Hello Sergey,
for specialized power systesm, we recommend that you use solver ode23tb. You mention that you get the same results regardless of solver. This transient looks like ringing that could genuinely be there because of the inductances and capacitances in your model. You would need to provide a full schematic of the EMTP and simulink model to make a comparison before determining if anything is wrong. It is most likely that this circuit is not actually set up the same as the EMTP circuit and that both tools are simulating correctly for the data that was entered into them. Transferring a circuit from one simulator to another can often lead to unforseen differences because not all parameters are specified the same and similar blocks may behave differently than you expect. The most likely block to be causing problems would be the PI transmission line. After that, i would check the load block.
Regards,
Joel
