Transmission Loss Allocation Based on Circuit Theories and Orthogonal Projection

This paper presents a loss allocation method based on the circuit theories and the concept of orthogonal projection for pool-based electricity markets. The method first defines the current projection component to determine the share of a generator or load on the current through a branch. Then the power flow through each branch is decomposed and the branch loss allocation is obtained. One feature of the method is that it gives intuitively clear explanation of the obtained loss allocation. The two equivalence modes of bus power injections are also discussed. The analysis shows that the equivalence that loads (generators) are converted into equivalent admittances when generators (loads) are converted into current injections reflects the practical situation and thus it is more reasonable and preferable. Comparisons with other methods and validation tests of the proposed method are provided by using several numerical examples.