FUZZY ASSESSMENT OF POWER-SYSTEM TRANSIENT STABILITY LEVEL BASED ON STEADY-STATE DATA

Following extensive analysis of the relationships between the transien t instability behaviour of large-scale power systems and the correspon ding prefault operating states, a novel heuristic method based on fuzz y reasoning is proposed in the paper for the fast evaluation of the po wer system transient stability level (TSL). A notable feature of this method is that it does not rely on the step-by-step simulation process and only system load-flow data under normal operating conditions are used for the assessment. A generalised critical clearing time (GCCT) i s defined that can be predicted by the proposed method to describe the TSL. Digital simulations based on two power systems show that the pro posed method provides broadly conclusive and decisive real-time inform ation about the stability states of the studied power systems.