Rotor angle small signal stability assessment in transmission network expansion planning

Transmission network expansion planning involves various types of static and dynamic analyses. The complexity and increasingly difficult operating conditions of power systems raise the importance of dynamic analyses on the expansion planning stage. Primary studies in the field of dynamic analyses include rotor angle stability, voltage ride-through and frequency stability analyses. This paper presents four methods of rotor angle small signal stability assessment, which can be used in transmission network expansion planning. For each of these methods, the requirements for the calculation model and computational accuracy are discussed, among other aspects. Practical considerations related to the use of particular methods in planning analyses are presented. Theoretical considerations are illustrated with the results of stability assessment of a multi-machine test system.