SEL-387 Current Differential and Overcurrent Relay

Products for Protection, Monitoring, Control, Automation, and Metering

SEL-387

Current Differential and Overcurrent Relay

Use the SEL-387 Relay for protection, monitoring, and automation applications for important transformers, generators, and other power apparatus.

Two-, Three-, and Four-Winding Current Differential Protection
Sensitive current differential protection with programmable single- or dual-slope percentage restraint, supervised by a choice of second- and fourth-harmonic blocking or restraint elements, plus fifth-harmonic and dc blocking elements for secure protection of up to four windings. Phase current harmonic blocking is set for either common or independent winding basis. Unrestrained high-set differential elements provide fast operation for high-magnitude internal faults. "Around the clock" phase angle compensation settings and automatic tap calculations simplify settings.
Individual Winding Overcurrent Protection
Torque-controllable overcurrent elements, including one instantaneous, one definite-time, and one inverse-time element each for phase, negative-sequence, and residual ground currents, provide comprehensive overcurrent protection on each winding input. Combined current feature sums current from two CTs for ring-bus and breaker-and-a-half overcurrent applications.
Through-Fault Recording and Monitoring
Through-fault duty is recorded and accumulated for use in SELOGIC^® control equations or manual monitoring.
Protection and Control Logic
Restricted Earth Fault (REF) logic for sensitive grounded-wye winding ground fault protection. SELOGIC Control Equations with SELOGIC variables, timers, latch bits, and remote control elements for customizing advanced protection and control schemes. Local programmable control elements and programmable text display points for advanced local operator interface.
Metering and Reporting
Oscillographic event reports (up to seven 60-cycle reports), Sequential Events Recorder (SER) reporting, and accurate metering eliminate or reduce external recorder and metering requirements. Station battery voltage monitor and circuit breaker contact wear monitor provide important data for Reliability Centered Maintenance (RCM) programs.
ACSELERATOR^® QuickSet™ Software
Develop relay settings off-line, program SELOGIC control equations, and analyze post-fault event reports.

Thermal modeling element for key information about transformer overload capability.
Panel-mount or rack-mount hardware package.
Chassis available for one additional I/O board.
I/O board with contact sensing inputs and standard outputs, or high-current interrupting outputs.
Connectorized^® packaging (includes additional I/O inputs and output contacts).
Additional local and remote control switches and binary SER messaging.
Distributed Network Protocol (DNP) 3 Level 2 Slave communications protocol available in SEL-387-5, -6 models.
Conformal Coating (available in SEL-387-0, -5, -6 models.)—Protect equipment from harsh environments and airborne contaminants such as hydrogen sulfide, chlorine, salt, and moisture.
Learn more about conformal coating.

Use the thermal element to activate a control or issue a warning or alarm when the transformer overheats or is in danger of excessive insulation aging or loss of life. Capture current, hourly or daily, data about your transformer using the thermal event report.
Apply one SEL-387 Relay to protect any two-, three-, or four-winding power transformer.
Perform predictive maintenance based on accumulated through-fault duty as compared to transformer capability as defined in ANSI Standard C57.109. Use recorded fault values or an alarm set point to initiate an evaluation of transformer maintenance needs.
Protect reactors, generators, large motors, and other multiterminal power apparatus.
Apply with any combination of delta- or wye-connected CT secondary circuits.
Use built-in winding overcurrent elements for backup protection.
Use SELOGIC Control Equations to create breaker failure logic.
Detect ground faults through delta-wye transformer banks, or provide sensitive phase-to-phase protection, independent of load current, with negative-sequence overcurrent element.
Use low-side overcurrent elements for backup distribution bus or feeder protection.
Use any one of up to six independent setting groups to quickly adapt the relay to different application scenarios.
Use SEL-5040 Power System Report Manager Software to automatically gather relay event reports on your PC and manage them with a database.
Use SEL-5010 Relay Assistant Software to manage your relay settings.
Use SEL-5601 Analytic Assistant Software to display oscillograms and vector diagrams to analyze event reports.

SEL provides options to help you efficiently and safely commission and test these relays.
	Streamline commissioning by using the SEL-4391 Data Courier™ to gather event reports and install enhancements.
	When access to the back of panels and cabinets is allowed, use a Connectorized^® version of this relay for fast installation and testing.
	Improve safety, save time, and reduce costs with SEL-4600 Series Test Blocks and Plugs. Use the SEL recommended standard block and plug configurations for SEL-387 relays.

Budgetary Retail, Quantity 1: $5,000
Fully Optioned Price: $6,280
(Prices displayed are for planning purposes and are subject to change. Contact your SEL sales representative today for a quote on configurations and quantities to meet your needs.)