Feeder Protection Relay GE Multilin MIFIIPI11E1RHI00

onfigured for feeder overcurrent protection and circuit breaker control in electrical distribution networks, the GE Multilin MIFIIPI11E1RHI00 (MIF II Feeder Protection Relay) provides direct physical/electrical execution for phase and ground current monitoring, trip logic, and autoreclosing functions. Suffix Breakdown & Model MatrixHardware Specifications Parameter Specification Model MIFIIPI11E1RHI00 Brand GE Multilin Origin USA Weight 2.5 kg (5.5 lbs) Dimensions Standard drawout/panel mount enclosure (235 x 267 x 184 mm) Operating Temp -20 to +60 deg C Power Consumption Less than 10 W nominal Auxiliary Power Supply 110 to 250 VDC / 110 to 230 VAC (+/- 20%) Phase Current Input 1 A nominal ($I_n$) Ground Current Input 1 A nominal ($I_n$) System Frequency 50/60 Hz (+/- 3 Hz) Digital Inputs 2 opto-isolated inputs Output Relays 6 programmable output relays Serial Ports Front RS-232, Rear isolated RS-485 Communication Protocols Modbus RTU User Interface 2 x 16 character backlit LCD with 5-button keypad Process Control & Communication Interfaces The MIF II unit processes phase and ground AC signals through internal precision current transformers to calculate true RMS values for thermal overload, instantaneous overcurrent, and time-delayed overcurrent tripping functions. Channel-to-channel isolation between internal digital signal processing circuits, auxiliary power supply rails, and field current inputs ensures immunity to severe electromagnetic interference. Serial communication via the isolated rear RS-485 interface utilizes Modbus RTU protocol for remote integration with DCS and SCADA networks. Frequently Asked Questions Q: How is the front RS-232 port used during commissioning and maintenance? A: The front panel RS-232 port provides galvanic isolation for direct point-to-point connection with a PC running EnerVista M II setup software. It allows real-time telemetry monitoring, fault wave retrieval, and field firmware flashing. Q: Can setting groups be switched remotely during grid reconfiguration? A: Yes, the relay supports two distinct setting groups that can be toggled locally via the keypad or remotely via digital input status and Modbus RTU communication commands. Field Installation Guidelines Mechanical Installation: Mount the relay flush into a cut-out panel using the standard mounting brackets. Ensure adequate ventilation clearance around the top and bottom chassis heatsink channels. Grounding Connection: Connect the rear chassis grounding stud directly to the main station earth grid using a short, low-impedance braided copper strap (minimum 4 mm sq). CT Wiring Isolation: Wire secondary current transformer leads to shorting terminal blocks before connecting to the relay CT inputs. Maintain tight screw torque settings to prevent open-circuit CT hazards. Serial Shielding: Use twisted-pair shielded cable for the rear RS-485 bus. Ground the cable shield at a single point at the master station end to avoid ground loop circulating currents.