Multilevel transmission line macromodeling and latency for the time domain simulation

This paper presents a multilevel transmission line companion macromodel based on the segmentation modeling for the time domain simulation. The techniques described in this work exploits the characteristic properties of the segmented transmission line model for a more efficient analysis. At each timepoint, multilevel transmission line macromodels will be internally computed and only its simplest macromodel will replace the transmission line in the network for performing the time domain analysis. This analysis yields the terminal voltages of the transmission line that are used as input voltage sources for another analysis that involves only the transmission line. This second analysis gives the values of the internal variables of the transmission Line and updates the values of its internal variables to be used at the next timepoint. Both of these analysis can be done efficiently by exploiting the identical properties of each subsegment of the transmission line model. Furthermore, if at any time tk the value of the input variables of a subsegment do not change its value from its previous timepoint, then its value at all the subsequent time steps will remain the same until a change in the input variables of the subsegment occurs. The latent subsegment variables can thus be used in the upper level without recomputation. Test results show that this multilevel macromodeling can speed up the computation about 10 times compared with direct calculation without macromodeling. After the latency technique is applied, a 50% speed improvement can be further achieved while yielding almost identical numerical results.