Impact of renewable energy penetration on the Greek distribution network

This paper aims to assess the impact of renewable energy penetration on the Greek distribution network. The assessment is performed by using four operation scenarios, characterized by different consumption and generation conditions. To this end, a load flow analysis with typical consumption and generation data is executed and used as a benchmark, whereas the load flow results of the other operation scenarios are compared with the ones of the benchmark case. The comparison is conducted in terms of maximum voltage and possible upper voltage violations, active power losses, active power absorbed, active power generated, and total current in the beginning of the feeder (magnitude and direction, since in some cases there may be inverse power flow from the distribution network to the transmission system). The validation of the results, together with numerical evaluations, are carried out by using a real distribution network feeder of the Greek Distribution System Operator as well as real measurements as input in the load flow analysis. As a further contribution, the paper investigates possible correlations between alarms for instant upper voltage limit violations and the day of the week, the hour of the day, and the typical profile of generation of solar photovoltaic units.