Description

GE Multilin L90 Line Current Differential Protection System

Configured for high-speed line current differential protection in GE Universal Relay (UR) platforms, the GE Multilin L90 (L90 Line Current Differential Protection System) provides direct physical/electrical execution. The relay performs synchronized current vector exchange, protection logic processing, control output operation, and substation communication functions for transmission and sub-transmission line applications.

Hardware Specifications

Parameter	Specification
Model	GE Multilin L90
Brand	GE Multilin
Origin	Canada
Dimensions	19-inch rack mount chassis, 4RU height; 1/2 rack or full rack width options
Operating Temp	-40 deg C to +60 deg C
AC Current Inputs	1 A or 5 A nominal CT inputs; burden less than 0.2 VA at nominal current
AC Voltage Inputs	50 V to 240 V nominal phase-to-neutral; burden less than 0.15 VA at 120 V
Frequency	50 Hz or 60 Hz nominal; operating range 20 Hz to 65 Hz
Control Power Supply	88 VDC to 300 VDC or 88 VAC to 265 VAC; optional 24 VDC to 48 VDC
Digital Inputs	Opto-isolated inputs with programmable voltage range
Output Relays	Form-A and Form-C dry contacts; fast solid-state output options
A/D Conversion	64 samples per cycle, 16-bit resolution
Communication Interfaces	Direct fiber, C37.94, G.703, RS422, Ethernet, IEC 61850, DNP3, Modbus TCP/RTU

Deterministic Industrial Communication and Control Interfaces

The GE Multilin L90 supports deterministic network communication through Ethernet and serial interfaces for protection data exchange and substation automation. The relay supports IEC 61850 Edition 1 and Edition 2, GOOSE messaging, MMS services, DNP3, Modbus TCP/RTU, and IEC 60870-5-104 protocols.

The Universal Relay platform architecture supports backplane bus communication velocity licensing, Profinet / EtherNet-IP deterministic network concepts, I/O density scaling, and firmware flash compatibility management across compatible hardware configurations. The L90 uses synchronized sampling and communication channel compensation to maintain differential protection calculations during line fault conditions.

Frequently Asked Questions

Q: Does the L90 support multi-terminal line protection configurations?
A: Yes. The L90 supports two-terminal and three-terminal line configurations with current differential protection channel communication between relay locations.

Q: What communication media are available for 87L current differential channels?
A: Supported media include direct fiber optic connections, C37.94, G.703, and RS422 interfaces depending on the installed communication module configuration.

Q: Can the L90 execute breaker control functions without an external PLC?
A: Yes. The relay includes FlexLogic programmable logic for internal control sequences, breaker failure logic, synchrocheck, and autoreclosing functions.

Field Installation Guidelines

Install the L90 in a suitable protective relay panel or rack enclosure with correct mechanical support for the selected rack configuration. Maintain separation between CT/VT wiring, control wiring, and communication cables to reduce electrical interference.

Terminate current transformer circuits according to protection engineering practices, maintaining correct polarity and phase identification. Use shielded communication cables where applicable and connect cable shields according to site grounding standards.

Verify fiber optic connections, Ethernet port assignments, time synchronization inputs, and communication channel settings before commissioning. Confirm relay firmware compatibility with the installed hardware modules before performing configuration updates.

Specifications

• Brand: General Electric

Advantages

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