Optimal siting and sizing of distributed generators to retain the existing protection setup along with their technical and economic aspects

Abstract

Now-a-days, most studies strive towards high penetration of distributed generators (DGs) in distribution systems. Interestingly, the deployment of DGs has the potential to question the selectivity between the relays and also the interrupting capacity of circuit breakers (CBs) upon increased penetration. Furthermore, the integration of DGs leads to sympathetic tripping during faults, which mandates the DGs to be disconnected from the grid, which in turn conflicts the reliability of the distribution systems. Gradually, this facilitates the need for fault ride through of DGs without affecting the security and technical benefits of the system. Hence, to get the best out of DGs and to pull through their challenges, this work optimally sites and sizes the DGs to retain the existing relay settings and CBs and to avoid mal-operations during faults due to reverse power flow along with their potential benefits and their economic impacts. Besides minimising the CB replacements and sympathetic tripping of relays during optimisation of DGs, few fault current limiters are incorporated to avoid these issues completely. Furthermore, this work also explores optimal penetration using a fuzzy logic tool. The proposed methodology is validated for the standard 33 bus radial distribution system using particle swarm optimisation algorithm.