Date Code 20010731
Breaker Logic
3-45
SEL-352-1, -2 Instruction Manual
Set DELOG to ON to enable the loss-of-dielectric detection logic. Modify the default logic by
setting DELOG = CUSTOM. When set to CUSTOM, all settings are shown including the
SEL
OGIC
control equations. Use these settings for a modified loss-of-dielectric detection logic,
or use it for an entirely different application. The default setting is DELOG = OFF.
One variation of the logic may be to only indicate a failure condition if the breaker is called upon
to trip and the pressure is low. To do this set DELOG = CUSTOM, and LODBF =
LT1D*!LT2D*TRIP3. This way, the lockout relay is tripped instantaneously if the pressure is
low and a trip initiation is received. An output contact could also be used to assert an alarm by
setting it as follows: OUT205 = LT1D*!LT2D.
Leak Timer (L2pu)
Range:
0–16383 cycles in 1/4-cycle steps
Use
SET <ENTER>
to access the L2pu setting and determine the delay between detection of a
drop in pressure below the high threshold (LOD2) and declaration of a pending failure (LODPF).
Set L2pu based on the preset pressure threshold and the minimum amount of pressure necessary
to trip the breaker. The pending failure bit LODPF should have enough time to trip the breaker
before the pressure drops below the second threshold.
For example, a breaker that has a nominal pressure of 400 psi and pressure level thresholds at 80
percent and 50 percent, may be set to trip the breaker after 5 seconds of decreased pressure, but
breaker isolation will occur if the pressure drops to the low threshold faster than 5 seconds.
LOD2 will assert and start the L2pu timer at 320 psi. With L2pu set at 300 cycles, the breaker is
tripped after 5 seconds of decreased pressure. If the pressure gets to 200 psi, which asserts
LOD1, the 60 delay timer starts. After 60 cycles, the breaker is isolated through the lockout
relay if 5 seconds have not expired.
B
REAKER
A
LARM
L
OGIC
Application Description
The BALRM bit indicates dangerous or abnormal conditions related to operation of the circuit
breaker. The BALRM (Breaker Alarm) setting defines which breaker monitoring conditions
assert the BALRM bit.
Operating Characteristic
When the BALRM bit asserts, the relay records the alarm in the breaker alarm report and the bit
remains asserted for one second.
Содержание SEL-352-1
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