Unsymmetrical Fault Analysis of PV for Different Transformer Configurations

Modular nature, less geographical constraints, low maintenance requirement and the ease of implementation make Photovoltaic (PV) based electricity generation more favorable than other solar power based generation, especially for a load-side generation. Hence, in recent times the PV based microgrids both DC and AC has turned up as a new way to meet the load demand. However, the increased generation from the PV sources has also raised some protection issues due to its limited reactive power capability and low fault current contribution. Furthermore, the transformer configuration used after the PV inverter also affects the fault current behaviour of it during the fault such as the voltage level of the healthy phases and the propagation of the effect of fault will depend upon the transformer configuration during unsymmetrical fault. In this paper, we have thoroughly performed the unsymmetrical fault analysis of the PV on a standard IEEE 10-bus system on DigSilent/Powerfactory and has also studied the effect of different transformer configuration on it.