Abstract: For the complex and insufficiently adaptable grid structure of the ultra-high voltage access transmission network and even the waste of resources caused by the independence of grid planning and open-loop partition decision-making, this paper introduces singular value decomposition (SVD) and feature indexing techniques. It proposes a multi-stage planning method for the transmission network, considering the open-loop partition of electromagnetic loop networks and typical 500/220 kV power supply structures. Firstly, the path features of typical power supply structures are extracted, accompanied by the proposal of a typical power supply structure index strategy based on label path features. Then, a similarity index of typical power supply structures based on SVD is constructed. Based on this, a planning model for similarity recognition is established to maximize the similarity of typical power supply structures. Finally, a feedback regulation mechanism and solution method are proposed to coordinate the decision-making information between grid planning and open-loop partition in each stage. Compared to traditional planning methods, the proposed method mitigates the waste of resources resulting from open-loop partition decisions at different stages and reduces the calculation of complex planning indices. As a result, it establishes a grid structure characterized by heightened power supply reliability, operational flexibility, and robust adaptability. The effectiveness and accuracy of the proposed method are validated through a practical case study of a power grid in Hunan Province.