Cloud Variance Impact on the Voltage and Power Flow of Distribution Networks with Photovoltaic Generators

The present paper aims to investigate the effect of different types of clouds on the photovoltaic power generators and electricity distribution network in which they are connected. The developed methodology classifies solar irradiance data according to the GOES-13 satellite image processing, which contain information regarding the types of clouds. The image processing results are then compared with real solar irradiance data in order to analyze the influence of shading and thus classify the measured data as: clear sky, partly cloudy and cloudy. The OpenDSS software is employed for simulating the varying generation and load profiles using the IEEE 34 bus system as a testbed. The result analysis shows the power flow and electrical losses, as well as the generation profiles impact on voltage levels and the operation of voltage regulating equipment. Voltage fluctuations and tap changes are also analyzed considering different tap delays.