SEL-787L

Line Current Differential Relay

The SEL-787L is an economical and dependable line current differential protection solution for lines and feeders, providing conventional/low-energy analog (LEA) current and voltage input support, flexible I/O options, easy mounting, and fast settings.The SEL-787L also offers directional overcurrent protection, arc-flash mitigation, fault locating, high-impedance fault detection, broken-conductor detection, intermittent ground fault (IGF) detection, event analysis, and more—making it an effective choice for short lines, critical feeders, and distributed generation tie-ins.You can quickly integrate the relay into serial- or Ethernet-based communications with IEC 61850 Edition 2.1, IEC 60870-5-103, the IEC 62439 Parallel Redundancy Protocol (PRP), the High-Availability Seamless Redundancy (HSR) protocol, EtherNet/IP, the Rapid Spanning Tree Protocol (RSTP), the IEEE 1588 Precision Time Protocol (PTP), Modbus, DNP3, and other protocols.

Configure and order

Line Current Differential Protection

Apply differential protection in two-terminal applications using a serial fiber-optic communications port. The differential element operates on percentage-restrained characteristics with settable normal and secure mode slopes. Disturbance detection logic enables the 87L function to operate with exceptional security against undetected bit errors in communications packets. External fault detection logic provides security against CT saturation under heavy external fault conditions. Built-in charging current compensation improves the sensitivity of differential protection for long lines.

LEA Sensor Inputs

Apply the SEL-787L in applications that use low-energy current/voltage sensors. LEA sensors for measurement of primary voltages and currents offer excellent linearity, a wide dynamic range, reduced size and weight, and enhanced personnel safety. The LEA current/voltage input card supports three current channels that are either 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.

Arc-Flash Mitigation

Improve safety for personnel with optional arc-flash detection capabilities. The SEL-787L offers combined light detection 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 send an alarm or trip the breaker. This technology provides an added level of protection over conventional feeder protection methods.

Fault Locating

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

Flexible I/O Options

Order the SEL-787L with the I/O needed to support your application and allow for future expansion. The back of the relay features field-upgradable I/O cards; many options are available, including a card with 14 digital inputs. Provide ample I/O for automation and control applications by ordering up to four extended I/O modules with your relay; each module provides 21 programmable inputs or 12 contact outputs.

IGF and Zero-Sequence Phi Elements

Use the IGF detection and zero-sequence phi elements in resonant-grounded and ungrounded systems to identify ground faults and their direction. Set them to send a trip command if the count of faults exceeds a particular threshold.

Updates

Now available in the SEL-787L

New ordering option for up to four integrated I/O modules, each with 21 programmable inputs or 12 contact outputs

Zero-sequence phi and intermittent ground fault detection elements to support resonant grounding and ungrounded systems
Support for the High-availability Seamless Redundancy (HSR) protocol
Total harmonic distortion element and harmonic metering
Arc Sense technology (AST) enhancements for high-impedance fault (HIF) detection: selective tuning windows, new HIF armed status, and multiple sensitivity levels
Support for the Precision Time Protocol (PTP) over fixed, failover, and HSR networking modes

SEL-787L Features

Large 2 × 16 character LCD.
Default messages or up to 32 customizable display labels notify personnel of power system events or the relay status.
Programmable front-panel tricolor LEDs.
Customizable pushbuttons and labels.
User-configurable label kit.
Two programmable tricolor LEDs per pushbutton.

The 5-inch (12.7 cm), 800 × 480 display offers direct navigation via a capacitive touchscreen.
Folders and applications provide quick access to bay screens, metering and monitoring data, reports, settings, and more.
The programmable home pushbutton allows you to easily return to the default home screen or to a variety of meter, report, or monitor screens.
Programmable front-panel LEDs with user-configurable labels alert operators to faulted phases and element operation.
Programmable operator pushbuttons with user-configurable labels allow front-panel customization.
Add up to four optional extended I/O modules.

Optional output module provides 12 contact outputs.
Optional input module provides 21 programmable inputs.
Power supply options include 110–250 Vdc/110–240 Vac or 24–48 Vdc.
A variety of communications protocols provide flexibility to communicate with other devices and control systems.
The integrated web server enables direct relay access for metering and monitoring data.
Choose a single-mode or multimode fiber-optic port for IEEE C37.94-compliant 87L communications.
Card slots include positions for optional I/O or an arc-flash detection/Vsync/Vbat card.
Phase current and optional phase voltage inputs are on one card, freeing up space for additional SELect I/O card options.

Power supply options include 110–250 Vdc/110–240 Vac or 24–48 Vdc.
A variety of communications protocols and media provide flexibility to communicate with other devices and control systems.
The integrated web server enables direct relay access for metering and monitoring data.
Choose either fiber or copper connections for the IEEE C37.94-compliant 87L communications channel.
Card slots include positions for optional I/O or an arc-flash detection/Vsync/Vbat card.
LEA current and voltage sensor inputs (compliant with IEC 61869-10, -11 standards).

MKTGREN-214_787L_LDM_8PB_F_BayScreen1(1).jpg

Bay Screens and Bay ControlSelect from predefined bay screens, or configure as many as five custom bay screens using the acSELerator Bay Screen Builder SEL-5036 Software and acSELerator QuickSet SEL-5030 Software. You can monitor up to two breakers, eight two-position disconnects, and two three-position disconnects and can view analog and digital data in a contextual display. To control a breaker or disconnect, simply tap the Bay Screens application on the home screen and then select the breaker or disconnect you want to control.

SEL-787L Details

87L Channel Monitoring
To aid in commissioning and to help maintain security and dependability, the SEL-787L provides a set of channel monitoring and alarming functions.87L Communications Report
The SEL-787L provides an 87L communications report to visualize and summarize basic 87L configuration as well as real-time and historical channel monitoring and alarming values. The report includes 87L configuration information, diagnostics, channel health information, a channel delay histogram, and worst-case channel delay information.Directional Overcurrent Protection
Use overcurrent elements with directional control, and 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. The relay also supports high-impedance grounded, ungrounded, and Petersen coil-grounded systems in relays with the 200 mA neutral current transformer option. The 200 mA CT option can also be used for nondirectional sensitive earth fault (SEF) protection.Optional Protection Features
Use the SEL-787L with the voltage inputs and arc-flash detection options to provide synchronism check, dc station battery monitoring, and arc-flash detection. An optional expansion card includes Vsync/Vbat with seven digital inputs or four arc-flash inputs. The LEA current/voltage input card supports voltage sensor inputs as well as Rogowski coil or low-power current transformer (LPCT) inputs for small enclosure installations.Incipient Fault Detection
Identify potential cable failures to extend asset life and minimize unexpected downtime. The SEL-787L checks for self-extinguishing half-cycle faults, which provides an indication of imminent cable failures.Cold-Load Pickup Element
Cold-load pickup takes place when a distribution circuit is re-energized following an extended outage. It can result in current levels significantly higher than normal peak load levels. This excess amount of current draw could be falsely identified as an overcurrent condition by the relay. The cold-load pickup element identifies possible cold-load pickup events per the settings in a distribution line after an outage.Thermal Element
Protect cables and cable insulation against thermal damage using the IEC line/cable thermal (49) element.Optional Vector Shift
Detect islanding conditions and prevent damage to local generation by detecting voltage angle shifts upon loss of bulk generation.Open-Conductor DetectionApply the SEL-787L to detect and isolate open conductors. The SEL-787L incorporates phase discontinuity detection and optional broken-conductor detection to provide a reliable solution for open-conductor faults that convert to high-impedance faults.Optional Touchscreen Display
The easy-to-use touchscreen interface provides a one-line mimic display for bay control and monitoring. View metered quantities, phasor diagrams, relay settings, event summaries, target statuses, Sequential Events Recorder (SER) data, and more. Extensive testing shows that the robust capacitive touchscreen display meets or exceeds industry standards as well as SEL quality and reliability requirements. The touchscreen overlay can be configured in English or Spanish. Harmonic Metering and Total Harmonic Distortion (THD)
Harmonic metering and a THD element allow greater control and monitoring of systems that see significant harmonic disturbances, such as industrial systems and systems with inverter-based resources.Easy Communications
Choose from Ethernet or serial communications and several protocols, including IEC 60870-5-103, Mirrored Bits communications, EtherNet/IP, IEEE 1588 PTP, and IEC 61850 Edition 2.1. Pick multiple sessions of Modbus TCP, Modbus serial, DNP3 LAN/WAN, or DNP3 serial for custom configuration of your applications. When dual-Ethernet ports are selected, the relay also supports RSTP, IEC 62439-3 PRP, High-Availability Seamless Redundancy (HSR), and fast failover switching.IEC 61850 Edition 2.1 Communications Protocol
Combine IEC 61850, an Ethernet network, and the SEL-787L for the fastest overall performance for substation automation and control. Streamline configuration of IEC 61850-enabled relays with acSELerator Architect SEL-5032 Software. Improve security using the password authentication and session time-out features. Transfer event files in COMTRADE and CEV formats as well as CID files, settings, and reports.IEC 61850 Test Mode
Use the IEC 61850 Test Mode to test system components in energized substations without fear of operating control output contacts.Web Server Access
The built-in web server enables secure, remote access to the relay with password protection. You can download status reports or view metering and relay information remotely. This helps minimize trips to the relay location, saving time and money.Accelerate Firmware Downloads
Simplify maintenance by downloading relay firmware via the Ethernet port. This also enables you to access and update all of your network relays simultaneously.Simple Network Time Protocol (SNTP)
Simplify wiring and installation by receiving a time signal over existing Ethernet networks. The 5 ms accuracy of SNTP is ideal for basic time synchronization throughout a substation, and it is a good backup to more accurate IRIG-B time synchronization.Built-In IEEE C37.118 Synchrophasors
Monitor distribution networks to detect a potential cascading voltage collapse before it happens. IEEE C37.118 synchrophasors, at up to 60 messages per second, allow access to system values for wide-area monitoring and control. The IEEE C37.118 standard simplifies communication and data coordination between synchrophasor measurement units.Expanded SELogic Control Equations
Use math and logic combinations of analog and digital values for customized applications. Adapt system control based on pre-fault conditions. Scale analog values and latch momentary inputs for SCADA retrieval.Enhanced Security on Heavily Loaded Feeders
Employ load-encroachment logic to set phase overcurrent elements independently of load levels.Easy Installation
Easily install the SEL-787L into existing locations using available retrofit kits and mounting adapters, with no cutting or drilling. Choose from many installation and integration options given the relay’s small form factor and slide-in expansion card options. Rugged Design
Trust the industry’s widest ambient operating temperature range, –40° to +85°C (–40° to +185°F). The SEL-787L withstands vibration, electrical surges, fast transients, and extreme temperatures, meeting stringent industry standards. A conformal-coating option for the printed circuit boards provides an additional barrier to airborne contaminants, such as hydrogen sulfide, chlorine, salt, and moisture.

Directional Overcurrent Elements
Zero-Sequence Phi Directional Element
Pushbutton Options Available on Two-Line Display Model
Sensitive Ground Fault Protection and IGF Detection
High-Impedance Fault Detection Using AST
Flexible I/O for Local Control and System Applications
The base system includes three digital outputs (DO) and two digital inputs (DI). There are three card slots for optional SELect I/O cards, including the following:

4 current inputs and 3-phase voltage inputs (SELect 4 ACI/3 AVI)
LEA voltage sensor inputs, Rogowski coil/LPCT current inputs, and conventional 200 mA sensitive neutral input
2 ac voltage inputs (300 V Vsync or 8 V LEA Vsync and Vbat) and 4 arc-flash detection input (AFDI) sensor inputs
2 ac voltage inputs (300 V Vsync or 8 V LEA Vsync and Vbat) and 4 AFDI sensor inputs
8 AFDI sensor inputs
4 current inputs and 3-phase LEA voltage (8 Vrms) inputs for LEA voltage sensors
14 DI
4 DI and 4 DO
4 DI and 4 fast, high-current interrupting DO
4 DI and one Form B DO or 2 Form C DO
4 DO, 3 DI, and 1 analog output (AO)
4 analog inputs (AI) and 4 AO
8 AI for dc process values
8 DI
8 DO
10 RTE inputs
Add up to four extended I/O modules:

Input moduel—21 programmable inputs
Output module—12 contact outputs

Integrated Communications
The SEL-787L offers many communications media and protocol options. Versatile communications options provide fast integration into both new and existing applications.

Communications Media

Ethernet 10/100BASE-T
Ethernet 100BASE-FX
Single- or dual-Ethernet ports
EIA-232 serial
EIA-485 serial

87L Communications

Fiber-optic serial multimode ST
Fiber-optic serial single-mode ST

Communications Protocols

Mirrored Bits communications
IEC 61850 Edition 2
IEC 60870-5-103
IEC 62439-3 PRP, RSTP, and HSR for models with dual Ethernet
DNP3 LAN/WAN
DNP3 serial
Modbus TCP
Modbus RTU
Telnet
FTP
EtherNet/IP
IEEE 1588 PTP
IEEE C37.118 synchrophasors
Simple Network Time Protocol (SNTP)
Fixed GOOSE

Languages
An ordering option is available for English or Spanish language support.
Retrofit Replacement Kits
Replace existing feeder protection with the SEL-787L and the applicable mounting kits. These kits provide the parts needed to easily replace many older feeder relays with the SEL-787L. Find other mounting options with the SEL Mounting Selector.
Conformal Coating
Protect equipment from harsh environments and airborne contaminants, such as hydrogen sulfide, chlorine, salt, and moisture.
Projection Mounting Collars Available in 45 and 90 mm
Projection Mounting Collars Instruction Sheet
Find other mounting options with the SEL Mounting Selector.