Automatic control of voltage instability by an expert system utilizing pattern recognition techniques

The authors describe a knowledge-based algorithm for automatic control of extreme disturbances that could lead to system voltage instability. The study results show that it could adapt for quite different types of disturbance-be it loss of lines or loss of generation-to sustain system voltage stability. A new methodology has been developed that utilises the pattern recognition method in the areas of reactive power control following a contingency. Based on this new methodology, the operators can be provided with a priority list for searching the best available control measures after each contingency. The consequence of each chosen control measure can be predicted beforehand. The algorithm makes use of the knowledge about the system, sensitive factors, operating rules, operator´s experience and other requirements for good system operation