Comparative Annual Energy Yield of Total Cross Tied-in- Series and Conventional PV Array Configuration Under Unshaded and Partial Shading Conditions in Urban Areas

(PV) technology has great potential for electricity generation in an urban environment. Urban areas are characterised by the presence of high-rise buildings, trees, chimneys and other structures, the shadow of which becomes unavoidable for the installed PV arrays in their neighbourhood. Generally, it is not possible to remove or relocate such structures in the vicinity of the PV system. Such persistent partial shadings can result in a significant loss in the annual energy yield the of PV array. To get the desired energy yield, the installation of more PV modules would be required which implies a higher cost of electricity for the end users. The present work compares the annual energy yield and DC performance ratio of total cross tied in series or TCT-S PV array with the conventional array under unshaded and five partial shaded conditions. The first part of the work comprises experimentally measuring current-voltage curves for both the arrays at different operating temperatures and irradiance in real outdoor conditions for several days. The outdoor data is used to generate 22-element maximum power (Pmax) matrix as per IEC61853-1, for both the arrays under unshaded and partially shaded conditions. The second part of the work comprises numerically estimating the energy yield of both the PV arrays (normalized to 1kW system) under each scenario using their respective Pmax matrix, weather data obtained for one complete year for the location and the translation equations. It is found that a significant enhancement of annual energy yield ranging from 4.8 % to 36.7 % under partial shadings can be obtained by the TCT-S array over the conventional array.