Evaluation of Capacitive Current Compensation Strategies to Current Differential Protection for Long Distance Transmission Lines

Abstract

In UHV and EHV, distributive capacitive current to current differential protection has serious problem. Nowadays, to deal with the problem of distributed capacitive current a stimulating modern technology is being used in current differential protection with high operating threshold. Many schemes have been used into current differential protection for capacitive current compensation, which was based on shunt reactor, phasor compensation algorithm, Bergeron method. Those techniques were also reducing operating speed and sensitivity of current differential protection. To solve the problem of distributed capacitive current of the line, novel principle of current differential protection is described in this article. Current calculated from set point to both the ends give rise to a differential criterion. Differential protection is launched under the phenomenon of low sampling frequency to improve the expediency of the criterion. The calculation of set point distributed current is achieved at low sampling frequency by adding an interpolation point at each sampling interval. The point is set in the middle of the line and the calculation for magnitude of the current is done with half data window absolute value integrals, for improved the operating speed of the current differential protection.