Impact of Series Compensation on Alpha Plane Line Current Differential Protection Scheme

This paper presents an impact of series compensation on alpha plane line current differential protection scheme. Though series capacitors are applied in the transmission line to maximize the overall power transfer, they cause voltage and current inversion, which results in change in phasors. Nowadays, due to the installation of wide-area measurement system and phasor measurement unit technology at various substations, utilization of the concept of alpha plane characteristic in differential protection is gaining momentum. Although the application of the said concept at transmission-level yields many advantageous, it may suffer from several challenges due to variable compensation level and location of the series capacitor. In this paper, the impact of said parameters on the conventional alpha plane characteristic has been studied by modeling a series compensation transmission line in PSCAD/EMTDC software package.