Study On The Pollutant Impact On Performance And Power Degradation Of Photovoltaic Modules

Photovoltaic module is the basic unit of the photovoltaic power generation.The output characteristics of photovoltaic modules and service life are the two most important problems in the research of photovoltaic(PV).And more centralized photovoltaic power station construction in our country is built in the western desert region,where the climate environment is relatively poor and the sand dust.PV modules in the area are in the overlying-ash state.Through to the actual survey on the Gonghe and golmud photovoltaic power station,we found that the overlying-ash problem can make the big discounts of the output characteristics and the service life of photovoltaic modules:(1)The overlying ash block out the sun,affecting the component output power and output characteristic directly;(2)The overlying ash provide channels for leakage current,which increase PID power attenuation,leading to reduce component life indirectly.According to these two issues,this article has carried on the following research work:(1)The research of the relationship between the overlying ash and the output parameters of photovoltaic modules.In order to deduce the theory model of quality and the output characteristic,we introduces the transmission spectra of dust,and integral different wavelengths of the sun's rays to get the equivalent solar power received by modules,combined with the Overlapping Theory proposed by NASA.Using traditional photovoltaic modules output model,we deduce the output performance and output power,etc.In the laboratory,the simulate experiments is conducted,to verify the accuracy of the model and the theory.(2)The research of the relationship between the overlying ash and the leakage current.In the environment box,we carry out the simulation of ash and salt overburdened on PV modules,to measure the leakage current under different conditions,and to summarize the relevant laws.This paper analyzes the reasons of leakage current changes.The Peck leakage-current-equation are under correction by using the experimental data,to get the leakage current model of photovoltaic modules in the condition of overburden of ash and salt.(3)The research of the relationship between the overlying ash and PV module power attenuation.For deriving the power attenuation model under the condition of the overlying ash,we introduce the activation energy Ea as the parameters,to relate the leakage current and the power attenuation model.And we get detailed analysis of the effect mechanism of ash on power attenuation.Finally,in the environment box,we accelerate the attenuation of the PV module in the experiment,to verify the accuracy of the models.The article analyzes the effects of dust from two aspects: the output characteristics and aging attenuation of photovoltaic modules.In the laboratory,we carried out the related experiments,summarized overlying-ash-modules characteristics,and deduced the corresponding formation models.This study analyzes mechanism of the influence of overlying ash on photovoltaic modules,and creates a new precision formation model of output characteristic and power attenuation of PV modules in desert and heavy pollution area,provides a theoretical basis and provide a theoretical reference for photovoltaic power station cleaning work.