Negative Sequence Changes Calculation for Purposes of Fault Localization

This paper is focused on calculation of negative sequence changes of voltage and current from distributed measurement. These changes are necessary for evaluation of a new fault localization method Vdip. A principle of changes calculation is described, and problems affiliated with phasor estimation are discussed. Solutions for suppressing major disturbances, such as frequency deviation and interharmonics, are suggested. A way of cancelling out interharmonics based on averaging in sliding windows is presented. Eventually, a calculation procedure is formed, and performance of individual proceedings is tested. The analysis shows that optimized setting of time frames, from which the changes are calculated, is essential to mitigate negative impacts of the major interharmonic frequencies, and can substitute utilization of digital filtering.