On-line dynamic-security contingency screening and ranking

An on-line dynamic-security contingency screening and ranking system for large complex power systems, online algorithms for system-instability studies (OASIS), has been developed which is intended to provide a list of ranked contingencies for the current operational state of the power system every lj min. A highspeed power-system simulator is used to predict, in real time transient and dynamic stability from any initial power-system state together with an appropriate contingency list, OASIS uses a client/server model and is designed to run on a heterogeneous computer network to avoid any limit to system size. The prototype of the assessor was completed in mid 1994 and field trials were carried out within an operational power-system-control centre using real online data taken from the system energy-management system. Implementation of OASIS and the results of the field trials are described.