8.12
SEL-400 Series Relays Instruction Manual Date Code 20171006
Monitoring
Circuit Breaker Monitor
Primary load/fault current can indicate contact closing, contact opening, and arc
extinction, depending upon the actual circuit breaker monitor setup. You can
detect problems within the circuit breaker arcing chamber by timing the interval
from trip/close initiation to electric arc extinction.
Figure 8.6 Electrical Operating Time for Circuit Breaker 1 A-Phase
Example 8.6 Electrical Operating Time Settings
Use Circuit Breaker 1, a single-pole tripping circuit breaker, for this exam-
ple. Connect external trip signals to IN201, IN202, and IN203, and external
close signals to IN204, IN205, and IN206 for the A-, B-, and C-Phases,
respectively. This example uses control inputs IN201–IN206; you can use
any control inputs that are appropriate for your installation. The control volt-
age for this example is 125 Vdc.
Control Inputs IN201–IN206 are located on the relay I/O Interface board #1.
Set the electrical operating time threshold for the slow trip alarm (B1ESTRT)
at 25 ms, and the slow close alarm threshold (B1ESCLT) at 65 ms. Use your
company standard practices to determine these settings for your application.
For this example, enter the following settings.
B1ESTRT := 25 Electrical Slow Trip Alarm Threshold—BK1 (1–999 ms)
B1ESCLT := 65 Electrical Slow Close Alarm Threshold—BK1 (1–999 ms)
EB1MON := Y Breaker 1 Monitoring (Y, N)
BK1TYP := 1 Breaker 1 Trip Type (Single Pole = 1, Three Pole = 3)
BM1TRPA := TPA1 OR IN201 Breaker Monitor A-Phase Trip—BK1
(SEL
OGIC Equation)
BM1TRPB := TPB1 OR IN202 Breaker Monitor B-Phase Trip—BK1
(SEL
OGIC Equation)
BM1TRPC := TPC1 OR IN203 Breaker Monitor C-Phase Trip—BK1
(SEL
OGIC Equation)
BM1CLSA := BK1CL OR IN204 Breaker Monitor A-Phase Close—BK1
(SEL
OGIC Equation)
BM1TRPA
(A-Phase A Close)
A-Phase Open
A-Phase Open
Electrical Closing Time
BM1CLSA
(A-Phase A Trip)
Electrical Tripping Time
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