Schweitzer Engineering SEL-351P, Quick Start Manual

Page: 317 / 674

Date Code 990215 Close and Reclose Logic 6-23
SEL-351P Manual Técnico
Factory Settings Example
The skip shot function is not enabled in the factory settings:
79SKP = 0 (numeral 0)
The stall open interval timing factory setting is:
79STL = TRIP
After successful reclose initiation, open interval timing does not start as long as the trip condition
is present (Relay Word bit TRIP = logical 1). As discussed previously, if an open interval time
has not yet started timing (79STL = logical 1 still), the 79SKP setting is still processed. Once the
trip condition goes away (Relay Word bit TRIP = logical 0), open interval timing can proceed.
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.
Table SECTION 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
In Table SECTION 6: .5, 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-351P 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-351P as shown in Figure SECTION 6: .7.