Transmission Protection

Multilin L90

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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

  • 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

  • CyberSentry™ provides high-end cyber security aligned to industry standards and services (NERC CIP, AAA, Radius, RBAC, Syslog)

  • AAdvanced IEC 61850 Ed. 1 and Ed. 2 certified implementation, complete settings via SCL files and flexible process bus support (IEC 61850-9-2LE 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

  • 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)

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