SEL-851
Feeder Protection Relay
- The SEL-851 is a compact, simple, yet powerful protection relay designed for utility and industrial feeder protection. It integrates protection, monitoring, and control functions for low- and medium-voltage feeders into a single compact package. The relay features exceptional responsiveness, with protection becoming active within 2 seconds of power-up. It is optimized for quick and easy field application by minimizing setup complexity.
Key Features
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Ultra-Fast Arc-Flash Protection
Sends a trip signal to the breaker in as fast as 1 ms when using hybrid contacts, significantly reducing incident energy and protecting personnel and equipment. -
High-Precision System Visibility
Measures current and voltage at a high sampling rate of 10 kHz to provide precise data on the power system's state. -
Comprehensive Protection Suite
Equipped with various protection elements based on current, voltage, and frequency, supporting a wide range of ANSI functions including directional power (32), overcurrent (50/51), and under/overvoltage (27/59). -
Dual Ethernet Communications
Supports communication redundancy via dual Ethernet ports and ensures easy system integration through industry-standard protocols such as IEC 61850 Edition 2, DNP3, and Modbus TCP. -
Breaker Failure Detection and Control
Enhances system reliability by integrating breaker failure detection and auto-reclosing control functions.
Convenience features
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Universal Design
Simplifies hardware selection and inventory management by utilizing a universal power supply (24–250 Vdc / 110–240 Vac) along with software-configurable current and digital inputs. -
Front-Panel USB-C Port
Enables direct connection to a laptop for fast transfer of settings and diagnostic data without the need for a separate adapter or converter. -
SEL Grid Configurator Support
Reduces engineering time by allowing users to quickly create, manage, and deploy relay settings through an intuitive and modern software interface. -
Built-in Web Server
Features an internal web server (supporting HTTP/HTTPS) for easy access to real-time status, metering, and device information via a standard web browser. -
Compact Form Factor
The space-efficient design allows for easy mounting in tight spaces within switchgear, streamlining installation and wiring.
