threshold, the fiber optic clamp's bonding status is judged as loose.

[0045] When the local temperature rise of the fiber optic clamp is not less than the low temperature threshold, or the temperature rise difference between adjacent fiber optic clamps is not greater than the temperature rise difference threshold, the fiber optic clamp bonding status is determined to be bonded.

[0046] Fiber optic clips with a loose fit are marked as low-confidence fiber optic clips, while those with a properly fitted fit are marked as reliable fiber optic clips.

[0047] S3: Acquire solar irradiance, ambient wind speed, dust accumulation, module voltage, and module current, and perform operating condition correction on the local temperature rise value to obtain the operating condition corrected temperature rise value.

[0048] Collect solar irradiance, ambient wind speed, component voltage, and component current corresponding to the hot zone to which the trusted fiber clip belongs.

[0049] The light transmittance of the clean reference sheet and the light transmittance of the dust sampling sheet are collected. The difference between the light transmittance of the clean reference sheet and the light transmittance of the dust sampling sheet is taken as the change in light transmittance. The ratio of the change in light transmittance to the light transmittance of the clean reference sheet is taken as the amount of dust.

[0050] Dust accumulation refers to the degree to which dust, sand, and particulate matter deposited on the light-receiving surface of a photovoltaic module affect light transmission and reception; it is dimensionless.

[0051] The product of the component voltage and the component current is taken as the actual output power of the component.

[0052] The solar irradiance under the rated power test conditions of photovoltaic modules is used as the reference solar irradiance, and the ratio of solar irradiance to the reference solar irradiance is used as the irradiance value.

[0053] The median historical ambient wind speed is used as the baseline ambient wind speed, and the ratio of the ambient wind speed to the baseline ambient wind speed is used as the air-cooled heat dissipation value.

[0054] The rated output power of the photovoltaic modules is collected. Using the actual output power, dust accumulation, and irradiance values ​​of the modules, the electrical output state value of the thermal zone to which each reliable fiber clip belongs is calculated using the rated output power. The expression is as follows: ; in, For the first Electrical output state value of the thermal zone to which the trusted fiber clip belongs. For the first The actual output power of the components in the hot zone to which the reliable fiber clip belongs. Rated output power, For the first The irradiance value of the thermal zone to which the reliable optical fiber clip belongs. For the first When the amount of dust accumulation in the hot zone of a reliable fiber optic clip exceeds one or the denominator is zero, the electrical output status value is directly taken as one to avoid forming a negative electrical output correction.

[0055] It should also be noted that the actual output power of the module refers to the actual output power of the photovoltaic module. The actual output power of each thermal zone within the photovoltaic module is expressed by the actual output power of the corresponding photovoltaic module.

[0056] The operating condition-corrected temperature rise value for the thermal zone of each trusted fiber clip is calculated using local temperature rise, dust accumulation, irradiation, air cooling, and electrical output status values, as shown in the following expression: ; in, For the first The operating condition-corrected temperature rise value of the thermal zone to which the trusted fiber optic clip belongs, in degrees Celsius. For the first The local temperature rise value of the thermal zone to which the trusted optical fiber clip belongs, in degrees Celsius. This is the irradiation correction factor, in degrees Celsius. This is the air-cooling correction factor, in degrees Celsius. For the first The air-cooled heat dissipation value of the hot zone to which the reliable fiber optic clip belongs. This is the dust accumulation correction factor, in degrees Celsius. This is the electrical output correction factor, in degrees Celsius. Indicates the degree of weakness in electrical output. This is the index of the hot zone to which the trusted fiber clip belongs.

[0057] It should also be noted that the expression for calculating the temperature rise value under operating conditions is used to characterize the abnormal temperature rise of the hot zone to which the reliable fiber clip belongs after eliminating disturbances from solar irradiance, ambient wind speed, and dust accumulation, and combined with the degree of weak electrical output. The irradiance correction term is used to reduce the impact of normal temperature rise under high irradiance on anomaly judgment. The wind-cooling correction term is used to compensate for the underestimation of backplane temperature rise caused by ambient wind speed. The dust accumulation correction term is used to weaken the interference of conventional dust accumulation on temperature rise judgment. The electrical output correction term is used to increase the sensitivity of the hot zone to be identified as a thermoelectrically correlated abnormal hot zone when the component's electrical output is weak.

[0058] It should also be noted that the irradiance correction coefficient, wind-cooling correction coefficient, dust accumulation correction coefficient, and electrical output correction coefficient were all determined using the single-factor slope calibration method. The irradiance correction coefficient is the average slope of the local temperature rise as a function of solar irradiance; the wind-cooling correction coefficient is the average slope of the local temperature rise as a function of ambient wind speed; the dust accumulation correction coefficient is the average slope of the local temperature rise as a function of dust accumulation; and the electrical output correction coefficient is the average slope of the degree to which the local temperature rise is weaker relative to the electrical output. For example, the irradiation correction factor is set to 8 degrees Celsius, because 8 degrees Celsius can deduct the normal temperature rise caused by high irradiation. If it is greater than 8 degrees Celsius, the operating condition correction temperature rise value of the actual hot zone will be too low, and it will be easy to miss the abnormal hot zone with thermoelectric correlation. If it is less than 8 degrees Celsius, the normal hot zone under high irradiation will be misjudged as an abnormal hot zone.

[0059] The air-cooling correction factor is set to 3 degrees Celsius because 3 degrees Celsius can compensate for the low temperature reading caused by air cooling. If it is greater than 3 degrees Celsius, the temperature rise value under strong wind conditions will be too high, which is easy to cause misjudgment. If it is less than 3 degrees Celsius, the temperature rise reduction caused by air cooling will not be fully compensated, which is easy to miss the abnormal hot areas that still exist in strong wind environments.

[0060] The dust accumulation correction factor is set at 4 degrees Celsius because 4 degrees Celsius can deduct the normal shading effect caused by dust accumulation, and avoid directly identifying the normal temperature rise change caused by dust accumulation as thermal anomaly. If it is greater than 4 degrees Celsius, it will weaken the temperature rise contribution of the dust accumulation area and may miss the local hot spots induced by uneven dust accumulation. If it is less than 4 degrees Celsius, the normal shading or uneven light exposure caused by dust accumulation will still remain, and it is easy to misjudge the effect of dust accumulation as thermoelectric inconsistency.

[0061] The electrical output correction factor is set to 6 degrees Celsius because 6 degrees Celsius can improve the sensitivity when abnormal temperature rise and abnormal power generation occur simultaneously. If it is greater than 6 degrees Celsius, slight power fluctuations will be amplified into thermal risks, which can easily cause excessive alarms. If it is less than 6 degrees Celsius, the weak electrical output will not have enough impact on the temperature rise value of the operating condition correction, and it will be difficult to reflect the correlation between abnormal temperature and abnormal power generation.

[0062] S4: Calculate the temperature rise response difference, unit irradiation temperature rise response, and residual temperature rise based on the operating condition corrected temperature rise value, and calculate the comprehensive score of the hot zone response and the output power deviation. Use the comprehensive score of the hot zone response and the output power deviation to screen the hot zones for anomalies and obtain the thermoelectric correlation abnormal hot zones.

[0063] S4.1: Arrange the operating condition correction temperature rise values ​​of the hot zone to which each trusted fiber clip belongs in chronological order, calculate the difference between the operating condition correction temperature rise value at the current sampling time and the operating condition correction temperature rise value at the previous sampling time, and obtain the temperature rise response difference component of the hot zone to which each trusted fiber clip belongs.

[0064] The difference between the solar irradiance at the current sampling time and the solar irradiance at the previous sampling time is calculated to obtain the change in solar irradiance.

[0065] The ratio of the temperature rise response difference to the change in solar irradiance is used as the unit irradiance temperature rise response of the thermal zone to which each reliable fiber clip belongs. When the change in solar irradiance is zero, the unit irradiance temperature rise response is recorded as zero.

[0066] Based on historical changes in solar irradiance, a percentile method is used to set a threshold for the decrease. For example, the absolute values ​​of historical changes in solar irradiance are arranged from smallest to largest, and the absolute value of the historical change in solar irradiance at the 90th percentile is selected as the threshold for the decrease.

[0067] It should also be noted that the 90th percentile was chosen because it can identify solar irradiance decreases that exceed the normal fluctuation range, while retaining a certain degree of noise resistance. It is suitable for backplane temperature rise analysis scenarios that are more sensitive to irradiance decreases. If the percentile is greater than 90 percentile, it will miss slow or slight real irradiance decreases, while if the percentile is less than 90 percentile, it is easy to misjudge normal irradiance fluctuations as periods of solar irradiance decrease.

[0068] The sampling moment when the first change in solar irradiance is negative and the absolute value of the change in solar irradiance is less than the decreasing threshold is taken as the end moment of the decrease in solar irradiance.

[0069] The average value of the operating condition-corrected temperature rise of the thermal zone to which all reliable fiber clips belong at the moment when the solar irradiance decrease ends is calculated to obtain the reference temperature rise.

[0070] The difference between the operating condition-corrected temperature rise value and the reference temperature rise of the thermal zone to which each trusted fiber clip belongs is taken as the residual temperature rise. When the residual temperature rise is less than zero, the residual temperature rise is recorded as zero.

[0071] S4.2: The range normalization method is used to normalize the temperature rise response difference, unit irradiation temperature rise response, and temperature rise residue of each reliable fiber clip at the same sampling time, so as to obtain the normalized temperature rise response difference, normalized temperature rise response, and normalized temperature rise residue.

[0072] The sum of the normalized temperature rise response difference, normalized temperature rise response quantity, and normalized temperature rise residual quantity of the thermal zone belonging to the same trusted fiber clip is used as the comprehensive score of the thermal zone response of each trusted fiber clip.

[0073] The average of the comprehensive scores of the thermal response of all trusted fiber clips in their respective thermal zones is used as the benchmark for the comprehensive score.

[0074] The hot zones to which the trusted fiber clips belong are considered as candidate anomalous hot zones, based on their overall hot zone response score being higher than the benchmark score.

[0075] The degree of electrical output weakness corresponding to each candidate abnormal hot zone is taken as the output power deviation.

[0076] Based on the historical output power deviation, a preset deviation threshold is set using the percentile method. For example, the historical output power deviations are arranged from smallest to largest, and the historical output power deviation at the 95th percentile is selected as the preset deviation threshold.

[0077] It should also be noted that the 95th percentile was chosen because it can cover the normal output power deviation fluctuations under abnormal conditions without heat zones, while retaining abnormal deviations as objects for thermoelectric inconsistency judgment. If it is greater than the 95th percentile, early or slight thermoelectric-related abnormal heat zones will be missed, and if it is less than the 95th percentile, normal operating condition fluctuations are easily misjudged as thermoelectric-related abnormal heat zones.

[0078] Candidate abnormal hot zones whose output power deviation exceeds a preset deviation threshold are identified as thermoelectric-related abnormal hot zones.

[0079] S5: Set a basic contribution ratio for the hot zone of each trusted fiber clip, adjust the basic contribution ratio based on the abnormal hot zone of thermoelectric correlation to obtain the adjusted contribution ratio, calculate the backplane representative temperature and thermal risk index based on the adjusted contribution ratio, and establish a closed-loop record of component thermal status.

[0080] S5.1: The operating condition correction temperature rise value of the thermal zone to which the trusted fiber clip belongs is taken as the trusted thermal zone temperature rise value, and the backplane contact temperature of the thermal zone to which the trusted fiber clip belongs is taken as the trusted backplane temperature.

[0081] The basic contribution ratio of the trusted fiber clip is set according to its hot zone: the area of ​​each hot zone is collected, the sum of the areas of all hot zones is taken as the total area of ​​the hot zone, and the area of ​​each hot zone and the total area of ​​the hot zone are taken as the basic contribution ratio of each hot zone.

[0082] When no trusted fiber clip exists in any given heat exchange zone, the basic contribution ratio of the corresponding heat exchange zone is redistributed according to the basic contribution ratio of heat exchange zones with trusted fiber clips. For example, when no trusted fiber clip exists in the edge heat exchange zone, the sum of the basic contribution ratio of the main heat-receiving zone and the basic contribution ratio of the junction box-affected zone is used as the sum of the allocation ratios. The ratio of the basic contribution ratio of the main heat-receiving zone to the sum of the allocation ratios is used as the allocation ratio of the main heat-receiving zone, and the ratio of the basic contribution ratio of the junction box-affected zone to the sum of the allocation ratios is used as the allocation ratio of the junction box-affected zone. The basic contribution ratio of the edge heat exchange zone is then superimposed on the allocation ratios of the main heat-receiving zone and the junction box-affected zone.

[0083] When there is more than one trusted fiber clip within the same hot zone, the contribution ratio of the same hot zone is evenly distributed to each trusted fiber clip within the same hot zone to obtain the corrected contribution ratio of each trusted fiber clip.

[0084] The difference between the comprehensive score of the thermal response of the thermoelectric-correlated anomalous thermal zone and the comprehensive score benchmark is taken as the thermal zone anomalous deviation. The sum of all thermal zone anomalous deviations is taken as the total thermal zone anomalous deviation. The ratio of the thermal zone anomalous deviation of each thermoelectric-correlated anomalous thermal zone to the total thermal zone anomalous deviation is taken as the adjustment ratio of each thermoelectric-correlated anomalous thermal zone. The product of the adjustment ratio and the correction contribution ratio is taken as the contribution ratio increase. The contribution ratio increase is added to the correction contribution ratio of the corresponding trusted fiber clip. The correction contribution ratio of the trusted fiber clip for non-thermoelectric-correlated anomalous thermal zones remains unchanged, thus obtaining the adjustment contribution ratio.

[0085] The sum of all adjustment contribution ratios is taken as the total contribution ratio, and the ratio of the adjustment contribution ratio of each trusted fiber clip to the total contribution ratio is taken as the thermal fidelity contribution ratio of each trusted fiber clip.

[0086] The thermal fidelity contribution ratio of each trusted fiber clip is used as a weight to weight the trusted backplane temperature of each trusted fiber clip, and the weighted sum is obtained to obtain the representative temperature of the backplane.

[0087] When a thermoelectrically correlated abnormal hot zone exists, the highest value among the backplane contact temperatures of the trusted fiber clip corresponding to the thermoelectrically correlated abnormal hot zone is taken as the highest abnormal backplane contact temperature.

[0088] When the highest abnormal backplate contact temperature is higher than the representative temperature of the backplate, the highest abnormal backplate contact temperature is used as a thermal risk indicator.

[0089] When there are no abnormal hot zones associated with thermoelectricity, the temperature represented by the backplate is used as a thermal risk indicator.

[0090] S5.2: Based on historical thermal risk indicators, the percentile method is used to set them. For example, the historical thermal risk indicators are arranged from smallest to largest, and the 80th percentile, 90th percentile, and 95th percentile of the historical thermal risk indicators are selected as the first thermal risk threshold, the second thermal risk threshold, and the third thermal risk threshold, respectively.

[0091] It should also be noted that the 80th percentile was chosen as the first thermal risk threshold because it can filter out temperature rises above the normal operating temperature range. A threshold above the 80th percentile would delay the triggering of the attention level, while a threshold below the 80th percentile would make normal temperature fluctuations more likely to be classified as a concern.

[0092] The second thermal risk threshold is selected from the 90th percentile of historical thermal risk indicators because the 90th percentile can identify early warning states that deviate from the normal operating temperature range and need to be verified. If it is greater than the 90th percentile, the sensitivity of the early warning will be reduced and early anomalies will be missed. If it is less than the 90th percentile, the false triggering of the early warning level will be increased.

[0093] The third thermal risk threshold is selected from the historical thermal risk index at the 95th percentile because the 95th percentile is suitable as the trigger boundary for string load limiting or component-level shutdown verification. A threshold greater than the 95th percentile will cause high-risk handling to be triggered late, while a threshold less than the 95th percentile will cause load limiting or shutdown actions to be frequent.

[0094] When there are no abnormal hot zones related to thermoelectricity and the thermal risk index is below the first thermal risk threshold, the thermal status level of the photovoltaic module is classified as normal.

[0095] When there is an abnormal hot zone with thermoelectric correlation and the thermal risk index is lower than the first thermal risk threshold, the thermal status level of the photovoltaic module will be classified as a level of concern.

[0096] When the thermal risk index is not lower than the first thermal risk threshold but lower than the second thermal risk threshold, the thermal status level of the photovoltaic module is classified as a level of concern.

[0097] When the thermal risk index is not lower than the second thermal risk threshold but lower than the third thermal risk threshold, the thermal status level of the photovoltaic module is classified as a warning level.

[0098] When the thermal risk index is not lower than the third thermal risk threshold, the thermal status level of the photovoltaic module is classified into a treatment level.

[0099] S5.3: Use the fiber clip number, backplane coordinates, the corresponding hot zone and the corresponding substring number of the thermoelectric correlation abnormal hot zone as the hot zone positioning information.

[0100] When the thermal status level is normal, the temperature represented by the backsheet and the thermal risk indicators will be used as a thermal status indication for the photovoltaic module.

[0101] When the thermal status level is at the concern level, the hot zone location information will be used as a thermal status indicator for the photovoltaic module.

[0102] When the thermal status level is a warning level and the thermal area in the thermal area location information is the main heated area, the thermal area location information will be sent to the operation and maintenance personnel to notify them to check suspected hot spots.

[0103] When the thermal status level is a warning level and the thermal zone in the thermal zone location information is the area affected by the junction box, the thermal zone location information will be sent to the maintenance personnel to notify them to check the junction box.

[0104] When the thermal status level is at the warning level and the amount of dust accumulation in the abnormal thermal zone is higher than the average amount of dust accumulation in the thermal zone to which the trusted fiber clip belongs, the thermal zone location information will be sent to the maintenance personnel to notify them to perform targeted cleaning.

[0105] When the thermal status level is at the handling level, the hot zone location information will be sent to the operation and maintenance personnel to notify them to perform component-level shutdown verification.

[0106] The photovoltaic module thermal status alert, checking suspected hot spots, checking junction boxes, fixed-point cleaning, and module-level shutdown verification are all preset maintenance actions.

[0107] After maintenance is completed, the preset maintenance actions, fiber optic hot zone address chain, local temperature rise value, operating condition correction temperature rise value, thermoelectric abnormal hot zone, backplane representative temperature and thermal risk indicators are recorded as a closed-loop record of the component's thermal status.

[0108] This embodiment also provides a photovoltaic module backsheet temperature detection system, including: The association module deploys fiber clips on the backplane of the photovoltaic module and associates the sensing fiber segment, isolation fiber segment, backplane coordinates, hot zone and corresponding substring number of each fiber clip to form a fiber hot zone address chain. The marking module calculates the local temperature rise value based on the fiber optic hot zone address chain and marks the trusted fiber clips; The calibration module acquires solar irradiance, ambient wind speed, dust accumulation, component voltage, and component current, and performs operating condition correction on the local temperature rise value to obtain the operating condition corrected temperature rise value. The screening module calculates the temperature rise response difference, unit irradiation temperature rise response, and temperature rise residue based on the operating condition corrected temperature rise value, and calculates the comprehensive score of the hot zone response and the output power deviation. It uses the comprehensive score of the hot zone response and the output power deviation to screen the hot zones for anomalies and obtain the thermoelectric correlation abnormal hot zones. The recording module sets a basic contribution ratio for the hot zone of each trusted fiber clip, adjusts the basic contribution ratio based on the abnormal hot zone of thermoelectric correlation to obtain the adjusted contribution ratio, calculates the backplane representative temperature and thermal risk index based on the adjusted contribution ratio, and establishes a closed-loop record of the component thermal state.

[0109] This embodiment also provides a computer device applicable to the photovoltaic module backsheet temperature detection method, including: a memory and a processor; the memory is used to store computer-executable instructions, and the processor is used to execute the computer-executable instructions to implement the photovoltaic module backsheet temperature detection method proposed in the above embodiment.

[0110] The computer device can be a terminal, comprising a processor, memory, communication interface, display screen, and input devices connected via a system bus. The processor provides computing and control capabilities. The memory includes non-volatile storage media and internal memory. The non-volatile storage media stores the operating system and computer programs. The internal memory provides an environment for the operation of the operating system and computer programs stored in the non-volatile storage media. The communication interface is used for wired or wireless communication with external terminals; wireless communication can be achieved through Wi-Fi, carrier networks, NFC (Near Field Communication), or other technologies. The display screen can be an LCD screen or an e-ink screen. The input devices can be a touch layer covering the display screen, buttons, a trackball, or a touchpad on the computer device's casing, or an external keyboard, touchpad, or mouse.

[0111] This embodiment also provides a storage medium storing a computer program, which, when executed by a processor, implements the photovoltaic module backsheet temperature detection method as proposed in the above embodiments. The storage medium can be implemented by any type of volatile or non-volatile storage device or a combination thereof, such as Static Random Access Memory (SRAM), Electrically Erasable Programmable Read-Only Memory (EEPROM), Erasable Programmable Read Only Memory (EPROM), Programmable Red-Only Memory (PROM), Read-Only Memory (ROM), magnetic storage, flash memory, magnetic disk, or optical disk.

[0112] In summary, this invention constructs an optical fiber thermal zone address chain, enabling backplane temperature acquisition results to be mapped to specific thermal zones and electrical structure locations rather than isolated measurement points. This improves the accuracy of correlation identification between local thermal anomalies and electrical output anomalies, solving the problem of difficulty in correlating and locating local thermal anomalies and electrical output anomalies on the backplane. Furthermore, by calculating local temperature rise values ​​through sensing fiber segments and isolation fiber segments, the impact of loose fiber clamps or local environmental disturbances on detection results is reduced, avoiding the masking of high-risk thermal zones by averaging evaluations and improving the targeted nature of operation and maintenance.

[0113] It should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention and are not intended to limit it. Although the present invention has been described in detail with reference to preferred embodiments, those skilled in the art should understand that modifications or equivalent substitutions can be made to the technical solutions of the present invention without departing from the spirit and scope of the technical solutions of the present invention, and all such modifications or substitutions should be covered within the scope of the claims of the present invention.

Claims

1. A method for detecting the backsheet temperature of a photovoltaic module, characterized in that: include, Fiber optic clips are installed on the backplane of photovoltaic modules. The sensing fiber segment, isolation fiber segment, backplane coordinates, hot zone and corresponding substring number of each fiber optic clip are associated to form a fiber optic hot zone address chain. The local temperature rise value is calculated based on the fiber optic thermal zone address chain, and trusted fiber clips are marked. The specific steps are as follows: According to the fiber optic thermal zone address chain, read the backplane contact temperature corresponding to the sensing fiber segment in each fiber clip and the local ambient temperature corresponding to the isolation fiber segment. The difference between the backplane contact temperature and the local ambient temperature is used as the local temperature rise value, and the reliable fiber clips are marked according to the local temperature rise value. The local temperature rise values ​​of each thermal zone are arranged to obtain a local temperature rise map; The difference between adjacent local temperature rise values ​​in the local temperature rise map is calculated to obtain the temperature rise difference between adjacent values; The low temperature threshold is set based on the local ambient temperature, and the temperature rise difference threshold is set based on the historical adjacent temperature rise difference. When the local temperature rise of the fiber optic clamp is less than the low temperature threshold and the temperature rise difference between adjacent fiber optic clamps is greater than the temperature rise difference threshold, the fiber optic clamp bonding status is judged as loose. When the local temperature rise of the fiber clip is not less than the low temperature threshold, or the temperature rise difference between adjacent fiber clips is not greater than the temperature rise difference threshold, the fiber clip bonding status is determined to be bonded. When the fiber optic clip bonding status is determined to be bonded, the corresponding fiber optic clip is marked as a trusted fiber optic clip; when the fiber optic clip bonding status is determined to be loose, the corresponding fiber optic clip is marked as a low-trust fiber optic clip. The following steps are taken to obtain solar irradiance, ambient wind speed, dust accumulation, module voltage, and module current, and to perform operating condition correction on the local temperature rise value to obtain the operating condition corrected temperature rise value: The actual output power of the component is calculated using component voltage and component current, the irradiance value is calculated based on solar irradiance, and the air cooling heat dissipation value is calculated based on ambient wind speed. The solar irradiance under the rated power test conditions of photovoltaic modules is used as the reference solar irradiance, and the ratio of solar irradiance to the reference solar irradiance is used as the irradiance value. The operating condition correction temperature rise value is calculated using the actual output power of the components, the irradiation value, the air cooling heat dissipation value, the dust accumulation amount, and the local temperature rise value. The amount of dust accumulation is calculated by collecting the light transmittance of the clean reference sheet and the light transmittance of the dust sampling sheet. Based on the temperature rise value corrected under operating conditions, the temperature rise response difference, the unit irradiation temperature rise response, and the residual temperature rise are calculated. The comprehensive score of the thermal zone response and the output power deviation are also calculated. The comprehensive score of the thermal zone response and the output power deviation are used to screen for anomalies in the corresponding thermal zones, thus identifying thermoelectric correlation anomalies. The specific steps are as follows: Differential calculations are performed on the temperature rise values ​​corrected for adjacent operating conditions to obtain the temperature rise response difference component; The solar irradiance is differentially calculated to obtain the change in solar irradiance. The ratio of the temperature rise response difference to the change in solar irradiance is taken as the temperature rise response per unit irradiance. Calculate the average value of the operating condition corrected temperature rise for all the hot zones as the base temperature rise, and use the base temperature rise and the operating condition corrected temperature rise to calculate the residual temperature rise. The temperature rise response difference component, the temperature rise response amount per unit irradiation, and the temperature rise residual amount were normalized to obtain the normalized temperature rise response difference component, the normalized temperature rise response amount, and the normalized temperature rise residual amount. The sum of the normalized temperature rise response difference, the normalized temperature rise response quantity, and the normalized temperature rise residual quantity is used as the comprehensive score of the thermal zone response. The average value of the comprehensive score of the thermal response is calculated as the benchmark for the comprehensive score. Thermal areas whose comprehensive scores of thermal response are higher than the benchmark for the comprehensive score are identified as candidate abnormal thermal areas. The deviation of output power is calculated using the actual output power of the component, the amount of dust accumulation, and the irradiation effect. Candidate abnormal hot zones with output power deviations exceeding a preset deviation threshold are identified as thermoelectric-related abnormal hot zones. A base contribution ratio is set for the hot zone of each trusted fiber clip. The base contribution ratio is adjusted based on the abnormal hot zone caused by thermoelectric correlation to obtain the adjusted contribution ratio. The backplane representative temperature and thermal risk index are calculated based on the adjusted contribution ratio, and a closed-loop record of the component thermal state is established. The specific steps are as follows: The operating condition correction temperature rise value corresponding to the trusted fiber clip is taken as the trusted hot zone temperature rise value, and the backplane contact temperature corresponding to the trusted fiber clip is taken as the trusted backplane temperature. A basic contribution ratio is set for the thermal zone of each trusted fiber clip based on the thermal zone to which the trusted fiber clip belongs and the thermoelectric correlation abnormal thermal zone. The basic contribution ratio of each hot zone is evenly distributed to each trusted fiber clip to obtain the corrected contribution ratio of each trusted fiber clip. The correction contribution ratio corresponding to the thermoelectric associated abnormal hot zone is adjusted, while the correction contribution ratio corresponding to the non-thermoelectric associated abnormal hot zone remains unchanged, thus obtaining the adjusted contribution ratio. The sum of all adjustment contribution ratios is taken as the total contribution ratio, and the ratio of the adjustment contribution ratio of each trusted fiber clip to the total contribution ratio is taken as the thermal fidelity contribution ratio of each trusted fiber clip. The thermal fidelity contribution ratio of each trusted fiber clip is used as a weight to weight and sum the trusted backplane temperatures to obtain the representative backplane temperature. The highest value of the backplate contact temperature corresponding to the thermoelectric abnormal hot zone is taken as the highest abnormal backplate contact temperature. When the highest abnormal backplate contact temperature is higher than the representative temperature of the backplate, the highest abnormal backplate contact temperature is used as the thermal risk indicator. When there is no thermoelectric abnormal hot zone, the representative temperature of the backplate is used as the thermal risk indicator. The thermal status level of photovoltaic modules is classified according to the temperature represented by the backsheet, thermal risk indicators, and abnormal thermal zones associated with thermoelectricity. The fiber clip number, backplane coordinates, the corresponding hot zone and the corresponding substring number of the thermoelectric correlation abnormal hot zone are used as the hot zone positioning information. Pre-set operation and maintenance actions are assigned to photovoltaic modules based on hot zone location information and thermal status level; The preset maintenance actions, fiber optic hot zone address chain, local temperature rise value, operating condition correction temperature rise value, thermoelectric abnormal hot zone, backplane representative temperature and thermal risk indicators are merged into a closed-loop record of component thermal status.

2. A photovoltaic module backsheet temperature detection system, based on the photovoltaic module backsheet temperature detection method of claim 1, characterized in that, include: The association module deploys fiber clips on the backplane of the photovoltaic module and associates the sensing fiber segment, isolation fiber segment, backplane coordinates, hot zone and corresponding substring number of each fiber clip to form a fiber hot zone address chain. The marking module calculates the local temperature rise value based on the fiber optic hot zone address chain and marks the trusted fiber clips; The calibration module acquires solar irradiance, ambient wind speed, dust accumulation, component voltage, and component current, and performs operating condition correction on the local temperature rise value to obtain the operating condition corrected temperature rise value. The screening module calculates the temperature rise response difference, unit irradiation temperature rise response, and temperature rise residue based on the operating condition corrected temperature rise value, and calculates the comprehensive score of the hot zone response and the output power deviation. It uses the comprehensive score of the hot zone response and the output power deviation to screen the hot zones for anomalies and obtain the thermoelectric correlation abnormal hot zones. The recording module sets a basic contribution ratio for the hot zone of each trusted fiber clip, adjusts the basic contribution ratio based on the abnormal hot zone of thermoelectric correlation to obtain the adjusted contribution ratio, calculates the backplane representative temperature and thermal risk index based on the adjusted contribution ratio, and establishes a closed-loop record of the component thermal state.

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