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Multilin L90
Line Current Differential System
Line protection system with segregated line current differential and complete distance protection

The L90 provides high-speed current differential protection suitable for transmission lines and cables of various voltage levels, while supporting complete distance protection and dual-breaker applications suitable for single and three-pole tripping applications. The L90 uses synchronized sampling at each relay to limit the impact of communications channel issues. The differential element's adaptive restraint balances sensitivity for internal faults and security during external faults. The L90 supports inter-relay protection communications via direct fiber as well as different interfaces.

Key Benefits
  • Phase-segregated differential protection ensures secure high-speed single-pole tripping
  • High-speed cost-effective five zones quad or mho, phase and ground distance protection with multiple standard and customizable pilot schemes support
  • Reliable and secure protection on lines equipped with series compensation
  • In-zone power transformer enables savings on CTs and protection device requirements
  • Increased sensitivity through dynamic charging current compensation and communication channel asymmetry compensation
  • Phasor Measurement Unit (synchrophasor) according to IEEE C37.118 (2011) and IEC 61850-90-5 support
  • Three independent fiber or copper Ethernet ports for simultaneous/dedicated network connections with 1 microsecond time synchronization via LAN with IEEE 1588 support
  • Advanced fault and disturbance recording, including internal relay operating signals, eliminating the need for external recording devices
  • CyberSentry™ provides high-end cyber security aligned to industry standards and services (NERC CIP, AAA, Radius, RBAC, Syslog)
  • Advanced IEC61850 Ed. 2 implementation, complete settings via SCL files and IEC 61850-9-2 process bus solution enable resource and platform managing optimization and reduce cost of ownership
  • Supports English, French, Russian, Chinese, Turkish and German languages on the front panel, software and manuals
  • Overhead lines including series-compensated lines and underground cables of different voltage levels
  • Circuits with tapped transformer feeders
  • Suitable for three-terminal line configurations, with channel redundancy and direct transfer tripping (DTT)
  • Wide area system monitoring and control and using integrated protection and synchrophasor measurement
  • Single and dual-breaker circuits requiring single/three-pole autoreclosing and independent synchrocheck supervision
  • Secure application with Capacitively-Coupled Voltage Transformers (CCVTs)

  Key Features    
  • Phase-segregated line current differential with adaptive restraint and ground differential, stub bus protection
  • In-zone power transformer enables savings on CTs and protection device requirements
  • Thermal protection, under/over frequency, broken conductor
  • Phase distance (five zones) with independent compensation settings for in-zone power transformers
  • Ground distance (five zones) with independent self and mutual zero- sequence compensation, reverse power
  • Line pickup, reverse power, out-of-step tripping and power swing blocking
  • Thermal overload, phase, neutral and negative sequence directional overcurrent; and broken conductor
  • Over, under and rate of change of frequency, synchronism check for dual-breaker applications
  •   Protection & Control
      The L90 is a high-end cost-effective line current differential protection relay intended for transmission lines and cables of different voltage levels, providing reliable and secure operation even under worst case power system conditions. The L90 provides high-speed phase-segregated fault clearance suitable for single and three-pole tripping applications. Part of the Universal Relay family, the L90 comes with a variety of versatile features, truly integrating protection, monitoring, metering, communication and control in one easy-to-use device. The Universal Relay family offers a high degree of modularity in its design and functionality, providing superior performance in protection and control, while meeting the toughest requirements of the marketplace.
    L90 Block Diagram
      Key Features    
  • Real-time monitoring of remote, local and differential per-phase currents
  • Oscillography - 64 samples/cycle, up to 64 records
  • Event Recorder - 1024 time tagged events, with 0.5ms scan of digital inputs
  • Data Logger - Up to 16 channels with user selectable sampling rate
  • P & M class synchrophasors of voltage, current and sequence components - 1 to 120 frames/sec
  • Multi-ended fault location consistently providing 2% accuracy
    The L90 is the single point for protection, control, metering, and monitoring in one integrated device that can easily be connected directly into DCS or SCADA monitoring and control systems like Viewpoint Monitoring as shown.
    The L90 incorporates advanced automation features including powerful FlexLogic™ programmable logic, communication, and SCADA capabilities that far surpass what is found in the average line relay. The L90 integrates seamlessly with other UR relays for complete system protection.
    FlexLogic allows for the customization of the L90 to operate and control the breakers and other auxiliary devices needed to fit most line protection schemes and applications.
      Key Features
  • Complete IEC 61850 Process Bus solution providing resource optimization and minimizing total P & C life cycle costs
  • Three independent 100Mbps Ethernet ports enable purpose specific LAN support that eliminates latency effect of heavy traffic protocols on mission critical communication services
  • Embedded IEEE 1588 time synch protocol support eliminates dedicated IRIG-B wiring requirements for IEDs
  • Direct I/O secures high-speed exchange of binary data between URs
  • Increase network availability by reducing failover time to zero through IEC62439-3 “PRP” support
    The L90 provides for secure remote data and engineering access, making it easy and flexible to use and integrate into new and existing infrastructures. Fiber optic Ethernet provides high-bandwidth communications allowing for low-latency controls and high-speed file transfers of relay fault and event record information. The available three independent and redundant Ethernet options provide the means to create fault tolerant communication architectures in an easy, cost-effective manner.
    The L90 supports the most popular industry standard protocols enabling easy, direct integration into monitoring and SCADA systems.
    • IEC 61850 Ed. 2 with 61850-9-2 (Process Bus) and 61850-90-5 (synchrophasors) support
    • DNP 3.0 (serial & TCP/IP)
    • IEC 60870-5-103 and IEC 60870-5-104
    • Modbus RTU, Modbus TCP/IP
    • HTTP, TFTP, SFTP and MMS file transfer
    • SNTP and IEEE 1588 for time synchronization
    • PRP as per IEC 62439-3
    • IRC module that combines C37.92 multimode and direct connection singlemode
    In addition to providing high-speed connectivity directly to your Universal Relay, the UR Switch Module provides an additional 4 fiber Ethernet ports, for connection to other relays in the system as well as upstream connectivity. It also provides 2 RJ45 copper Ethernet ports which can be used to connect local devices such as PCs, meters, or virtually anything else in the system.

    The UR Switch Module provides a simple way to add fully-managed Ethernet networking to your relays and devices without the need for additional hardware or a dedicated communications cabinet.

    The UR Switch Module includes all of the management and features that come with all MultiLink managed switches, and can be easily integrated into a network that has other Ethernet switches.

    When used in a ring topology with other UR Switch Modules or MultiLink Switches, the UR Switch Module can be configured to use MultiLink’s Smart RSTP feature to provide industry-leading network recovery for ring topologies, at a speed of less than 5ms per switch. Learn More

    Use the L90 with integrated IEC 61850 to lower costs associated with generator protection, control and automation. GE’s leadership in
    IEC 61850 comes from thousands of installed devices and follows on years of development experience with UCA 2.0.
      The L90’s IEC 61850 Process Bus module is designed to interface with the Multilin HardFiber System, allowing bi-directional IEC 61850 fiber optic communications. The HardFiber System is designed to integrate seamlessly with existing Universal Relay applications, including protection functions, FlexLogic, metering and communications. Learn More
    CyberSentry enables UR devices to deliver full cyber security features that help customers to comply with NERC CIP and NITIR 7628 cyber security requirements through supporting the following core features:

    Password Complexity
    Supporting up to 20 alpha- numeric or special characters, UR passwords exceed NERC CIP requirements for password complexity. Individual passwords per role are available.

    AAA Server Support (Radius)
    Enables integration with centrally managed authentication and accounting of all user activities and uses modern industry best practices and standards that meet and exceed NERC CIP requirements for authentication and password management.

    Role Based Access Control (RBAC)
    Efficiently administrate users and roles within UR devices. The new and advanced access functions allow users to configure up to five roles for up to eight configurable users with independent passwords. The standard “Remote Authentication Dial In User Service” (Radius) is used for authentication.

    Event Recorder (Syslog for SEM)
    Capture all cyber security related events within a SOE element (login, logout, invalid password attempts, remote/local access, user in session, settings change, FW update, etc), and then serve and classify data by security level using standard Syslog data format. This enables UR devices integration with established SEM (Security Event Management) systems.

    The EnerVista™ suite is an industry-leading set of software programs that simplifies every aspect of using the L90 relay. The EnerVista™ suite provides all the tools to monitor the status of the protected asset, maintain the relay, and integrate information measured by the L90 into DCS or SCADA monitoring systems. Convenient COMTRADE and Sequence of Events viewers are an integral part of the UR setup software included with every UR relay, to carry out postmortem event analysis and ensure proper protection system operation. Learn More
    New and Enhanced Communication Capabilities
    - IEC 61850 in line with Edition 2, IEC 61850 SCL file for all relay's setting (FW 7.30)
    - Three independent Ethernet ports (FW v7.00)
    - Time synchronization via IEEE 1588 (FW v7.00)
    - PRP as per IEC 62439-3 (FW 7.10)
    - IEC 60870-5-103 (FW v7.20)
    - New IRC module that combines C37.92 multimode and direct connection singlemode (FW v7.20)
    Cyber Security - CyberSentry UR (FW v7.xx)
    CyberSentry enables UR devices to deliver full cyber security features that help customers to comply with NERC CIP and NITIR 7628 cyber security requirements through supporting the following core features:
    - Password Complexity
    - AAA Server Support (Radius)
    - Role Based Access Control (RBAC)
    - Event Recorder (Syslog for SEM)

    Fully Compatible with GE's Multlilin HardFiber System - Provides support for GE's IEC 61850 HardFiber Process Bus Solution:
    - Complete IEC 61850 Process Bus Solution providing resource optimization and minimizing total P&C life cycle costs
    Learn More

    Extended Oscillography Records (FW v7.xx)
    - Configurable events allow for records of up to 45s at 64 samples per cycle
    New and Enhanced Protection and Control Functionality (FW version 5.90)
    - Remote voltage phasors enable synchrocheck with remote terminals
    - Added backup protection functions with sensitive reverse power element "32S"
    - Added over/under/rate of change of frequency elements
    - New thermal overload element
    - New broken conductor element
    - Customizable version of the POTT and DCB schemes "POTT1 and DCB1" (FW v7.20)
    - Neutral directional overcurrent with dual polarity criteria "67N" (FW v 7.20)