Topology-Diversified Planning-Stage Siting of Grid-Forming Inverters with Post-Event Current-Proxy Feasibility Checks

초록

Grid-forming (GFM) inverters can improve the response of inverter-dominated distribution feeders, but their benefit depends strongly on feeder topology, disturbance location, local voltage support, and converter current capability. This paper proposes a planning-stage GFM siting framework that combines vulnerability-based screening with topology diversification and feasibility checks. Candidate placements are evaluated using a reduced-order phasor-domain planning model with an aggregated frequency-response equation and positive-sequence power-flow checks. The selected placement minimizes a robust base/low-inertia maximum dynamic-security-index objective ( DSImax ) over the selection event set and is subsequently checked using a voltage-adjusted current-capability proxy. The framework is evaluated using disjoint hold-out events, feasible-set comparisons, sensitivity checks, and current-limited power-flow feasibility checks. On the IEEE 33-bus feeder, the proposed placement improves the composite dynamic security index ( DSIcomp ) relative to a topology-only distributed baseline by 4.3%/5.0% on the selection set and 8.6%/8.8% on the hold-out set under base/low-inertia cases. On the high-GFM-penetration simplified IEEE 123-node-derived reconstruction, the corresponding improvements are 0.9%/0.9% on the selection set and 22.0%/22.1% on the five-event hold-out set evaluated in this reduced planning case. For the post-event power-flow snapshots evaluated in this study, the selected placements yield feasible current-limited power-flow solutions under the declared 1.2 pu voltage-adjusted current-proxy constraint, with maximum recorded proxy values of 0.9244 pu and 0.9172 pu in the two test systems. The results support the method as a deterministic planning-stage screening tool with retained verification records; detailed unbalanced electromagnetic, protection, and manufacturer-specific controller validation remains outside the planning-stage model.

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