SELECTION OF OBJECTIVES IN MINIMUM LOSS POWER FLOW IN HYDROTHERMAL ELECTRIC-POWER SYSTEMS

Two formulations of the optimal minimum loss hydrothermal power flow problem in electric power systems are discussed. The formulations - one based on Kron's loss objective function and the other a network-based loss formulation - are treated in detail and the results of the two approaches are compared using two standard test systems. For the systems investigated, Kron's loss minimization schedules higher thermal generation than that required by the network loss minimization during lower demand. Kron's loss minimization involves lower active power transmission losses than those involved by the network-based loss minimization during low demand, and higher active power transmission losses than those required by the network-based loss minimization during higher demand. The total energy loss involved in the outcome of the Kron's loss minimization results is higher than that due to the network-based loss minimization schedule. There is a negligible difference in voltage magnitudes. Reactive power generation results favour the network-based loss approach. On the basis of the experiments, it is concluded that a network-based loss model is preferable in this application. © 1990.