Schweitzer Engineering Laboratories SEL-352-1 - Fault Current Logic Enable (FTLOG); Trip Timer Pickup Time (Ttpu)-Scheme 4

3-16 Breaker Logic Date Code 20010731
SEL-352-1, -2 Instruction Manual
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Figure 3.16: RMS Overcurrent Condition Detection
Fault Current Logic Enable (FTLOG)
Range: OFF, 1–5, CUSTOM
Use SET <ENTER> to access the FTLOG setting. Enable one of five schemes, select custom,
or disable fault current breaker failure protection.
Set FTLOG = OFF if you do not want fault current breaker failure protection. If you need logic
for your application different from that provided by any one of the five schemes, set FTLOG =
CUSTOM. When you select CUSTOM, all fault current settings are shown including the
SEL
OGIC control equations. Modify these settings to meet your specific application needs.
Fault Clearing Pickup Time (FCpu)–Schemes 1, 2, 3, and 5
Range: 0–8191 cycles in 1/8-cycle steps
Use SET <ENTER> to access the fault clearing pickup setting (FCpu). This setting determines
the time delay before the 62FC timer expires and asserts the FCAD timer output.
The recommended setting for FCpu is the nominal breaker operate time, plus the 50FT dropout
time, plus a safety margin.
Trip Timer Pickup Time (TTpu)–Scheme 4
Range: 0–8191 cycles in 1/8-cycle steps
Use SET <ENTER> to access this setting. It determines the time delay before the 62TT timer
expires and asserts the TTAD timer output.
The recommended setting for TTpu is the nominal breaker operate time, plus the 50FT dropout
time, plus a safety margin.