Project Description

SEL-387/SEL-387A Current Differential and Overcurrent Relay

SEL-387 Current Differential and Overcurrent Relay

The SEL-387 Current Differential and Overcurrent Relay provides protection, control, and metering for transformers, machines, buses, breakers, and feeders. Features include four three-phase current inputs with independent restrained and unrestrained differential protection, programmable single- or dual slope differential characteristic, circuit breaker monitor, battery voltage monitor, and enhanced SELOGIC® Control Equations.

Functional Overview

SEL-387 Functional Overview
SEL-387A Functional Overview
49 Thermal Monitoring
50 (P,G,Q) Overcurrent (Phase, Ground, Neg. Seq.)
51 (P,G,Q) Time-Overcurrent (Phase, Ground, Neg. Seq.)
87 Three-Phase Current Differential
87G Restricted Earth Fault (REF)
DFR Event Reports
ENV SEL-2600
LGC SELogic Control Equations
SER Sequential Events Recorder
BRM Breaker Wear Monitor
SBM Station Battery Monitor

* Optional

 

Front- and Rear-Panel Diagrams

SEL-387 Front Panel SEL-387 Rear Panel
Front Rear

 

Protection

Protect power transformers with as many as four windings using a combination of single- or dual-slope percentage differential characteristics, overcurrent protection, and Restricted Earth Fault (REF) protection.

Automation

Reduce total project costs through remote communications capa-bilities and elimination of external control switches and indicating lamps. Use remote communications capabilities for control, moni-toring, and alarm purposes.

Control

Locally control relay operation, and initiate or block automation sequences from remote sites or control systems.

Monitoring

Simplify fault and system disturbance analysis with event reports and sequential events recorder. Use breaker contact wear and substation battery voltage monitors to efficiently dispatch mainte-nance resources.

Specify optional thermal modeling per IEEE C57.91:1995 for mineral-oil immersed transformers. Use the thermal element to activate a control action or to issue an alarm when your transformer is in danger of excessive insulation aging or loss-of-life.

 

Comparison

487E 387E 387 387A 787 787-3E 787-3S 787-4X 587

APPLICATIONS

Breaker Failure Protection • f f f • • • • f
Transformer and Machine Current Differential • • • • • • • • •
Low-Impedance Bus Differential • • •
Underfrequency Load Shedding • f + • •
Undervoltage Load Shedding • f + • •
Three-Phase Current Inputs 5 3 4 2 2 3 3 4 2
Three-Phase Voltage Inputs 2 1 1+ 1 1

PROTECTION

24 Overexcitation (Volts/Hertz) • • + • •
25 Synchronism Check • •
27/59 Under-/Overvoltage • • + • •
32 Directional Power • + • •
46 Current Unbalance •
49 Equipment Thermal Monitoring • + • • • • •
50FO Flashover Protection f f f f f f
50 (N,G) Overcurrent (Neutral, Ground) • • • • • • • • •
50P Phase Overcurrent • • • • • • • • •
50Q Negative-Sequence Overcurrent • • • • • • • • •
51 (N,G) Time-Overcurrent (Neutral, Ground) • • • • • • • • •
51P Phase Time-Overcurrent • • • • • • • • •
51Q Negative-Sequence Time-Overcurrent • • • • • • • • •
67 (P,G,Q) Directional Overcurrent (Phase, Ground, Neg. Seq.) •
81 Under-/Overfrequency • • + • •
81R Change-in-Rate-of-Frequency f
87 Current Differential • • • • • • • • •
REF Restricted Earth Fault • • • + + • • •
SELogic Control Equations • • • • • • • • •
Voltage Check on Closing f f f •
Transformer Cooling Fan Control f f f f f
Nonvolatile Latch Control Switches • • • • • • • •
SELogic Remote Control Switches • • • • • • • • •
SELogic Local Control Switches • • • • • • • •
Display Points • • • • • • • •
Multiple Settings Groups • • • • • • • •
Substation Battery Monitor • • • • •
Breaker Wear Monitor • • • • • • •
Event Report (Multicycle Data) • • • • • • • • •
Sequential Events Recorder • • • • • • • •
Instantaneous Meter • • • • • • • • •
Demand Meter • • • • • • • • •
Load and Temperature Profile Report • • • • •
RTD (Resistance Temperature Detector) Inputs + + + +
Built-In Web Server • •
IEEE C37.118 Synchrophasors • • • • •
IEC 61850 + + + + + +
IEC 60870-5-103 + + +
Simple Network Time Protocol (SNTP) • • • • •
Parallel Redundancy Protocol (PRP) •
Through-Fault Monitor • • + • • • • •
2600 RTD Module Communications • • • • • • •
Thermal Model • +

MISCELLANEOUS FEATURES

Connectorized (Quick Disconnect) Available + + + + + + +
• Standard Feature
+ Model Option
f This function may be created using settings

Product Literature