The part of the network diagram, about which only general parameters are known, is modeled using an equivalent power system. In the phase coordinate method, the equivalent power system is modeled by the resistances in the direct and zero sequence and by the voltage source.
Phase coordinates method
The phase coordinate method for modeling electrical networks with a grounded and isolated neutral, calculation of short circuit currents.
Calculation of transfer matrices of multipoles of various shapes is quite simple. Transfer matrices are a mathematical description of the circuit under consideration, which defines the relationship between the input quantities and the output values of the multipole.