An Online Free Penetration Multi-Stage Fuse Saving Protection Scheme in Distribution Systems with Photovoltaic Sources

In this paper, a multi-stage protective scheme is proposed to maintain the fuse and reclosers coordination. The proposed method operates online and proportional to the photovoltaic sources penetration rate. In the first step, a non-standard Current - Time - Voltage curve is used for fuse saving. If the new calculated TDS from the first stage is not implementable to the reclosers, the second stage of the protection scheme will be activated, and the fault current contribution of photovoltaic sources decrease proportional to inverter PCC voltage. It should be noted that the proposed method is a combitionary method that in the first step, the effect of reclosers sensitivity in modifying the reclosers fast characteristics is taken into account in compared to other schemes presented in this regard, and in the second step, there is less limitation on the output power of PV sources under fault conditions than other inverter current control presented equations. It It is noteworthy that in order to implement the proposed protection method, there is no need to telecommunication infrastructure. The ETAP software simulation results validates the proposed scheme effectively.