One of the characteristics of modern interconnected power grids is susceptibility to change a local disturbance to a wide area disturbance. According to economical problems and development of power markets, power systems are operated near their stability limits. Wide area disturbances could result in blackouts with catastrophic effects. Due to increase in frequency and severity of power system blackouts in the world, study of wide area disturbances is important. One of the important element in this study is identification of involved factors which either contribute to spread or prevent further propagation of disturbances. Protective systems play a vital role in wide area disturbances. The relay systems sometimes prevent further propagation and sometimes contribute to the spread of disturbances. Thus in this thesis wide area disturbances are introduced and behavior of relays and protective systems during these disturbance are described. To give an explicit explanation to the subject, the IEEE 14 Bus test system was modeled in DIgSILENT Power Factory software and many scenarios in which operation of protective systems leads to blackouts are simulated and analyzed. Scenarios are left; MARGIN: 0cm 0cm 0pt; unicode-bidi: embed; DIRECTION: ltr" align=left Keywords: Wide area disturbances, wide area protection, collapse, blackout, power outage, distance protection
