Optimal Placement and Sizing of Distributed Generators to ensure Protection Coordination

Thanks to the mammoth benefits, integration of Distributed Generators(DGs) is becoming attractive in distribution systems. Penetration of DGs changes the unidirectional structure of radial systems, leading to reversal of power flow. However, the existing relays are non-directional and hence operate based on the magnitude of the short circuit current. This leads to mal-operation of the relays if left un-attented to, even though for low penetration levels, the effects are negligible. This work addresses this issue by optimally sizing and siting the DGs in the non-autonomous micro-grids. Hence a huge investment cost needed to replace the existing relays is saved. The optimal sizing is done considering the installation and fuel cost of DGs using the particle swarm optimization algorithm and the optimal siting is done analytically using ETAP software. MATLAB is used to solve the PSO algorithm. Standard 33 bus test system is used to validate the proposed algorithm.