Description

The ARTEMiS-SSN WideBand Line block implements an N-phase distributed parameters transmission line model with frequency dependence of line parameters using full-phase domain modelisation.

The ARTEMiS-SSN WideBand Line block implements an N-phases distributed parameters line model with frequency dependence of line parameters.

In difference to the ARTEMiS-SSN FD line model which uses a modal transformation to compute the frequency dependant parameters, the WideBand model directly models all its frequency dependant parameter in the phase domain, avoiding the error caused by the use of a constant modal transformation matrix in FD line model.

Cables in particular typically exhibit a strong frequency dependant of the modal transformation matrix, making the FD line model inaccurate in this case.

The WideBand model is much more accurate with cables in this regard [1]. This model is optimized for discrete real-time simulation and allows the decoupling of network connected on each side of it. It also allows multi-CPU simulation on an RT-LAB simulator.

Table of Contents

Mask and Parameters

>>wbfit =
Number of phases	the number of phases of the model (1-2-3-4-6-8-10-12)
Line data variable	the name of a MATLAB workspace variable containing the WB line parameter. The variable is a structure containing the various parameter of the model.
Nph	number of phases
Ng	Number of propagation groups
tau	Propagation delays
NYc	Yc fitting order
YcNpR	Number of real Yc poles
YcNpC	Number of complex Yc poles
YcR	Real Yc poles
YcCR	Real part of complex Yc poles
YcCI	Imaginary part of complex Yc poles
YcstD	Yc constant residues
YcRres	Residues of real Yc poles
YcCRres	Real Part of Residues of complex Yc poles
YcCIres	Imaginary part of Residues of complex Yc poles
NH	H fitting order
HNpR	Number of real H poles
HNpC	Number of complex H poles
HR	Real H poles
HCR	Real part of complex H poles
HCI	Imaginary part of complex H poles
HRres	Residues of real H poles
HCRres	Real part of Residues of complex H poles
HCIres	Imaginary part of Residues of complex H poles
The document untitled *'Obtaining WideBand line model parameters from EMTP-RV'* explains how to get these parameters from the fitting routines of EMTP-RV. It can be found in the installation repository of ARTEMiS: *pathtorepository/ARTEMiS/artemis_version*/art_r201XY/auxiliary_routines/wideband/line_param/Obtaining_WideBand_ine_model_parameters_from_EMTP_RV.pdf
Unique Tag Identifier	a user set string that must be unique for each instance of this block inside a Simulink model. (Note: in future releases, this parameters will be set automatically and will not be visible from the user)
Voltage measurement and Current Measurement choice	User decides if they want to measure others parameters of the line like phase voltage or phase current. (Note: the voltage is a phase-to-ground measurement)
Voltage and Current Label	User can specify a label for its current or voltage values. In case the previous choices have been setted up to yes, current and voltage labels provided by the user are used to retrieve current. This can be performed using ‘label_’s for the sending side of the line ( the one connected to the source) and ‘label_r’ for the receiving side of the line.

Inputs and Outputs

Inputs

N-Phase voltage-current signals

Outputs

N-Phase delayed voltage-current signals.

Example

3-phase Cable Energization

In the demo, a 15 km 3-ph cable (equivalent to 6 phase line considering the sheath) is energized with an open end. The sheath is grounded with 10 Ohms resistors at both ends. See the ‘Demo Validation against EMTP-RV’ section at the end of this document for more info on this test case.

The WD-line model was fitted with a total of 14 poles for the characteristic admittance Yc(w) and 36 for the 6 propagation functions H1(w) to H6(w).

To make this interface, the FD-line model must be used in conjunction with SSN Nodal Interface Blocks (NIB) with the X-type interface chosen in the direction of the FD-line. The NIB can connect to other SSN groups of either V- I- or X-type.

Energization from a balanced source results in receiving end cable core voltage in the figure below.

Going to real-time

The distributed configuration of RT-LAB allows for complex models to be distributed over a cluster of PCs running in parallel.

ARTEMiS WideBand lines (and also FD-line, Distributed Parameters Lines and Stublines) can be used to make the parallel simulation of an electric circuit. ARTEMiS used the intrinsic delay of the line to split the circuit without affecting the dynamic property of the system. See the ARTEMiS Distributed Parameter Line documentation for a complete example of the usage of ARTEMiS line models in the RT-LAB framework.

For real-time simulation the model had to be prepare according to RT-LAB conventions (SM_ SS_ prefix for top-level Simulink groups for example). This demo model is already like this, the user can optionally add a RT-LAB console with an SC prefix.

Compilation of this model in RT-LAB will results in two independent tasks (sm_master and ss_slave) interconnected by the WideBand-line which will transmit their propagation voltage and currents between the two subsystems.

Characteristics and Limitations

Usage of the WideBand line model in RT-LAB as task decoupling elements

When used in RT-LAB to decouple and separate computational tasks on different cores/CPUs, the following connection restrictions are applicable to the ARTEMiS distributed parameters line model:

The ARTEMiS-SSN WideBand Line must be located on the top-level of the RT-LAB compatible Simulink model

Each ARTEMiS-SSN WideBand Line outport can be connected only to Simscape Electrical Specialized Power Systems (SPS) component located inside RT-LAB top-level subsystem (names beginning with ’SS’ or ’SM’ prefixes)
No connection between ARTEMiS-SSN WideBand Lines is allowed on the top-level. If such a connection is required, the ARTEMiS-SSN WideBand Line block connection lines must be first routed inside the subsystems individually and the connection between the ARTEMiS-SSN WideBand Line ports can be made inside the subsystem.

SSN solver in the ARTEMiS GUIde block

The SSN solver of the ARTEMiS GUIde block should be ’Trapezoidal’ when using an ARTEMiS-SSN WideBand Line block. This is because the Trapezoidal solver is used internally by the ARTEMiS-SSN WideBand Line block.

Initialisation

The ARTEMiS-SSN WideBand Line block does not initialize in steady-state so unexpected transients at the beginning of the simulation may occur.

Direct Feedthrough	No
Discrete Sample Time	Yes, defined in the ARTEMiS guide block
XHP Support	Yes
Work Offline	Yes

Related Items

Since ARTEMiS 7.3.5, new Wideband line models will be available in the SSN section of ARTEMiS. These new models overcome some rare numerical issues and are easier to use because they don’t need X-type NIBs to be connected to the SSN model.