DocumentCode :
683352
Title :
Comparing PV power plant soiling measurements extracted from PV module irradiance and power measurements
Author :
Gostein, Michael ; Littmann, Bodo ; Caron, J. Riley ; Dunn, Lawrence
Author_Institution :
Atonometrics, Austin, TX, USA
fYear :
2013
fDate :
16-21 June 2013
Firstpage :
3004
Lastpage :
3009
Abstract :
The accumulation of dust and other environmental contaminants on PV modules, also known as PV module soiling, is a significant source of lost potential power generation for PV installations. Designers and operators of utility-scale solar power plants are increasingly seeking methods to quantify soiling-related losses, in order to improve performance modeling and verification or to optimize washing schedules. Recently, soiling measurement equipment has been introduced based on the measurement of two co-planar PV modules, one of which is regularly cleaned, and the other of which naturally accumulates environmental contaminants. These measurements are used to determine a soiling ratio (SR), which may be applied as a derate factor in analysis of the PV system performance. In this work, we examine the difference between a soiling ratio metric calculated from measured temperature-corrected short-circuit current values (SRIsc), which represents the fraction of irradiance reaching the soiled modules, versus a soiling ratio calculated from measured temperature-corrected PV module maximum power values (SRPmax), which represents the fraction of power produced by the soiled modules compared to clean modules. We examine both techniques for CdTe and c-Si module technologies. This study is motivated by the fact that variations in module efficiency versus irradiance, as well as any non-uniformity of soiling, may introduce differences between the power losses estimated from short-circuit current values versus actual soiling-induced power losses. For CdTe, the SRIsc method is found to be a good proxy for the SRPmax method for nonuniform soiling levels up to 11%.
Keywords :
II-VI semiconductors; cadmium compounds; dust; elemental semiconductors; photovoltaic power systems; power measurement; short-circuit currents; silicon; solar cells; tellurium compounds; CdTe; PV installations; PV module irradiance; PV power plant soiling measurements; PV system performance; Si; co-planar PV modules; dust accumulation; environmental contaminants; nonuniform soiling levels; performance modeling; performance verification; power measurements; short-circuit current values; soiling measurement equipment; soiling ratio; soiling-induced power losses; soiling-related losses; temperature-corrected PV module maximum power values; temperature-corrected short-circuit current values; utility-scale solar power plants; washing schedules; Current measurement; Pollution measurement; Power generation; Power measurement; Soil measurements; Temperature measurement; dust; measurement uncertainty; module soiling; performance analysis; photovoltaic systems; solar power generation;
fLanguage :
English
Publisher :
ieee
Conference_Titel :
Photovoltaic Specialists Conference (PVSC), 2013 IEEE 39th
Conference_Location :
Tampa, FL
Type :
conf
DOI :
10.1109/PVSC.2013.6745094
Filename :
6745094
Link To Document :
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