DISTANCE PROTECTION RELAY LFZR 111 / LFAA 101 ALSTHOM

The LFAA auto-reclose relay provides facilities for single or two-shot reclosures of one or two circuit breakers following their tripping for a fault on an overhead line. The reclosures can be selected to be either high speed single-phase, or high speed or delayed three-phase. When three-phase reclosure is desired the equipment will convert any single or two-phase LFZR111 Provides single phase or three phase tripping with selectable DEF protection. It can use shared or independent signalling channels. tripping into three-phase tripping before initiating the reclosure. For schemes with two circuit breakers the reclosure of the second circuit breaker can be either simultaneous with the first circuit breaker or it can be sequential. In the latter case the reclosure of the second circuit breaker must naturally be a delayed three phase reclosure. ONE BREAKER SCHEMES ( LFAA 101) > Single shot scheme: ï ¿ ½ single phase auto-reclose ï ¿ ½ single phase or three phase ï ¿ ½ auto reclose, depending on type of fault ï ¿ ½ three phase auto-reclose for all types of fault > Two shot scheme: Any of the above cycles for the first shot, followed by delayed three- phase auto-reclose if protection re- operates during the reclaim time after the first reclose TWO BREAKER SCHEMES ( LFAA 102) > Combinations of single and three phase auto-reclose as above > Circuit breakers can be closed simultaneously or sequentially on the first shot