Mathematical Model and Steady-State Operational Characteristics of a Unified Power Flow Controller

The paper presents a mathematical model and steady-state operational characteristics of a Unified Power Flow Controller (UPFC). The mathematical description is based on the transformation of a three-phase system into an orthogonal synchronously rotating coordinate system, in which, under steady-state conditions, all the system quantities are constant values. Thus, at given parameters, it is generally possible to determine the dimensions of the device. The analysis of the steady-state operational characteristics resulted in key findings enabling derivation of control algorithms and further examination of the device operating under dynamic conditions.