Newly developed voltage security monitoring system

A voltage security monitoring system has been developed and installed in the energy management system of TEPCO´s (Tokyo Electric Power Co.´s) central energy control center. The authors present the background and concept of the developed system, the newly developed algorithm, the configuration of the system and results of actual operation. A PV (total demand, voltage) curve is used for estimating voltage stability. To determine the curve, an algorithm for obtaining multiple load flow solutions is developed. The system has been in operation since February 1990, running at intervals of one minute