Making Electric Power Safer, More Reliable, and More Economical ®

The SEL-351A provides comprehensive distribution and overcurrent protection for control and monitoring in a compact, secure, and economical package.

SEL-351A Protection System

Complete Overcurrent ProtectionProtect lines and equipment using phase, negative-sequence, residual-ground, and neutral-ground overcurrent elements with directional control.

Increased Overcurrent Element Security With Second-Harmonic Blocking

Use the second-harmonic blocking elements to detect transformer energization, and block selected tripping elements until inrush conditions subside.

Enhanced Breaker MonitoringInspect reports for the most recent operation, or gather trending data for up to 128 previous operations. This information allows timely and economical scheduling of breaker maintenance.

Rate-of-Change-of-Frequency ProtectionImprove frequency control with four independent rate-of-change-of-frequency (ROCOF) elements. Each element includes logic to detect either increasing or decreasing frequency, allowing control or switching action, such as network decoupling or load shedding.

Features and Benefits

—40°C +85°C

2

Optional front-panel USB port simplifies local connections and speeds relay communications.

Default displays, or programmable custom messages.

High-current interrupting output contacts.

Optional independent SafeLock® trip/close pushbuttons with high-visibility indication.

Standard multisession Modbus® TCP and DNP3. Optional IEC 61850.

Built-in phasor measurement unit.

Independent terminals forSafeLock trip/close pushbuttons.

®

Standard single copper Ethernet. Optional dual copper or fiber-optic Ethernet with fiber-optic serial port. Optional one copper, one fiber-optic Ethernet with fiber-optic serial port.

Optional sensitive earth fault (SEF) protection.

Functional Overview

Feature Overview

Harmonic metering to the 16th harmonic.

Optional EIA-485 port.

3

Use the SEL-351A synchronism check and voltage condition logic to program up to four shots of automatic reclosing with automatic or manual supervision.Sequence coordination logic is built in to synchronize relay protection to downstream recloser operations.

Instantaneous and Time-Overcurrent Elements• Use multiple instantaneous and time-overcurrent elements

with SELogic® control equations to coordinate protection with downstream devices. Best Choice Ground Directional Element® logic optimizes directional element performance and eliminates the need for many directional settings.

• Select from six phase, six negative-sequence, and six ground instantaneous overcurrent elements to best fit your application.

• Replace traditional latching relays and panel control switches with 16 internal logic latch control switches and up to 16 control switch functions.

• Eliminate RTU-to-relay wiring using serial or LAN/WAN communications to control up to 32 remote control switches.

• Use 16 programmable rotating messages on the front-panel LCD display to define custom messages.

Overcurrent Features

Advanced Reclosing Capabilities and Sequence Coordination

Advanced Automation

Fast Curve(Line Recloser)

51P Pickup

Slow Curve(Line Recloser)

t

IF I

51PT(SEL-351A)

51AT, 51BT, 51CT(SEL-351A)

SEL-351A

R

Line Recloser

IF

Fast Curve(Line Recloser)

51P Pickup

Slow Curve(Line Recloser)

t

IF I

51PT(SEL-351A)

51AT, 51BT, 51CT(SEL-351A)

SEL-351A

R

Line Recloser

IF

Sequence coordination between the SEL-351A and a line recloser.

Digitally Signed Firmware Upgrades• The cryptographically secure signature ensures that the file has been

provided by SEL and that its contents have not been altered.• If the SEL-351A cannot verify the signature, it rejects the corrupted or

altered firmware file.

Design Template Storage• Store any number of files inside one compressed file up to 750 kilobytes,

including acSELErator QuickSet® SEL-5030 Software settings files, an acSELErator QuickSet relay database containing a design template, or other files of your choice.

• QuickSet automatically verifies that settings match the design template upon retrieving the template from the relay.

Ease of Use and Security Benefits

acSELErator QuickSet Design template.

4

Load-encroachment logic allows you to set phase overcurrent elements below peak load current to see end-of-line phase faults on heavily loaded feeder applications. When the measured positive-sequence load impedance is in a region defined by the load-encroachment logic settings, this logic blocks the phase overcurrent elements. When a phase fault occurs, the positive-sequence load impedance measured indicates a fault condition and allows the phase overcurrent elements to operate.

Increased Security With Load Encroachment

SEL-351A and SEL-351A-1 Comparison

Features SEL-351A SEL-351A-1

SELogic Control Equations • •

IEC 61850 • •

Breaker Monitoring • •

Second-Harmonic Blocking •

Station Battery Monitor •

Synchronism Check •

Load-Encroachment Logic •

Rate-of-Change of Frequency (ROCOF) • •

Number of Frequency Elements 6 3

Directional Elements •

Web Server • •

Synchrophasors • •

acSELErator QuickSet Compatible • •

X1

Line Angle

Fault

52Line

3-Phase Fault

Load-OutRegion

SEL-351A

*

Maximum Load-OutMinimum LoadImpedance (Z1)

Positive-SequenceImpedance Plane

Load-InRegion

Underfrequency ProtectionApply six steps of underfrequency elements for multilevel under- and overfrequency trip and control and to provide comprehensive load control.

Rate-of-Change-of-Frequency (ROCOF) ProtectionImprove frequency control with four independent ROCOF elements. Each element includes logic to detect either increasing or decreasing frequency, allowing for control or switching action such as network decoupling or load shedding.

Flexible Underfrequency Elements

+−

+−

+−

TREND = INCREASING

TREND = DECREASING

ROCOF

TREND = ABSOLUTE

MEASUREDRATE-OF-CHANGE OF FREQUENCY

PICKUP SETTING

ROCOF logic diagram.

5

Communications Media• 10/100BASE-T Ethernet• 100BASE-FX Ethernet• EIA-232 Serial• EIA-485 Serial• USB Type B• BNC• Fiber-Optic MM ST Serial Port

Communications Protocols• IEEE C37.118 Synchrophasors• IEC 61850 GOOSE• IEC 61850 MMS• Modbus TCP• Modbus RTU• Telnet• DNP3 Serial• DNP3 IP• Web Server• SNTP• FTP• SEL Fast Messages• ASCII• IRIG-B

• Connect the SEL-351A directly to a local network with the built-in Ethernet interface or through an SEL-3530 Real-Time Automation Controller (RTAC).

• Use DNP3 LAN/WAN, Modbus® TCP and IEC 61850 to quickly send information through your networks.

• Increase communications reliability with separate and redundant communications ports.

• Transfer data at high speeds (10 Mbps or 100 Mbps) for fast HMI updates and file uploads.

• Use popular Telnet applications for easy terminal communication with SEL relays and other devices.

• Use popular FTP applications for easy transfer of settings, events, and history files.

• Transmit synchrophasor data to multiple clients using UDP and TCP formats.

• Simplify wiring and installation by receiving a time signal over existing Ethernet networks using Simple Network Time Protocol (SNTP). SNTP makes a good backup to more accurate IRIG-B time synchronization.

Integrate With Ethernet Networks

Flexible Communications

SEL-351S

SEL-487B

Wide-AreaNetwork

SEL-3354

SEL-2730M

SEL-3530

SEL-351AA

SEL-351A

A

A

SEL offers complete Ethernet direct-connect solutions.

The SEL-351A Relay offers many communications options.

Front Panel. Rear Panel.

6

SELogic control equations permit custom programming for traditional and unique protection and control functions. Add these programmable control functions to your protection and automation systems.

Access basic SEL-351A information on a standard Ethernet network with the built-in web server. View relay status, Sequential Events Recorder (SER) data, metering information, and settings through easy access within a local network. Web server access requires a relay password and is limited to read-only viewing of information.

Web Server

Specify optional SafeLock® trip/close pushbuttons and indicating lamps for your next SEL-351A application. The independently operated switches and breaker status lamps are functional even if the relay is out of service. Switch contacts and indicating lamps are separately wired to screw-terminal blocks on the rear of the relay. Choose the wiring arrangement that best suits your need for breaker control and status indication. The trip/close pushbuttons are equipped with the SafeLock system to prevent inadvertent operation and facilitate tagout procedures.

52a

52b52TC

43

local Remote Trip/Protection Trips

TRIP(manual/local)

BREAKERCLOSED

+

BREAKEROPEN

CLOSE(manual/local)

43

local

+

Remote Close/Autoreclose

To CloseCircuit

Optional trip/close pushbuttons operate independently from the relay function.

Eliminate Panel-Mounted Breaker Control Switches

Expanded SELogic Control Equations

Create your own custom applications using powerful SELogic control equations.

Operator Type Operators

Boolean +, *, !

Edge Detection /, \

Precedence Control ()

Web server menu screen.

7

Improve system performance with synchrophasor technology. SEL offers complete synchrophasor solutions, including hardware, communications, data collection, viewing and analysis software, and data archiving.

• Improve system performance using real-time system state measurement with time-synchronized voltages and currents available in the SEL-351A.

• Help system operators prevent cascading blackouts and monitor system stability with a new synchrophasor view of the power system.

• Use SEL-5078-2 SynchroWaVE® Central Software or third-party software to view and analyze system phase angles, load oscillations, voltage profiles, and other critical system information. Stream synchrophasor data with the IEEE C37.118 standard format.

Use acSELErator QuickSet SEL-5030 Software to set, monitor, and control the SEL-351A.

• Save engineering time while maintaining flexibility. Communicate with the SEL-351A through terminal software, or use the acSELErator QuickSet graphical user interface.

• Develop settings offline with a menu-driven interface and completely documented help screens. Speed installation by copying existing settings files and modifying application-specific items.

• Simplify the setting procedure with rules-based architecture to automatically check interrelated settings. Out-of-range or conflicting settings are highlighted for correction.

• Streamline configuration of IEC 61850 enabled relays with acSELErator Architect® SEL-5032 Software.

Easy-to-Use PC Software

Add Synchrophasors to Your System

acSELErator QuickSet settings form view.

acSELErator® event report.

Real-time SynchroWaVE Central data.

Pullman, Washington USATel: +1.509.332.1890 • Fax: +1.509.332.7990 • www.selinc.com • info@selinc.com

© 2009—2013 by Schweitzer Engineering Laboratories, Inc. PF00199 • 20130326

AC Current Inputs1 A or 5 A Inom (specify on order); 3 x Inom continuous; 100 x Inom one-second thermal rating; linear to 20 x Inom symmetrical

Burden 0.27 VA @ Inom for Inom = 5 A; 0.13 VA @ Inom for Inom = 1 A

AC Voltage Inputs300 VL-N continuous (connect any voltage up to 300 Vac) 600 Vac for 10 seconds

Burden 0.03 VA @ 67 V; 0.06 VA @ 120 V; 0.8 VA @ 300 V

Output Contact Ratings (standard model)30 A make per IEEE C37.90-1989; 6 A continuous carry @ +70˚C; MOV protected

Optional high-current interrupting (10 A @ L/R = 40 ms) contacts available

Serial Communications PortsOne front-panel and two rear EIA-232 serial ports, one optional rear-panel EIA-485 serial port, one optional fiber-optic serial port, and one optional front-panel USB port

SEL ASCII commands, SEL MirrorEd BitS communications, SEL Fast Messages, DNP3, Modbus RTU, and IEEE C37.118 synchrophasors

EIA-232 serial data speed: 300—57600 bps

Processing SpecificationsAC voltage and current inputs: 128 samples per cycle, 3 dB low-pass analog filter cut-off frequency of 3000 Hz

Digital filtering: Full-cycle cosine filters after low-pass analog and digital filtering

Protection and control processing: 4 times per power system cycle

Synchrophasors—IEEE C37.118 StandardUp to 50 messages per second (50 Hz system) Up to 60 messages per second (60 Hz system)

Power Supply24/48 V 18—60 Vdc 48/125 V 38—140 Vdc or 85—140 Vac 125/250 V 85—350 Vdc or 85—264 Vac

Ethernet Communications OptionsProvides IEC 61850, DNP3 LAN/WAN, FTP, Modbus TCP, SNTP, IEEE C37.118 synchrophasor, and Telnet protocols

Ethernet Connection Media Options: 10/100BASE-T twisted-pair network 100BASE-FX fiber-optic network

Frequency and Phase Rotation60/50 Hz system frequency and ABC/ACB phase rotation are user-settable

Operating Temperature—40˚ to +85˚C (—40˚ to +185˚F) Note: LCD contrast impaired for temperatures below —20˚C

Weight (maximum)11 lbs (5.0 kg)—2U rack-unit-height relay

General Specifications

SEL-351A Protection System