An investigation on the accuracy of DC methods for losses allocation in electricity power markets

摘要

This paper investigates a DC method for losses allocation to be implemented at the Brazilian electricity market. It is based on incremental methodologies and defines losses factors for generators and loads. This technique uses a DC load flow to calculate the total system losses and the losses factors. It does not consider the complete power flow equations. Because of this, this method may provide unfair losses allocation depending on the system operation condition. Hence, it is developed a new methodology to calculate the losses factors, based on incremental methods but using an AC load flow that takes into account the system non-linearity. These two methodologies are applied to a small system and to a version of the Brazilian Northwest system and the results are compared. The losses solved by a DC power flow differ immensely from the AC losses for heavy loading conditions, where the impact of the power flow non-linearity grows up. In conclusion, this paper demonstrates that DC methods may be inadequate for transmission systems losses allocation. Mainly for heavy loading situations it is necessary to use methods based on complete AC power flow models.