Short-circuit current estimation from measurements of voltage and current during disturbances

Short-circuit current is usually calculated theoretically, using power network parameters and configuration. This paper describes a method for estimating the short-circuit current using measurements taken at the distribution feeders. The method makes use of small, as well as large, disturbances. As an example, the paper includes a statistical analysis of the short-circuit current estimates from disturbance measurements in a 20-h period near a sawmill. The short-circuit current value plays an important role in the evaluation of the severity of power quality degradation at the distribution voltage levels.