Multi-objective Bacterial Foraging Optimisation of On-Load Tap-Changer Operations for Voltage Regulation and Loss Reduction: Evidence from the IEEE 30-Bus System and a Nigerian 63-Bus Feeder (Published)
This study evaluates a bacterial foraging algorithm (BFA) for coordinating on-load tap-changer (OLTC) settings with two operational objectives: reducing bus-voltage deviation and limiting tap operations. The method was assessed using a standard IEEE 30-bus test system and the 63-bus Government Reserved Area (GRA) feeder in Bauchi, Nigeria. Network power-flow calculations were conducted in MATLAB R2019b with the PSAT toolbox, and the BFA search was configured with four bacteria, ten chemotactic steps, four swim steps, four reproduction steps, two elimination–dispersal events and a 0.1 run-length parameter. The reported IEEE 30-bus results show active losses declining from 17.528 to 15.710 kW (10.37%), reactive losses from 68.888 to 61.340 kVAr (10.96%), voltage deviation from 0.9477 to 0.7115 p.u. (24.92%), and daily tap operations from 17 to 11 (35.29%). For the Bauchi GRA feeder, active losses declined from 171.65 to 113.56 kW (33.82%), reactive losses from 129.59 to 98.76 kVAr (23.79%), voltage deviation from 0.6900 to 0.6420 p.u. (6.96%), and tap operations from 22 to 14 (36.36%). The findings indicate that BFA-based OLTC scheduling can improve the reported loss and switching indicators across a benchmark network and a field-derived Nigerian feeder. Interpretation is constrained by inconsistencies in the source thesis concerning voltage limits, the definition of voltage deviation, and some reported percentage improvements. The results should therefore be treated as simulation evidence requiring reproducibility checks, sensitivity analysis and validation against time-varying feeder measurements before operational deployment.
Keywords: Nigerian distribution feeder, On-load tap changer, active power loss, bacterial foraging algorithm, distribution network, reactive power loss, tap-operation minimization, voltage regulation