# Library

ARTEMiS/SSN/Lines

# Blocks

# Description

These blocks implement the Marti-type FD-line model, as described in [1].

These new blocks, known as SSN Marti-type FD-line model v2.0, implements an upgraded version of the previous FD-line code that don’t require X-type NIB at their terminals. The mode still requires the use of SSN solver however.

Marti-type FD-line model is an accurate line model ofr balanced and slightly unbalanced overhead lines. The Marti-type FD line model uses a modal transformation to compute the frequency dependent parameters as opposed to the SSN-WideBand model which directly models all its frequency dependent parameter in the phase domain. Cables in particular typically exhibit a strong frequency dependence of the modal transformation matrix, making the FD line model inaccurate in this case. The SSN-WideBand model is much more accurate with cables in this regard.

### RT-LAB task decoupling by mean of traveling wave delays

The new SSN Marti-type FD-line model v2.0 also presents itself as two half-line blocks that transmit their traveling wave data by Simulink signals. This new FD-line model can be used to decouple an electric systems, similarly of standard DPL models, but requires the users to manually route the two half-models in each SS_ subsystems of RT-LAB.

### Minimum delay requirements for multi-core decoupling

The new Wideband line model requires that the fastest mode of the line has a transport delay of at least 2*Ts, where Ts is the model sampling time.

Model symmetry: the two half-line models are identical and can be interchanged.

# Masks

# Parameters

**EMTP-RV Marti-type FD-line fitting file (.pun):** the name of the FD-line fitting data file, produced by EMTP-RV fitter or the eMEGAsim wideband fitter. This file has a .pun extension.

**Type of .pun file**: {Line or Cable}. EMTP-RV generates slightly different formats of .pun files for line and cables. Using Marti-type FD-line model for cables is not recommended however.

**Time step (s): **the model sample time in seconds.

# Input and Output signals

**Simulink connection points**

**Traveling wave signals**: the blocks have each one Simulink input and one Simulink output that must be connected to the complementary half-line, even across RT-LAB subsystems if RT-LAB model decoupling is desired.

**Physical Modeling connection points**

**Electric ports:** The line models also have PM type ports which corresponds to the electric phase connections in SPS.

# Examples

The model **ssn_Marti2_3ph** (R2015A+) is available on the installation path of ARTEMiS.

# References

[1] J.R. Marti, “Accurate Modeling of Frequency-Dependent Transmission Lines in Electromagnetic Transient Simulations”, IEEE Trans. On Power App. and Systems, Vol. PAS-101, No. 1, January 1982, pp. 147-155.

[2] C. Dufour, J. Mahseredjian , J. Bélanger, “A Combined State-Space Nodal Method for the Simulation of Power System Transients”, IEEE Transactions on Power Delivery, Vol. 26, no. 2, April 2011 (ISSN 0885-8977), pp. 928-935