Asgar Poorghasemi Khiyavi - Department of Electrical Engineering Khalkhal branch, Islamic Azad UniversityKhalkhal, Iran
Farhad Zishan - Department of Electrical Engineering Ardabil branch, Islamic Azad UniversityArdabil, Iran

System stability study is the important parameter of economic, reliable and secure power system planning and operation. Power system studies are important during the planning and conceptual design stages of the project as well as during the operating life of the plant periodically. This paper presents the power system stability analysis for IEEE-9 bus test system. The fault is created on different busses and transient stability is analyzed for different load and generation conditions.The critical clearing time is calculated by using time domain classical extended equal area criterion method. The system frequency and voltage variation is observed for different fault locations and critical clearing time. The IEEE-9 bus test system is simulated and stability is analyzed on ETAP software.

transient stability; load flow study; load shedding;frequency stability; IEEE-9 bus test system; extended equal area criterion; critical clearing time; ETAP software