Photovoltaic power generation safety monitoring system based on Brillouin distributed optical fiber sensing

Abstract

The invention provides a photovoltaic power generation safety monitoring system based on Brillouin distributed optical fiber sensing, and belongs to the technical field of photovoltaic power generation safety monitoring. In order to solve the snow accumulation problem of a photovoltaic panel in ice and snow weather and the short-circuit protection problem when a hot spot effect occurs, the technical scheme adopted by the invention is as follows: a BOTDR temperature detection sub-module detects temperature data in a to-be-detected optical fiber through Brillouin scattering, demodulates the temperature data and sends the temperature data to a data acquisition sub-module; the output end of the data acquisition sub-module is connected with the central control module; the central control module is connected with the user control module through the communication module, and the control end of the user control module is connected with the heating and short-circuit protection module; a partition heating switch and a junction box are arranged in the heating and short-circuit protection module; an intelligent photovoltaic panel, a photovoltaic power generation array and a storage battery are arranged in the photovoltaic power generation module; the method is applied to photovoltaic power generation safety monitoring.

Description

Technical Field

[0001] This invention provides a photovoltaic power generation safety monitoring system based on Brillouin distributed optical fiber sensing, belonging to the field of photovoltaic power generation safety monitoring technology. Background Technology

[0002] With the global energy structure transformation, photovoltaic power generation, as an important component of clean energy, has seen its installed capacity grow rapidly. However, most photovoltaic power plants currently in use are built in remote areas with harsh environments, facing challenges such as low temperatures and freezing, and grid fluctuations, which seriously affect power generation efficiency and system stability. Specifically: Traditional photovoltaic (PV) panels rely primarily on external mechanical devices for snow removal, which suffers from high energy consumption, low efficiency, and easy damage to components. Monitoring the condition of PV panels often uses traditional point sensors, which cannot achieve full-coverage sensing of the panel surface and make it difficult to accurately identify hot spot effects. Furthermore, they cannot withstand extreme working environments for extended periods; exposed sensor circuits are susceptible to icing, rain, and other weather conditions in extreme outdoor environments, resulting in low equipment survival rates. In addition, there is a lack of intelligent decision-making and timely intervention mechanisms; when risks are detected, manual troubleshooting is often required, and faulty equipment cannot automatically disconnect from the grid, impacting system power generation efficiency. Summary of the Invention

[0003] To address the technical problems existing in the background art, the present invention adopts the following technical solution: A photovoltaic power generation safety monitoring system based on Brillouin distributed optical fiber sensing is provided, comprising a central control module, an optical fiber temperature sensing and detection module, a communication module, a user control module, a heating and short-circuit protection module, and a photovoltaic power generation module, wherein: The fiber optic temperature sensing module includes a BOTDR temperature detection submodule and a data acquisition submodule. The BOTDR temperature detection submodule detects the temperature data in the fiber under test by Brillouin scattering and demodulates the temperature data before sending it to the data acquisition submodule. The output of the data acquisition submodule is connected to the central control module. The central control module is connected to the user control module via a communication module, and the control terminal of the user control module is connected to the heating and short-circuit protection module. The heating and short-circuit protection module is equipped with a zone heating switch and a junction box, while the photovoltaic power generation module is equipped with an intelligent photovoltaic panel, a photovoltaic power generation array, and a storage battery. The partition heating switch is used to control the alloy heating wires in different partitions of the smart photovoltaic panel; The junction box is used to control the circuit connection between the smart photovoltaic panel and the photovoltaic power generation array. The battery is used to power the photovoltaic power generation module.

[0004] The BOTDR temperature detection submodule internally includes: a narrow linewidth laser, a first coupler, a pulsed light modulator, a pulse amplifier, a circulator, an optical switch, an optical fiber under test, a random signal generator, an analog-to-digital converter, a continuous optical amplifier, an optical filter, a polarization controller, an IQ modulator, a microwave source, a bias control board, a second coupler, a polarization scrambler, a third coupler, a photodetector, a bandpass filter, and a low-noise amplifier, wherein: The output of the narrow linewidth laser is connected to the input of the pulsed light modulator and the input of the polarization controller via a first coupler. The output of the pulsed light modulator is connected to the input of the pulse amplifier, the output of the pulse amplifier is connected to the first input of the circulator, and the second input of the circulator is connected to the optical fiber under test through an optical switch. The first output terminal of the random signal generator is connected to the pulse light modulator, and the second output terminal of the random signal generator is connected to the trigger terminal of the data acquisition submodule through an analog-to-digital converter. The output of the circulator is connected to the input of the optical filter via a continuous optical amplifier; The output terminal of the polarization controller is connected to the first input terminal of the IQ modulator; The output terminal of the microwave source is connected to the second input terminal of the IQ modulator, and the output terminal of the bias control board is connected to the third input terminal of the IQ modulator. The output of the IQ modulator is connected to the input of the second coupler; The output of the second coupler is connected to the input of the polarization scrambler and the input of the bias control board, respectively. The output of the polarization scrambler is connected to the first input of the third coupler, and the second input of the third coupler is connected to the output of the optical filter. The output of the third coupler is connected to the input of the data acquisition submodule in sequence through a photodetector, a bandpass filter, and a low-noise amplifier.

[0005] The output light of the narrow linewidth laser is split into two parts with intensities of 10% and 90% by the first coupler; 90% of the continuous light passes through a pulse light modulator connected to a random signal generator and is modulated into a pulse signal encoded with a true random number sequence. The code length of the pulse signal is 640 bits.

[0006] The polarization controller is used to adjust the polarization state of the reference light; The microwave source is used to generate a frequency shift signal, so that the frequency of continuous light varies in the range of 10-11 GHz; The bias control board stabilizes the output of the IQ modulator based on the intensity of the input light.

[0007] The optical switch controls channel parameters to switch between measuring the temperature information of multiple optical fibers under test.

[0008] The intelligent photovoltaic panel includes tempered glass, a flame-retardant EVA composite layer, an optical fiber interface, a photovoltaic cell layer, an EVA backsheet, an alloy backsheet, flame-retardant EVA filler adhesive, an alloy heating wire, and loose-tube optical fibers, wherein: The alloy heating wire and loose-tube optical fiber are laid in the flame-retardant EVA composite layer for distributed sensing of the working temperature of the photovoltaic power generation array. The mounting end of the loose-tube optical fiber is connected to the optical fiber interface for connection with other photovoltaic panels; The mounting end of the alloy heating wire is connected to the zone heating switch to realize heating control of photovoltaic panels in different zones; The output terminal of the photovoltaic cell layer is connected to the junction box to achieve short-circuit protection for the photovoltaic panel.

[0009] The advantages of this invention compared to existing technologies are as follows: Addressing the issues of snow accumulation on photovoltaic panels in extreme weather and the protection of the entire power generation matrix when hot spot effects occur, this invention proposes a distributed optical fiber sensing monitoring system based on Brillouin distributed optical fiber sensing and relying on optical switches. The system uses Brillouin scattering and anti-Stokes light to demodulate temperature information along the optical fiber. Compared to traditional safety monitoring methods, this system uses optical fiber as the medium and signal light as the carrier, enabling it to not only sense external signals but also transmit sensor signals. By judging the temperature changes on the photovoltaic panel surface, the location of snow accumulation or hot spot effects can be quickly pinpointed. Based on the obtained temperature information, the monitoring system can also utilize the heating wires integrated in the smart photovoltaic panel to implement targeted zoned heating measures for photovoltaic panels with snow accumulation and to proactively disconnect circuits for photovoltaic panels exhibiting hot spot effects to protect the entire photovoltaic power generation matrix. The entire system has advantages such as high sensitivity, good insulation, large bandwidth, distributed operation, and long-distance operation, exhibiting good reliability in application scenarios involving multi-object detection, wide coverage, and difficult manual maintenance. Attached Figure Description

[0010] The present invention will be further described below with reference to the accompanying drawings: Figure 1 This is a schematic diagram of the photoelectric composite monitoring system of the present invention; Figure 1 The meanings of each number are as follows: 1-Central control module; 2-Fiber optic temperature sensing module; 3-Communication module; 4-User control module; 5-Heating and short-circuit protection module; 51-Zone heating switch; 52-Junction box; 6-Photovoltaic power generation module; 61-Intelligent photovoltaic panel; 62-Photovoltaic power generation array; 63-Battery.

[0011] Figure 2This is a schematic diagram of the internal structure of the fiber optic temperature sensing and detection module of the present invention; Figure 2 The meanings of the serial numbers are as follows: 21-Narrow linewidth laser; 22-First coupler; 23-Pulse light modulator; 24-Pulse amplifier; 25-Circulator; 26-Optical switch; 27-Fiber under test; 28-Random signal generator; 29-Analog-to-digital converter; 210-Data acquisition submodule; 211-Continuous optical amplifier; 212-Optical filter; 213-Polarization controller; 214-IQ modulator; 215-Microwave source; 216-Bias control board; 217-Second coupler; 218-Polarization scrambler; 219-Third coupler; 220-Photodetector; 221-Bandpass filter; 222-Low noise amplifier.

[0012] Figure 3 This is a schematic diagram of the structure of the smart photovoltaic panel of the present invention; Figure 3 The meanings of the serial numbers are as follows: 7-tempered glass; 8-flame-retardant EVA composite layer; 9-fiber optic connector; 10-photovoltaic cell layer; 11-EVA backsheet; 12-alloy backsheet; 13-flame-retardant EVA filler adhesive; 14-alloy heating wire; 15-loose-tube optical fiber. Detailed Implementation

[0013] This invention addresses the issues of snow accumulation on photovoltaic (PV) panels during icy and snowy weather and short-circuit protection during hot spot effects. It provides a PV power generation safety monitoring system based on Brillouin distributed optical fiber sensing, primarily comprising a smart PV panel structural design and a distributed temperature sensing monitoring and control system based on Brillouin scattering. The flame-retardant EVA composite layer of the smart PV panel collects temperature information, and the demodulated temperature information determines whether to heat or disconnect the PV panel. The distributed temperature sensing monitoring and control system transmits temperature information through the sensing optical fiber of the smart PV panel. This temperature information is demodulated by a Brillouin temperature demodulation module and then transmitted to a central control module. The central control module generates temperature distribution signals and alarm signals, which are then transmitted to the mobile control device via the communication module. The mobile control device controls the zone heating switches to protect the photovoltaic panels from snow accumulation and provides short-circuit protection for the entire photovoltaic array in case of hot spot effects through the photovoltaic panel junction box. This invention utilizes Brillouin dispersion radio frequency shift for temperature measurement, integrating distributed sensing optical fibers and heating wires onto the photovoltaic panel. The photovoltaic panel temperature is sensed in real time through the optical fiber, allowing users to take timely heating and short-circuit protection measures. The entire monitoring system has advantages such as accurate positioning, zoned control, high measurement accuracy, and good real-time performance, which can save on the maintenance costs of the photovoltaic array.

[0014] The structures, proportions, sizes, etc., shown in the accompanying drawings of this invention are only for the purpose of assisting those skilled in the art in understanding and reading the content disclosed in the specification, and are not intended to limit the conditions under which the invention can be implemented. Therefore, they have no substantial technical significance. Any modifications to the structure, changes in the proportional relationships, or adjustments to the size, without affecting the effects and objectives that the invention can produce, should fall within the scope of the technical content disclosed in this invention. It should be noted that in this specification, relational terms such as "first" and "second" are only used to distinguish one entity from several other entities, and do not necessarily require or imply any actual relationship or order between these entities.

[0015] like Figure 1 , Figure 2 , Figure 3 As shown, the photovoltaic power generation safety monitoring system based on Brillouin distributed optical fiber sensing provided by the present invention mainly includes: a central control module 1, an optical fiber temperature sensing module 2, a communication module 3, a user control module 4, a heating and short circuit protection module 5, and a photovoltaic power generation module 6. The fiber optic temperature sensing module 2 includes a BOTDR temperature detection submodule and a data acquisition submodule. It determines the temperature information in the fiber under test through Brillouin scattering. After data demodulation, it is transmitted to the data acquisition submodule, which mainly includes a high-speed acquisition card and its corresponding supporting circuits, used to acquire the signal output by the BOTDR temperature detection submodule. The acquired signal will be sent to the central control module for further processing.

[0016] The central control module receives signals collected by the fiber optic temperature sensing module, demodulates the response generated by the random pulse-coded light pulse through cross-correlation calculation, compares the acquired temperature information with a preset threshold, and sends the alarm signal and temperature information to the user control module via the communication module. The user can then control the heating and short-circuit protection modules. Zone heating switches control the alloy heating wires in different zones of the intelligent photovoltaic panels within the photovoltaic power generation module. The junction box controls the circuit connection between the intelligent photovoltaic panels and the photovoltaic array within the photovoltaic power generation module. A storage battery powers the modules within the system. The communication module enables data exchange between the various modules of the system; while the photovoltaic power generation module generates electricity, it also provides energy to the other modules within the system.

[0017] Loose-tube optical fibers and alloy heating wires are integrated into the flame-retardant EVA composite layer of the smart photovoltaic panel in a serpentine layout. This is used for distributed sensing of the working area temperature of a large-area photovoltaic power generation array. It can detect snow accumulation and hot spot effects on the photovoltaic panel in a timely manner, and snow melting can be achieved through remote control of the alloy heating wires.

[0018] The components of the BOTDR temperature detection submodule include a narrow-linewidth laser 21, a first coupler 22, a pulsed light modulator 23, a pulse amplifier 24, a circulator 25, an optical switch 26, an optical fiber under test 27, a random signal generator 28, an analog-to-digital converter 29, a continuous optical amplifier 211, an optical filter 212, a polarization controller 213, an IQ modulator 214, a microwave source 215, a bias control board 216, a second coupler 217, a polarization scrambler 218, a third coupler 219, a photodetector 220, a bandpass filter 221, and a low-noise amplifier 222, wherein: The output of the narrow linewidth laser 21 is connected to the input of the pulsed light modulator 23 and the polarization controller 213 via the first coupler 22. The output of the pulsed light modulator 23 is connected to the input of the pulse amplifier 24, the output of the pulse amplifier 24 is connected to the first input of the circulator 25, and the second input of the circulator 25 is connected to the optical fiber 27 under test through the optical switch 26. The first output terminal of the random signal generator 28 is connected to the pulse light modulator 23, and the second output terminal is connected to the trigger terminal of the data acquisition submodule 210 through the analog-to-digital converter 29. The output of the circulator 25 is connected to the input of the optical filter 212 via the continuous optical amplifier 211; The output of the polarization controller 213 is connected to the first input of the IQ modulator 214; The output terminal of the microwave source 215 is connected to the second input terminal of the IQ modulator 214, and the output terminal of the bias control board 216 is connected to the third input terminal of the IQ modulator 214. The output of the IQ modulator 214 is connected to the input of the second coupler 217; The output of the second coupler 217 is connected to the input of the polarizer 218 and the input of the bias control board 216, respectively. The output of the polarizer 218 is connected to the first input of the third coupler 219, and the second input of the third coupler 219 is connected to the output of the optical filter 212. The output of the third coupler 219 is connected to the input of the data acquisition submodule 210 after passing through the photodetector 220, the bandpass filter 221, and the low-noise amplifier 222 in sequence.

[0019] In the BOTDR temperature monitoring submodule, the output light of the narrow linewidth laser 21 is split into two parts by the first coupler 22: a reference light with an intensity of 10% and a probe light with an intensity of 90%. The 90% continuous light is modulated into a true random number sequence encoded pulse by a pulse light modulator 23 connected to a random signal generator 28. The pulse code length is 640 bits. The other output of the random signal generator 28 is converted into a digital signal by an analog-to-digital converter 29 and then used as a trigger signal to be transmitted to the trigger terminal of the data acquisition submodule 210.

[0020] The polarization controller 213 adjusts the polarization state of the reference light to meet the polarization state requirements of the IQ modulator 214. The microwave source 215 generates a frequency shift signal, shifting the frequency of the continuous light within the 10-11 GHz range. The output light of the IQ modulator 214 is split into 10% and 90% portions by the second coupler 217. The 10% portion is used as an intensity reference input to the bias control board 216, which stabilizes the output of the IQ modulator 214 according to the intensity of the input light. The 90% output portion passes through the polarization scrambler 218, increasing the randomness of the light's polarization state and effectively improving the beat frequency effect. After the probe light and reference light are coupled at the third coupler 219 at a 50% ratio, the output light is converted into a same-frequency electrical signal by the photodetector 220. Subsequently, it undergoes frequency component separation processing by the bandpass filter 221 and low-intensity signal amplification processing by the low-noise amplifier 222 before being transmitted to the data acquisition submodule 210 for digital signal extraction.

[0021] The present invention also provides a structural design for an intelligent photovoltaic panel, the structure including tempered glass 7, flame-retardant EVA composite layer 8, optical fiber interface 9, photovoltaic cell layer 10, EVA back sheet 11, alloy back sheet 12, flame-retardant EVA filler 13, alloy heating wire 14, loose-tube optical fiber 15, zone heating switch 51 and junction box 52; the alloy heating wire 14 and loose-tube optical fiber 15 are laid in a serpentine pattern in the flame-retardant EVA composite layer 8.

[0022] The end of the loose-tube optical fiber 15 is connected to the optical fiber interface 9 for connection with other photovoltaic panels; the zone heating switch 51 is connected to the alloy heating wire 14 to realize heating control of photovoltaic panels in different zones; the junction box 52 is connected to the photovoltaic cell layer 10 to realize short-circuit protection of the photovoltaic panel.

[0023] This invention proposes a photoelectric composite monitoring system that integrates multi-dimensional environmental data such as illumination, temperature, and voltage to construct a predictive model for icing on photovoltaic panel surfaces, enabling accurate prediction and proactive early warning of freezing risks. Combined with heating technology, it achieves efficient and energy-saving snow protection. Simultaneously, the system employs a serpentine arrangement of sensing fibers to simultaneously sample multiple locations, effectively monitoring hot spot effects that are difficult to detect with traditional point sensors, achieving distributed temperature monitoring of photovoltaic panel surfaces. The sensing fibers are connected to the system via a serial fiber optic interface, simplifying the sensor system access method and constructing a stable and flexible modular sensing system. This invention integrates sensors and communication modules, enabling comprehensive perception and real-time transmission of data such as environmental parameters, system operating status, and fault information. This provides data support for intelligent decision-making, improves system operating efficiency and reliability, effectively solves the challenges of snow protection and power outage protection faced by photovoltaic power plants, improves power generation efficiency, reduces operation and maintenance costs, and ensures the safe and stable operation of the power grid, which is of great significance for promoting the high-quality development of the photovoltaic industry.

[0024] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, and not to limit them; although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some or all of the technical features; and these modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of the present invention.

Claims

1. A photovoltaic power generation safety monitoring system based on Brillouin distributed optical fiber sensing, characterized in that: It comprises a central control module (1), a fiber temperature sensing detection module (2), a communication module (3), a user control module (4), a heating and short circuit protection module (5) and a photovoltaic power generation module (6), wherein: The fiber temperature sensing detection module (2) comprises a BOTDR temperature detection submodule and a data acquisition submodule (210), the BOTDR temperature detection submodule detects temperature data in the measured fiber (27) through Brillouin scattering, and sends the demodulated temperature data to the data acquisition submodule (210), and the output end of the data acquisition submodule (210) is connected with the central control module (1); The central control module (1) is connected with the user control module (4) through the communication module (3), and the control end of the user control module (4) is connected with the heating and short circuit protection module (5); The heating and short circuit protection module (5) is internally provided with a partition heating switch (51) and a junction box (52), and the photovoltaic power generation module (6) is internally provided with an intelligent photovoltaic panel (61), a photovoltaic power generation array (62) and a storage battery (63); The partition heating switch (51) is used for controlling the alloy heating wire of different partitions of the intelligent photovoltaic panel (61); The junction box (52) is used for controlling the circuit connection between the intelligent photovoltaic panel (61) and the photovoltaic power generation array (62); The storage battery (63) is used for power supply for the photovoltaic power generation module (6). 2.The photovoltaic power generation safety monitoring system based on Brillouin distributed optical fiber sensing according to claim 1, characterized in that: The BOTDR temperature detection submodule internally comprises a narrow linewidth laser (21), a first coupler (22), a pulse light modulator (23), a pulse amplifier (24), a circulator (25), an optical switch (26), a measured fiber (27), a random signal generator (28), an analog-to-digital converter (29), a continuous light amplifier (211), an optical filter (212), a polarization controller (213), an IQ modulator (214), a microwave source (215), a bias control board (216), a second coupler (217), a depolarizer (218), a third coupler (219), a photodetector (220), a band-pass filter (221) and a low-noise amplifier (222), wherein: The output end of the narrow linewidth laser (21) is connected with the input end of the pulse light modulator (23) and the input end of the polarization controller (213) through the first coupler (22); The output end of the pulse light modulator (23) is connected with the input end of the pulse amplifier (24), the output end of the pulse amplifier (24) is connected with the first input end of the circulator (25), and the second input end of the circulator (25) is connected with the measured fiber (27) through the optical switch (26); The first output end of the random signal generator (28) is connected with the pulse light modulator (23), and the second output end of the random signal generator (28) is connected with the trigger end of the data acquisition submodule (210) through the analog-to-digital converter (29); The output end of the circulator (25) is connected with the input end of the optical filter (212) through the continuous light amplifier (211). The output end of the polarization controller (213) is connected with the first input end of the IQ modulator (214); The output end of the microwave source (215) is connected with the second input end of the IQ modulator (214), and the output end of the bias control board (216) is connected with the third input end of the IQ modulator (214); The output end of the IQ modulator (214) is connected with the input end of the second coupler (217); The output end of the second coupler (217) is connected with the input end of the depolarizer (218) and the input end of the bias control board (216) respectively, the output end of the depolarizer (218) is connected with the first input end of the third coupler (219), and the second input end of the third coupler (219) is connected with the output end of the optical filter (212); The output end of the third coupler (219) is connected with the input end of the data acquisition submodule (210) through the photoelectric detector (220), the band-pass filter (221) and the low-noise amplifier (222) in sequence. 3.The photovoltaic power generation safety monitoring system based on Brillouin distributed optical fiber sensing according to claim 2, characterized in that: The output light of the narrow linewidth laser (21) is divided into two parts with intensity of 10% and 90% through the first coupler (22); The 90% continuous light is modulated into a pulse signal with a code length of 640 bits by a pulse light modulator (23) connected with a random signal generator (28). 4.The photovoltaic power generation safety monitoring system based on Brillouin distributed optical fiber sensing according to claim 2, characterized in that: The polarization controller (213) is used for adjusting the polarization state of the reference light. The microwave source (215) is used for generating a frequency shift signal to change the frequency of the continuous light in the range of 10-11 GHz. The bias control board (216) stabilizes the output of the IQ modulator (214) according to the intensity of the input light. 5.The photovoltaic power generation safety monitoring system based on Brillouin distributed optical fiber sensing according to claim 1, characterized in that: The optical switch (26) realizes switching of the temperature information of multiple measured optical fibers (27) by controlling the channel parameters. 6.The photovoltaic power generation safety monitoring system based on Brillouin distributed optical fiber sensing according to claim 1, characterized in that: The intelligent photovoltaic panel (61) comprises tempered glass (7), flame-retardant EVA composite layer (8), optical fiber interface (9), photovoltaic cell layer (10), EVA backboard (11), alloy backboard (12), flame-retardant EVA filling glue (13), alloy heating wire (14) and loose tube optical fiber (15). The alloy heating wire (14) and the loose tube optical fiber (15) are laid in the flame-retardant EVA composite layer (8) and used for distributed sensing of the working area temperature of the photovoltaic power generation array (62); The mounting end of the loose tube optical fiber (15) is connected with the optical fiber interface (9) and used for connection with other photovoltaic panels; The mounting end of the alloy heating wire (14) is connected with the partition heating switch (51) and realizes heating control of the photovoltaic panel in different partitions; The output end of the photovoltaic cell layer (10) is connected with the junction box (52) and realizes short-circuit protection of the photovoltaic panel.

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