Power system stability assessment using measurement based modal analysis

Abstract

Stability analysis of larger power system can be challenging and difficult. This is mainly due to the effect of several power system phenomena which are no longer negligible when the analysis is made on larger and complex power systems. The modelling of these unknown number of power system phenomena increases the overall model complexity. This causes the simulation more time consuming which does not help in improving stability of the system in the event of disturbance. Although, reduced order modelling of larger power system is considered as temporary solution, there is always a risk of producing different results than the actual power system response. In this thesis, various types of measurement based modal analysis is studied in detail as an alternate approach to the conventional model based modal analysis. This is based on the fact that any disturbance given to the system excites a particular eigenvalue pair/s causing significant reduction in damping ratio and thereby moving the system towards instability. These eigenvalue pair/s of each generator can be extracted directly from obtained system response using various mathematical techniques. Both time domain and frequency domain techniques are analyzed and compared with the results of model based modal analysis. Different IEEE test cases are considered based on the type of domain in which the data is analyzed.