Optimization of DC Terminal Location for UHVDC Hierarchical Connection to Power Grid

Large grid interconnection is an important form of Energy Internet. Ultra-high voltage direct current (UHVDC) plays an increasingly important role in the interconnection of large power grids, which helps to optimize the allocation of resources in a wide area. UHVDC hierarchical connection mode, in which the UHVDC inverter station connects to different voltage level AC system, provides an effective means to evacuate the high-capacity power of UHVDC access to the load center. DC terminal location selection is a multi-objective decision problem. Considering the characteristics and influence of UHVDC hierarchical connection to power grid, the comprehensive evaluation indexes are established in this paper, on the basis of which DC terminal location selection strategy by the use of Technique for Order Preference by Similarity to Ideal Solution (TOPSIS) method. Finally, an actual project of UHVDC hierarchical connection to system is taken for an example and four different UHVDC hierarchical connection schemes are discussed in this paper. The result shows that effective decision support for UHVDC hierarchical terminal location planning can be provided with the proposed method.