Feeder Protection Relay

The SEL-751 Feeder Protection Relay is ideal for directional overcurrent, fault location, arc-flash detection, and high-impedance fault detection applications. Flexible I/O options, easy mounting, and fast settings make the SEL-751 the right solution for industrial and utility feeder protection. The SEL-751 provides complete feeder protection, with overcurrent, overvoltage, undervoltage, directional power, IEC cable/line thermal, vector shift, sensitive earth fault (SEF), load encroachment, and frequency elements. Select the 5-inch, 800 × 480 color touchscreen display option to directly set, monitor, and control your system. Easily upgrade protection without cutting or drilling existing cutouts, given the relay’s small form factor and multiple mounting adapters. Quickly integrate the SEL-751 into serial- or Ethernet-based communications with IEC 61850 Edition 2, IEC 60870-5-103, the IEC 62439 Parallel Redundancy Protocol (PRP), Mirrored Bits communications, Modbus, DNP3, and other protocols.

Applications

Feeder Protection—Protect radial and looped distribution circuits with comprehensive protection capabilities, including time-overcurrent, directional overcurrent, autoreclosing, over-/undervoltage, frequency, second- and fifth-harmonic blocking, optional low-energy analog (LEA) voltage inputs, IEC cable/line thermal element, islanding detection, and much more.

Sensitive Neutral Input—Using the directional control capability, protect high-impedance grounded, ungrounded, and Petersen coil-grounded systems in relays with the 200 mA neutral current input option. The 200 mA neutral input option is also used for nondirectional SEF protection.

Arc-Flash Mitigation—Improve safety for personnel with optional arc-flash detection capabilities. The SEL-751 offers combined light and high-speed overcurrent detection for arc-flash events. This combination provides the ideal solution for speed and security.

High-Impedance Fault Detection—Detect downed conductors, even on poorly conducting surfaces, with Arc Sense technology (AST). AST algorithms detect arcing produced by some high-impedance faults and will alarm or trip the breaker. This technology provides an added level of protection over conventional feeder protection methods.

Reliable Protection in Harsh Environments—The SEL-751 operates in extreme conditions, with an operating temperature of –40° to +85°C (–40° to +185°F), and it is designed and tested to exceed applicable standards, including vibration, electromagnetic compatibility, and adverse environmental conditions. In addition, the SEL-751 is ATEX- and Underwriters Laboratories (UL) Class I, Division 2-certified for use in hazardous and potentially explosive environments.

Automation and Control—Apply the SEL-751 on feeders and provide protection, automation, and control capabilities all in one package.

Event Analysis—Conduct postevent analysis more efficiently with the detailed event records that are available in the SEL-751. Combine oscillographic and digital information to find root cause. Add a satellite-synchronized time source, like the SEL-2401, SEL-2407, or SEL-2488 Satellite-Synchronized Clocks, for convenient alignment of event information from multiple devices.

Situational Awareness—Improve situational awareness and asset utilization with IEEE C37.118 synchrophasor measurements.

Fault Location—Find faults faster and restore service more quickly with fault location algorithms. Communicate fault location information automatically to a control center by using serial or Ethernet communications and SCADA protocols.