Ultra - High - Speed Relaying Protection: Asetting Methodology

An in - death analysis of fundamental Parameters Pertaining to Ultra-High-Speed Relay (UHSR) settings is carried out. The performance of the Independent Directional Detector (DD1) unit is analyzed in terms of the setting application values of current and voltage for a variety of faults and systems conditions. Relative underreach curves are presentes to show the influence of fault type and resistance on the unit detection range for a given setting. The paper describes a setting approach, based on the above analysis, as actually implemented in a 500 KV double circuit line, with a fuller utilization of the independent mode.