Impedance determination of 400kV Overhead Lines of Kosovo Power System

This paper focuses on determination of the power line parameters based on both calculation and measurement approaches. A separate analysis dedicated on the possible identification of the parameters causing incorrect distance relay protections operations, which may lead to power lines tripping and voltage and/or frequency instability is performed. To demonstrate the approach a case study with existing real life 400kV power line is performed [1]. For the test case identified the power line parameters are determined independently in three different ways using readily-available Matlab software tool, using direct measurement with professional instrument, and also using reference tabular values used by the transmission system operator. Based on the analytical comparison performed valuable conclusions and recommendations are provided.