Stability analysis based on bifurcation method : a case study of Lakvijaya power station, Sri Lanka

Abstract

The power system is a dynamic system, which consists of nonlinear elements. Generally, methods based on linearization are sufficient to analyse the system under both normal operating conditions and perturbations of the variables. However, due to the stressed operating conditions, system behaviour is highly influenced by the nonlinear elements of the system. Therefore, analysis based on linearized methods is not sufficient to understand the system behaviour under such conditions. In this thesis, a nonlinear analysis is carried out based on bifurcation theories to identify the system behaviour more accurately. The case study considers the effect of integrating the Lakvijaya power station to the Sri Lankan power system, which can be considered as a small system. Dynamic voltage stability assessment based on bifurcation analysis for both intact and contingency conditions were carried out for a system under consideration. The critical state variables for a bifurcation were identified and mitigation criterions are suggested.