Solutions for Voltage Sags During Distributed Generation Anti – Islanding Protection

Abstract: In this paper, solutions to the problem of voltage sags caused by distributed generators anti-islanding protection are proposed. In a system with both substation and Distributed Generator (DG) supplying in parallel to a load, during any temporary fault condition, the DG will be disconnected from system by anti –islanding protection. After the reclose operation, the whole power has to come from the substation since the DG is no longer present and due to this there is voltage sag at the load end. This problem can seriously affect power quality indices as well as distributed generators reconnection procedure. In this context, this work investigates several potential solutions to be adopted by the utility or the DG owners and presents a thorough evaluation of their main advantages and disadvantages. The presented studies and procedures will guide the utility engineers in the making decision process associated to the choice of reasonable mitigation techniques to this problem. Solutions are simulated using ETAP 12.0 tool and HIL typhoon SCADA software. Certain solutions are simulated by developing a hardware prototype. The results obtained were compared and analysed for the better understanding of the stated solutions.

Keywords: Anti-islanding, Reclosing operation, Voltage sag