Online transient stability evaluation of interconnected power systems using pattern recognition strategy

Abstract

Common drawbacks with most of the fast stability assessment techniques are that system configurations and settings are often over-simplified; that load nonlinearities and control discontinuities cannot be easily modelled; and that there is no allowance made for interconnected system operating criteria. Using the method of pattern recognition, an online strategy has been developed for assessing the transient stability of interconnected power systems and for evaluating the security transfer limits between neighbouring systems. This strategy makes use of: (a) An online pattern database which contains vital system data for defining the stability of the interconnected systems. (b) An algorithm for retrieving information from the database, for online stability monitoring and assessment. (c) Control/steering algorithms using full-scaled transient stability simulations for offline training (creating) the database and retraining (updating). The online stability monitoring and assessment aspects of the strategy may be completed in a very short time since the main bulk of computations is done offline beforehand. Using a medium-sized interconnected transmission system as a test example, it is shown how the strategy has been effective for online applications.