Transmission Network Expansion Planning Based on Chronological Evaluation Considering Wind Power Uncertainties

Transmission network expansion planning (TNEP) is expected to cope with the power transmission inadequacy problem resulting from rapid growth of wind generation in power systems. However, due to significant uncertainties on the generation side, TNEP based solely on one snapshot or a limited number of scenarios cannot capture the time-variant characteristics of wind power and may be suboptimal. In this paper, a new heuristic methodology for TNEP based on chronological evaluation is presented. First, to assess the transmission adequacy, the multiperiod DC optimal power flow considering the generators' ramping limits is employed for a system production simulation covering an entire year. Second, two sensitivity factors derived from Lagrange multipliers, i.e., the sensitivity factors of the branch capacity and the branch admittance, are applied to determine the initial set of the transmission network expansion plan (I-STNEP). Finally, the cost-benefit incremental relationship index and a degressive method are used to identify the best subset of the transmission network expansion plan within the I-STNEP. Simulation results based on a 3000-bus real-world network in northern China validate the effectiveness of the proposed TNEP method.