Digital teleprotection units. A technology overview

The authors describe a generic digital teleprotection unit (DTU) and discuss the technical characteristics of current commercial systems. A generic DTU contains a transmitter section, a receiver section and a status section. Some DTUs have a unidirectional option eliminating either the receiver section or the transmitter section. The transmitter section contains an input block, a transmitter logic block and a transmitter block. The receiver consists of a receiver block, a receiver logic block and an output block. The status section contains a selftest block and an alarm block. These subsystems are discussed. a comparison is made between DTUs and their analogue counterparts in the area of transfer trip delay. A direct transfer trip system utilizing redundant DTUs is proposed