POINT OF COLLAPSE AND CONTINUATION METHODS FOR LARGE AC DC SYSTEMS

This paper describes the implementation of both Point of Collapse (PoC ) methods and continuation methods for the computation of voltage coll apse points (saddle-node bifurcations) in large ac/dc systems. A compa rison of the performance of these methods is presented for real system s of up to 2158 buses. The paper discusses computational details of th e implementation of the PoC and continuation methods, and the unique c hallenges encountered due to the presence of high voltage direct curre nt (HVDC) transmission, area interchange power control, regulating tra nsformers, and voltage and reactive power limits. The characteristics of a robust PoC power flow program are presented, and its application to detection and solution of voltage stability problems is demonstrate d.