Document Type : Research Paper


Faculty of Electrical and Computer Engineering, University of Tabriz, Tabriz, Iran,


This paper presents a new centralized adaptive method under frequency load shedding. Sometimes, after initial frequency drop following severe disturbances, although the system frequency returns to its permissible value, however, the system might become unstable due to voltage problems. In this regard, the paper proposes a new centralized adaptive load shedding method to enhance the voltage stability margin during under frequency conditions. Selection of loads to be shed in the proposed method depends on the loads’ power factor, generators reactive power output as well as the location of the disturbance. The proposed method is implemented on the dynamic simulated model of the modified IEEE 30-Bus test system and is compared with the conventional approach to confirm the applicability and effectiveness.