Sag Estimation of Real Transmission Systems for Faults Along the Lines in the Presence of Distributed Generation

In this paper, the influence of the distributed generation on the severity of the voltage sags (dips) caused by the three phase short circuits along the feeders was considered. For obtaining the voltage sags, we used the fault position method (FPM). The paper demonstrates that the FPM involves acceptable accuracy with reduced computational efforts. This paper, in particular, deals with the effects of the units of the distributed generation on the quality of the voltage in the HV networks. The considered units are connected to the transmission system by means of HV/MV stations, and the severity of the dips through the transmission system was assessed in different generation scenarios. The numerical applications refer to a part of a real transmission system using actual data of the transmission system operator (TSO).