On-line Transient Stability Detection Using Intelligent Systems with Energy Functions Based Inputs

In this paper, for on-line Transient Stability Assessment (TSA), two sets of intelligent units are used. Set 1 consists of one intelligent unit which estimates Critical Clearing Time (CCT) for each contingency. The inputs of this unit are maximum potential energy, minimum kinetic energy and the slope of minimum kinetic energy. To determine these inputs, 0.5 to 0.7 seconds of the system response has to be simulated. To estimate CCT more quickly, the inputs of the intelligent unit in Set 1 are estimated using three other intelligent units (Set 2). At first, the inputs of intelligent units in Set 2 are selected from both measurable and non-measurable variables. Simulation results show that in this case CCT is determined through simulating only 0.05 seconds of the system response. This indicates the suitability of the proposed method for on-line pre- disturbance TSA.