Characterization of Distribution Grid Operation after Connection to Distributed Power Supplies

With a large number of distributed generation (DG) sources connected to the distribution grid, their impact on grid operation is significant. This paper analyses the PV and wind turbine output characteristics and the impact of DG integration on distribution network voltage, losses and harmonics through modelling and simulation. Light and temperature have a significant impact on PV output; wind turbine output varies with wind speed. Integration location, capacity and mode are important: central access has the least impact on voltage; reasonable capacity (1-1.5 times load) reduces losses, but if more than 2 times, losses increase. Grid terminals are very sensitive to harmonics due to high impedance; cluster integration may lead to total harmonic distortion above the norm (e.g. $5.5 \%$ at 900 kWh). This study provides guidance for rational DG integration and distribution network planning.