Analyzing Performance of Distance Relay in Protecting Distribution Lines with Distributed Generation

摘要

Distance relays can be a suitable protection relay for distribution lines. It could replace the commonly known overcurrent based relays that experience drawback performance due to installation of distributed generation. However, the capability of distance relays for working on distribution line is not known very well. Therefore, this research was conducted in order to have a clear picture about the performance of distance relay on distribution lines that having distributed generation. The research is conducted by simulating distance relays on distribution lines using Digsilent Powerfactory 2017. Capability of the relays was tested for four types of faults (phase and earth faults), each of them with bolted and resistive faults and remote infeed effects. From the simulations have been found that distance relays work correctly for all network condition, i.e. grid connected, islanding operation and DG disconnected. Distance relays also coordinate correctly with over current relays. However, the relays suffer incorrect operation due to fault resistances and remote infeed effect from distributed generation.