PROJECT TITLE :

Adaptive Direct Underreaching Transfer Trip Protection Scheme for the Three-Terminal Line

ABSTRACT:

The direct underreaching transfer trip (DUTT) scheme used for the protection of the three-terminal transmission line operates when a minimum of one among the 3 zone one components detects an internal fault. This scheme uses a passionate communication system to transfer the decision from one end to the opposite ends. The DUTT theme is reliable until the overlappings between zone one settings are ensured. The infeed through the tapped line reduces the overlappings between the zone 1 parts in the DUTT theme. At times, the zone 1 overlappings of the 3 distance relays vanish, which leaves an unprotected region in the theme. During this paper, an adaptive DUTT scheme is proposed where overlappings of zone 1 settings are calculated using prefault synchronized data, and relay settings are updated whenever needed to confirm a correct protection decision. The proposed adaptive method is tested for a three-terminal line simulated in EMTDC/PSCAD and also the results show its high accuracy.