Description
MiCOM P141
Technical Specifications: Product type: Feeder overcurrent and earth fault protection relay Analog input: Three phase current and residual current CT inputs Auxiliary supply: Wide range DC auxiliary power Protection function: Phase overcurrent, earth fault, negative sequence overcurrent, thermal overload protection Binary I/O: Configurable digital input and relay output contacts Communication: RS485 serial port, optional Ethernet module Supported protocol: IEC 60870-5-103, Modbus RTU Operating temperature range: -20℃ ~ +60℃ Storage temperature range: -40℃ ~ +85℃ Relative humidity: 5% to 95%, non-condensing Mounting: Panel flush mounting Protection grade: Front face IP54, rear terminal IP20
Functional Features: Multiple configurable inverse time and definite time overcurrent protection curves. Sensitive earth fault protection for cable insulation breakdown and ground fault. Thermal overload protection to prevent feeder cable overheating damage. Fault event log and disturbance recorder to capture fault current waveform. Front panel LCD HMI and navigation keys for local status checking and parameter viewing. Time synchronization function for sequence of event recording. Configurable binary inputs to collect circuit breaker auxiliary contact status. Relay binary outputs for breaker trip, alarm and remote signal transmission. Power-on self-test and continuous hardware self-diagnosis function.
Application Scenarios: Medium voltage cable feeder protection, overhead distribution line protection, factory internal medium voltage power feeder, solar farm collection feeder, water plant medium voltage distribution cabinet, small substation feeder bay protection.
Performance Parameters: Fast fault detection and trip response for short circuit and earth fault. High stability protection curve calculation under fluctuating power system condition. Disturbance recorder captures pre-fault and post-fault waveform data. Continuous operation: 24 hours uninterrupted operation in substation control cabinet. High immunity to electromagnetic interference in power substation environment.
Material Composition: Front panel: Flame retardant reinforced plastic with polycarbonate LCD protective window. Main circuit board: Multi-layer FR4 glass fiber epoxy PCB with conformal coating. Core components: Precision sampling ADC, main CPU, non-volatile memory, communication transceiver chip, relay coils. Rear terminal block: PA66 flame retardant plastic screw terminals with tinned copper contact. Rear chassis: Steel metal shell for electromagnetic shielding.
Structural Features: Compact rectangular panel flush mount housing. Front panel fitted with LCD display, navigation buttons and status LED indicators. Rear side arranged with screw terminals for CT input, auxiliary power, binary input and relay output wiring. Internal circuit partitioned into analog current sampling area, digital processing area and relay output area. Metal rear casing provides shielding against substation electromagnetic interference. Side mounting lugs to fasten device to cabinet panel cutout.
Working Principle: Secondary current signals from feeder CT are delivered to analog input terminals of MiCOM P141. Internal sampling circuit converts analog current signal into digital data. CPU continuously compares measured current value with protection threshold and executes selected protection curve calculation. If fault condition persists beyond set delay time, relay output contact operates and sends trip signal to circuit breaker control circuit. All fault events and waveform data are saved to non-volatile memory. Communication interface transmits measurement and fault information to remote SCADA system. Local HMI supports operator to browse measurement value, fault records and device status.
Installation Requirements: Disconnect auxiliary power and CT secondary circuit before wiring operation. Insert relay into cabinet panel cutout and fasten side mounting lugs. Connect CT secondary cables, auxiliary DC power cable, binary input and trip output wires to rear terminals. Configure protection curve, threshold and time delay via relay configuration software. Set time synchronization parameter for event time stamp recording. Connect protective earth terminal to cabinet grounding busbar. Separate CT secondary wiring away from high voltage primary cables. Reserve maintenance space at cabinet rear side for terminal inspection.
Usage Notes: Save protection setting file before modifying relay parameters. Strictly avoid opening CT secondary circuit with primary line energized. Verify CT wiring polarity during commissioning. Check terminal screw tightness periodically under substation vibration environment. Wear anti-static wristband while handling internal circuit boards. Do not operate relay outside rated temperature and humidity range. Prevent dust and moisture accumulation on rear terminal block.
