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Home > Grid Automation > Protection Relays > Line Protection > L90

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Multilin L90
Line Current Differential System

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 phase & ground distance (5-zones) with independent compensation settings with multiple standard and customizable pilot schemes support
  • Reliable and secure protection on lines equipped with series compensation
  • 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
  • Advance Cyber security features “CyberSentryTM” that helps meet modern industry requirements
  • AAdvanced IEC 61850 Ed. 1 and Ed. 2 certified implementation, complete settings via SCL files and flexible process bus support (IEC 61850-9-2LE, IEC 61869 or IEC 61850-9-2 Hardfiber) ensures interoperability, device managing optimization and reduced cost of ownership
  • Routable GOOSE (R-GOOSE) enables GOOSE messages going beyond the substation, which enables wide area protection and control applications
  • Application flexibility with multiple I/O options including high density I/O, programmable logic, modularity, and specific customization
  • An integrated large, full color display, provides real-time visualization and control of the protected bay, via a bay mimic as well as annunciator functionality and graphical visualization of phasors

Applications

  • 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)
What's New
Protection & Control
Monitoring & Diagnostics
Communications
Software & Security
UR 1 integrated Platform across all 18 applications
Communications icon

New and Enhanced Communication Capabilities

  • New process bus module supports IEC 61869 sample values, PTP master capabilities and SV switching (FW 7.9x)
  • New UR process bus modules supporting IEC61850-9-2LE Merging Units and IEC61850-9-2 Hardfiber (FW 7.8x) Module Training available here
  • Support switchable IEC 61850 Ed. 1 and Ed. 2 and redundant SNTP (FW 7.7x)
  • New UR front panel with integrated 7” color, graphical display - providing operators with enhanced situational awareness (FW 7.6x)
  • High density I/O module supporting up to 120 inputs or up to 72 contact outputs – eliminating the need for additional discrete devices (FW 7.6x)
Cyber security icon

Cyber Security - CyberSentry UR (FW v7.xx)

CyberSentryTM enables UR devices to deliver full cyber security features that help customers to comply with cyber security requirements (NERC CIP, IEEE 1686, IEC 62443, etc):

  • Secured firmware upgrade: FW file includes hash code that enables authentication prior to being used for upgrading UR Relay (FW 7.9x)
HardFiber icon

Fully Compatible with IEC 61850-9-2LE or IEC61869 process bus schemes:

  • Can connect to up to 8 merging units over -9-2LE or 61869
  • Supports PRP, HSR, dual HSR and point-to-point process bus topology
  • Provides support for GE’s IEC 61850 HardFiber Process Bus Solution
Oscillography icon

Extended Oscillography Records (FW v7.xx)

  • Increased number of digital and analog channels (FW 7.90)
  • Supports IEEE C37.111-1999/2013, IEC 60255-24 Ed 2.0 COMTRADE 2013 standard (FW v7.40)
  • Configurable events allow for records of up to 45s at 64 samples per cycle
Protection & Control icon

New and Enhanced Protection and Control Functionality

  • 6-distance zones and sub-cycle performance SW options (FW 8.0)
  • New TGFD and Inrush detection elements (FW 8.0)
  • Expanded Bay Controller Capabilities – providing a one box solution (FW 7.6x)

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
    • Sub-cycle distance performance available
  • Line pickup, reverse power, out-of-step tripping and power swing blocking
  • Thermal overload, phase, neutral and negative sequence directional overcurrent, TGFD, broken conductor and more
  • 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.

Functional Block Diagram

L90 Block Diagram

ANSI® Device Numbers & Functions

Device Number Function
21G Ground Distance
21P Phase Distance
24 Synchronism Check
25 Synchrocheck
27P Phase Undervoltage
27X Auxiliary Undervoltage
32 Sensitive Directional Power
49 Thermal Overload
50BF Breaker Failure
50DD Current Disturbance Detector
50G Ground Instantaneous Overcurrent
50N Neutral Instantaneous Overcurrent
Device Number Function
50P Phase Instantaneous Overcurrent
50_2 Negative Sequence Instantaneous Overcurrent
51G Ground Time Overcurrent
51N Neutral Time Overcurrent
51P Phase Time Overcurrent
51_2 Negative Sequence Time Overcurrent
52 AC Circuit Breaker
59N Neutral Overvoltage
59P Phase Overvoltage
59X Auxiliary Overvoltage
Device Number Function
67_2 Negative Sequence Directional Overcurrent
67N Neutral Directional Overcurrent
67P Phase Directional Overcurrent
68 Power Swing Blocking
78 Out-of-Step Tripping
79 Automatic Recloser
81U/O Under/Over Frequency, df/dt
87L Segregated Line Current Differential
81ROCOF Rate of Change of Frequency
87LG Ground Line Current Differential

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

Monitoring & Diagnostics

Monitoring & Diagnostics

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.

Advanced Automation

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™ diagram

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, HSR or dual HSR support

Advanced Communications

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 61850-9-2LE/IEC 61869 networked or IEC61850-9-2 Hardfiber process bus 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
  • Redundant SNTP and IEEE 1588 for time synchronization
  • PRP as per IEC 62439-3
  • IRC module that combines C37.92 multimode and direct connection singlemode
  • Supports Routable GOOSE (R-GOOSE)

Interoperability with Embedded IEC 61850

Use the L90 with integrated IEC 61850 to lower costs associated with line differential 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.

HardFiber system

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

The L90 can also connect to GE MU320 or third-party merging units using standard IEC 61869 or IEC 61850-9-2LE communication protocols.

Cyber Security - CyberSentry™ UR (FW v7.4xx)

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:

Secure FW upgrade

UR FW files v7.9 and up now include a hash code that allows for authentication prior to being used for upgrading UR devices.

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.

EnerVista™ Software

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

Enervista Software