1-2 Introduction and Specifications Date Code 20080110
SEL-387E Instruction Manual
Section 2: Installation to learn how to configure, install, and wire your relay.
Section 10: Testing and Troubleshooting for test procedures and a troubleshooting guide. You
can use this section as a tutorial to check your understanding of the relay's operation.
R
ELAY
F
UNCTIONS
52
52
52
24
V/Hz Under-/
Overfrequency
81
Undervoltage
27
Time Overcurrent
Phase
Ground
Neg. Seq.
Overcurrent
Phase
Ground
Neg. Seq.
Time Overcurrent
Phase
Ground
Neg. Seq.
Three-Phase
Current
Differential
Overcurrent
Phase
Ground
Neg. Seq.
Time Overcurrent
Phase
Ground
Neg. Seq.
Overcurrent
Phase
Ground
Neg. Seq.
Combined
Time Overcurrent
Phase
Ground
Overvoltage
59
50
P
G
Q
51
P
G
Q
50 87
P
G
Q
51
P
G
Q
50
P
G
Q
51
51
P
G
Q
SEL-387E Relay
P
G
Auto-
transformer
3
3
SELOGIC
®
Control Equations
Event Reports and
Sequential Events Recorder
Breaker Wear Monitor
Station Battery Monitor
ASCII, Binary, and Distributed
Port Switch Communications
Remote and Local
Control Switches
Accurate Metering
Restrained and Unrestrained
Differential Elements
Second- and Fifth-
Harmonic Blocking
CT and Transformer
Connection Compensation
*Additional I/O
*Optional Functions
3
Figure 1.1: SEL-387E Relay Functional Overview
Current Differential Protection
The SEL-387E Relay includes independent restrained and unrestrained current differential
elements. The restrained element has a dual-slope, variable-percentage restraint characteristic.
Use the fifth-harmonic element to prevent relay misoperation during allowable overexcitation
conditions. Even-harmonic elements (second and fourth harmonic) provide security against
inrush currents during transformer energization, complemented by the dc element which
measures the dc offset. The even-harmonic element offers the choice between harmonic
blocking and harmonic restraint. In the blocking mode, the user selects either blocking on an
individual phase basis or on a common basis, as per application and philosophy. The second-,
fourth-, and fifth-harmonic thresholds are set independently, and the dc blocking and harmonic
restraint features are enabled independently. A separate unrestrained differential element
provides faster clearance of high-magnitude internal faults.
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