Analysis of Shading Effects in Solar PV System

Abstract

Due to its advantages, the use of clean energy in general and especially solar PV systems offer a great solution to problems that people face in their everyday life. Generation of energy using solar PV system technology is cheaper and clean technology compared to one of the fossil fuels. Aside from its advantages, this technology still has some drawbacks that affect its performance where the ones caused by shadows are considered as one of the big problems. This research work showed laboratory experiments and simulations to see how the system is affected by shading where a 1.5 kWp PV system has been used for the study. The system has been simulated with PVsyst (7.0.6 version) and experimented within the University of Rwanda/ African Center of Excellence in Energy Studies for Sustainable Development (UR/ACE-ESD) High E-Tech Smart Grid Laboratory. Laboratory experiments showed that whatever shade is applied to the system, the DC voltage and current change (increases or decrease) and DC power decreases. In the simulation, it has been notified that the irradiance losses are dependent on the time of a day, sun position, and the rate of created shadow. From the simulated results, annual energy produced and near shading losses in the non-shaded system is 2373 kWh and 0% respectively while in the shaded system, the annual energy produced was 2055 kWh and 2.1% of near shading losses. This undoubtedly disturbs the performance of the power system as well as other related works. Based on the result for this work, shadow affects the performance of PV systems and the rate at which the PV system is affected depends on the shaded area, position, and how much radiation reaches that shaded area. This increases the system’s instability as it can lose its ability to generate power at the maximum due to the user control algorithm as well as degradation of the output that a PV panel can produce. Furthermore, investigations need to be carried out to modify this work. Providers of energy based on solar systems should sensitize shading issues towards their beneficiaries, and make a follow-up to installed systems so that users can give special attention to shading issues while they operate their system. It is recommended to continue this research within Rwandan Solar power plants considered as a case study for more investigation.