Impacts of sizes of islands on the stability of a faulted power system

Abstract

Abnormal conditions in a power system create fluctuations to electrical quantities such as voltage, frequency and current. Some of them may lead to fall of system frequency and sometimes extreme abnormality leads to system blackout. Planned and proper islanding may protect the system from complete blackout even in case of extreme abnormalities. Islanding is the part of a power system consisting of generally one or more power sources and load, that is islanding is a situation in which a portion of the utility, comprising of both loads and generation sources, is isolated from the rest of the system for some period of time but remained energized. In case of emergency, islanding operation not only helps stabilizing a faulted system but also supports power supplies to critical and important loads. This thesis investigates the islanding technique, used to stabilize a power system under a severe condition and prevent blackout, with a view to develop a principle of the formation of islands. To do so the stability of a power system for different sizes (in terms of MW) and natures of islands such as load rich or generation rich are studied. The simulation results are compared to find a logical conclusion. In this study Bangladesh Power System (BPS) is considered. Islands of different sizes and natures are formed by disintegrating BPS. CYME PSAF (power System Analysis Framework) has been used for the simulation purpose. The investigation clearly shows that an island with higher inertia constant (H), performs better from the stability point of view.