Universal distribution factors for power system open-market studies

AC distribution factors have been used extensively in the recent power and energy pricing studies in free electricity market environment. Because the AC power flow in a given transmission line depends on the complex voltage value at the point of calculation along the line, distribution factors relating line flows to bus injected powers would also depend on such point of calculation. In open-market pricing studies, more flexibility is needed in the derivation and use of power distribution factors in order to allow market entities to base their calculated line flows on a reference (point of calculation) of their market contractual choice. This paper presents a novel model for evaluating universal distribution factors, which are suitable for a wide range of power system analysis and electricity market pricing studies. These universal distribution factors are compact matrix-form expressions with total flexibility in defining the position on the line at which line flows are measured. They are independent of bus power injections and, therefore, can be used for analyzing different pricing scenarios involving different bus power contributions. The paper also demonstrates the practical calculation of the universal distribution factors as well as their sensitivities with respect to the line voltage profile.