ADBO-Optimized Smart Inverter Integration of PV/BESS for Incremental EV Charging Capacity Without Further Voltage Degradation on a Gaborone-Oriented IEEE 69-Bus Surrogate Feeder

This paper presents a scenario-based, Gaborone-oriented surrogate-feeder study using a modified IEEE 69-bus radial test feeder remapped onto representative Gaborone urban functional zones, to test whether coordinated siting and control of EV charging stations (EVCS), photovoltaic (PV) generation, and battery energy storage (BESS) can increase the EV charging load a feeder accepts without further degrading its already non-compliant evening-peak voltage (below the ANSI C84.1 0.95 p.u. limit even before any EVCS, PV, or BESS is added). The capacities reported are therefore incremental no-further-degradation capacities rather than standard feasible hosting capacities and should not be read as utility-specific EV connection limits. Four scenarios are examined: an uncoordinated baseline, unmanaged PV/BESS addition, Adaptive Dandelion Optimizer (ADBO)-based joint siting/sizing of EVCS, PV, and BESS with smart-inverter Volt-VAR/Volt-Watt control, and stochastic/high-penetration stress testing. Uncoordinated PV/BESS addition is found to introduce a separate midday overvoltage and reverse-flow risk without resolving the pre-existing undervoltage. Coordinated ADBO-based siting adds substantial incremental EVCS capacity without further lowering the minimum voltage, and Volt-VAR control adds further support at the evening peak by using otherwise-idle nighttime PV inverter capacity; neither intervention achieves full statutory compliance. A stochastic cloud-transient test also reveals a rapid substation power ramp that a voltage-compliance check alone would miss. ADBO is benchmarked against PSO, a real-coded GA, and GWO: it reaches a comparable best-case objective value but is less consistent across runs and converges more slowly, so it is presented as a tested candidate rather than a demonstrated superior method. The principal limitation of this study is that the feeder, load, irradiance, and algorithm-comparison data are a transparent surrogate and sensitivity analysis rather than measured utility data; the results should accordingly be interpreted as a methodological demonstration of coordinated EVCS-PV-BESS planning rather than a validated assessment of Botswana Power Corporation’s Gaborone network.