Fireproof early warning system utilizing photovoltaic energy supply

Abstract

The invention relates to the field of early warning systems, and discloses a fireproof early warning system using photovoltaic energy supply, and the system comprises a data collection module which is used for obtaining the operation data of a photovoltaic device at a fixed position according to a fixed time interval, and the operation data comprises an illumination image of the photovoltaic device; the installation position data of the power cable of the photovoltaic device and the environmental parameter data of the installation environment of the photovoltaic device are acquired, and the environmental parameter data comprise wind speed, wind direction, temperature and illumination intensity; the first analysis module is used for processing the illumination image to identify a shadow area, an illumination area and an illumination angle in the illumination image, determining the illumination area of the photovoltaic device based on the illumination area, and calculating the input power of the photovoltaic device according to the illumination angle, the illumination area and the illumination intensity; and the second analysis module is used for dividing the power cable into a plurality of sub-segments based on the shadow area and the illumination area in the illumination image and the installation position data of the power cable.

Description

Technical Field

[0001] The present invention relates to the field of early warning systems, and more particularly to a fire prevention early warning system utilizing photovoltaic energy supply. Background Art

[0002] Existing photovoltaic devices are usually equipped with heat dissipation devices to cope with the heat generated during operation. However, due to the length limitation of power cables, the heat dissipation effect is poor. Especially under the scorching sun in summer, it is easy to overheat due to heat accumulation, and even cause fire. In order to monitor the temperature of power cables, the existing technology usually chooses to install temperature detection devices at multiple locations of the cable. However, due to the long length of power cables, this method requires the installation of a large number of temperature detection devices, which not only increases costs, but also brings great challenges in maintenance and management. Summary of the invention

[0003] The present invention provides a fire prevention early warning system using photovoltaic energy supply, which solves the technical problems raised in the background technology.

[0004] The present invention provides a fire prevention early warning system using photovoltaic power supply, comprising:

[0005] Data acquisition module, used to collect data at fixed locations and at fixed time intervals Acquire operation data of the photovoltaic device, the operation data including illumination images of the photovoltaic device, installation location data of power cables of the photovoltaic device and environmental parameter data of the installation environment of the photovoltaic device, the environmental parameter data including wind speed, wind direction, temperature and light intensity;

[0006] A first analysis module is used to process the illumination image to identify the shadow area, the illumination area and the illumination angle therein, determine the illumination area of ​​the photovoltaic device based on the illumination area, and calculate the input power of the photovoltaic device according to the illumination angle, the illumination area and the illumination intensity;

[0007] The second analysis module is used to divide the power cable into several sub-segments based on the shadow area and the light area in the illumination image and the installation position data of the power cable; calculate the transmission efficiency of each sub-segment respectively in combination with the wind speed, wind direction and temperature, and summarize the total transmission efficiency of the power cable;

[0008] A data checking module, used for predicting the output power of the photovoltaic device according to the input power of the photovoltaic device and the total transmission efficiency of the power cable, and comparing the predicted output power with the actual output power of the photovoltaic device to generate a prediction deviation;

[0009] The early warning module is used to evaluate the heat accumulation risk of power cables based on the prediction deviation; when the heat accumulation risk reaches the preset threshold, a fire warning signal is generated and an early warning is issued.

[0010] Further, the illumination image is processed to identify shadow areas and illumination areas therein, including:

[0011] Step 1, semantically segmenting the illumination image to obtain a number of photovoltaic panel segmentation maps in the illumination image, and graying the photovoltaic panel segmentation maps to obtain the gray value of each pixel in the photovoltaic panel segmentation maps;

[0012] Step 2, compare the gray values ​​of adjacent pixels, determine several edges of the photovoltaic panel segmentation map, and screen the edges of all photovoltaic panels to remove non-linear edges;

[0013] Step 3: Combine all the photovoltaic panel segmentation images and the edges of the straight lines in the corresponding photovoltaic panel segmentation images to identify the shadow area and the illuminated area, as follows:

[0014] Extend the two ends of the straight line edge in the photovoltaic panel segmentation diagram to a length equal to the photovoltaic panel installation spacing. ; If the edges of the extended straight lines intersect, the corresponding edges are connected and retained, otherwise the non-connected edges are removed to obtain a connected geometric graph; the connected geometric graph is mapped to the illumination image, and the grayscale values ​​of the pixels on both sides of the connected geometric graph in the illumination image are compared to obtain the shadow area and the illuminated area.

[0015] Further, identification of lighting angles includes:

[0016] Step 4, obtaining the longitude and latitude of the photovoltaic device installation location, and the date and time when the illumination image was taken;

[0017] Step 5: Calculate the angle of the sun relative to the Earth's equatorial plane , the formula is as follows: ;in, Indicates the date when the illumination image was taken, Indicates the number of days from the spring equinox. Indicates the maximum value of the Earth's obliquity;

[0018] Calculate the angle between the sun and the top of the photovoltaic installation , the formula is as follows: ;in, Indicates the latitude of the location where the photovoltaic device is installed, Indicates the time when the illumination image was taken, Indicates the angle of the sun's movement per hour;

[0019] Calculate the horizontal angle of the sun relative to north , the formula is as follows: ;in, Represents inverse trigonometric function calculation operations;

[0020] Calculate the angle between the sun's rays and the ground level based on the refraction of light by the atmosphere , the formula is as follows: ;in, express, Indicates the refraction correction value;

[0021] Step 6: Calculate the lighting angle , the calculation formula is as follows: ;in, Indicates the adjustment factor for increasing the solar declination.

[0022] Further, determining the illumination area of ​​the photovoltaic device based on the illumination area includes:

[0023] Step 7: Determine the total number of pixels of the photovoltaic panel in the illuminated area based on the shadow area and the illuminated area. , and the total number of pixels of the photovoltaic panel in the shadow area ;

[0024] Step 8: Get the total photovoltaic panel area ;

[0025] Step 9, according to The illumination area of ​​the photovoltaic device is .

[0026] Furthermore, the input power of the photovoltaic device is calculated according to the illumination angle, illumination area and illumination intensity, and the formula is as follows: ; ; ; ;

[0027] in, represents the input power of the photovoltaic device, is the unit vector representing the sun's position, The unit vector representing the direction of the photovoltaic panel, represents the correction matrix, Indicates the light intensity, represents the inclination angle of the photovoltaic panel, represents the orientation angle of the photovoltaic panel, Represents the photoelectric conversion efficiency of photovoltaic panels. represents the transpose operation, represents the calculation operation of the modulus length, Represents the weight coefficient.

[0028] Furthermore, based on the shadow area and the illuminated area in the illumination image and the installation position data of the power cable, the power cable is divided into several sub-segments, including:

[0029] Step 10, performing a first division on the power cable according to the illuminated area and the shadowed area to obtain illuminated sub-segments and shadowed sub-segments;

[0030] Step 11, obtaining installation position data of the power cable, the installation position data including thermal conductivity and heat absorption rate of the material to which the power cable is fixed, and performing a second division on the illuminated sub-segment and shadowed sub-segment of the power cable according to the installation position data to obtain a plurality of illuminated sub-segments and shadowed sub-segments.

[0031] Furthermore, the transmission efficiency of each sub-section is calculated separately by combining wind speed, wind direction and temperature, and the total transmission efficiency of the power cable is summarized, including:

[0032] Step 12, calculate the temperature rise of the i-th sub-segment, as follows:

[0033] If the i-th sub-segment is an illuminated sub-segment, the temperature rise of the i-th sub-segment is calculated as follows: ;

[0034] If the i-th sub-segment is a shaded sub-segment, the calculation formula for the temperature rise of the i-th sub-segment is as follows: ;

[0035] in, represents the temperature rise of the illuminated sub-segment, represents the temperature rise of the shaded sub-segment, represents the current in the cable, Indicates the resistance per unit length of power cable, Indicates the heat absorption rate of the material of the power cable, Indicates the light intensity, Represents the surface area of ​​the illuminated or shadowed sub-segment, Indicates wind speed, Indicates the angle between the wind direction and the illuminated sub-segment or the shadowed sub-segment. represents the reflectivity of the power cable, represents the Stefan-Boltzmann constant, Indicates the temperature of the environment in which the photovoltaic device is installed;

[0036] Among them, the surface area of ​​the illuminated sub-segment or the shadowed sub-segment The calculation process is as follows:

[0037] Get the total length of the power cable , the total number of pixels of the power cable outline , and the total number of pixels of the outline of the illuminated or shadowed sub-segment ;

[0038] Calculate the surface area of ​​a lit or shadowed subsegment , ;in, Indicates the cross-sectional radius of the power cable, Indicates the length of the illuminated sub-segment or the shadowed sub-segment;

[0039] Step 13, calculating the transmission efficiency of the i-th sub-segment, as follows; ; ;

[0040] in, represents the transmission efficiency of the i-th illumination sub-segment, represents the transmission efficiency of the i-th shaded subsegment, represents the coefficient of resistance variation with temperature, Indicates the input voltage of the power cable;

[0041] Step 14, summarizing the total transmission efficiency of the power cable, as follows: ;

[0042] in, represents the total transmission efficiency of the power cable, Indicates the number of illumination sub-segments, An index indicating the number of illuminated subsegments, represents the transmission efficiency of the g-th illumination sub-segment, represents the length of the g-th illumination sub-segment, represents the number of shaded sub-segments, An index indicating the number of shaded subsegments, Indicates The transmission efficiency of the shaded sub-segment is Indicates The length of the shaded subsegment.

[0043] Further, the output power of the photovoltaic device is predicted, and the predicted output power is compared with the actual output power of the photovoltaic device to generate a prediction deviation, including:

[0044] Predict the output power of the photovoltaic device, and compare the predicted output power with the actual output power of the photovoltaic device to generate a prediction deviation, including:

[0045] Step 15, predict the output power of the photovoltaic device, the calculation formula is as follows: ;in, represents the predicted output power;

[0046] Step 16: compare the predicted output power with the actual output power to obtain a difference between the predicted output power and the actual output power, and use the difference as a prediction deviation.

[0047] Furthermore, based on the prediction deviation, the thermal accumulation risk of power cables is evaluated, including:

[0048] Step 17: Forecast deviation and fixed time interval Weighted to get extra calories;

[0049] Step 18, based on all the sub-segments of the power cable, determining the sub-segment with the shortest length;

[0050] Step 19, according to the heat capacity formula, calculate the additional temperature rise of the shortest sub-segment where the additional heat is concentrated, and add the temperature of the photovoltaic device installation environment to the additional temperature rise to obtain the final temperature of the shortest sub-segment;

[0051] Step 20, defining the heat accumulation risk according to the final temperature and the warning temperature threshold, specifically including:

[0052] If the final temperature is greater than or equal to the warning temperature threshold, the heat accumulation risk is abnormal, otherwise it is normal.

[0053] Further, early warning is carried out, including:

[0054] Step 21, determining the deviation between the final temperature and the warning temperature threshold, where the deviation is the ratio of the final temperature to the warning temperature threshold;

[0055] Step 22, if , then start the first process, if , then start the second process.

[0056] The beneficial effects of the present invention are as follows: by combining illumination image processing with dynamic data analysis, the operating environment of the photovoltaic device (such as light intensity, wind speed, wind direction, etc.) and the physical properties of the power cable (such as thermal conductivity, heat absorption) are fully integrated, and real-time monitoring, refined modeling and dynamic risk assessment are achieved to accurately calculate the potential risk of local heat accumulation in the cable, thereby improving the system's safety, reliability and ability to adapt to complex environmental changes. BRIEF DESCRIPTION OF THE DRAWINGS

[0057] Figure 1 This is an architectural diagram of a fire warning system using photovoltaic power supply according to the present invention. DETAILED DESCRIPTION

[0058] The subject matter described herein will now be discussed with reference to example implementations. It should be understood that the discussion of these implementations is only to enable those skilled in the art to better understand and implement the subject matter described herein, and the functions and arrangements of the elements discussed may be changed without departing from the scope of protection of the contents of this specification. Various examples may omit, replace, or add various processes or components as needed. In addition, the features described in some examples may also be combined in other examples.

[0059] like Figure 1 As shown, a fire warning system using photovoltaic power supply includes:

[0060] Data acquisition module, used to collect data at fixed locations and at fixed time intervals Acquire operation data of the photovoltaic device, the operation data including illumination images of the photovoltaic device, installation location data of power cables of the photovoltaic device and environmental parameter data of the installation environment of the photovoltaic device, the environmental parameter data including wind speed, wind direction, temperature and light intensity;

[0061] A first analysis module is used to process the illumination image to identify the shadow area, the illumination area and the illumination angle therein, determine the illumination area of ​​the photovoltaic device based on the illumination area, and calculate the input power of the photovoltaic device according to the illumination angle, the illumination area and the illumination intensity;

[0062] The second analysis module is used to divide the power cable into several sub-segments based on the shadow area and the light area in the illumination image and the installation position data of the power cable; calculate the transmission efficiency of each sub-segment respectively in combination with the wind speed, wind direction and temperature, and summarize the total transmission efficiency of the power cable;

[0063] A data checking module, used for predicting the output power of the photovoltaic device according to the input power of the photovoltaic device and the total transmission efficiency of the power cable, and comparing the predicted output power with the actual output power of the photovoltaic device to generate a prediction deviation;

[0064] The early warning module is used to evaluate the heat accumulation risk of power cables based on the prediction deviation; when the heat accumulation risk reaches the preset threshold, a fire warning signal is generated and an early warning is issued.

[0065] In one embodiment of the present invention, processing an illumination image to identify shadow areas and illumination areas therein includes:

[0066] Step 1, semantically segmenting the illumination image to obtain a number of photovoltaic panel segmentation maps in the illumination image, and graying the photovoltaic panel segmentation maps to obtain the gray value of each pixel in the photovoltaic panel segmentation maps;

[0067] Step 2, compare the gray values ​​of adjacent pixels, determine several edges of the photovoltaic panel segmentation map, and screen the edges of all photovoltaic panels to remove non-linear edges;

[0068] Step 3: Combine all the photovoltaic panel segmentation images and the edges of the straight lines in the corresponding photovoltaic panel segmentation images to identify the shadow area and the illuminated area, as follows:

[0069] Extend the two ends of the straight line edge in the photovoltaic panel segmentation diagram to a length equal to the photovoltaic panel installation spacing. ; If the edges of the extended straight lines intersect, the corresponding edges are connected and retained, otherwise the non-connected edges are removed to obtain a connected geometric graph; the connected geometric graph is mapped to the illumination image, and the grayscale values ​​of the pixels on both sides of the connected geometric graph in the illumination image are compared to obtain the shadow area and the illuminated area.

[0070] Specifically, in step 1, semantic segmentation of the illumination image may include:

[0071] The illumination image is acquired at a fixed position, so the position of the entity in the illumination image does not change. By selecting any illumination image as the reference image, and then annotating the entities in the reference image, a reference image for artificial semantic segmentation is obtained; the reference image is overlapped with any illumination image, that is, the annotation result in the reference image is mapped to any illumination image, to achieve automatic semantic segmentation.

[0072] The photovoltaic panel segmentation map is obtained through step 1. For the photovoltaic panel segmentation map, when a shadow is projected on the top of the photovoltaic panel and when light is irradiated on the top of the photovoltaic panel, the grayscale value of the surface is different. Then, the photovoltaic panel segmentation map is grayscaled to obtain a grayscaled photovoltaic panel segmentation map. If there is a shadow in the photovoltaic panel segmentation map, there is a boundary of grayscale values ​​in the grayscaled map.

[0073] For shadows, if they significantly affect the power generation efficiency of photovoltaic panels, the shadows exist in patches. Therefore, the boundaries of the grayscale values ​​of each photovoltaic panel segmentation map are extended. If the connection is successful, it is considered that the shadows on the two photovoltaic panels are connected in patches, so this is regarded as a patch of shadows that affects the power generation efficiency. Through the joint judgment of the shadows of photovoltaic panels, the identified shadow areas and light areas are obtained.

[0074] In one embodiment of the present invention, identifying the illumination angle includes:

[0075] Step 4, obtaining the longitude and latitude of the photovoltaic device installation location, and the date and time when the illumination image was taken;

[0076] Step 5: Calculate the angle of the sun relative to the Earth's equatorial plane , the formula is as follows: ;in, Indicates the date when the illumination image was taken, Indicates the number of days from the spring equinox. Indicates the maximum value of the Earth's obliquity;

[0077] Calculate the angle between the sun and the top of the photovoltaic installation , the formula is as follows: ;in, Indicates the latitude of the location where the photovoltaic device is installed, Indicates the time when the illumination image was taken, Indicates the angle of the sun's movement per hour;

[0078] Calculate the horizontal angle of the sun relative to north , the formula is as follows: ;in, Represents inverse trigonometric function calculation operations;

[0079] Calculate the angle between the sun's rays and the ground level based on the refraction of light by the atmosphere , the formula is as follows: ;in, express, Indicates the refraction correction value;

[0080] Step 6: Calculate the lighting angle , the calculation formula is as follows: ;in, Indicates the adjustment factor for increasing the solar declination.

[0081] Specifically, by obtaining basic data (step 4): longitude and latitude: the geographical location of the photovoltaic device, used to locate the relative position of the sun. Shooting date and time: used to calculate the change in the position of the sun in the sky on that day. Sun angle calculation (step 5): The angle of the sun relative to the equatorial plane of the earth: calculated based on the date, using the formula of the sun's declination. This formula is related to the change in the position of the sun relative to the earth in a year. The angle between the sun and the top: combined with longitude and latitude and time, the altitude angle of the sun is calculated to reflect the angle between the sun's rays and the vertical direction of the ground. The horizontal angle of the sun relative to the north: This is the horizontal component of the sun's direction relative to the ground, usually used to calculate the direction of the shadow. Refraction correction: Due to the refraction of light by the atmosphere, the directly calculated angle needs to be corrected to improve the accuracy of the calculation. Through the refraction correction formula, the real sun angle is corrected to the ground observation angle. Illumination angle calculation (step 6): Based on the above data, by adjusting the correction coefficient of the sun's declination, the actual illumination angle of the photovoltaic device is finally obtained. The formula includes the angle adjustment of the sun's position to ensure that the angle calculation is consistent with the installation orientation of the photovoltaic device. The entire process utilizes the astronomical formula for calculating the sun's position, combined with specific geographical and time data, as well as atmospheric influences, to ultimately accurately calculate the angle of illumination.

[0082] In one embodiment of the present invention, determining the illumination area of ​​the photovoltaic device based on the illumination area includes:

[0083] Step 7: Determine the total number of pixels of the photovoltaic panel in the illuminated area based on the shadow area and the illuminated area. , and the total number of pixels of the photovoltaic panel in the shadow area ;

[0084] Step 8: Get the total photovoltaic panel area ;

[0085] Step 9, according to The illumination area of ​​the photovoltaic device is .

[0086] In one embodiment of the present invention, the input power of the photovoltaic device is calculated according to the illumination angle, illumination area and illumination intensity, and the formula is as follows: ; ; ; ;

[0087] in, represents the input power of the photovoltaic device, is the unit vector representing the sun's position, The unit vector representing the direction of the photovoltaic panel, represents the correction matrix, Indicates the light intensity, represents the inclination angle of the photovoltaic panel, represents the orientation angle of the photovoltaic panel, Represents the photoelectric conversion efficiency of photovoltaic panels. represents the transpose operation, represents the calculation operation of the modulus length, Represents the weight coefficient.

[0088] Specifically, the number of pixels in the illuminated area and the shadowed area is determined (step 7). The illuminated area and the shadowed area on the photovoltaic panel are identified by image processing technology. The total number of pixels in the illuminated area and the shadowed area in the photovoltaic panel is counted. This is to further determine the relative proportion of each area on the photovoltaic panel.

[0089] Total photovoltaic panel area acquisition (step 8). Using the physical properties of the photovoltaic device (such as the known area of ​​the photovoltaic panel), the pixel information in the image is mapped to the actual area. This requires establishing a proportional relationship between image pixels and actual area.

[0090] Calculate the illuminated area (step 9). Combine the pixel ratio of the illuminated area with the total photovoltaic panel area to calculate the actual illuminated area of ​​the photovoltaic device and calculate the input power.

[0091] The combination of image processing and photovoltaic panel characteristics combines image processing with physical modeling. Through image processing technology, the illuminated area and shadow area of ​​the photovoltaic panel can be obtained in real time. This method can dynamically reflect the environmental changes in the actual operation of the photovoltaic device, which is a more accurate method than traditional static parameter measurement.

[0092] The dynamic nature of the illuminated area calculation dynamically determines the actual illuminated area of ​​the photovoltaic panel through the pixel ratio in the image. This method significantly improves the flexibility and accuracy of the calculation, especially when the lighting conditions are complex and changing (such as cloudy, partial shadows, etc.).

[0093] The comprehensive modeling of the direction of the sun and the photovoltaic panel incorporates the geometric relationship between the direction of the sun's rays and the normal vector of the photovoltaic panel into the input power calculation, reflecting the actual angle of the photovoltaic panel receiving light. This method of combining vector geometry and physical parameters can more accurately reflect the actual input power.

[0094] Correction of environmental influences: A correction matrix is ​​introduced into the input power calculation to correct the influence of non-ideal environment (such as reflection and refraction) on the input power.

[0095] In one embodiment of the present invention, based on the shadow area and the illuminated area in the illumination image and the installation position data of the power cable, the power cable is divided into several sub-segments, including:

[0096] Step 10, performing a first division on the power cable according to the illuminated area and the shadowed area to obtain illuminated sub-segments and shadowed sub-segments;

[0097] Step 11, obtaining installation position data of the power cable, the installation position data including thermal conductivity and heat absorption rate of the material to which the power cable is fixed, and performing a second division on the illuminated sub-segment and shadowed sub-segment of the power cable according to the installation position data to obtain a plurality of illuminated sub-segments and shadowed sub-segments.

[0098] Specifically, conventional methods usually rely on fixed environmental assumptions to calculate cable temperature rise and transmission efficiency, while the present invention dynamically determines illuminated areas and shadow areas through real-time analysis of illumination images.

[0099] Taking into account material and environmental factors, the present invention introduces the installation location data of power cables (such as the thermal conductivity and heat absorption of materials) into the heat transfer analysis. This innovation makes the calculation of heat accumulation and temperature rise closer to reality, especially when the performance of cable bonding materials varies significantly.

[0100] Refined sub-segment division. The traditional method of calculating cable heat conduction and energy transmission is often based on the assumption of uniformity of the entire area. The present invention can more accurately evaluate the performance of each part by further dividing the cable into multiple small sub-segments.

[0101] For example, a power cable passes through an illuminated area and a shadowed area, and the illuminated area and the shadowed area are segmented separately. The illuminated sub-segment is installed and fixed on a cement surface and a black rubber surface. Since the materials of the cement surface and the black rubber surface have very different abilities to absorb and radiate heat energy, the cement surface and the black rubber surface are segmented again.

[0102] In one embodiment of the present invention, the transmission efficiency of each sub-segment is calculated in combination with wind speed, wind direction and temperature, and the total transmission efficiency of the power cable is obtained by summarizing, including:

[0103] Step 12, calculate the temperature rise of the i-th sub-segment, as follows:

[0104] If the i-th sub-segment is an illuminated sub-segment, the temperature rise of the i-th sub-segment is calculated as follows: ;

[0105] If the i-th sub-segment is a shaded sub-segment, the calculation formula for the temperature rise of the i-th sub-segment is as follows: ;

[0106] in, represents the temperature rise of the illuminated sub-segment, represents the temperature rise of the shaded sub-segment, represents the current in the cable, Indicates the resistance per unit length of power cable, Indicates the heat absorption rate of the material of the power cable, Indicates the light intensity, Represents the surface area of ​​the illuminated or shadowed sub-segment, Indicates wind speed, Indicates the angle between the wind direction and the illuminated sub-segment or the shadowed sub-segment. represents the reflectivity of the power cable, represents the Stefan-Boltzmann constant, Indicates the temperature of the environment in which the photovoltaic device is installed;

[0107] Among them, the surface area of ​​the illuminated sub-segment or the shadowed sub-segment The calculation process is as follows:

[0108] Get the total length of the power cable , the total number of pixels of the power cable outline , and the total number of pixels of the outline of the illuminated or shadowed sub-segment ;

[0109] Calculate the surface area of ​​a lit or shadowed subsegment , ;in, Indicates the cross-sectional radius of the power cable, Indicates the length of the illuminated sub-segment or the shadowed sub-segment;

[0110] Step 13, calculating the transmission efficiency of the i-th sub-segment, as follows; ; ;

[0111] in, represents the transmission efficiency of the i-th illumination sub-segment, represents the transmission efficiency of the i-th shaded subsegment, represents the coefficient of resistance variation with temperature, Indicates the input voltage of the power cable;

[0112] Step 14, summarizing the total transmission efficiency of the power cable, as follows: ;

[0113] in, represents the total transmission efficiency of the power cable, Indicates the number of illumination sub-segments, An index indicating the number of illuminated subsegments, represents the transmission efficiency of the g-th illumination sub-segment, represents the length of the g-th illumination sub-segment, represents the number of shaded sub-segments, An index indicating the number of shaded subsegments, Indicates The transmission efficiency of the shaded sub-segment is Indicates The length of the shaded subsegment.

[0114] Specifically, this step first considers the temperature rise of each power cable segment (sub-segment) due to the environment and its own operating conditions. The factors affecting the temperature rise include the cable's own heating and solar radiation heat. Heat dissipation factors include radiation heat dissipation, convection heat dissipation and ambient temperature. In the shaded sub-segment, since the solar radiation heat is extremely small, only the balance between self-heating and heat dissipation is considered.

[0115] Determination of surface area: The surface area of ​​a sub-segment is closely related to heat transfer. By using image processing technology and combining the geometric properties of the power cable (such as radius and length), the surface area of ​​the illuminated sub-segment or the shadowed sub-segment can be accurately calculated. The size of the surface area directly affects the efficiency of heat dissipation and heat absorption.

[0116] The calculation of sub-segment transmission efficiency is based on the results of temperature rise calculation. The power transmission efficiency of each sub-segment will be affected by temperature. Temperature rise will lead to increased resistance: the resistance of the material increases with temperature. Efficiency decreases: higher resistance leads to increased energy loss and reduces the transmission efficiency of the sub-segment. The specific efficiency of each sub-segment is calculated based on the relationship between temperature rise and resistance change.

[0117] The total transmission efficiency is summarized, and finally, the transmission efficiency of all sub-segments is weighted and summarized. The length and efficiency of the illuminated sub-segment and the shadowed sub-segment jointly determine the overall transmission efficiency of the power cable.

[0118] In one embodiment of the present invention, predicting the output power of a photovoltaic device, and comparing the predicted output power with the actual output power of the photovoltaic device to generate a prediction deviation includes:

[0119] Step 15, predict the output power of the photovoltaic device, the calculation formula is as follows: ;in, represents the predicted output power;

[0120] Step 16: compare the predicted output power with the actual output power to obtain a difference between the predicted output power and the actual output power, and use the difference as a prediction deviation.

[0121] Specifically, through modeling analysis, the theoretical output power of the photovoltaic system is calculated based on the operating conditions of the photovoltaic device (such as light intensity, illumination area, illumination angle, cable transmission efficiency, etc.). This predicted power reflects the output capacity of the photovoltaic device under the current environmental conditions under ideal conditions.

[0122] Use actual measuring devices to obtain the actual output power of the photovoltaic system. This is the power output result under the actual operating conditions of the system.

[0123] The predicted theoretical output power is compared with the actual measured output power to obtain the deviation between the two. This deviation reflects possible operational anomalies in the photovoltaic system (such as local heat accumulation).

[0124] Based on the size of the deviation, it is possible to assess whether the photovoltaic device has performance anomalies or hidden dangers. When the deviation is large, the system can issue an alarm, providing a basis for timely maintenance measures.

[0125] In one embodiment of the present invention, evaluating the heat accumulation risk of a power cable based on the prediction deviation includes:

[0126] Step 17: Forecast deviation and fixed time interval Weighted to get extra calories;

[0127] Step 18, based on all the sub-segments of the power cable, determining the sub-segment with the shortest length;

[0128] Step 19, according to the heat capacity formula, calculate the additional temperature rise of the shortest sub-segment where the additional heat is concentrated, and add the temperature of the photovoltaic device installation environment to the additional temperature rise to obtain the final temperature of the shortest sub-segment;

[0129] Step 20, defining the heat accumulation risk according to the final temperature and the warning temperature threshold, specifically including:

[0130] If the final temperature is greater than or equal to the warning temperature threshold, the heat accumulation risk is abnormal, otherwise it is normal.

[0131] Specifically, the prediction deviation reflects the difference between the actual operation of the photovoltaic system and the theoretical prediction, which comes from heat accumulation. The prediction deviation is weighted with the fixed time interval to obtain the accumulated heat caused by the prediction deviation. This weighting method takes into account the impact of time on heat accumulation. In all power cable sub-segments, the problem is judged to be maximized, that is, it is assumed that all the heat is accumulated in the shortest sub-segment. If the smallest sub-segment is normal, the entire system is judged to be normal. Based on the heat capacity formula, the temperature rise caused by the additional heat brought by the prediction deviation is calculated. The temperature rise caused by the additional heat concentrated in the shortest sub-segment is calculated. The initial temperature of the photovoltaic device installation environment is superimposed on the additional temperature rise to obtain the final temperature of the shortest sub-segment. This step reflects the comprehensive impact of the local environment and operating conditions of the cable on heat accumulation. By comparing the final temperature of the shortest sub-segment with the preset safety temperature threshold, the heat accumulation risk of the sub-segment is evaluated. If the final temperature is greater than or equal to the warning temperature threshold, the heat accumulation risk is judged to be abnormal and the warning signal is triggered. If the final temperature is lower than the threshold, the risk status is normal.

[0132] In one embodiment of the present invention, performing an early warning includes:

[0133] Step 21, determining the deviation between the final temperature and the warning temperature threshold, where the deviation is the ratio of the final temperature to the warning temperature threshold;

[0134] Step 22, if , then start the first process, if , then start the second process.

[0135] Specifically, the first treatment includes not reporting a fire alarm, and the person in charge of the photovoltaic device handles it by himself. The second treatment includes reporting a fire alarm, and the fire alarm handles it.

[0136] The above describes an embodiment of the present embodiment, but the present embodiment is not limited to the above-mentioned specific implementation methods. The above-mentioned specific implementation methods are merely illustrative and not restrictive. Under the guidance of the present embodiment, ordinary technicians in this field can also make many forms, all of which are protected by the present embodiment.

Claims

1. A fire warning system using photovoltaic power supply, characterized in that: include: Data acquisition module, used to collect data at fixed locations and at fixed time intervals Acquire operation data of the photovoltaic device, the operation data including illumination images of the photovoltaic device, installation location data of power cables of the photovoltaic device and environmental parameter data of the installation environment of the photovoltaic device, the environmental parameter data including wind speed, wind direction, temperature and light intensity; A first analysis module is used to process the illumination image to identify the shadow area, the illumination area and the illumination angle therein, determine the illumination area of ​​the photovoltaic device based on the illumination area, and calculate the input power of the photovoltaic device according to the illumination angle, the illumination area and the illumination intensity; A second analysis module is used to divide the power cable into a plurality of sub-segments based on the shadow area and the illuminated area in the illumination image and the installation position data of the power cable; Combined with wind speed, wind direction and temperature, the transmission efficiency of each sub-section is calculated separately, and the total transmission efficiency of the power cable is summarized; A data checking module, used for predicting the output power of the photovoltaic device according to the input power of the photovoltaic device and the total transmission efficiency of the power cable, and comparing the predicted output power with the actual output power of the photovoltaic device to generate a prediction deviation; An early warning module is used to assess the thermal accumulation risk of power cables based on prediction deviations; When the heat accumulation risk reaches the preset threshold, a fire warning signal is generated and an early warning is issued.

2. A fire warning system using photovoltaic power supply according to claim 1, characterized in that: Processing of illuminated images to identify shadowed and illuminated areas, including: Step 1, semantically segmenting the illumination image to obtain a number of photovoltaic panel segmentation maps in the illumination image, and graying the photovoltaic panel segmentation maps to obtain the gray value of each pixel in the photovoltaic panel segmentation maps; Step 2, compare the gray values ​​of adjacent pixels, determine several edges of the photovoltaic panel segmentation map, and screen the edges of all photovoltaic panels to remove non-linear edges; Step 3: Combine all the photovoltaic panel segmentation images and the edges of the straight lines in the corresponding photovoltaic panel segmentation images to identify the shadow area and the illuminated area, as follows: Extend the two ends of the straight line edge in the photovoltaic panel segmentation diagram to a length equal to the photovoltaic panel installation spacing. ; If the edges of the extended straight lines intersect, the corresponding edges are connected and retained, otherwise the non-connected edges are removed to obtain a connected geometric graph; the connected geometric graph is mapped to the illumination image, and the grayscale values ​​of the pixels on both sides of the connected geometric graph in the illumination image are compared to obtain the shadow area and the illuminated area.

3. A fire warning system using photovoltaic power supply according to claim 2, characterized in that: Identify lighting angles, including: Step 4, obtaining the longitude and latitude of the photovoltaic device installation location, and the date and time when the illumination image was taken; Step 5: Calculate the angle of the sun relative to the Earth's equatorial plane , the formula is as follows: ;in, Indicates the date when the illumination image was taken, Indicates the number of days from the spring equinox. Indicates the maximum value of the Earth's obliquity; Calculate the angle between the sun and the top of the photovoltaic installation , the formula is as follows: ;in, Indicates the latitude of the location where the photovoltaic device is installed, Indicates the time when the illumination image was taken, Indicates the angle of the sun's movement per hour; Calculate the horizontal angle of the sun relative to north , the formula is as follows: ;in, Represents inverse trigonometric function calculation operations; Calculate the angle between the sun's rays and the ground level based on the refraction of light by the atmosphere , the formula is as follows: ;in, express, Indicates the refraction correction value; Step 6: Calculate the lighting angle , the calculation formula is as follows: ;in, Indicates the adjustment factor for increasing the solar declination.

4. A fire warning system using photovoltaic power supply according to claim 3, characterized in that: Determine the illuminated area of ​​the photovoltaic device based on the illuminated area, including: Step 7: Determine the total number of pixels of the photovoltaic panel in the illuminated area based on the shadow area and the illuminated area. , and the total number of pixels of the photovoltaic panel in the shadow area ; Step 8: Get the total photovoltaic panel area ; Step 9, according to The illumination area of ​​the photovoltaic device is .

5. A fire warning system using photovoltaic power supply according to claim 4, characterized in that: According to the illumination angle, illumination area and illumination intensity, the input power of the photovoltaic device is calculated as follows: ； ； ； ； in, represents the input power of the photovoltaic device, is the unit vector representing the sun's position, The unit vector representing the direction of the photovoltaic panel, represents the correction matrix, Indicates the light intensity, represents the inclination angle of the photovoltaic panel, represents the orientation angle of the photovoltaic panel, Represents the photoelectric conversion efficiency of photovoltaic panels. represents the transpose operation, represents the calculation operation of the modulus length, Represents the weight coefficient.

6. A fire warning system using photovoltaic power supply according to claim 5, characterized in that: Based on the shadow area and the illuminated area in the illumination image and the installation location data of the power cables, the power cables are divided into several sub-segments, including: Step 10, performing a first division on the power cable according to the illuminated area and the shadowed area to obtain illuminated sub-segments and shadowed sub-segments; Step 11, obtaining installation position data of the power cable, the installation position data including thermal conductivity and heat absorption rate of the material to which the power cable is fixed, and performing a second division on the illuminated sub-segment and shadowed sub-segment of the power cable according to the installation position data to obtain a plurality of illuminated sub-segments and shadowed sub-segments.

7. A fire warning system using photovoltaic power supply according to claim 6, characterized in that: Combined with wind speed, wind direction and temperature, the transmission efficiency of each sub-section is calculated separately, and the total transmission efficiency of the power cable is summarized, including: Step 12, calculate the temperature rise of the i-th sub-segment, as follows: If the i-th sub-segment is an illuminated sub-segment, the temperature rise of the i-th sub-segment is calculated as follows: ； If the i-th sub-segment is a shaded sub-segment, the calculation formula for the temperature rise of the i-th sub-segment is as follows: ； in, represents the temperature rise of the illuminated sub-segment, represents the temperature rise of the shaded sub-segment, represents the current in the cable, Indicates the resistance per unit length of power cable, Indicates the heat absorption rate of the material of the power cable, Indicates the light intensity, Represents the surface area of ​​the illuminated or shadowed sub-segment, Indicates wind speed, Indicates the angle between the wind direction and the illuminated sub-segment or the shadowed sub-segment. represents the reflectivity of the power cable, represents the Stefan-Boltzmann constant, Indicates the temperature of the environment in which the photovoltaic device is installed; Among them, the surface area of ​​the illuminated sub-segment or the shadowed sub-segment The calculation process is as follows: Get the total length of the power cable , the total number of pixels of the power cable outline , and the total number of pixels of the outline of the illuminated or shadowed sub-segment ; Calculate the surface area of ​​a lit or shadowed subsegment , ;in, Indicates the cross-sectional radius of the power cable, Indicates the length of the illuminated sub-segment or the shadowed sub-segment; Step 13, calculating the transmission efficiency of the i-th sub-segment, as follows; ； ； in, represents the transmission efficiency of the i-th illumination sub-segment, represents the transmission efficiency of the i-th shaded subsegment, represents the coefficient of resistance variation with temperature, Indicates the input voltage of the power cable; Step 14, summarizing the total transmission efficiency of the power cable, as follows: ； in, represents the total transmission efficiency of the power cable, Indicates the number of illumination sub-segments, An index indicating the number of illuminated subsegments, represents the transmission efficiency of the g-th illumination sub-segment, represents the length of the g-th illumination sub-segment, represents the number of shaded sub-segments, An index indicating the number of shaded subsegments, Indicates The transmission efficiency of the shaded sub-segment is Indicates The length of the shaded subsegment.

8. A fire warning system using photovoltaic power supply according to claim 7, characterized in that: Predict the output power of the photovoltaic device, and compare the predicted output power with the actual output power of the photovoltaic device to generate a prediction deviation, including: Step 15, predict the output power of the photovoltaic device, the calculation formula is as follows: ;in, represents the predicted output power; Step 16: compare the predicted output power with the actual output power to obtain a difference between the predicted output power and the actual output power, and use the difference as a prediction deviation.

9. A fire warning system using photovoltaic power supply according to claim 8, characterized in that: Evaluate the thermal accumulation risk of power cables based on prediction deviation, including: Step 17: Forecast deviation and fixed time interval Weighted to get extra calories; Step 18, based on all the sub-segments of the power cable, determining the sub-segment with the shortest length; Step 19, according to the heat capacity formula, calculate the additional temperature rise of the shortest sub-segment where the additional heat is concentrated, and add the temperature of the photovoltaic device installation environment to the additional temperature rise to obtain the final temperature of the shortest sub-segment; Step 20, defining the heat accumulation risk according to the final temperature and the warning temperature threshold, specifically including: If the final temperature is greater than or equal to the warning temperature threshold, the heat accumulation risk is abnormal, otherwise it is normal.

10. A fire warning system using photovoltaic power supply according to claim 9, characterized in that: Provide early warning, including: Step 21, determining the deviation between the final temperature and the warning temperature threshold, where the deviation is the ratio of the final temperature to the warning temperature threshold; Step 22, if , then start the first process, if , then start the second process.

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