Faults Location Variability in Power Distribution Networks with High PV Penetration Level

The penetration of photovoltaic (PV) generation into transmission and distribution power systems is rapidly increasing in Brazil. As the actual scenario presents a low PV penetration level, the main protection devices, such as the distance/impedance relays (DIR), maintain network reliability without the need to change its parameters. However, the impedance, measured by DIR, may significantly change in a high PV penetration scenario, impacting on faults location. This paper reports the variability of impedance measured by a power substation DIR under a high PV penetration on grid. Computer simulations were conducted on IEEE 13-Node Radial Test Feeder with 56.2% of PV penetration level. The PV generators (PVG) were configured to respond to high-voltage ride-through (HVRT) and low-voltage ride-through (LVRT) conditions, following the regulation of Brazilian National Electrical System Operator (ONS). The simulations were carried out changing the fault type, location and the connected or disconnected status of PVG along the feeder. The results shows that three line-to-ground (3LG) and single line-to-groud (1LG) faults, in this PV scenario, can influence the faults location by 10.8%. Also, the impedance variability for ILG faults is, in average, almost three times greater than 3LG faults. These results highlight the need for an adaptation of the protection parameters in this new scenario.