Effective transient stability assessment based on composite indices

Abstract

This paper presents a new composite index to analyze power system transient stability. Contingency ranking in power system transient stability is a complicated and time consuming task. To prevail over this difficulty, various indices are used. These indices are based on the concept of coherency, transient energy conversion between kinetic and potential energy and three dot products of the system variables. It is well known that some indices work better than others for a particular power system. This paper along with test results using two practical 230 kV Sistan and 400 kV Khorasan power system in Iran, and 9 bus IEEE test system demonstrates that combination of indices provides better ranking than a single one. In this paper two composite indices ( CI ) is presented and compared. One composite index is based on Least Mean Square algorithm (LMS) and other based on summing indices by equal weights. Numerical simulations of the developed index, demonstrate that composite index is more effective than other indices.

Keywords

• composite index
• transient stability
• energy margin.