I built two simulation models based on the transmission line model with the same parameters, one works and one doesn’t, can you help me see why? Also, regarding the ground of the transmission line, is it possible to consider it as a fourth wire? After all, it has its own impedance and inductance as the length increases.
sy.plecs (18.5 KB)
sy1.plecs (13.1 KB)
I built two simulation models based on the transmission line model with the same parameters, one works and one doesn’t, can you help me see why?
The model that is unstable is a distributed-parameter / traveling wave transmission model which is distinct from the PI-section model. I’ll also note that the PI section model implementation in your model differs from that of the PLECS Library model - namely how the capacitance is distributed. It seems that with the parameters you specified the traveling wave model is inherently unstable.
Also, regarding the ground of the transmission line, is it possible to consider it as a fourth wire?
It is it’s own unique electrical terminal, but it isn’t a “wire” in that it has an impedance that is a function of length, but rather the impedance between the phase wires and neutral changes with length.