Phase-to-phase distance protection for pilot scheme (85) The relay provides an independent zone for pilot scheme of PUTT, POTT, Blocking, Unblocking, DTT & Zone Extension. The scheme integrates current reversal logic, weak-infeed echo and open breaker echo. Protective relays and devices have been developed over 100 years ago to provide “lastline”of defense for the electrical systems. They are intended to quickly identify a fault and isolate it so the balance of the system continue to run under normal conditions. The selection and applications of. The NR PCS-902 relay provides numerical line protection with pilot distance protection, stepped distance protection, current protection, voltage protection, single and/or threepole tripping and auto-reclosing functions. As a full-schemedevice, it integrates frequency protection, breaker failure. The PCS-902 provides comprehensive protection and control solutions for transmission lines with high-speed sub-cycle distance element.
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