Sel 411L - Page 661

P.9.15
Date Code 20151029 Protection Manual SEL-411L Relay
Monitoring and Metering
Circuit Breaker Monitor
EXAMPLE 9.8 Pole Discrepancy Alarm for Circuit Breaker 1—No
Other Circuit Breaker Monitor Functions
Use Circuit Breaker 1, a single-pole tripping circuit breaker, for this
example. This example uses control inputs IN301, IN302, and IN303
for the A-, B-, and C-phases, respectively; you can use any control
inputs that are appropriate for your installation.
The control voltage for this example is 125 Vdc. Control Inputs
IN301–IN303 are located on I/O Board #2. Connect the circuit breaker
normally-open auxiliary circuit breaker (52A) contacts through
station battery power to IN301, IN302, and IN303.
Set the relay internal Relay Word bits to respond to these inputs by
using the
ACSELERATOR QuickSet Breaker Monitor (SET M) settings:
52AA1 := IN301 A-phase Normally Open Control Input—BK1
(SEL
OGIC Equation)
52AB1 := IN302 B-phase Normally Open Control Input—BK1
(SEL
OGIC Equation)
52AC1 := IN303 C-phase Normally Open Control Input—BK1
(SEL
OGIC Equation)
Connect external trip signals to IN301, IN302, and IN303, and external
close signals to IN304, IN305, and IN306 for the A-, B-, and C-phases,
respectively. This example uses control inputs IN301–IN306; you can
use any control inputs that are appropriate for your installation.
Set the pole discrepancy time delay (B1PDD) at 1400 ms. This time
delay assumes a dead time of 1000 ms plus a pole closing time of 100
ms (including contact latency), plus 20 percent (for security), rounded
to the next higher hundreds of milliseconds value. This pole
discrepancy time is longer than the single-pole open interval time
default of 900 ms; confirm that this is the case for your application
settings.
Enter the following settings:
B1PDD := 1400 Pole Discrepancy Time Delay—BK1 (1–9999 ms)
EB1MON := Y Breaker 1 Monitoring (Y, N)
BK1TYP := 1 Breaker 1 Trip Type (Single Pole = 1, Three Pole = 3)
The pole discrepancy timing window is B1PDD := 1400 (ms). Assertion
of the Relay Word bit B1PDAL indicates that the status of the three
Circuit Breaker 1 poles disagrees for 1400 ms or longer.
Circuit Breaker Inactivity Time Elapsed
The relay circuit breaker inactivity time monitor detects the elapsed time
(measured in days) since the last trip or close operation of a circuit breaker.
Use setting B1ITAT to set the circuit breaker inactivity time. An alarm Relay
Word bit, B1BITAL, asserts if the elapsed time exceeds a predefined setting.
This alarm is useful to detect circuit breakers that are not operated on a regular
basis. These circuit breakers can fail to operate when needed to perform a
protection trip.
EXAMPLE 9.9 Inactivity Time Settings
Use Circuit Breaker 1 for this example. To assert an alarm if Circuit
Breaker 1 has not operated within the last 365 days, enter the
following settings:
EB1MON := Y Breaker 1 Monitoring (Y, N)
B1ITAT := 365 Inactivity Time Alarm Thresh—BK1 (N, 1–9999 days)
Assertion of the Relay Word bit B1BITAL indicates that it has been
more than 365 days since the last Circuit Breaker 1 operation.