ANALYSIS OF VARIABILITY IN POWER GENERATION FROM SOLAR PV SYSTEM

Abstract

Solar power generation has been growing over the past years at a very fast rate. It has become one of the key mediums of Renewable Energy utilization. Renewable Energy like wind and solar energy are variable generation resources which depends on various factors. In case of solar energy generated from solar photovoltaic cell, the movement of sun makes the value of PV output variable. This type of variation is known as diurnal variation which repeats after every 24 hours. The solar PV output is intermittent too because of uncertain climatic condition like clouds which sometimes reduces output to zero. The variability of solar PV causes various problems like load generation imbalances and frequency fluctuation issues which ultimately affects the grid integration of solar energy. The variability of the solar energy resource is one of the important factors that demotivates individuals and companies from mass adoption of solar energy. It is therefore important to study the variability of solar energy and devise mitigation strategies for maximizing its utilization. In this research, the variability is studied using wavelet variability model. This model decomposes the normalized power output time series into different frequencies using the wavelet transform. Thirteen months of approximately 1-minute and 2-minute time resolution data from these utility scale PV plants separated by a maximum distance of 512 km was used for analysis. This study analyses the scope of geographical smoothening achieved by integrating the solar photovoltaic generation of different plants located at a range of distances between each other. It also quantifies the spatial and temporal nature of variability with the help of different wavelet modes representing different frequencies. This will help the grid operators in effectively mitigating the challenges of solar resource variability and better integration of solar energy with the grid.