Transformer with fixed voltage ratio k = rFixed*exp(j*thetaFixed). The series impedance R+jX and shunt admittance G+jB are referred to the high-voltage side B.
Step-up transformers with fixed voltage ratio can be implemented by only setting rFixed and leaving thetaFixed to zero default value. Phase shifters can be implemented by only setting thetaFixed and leaving rFixed to the default of 1.
Implemented as a child class of PiNetwork, where Ya=0, Yb=G+jB and k = rFixed*exp(j*thetaFixed), see the corresponding documentation.