Solar PV and the German/European Electricity Supply Network
The Electricity supply network of Germany is part of the European Common Control Area,ENTSOE. This includes transmission and generation with typical 220 KV and 380 KV system voltages. For cities and small distances 110 kV is used for transmission and distribution. Regional distribution is accomplished over 10 kV and 20 kV 3-phase, 3-wire system. Local distribution uses a 400 V, 3-phase, 4-wire system with a neutral center wire. Nominal voltage between phases and neutral is 230 V.
Typically, buildings are connected to this type of 3-phase system. Internal 1-phase loads are distributed over the three phases. Voltage regulation is regularly performed at the HV/MV transformer through a tap changer.
In the residential areas in Germany the network frequently comprises a transformer with a nominal power of Sn = 400 kVA. This transformer feeds several feeders of 150 mm² Al cables. These cables can carry about 180 kVA continuously /PV Upscale – Utilities Experience.
Off late in Europe a substantial change in Electrical Power Generation and Distribution has been witnessed. The structure is altering from a central, top-down structured generation and distribution to a combined central and decentralized generation. With fast growing potential of photo voltaic power systems (PV) mainly in the low-voltage grid the impact of PV on the whole electricity supply network has been re-assessed. Even the Utilities view it as a major source of electricity generator and can have big impact on the European Electricity Supply Network .
Grid stability is of primary importance. Therefore “fault-ride-through” capability are an important feature for PV systems including small ones, due to their large number. This will help in maintaining the stability of Grid.
Posted By: Prateek Sikka