NEWTON-RAPHSON ALGORITHM FOR THE RELIABLE SOLUTION OF LARGE POWER NETWORKS WITH EMBEDDED FACTS DEVICES

A new and efficient algorithm for the reliable load flow solution of p ower network branches controlled by flexible AC transmission systems ( FACTS) is presented. General admittance-based models are given for ser ies compensators, phase-shifters and tap-changers. Their inclusion in a Newton-Raphson load flow exhibiting quadratic convergence is describ ed and the prowess of the algorithm is demonstrated by comparison with production-grade load flow programs where the state variables of the controllable devices are updated at the end of each Newton-Raphson ite ration. Control coordination and initialisation strategies for the con trolled branches and nodes have been thoroughly investigated.