Description

GE Multilin SR489-P5-HI-A20 Generator Management Relay

The GE Multilin SR489-P5-HI-A20, also cataloged as the SR489 Generator Management Relay, operates as a dedicated hardware component for generator protection, metering, monitoring, and control within GE Multilin 489 Generator Management Relay platforms.

Hardware Specifications

Parameter	Specification
Model	SR489-P5-HI-A20
Brand	GE Multilin
Origin	General Electric
Dimensions	Compact drawout relay case; dimensions not specified
Operating Temp	Operating temperature not specified
Power Consumption	Typical 15 W, Maximum 35 W
Product Type	Generator Protection Relay
Power Supply	70-265 VAC (48-62 Hz) / 88-300 VDC
Current Inputs	5 A secondary phase current inputs
Current Input Frequency Range	20 Hz to 70 Hz tracking range
Current Input Burden	Less than 0.2 ohm at 5 A
Thermal Withstand	Continuous 10 A; 1 second 500 A
Voltage Inputs	50 V to 240 V AC phase-to-neutral direct or VT connected
Analog Outputs	4 programmable 4-20 mA DC outputs
Analog Output Load	Maximum 1200 ohm at 24 VDC external loop or internal supply
Communication Interface	2 x RS485 ports with Modbus RTU protocol
Communication Baud Rate	Up to 19,200 bps
Front Panel Interface	40-character backlit display, LED status indicators, programming keypad
Emissions Compliance	Class A radiated and conducted emissions
RF Immunity	Level 3

GE Multilin Generator Protection Processing and Control Functions

The SR489-P5-HI-A20 applies microprocessor-based numerical processing for generator electrical protection functions. The relay supports phase current measurement through 5 A secondary CT inputs and voltage measurement through VT secondary inputs. Protection elements include phase overcurrent, ground overcurrent, phase differential, and loss of excitation impedance functions.

The relay supports configurable ground overcurrent curves including ANSI, IEC, IAC, Flexcurve, and definite time characteristics. Loss of excitation protection is implemented with two impedance zones using impedance circles for generator field monitoring. High set phase overcurrent timing accuracy is specified as +/-50 ms at 50/60 Hz or +/-0.5% total time.

Frequently Asked Questions

Q: Does the SR489-P5-HI-A20 support hot-swapping during operation?
A: The relay is installed in a drawout case configuration. Hot-swap capability is not specified in the provided technical data; isolation and controlled removal procedures should be followed during maintenance.

Q: What communication interfaces are available on the SR489-P5-HI-A20?
A: The relay provides two RS485 serial communication ports using Modbus RTU protocol with baud rates up to 19,200 bps.

Q: What analog output configuration is provided by the A20 option?
A: The A20 option provides four programmable 4-20 mA DC analog outputs for external monitoring and control circuits.

Field Installation Guidelines

Install the SR489-P5-HI-A20 in the designated relay mounting assembly with appropriate mechanical retention of the drawout case. Verify CT secondary wiring polarity and terminal integrity before energizing the protection circuit.

Maintain separation between current transformer wiring, voltage transformer wiring, communication cables, and high-energy conductors to reduce electrical interference. RS485 communication wiring should use shielded twisted-pair cable with the shield connected according to the plant grounding practice.

Confirm the control power supply matches the HI option input range before connection. Protective grounding, panel bonding, and enclosure wiring should comply with the applicable industrial electrical installation standards.

Specifications

• Brand: General Electric

Advantages

• High reliability in industrial environments
• Supports continuous operation
• Compatible with major PLC/DCS systems