Topology-Aware Assessment of Voltage Regulation and Continuous Photovoltaic Hosting Capacity in PV-Rich Distribution Feeders with Smart-Inverter Controls

The increasing penetration of distributed photovoltaic generation is changing voltage behavior in distribution feeders and creating operational challenges related to voltage violations, losses, curtailment, and hosting capacity. This paper proposes a topology-aware analytical and computational framework for assessing voltage regulation and continuous photovoltaic hosting capacity in distribution feeders with smart-inverter controls. The framework combines topology-dependent voltage sensitivities, balanced steady-state power-flow simulations, explicit inverter apparent-power constraints, and gain indices that quantify the contributions of feeder topology, inverter controls, and their interaction. The IEEE 33-bus and IEEE 69-bus feeders are evaluated under radial and meshed configurations, heavy- and light-load conditions, and four photovoltaic operation modes: no control, Volt–Var, Volt–Watt, and combined Volt–Var/Volt–Watt control. A discrete sweep from 20% to 150% PV penetration is used to characterize voltage, active and reactive losses, and curtailment trends. Hosting-capacity boundaries are subsequently determined through an interval-aware procedure consisting of a one-percentage-point scan followed by bisection refinement to 0.1 percentage point, without assuming a globally monotonic feasibility transition. The results show that the feeder topology strongly affects voltage sensitivity and photovoltaic hosting capacity. The meshed operation generally increases voltage margins, while the interval-aware assessment identifies nonzero feasible penetration ranges, even when the zero-PV operating point is constrained by undervoltage. Volt–Watt achieves the largest hosting-capacity gains at the expense of curtailment, whereas Volt–Var preserves photovoltaic injection but may increase feeder losses. Therefore, hosting capacity should be interpreted jointly with topology, inverter controls, injected power, curtailment, and losses.