power_cableparam

Compute RLC parameters of radial copper cables with single screen, based on conductor and insulator characteristics

Syntax

power_cableparam
[r,l,c,z] = power_cableparam(CableData)


Description

power_cableparam opens the Cable Parameters Tool with the default cable parameter values provided by Simscape™ Electrical™ Specialized Power Systems software.

[r,l,c,z] = power_cableparam(CableData) computes the impedances and capacitances of a structure, CableData, that represents a set of cables that have a screen conductor.

Input Arguments

CableData — Conductor and insulator characteristics

structure

Conductor and insulator characteristics for a set of cables that have a screen conductor, specified as a structure with the following fields:

Field	Description
N	the number of cables
f	the frequency in hertz to be used to evaluate RLC parameters
rh0_e	the ground resistivity (in ohm.meters)
n_ba	the number of strands contained in one phase conductor
d_ba	diameter of one strand (in m)
rho_ba	DC resistivity of conductor in ohms*m.
mu_r_ba	relative permeability of the conductor material.
D_a	phase conductor outside diameter (in m)
rho_x	DC resistivity of the screen conductor in ohms*m.
S_x	Total section of screen conductor (in m^2)
d_x	screen conductor internal diameter (in m)
D_x	screen conductor external diameter (in m)
GMD_phi	Geometric Mean Distance between the cables.
d_iax	phase-screen insulator internal diameter (in m)
D_iax	phase-screen insulator external diameter (in m)
epsilon_iax	relative permittivity of the phase-screen insulator material.
d_ixe	outer screen insulator internal diameter (in m)
D_ixe	outer screen insulator external diameter (in m)
epsilon_ixe	relative permittivity of the outer screen insulator material.

Output Arguments

[r l c z] — Parameters of radial copper cables

structure

Parameters of the radial copper cables, returned as a structure with the following fields:

Variable, Field	Description
r.aa	Self resistance of phase conductor, in Ohm/Km
r.xx	Self resistance of screen conductor, in Ohm/Km
r.ab	Mutual resistance between the phase conductors, in Ohm/Km
r.ax	Mutual resistance between phase and screen conductors, in Ohm/Km
l.aa	Self inductance of phase conductor, in Henries/Km
l.xx	Self inductance of screen conductor, in Henries/Km
l.ab	Mutual inductance between the phase conductors, in Henries/Km
l.ax	Mutual inductance between phase and screen conductor, in Henries/Km
c.ax	Capacitance between the phase conductor and its screen conductor, in Farad/Km
c.xe	Capacitance between the screen conductor and the ground, in Farad/Km
z.aa	Self impedance of phase conductor, in Ohm/Km
z.xx	Self impedance of screen conductor, in Ohm/Km
z.ab	Mutual impedance between phase conductors, in Ohm/Km
z.ax	Mutual impedance between phase and corresponding screen conductors, in Ohm/Km

Building the RLC Matrices

These computed resistances, impedances, and capacitances need to be organized into 2N-by-2N matrices that can be directly used in the block you selected to model your cable. See the 4 Cables with screen (PI model) block in the power_cable example.

The RLC matrices are defined as follows (the example is given for a 3-cable configuration):

$$\begin{array}{cc}R=\left[\begin{array}{cccccc}{r}_{aa}& r_{ax}& r_{ab}& r_{ab}& r_{ab}& r_{ab}\\ r_{ax}& r_{xx}& r_{ab}& r_{ab}& r_{ab}& r_{ab}\\ r_{ab}& r_{ab}& r_{aa}& r_{ax}& r_{ab}& r_{ab}\\ r_{ab}& r_{ab}& r_{ax}& r_{xx}& r_{ab}& r_{ab}\\ r_{ab}& r_{ab}& r_{ab}& r_{ab}& r_{aa}& r_{ax}\\ r_{ab}& r_{ab}& r_{ab}& r_{ab}& r_{ax}& r_{xx}\end{array}\right]& L=\left[\begin{array}{cccccc}{l}_{aa}& l_{ax}& l_{ab}& l_{ab}& l_{ab}& l_{ab}\\ l_{ax}& l_{xx}& l_{ab}& l_{ab}& l_{ab}& l_{ab}\\ l_{ab}& l_{ab}& l_{aa}& l_{ax}& l_{ab}& l_{ab}\\ l_{ab}& l_{ab}& l_{ax}& l_{xx}& l_{ab}& l_{ab}\\ l_{ab}& l_{ab}& l_{ab}& l_{ab}& l_{aa}& l_{ax}\\ l_{ab}& l_{ab}& l_{ab}& l_{ab}& l_{ax}& l_{xx}\end{array}\right]\end{array}$$

$$C=\left[\begin{array}{cccccc}{c}_{ax}& -c_{ax}& 0& 0& 0& 0\\ -c_{ax}& c_{ax}+c_{xe}& 0& 0& 0& 0\\ 0& 0& c_{ax}& -c_{ax}& 0& 0\\ 0& 0& -c_{ax}& c_{ax}+c_{xe}& 0& 0\\ 0& 0& 0& 0& c_{ax}& -c_{ax}\\ 0& 0& 0& 0& -c_{ax}& c_{ax}+c_{xe}\end{array}\right]$$

Examples

For an example using the power_cableparam function, see the power_cable model.