A Computation Algorithm for Assessing Voltage Stability at AC/DC Interconnections

A new method for the analysis of ac voltage stability problems at HVDC terminals, when imbeded in large networks, is presented. The method can be used to evaluate the effects of dc modes of operation, ac system operating conditions and VAr compensation schemes on the combined system voltage stability. Dynamic properties of both ac and HVDC systems are incorporated in the solution algorithm. A step-by-step technique is developed for integrating the new algorithm with available load flow programs. Examples are given to demonstrate the performance of a new control strategy for HVDC converters connected to weak ac systems and the results are compared to classical solutions.