Sel 411L - Figure 3.222 Various Overcurrent Elements Used in this Example

P.3.339
Date Code 20151029 Protection Manual SEL-411L Relay
Protection Functions
Protection Application Examples
87PCT2:= 15 Second Harmonic Percentage (OFF, 5–100%)
87PCT4:= 15 Fourth Harmonic Percentage (OFF, 5–100%)
87PCT5:= 35 Fifth Harmonic Percentage (OFF, 5–100%)
87 Line Charging Current Compensation
Line-charging current compensation occurs at terminals S and R only.
Choose L for line side.
87CCLPT := L Location of PT Used for Charging Current Comp. (B, L)
87CCN := 2 No. of Line Term. Using Current Comp. ([range])
We would have the following at Relays S and R:
87CCB0 := 26.90 Zero.-Seq. Line Susceptance (0.00–100 mS, sec)
87CCB1 := 16.56 Pos.-Seq. Line Susceptance (0.00–250 mS, sec)
Instantaneous/Definite-Time Overcurrent Elements
Figure 3.222 shows the various overcurrent elements used in this example.
Figure 3.222 Various Overcurrent Elements Used in this Example
Set the overcurrent elements to pick up for appropriate values. Perform a
study if necessary to ensure coordination with downstream protections.
Set the pickup values at 50 percent of the fault current for a close-in internal
fault.
We would have the following at Relay S:
Pickup: 1/2 • (V
LN
/ [ • CTRS])
= 1/2 • (199.19 kV / [24  • 200])
= 20.7 A
50P1P := 20.7 Level 1 Pickup (OFF, 0.25–100 A, sec)
IAX
IW
BK1
IW
S
R
BK1
VY
VY
C
A
B
c
b a
BK1
IW
T
50P
1
51O
01
51O
01
50P
01
5OG
1
5OP
1
51O
01
411L-1
411L-3
411L-2
Z1S