Abstract:
As the number of HVDC projects grows, the issue of fault transfer between the sending and receiving ends of DC has arisen, significantly impacting the safe and stable operation of the grid. However, the traditional DC planning has not considered the fault transfer between sending and receiving ends. Therefore, this paper proposes optimization indices and methods for DC terminal location considering the fault transfer between the sending and receiving ends. First, the fault transfer process under AC-DC superposition interaction is analyzed, the AC-DC superposition interaction factor (ADSIF) and AC-DC short-circuit ratio (ADSCR) are proposed to reflect the AC-DC superposition interaction, and the influence of planned DC on the integrity and interference of the sending- and receiving-side grid is reflected from the perspective of AC nodes. Next, the sending- and receiving-side near-zone stability factor (SRNSF) reflecting the energy stability of the DC terminal location near-zone is proposed, and the multi-DC power impulse energy reflecting the fault transfer degree between sending and receiving ends is presented, as well as the fuzzy index commutation failure pulse frequency (CFPF). Then, an optimization method based on Vague set satisfaction boundaries improvement is proposed to realize accurate processing of optimization indices. Finally, simulation analysis is carried out based on the Northwest-East China interconnected multi-DC power grid, which verifies that the indices and methods proposed in this paper can effectively alleviate the fault transfer between sending and receiving ends in the planning level.