I understand you are looking to model underground transmission lines in MATLAB/Simulink. This can be done using blocks available in Simscape Electrical.
Few of the blocks that can be used are:
1. PI Section Line – models a short cable segment with lumped R, L, and C parameters.
2. Distributed Parameters Line (Frequency-Dependent) – Implements an N-phase distributed parameter line model with lumped losses and provides a more accurate representation for long underground cables.
3. AC Cable (Three-Phase) Block – specifically designed for power cables, including sheath modeling and bonding configurations.
For detailed MATLAB examples, refer to the below documentation links:
- AC Cable with Bonded Sheaths: https://www.mathworks.com/help/sps/ug/ac-cable-with-bonded-sheaths.html
- Four Coupled 66-kV Cables: https://www.mathworks.com/help/sps/ug/computation-of-r-l-and-c-cable-parameters.html
I hope this is helpful!
