The Impact of Multiple Small PV Units on Distribution Networks. Romanian Case-study

The paper presents the results obtained at the end of a study whose main goal was to answer the question: What will happen in a distribution network if there will be a large injection of power from a big number of small PV units? This situation is typical for rural distribution networks where the domestic consumers have their own PV generation units, thus becoming prosumers. The study began with the modeling of the usual domestic consumer from rural regions. After this step being finalized, the implementation of the distribution network in a simulation software followed. For this stage MatLab/Simulink was used. Thus, different situations were simulated in order to determine a full understanding of the possible problems that can appear, and consequently to be able to take the proper actions to minimize the negative impact. The results of the simulations show that in a typical summer day, when the PV units produce electricity at 100% of their capacity and the loads' consumption is the lowest, the voltage in the point of injection in distribution network can reach values that will determine the faulty operation of the pronsumers due to the protection apparatus' activation. Various configurations for the grid have been considered. Also, the study points out that integrating PV units by residential consumers can also help the electric grid to better maintain voltage variations in cases of larger distribution lines.