Reliability-Constrained Transmission Expansion Planning Integrating Probabilistic Reliability Indices and N–1 Security Criteria

Transmission expansion planning must ensure an infrastructure capable of meeting growing demand while simultaneously taking into account economic, operational, and reliability criteria. This paper proposes a multi-period methodology for transmission expansion planning formulated as a mixed-integer linear programming (MILP) problem based on DC-OPF, which incorporates single transmission-corridor contingencies under the N–1 criterion and the cost of Expected Energy Not Supplied (EENS) in the objective function. The methodology jointly determines the circuits to be built, their commissioning phase, and system operation for the different states considered. The model’s performance is evaluated on the 6-bus Garver system and IEEE RTS-24 systems for a horizon comprising years 0, 5, and 10, and is compared with a traditional TEP approach. The results show that incorporating reliability modifies the location and timing of investments, as well as generation dispatch and the distribution of power flows. In year 10, the cost obtained using the proposed methodology exceeds that of the traditional TEP by approximately 50.5% for Garver and 10.7% for IEEE RTS-24. In the latter system, the selected reinforcements allow for zero values of EENS, LOLP, and LOLE to be achieved in years 5 and 10 for the evaluated contingencies. The results demonstrate that the proposed methodology explicitly quantifies the trade-off among investment cost, operating cost, and the expected consequences of load curtailment, and that this trade-off depends significantly on network topology and initial redundancy.