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6.24
SEL-351-5, -6, -7 Relay
Instruction Manual
Date Code 20070117
Close and Reclose Logic
Reclosing Relay
Additional Settings Example 1
With skip shot setting:
79SKP =
50P2 * SH0
if shot = 0 (Relay Word bit SH0 = logical 1) and phase current is above the
phase instantaneous overcurrent element 50P2 threshold (Relay Word bit
50P2 = logical 1), at the instant of successful reclose initiation, the shot
counter is incremented from shot = 0 to shot = 1. Then, open interval 1 time
(setting 79OI1) is skipped, and the relay times on the open interval 2 time
(setting 79OI2) instead.
, note that the open interval 1 time (setting 79OI1) is a short time,
while the following open interval 2 time (setting 79OI2) is significantly
longer. For a high magnitude fault (greater than the phase instantaneous
overcurrent element 50P2 threshold), open interval 1 time is skipped, and
open interval timing proceeds on the following open interval 2 time.
Once the shot is incremented to shot = 1, Relay Word bit SH0 = logical 0 and
then setting 79SKP = logical 0, regardless of Relay Word bit 50P2.
Additional Settings Example 2
If the SEL-351 Relay is used on a feeder with a line-side independent power
producer (cogenerator), the utility should not reclose into a line still energized
by an islanded generator. To monitor line voltage and block reclosing, connect
a line-side single-phase potential transformer to channel VS on the SEL-351
as shown in
.
Figure 6.7
Reclose Blocking for Islanded Generator
If the line is energized, channel VS overvoltage element 59S1 can be set to
assert. Make the following setting:
79STL =
59S1 + ...
Table 6.5
Open Interval Time Example Settings
Shot
Corresponding
Relay Word Bit
Corresponding
Open Interval
Open Interval
Time Example
Setting
0
SH0
79OI1
30 cycles
1
SH1
79OI2
600 cycles
SEL-351
Bus 1
52
IA, IB, IC
VA, VB, VC VS
3-Phase
1-Phase
Generator
Содержание SEL-351-5
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