A Survey of the Recent Developments in the Traveling Wave Differential Protection Element in Protective Relays

Recent advancements in signal processing, communication, and measurement technologies have facilitated the development of time-do main-based protective relays (TDRs). The adoption of these relays is growing in the U.S. power grid due to their significant enhancements in fault detection and location speed and precision. Out of the several time-do main- and traveling wave (TW)-based elements in these TDRs, the TW differential (TW87) element provides fault detection at ultra-high speed. This paper provides a survey of the recent developments in this protective element, as well as a summary of the performance of these relays based on field results, hardware testing, and simulation-based studies conducted in literature.