Impact of post-fault noise on digital distance relays

Abstract EN

A technique is presented to determine the performance limits of digital distance relays.

The performance criteria are defined in terms of “assured tripping zone” for internal faults and “optimal secured reach” for external faults under all possible noise conditions.

In contrast to some previously published techniques which utilize different estimation methods, the presented technique uses mathematical programming for determining the performance limits.

Simulation results are presented for a digital distance relay.

The results, while confirming the known general trends regarding the impact of noise on relay performance, provide quantitative values for the performance limits of the simulated digital distance relay for specified noise bounds.