Communication-Efficient Distributed Online Voltage Control for Sustainable Distribution Networks with High Penetration PV

High photovoltaic (PV) penetration supports low-carbon distribution networks, but reverse power flow can drive radial feeders beyond voltage limits and reduce hosting capacity. Local droop control avoids communication but has limited coordination capability, whereas centralized regulation relies on global measurements and repeated computation. This paper proposes a nonlinear feasibility-recovery distributed online primal–dual Push–Sum framework (NFR-DOPP) for coordinated PV-inverter reactive-power control. The framework combines projected primal–dual updates with sparse directed Push–Sum coordination and a nonlinear recovery term that strengthens correction when voltage constraints become active. An error-compensated Top-k differential compression layer further reduces inter-agent state exchange while preserving the physical feedback loop and projected update. Nonlinear closed-loop simulations on a modified IEEE 123-bus feeder show that NFR-DOPP restores voltage feasibility more effectively than conventional distributed and local droop baselines. Under a 06:00–18:00 dynamic profile, the compressed implementation maintains zero PV node voltage violations and reduces cumulative transmitted bits by approximately 31% relative to full-state communication. A secondary active-loss audit in the tested case indicates that stronger coordinated reactive-power regulation may increase losses. The proposed framework should therefore be viewed as a voltage-feasibility and communication-efficiency method rather than a loss-minimization strategy.