The L90, a member of the UR family of protection relays, is a digital current differential relay system which provides protection for transmission lines. It may be applied on or adjacent to series compensated lines for three phase tripping. The L90 utilizes an innovative current differential scheme with adaptive restraint that allows the relay to operate correctly even when fault currents are distorted by harmonics or CT saturation. Models are available for application on transmission lines with 2 or 3 terminals. The relay may be used as a standalone device or as a component of an automated substation control system.

What's New in the L90:

• Fully Compatible with GE Multlilin's HardFiber System - Provides support for GE's IEC 61850 HardFiber Process Bus Solution:
  - Complete IEC61850 Process Bus Solution providing resource optimization and minimizing total P&C lifecycle costs
• Security Enhancements - Enabling NERC CIP compliance:
  - Dual Permission access requiring live permission from both the user and from SCADA operators before settings can be changed or commands can be given to the relay
  - Logging of user commands in the security audit trail relay - creates a record and sequence of events for troubleshooting and security auditing
• Ambient Temperature Monitoring:
  - Provides alarms when the ambient temperature exceeds hot extreme

• Enhanced single-pole tripping applications using multi-bit communications schemes
• Reliable operation on Series Compensated Lines
• Three zones of back-up distance
• FlexLogic™ programmable logic
• Virtual I/O (reduce hardware cost)
• Expandable I/O
• Flash memory for field upgrades
• Optional user programmable pushbuttons
• User programmable LEDs, fault reports, display messages, and self tests
• Drawout modules for serviceability
• Common modules (reduce spare cost)
• Test mode for I/Os
• IRIG-B time synchronization and repeater

• Protect overhead AC transmission lines of any voltage level; including series compensated lines, with single and three pole tripping.
• Applicable for lines with 2 or 3 terminals.
• Fiber optic and electrical (RS422, G703) interface via direct or multiplexed fiber optic
• Integrated line current differential protection and phasor measurement units.

• The L90 utilizes an innovative current differential scheme with adaptive restraint that allows the relay to operate correctly even when fault currents are distorted by harmonics or CT saturation
• Enhanced single-pole tripping applications using multi-bit communications schemes
• Reliable operation on Series Compensated Lines
• Three zones of back-up distance
• Directional wattmetric zero sequence protection function for distribution systems earthed via Peterson coils
• Directional phase, neutral and negative sequence current functions, under/over voltage function
• Secure operation during external faults
• 512 lines of protection logic - build custom protection schemes of your choice
• Tripping without Logic for direct tripping without the need for configuring Flexlogic Equations
• Double Point Breaker/Switch Status

• Easily meet stability requirements - High speed single/three pole tripping and reclosing
• Dependable - Globally accepted, with performance backed up by many years of field experience
• Maintenance cost savings and simplification - Modular construction, common hardware, reduced stock of spare parts, plug & play modules

• Application flexibility - Multiple I/O options, programmable logic (FlexLogic™), modularity, customize to specific requirements
• Reduce installation space requirements through compact design - Multifunction device that integrates protection and control functions, programmable pushbuttons and status LEDS, and communication interfaces

• Reduce system event analyzing time and cost - Sequence of event reports, Oscillography, data logging, IRIG-B time synchronization
• Comprehensive metering functionality
• Synchronized measurement of voltage & current fundamental and sequence component phasors at user programmable streaming rate of 1 to 60 phasors/sec - Integrated PMU and Protection
• Advanced device health diagnostics - Designed to detect relay health on a continuous basis and alarm operators on the criticality of the issue

• Front Panel RS232 port
• Up to two RS485 ports (up to 115 kbps)
• Ethernet port: Redundant 10BaseFL or 100BaseFX fiber optics
• Embedded Ethernet Switch for direct networking of UR devices
• Inter-relay communications interfaces, RS422, G.703, IEEE C37.94
• Direct I/O - Exchange inputs and outputs between relays with reduced wiring
• Modbus RTU and TCP/IP
• IEC61850
• DNP 3.0 RTU and TCP/IP
• IEC60870-5-104
• Ethernet Global Data (EGD)

• 2 x 20 character front panel display and keypad for local access
• 48 programmable LED indicators
• User-programmable pushbuttons providing local control
• Multi-language support - French, Chinese, Russian options
• EnerVista™ UR Setup software for configuration, monitoring and troubleshooting

• Remote and Local Setting and Control passwords
• Configurable lockout responses to unsuccessful password access attempts
• Successful password access logged in Event Record