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® WorleyParsons <br /> resources&energy <br /> • Power transformers (each GSU and UAT) <br /> — Transformer differential relay(87T) or overall unit differential (87U) <br /> — Transformer neutral overcurrent(51 TN) <br /> — Transformer phase instantaneous overcurrent (50) <br /> — Transformer phase time overcurrent (51), other than main step-up transformers <br /> — Restricted ground fault protection(87GD)—Unit auxiliary transformer low voltage <br /> windings only. <br /> — Transformer fault pressure relay (63) <br /> — Oil level switch (7IQ) (alarm only) <br /> — Oil temperature (26Q) (alarm only) <br /> — Winding temperature (49) (alarm only) <br /> — Overpressure (alarm only) <br /> — Main step-up and unit auxiliary transformer protection relays will be SEL-387E or <br /> equal. <br /> • MV buses (4.16 kV) <br /> — Bus under voltage for alarm(27) and blown secondary VT fuse indication (60) <br /> — Incoming phase time overcurrent(5 1) <br /> — Incoming residual ground time overcurrent (51 G) <br /> — Bus ground fault detection(59G) on the MV busses to detect bus faults prior to <br /> closing the generator breaker. <br /> • 4.16-0.480kV transformers (protection located in the 4.16kV switchgear) <br /> — Phase time overcurrent (5 1) <br /> — Phase instantaneous overcurrent(50G—zero sequence) <br /> • 4000 V motors <br /> — Thermal overload(49) <br /> — Phase overcurrent (5 1) <br /> — Phase instantaneous overcurrent(50—provided by contactor fuse) <br /> — Ground overcurrent (50G - zero sequence) <br /> — Phase reversal (47) <br /> — Stator overtemperature (when required by the P&IDs) (alarm and trip) <br /> — Bearing overtemperature (when required by the P&IDs) (alarm only) <br /> — Phase current unbalance (provided through thermal overload protection) <br /> — Vibration (when required by the P&IDs) (alarm and/or trip as indicated by P&IDs) <br /> • LV switchgear buses (480 V) <br /> — Bus under voltage for alarm and blown secondary VT fuse indication <br /> — LT/ST protection on main, tie, and MCC feeder breakers <br /> — LT/ST/I protection on motor feeders <br /> — Ground fault alarm <br /> Lodi Energy Center 3.4-9 LEC AFC <br /> 071608 Rev.A <br />