Optimal placement and size of Tap Changer Voltage Regulator in Distribution system using Hybrid GA PSO

Modern distribution networks increasingly employ voltage regulators to regulate voltages within legal limits through the growing penetration of distributed energy resources (DERs) and variable loads. In this study, we develop and validate an optimization framework for single stage, on load tap changing (OLTC) voltage regulators across two canonical radial feeders (IEEE 33 and IEEE 69). The objective of the study is to minimize active power losses across regulators, while still keeping the voltage in acceptable limits (0.95 − 1.05 pu at each bus). The regulator is modeled as a discrete tap transformer, and the optimization framework Hybrid GA PSO implemented in Python PyCharm community 2025 environment simulation for its powerful and flexibility in optimization. Full power flow simulations are conducted under both the base case and optimized tap settings for both systems. On the IEEE 33 feeder, optimizing the tap at bus 2 from unity to 1.0164 reduced active losses from 211.0 kW to 156.21 kW and raised the minimum bus voltage from 0.9038 pu to 0.9974 pu, while the maximum voltage increased from 1.000 pu to 1.200 pu. Similarly, on the IEEE 69 feeder, tuning the regulator at bus 45 to a tap ratio of 1.0198 cut losses from 225.0 kW to 161.19 kW and improved the voltage envelope from 0.9092 1.000 pu to 0.9592 1.19999 pu. These enhancements were achieved with minimal hardware adjustments and without violating operational constraints. Future work will apply this process to meshed and renewables rich grids, while considering stochastic load and generation forecasts to assist with real time implementation.