Integrated SVC and step-down transformer model for Newton-Raphson load flow studies

This letter presents an integrated static VAr compensator (SVC) and step-down transformer model suitable for power flow studies using the Newton-Raphson method. The SVC is taken to be a continuous, variable-shunt susceptance that is adjusted automatically to satisfy a specified voltage magnitude. The step-down transformer is represented by an admittance that combines easily with the variable susceptance, representing the SVC plant. The resulting equivalent model allows for a direct SVC voltage regulation at the high-voltage side of the transformer, which does not compromise the quadratic convergence characteristics of the Newton-Raphson method.