Technical Parameters Basic Identification Brand: Alstom / Areva / GE Grid Solutions Model: P127 CA0M111 Series: MiCOM P120 compact feeder protection range Application: Medium voltage feeder, distribution transformer, traction substation auxiliary bay primary/backup protection Auxiliary Power Supply Rated supply: DC 110V Operating range: 77 ~ 137.5 VDC Typical power consumption: ≤14 W Surge withstand: Class III overvoltage category, 2kV transient surge immunity CT Current Input CT secondary rated: 5 A, 50 Hz Phase CT burden: <0.8 VA per phase Residual earth fault dedicated current channel Core Protection Functions Two-stage phase overcurrent: IDMT inverse curves + definite instantaneous trip Sensitive residual earth fault two-stage protection Thermal overload cable/transformer thermal monitoring Broken CT supervision, trip circuit supervision alarm Undercurrent loss-of-load detection logic Binary Input & Relay Output Binary Input DI: 12 channels DC110V for breaker position, interlock blocking signals Relay Output DO: 8 heavy-duty mechanical guided relays AC-15: 250 VAC, 6 A inductive load DC-13: 110 VDC, 3 A trip coil breaking capacity Mechanical life ≥10,000,000 cycles; electrical life ≥100,000 full-load operations Recording & Measurement Event log: 500 time-stamped fault & alarm records Disturbance recorder: 40-cycle high-speed fault waveform capture Measurement accuracy: Class 0.5 for current sampling Communication Interfaces Rear isolated RS485: Modbus RTU, IEC 60870-5-103 Front RS232 maintenance port for local setting & firmware upgrade Mechanical Specs Mounting: Standard Size 2 flush panel mount Front panel: Backlit LCD, membrane keypad, multi-color LED status indicators, lockable transparent cover Wiring: Rear screw-clamp terminal blocks Overall dimensions: H160 × W144 × D215 mm Net weight: 1.25 kg Environmental & Compliance Standards Operating temperature: -25 ℃ ~ +70 ℃ Storage temperature: -40 ℃ ~ +85 ℃ Humidity: 5% ~ 95% non-condensing Vibration & shock: IEC 60255-21-1 substation anti-vibration standard EMC: Full IEC 61000-4 series immunity Certifications: IEC 60255, CE marked, RoHS & REACH compliant