I. Introduction
The conventional power systems have changed by the addition of power generation sources, such as photovoltaic (PV) system, in the distribution systems due to environmental issues, rapid response to high demand, proximity to local loads, increase of the system reliability, etc [1], [2]. This new system configuration has been challenging the monitoring, control, and protection system. A relevant parameter in this new system configuration is the impedance. In the control systems, the variation of the impedance in the network can be used to investigate and improve the operation of the system by the injection of active or reactive power [3]. In protection systems, the impedance estimation has been presented as an alternative to detect problems in the grid, such as islanding and ground faults [4]. Therefore, the correct impedance estimation of the grid is a useful tool for the best performance in this new system configuration.