SC Currents Minimization in Distributed Generation Embedded Distribution Networks with Optimal Application of FCLs

For meeting the increased demand of electrical power, distributed generation (DG) based on renewable energy resources (RERs), has become a potential alternative to large plants based on fossil fuels. The power from environmentally friendly RERs is available at a competitive price due to technological advancements in recent times. Moreover, optimal allocation of DG at the distribution network (DN) level may result in power loss reduction, improvement in voltage profile and the network's overall reliability. However, integration of DG may increase the short circuit (SC) level beyond the capacity of the protection gear, conductors, transformers and other components of a DN. The high short circuit currents (SCCs) may be reduced by application of a fault current limiter (FCL). However, most of the existing literature proposes optimization of FCLs size by considering only normal configurations of a DN. This approach is inappropriate as it may fail to produce the desired reduction in SCCs in different $N - 1$ contingency scenarios. In this paper, a new strategy is presented that considers both normal as well as various contingency situations for optimal allocation of FCLs in a DN with DG connection. The strategy is implemented in the IEEE 30-bus system in a MATLAB environment using a genetic algorithm (GA). The simulation results prove that the proposed strategy is effective in determining the optimal FCLs size that restricts the SCCs to a safe level in different operating conditions including $N-1$ contingencies and thus, improves network safety and reliability. The strategy described in the paper can play an important role in DN planning involving optimal application of DG and FCLs.