Impact of Distributed Generation on power distribution system: Over-current protection by phase angle estimation

The increasing use of Distributed generation (DG) in power system has posed some problems along with many advantages. Present distribution system is equipped with non-directional relaying. Due to use of DG the non-directional protection system can mal-operates. Owing to this non-directional over-current protection has become potential research. In this paper apart from discussion on benefits and drawbacks of using DG, a new over-current protection scheme have been implemented which doesn´t requires potential transformer for determining the direction of fault. The new scheme of protection is tested for the dynamic disturbances like change in power angle occurring in the power system.