Variable Series Impedance Model of a Unified Power Flow Controller for Load Flow Analysis

Abstract

This article proposes a novel model of a unified power flow controller for load flow analysis. This model is based upon an innovative approach, where the real power exchange of series and shunt elements of a unified power flow controller are decoupled with each other, and the susceptance of the series transformer is considered as a new state variable. The unified power flow controller model is incorporated into an existing Newton–Raphson load flow algorithm, and a Jacobian matrix is modified to incorporate the decoupled modes of the power exchange of series and shunt elements of the unified power flow controller as new state variables. The proposed model considers constraints of thermal power limits of a unified power flow controller. The modeling approach presented in this article is tested on standard IEEE 30-bus and IEEE 118-bus systems to validate its feasibility.

Keywords:

• unified power flow controller
• flexible AC transmission system
• load flow analysis
• power injection model