Modeling and measurement of small Photovoltaic systems and penetration scenarios

The operation of photovoltaic (PV) units connected to the system is characterized by several uncertainties due to the number of running units, the points where these units are sited, the exported power and the injection of harmonic currents. The objective of this paper is to investigate the penetration level of PV units in the low voltage (LV) network. Starting from field measurements a model has been created for the computation of harmonics and voltages in the grid. The PV unit is modeled as a DC voltage source connected to the network via electronic switches, representing the PV inverter. Simulations were performed in the simulator packages PSIM^copy and Harmoniques^copy. Results from the simulated model agree with the results obtained by the measurement campaign. Following this the acceptable penetration level of PV systems in the LV distribution network is investigated for several scenarios, referring the number, the locations and the operation of the units.