Coupled PI Lines and Coupled PI Lines with Fault

As for the PI line model, the coupled PI line model is mainly used for short transmission lines.

Coupled PI Line Icon and Diagram

Parameter Description

The parameters for Coupled PI lines are the same as for those for simple PI lines, except that the dimension of the R, L and C matrices representing the impedances and admittances of the conductors is 6x6, instead of 3x3. The reason is that this model represents a line with six conductors. There is a new parameter for sequences. As for the simple PI model, the positive sequence and zero sequence parameters for each circuit are present. Moreover, the neutral coupling between
both circuits must be represented. This is referred to as mutual impedance and is represented only in zero sequence. The user must remember that if he uses the parameter input by sequences, the simulation will only be an approximation of the reality, the coupling between the phases of both circuits not being represented.

List of Available Signals

No line signal is available for coupled PI lines. The reason is that the calculations required to obtain
the signals would slow down considerably the time required to simulate the model. Hence,
only the fault signals are available.

Fault Signals

Coupled PI Lines and Coupled PI Lines with Fault Control Panels

Line Data

The geometric data of a coupled PI line are the exactly the same as those for a constant parameters
coupled line. Figures 7 - 15 to 7 - 16 show the geometric parameters required to calculate the electrical
parameters.