Complex-Variable Newton-Raphson Load-Flow Analysis with FACTS Devices

Based on complex voltage variables, the paper develops a Newton-Raphson (NR) load-flow analysis formulation which includes FACTS devices. Detailed analysis of the formulation confirms that significant reduction in memory access is achieved by the complex-variable NR formulation in comparison with the traditional formulation based on the real form. The significant reduction in memory access achieved will lead to the advantage of substantial reduction in computing time when load-flow analysis is implemented in parallel-computing environment. This advantage is also applicable in the case of single-processor computing environment, depending on memory cycle time. The formulation removes the approximation used in the previously-published NR load-flow analysis in complex form. The new method preserves fully the powerful convergence property of the NR algorithm. In addition, complex-variables offer a flexible and direct approach for modeling FACTS devices. The formulation is tested by simulation with representative power systems, including that with FACTS devices