Optimal reactive power allocation for power system transfer capability assessment

Power system stability issues have always been of utmost importance and interests. Since the restructuring of power utilities, electric power systems have been strained to operate under much higher stress levels, and closer to their physical and operational limits. Thus system instability issues have become increasingly critical, and are of primary concern during power system operation and planning. This paper investigates the impacts of reactive power re-dispatching and reactive power compensation on static voltage stability margins when evaluating power transfer capability. A mix-integer nonlinear programming (MINLP) problem formulation is proposed here not only to re-distribute reactive power, but also to effectively determine optimum locations and amount of both series and shunt reactive compensation. The well-known branch-and-bound based technique is being employed and tested on a simple test system. Results showed significant enhancements to system static voltage stability margins