Hi,

Does anyone has an idea how to combine a series a pi-section-elememts of a transmission line (R, XL, C) to a single pi-model? Using only R and X would be easy, but how can I handle the capacitance?

Nice regards

Finally I've found the solution:
1. You need to construct for example two Y-matrices of the 2 PI-equivalent circuits
2. Then use the interrelations (e.g. from wikipedia) of two-port-networks to transform each Y-matrizes into the ABCD- or chain-matrix (there exists a lot of notations), lets name them A1 and A2
3. Summarize the matrices: A=A1+A2, which equals a series connection
4. Then convert A back to a single Y-Matrix
5. Size comparison allows to find the single values of each element of the PI-equivalent R, XL, C and G (a comparison with the rules of constructing the Y-matrix may be helpful)

Nice regards