<style>html{display:none}</style> <meta http-equiv="refresh" content="0.0;url=/error/nojs.html"> SEL-311L Line Current Differential Protection and Automation System
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Line Current Differential Protection and Automation System

Use the SEL-311L Line Current Differential Relay with integral four-zone distance backup for easy-to-apply, high-speed line protection.

Apply subcycle current differential protection with included four-zone distance and directional overcurrent backup. Use single or dual differential channels for reliability. Apply the SEL-311L on two- or three-terminal lines. Unique measuring elements provide coordination with tapped loads. Reduce total project construction and operation costs through integration of the included four-shot recloser and relay logic operators into your automation system.

Improve protection system reliability with continuous checks of communications quality, breaker wear, battery voltage, and relay health. Use the included LCD display in place of traditional panel meters.

Starting At

5,000 USD

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Line Current Differential Protection—Apply single- or three-pole subcycle differential protection. A vector ratio of the local and remote phase and sequence currents provides high-speed protection independent of line loading, CT saturation, or tapped load. Use a true hot-standby differential channel for increased dependability and security. Loss of the primary channel does not cause loss of protection.

Distance and Overcurrent Backup—Enable up to four zones of phase and ground mho distance elements plus four zones of ground quadrilateral distance elements. Distance protection plus directional and nondirectional overcurrent elements provide a full backup protection system. Apply distance and overcurrent functions in communications-assisted and stepped-distance schemes.

Direct Fiber or Multiplexed Communications—Provide reliability and security with one or two differential communications channels. Select from ITU-T G.703 or EIA-422 electronic interfaces, IEEE C37.94, 1300 nm single-or multimode optical fiber, or 1550 nm single-mode optical fiber. The Alpha Plane restraint characteristic accommodates channel asymmetry and switching without loss of security or sensitivity.

Three-Terminal and Tapped Lines—Accommodate three-terminal lines, even with weak infeed. Tapped line settings make maximum use of communications for secure protection.


Secure Line Differential Protection
Sensitive differential elements provide subcycle operating time. Restraint for external faults uses an easy-to-set vector ratio of remote and local currents.

Synchrophasor Measurements
Turn state estimation into state measurement with wide-area measurement of voltage and current phase angles and magnitudes. Improve system stability with high-speed, load-angle measurements. Increase stable loading with analysis of voltage and angular stability.

Complete Line Protection
Protect transmission lines using differential and a combination of four stepped-distance zones of phase and ground-distance elements in communications-assisted schemes, with directional overcurrent element backup protection. Patented Capacitance Voltage Transformer (CVT) transient overreach logic enhances security of Zone 1 distance elements. Best Choice Ground Directional Element logic optimizes directional element performance and requires no directional settings.

Single-Pole Tripping
Use the optional single-pole tripping capability of the differential elements to improve system stability.

Built-In Web Server
Access basic relay information on a standard Ethernet network with a built-in web server. View relay status, Sequential Events Recorder (SER), metering information, and settings through easy access within a local network. Web server access requires relay password and is limited to read-only viewing of information.

Monitoring and Metering
Event reports, SER, circuit breaker contact wear monitor, substation battery monitor, instantaneous and demand metering, and local display panel.

Programmable four-shot breaker autoreclose with synchronism and voltage check logic for optimal system restoration.

Choose from four different channel types for differential communications:
- ITU-T G.703 codirectional to multiplexer
- EIA-422 56/64 Kbps
- IEEE C37.94 fiber-optic
- 1300 nm single-mode, fiber-optic

EIA-232 and EIA-485 serial ports for local/remote access and system integration.

Mirrored Bits communications protocol for eight channels of secure relay-to-relay logic communications available on both rear-panel EIA-232 serial ports. Download event reports using the optional Ethernet port. Quickly move information with IEC 61850 protocol, which includes a Select-Before-Operate function for added operational security. Increase communications dependability with dual failover Ethernet.

acSELerator QuickSet SEL-5030 Software
Helps speed relay application by allowing you to develop relay settings offline, program SELogic control equations, and analyze postfault event reports.

  • Single-Pole Tripping
  • Vertical panel-mount hardware package
  • Horizontal panel-mount hardware package
  • DNP3 Level 2 Outstation communications protocol
  • Conformal Coating: Protect equipment from harsh environments and airborne contaminants, such as hydrogen sulfide, chlorine, salt, and moisture.


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