A Local measurement based protection technique for distribution system with photovoltaic plants

Abstract

Inverter interfaced distributed generation units contribute limited fault current and thereby the current magnitudebasedprotection schemes find limitation for such situations. Change in penetration level of renewable energy sources with timemakes available protection schemes more challenging. The distinction between load and fault current is an issue and with highresistance fault, level of fault current and load current becomes comparable. In this paper, local measurement-based protectiontechnique is proposed that uses current and voltage signals to derive accurate protection decision for a distribution system inthe presence of distributed generation units. The method uses real and reactive power calculated at the relay point for thedecision. The performance of the algorithm is tested for a 33 bus distribution system simulated using DIgSILENT PowerFactory.Considering such units, the method is tested for both islanded and grid-connected modes, the varying level of distributedgeneration penetration and for different fault resistances. The results demonstrate the strength of the proposed method overavailable techniques. The proposed method is also validated using hardware-in-loop testing using Arduino NANOmicrocontroller and OPAL-RT simulator in real-time.