LineCableLab

Toolbox in MATLAB for modelling of overhead and underground transmission lines.

LineCableLab (formerly OHLToolbox)

Toolbox in MATLAB for modelling of overhead and underground transmission lines (per-unit-length parameters, propagation characteristics, frequency scan, transient simulations).

Highlight of the main features

• LineCableLab is distributed with a GUI designed to aid data entry. You can save your projects in matfiles and recover them for later use.
• Several impedance and admittance formulas, frequency-dependent soil models and modal decomposition techniques are available.
• It is possible to work with overhead, underground and mixed overhead-underground conductor arrangements.
• Parameters are computed for any number of phases with any number of conductors per phase, with or without Kron elimination.
• You can export the computed data as a XML file compatible with ATPDraw 7.5, ATP-ULM (De Conti et al.) fitULM.dat file, also available in ATPDraw 7.5, or to a EMTP-compliant matfile to be used with the LineCable_Data routine available in the EMTP® software.
• Time-domain transient simulations using the Laplace transform, with several energization sources available.

Basic instructions

The use of the toolbox is quite self-explanatory. Launch the file 'linecablelab.mlapp' from MATLAB workspace and input the necessary information. You can save your design by clicking 'Save input session' or recover an existing design by clicking 'Load input session'.

You will be prompted to specify a JobID and this is mandatory. The JobID is a text string which will be used to identify all the output files and folders. When you are satisfied with the data entry, hit the button 'Start'. This will create a subfolder named JobID inside the working directory. Inside this folder you will find two files: 'LineData_fun.m' and 'RunJob_JobID.m'. Call the script 'RunJob_JobID.m' and that's it. Note that the GUI does not actually perform any calculations, it is only a wrapper to the main function call.

The columns under the header 'Line cross section & conductor data' are described as follows:

• 1 column -- PhaseNum: number of phase (set to 0 for Kron reduction, map to the same phase for bundled conductors).
• 2 column -- Horiz: y position of each conductor in meters.
• 3 column -- Vert: z position of each conductor in meters.
• 4 column -- IntRadius: internal radius of each conductor in meters.
• 5 column -- ExtRadius: external radius of each conductor in meters.
• 6 column -- CondResist: resistivity of the conductor in ohms-meter.
• 7 column -- CondPerm: relative permeability of the conductor in pu.
• 8 column -- InsulRadius: external radius of insulation in meters. Set to NaN if bare conductor.
• 9 column -- InsulPerm: relative permeability of insulation in pu. Set to NaN if bare conductor.
• 10 column -- InsulPermit: relative permittivity of insulation in pu. Set to NaN if bare conductor.

Acknowledgements

LineCableLab has been actively maintained and improved by Theofilos Papadopoulos, Andreas Chrysochos and Amauri Martins-Britto. The authors acknowledge and wish to thank for the efforts of all external contributors. Due to the dynamic and open nature of this project, it became unmanageable to keep an exhaustive list, so we decided to let GitHub handle it via issues reports, pull requests and/or commit history. You all are real badasses!

Important information

LineCableLab uses external tools that must be downloaded from the corresponding sources and placed in the appropriate directories, listed below:

• vfit3 - Fast Relaxed Vector Fitting, developed by Gustavsen et al. Available: https://www.sintef.no/globalassets/project/vectfit/vfit3.zip. Unzip the file into the folder 'JMartiModelFun/vfit3'. The vector fitting toolbox is used to create the ULM and JMarti line models from the modal parameters, if requested by the user.
• Eigenshuffle - Consistently sorted eigenvalue and eigenvector sequences, developed by John D'Errico. Available: https://www.mathworks.com/matlabcentral/fileexchange/22885-eigenshuffle. Unzip the file into the folder 'mode_decomp_funs'. The Eigenshuffle code is used as an additional method to perform the modal decomposition avoiding switchovers in the frequency-domain.
• Bodefit - Bode process program, developed by E. S. Bañuelos-Cabral et al. Available: https://www.intechopen.com/chapters/57667. Deploy the file 'Bode_process.m' to the folder 'JMartiModelFun/functions'. In case the VF does not converge to a stable solution (real poles only), the Bodefit is used as alternative, at the cost of accuracy.
• Carson's integral - Closed-form solution proposed by T. P. Theodoulidis. Available: https://www.mathworks.com/matlabcentral/fileexchange/50134-carson-s-integral. The files are packaged in the toolbox and no further action is required.

These codes are properties of the respective authors, with all due credits given. Observe any restrictions and licensing/usage requirements in the corresponding websites.

On the computational methods implemented in LineCableLab

The toolbox incorporates several impedance and admittance formulas, under different assumptions to represent the imperfect earth in the line models. For a comprehensive analysis, please refer to the following scientific publications:

• Transient Electromagnetic Interference between Overhead and Underground Conductors
• Closed-form expressions for the analysis of wave propagation in overhead distribution lines
• A generalized model for the calculation of the impedances and admittances of overhead power lines above stratified earth

Restrictions of use

We appreciate the interest in our work and we invite the interested users to use our codes as necessary, as long as they are not embedded in any commercial software, which is strictly prohibited. However, if you use LineCableLab as a part of scientific research, we kindly ask you to refer to our published papers:

• A. G. Martins-Britto, T. A. Papadopoulos and A. I. Chrysochos, "Transient Electromagnetic Interference between Overhead and Underground Conductors," in IEEE Transactions on Electromagnetic Compatibility, Mar. 2024, doi: 10.1109/TEMC.2024.3376971.

• T. A. Papadopoulos, Z. G. Datsios, A. I. Chrysochos, A. G. Martins-Britto, G. K. Papagiannis, "Transient induced voltages on aboveground pipelines parallel to overhead transmission lines," in Electric Power Systems Research, 109631, ISSN 0378-7796, Jun 2023, doi: 10.1016/j.epsr.2023.109631.

• T. A. Papadopoulos, A. I. Chrysochos, C. K. Traianos, and G. Papagiannis, “Closed-Form Expressions for the Analysis of Wave Propagation in Overhead Distribution Lines,” in Energies, vol. 13, no. 17, p. 4519, Sep. 2020, doi: 10.3390/en13174519.

• A. I. Chrysochos, T. A. Papadopoulos and G. K. Papagiannis, "Robust Calculation of Frequency-Dependent Transmission-Line Transformation Matrices Using the Levenberg–Marquardt Method," in IEEE Transactions on Power Delivery, vol. 29, no. 4, pp. 1621-1629, Aug. 2014, doi: 10.1109/TPWRD.2013.2284504.

• A. G. Martins-Britto, T. A. Papadopoulos, Z. G. Datsios, A. I. Chrysochos and G. K. Papagiannis, "Influence of Lossy Ground on High-Frequency Induced Voltages on Aboveground Pipelines by Nearby Overhead Transmission Lines," in IEEE Transactions on Electromagnetic Compatibility, vol. 64, no. 6, pp. 2273-2282, Dec. 2022, doi: 10.1109/TEMC.2022.3201874.