Determination of Transient Stability Constrained Interface Real Power Flow Limit Using Trajectory Sensitivity Approach

Fast determination of the transient stability constrained interface power transfer limit is a critical problem in power system real time operation. Conventional methods normally require repeated time domain simulations to determine this interface transfer limit; therefore, they are computationally burdensome and time consuming. This paper presents an application of the trajectory sensitivity method to determine the transient stability constrained interface transfer limit. For a specified contingency, the trajectory sensitivity method is used to determine the stability constrained maximum output of the key generators that affect the power flow of the interface. Then using the power transfer distribution factors (PTDFs) of those key generators on the tie-lines constituting the interface, the maximum interface transfer increment can be determined. The advantage of this method is that it requires much less computation compared to the conventional methods while having the same level of accuracy. An application of the proposed method to the WECC test system is presented in detail. The results obtained demonstrate the efficiency and accuracy of the proposed method.