Schweitzer Engineering SEL-387-0, Instruction Manual

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3.60
SEL-387-0, -5, -6 Relay Instruction Manual Date Code 20170601
Differential, Restricted Earth Fault, Thermal, and Overcurrent Elements
Overcurrent Element
Winding n Overcurrent Element and Demand Threshold Enables (EOCn)
Range: Y, N
Set EOC1 = Y to enable overcurrent elements and demand thresholds for
Winding 1. The operation is identical for the other three windings. The relay
default is for Winding 1–3 overcurrent elements and demand thresholds to be
enabled, while Winding 4 overcurrent elements and demand thresholds are
disabled (EOC4 = N).
Combined O/C Element Enable (EOCC)
Range: Y, N
Set EOCC = Y to enable combined overcurrent elements. A setting of
EOCC = N disables the elements.
Instantaneous and Definite-Time Element Pickups
(50PnmP, 50QnmP, 50NnmP)
Range: 1 A: OFF, (0.05–20), A secondary, in 0.01 A steps
5 A: OFF, (0.25–100), A secondary, in 0.01 A steps
Set pickups for the current level above which you want the elements to assert.
As the name of the instantaneous elements suggests, assertion occurs almost
immediately after current exceeds the threshold you specify. A definite-time
element asserts only after current exceeds the level you specify and after a
time delay that you specify with the definite-time delay setting.
Definite-Time Element Delays (50Pn1D, 50Qn1D, 50Nn1D)
Range: 0–16000 cycles, in 0.25-cycle steps
Select a time in cycles that you want definite-time elements to wait before
asserting.
Inverse-Time Element Pickups (51PnP, 51QnP, 51NnP, 51PCmP, 51NCmP)
Range: 1 A: OFF, (0.1–3.2), A secondary, in 0.01 A steps
5 A: OFF, (0.5–16), A secondary, in 0.01 A steps
The pickup setting acts as a horizontal scaling factor for an inverse-time curve,
because the curve formula uses current multiple of pickup as an input.
Set pickups, and the following three settings defining the time overcurrent
curve, to fit the practices of your organization, coordinate with upstream and
downstream devices such as fuses and motors, and accommodate transient and
fault conditions.
Curve Shape Settings (51PnC, 51QnC, 51NnC, 51PCmC, 51NCmC)
Range: U1, U2, U3, U4, U5
C1, C2, C3, C4, C5
This setting defines a particular curve equation for an inverse-time curve from
among five U.S. (U1–U5) and five IEC (C1–C5) curves.
NOTE:
n = Winding 1, 2, 3, or 4;
m = Level 1, 2, 3, or 4.
NOTE:
For combined winding
element settings, m = 1: W1 + W2;
m = 2: W3 + W4.
NOTE
: For combined winding
element settings, m = 1: W1 + W2;
m = 2: W3 + W4.