DESIGN OF A FUZZY LOGIC BASED ADAPTIVE PROTECTION SCHEME IN DISTRIBUTION NETWORKS WITH DISTRIBUTED GENERATION

Abstract

Integration of renewable energy-based DG in power systems has become an active research area for the last few decades due to various economic, environmental, and political factors. The integration of DGs brings several challenges even if it offers many advantages. Power system protection is one of the major issues of integrating DGs into an existing distribution network. Besides increasing fault current level of the system caused by the interconnection of the DG, Integrating DG causes the system to lose its radial power flow. The loss of coordination between primary and backup relays is one of the disadvantages of integrating DGs, since traditional relay settings may fail or work incorrectly under new conditions. Hence, new protection schemes able to maintain protection coordination are strongly needed in distribution networks with a significant integration of DGs. In distribution systems with renewable energy-based DG penetration, the fault levels are intermittent and continuously changing as per connection of DG. In this study, adaptive protection scheme in distribution networks considering intermittency of DG using a fuzzy logic controller was proposed. The controller chooses the best time multiplier setting (TMS) of the relay depending on the size of the DG connected. IEEE 13 bus radial distribution network was used and ETAP software was used to model the network and do load flow and short circuits analysis which are necessary for setting and coordination of overcurrent relays. Fuzzy logic toolbox of MATLAB was used to design the fuzzy logic controller. It was seen that the use of fuzzy logic based adaptive protection scheme mitigates the impact of integrating DG on protection coordination in the distribution network.