The heart of the data processing activities of a modern electric utility energy control center is the power system state estimator. A state estimator provides the same information on-line that are provided by a load flow study off-line. This information is used for contingency evaluation, security assessment, control strategy and economic dispatch. An energy control center gathers information on the state of a power system that may include large errors which called bad data. In view of the above consideration, it is necessary to have a method to establish a reliable and complete data base for...