Fast three-phase reclosing method in shunt reactor compensated transmission lines

摘要

592858 Disclosed is a method for adaptive three-phase fast reclosing applied to shunt compensated transmission lines. A relay is calibrated to a factory setting default reclosing time adjusted to a high value, and the reclosing time is automatically reset to the high value after line opening. The voltage across the contacts of the switching device is measured via potential transformers and an envelope of the voltage across the circuit breaker contacts is measured. The envelope signal is then filtered to eliminate high harmonics. A circuit breaker opening instant, a first half-cycle of the filtered signal and a half-cycle semi-period of the filtered signal are then all identified. A beat period is determined after dead time and the circuit breaker reclosing time is adjusted, setting it equal to the beat period after dead time.