Power-flow tracing and wheeling costing considering complex power and convection lines

In a competitive-market environment, deregulation of the electricity industry and thus transmission open access make it even more important to allocate the cost of transmission service fairly. The proposed method can deal with the problem of reactive-power decomposition which could not easily be resolved previously. An equivalent line circuit based on the nominal-T model for reactive-power decomposition is presented. Graph theory and the proportional-sharing principle are employed to trace power flow; the results are then employed to determine the real-power contribution of generators to lines and loads and the reactive-power contribution of generators and lines to loads. The proposed method is illustrated by means of a simple example. Because complex power rather than real power is considered, numerical results from the proposed method are more reasonable than those from the method which considers only real power.