Photovoltaic power plants contribution to the flicker level in the medium voltage energy network. Case study

In recent years, renewable energy sources, particularly photovoltaic power plants, have become important sources of energy for the National Energy System in Romania. Connecting them to the energy grid may cause frequency variations or fast voltage variations (flicker), significant problems in terms of power quality. The severity of these problems depends directly on the percentage of the photovoltaic system integration, geographic location and grid typology. In Romania, photovoltaic power plants that are connected to the medium voltage networks must comply with legislation (NT. 30, Ord. 74, Ord. 59, NT E 012, EN 50160). Given these aspects, this paper aims to conduct a study on the contribution of photovoltaic power plants regarding the flicker level in the medium voltage network; in this particular case, a 5 MW PV plant is presented.