Mercados de energia elétrica: uma proposta para a alocação dos custos de perdas em sistemas de transmissão

Abstract

This work presents a new methodology for allocating transmission losses to the participants of an electric energy market. The proposed approach is based on the incremental transmission loss concept and is implemented through two models: Basic and Extended. In the Basic Model, the total system losses are estimated through the linear DC load flow equations, while the Extended Model uses the exact AC formulation. The concept of Center of Losses is used; a fictitious bus in the system network where all transactions are compensated for transmission losses. Both models provide a sharing of transmission losses among generators and loads based on a pre-defined proportion, for instance, 50:50% for each participant class. Concerning the operation of interconnected systems, it is recognized that the physical limitations of transfers between areas/subsystems contribute to the appearing of sub-markets, characterized by offering different prices to their customers. In this new context, it becomes strategic to evaluate the influence of power interchanges on the total system losses, bearing in mind that the price schemes of the involved areas should not be affected. Thus, the proposed formulation is generalized in order to identify through a decomposition technique, the amount of losses that each participant in the market causes on all system areas. The concept of interchange losses is introduced: the total amount of losses that occurs outside a given market whose agents are responsible for causing them. Some criteria to share these losses among the market agents are presented and discussed. Several important aspects related with the allocation fairness and transparency are illustrated by numerical applications with the IEEE Reliability Test System and other test systems. The corresponding results are deeply discussed.