SEL SEL-751 Feeder Protection Relay

SEL-751 Feeder Protection Relay

Comprehensive Feeder Protection and

Control With Arc-Flash Detection

Added the option to add as many as 4 I/O modules, each with 21 programmable inputs or 12 electromechanical

outputs, during product configuration.

➤ Added intermittent ground fault detection for compensated networks using a Petersen coil.

➤ Added High-availability Seamless Redundancy (HSR) protocol.

➤ Added zero-sequence PHI directional elements for ungrounded, impedance-grounded, and Petersen coil-grounded

systems.

➤ Updated IEC 61850 protocol implementation to IEC 61850 Edition 2.1.

➤ Added THD elements and harmonic metering.

Major Features and Benefits

The SEL-751 Feeder Protection Relay provides a comprehensive combination of protection, fault-locating, monitoring,

control, and communication features in an industrial package.

➤ Standard Protection Features. Protect lines and equipment with an extensive range of protection elements,

including:

➢ Overcurrent elements

➢ Over- and underfrequency elements

➢ Second- and fifth-harmonic current blocking

(inrush blocking)

➢ Demand metering elements

➢ Breaker failure protection

➢ Phase discontinuity detection

➢ Cold-load pickup

➢ Incipient cable fault detection

➢ Frequency component detection

➢ Breaker failure protection

➢ SELOGIC® control equations

➢ Cable or line thermal elements that conform to

the IEC 60255-149 standard

➤ Additional Protection Features. Use the SEL-751 with one of the voltage input options to protect lines and

equipment with rate-of-change-of-frequency elements, fast rate-of-change-of-frequency elements, definite-time

and inverse-time over- and undervoltage elements, and load-encroachment and directional power elements. Also

take advantage of the vector shift elements to aid in islanding detection.

➤ Optional Directional Control. Use overcurrent elements with directional control to optimize radial and looped

network protection for lines and equipment. Best Choice Ground Directional Element® logic optimizes directional

element performance and eliminates the need for many directional settings.

➤ Optional High-Impedance Fault Detection. Use the high-impedance fault (HIF) detection element to detect

small-current ground faults that typically result from downed conductors on ground surfaces, such as earth,

reinforced concrete, or other poorly conductive materials. HIF event data are available in COMTRADE or

Compressed ASCII format.

➤ Optional Arc-Flash Protection. Reduce or eliminate damage from arc-flash events with the optional four- or

eight-channel fiber-optic arc-flash detector inputs and protection elements. Settable arc-flash phase and neutral

overcurrent elements, combined with arc-flash light detection elements, provide secure, reliable, and fast arc-flash

event protection.

➤ Optional Broken Conductor Detection. The broken conductor detection (BCD) element identifies high

impedance downed conductors when combined with the Arc Sense™ technology (AST) option on wye-connected

systems. This detector operates on three-phase and single-conductor systems and can help reduce the possibility of

a public hazard, including fire.

➤ Optional Low-Energy Analog (LEA) Voltage Sensor Inputs, Rogowski Coil/LPCT Currents Inputs, and

Conventional 200 mA Sensitive Neutral Input. The LEA input range for voltages is as high as 8 Vac rms. Based

on the nominal feeder current, the relay automatically sets the gain for the LEA current channel inputs, which

allows for a wide range of primary currents.

➤ Optional Synchronism Check and DC Station Battery Monitor. Check single-phase voltage across a circuit

breaker, measure dc voltage levels in the substation battery, or use as an additional ac voltage measurement with

over- and undervoltage elements.

➤ Operator Controls and Reclosing. Trip and close the breaker easily with four or eight programmable front-panel

pushbuttons, each with two tricolor LEDs. Implement remote and local control functions, and selectively reclose

with synchronism and voltage checks.

➤ Integrated Web Server. View settings and metering and monitoring data, download event reports, and upgrade

relay firmware with an intuitive password-protected web server.

➤ Relay and Logic Settings Software. Reduce engineering costs by using ACSELERATOR QuickSet® SEL-5030

Software for relay settings and logic programming and to simplify development of SELOGIC control equations.

➤ Metering and Monitoring. Use built-in metering functions to eliminate separately mounted metering devices.

Analyze Sequential Events Recorder (SER) reports and oscillographic event reports for rapid commissioning,

testing, and post-fault diagnostics. Unsolicited SER protocol allows station-wide collection of binary SER

messages.

➤ Optional Fault Location. Reduce fault location and repair time with built-in, impedance-based fault location and

faulted phase indication.

➤ Wye or Delta Voltage Inputs. Connect voltage inputs that are wye-connected, open-delta-connected, or single

voltage.

➤ Additional Standard Features. Improve your feeder protection with these additional standard features in every

SEL-751: Modbus RTU, Event Messenger support and MIRRORED BITS® communications, load profile and