Photovoltaic systems aggregation using wavelet analysis: A case study

The variability in the power output of grid-tied PV system becomes challenging especially in high penetration scenarios. The analysis of the variability of aggregated PV system becomes important for distribution planning, and development of mitigation strategies. Several methods have being proposed to analyze the variability of aggregated PV systems. The use of wavelet analysis is fast becoming a technique for analyzing the variability of aggregated PV systems. This paper presents a case study of the aggregation of the real data of the power output of four PV sites located in Florida. A wavelet design and correlation study for the PVs under case study is presented. The discrete meyer (which matches the designed wavelet) is used to analyze the variability of each PV fleet, the aggregation of pairs of the PV plants and the aggregation of entire four PV fleets. The impact of the distances (analyzed by Global Horizontal Irradiance (GHI) correlation) and the respective sizes of the PV fleet is also presented. The results showed how the differing power output profile with their correlation values produced different reduction in variabilities of the aggregated sites. Also, with pairs of PV fleets, more reduction in variability is achieved with PVs with similar sizes. The higher the number of aggregated PVs, the more the reduction variability of the aggregated PV power output.