Schweitzer Engineering Laboratories SEL-421-4 - Page 1045

8.7
Date Code 20171006 Instruction Manual SEL-400 Series Relays
Monitoring
Circuit Breaker Monitor
Program the SELOGIC Control Equations for Trip and Close Conditions
Circuit Breaker Monitor Trip Initiation Settings: BM1TRP
NOTE: In the following discussion,
three elements are specified. There is
one element for each phase: = A, B,
and C. With three-pole breakers, only
phase A is used to represent the
entire breaker. Some three-pole relays
include A in the names and others
disregard it.
The relay employs SELOGIC control equations to initiate the circuit breaker mon-
itor. For Circuit Breaker 1, this setting is BM1TRP. These SEL
OGIC control
equations use Relay Word bits to determine when the circuit breaker monitor
accumulates circuit breaker operating parameters from phases A, B, and C. When
detecting a rising edge (a transition from logical 0 to logical 1) of the initiation
settings, the relay accumulates the interrupted rms currents and advances the trip
counter by one count. There are separate current accumulators and trip counters
for each circuit breaker pole. Table 8.4 shows the factory-default settings for cir-
cuit breaker monitor initiation.
NOTE: Factory defaults differ for
single-pole tripping and three-pole
tripping. Three-pole tripping uses the
single setting BM1TRPA for all three
poles.
Initiation settings can include both internal and external tripping conditions. To
capture trip information initiated by devices other than the relay, you must pro-
gram the SEL
OGIC control equation BM1TRP to sense these trips.
Table 8.4 Circuit Breaker Monitor Initiate SELOGIC Control Equations
Name Description Comment
a
a
See Ta bl e 8 .1 .
BM1TRPA BK1 monitor initiate equation If BK1TYP := 3
BM1TRPA A-Phase BK1 monitor initiate equation If BK1TYP := 1
BM1TRPB B-Phase BK1 monitor initiate equation If BK1TYP := 1
BM1TRPC C-Phase BK1 monitor initiate equation If BK1TYP := 1
Example 8.3 Circuit Breaker Monitor External Trip Initiation
Connect external trip signals to the relay control inputs. This example uses
input IN201; you can use any control inputs that are appropriate for your
installation. Control Input IN201, an optoisolated input, is located on the
relay I/O Interface Board #1.
If you want Circuit Breaker Monitor 1 to initiate for the trip elements TPA1,
TPB1, and TPC1, or for external trips, set these SEL
OGIC control equations
from the SET M ASCII command or the QuickSet Breaker Monitor Set-
tings tree view:
BK1TYP := 1 Breaker 1 Trip Type (Single Pole = 1, Three Pole = 3)
BM1TRPA := TPA1 OR IN201 Breaker Monitor A-Phase
Trip Initiate—BK1
BM1TRPB := TPB1 OR IN202 Breaker Monitor B-Phase
Trip Initiate—BK1
BM1TRPC := TPC1 OR IN203 Breaker Monitor C-Phase
Trip Initiate—BK1