An expert system for contingency analysis in power systems

An expert system is developed to determine the steady state security of a power system after a contingency. Line, transformer and generator outages are considered. For any load in the system, overloaded branches are determined by comparing the system load to three load levels closest to the actual system load and using generator shift or branch outage distribution factors. The expert system, in conjunction with the DC load flow, is designed to identify the harmless and harmful contingencies as well as the overload branches. If a contingency cannot be determined as harmless or harmful then an AC load flow is suggested. Turbo-Prolog is used for symbolic manipulations and reasoning. The developed system is applied to a 12 bus power system. The results indicate that the expert system can be used in contingency screening as well as online operation to assist the operator