A unified approach to processing unbalanced conditions in transient stability calculations

Based on the fault analysis by phase component method, a unified approach to processing unbalanced operating conditions in transient stability calculations is proposed in this paper. The method treats general faults and asymmetrical components under normal three-phase coordinates firstly, the model is then converted into the corresponding form in symmetrical component coordinates. Sequenced components are decomposed through equivalent matrix manipulations. The proposed method not only avoids complications for conducting sequence-network computation which is indispensable in traditional transient stability analysis, but also can be used to analyze unbalanced elements. Numerical results show that the method is accurate and efficient for transient stability calculations.