On-line calculation of incremental transmission losses in an electric power system

Two methodologies to calculate the incremental transmission losses directly from the system configuration and variables, voltage phase angle and magnitude, are presented. The system configuration and system variables are assumed to be available from a state estimator. For any changes or disturbances to the system, such as a dramatic load shift, transmission line outage, and/or different interchange level, the state estimator would reflect these changes on the system configuration and system variables. These methodologies provide real-time or online incremental transmission losses that would be needed for an economic dispatch of a system. The methodologies of online calculation of incremental transmission losses presented show a viable and favorable alternative to the methodology used by the B-coefficients. Simulation results are presented