Power system state estimation using wire temperature measurements for model accuracy enhancement

Power system state estimation is a process of real-time online modeling of an electric power system. The estimation is performed with the application of a static model of the system and actual measurements of electrical quantities that are encumbered with error. Usually, a model of the estimated system is also encumbered with uncertainty, especially power line resistances that depend on the temperature of conductors. Presently, a considerable development of technologies for dynamic power line rating can be observed. Typically, devices for dynamic line rating are installed directly on the conductors and measure basic electric parameters such as current and voltage as well as non-electric ones as surface temperature of conductors, their expansion, stress or the conductor sag angle relative to the plumb line. The objective of this article is to present a method for power system state estimation that uses temperature measurements of overhead line conductors as supplementary measurements that enhance quality of the model and thereby the estimation accuracy. Power system state estimation is presented together with a method for using temperature measurements of power line conductors for updating the static power system model in the state estimation process. Results obtained with the application of that method have been analyzed based on the estimation calculations performed for an example system with and without taking into account the conductor temperature measurements. The final part of the article includes conclusions and suggestions for the further research work.