The distribution substation planning is faced with numerous uncertainties so that the planning result can only be a “rough outline

” and the problem of determining the planning period arises. On the basis of the assessment of uncertainties in distribution planning

a specific approach to determine the planning period of a distribution substation based on acceptable errors is proposed

indicating that the load forecast error is the key factor to affect the planning period. In order to provide a clearer understanding of this paper's primary objective

the proposed approach is applied to determining the planning period of a power supply radius optimization (PSRO) model in distribution substation planning. Finally

an example is illustrated which validates the suggested approach of this paper.