An approach for transmission system expansion planning in electricity market

In a competitive environment the rule of the Independent System Operator (ISO) is to provide a non discriminatory access and services to all the market participants, maintaining a good level of reliability. At the same time, the planners have a lot of constraints and uncertainties associated to competitive environment. In this context transmission system expansion planning (TSEP) becomes more complex and needs new probabilistic tools and market-based criteria. So many new multi-objective (MO) models are proposed in literature usually including as objectives social welfare or competitiveness maximization and transmission congestions minimization. In the present work the proposal is to integrate to the standard formulation of TSEP a new parameter that is the flexibility, defined as the ability to adapt the planned development of the transmission system, quickly and at a reasonable cost, to any change in the conditions considered at the planning time. From this general definition, a more specific meaning of flexibility has been extracted, that is the one of transmission system in respect of the generation changes. This definition allows to consider it as a good attribute for the optimal transmission planning evaluation, to add to the main objectives of TSEP.