Photovoltaic Panel Temperature Monitoring And Early Warning Based On Distributed Optical Fiber Raman Sensing

Photovoltaic(PV)power generation is currently one of the main ways to use solar energy.The PV module will be overheated(due to damage,shielding,battery mismatch,etc.),which will cause a serious reduction in the photoelectric conversion efficiency of the module,and even a secondary breakdown of the battery.Therefore,it is of great practical significance to prevent PV modules from high temperature damage and module fire accidents by monitoring the temperature of PV panels.In addition,when the temperature of the PV module is monitored to exceed a certain threshold,cooling measures should be taken immediately.The cooling measures can effectively improve the power generation efficiency of the module.At present,the monitoring methods of PV panel temperature mainly use thermal infrared sensing technology,fiber Bragg grating(FBG)sensing technology and electrical sensing technology,but the above-mentioned temperature measurement methods have some problems,such as low temperature measurement accuracy and inability to realize distributed temperature monitoring,etc.This paper will propose a distributed optical fiber Raman temperature monitoring scheme for PV modules,which can realize distributed temperature monitoring of large-scale PV modules.The specific research work of this paper is as follows:(1)For the monitoring of PV module temperature,the host computer operation interface has been developed,and the distributed optical fiber Raman temperature monitoring instrument has been developed.The performance indicators are as follows: the sensing distance is 11.0 km;the response time is 2 s;the temperature measurement accuracy is±1.00 ℃;the temperature resolution is 0.50 ℃;and the spatial resolution is 1.0 m.The temperature field monitoring experiment results of PV modules show that the local maximum temperature of the modules reaches 39.30 ?C.In addition,the maximum temperature differences,which due to the changes of radiation intensity,dust thickness and inclination angle,are 9.58 ?C,3.01 ?C,and 3.99 ℃,respectively.Through comparative analysis of the component temperature field under different gray layer coverage,different inclination angles,and different radiation intensities,it is concluded that the component temperature increases with the increase of the gray layer thickness and radiation intensity,and decreases with the increase of the inclination angle.Through comparative analysis of the component temperature field under different gray layer coverage,different inclination angles and different radiation intensities.It is concluded that the module temperature increases with the increase of the gray layer thickness.The module temperature increases with the increase of the radiation intensity.And the module temperature decreases with the increase of inclination angle.(2)In order to solve the problem that the current distributed Raman temperature measurement system cannot predict and alarm in the temperature monitoring of PV components.This paper proposes a fuzzy temperature difference threshold advanced warning technology based on fuzzy theory.It solves the problems of low prediction accuracy of traditional early warning schemes and poor real-time early warning,which are caused by problems such as changes in the external environment and large amount of data processing.The experimental results show that the average absolute error of the predicted temperature is1.08 °C,and the fluctuation range of the predicted error is ±3.70 ?C when the system window base is set to 2.