A smart instrument for on-line monitoring of static voltage stability index using local measurements

This paper describes a method of determining the static voltage stability index of a load bus using some local measurements as well as provides an overview of designing a smart instrument for on-line monitoring the stability index. The instrument requires only the bus voltage and current magnitudes at two distinct operating points to determine the stability index. In a real power system, the above information can easily be obtained through a potential transformer and a current transformer. The performance of the instrument is then tested on the IEEE 14- and 30-bus systems and very encouraging results are found. The voltage and current required in the instrument are obtained through load flow solutions. Random errors are also introduced in the load flow solutions to account for measurement errors in a real system.