Boundary Protection, A New Concept for Extra High Voltage Transmission Lines --- Part II: Discriminative Criterions and Simulations

This paper presents the discriminative criterions of the boundary protection for EHV transmission lines. The boundary protection relay consists of three parts, the start unit, the direction unit and the boundary unit. The fault discriminative criterions of the relay are based on the single-ended transient information extracted by the wavelet transform. The tests using EMTP simulations and recorded field-data demonstrate that the discriminative criterions are able to offer correct discrimination between internal and external faults for all system and fault conditions