Block-Based Selected Inversion for Computing Three-Phase Selected Short-Circuit Currents in Large-Scale High-Voltage Power Systems

Computing three-phase short-circuit currents (3pSCCs) in large-scale high-voltage power systems needs to find the inverted nodal admittance matrix, which is generally time-consuming. However, it is unnecessary to obtain the full inverted matrix if only calculating selected 3pSCCs at some critical nodes. This letter proposes a block-based selected inversion algorithm. It targets selected elements to construct a block tridiagonal matrix, and obtains these selected elements of the inverted matrix by calculating the inverse of the selected block within the block tridiagonal matrix. Simulation results demonstrate that this approach significantly accelerates the computational speed while guaranteeing the high solution accuracy.