GE Multilin 489-P5-LO-A20-E Generator Management Relay

Description

The GE Multilin 489-P5-LO-A20-E Generator Management Relay is a digital protection, monitoring, and metering device designed for small to medium-sized synchronous or induction generators operating at 25 Hz, 50 Hz, or 60 Hz. As a member of the SR family of relays, this system features a draw-out construction and delivers advanced protection algorithms, including generator stator differential protection and 100% stator ground fault detection.

The unit manages thermal modeling using 12 RTD inputs, processes vibration/speed inputs via 4 analog transducer channels, and supports continuous operational logging with oscillography and event recording. Integration with industrial DCS and SCADA architectures is facilitated through front RS232, dual RS485, and 10BaseT Ethernet communications supporting Modbus RTU, Modbus TCP/IP, and DNP 3.0 protocols.

Features

• High-speed dual slope differential protection with CT saturation detection algorithms.
• 100% stator ground protection via overvoltage and adaptive voltage differential elements.
• Thermal overload modeling incorporating current unbalance biasing and RTD thermal feedback.
• 12 field-programmable RTD inputs supporting Platinum, Nickel, and Copper sensors with RTD voting functionality.
• 4 isolated 4 to 20 mA analog transducer inputs for bearing vibration and speed tracking.
• 4 active 4 to 20 mA analog outputs for parameter signaling to PLCs.
• Integrated oscillography capturing 12 samples per cycle for up to 128 cycles.
• Time-synchronized event recording up to 256 events via IRIG-B clock inputs.
• Front panel interface featuring a 40-character display, numeric keypad, and 22 status LEDs.
• Low-range control power supply accepting 20 to 60 VDC or 20 to 48 VAC.

Applications

• Primary or backup generator protection for synchronous and induction machines.
• Stator, bearing, and excitation monitoring in cogeneration facilities.
• Industrial power generation systems operating at 25 Hz, 50 Hz, or 60 Hz nominal frequencies.

Ordering Information

Technical Specifications

Connections/Interfaces

Installation Guidelines

• Grounding: Connect safety ground and filter ground terminals independently to the main station ground bus to satisfy noise rejection and safety standards.
• Wiring Safeguards: Ensure CT connections pass through automatic shorting terminals before servicing or removing the draw-out unit.
• Control Power Matching: Confirm that the supply voltage matches the low-voltage range (20 to 60 VDC / 20 to 48 VAC) prior to applying power to terminals G10-G12.
• Shielding & Interference Mitigation: Route RTD and analog transducer signal cables using twisted-pair shielded conductors, grounding the shields exclusively at the designated shield terminals.
• Communication Lines: Terminate RS485 networks with 120-ohm resistors and 1 nF capacitors at both ends of the loop.

Compliance and Certifications

• ISO: Manufactured under an ISO9001 registered system.
• CSA/UL: Certified to UL508, UL1053, and CSA C22.2 No. 14 standards.
• CE: Conforms to EN60255-5 and EN50263 standards.
• Type Tests: Complies with IEC 61000-4 series, EN60255 series, IEEE/ANSI C37.90.1, C37.90.3, and CISPR11/22 requirements.