Schweitzer Engineering Laboratories SEL-311L, Instruction Manual, Page: 389 / 734

Date Code 20010625 Setting the Relay 9-51
SEL----311L Instruction Manual
51GT in the Zone 3 delay time of 20 cycles.
1 • 10
3
100
10
1
0.1
0.01
100 1 • 10
3
1 • 10
4
51G Overcurrent Protection
Z2 Time Delay
Primary Amps
Max. Regional
Current at Station S
for a Fault at
Station R
Time
(sec
on
ds)
M311L141
3538.9
51GT
Zone/Level 3 Directional Control
Zone/Level 3 direction: Forward, Reverse (F, R) DIR3 = F
Directional Elements (See Directional Control Settings in Section 4)
(Make setting ORDER if preceding enable setting E32 = Y or AUTO.)
Ground directional element priority: combination of Q, V, or I ORDER = QV
Reclosing Relay (See Tables 6.2 and 6.3)
(Make the following settings if preceding enable setting E79 = 1–4.)
Open interval 1 time (0.00–999999.00 cycles in 0.25-cycle steps) 79OI1 = 17.17
Reset time from reclose cycle (0.00–999999.00 cycles in 0.25-cycle steps) 79RSD = 1800
Reset time from lockout (0.00–999999.00 cycles in 0.25-cycle steps) 79RSLD = 1800
Reclose supervision time limit (OFF, 0.00–999999.00 cycles in 0.25-cycle
steps) (set 79CLSD = 0.00 for most applications; see Figure 6.2) 79CLSD = 0.0
Set 79OI1 to the minimum dead time that will allow the fault arc to extinguish and the arc path to
cool sufficiently for the reclose to be successful. A common estimate
1
is:
( )
cycles 17 . 17
5 . 34
230
5 . 10
5 . 34
kV V
5 . 10 T
LL
MIN
= + = + =