DESIGN OF THREE-PHASE AUTO-RECLOSURE RELAY FOR 33 KV TRANSMISSION NETWORK USING A FUZZY LOGIC APPROACH
This paper investigates the limitations of conventional fixed dead-time auto-reclosing schemes and proposes a fuzzy logic–based auto-reclosure relay (FL-ARR) for 33 kV transmission networks to improve system reliability and operational continuity. Conventional auto-reclosure employs a single fixed dead time irrespective of fault type and location, resulting in suboptimal reclosing decisions, unnecessary delays in service restoration, and increased customer interruption—particularly for transient faults that could be swiftly cleared. Moreover, the inability to distinguish between transient and permanent faults leads to repeated supply disruptions and elevated circuit-breaker maintenance costs. The study aim is to design and simulate 3phase intelligent autoreclosure relay capable of determining optimal reclosing dead time based on fault type and location. A Mamdani fuzzy logic–based auto-reclosing scheme with an intelligent decision mechanism was developed and modelled in MATLAB/Simulink. The fuzzy logic controller dynamically determines the optimal reclosing dead time by intelligently classifying fault types under four scenarios—Line-to-Ground (L-G), Line-to-Line (L-L), Double Line-to-Ground (2L-G), and Three-Line-to-Ground (3L-G)—at multiple feeder locations. Simulation results demonstrate that the proposed scheme reduces dead time for transient faults from 230 ms to 100 ms, a reduction of approximately 52–56%. These results confirm that the FL-ARR enhances reclosing success rates, minimizes unnecessary breaker operations, and reduces equipment stress—offering a practical and validated solution for improving reliability in medium-voltage transmission networks. It is recommended that additional research should be extended to larger transmission network such as 330kv double circuit voltage level that is close to generating station.
Authors : Hamza, Y.A., Musa, S.Y., Visa, I.M. and Aminu, M.
Category : Open Access Volume (Issue) : 12(1) Date Uploaded : 5th August 2026