Optimization of distance protection algorithm for series-compensated transmission line

This paper is focused on optimizing the distance protection algorithm for series-compensated line. This algorithm requires estimation of three-phase voltage drops across capacitors bank. For this purpose a nonlinear differential equation is solved on-line, applying comparatively low sampling frequency. In order to assure high fidelity of the waveforms reconstruction using the up resampling procedure has been introduced. The other interest of this paper is in impedance calculation based on optimal solution of the fault loop model. Two methods for fault loop resistance and reactance calculation are taken for comparison. The developed algorithms have been tested and evaluated using signals taken from ATP-EMTP versatile simulations of faults on a series-compensated transmission line. The sample results of the evaluation are presented and discussed.