Frequency Dependent Transmission Line Modeling Utilizing Transposed Conditions

Existing phase domain transmission line models are capable of producing highly accurate results for both overhead lines and underground cables. This paper introduces a hybrid line model that gives substantial savings in computation time without loss of accuracy, when one or more circuits of a transmission system are treated as continuously transposed. This is achieved by means of a constant transformation matrix in combination with a reduced-size phase domain line model and a number of single phase (modal) line models. The calculated examples demonstrate a potential speed increase over a full phase domain model between 3 and 4. If none of the circuits are transposed, the line model degenerates into a full phase domain line model.