Voltage Stability Analysis Of Interconnected Power System

Abstract

Voltage control and stability problems are not new to the electric utility industry but are now receiving special attention in many systems. Once associated primarily with weak systems and long lines, voltage problems are now also a source of concern in highly developed networks as a result of heavier loadings. In recent years, voltage instability has been responsible for several major network collapses. As a consequence, the terms "voltage instability" and "voltage collapse" are appearing more frequently in literature and in discussions of system planning and operation. Voltage stability is concerned with ability of a power system to maintain accept- able voltages at all buses in the system under normal conditions and after being subjected to a disturbance. A system enters a state of voltage instability when a disturbance, increase in load demand, or change in system condition causes a pro- gressive and uncontrollable decline voltage. The main factor causing instability is the inability of the power system to meet the demand for reactive power. This thesis illustrates the basic concepts related to voltage instability by rstly considering the characteristics of transmission systems and then examining how the phenomenon is in uenced by the characteristics of generators, loads, and reactive power compensation devices.