This paper presents a methodology for the optimal location of distributed generation (DG) in power systems using the Weighted Transmission Loading Relief (WTLR) nodal indexes. These indexes are used to guide a GRASP metaheuristic in charge of the optimal allocation of different DG units in a transmission network. The objective consists on minimizing the most negative WTLR indexes, which results in an increase of the system security. Several tests are presented in a representative prototype of the Colombian power system, evidencing the effectiveness of the proposed methodology. Results show that a proper allocation of DG units minimizes system overloads both in normal operation and under contingencies.

This paper presents an assessment methodology of transmission expansion plans based on the weighted transmission loading relief (WTLR) nodal indexes. These indexes allow to measure the security of a power system in normal state and under contingencies. Though the WTLR indexes it is possible to identify critical elements of the network and buses where it is recommendable to have more generation. Four expansion proposals for the Colombian power system, reported in the technical literature are compared. The strengths and weaknesses of expansion plans are identified based on their corresponding WTLR indexes.