Voltage Stability Assessment Based on Intelligent Techniques

Voltage stability is essential concern in electrical power systems. It will remain a challenge for the foreseeable future and, indeed, is likely to increase in importance because of the need for more intensive use of available transmission facilities. However there is no physical quantity which can tell the operator whether the system is secured sufficiently from voltage collapse. This book contains a new on-line approach to long-term voltage stability assessment applicable in practical power systems as well as an attempt to develop new approaches for voltage stability enhancement. On-line voltage stability scheme is based on combined artificial neural network (ANN) and fuzzy inference system (FIS) techniques. Enhancement approaches are based on ANN technique only. Four voltage stability assessment indices have been extracted analytically for large numbers of power system operating points to prepare feature matrices of ANNs. The extensive experience of the author in power systems makes a strong contribution to the formulation of the security criteria, the membership functions, the IF¿THEN rules of FIS decision-making, and countermeasures strategies to improve voltage stability.