MATLAB Implementation of UPFC Control for 5-Bus Power System

This article presents a comprehensive MATLAB implementation of Unified Power Flow Controller (UPFC) coding for a 5-bus power system. The UPFC represents a crucial power electronics device designed for simultaneous control of voltage magnitudes and active/reactive power flow in electrical networks. Our implementation focuses on developing modular MATLAB functions that model the UPFC's series and shunt converters, including proper initialization of system parameters using structured data arrays. The coding methodology incorporates Newton-Raphson power flow algorithms enhanced with UPFC constraints, where we implement custom Jacobian matrix formulations to handle the additional control variables. Key MATLAB functions include bus voltage initialization using polar coordinates, power mismatch calculations with UPFC injection terms, and iterative solution techniques for convergence. The implementation considers various operational scenarios through conditional programming structures, including system load variations modeled through parameter scaling and contingency analysis using fault impedance matrices. We demonstrate practical implementation techniques such as sparse matrix utilization for large-scale systems, callback functions for real-time control adjustments, and visualization tools for monitoring power flow redistribution. The code structure employs object-oriented programming principles for maintainability, with separate classes handling bus data, line parameters, and UPFC control logic. Through this approach, developers can create adaptable UPFC models that integrate seamlessly with existing power system simulation frameworks while maintaining computational efficiency through vectorized operations and optimized linear algebra routines.