A Directional Wave Detector Relay With Enhanced Application Capabilities for EHV and UHV Lines

A directional wave detector relay capable of fulfilling the high-speed or ultrahigh-speed (UHS) protection requirements for EHV and UHV transmission lines is described. The results of combining directional wave detection with a sequential measurement distance relay and a sensitive ground overcurrent unit are discussed. Multiple functions operating in series and parallel enhance the security and dependability by mutual support whereby the inherent strengths of each measurement technique are used to improve the characteristics of others. Solutions for difficult application problems are presented. In addition, economic considerations are noted for increased power transfer and reduced circuit breaker costs.