The SEL-751 is the right solution for industrial and utility feeder protection, with conventional/low-energy analog (LEA) current and voltage input support, flexible I/O options, easy mounting, and fast settings. The SEL-751 provides complete protection for radial and looped distribution circuits. It offers arc-flash mitigation, fault location, high-impedance fault detection, broken conductor detection, event analysis, and more. You can quickly integrate the relay into serial- or Ethernet-based communications with IEC 61850 Edition 2, IEC 60870-5-103, the IEC 62439 Parallel Redundancy Protocol (PRP), EtherNet/IP, the Rapid Spanning Tree Protocol (RSTP), the IEEE 1588 Precision Time Protocol (PTP), Modbus, DNP3, and other protocols.
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.
LEA Sensor Inputs—Apply the SEL-751 in medium- and low-voltage applications that use low-energy current/voltage sensors. LEA sensors for measurement of primary voltages and currents are gaining popularity owing to their excellent linearity and wide dynamic range characteristics, reduced size, reduced weight, and enhancement of personnel safety. The LEA current/voltage input card supports three current channels, Rogowski coil or low-power current inputs, three LEA voltage sensor inputs, and one 200 mA neutral input. The LEA current and voltage channels accept an RJ45 connector input, and the 200 mA neutral channel accepts a terminal block input.
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-certified 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 post-event 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.