Transmission Network Expansion Planning Considering Security Constraints through Nodal Indexes

This paper presents a modelling approach for the Transmission Network Expansion Planning (TNEP) problem that considers security constraints through Weighted Transmission Loading Relief (WTLR) nodal indexes. Small scale generation was also included as a complement to candidate solutions to the TNEP. Additionally, this work describes a multi-objective approach for minimizing operating and investment costs while maximizing network security. The latter is modeled through WTLR nodal indexes that allow to measure the severity of overloads under normal operating conditions as well as under contingencies. Two different metaheuristics are implemented and compared: Non-dominated Sorting Genetic Algorithm II (NSGA-II) and Pareto Envelope-based Selection Algorithm II (PESA-II). Both techniques enable to find a set of solutions that represent a trade-off between the two objective functions (costs vs. security), over which the system planner is able to make decisions according to a given budget and security target. The results of the Garver's system and a benchmark IEEE power system support the applicability of the proposed model and the effectiveness of both metaheuristics.