Some Issues in Implementation of a Voltage Stability Analysis Function in an Energy Management System Environment

Over the last few years, the problem of voltage stability has received a lot of attraction from the power system community. This type of stability is now a major concern for utilities in both planning and operating conditions. Both static and dynamic aspects of the problem have been discussed and investigated by the researchers. The present paper concentrates on a Voltage Stability Analysis function as integrated into an Energy Management System (EMS) environment. In order to provide an optimal user interface, the function is integrated into the contingency analysis function. Key issues such as the integration approach, the voltage dependency of load characteristics, the choice of current point distance to critical point in terms of either MVAr, MW or MVA as well as a fast screening approach for finding the most potential unstable load nodes in an EMS are reviewed. The function has been implemented at the customer's NOK, Baden Switzerland-site in an on-line environment. Initial results are promising.