Implementation of a VFT model in PSS/E suitable for power flow and transient stability simulations

This paper presents the implementation of a variable frequency transformer, suitable for planning studies of asynchronous links, using the Power System Simulator for Engineering software. The variable frequency transformer model for power flow solutions is represented as a phase-shifting transformer, where the phase shift angle is adjusted to maintain the active power exchange within power limits. The backbone of the variable frequency transformer representation for transient stability simulations relies on the equations of motion of its rotary machine, which represent the dynamic behavior during the time domain simulation. Besides, a drive control system with power and speed regulators is incorporated in order to provide a smooth dynamic operation during disturbances. An asynchronous interconnection test case comprising three 100 MW VFTs is presented in this work to study a prospective project to link the power network of Baja California with the Interconnected National System of México.