A new approach for voltage sag source relative location in active distribution systems with the presence of inverter-based distributed generations

The growing penetration of distributed energy resources (DERs) in form of inverter-based distributed generations (IBDGs) in distribution systems has a high impact on fault location methods. Therefore, traditional fault relative location schemes need to be extensively investigated. This paper presents a study on the fault response of synchronous-based distributed generations (SBDGs) and IBDGs. The analysis is based on models of DG for the periods before and during voltage sags. The examination of the two kinds of DGs shows how the fault response of IBDG can have a negative effect on methods for voltage sag source location that use current measurements, i.e. current-based methods (CBMs). On the other hand, from the perspective of the IBDG owner, it is important to know if the source of the voltage sag is within his power system or not. Therefore, a improved method (ICBM) of the existing CBM, that uses the parameters of the inverter controller system of IBDG (threshold current and saturation current) and the positive sequence power factor, is proposed. The previous CBM, as well as the ICBM, are evaluated by applying numerical simulations. The results show very good accuracy of the proposed method in systems with a single IBDG or multiple IBDGs.