Open

Description

The constant parameter (CP) line model assumes that the line parameters R, L, and C are independent of the frequency effects caused by the skin effect on phase conductors and on the ground. The model considers L and C to be distributed (ideal line) and R to be lumped at three places (R/4 on both ends and R/2 in the middle). The shunt conductance G is taken as zero. The frequency dependence of the line parameters (represented in the FD model) is an important factor for the accurate simulation of waveform and peak values. However, the CP model is very robust, simple, and fast. It also provides a good alternative for a first approximation analysis.

A transposed or untransposed CP line is represented by a) its sequences, or b) its propagation modes and the transformation matrix (Ti) between mode currents and phase currents. Implementation details can be found in [1].

The 6-phase CP model is used to simulate a double-circuit line or two lines with the same right of way. The parameters for 6-phase lines are the same as for 3-phase lines. The only difference is that the modal transformation matrix of double transmission lines is a 6x6 matrix because each bundle of conductors is considered as a separate phase.