Programming Implementation of Newton-Raphson Power Flow and Short-Circuit Calculation for Three-Machine Nine-Bus Power System

This project implements numerical algorithms for Newton-Raphson power flow calculation and short-circuit analysis in a three-machine nine-bus power system. The MATLAB-based implementation includes comprehensive modeling of synchronous generators, transformers, transmission lines, and loads using admittance matrix formulation. The power flow algorithm employs the Newton-Raphson iterative method with polar coordinates, where the Jacobian matrix is updated at each iteration to solve the nonlinear power balance equations. Key functions include bus admittance matrix construction, power mismatch calculation, and voltage magnitude/angle updates. The short-circuit computation module implements symmetrical component analysis for fault current calculation at specified buses. The code structure features modular design with separate functions for: system data input, Y-bus formation, power flow iteration, fault analysis, and results visualization. Implementation details include sparse matrix techniques for efficient large-scale system handling and convergence criteria settings for numerical stability. Practical examples demonstrate the algorithm's application in calculating bus voltages, line power flows, and three-phase fault currents under different operating conditions. The simulation results help identify system vulnerabilities and optimize protection scheme settings, making this implementation suitable for both educational purposes and practical power system analysis.