Small signal security index for contingency classification in dynamic security assessment

This paper presents a security index for quantifying the small signal security of power systems. The index refers to the characteristics of system oscillation modes and delivers the degree of change in system security due to contingencies. The index can be of supplemental use in power system contingency screening and ranking. Moreover, the paper suggests the concept of aggregating the index with the established index for dynamic security inference. The aggregation concept allows individual application of each of the indexes in partial security investigations or application of both in the complete security investigations.