Coordinated Planning of Distribution-Side Distributed Generation and Energy Storage Considering Transmission–Distribution Coupling

Against the backdrop of the dual carbon goals of carbon peaking and carbon neutrality and the increasing penetration of renewable energy, conventional hierarchical planning methods for transmission and distribution networks are becoming insufficient to accurately characterize power exchange, boundary-voltage feasibility, and reserve support at the point of common coupling (PCC). This may lead to mismatches between distribution-side generation–storage planning decisions and actual system operating boundaries. To address this issue, this paper proposes a coordinated planning method for distribution-side distributed PV generation and energy storage that accounts for transmission–distribution coupling. First, the PCC is modeled as the physical interface between the transmission and distribution networks, and power-exchange balance, boundary-voltage feasibility, and interface-capacity constraints are introduced to transform traditionally exogenous boundary conditions into endogenous constraints. Then, a multi-objective planning model is developed to minimize annualized investment cost, operating cost, and PV curtailment rate, while considering transmission-network power flow, distribution-network voltage constraints, line-capacity limits, energy-storage state of charge, charging/discharging restrictions, and reserve-margin requirements jointly determined by allowable deviations in PV output and load demand. Finally, to address the computational burden caused by the nesting of multi-objective planning and full-year coordinated transmission–distribution operational verification, a hierarchical solution framework tailored to the model structure is developed. The outer-layer MOEA/D searches for PV–ESS capacity configurations, the middle-layer surrogate model screens candidate solutions requiring exact evaluation, and the inner-layer ADMM coordinates PCC boundary variables between the transmission and distribution sides, thereby obtaining a Pareto solution set that satisfies cross-level operating constraints. The results of an 8760 h case study on a typical regional power system show that compared with the conventional hierarchical planning scheme, the proposed method reduces the PV curtailment rate from 8.7% to 4.6%, increases PV utilization hours from 1160 h to 1375 h, reduces the peak power imported at the PCC from 8.2 MW to 6.5 MW, and reduces the total annualized system cost by 9.3%, while satisfying network-security and voltage constraints. The proposed method can quantitatively evaluate the comprehensive performance of alternative PV–ESS configurations in terms of PCC power exchange, distribution-network voltage constraints, and annual operating cost, thereby providing a planning tool for the siting and sizing of distribution-side PV and storage in regional grids with clearly defined transmission–distribution boundaries.